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42-volt electrical systemFrom Wikipedia, the free encyclopedia

Inautomobiles, a 42-volt electrical system was a proposed electrical power standard in the late 1990s

intended to allow more powerful electrically driven accessories, and lighter automobilewiringharnesses.Electric motorswere proposed to be used forpower steeringor other systems, providing more

compact installations and eliminating the weight ofdrive beltsor large wires forhigh-currentloads. Although

investigated as early as 1988,[1]

42-volt electrical components are now used in only a few automotive

applications, sinceincandescent light bulbswork well at 12 volts and switching of a 42-volt circuit is more

difficult.[2][3]

The proposed new standard was triple the voltage of existing "12 volt" systems. The higher voltage was

selected to provide greater power capacity for wiring and devices on one hand, and to stay under the 50 volt

limit used as a guideline forelectric shockhazard.

Although many manufacturers were predicting a switch to 36-volt (lithium ion battery) / 42-volt (charging

voltage) electrical systems, the changeover has not occurred, and the plans appear to have been

canceled.[2]

The availability of higher-efficiency motors, new wiring techniques and digital controls, and a focus

onhybrid vehicle systemsthat use high-voltage starter/generators has largely eliminated the push for switching

the main automotive voltages.[2]Applications that once were thought to require higher voltages, such as

electrical power steering, have now been achieved with 12 volt systems.[2]

The European auto manufacturerDaimler-Benzproposed a 42Vbrand name for the conversion

The Challenges and Opportunities of 42 Volt Systems

Qi Wang, Keithley Instruments, Inc.

9/30/2004 10:48 AM EDT

Intro

To meet ever increasing electrical power demands, automakers are moving to increase vehicle battery voltage from

today's 14V to approximately 42V. It has been more than 40 years since US carmakers switched from the standard

6V system, a change triggered by similar power considerations. During that time, vehicle electrical power

consumption has increased by more than 50 percent. Every year, new features and functions are added; the more

recent ones include cell phones, personal computers, and satellite navigation systems. Currently, less than 30
http://en.wikipedia.org/wiki/Automobilehttp://en.wikipedia.org/wiki/Automobilehttp://en.wikipedia.org/wiki/Automobilehttp://en.wikipedia.org/wiki/Wiring_harnesshttp://en.wikipedia.org/wiki/Wiring_harnesshttp://en.wikipedia.org/wiki/Wiring_harnesshttp://en.wikipedia.org/wiki/Wiring_harnesshttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Power_steeringhttp://en.wikipedia.org/wiki/Power_steeringhttp://en.wikipedia.org/wiki/Power_steeringhttp://en.wikipedia.org/wiki/Belt_(mechanical)http://en.wikipedia.org/wiki/Belt_(mechanical)http://en.wikipedia.org/wiki/Belt_(mechanical)http://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-0http://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-0http://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-0http://en.wikipedia.org/wiki/Incandescent_light_bulbhttp://en.wikipedia.org/wiki/Incandescent_light_bulbhttp://en.wikipedia.org/wiki/Incandescent_light_bulbhttp://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/Electric_shockhttp://en.wikipedia.org/wiki/Electric_shockhttp://en.wikipedia.org/wiki/Electric_shockhttp://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/Hybrid_electric_vehiclehttp://en.wikipedia.org/wiki/Hybrid_electric_vehiclehttp://en.wikipedia.org/wiki/Hybrid_electric_vehiclehttp://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/Daimler-Benzhttp://en.wikipedia.org/wiki/Daimler-Benzhttp://en.wikipedia.org/wiki/Daimler-Benzhttp://en.wikipedia.org/wiki/File:[email protected]://en.wikipedia.org/wiki/Daimler-Benzhttp://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/Hybrid_electric_vehiclehttp://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/Electric_shockhttp://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-wha-1http://en.wikipedia.org/wiki/Incandescent_light_bulbhttp://en.wikipedia.org/wiki/42-volt_electrical_system#cite_note-0http://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Belt_(mechanical)http://en.wikipedia.org/wiki/Power_steeringhttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Wiring_harnesshttp://en.wikipedia.org/wiki/Wiring_harnesshttp://en.wikipedia.org/wiki/Automobile


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percent of the energy in gasoline is used for locomotion; the remainder is wasted by inefficient components and

burned off as waste heat during engine idling.

The next generation of automobiles will have even more electronics and require a power source with an output of

more than three kilowatts, the limit of today's 14V system. A 42V system will deliver around eight kilowatts and allow

better management of the higher power requirements. Numerous other advantages include:

Reduced electrical current levels

Downsized wiring and electrical components

Lower electrical system cost

Reduced mass and volume

Improved fuel efficiency

Lower vehicle noise, vibration, and harshness

Improved system stability

A 42V system also sets the stage for advanced technologies that will allow a switch from mechanical belt-drivensystems to those that are electrically powered. Possibilities include electric power steering, electromechanical brakes,

electrical HVAC systems, electromagnetic valve trains, integrated starter-generators, and electronic ride control

systems. The so-called "beltless engine" of the future will be another reason for lower weight packaging (because

accessories can be located outside the engine compartment), leading to higher efficiency that improves gas mileage

and reduces emissions.42V Rollout

Initially, cars are expected to have a dual 14/42V system, which will help manage costs by avoiding a simultaneous

switch of all vehicle systems to the new 42V standard. During the gradual changeover, some components will operate

at 14V and some at 42V. This could persist for a few years, given that some 14V components, such as lamp

filaments, are more rugged and last longer than their 42V counterparts. It could be that certain components, such as

sensors, spark plugs, radios, and other electronic devices will always work better at 14V than at 42V.

Toyota Motor has already begun selling a 42V luxury sedan, but only in Japan. A few European cars have two lead-

acid batteries on board, so higher voltage electrical system should follow soon. About two dozen vehicles with varioustypes of 42V systems are in advanced design stages. US consumers will probably see the first dual 14/42V vehicles

on showroom floors beginning with the 2004 model year, when General Motors rolls out its first-generation 42V

system in a hybrid gas-electric pickup truck. Volume ramp-up is expected to start with the 2007 model year,

particularly in large and midrange automobiles and light trucks (especially SUVs), where power-hungry features, fuel

consumption, and emissions are becoming major issues. At least one forecast places production of 42V vehicles at

around 13 million units by 2010.

Challenges

Before 42V systems can be adopted widely, many engineering problems must be addressed, including the


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engine/electrical system architecture and a migration strategy (dual 14/42V systems vs. straight 42V systems). Short-

term challenges associated with dual voltage systems include more wiring, extra weight, and added complexity.

Regardless of migration path, suppliers need time to develop new components and a part identification system that

distinguishes between 14V and 42V parts.

Evaluation of Electrical and Electronic Components. While 42V is not far from 14V in physical terms, real-world

issues are a cause for concern. Current 14V designs won't automatically work at 42V; even simple fuses will not

migrate, let alone dimmers and active load controllers. Some fuse panel and harness makers have found thatcommon 14V mini- and maxi-fuses do not behave properly at 42V. They can fail to interrupt excessive currents

properly, causing serious overload conditions. Also, interconnection technologies have evolved for optimal cost and

performance in a 14V environment. The present design of connectors, circuit breakers, and relay contacts may not be

optimal at 42V. Therefore, manufacturers must re-evaluate component suitability for the higher voltage. Tests can

range from simple continuity tests to full electrical characterization of a component's functional performance at 42V.

Reliability Issues. At 42V and higher power levels, many components, such as wires and relays, experience electrical

stress that is three times higher than before. With higher stress, components tend to break down more often.

Therefore, component and module manufacturers have to perform more reliability testing, such as burn-in and

accelerated stress tests, to ensure adequate service life.

Safety Issues. Safe distribution of 42V power throughout a heavily optioned automobile also is a challenge. In the first

place, the 42V standard was established because higher voltages create human safety issues. For example, 50V can

stop a human heart, and anything higher than 60V requires more heavily insulated wires and connectors, which add

weight. To prevent fires, electrical distribution designs must allow for jump-starting at the higher voltage, and provideprotection if battery connections are reversed.

Component and Conductor Arcing. Relay, switch, and conductor arcing is another problem that must be addressed;

its potential for serious damage is greatly increased in 42V systems. Recent research shows that 42V arc energy is

50 to 100 times higher than in a 14V system. Such arcing can generate temperatures up to 1800F, ignite fuel vapors,

start a fire in plastic insulation, and even melt metal. Simply redesigning relays, switches, and fuses for higher voltage

and using flame-retardant materials is not a total solution; these component designs should suppress arcs. The same

is true for other connections, particularly those that could be opened during replacement of fuses, batteries, and other

components. Mechanical design features must ensure that electrical terminals are correctly seated and locked;

therefore, increased use of clips, clamps, and shields may be required.

Challenges

New Manufacturing and Test RequirementsImplementation of 42V systems will affect the design, manufacturing, assembly, and testing of most electrical andelectronic components. Electromechanical components such as alternators, motors, and starters may require moretime on field coil winding machines to get the same number of ampere-turns (given that the current and wire gaugewill be one-third of what it was for 14V devices). Other components will be redesigned or replaced. In many cases,suppliers will be asked to make them lighter, more efficient, and less expensive. This probably means thatsemiconductors will replace electromechanical designs in some switch and relay applications. This will call for higherpower devices, such as trench MOSFETs in higher voltage packages.While basic designs of existing assembly and test equipment should be adequate for 42V components, the higher

voltage will require some modifications. For instance, additional production testing may be required to verify arc

suppression and EMI/EMC compliance. To design the new 42V components properly, car makers and their suppliers

must understand critical engineering and performance issues. As a result, there will be increased R&D activity

involving the electrical characterization of devices and their designs. Typically, this entails electrical measurements

under various load conditions, insulation resistance and hi-pot testing, and very low resistance measurement of relay

contacts and connector terminals.

Simplifying and Speeding Up Measurements. Many 42V tests will require only common instruments, such as load

banks, high current power supplies, and DMMs. More specialized tests of conductors and insulators require

instruments designed specifically for the measurement extremes involved in low resistance, high resistance, and low

current testing. Complex devices, such as DC/DC converters, inverters, airbag igniter systems, and other electronic

controllers require more extensive testing and multifaceted test systems.

Many of these devices contain a large numbers of conductor pathways, have many sensor inputs (temperature,

vibration, humidity, etc.), and require multiple measurements, so signal switching systems are a valuable test tool.

Matrix switches support fully automated testing, reduce the number of instruments required, simplify test procedures,


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and reduce test time. In such a test system, the measuring instruments, signal switching, and other critical

components should be selected for ease of integration and optimum overall performance. Better still, use of a fully

integrated datalogging and switch system (Figure 1) eliminates the need to integrate many of the test system

components.

Figure 1. Keithley Model 2750 Multimeter/Switching System allows up to 2500readings/second across 200 channels of differential switching for analog and

digital I/O, plus 14 DMM measurement functions.

Application Specific Measurements. Many automotive electrical tests are essentially resistance measurements toverify continuity, or low leakage currents during hi-pot testing. Nevertheless, production testing may dictate multiplemeasurements in a specific sequence to check for proper assembly and wiring, which creates complexity in simpleresistance measurements.For instance, the electrical check on a vehicle's primary airbag inflator verifies proper characteristics in the

pyrotechnic initiator, a fusible wire with a typical resistance of around 2"3 ohms. A second test checks the safety

shorting clip (


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Figure 2. Hi-pot electrical test circuit using a Keithley Model 2790 Airbag InflatorTest System

Often, developing such a system from individual instruments and switching components, and then implementing it on

the production floor, can be quite costly. When available, an application-specific test system can save the user time

and money by providing tightly integrated components in a single ready-to-run unit. Figure 2 illustrates an airbag

inflator hi-pot electrical test circuit using such a system. The test system includes voltage and current sources

integrated with measuring instruments and a switching matrix.

Ethernet-Based Test Solutions. The switch to 42V systems will be on a "fast track," so test data sharing across the

enterprise will be important. Today, that often means feeding data to multiple departments across an Ethernet bus

(Figure 3). Having Ethernet-ready instruments with tightly integrated measurement and switching functions greatly

simplifies this task.

Figure 3. Typical distributed test and data sharing system. Burn-in chambers maybe located in either R&D or production departments, and may include vibration as

well as temperature cycling.

An additional benefit of Ethernet-based measurement solutions is that test engineers do not have to trade

measurement accuracy for convenience and cost-effective data collection. While PC plug-in cards provide low cost,


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measurement quality usually is much lower than that available with benchtop instruments. When the benchtop

instrument also has an Ethernet-ready interface, test engineers get the best of both worlds. This becomes

increasingly important in a production environment with many test stations or multipoint sensors. In such cases, it's

often more cost-effective to use an Ethernet-based instrument than to install multiple PC-based plug-in card

systems. The Look of the Future

Once the transition to a 42V power architecture is completed, wire gauges will be reduced, cable bundles will shrink,

smaller connectors can be used, and wiring weight will drop. Along with lower cable costs, labor costs will be reducedbecause of simpler installation. Full benefits of the new architecture will include:

Increased electrical power for cell phones, GPS units, audio systems, etc.

Reduced size and mass of motors and other accessories

More flexible, lighter weight packaging

More efficient operation (improved fuel economy and lower emissions)

The potential for redundant power sources

Faster temperature change in the HVAC system

Longer service life for many components and assemblies

Automakers are starting to convert to more powerful electrical systems.

In a popular song, folk singer Jimmy Buffet explains how "changes in latitude lead to changes in

attitude." That may be true in the Caribbean paradise he often sings about, but it doesnt apply to the

U.S. auto industry.

Engineers in Detroit still sit at the same latitude and try to maintain a positive attitude in todays cost-

conscious environment. However, the traditional electrical system that powers vehicles is about to

undergo a radical change.

Carmakers are starting to convert from 14-volt systems to a new 42-volt architecture. Ironically,

Detroit is situated at a latitude of 42 degrees North.

The dramatic voltage increase is necessary to support power-hungry vehicles, improve overall fuel

efficiency and reduce emissions. The transition to 42-volts will make it possible for engineers to

eliminate nearly all of todays inefficient mechanical and hydraulic systems. They will be replaced

with new technology, such as integrated starter-generators, steer-by-wire systems, brake-by-wire

systems, active suspension and electromagnetic engine valve systems.

"There are more revolutionary innovations waiting to debut on vehicles than any other time in our

industrys history, and 42-volt technology is the system that will help put many of these technologies

on the road," claims Walter Fields, vice president of automotive engineering materials at DuPont

Automotive (Troy, MI).

However, the new system will affect how alternators, connectors, motors, relays, starters, switches,

terminals, wiring harnesses and other components are assembled and tested. "Higher voltage


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systems will have far-reaching effects on the automotive industry, from component design and

manufacture to supply and assembly," says Dave Wright, director of advanced engineering at the

Packard Electric Systems div. of Delphi Automotive Systems (Troy, MI).

During the last 30 years, the power requirement for vehicles has risen more than 50 percent.

Todays typical luxury vehicle has more than 3 miles of wiring, 2,000 terminals, 50 connectors, 1,500

electronic circuits and 100 electric motors. Every year, more and more cars are equipped with new

features, such as cell phones, personal computers, satellite navigation systems and other onboard

communication devices. The next wave of automotive electronics will require more power as they

replace outdated mechanical systems.

The current 12-volt battery and 14-volt electrical system is being stretched to its power limits to run

navigation systems, lighting, engine electronics and dozens of other applications. Indeed, the typical

luxury vehicle demands up to 2.8 kilowatts of power, while the current 14-volt system only generates

about 3 kilowatts of power. By comparison, 42-volt systems will provide 8 kilowatts of power.

"For vehicles to continue to meet growing customer needs, electrical power must be increased,"

says Dennis Wiese, program executive for 42-volt architecture at General Motors Corp. (Detroit). "As

it is, wires and semiconductor switches get unmanageably big. It takes a high voltage to get them

back down to size."

Why 42 Volts?Automotive engineers and suppliers began discussing higher-voltage systems more than 10 years

ago, when they first noticed the difficulties associated with thick wiring bundles. Those problems

grew as they added audio, video and cellular components.

The industrywide standard of 42-volts was selected several years ago by an automaker consortiumled by the Massachusetts Institute of Technology (MIT, Cambridge, MA). The Consortium on

Advanced Automotive Electrical/Electronic Systems and Components, which operates under the

auspices of MITs Laboratory for Electromagnetic and Electronic Systems, is working to resolve

challenges surrounding 42-volt systems.

According to Tom Keim, principal research engineer and director of the consortium, 42 volts is three

Arial the voltage of the system now in use, which operates at 14 volts when the vehicle is running.

Instead of the traditional 12-volt battery, the new system will operate with a 36-volt battery.

Keim says 42 volts is the thresholdanything higher presents safety concerns. Because 50 voltscan stop a human heart, anything higher than that requires special safety systems to prevent contact

with wiring. In addition, any voltage above 60 needs more heavily insulated wires and connectors

that would add weight.

The auto industry has used 14-volt battery technology for more than 40 years. Automakers in the

United States switched from 6- to 12-volt batteries in the late 1950s. General Motors led the charge


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to the 14-volt power system. It introduced the first 12-volt battery in 1955. European car companies

were slower to adapt the technology, but finally made the big switch in the mid-1960s.

Because the auto industry has used 12-volt battery technology for more than 40 years, the switch to

42-volt systems is expected to create new challenges for manufacturing engineers.

Numerous BenefitsThe shift to a 42-volt standard will offer numerous benefits. For example, some devices that are now

driven mechanically will be driven electrically, since the needed power will be available. Components

such as air conditioning compressors, water pumps and power steering systems, will be operated

only on demand, instead of remaining a continuous parasitic load on the engine when they are in the

"off" part of their operating cycle. This feature will reduce fuel consumption and emissions.

Other benefits include:

Higher efficiency electrical systems. Conventional alternators are designed to optimize

current flow only at idle. A 42-volt integrated starter-alternator (ISA) will replace traditional

starters, belt-driven generators and flywheels. Vehicle engines will shut down instead of

idling at traffic stops. And an electric motor, rather than a belt to the engines crankshaft

pulley, will drive the water pump, reducing load on the engine.

Better components. A single device mounted on the end of the engines crankshaft will work

as a starter motor by spinning the crank at starting. An ISA will reach ignition much faster

than current starters, enabling the start-stop engine. The same device will serve as a

generator, charging the battery both directly from the engine and during braking, allowing

recovery of energy ordinarily dissipated in the brakes. This will help reduce brake wear.

Improved fuel economy. The ability to add technologies, such as start-stop with an ISA,

brake regeneration and torque boost, will improve fuel economy 10 percent to 15 percent. Reduced emissions. The internal combustion engines current slow start routine is where

most hydrocarbons are emitted into the atmosphere. Because 42-volt systems will enable

fast start-stop strategies, a high rpm start will eliminate the typical slow, rough start and

reduce emissions.

Reduced weight. Increasing the amount of current will allow for a 10 percent reduction in the

overall weight of wiring by reducing the size of heavy gauge wire. Wiring harnesses will

become lighter.

Solid-state circuitry. The 42-volt technology will make it more cost effective to use advanced

solid-state circuitry, which will allow for increased networking capabilities. Switching

semiconductors, for instance, are expected to cost less as the amperage decreases,enabling more electronic controls and customer-desired features.

Design flexibility. Components that have traditionally been clustered around the engine, such

as heating and cooling systems, will be more evenly distributed around the vehicle, enabling

sleeker, better balanced designs. There will be fewer belts and pulleys to contend with.

New technologies. With the 42-volt system, technologies that were previously impractical or

impossible will be feasible. Higher voltages will enable more effective and efficient use of


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drive-by-wire technologies, ride control systems, electronically heated catalysts and

electromagnetic valve systems.

Transition PeriodCars equipped with 42-volt electrical systems were expected to be on U.S. roads by 2003. But, a

longer than anticipated development time has pushed the technology off to a 2005 time frame.

"People were quick to figure out the benefits, but slower to look at the obstacles to making the

transition successful," says MITs Keim. "I think it will be a slow transition period. It will probably take

more than 10 years for the technology to become widespread." By 2010, the annual production of

42-volt vehicles worldwide is projected to be 13 million units.

But, some observers are skeptical of such predictions. "People in the auto industry are very reluctant

to make big moves like this," claims Richard P. Bodine Jr., chairman of Bodine Test and Assembly

Systems (Bridgeport, CT). He compares the transition from 14- to 42-volt electrical systems to

another revolution that shook the auto industry 20 years ago: the switch from carburetors to fuel

injectors.

However, Bodine says "its not a question of if; its when." Thats why American , European and

Japanese automakers are busy testing cars and trucks equipped with high-voltage components.

"We should begin to see 42-volt technology on the road in the next 2 to 3 years," says Delphis

Wright. "Widespread use is still somewhat uncertain, and could vary depending on various market

factors, including fuel economy requirements."

Volume ramp up is expected to occur around 2007. Until then, car companies will be slowly

introducing the technology in limited production, probably beginning with select 2004 model year

vehicles.

According to Norman Traub, director of 42-volt initiatives at the Society of Automotive Engineers Inc.

(Warrendale, PA), the first 42-volt vehicles will be marketed in countries with higher fuel costs and

more congestion, such as Japan. In fact, Toyota Motor Co. (Tokyo) recently became the first

automaker in the world to offer a hybrid 42-volt system as an option. Its Crown Royal Saloona

luxury car only available in Japanis 40 percent more fuel efficient than vehicles not fitted with the

system.

The first cars to feature the new technology in the United States will be sport utility vehicles (SUVs)

and light trucks. For instance, Ford Motor Co. (Dearborn, MI) plans to equip its popular Explorer

model with a 42-volt system featuring an ISA. General Motors plans to offer a 42-volt architecture in

a special pickup truck.


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Hybrid SystemsTo ensure a smooth transition, electrical systems will not be completely converted to 42 volts in one

giant step. Instead, the auto industry will go through a period when vehicles are equipped with both

14- and 42-volt architectures.

Traub says the dual 42/14-volt system is an interim step that is expected to be the norm for severalyears. Low-voltage devices, such as radios, will continue to use 14 volts. "Components that draw

large amounts of energy and run more efficiently at higher power, such as seat heaters, will benefit

from the 42-volt system," says Upton Bowden, a vehicle systems engineer at Visteon Corp.

(Dearborn, MI). "Its more economical."

Dual-volt systems will require two batteries: one traditional 12-volt unit and a 36-volt unit. The 36-volt

battery will take current from a new generation of higher voltage alternators, while the 12-volt battery

will recharge directly from the 36-volt unit.

"Dual-voltage systems are inevitable, because suppliers are not ready with all the 42-volt

components," says GMs Wiese. "It also becomes a question of how to roll everything out in a cost-

effective fashion."

The dual-volt alternative gives suppliers time to develop 42-volt components. "The cost to convert to

purely 42-volt would be cost-prohibitive right now," explains Bowden.

A gradual changeover minimizes the cost of simultaneously changing all vehicle systems to a new

standard. Also, not all components benefit significantly from increased voltage, such as certain

sensors and spark plugs. In fact, radios and incandescent lighting systems actually operate better at

12 volts.

The two-battery system presents short-term challenges, such as extra wiring, extra weight and

added complexity. In addition, suppliers need time to develop a part identification system to

distinguish between 14- and 42-volt components. Different sizes, colors and markings will probably

be used.

"As vehicles complete the transition to a 42-volt system, the power and signal distribution

architecture will be reconfigured to a single system," says Wright. "At that point, wire gauge will be

reduced, wire bundle sizes will shrink, smaller connection systems will be utilized, and mass and

cost will be substantially decreased. The installation and routing of the wiring system within the

vehicle will be simplified, and new vehicle design opportunities will be realized."

Unique RequirementsAuto part suppliers are scrambling to develop components capable of meeting the unique

requirements of 42-volt systems. All devices involved in power generation and energy storage are

affected, such as battery packs, drive motors and power electronics.


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"Material and components will need to significantly change to meet the new requirements," says

William Hsu, DuPonts technology vice president. For instance, upward shifts in heat-resistance and

electrical-property requirements will place some new challenges on thermoplastics.

"Some existing polymers wont work," claims Hsu. His company has developed a translucent grade

of nylon to replace polyethersulfone (PES) in fuse applications.

According to Hsu, 42-volt vehicles will need more plastic gears to serve in electrically actuated

systems. "Since 42-volt enables automakers to move belt-driven systems, like air conditioning units,

out of the engine compartment, plastics that couldnt stand underhood heat and mechanical loads

might now compete against metal," he points out.

"Some 42-volt systems will bring plastic gears closer to the engine. And these gears will have to go

beyond the standard domain of window lifters."

Safety and the threat of vehicle fires is an inherent concern for engineers working on 42-voltcomponents. For example, batteries must be developed to account for reverse battery voltage and

jump-starting at high voltages. Relay arcing is another problem that is being addressed by

engineers. Higher power relays, switches and fuses need to be developed. Many devices must be

redesigned or replaced with semiconductors.

When a relay opens and closes at 14 volts, theres a slight arc. But, at 42 volts, the arc becomes

much more pronounced. It could pit the contacts and cause premature wear on the device. Electrical

arcing can generate temperatures up to 1,832 F, melt metal or burn plastic, and ignite fuel vapors.

Arcing also is a concern when making or breaking connections, such as during fuse or battery

replacement. To address that challenge, relays and connectors must have wider spacing between

contact points to allow for differences in electrical arc.

"Because of the added potential for arcing in 42-volt systems, the major impact on wiring assembly

will be quality related," says Delphis Wright. "Ensuring that all terminals are correctly seated and

locked will take on additional importance. In addition, sealed connectors will be more commonly

used, increasing the number of components that a wiring assembly plant must deal with.

"More physical protection devices, such as clips, clamps and shields, may also be used. We are

investigating the use of flame-retardant materials for 42-volt connectors because of concerns

regarding arc containment and corrosion."

According to Visteons Bowden, many electrical parts and components will look similar whether they

run on 14- or 42-volt systems. "They will generally be the same shape," he points out. However, the

inside of motors, alternators and other devices will be noticeably different. For instance, more

windings of finer-gauge wire will be used in coils.


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A 42-volt vehicle will have lighter and smaller wiring, because amperage decreases when voltage

increases. For instance, an electric motor that takes 12 amperes at 12 volts requires only 4 amperes

at 36 volts. This will enable automotive suppliers to downsize wiring and shrink components.

Higher voltages will allow more effective and efficient use of thinner and lighter wiring. "More power

can be transferred with smaller wires, cables and connectors," says Wright, "which reduce

packaging sizes."

The tripling of voltage means the current carried by the wiring will shrink by two-thirds. That means

smaller wires throughout the vehicle, and bigger and smarter fuses. "But, excellent electrical

insulation and dielectric properties are vital," warns DuPonts Hsu. Indeed, the overall complexity of

connections will be increased, with more seals required.

"The main difference in the wiring system will be the need for more sealed connections, probably of

a different design than 14-volt connections," says Wright. However, the higher voltages and lower

currents associated with 42-volt systems will allow engineers to reduce wiring thicknesses byapproximately two-thirds. "There is the potential to reduce the size of wires that are currently larger

than 0.35 millimeter squared," explains Wright. "Circuits that are already 0.35 millimeter will likely not

be reduced due to physical strength concerns."

According to Bowden, 42-volt motors will need to spend more time on winding machines. "Theyll

require approximately three Arial as many turns as traditional devices," he points out. "But, since the

wiring will be thinner, it will fill the same amount of space. Suppliers may have to invest in better

winding equipment."

Suppliers are gearing up for this new manufacturing paradigm. For example, Xtreme Energy Inc. (St.

Petersburg, FL) has developed a brushless motor with a patented coil that it expects will be used in

many 42-volt applications. "We are automating the manufacturing process for our motor winding

technology to address high volume requirements and price point issues in the automotive market,"

says Kirk Barker, president.

Traditional 14-volt systems rely on bulky wiring. Low-voltage electricity must flow at a high amperage

to operate a vehicles accessories. That requires thick cables and harnesses. With 42-volt systems,

however, wiring bundle size may be as much as 20 percent smaller.

"Harness and connector manufacturers will need to develop innovative products that meet

automobile manufacturers needs in order to win contracts," says Jasmine Sachdeva, an analyst at

Frost & Sullivan Inc. (San Antonio). "A top priority for automakers is to reduce the size and weight of

wire harnesses and connectors.

"Growth in flat flexible cable and flexible printed circuit boards provide opportunities for growth.

Suppliers that can design and develop new technologies that allow for size, weight and cost savings

will definitely have a competitive advantage over other market participants."


13/23

Bowden says theres a good possibility that new technology will be used, especially if it helps make

wire harnesses smaller and more flexible. "Etched tri-metal and flat wire technology is not conducive

to 14-volt systems," he points out. "But, they may be attractive to 42-volt systems."

Assembly Challenges

High-voltage components, such as alternators, connectors, relays, starters and switches, will beassembled similar to traditional 14-volt parts. "Assembly methods will be basically the same,"

predicts Wright. In fact, he says the transition to 42-volt systems will have a minor impact on

assembly equipment.

"For the most part, current assembly equipment should be acceptable," explains Wright. "Only minor

modifications may be necessary." He believes current test and inspection equipment will be

acceptable, although slight modifications may be necessary, because additional quality checks may

be required.

Many suppliers are taking a wait and see attitude. "We wont learn more about the 42 -volt systems

until they are deployed and in production by the automobile manufacturers," says Peter Doyon, vice

president of product management at Schleuniger Inc. (Manchester, NH).

Some equipment manufacturers are concerned about standards changing as development efforts

continue. According to SAEs Norman Traub, when systems reach the production phase,

standardization will be needed to encourage suppliers to produce higher volumes.

No matter what transpires or when it happens, Richard Bodine anticipates there will be a

tremendous opportunity to use new assembly equipment. "Suppliers will be asked to make new,

lighter, less expensive and more efficient devices," Bodine predicts. "If you have a chance to make a

product, such as a motor, half as big because of the inherent advantages of 42-volt technology, whynot use new assembly lines and new equipment to produce it?"

Bodine believes the new generation of electrical components will undoubtedly be smaller than what

were used to seeing today. "All you have to do is take a look under the hood of a 1948 Packard," he

explains. "The 6-volt starter motor is much bigger than what youll find in one of todays 14 -volt

vehicles."

Final vehicle assembly will also be affected by 42-volt technology. "If electrical troubleshooting is

required at the assembly plant, it will need to be done with the battery disconnected," warns Wright.

"Additionally, it will probably be desirable to connect the battery after all electrical connections havebeen made, which is not a requirement today.

"At the vehicle assembly level, some additional components will be required," adds Wright. "These

include two batteries, a DC/DC converter and potentially other devices related to circuit protection

and battery disconnection. Given the current packaging challenges faced by the auto industry, these

additional components will exacerbate the situation further, which may challenge the assembly

process somewhat."


14/23

Eventually, 42-volt systems may spur other changes in the way in which vehicles are assembled.

For instance, the incandescent bulbs currently used in lighting systems may eventually be replaced

with light-emitting diodes that can withstand higher voltages and are much more energy efficient.

And steer-by-wire systems may lead to the eventual elimination of traditional steering wheels in favor

of joysticks. When that happens, it will probably inspire Jimmy Buffet to write another song.

Advantages of a higher voltage

Motivation for increased voltage - higher demand by accessories such as air conditioning, power steering,

adaptive suspension, electronically-controlled valves. Could need several kw electric power on a vehicle,

compared to about 1 kW in a passenger car today. More power needs more current at 12 v, larger and

heavier wires. A higher voltage would be useful.

All-electric drives would allow unused loads to be switched off, reducing parasitic drag on the engine.

Applications in both mass-market cars and for military vehicles which could use electrically poweredsystems for weapons and sensors.

The reason to go to 42 V is that this is about the highest voltage that can be used without running into

safety codes on insulation and contact - many codes only regulate equipment for voltages 50 v and

higher. Using 42 volts allows the same wires to carry 3 x the power as a 12 volt system.

With a lead-acid battery system, 6 cells for a nominal 12-volt system needs almost 14 volts for charging

the battery. Using 3 times as many cells gives 36 volt "nominal" but a 42-volt charging system. The

convention seems to be use the charging voltage - a lead-acid "12 volt" battery with 12 volts on its

terminals is essentially a dead battery, when charged it will show 13.6 v or more.

Discuss why not just go to 24 v (28 V charging)- which is well established in heavy trucks. maybe an sAE

reference describes this?

Just a comment, "about 1 kW in a passenger car today". That is huge amount of power, I know

this is just a talk page but cars with 42A electrics? Surely this is an exceptionally large power

drain. Headlights take about 100W and that is a major drain on many (IMHO most) car electrical

systems.Mtpaley(talk) 22:43, 16 April 2010 (UTC)

Well, let's see. A kilowatt at 12 V would be closer to 83 A. An ignition system takes substantial

power (10 A, perhaps?). Low beam is 2 x 55 watts, high beam is 2 x 65 watts on some cars

anyway. My car has various motor operated gizmos like a sun roof and power seats, and electric

seat heaters. There's more than just headlamps - marker lights, turn signals,daytime running

lights, brake lights, dashboard lights. The stereo takes a couple of amps. There's a powerful

blower for the heating and air conditioning. Many cars have electric radiator fans which are pretty

big loads (20 or 30 A?). And that's not counting things like electric power steering, adaptive

suspensions, electric power brakes, and many other toys and gadgets that the Car of the Future
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15/23

will have. I think it's a reasonable statement, but my best reference is packed away at the

moment. --Wtshymanski(talk) 14:38, 17 April 2010 (UTC)

[edit]System components

42-volt system would need a newalternatorandbattery. Could use a combined starter motor and

alternator, controlled by power electronics - combined with a 42 V battery bank this is used to create"mild hybrids" which use an electrical assist to add several hp for acceleration and to idle-stop

engines instead of idling at standstill. To power 12-volt accessories would use either a solid-state

converter or a second 12 volt battery recharged from the 42 volt system. Separating the engine

cranking battery from the ignition and accessory battery would solve one big problem with automotive

electrical systems.

[edit]Limitations and obstacles

It's hard to break direct current at voltages higher than 12 V because there's no natural current

reversals as found in AC circuits. The same switch that is rated to interrupt 15 Amperes at 120 v AC

might only be rated 1 Ampere at 120 v DC. 12-volt switches haven't needed design features to limit

arcing such as spring-loaded fast break contacts, or arc containment and dispersal features as foundin higher-voltage dc switching devices.

Not all the wires get smaller - very fine wire breaks easily, so devices that only draw an ampere or so

at 12 V will not get smaller wires. Maybe 1/3 of the wires in a car get smaller at 42 volts.

Corrosion is a problem according to[1]

Incandescent bulbs of the sizes used in cars work quite well at 12 v and are cheap and simple. 42 V

gives no advantage for LED lamps, but might be useful for hid headlamps which have relatively high

power.

A great deal of auto electronics works well at 12 v and developing semiconductors to switch andtolerate a 42 v environment is a challenging field of development. Low-power electronics doesn't

benefit from 42 v (computers, navigation systems), 42 V might help high-power sound systems. Chief

advantage is for electronics controlling mechanical systems such as engine valves and suspension. If

42 V devices all switched electronically, avoids the problems with snap switches.

[edit]Slow introduction

Toyota produced a low volume luxuryToyota Crownwith 42 V electrical system, sold only in Japan.

General Motors is incorporating 42-volt elements in vehicles like the 2005Silverado hybridtruck.

[edit]Merge from42V?

I have a slight preference to merge material from42Vto this article, on the grounds that "42-volt

electrical system" is more descriptive than the curt "42V". I am biassed, of course -[2]. --

Wtshymanski(talk) 14:10, 25 November 2011 (UTC)

I agree with you on the direction of the merge. However, noone seems to have started a section

on a Talk page that actually contains the merge proposal, with the rationale from the nominator.
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16/23

Someone may feel free to invite me back if that ever happens. Cheers. N2e(talk) 15:33, 25

November 2011 (UTC)

Why, this is that talk page discussion. The rationale is pretty obvious - same topic, two articles,

should be one article. --Wtshymanski(talk) 17:50, 25 November 2011 (UTC)

Merge makes sense; using this name for the merged page makes sense.- -NapoliRoma(talk)

00:52, 26 November 2011 (UTC)

42 Volt Systems

About 40 years ago automotive electrical systems moved from a 6-volt standard to 12/14 volts. Now

the change to 42-volt systems - which use a 38 volt battery and 42 volt alternator output - is being

proposed. Two multi-company committees are working on the new standard. At the Massachusetts

Institute of Technology, the Consortium on Advanced Automotive Electrical/Electronic Components

and Systems includes General Motors, Ford, DaimlerChrysler, BMW, PSA-Peugeot/Citroen, Renault,Volvo and automotive electronics suppliers Delphi, Bosch and Siemens. In Europe, Sican - an

organisation in Hanover, Germany - is working with major German carmakers and component

suppliers to formulate the new 42 volt standard. The commitment to the new standard is high; for

example, the French automotive component company Valeo has eight of its nine component divisions

working on products using 42 volt technology.

The commercial risks to a car manufacturer of swapping to 42 volt technology and at the same time

undertaking a major re-design of all the electronics in the car means that initially, dual 12/42 volt

systems are likely to be introduced first. As Delphi state, "The increase in voltage means rethinking

and possibly redesigning everything from light bulbs to major components". DaimlerChrysler: "We

have decided to additionally retain a 12 volt supply so that components in standard use today can

remain operable."

As indicated, the major benefit of the higher voltage is in the reduced current flows that are then

possible for the same power consumption. Wiring bundles could be as much as 20 per cent smaller, in

turn reducing cable mass and so benefiting fuel consumption and emissions. Says DaimlerChrysler,

"We see the development of a 42-volt net not only as a technological necessity, but as a contribution

to lessening the environmental burden."

A number of approaches to the introduction of 12/42 volt car systems has been proposed:
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17/23

Single voltage generation and single voltage energy storage - a 42 volt alternator charges a 36

volt battery which services 36 volt loads, with a DC/DC converter used to charge a 12 volt battery that

services 12 volt loads;

Single voltage generation and dual voltage energy storage - a 42 volt alternator charges the 36volt side of a dual 12/36 volt battery, with a DC/DC converter used to charge the 12 volt portion ofthe battery;

Dual voltage generation and single voltage energy storage - where a dual 14/42 volt alternator

charges two separate systems, one 12 volts and the other 36 volts;

Dual voltage generation and dual voltage energy storage- where a dual 14/42 volt alternatorcharges a dual 12/36 volt battery.

Benefits to current technology from using 42 volt systems are:

Current Technology Benefits of 42 volt Architecture

Electric power steering More power, improved fuel economy

Electric brakes Redundant power supplies

Power windows, power seats, power

hatchback lifts

Reduced size and mass of motors; more

efficient operation

Heated catalytic converter Lower emissions; quicker light-off time


18/23

Heating, ventilation, airconditioning blower

motors and cooling fans

Greater efficiency; smaller/lighter units;

flexible packaging

Mobile multimedia More power available for video, mobile

phones, navigation systems, audio amplifiers,

fax machines

Electric water pumps Improved efficiency; longer service life

Selected engine management system

components (eg exhaust gas recirculation

valves, ignition systems, control actuators)

Reduced size and mass; increased

performance

Fuel pumps Reduced size and mass

Heated seats Faster heating, more efficient operation;

increased power

Car technologies that are yet to be introduced but which would also substantially benefit from higher

car voltages are:

Future Technology Benefits

Electric supercharging Higher engine efficiency

Ride control systems Improve ride, handling and vehicle stability

Brake by wire Improved vehicle packaging and vehicle

performance

Steer by wire Enhanced performance; improved packaging;

improved passive and active safety

Electromagnetic valve control Lower emissions; optimal power; individual

cylinder control; lower cost

Integrated starter/generator Faster starts; quicker charging; design

flexibility; low noise and vibration; improved

fuel economy

New Alternator Designs

The very high electrical power demand of current cars is also resulting in the development of more

efficient alternator designs. One approach is to water-cool the alternator, circulating engine coolant

through passages cast in the alternator housing. In some cases, the alternator is entirely surrounded

by a water jacket.

A liquid-cooled alternator design was first introduced (in very small numbers) in passenger cars in

1995. That design used two conventional alternators mounted on the one shaft, and developed

14V/220A with low noise levels. BMW has since introduced (on cars such as the 750iL mentioned

above) a water-cooled alternator that uses a single brushless design developing 14V/150A. The BMW

alternator uses liquid cooling for two major reasons: to reduce by up to 3dB the alternator noise

associated with normal fan-cooling; and to increase electrical performance. Other advantages of the

design include:


19/23

Rapid engine warm-up due to the utilisation of alternator waste heat;

packaging advantages due to the absence of an alternator aircooling duct;

a longer alternator life;

good fording ability for the car.

However, probably the most dramatic development in alternator technology is the Integrated Starter

Alternator Damper (ISAD) being developed by German company Continental ISAD Electronic SystemsGmbH & Co. The ISAD combines the function of a starter motor and alternator into one assembly that

is located between the engine and gearbox. ISAD is able to generate output voltages of 12, 24, or -

significantly - 42 volts. The device eliminates the:

conventional starter motor and solenoid;

flywheel;

conventional alternator;

alternator pulley and belt drive system;

and in some cases, the harmonic balancer.

Both BMW and Citroen have shown vehicle prototypes using 42 volt ISAD systems. In a car equippedwith a 42 volt ISAD system, each normally belt-driven device could be replaced with an electric motor.

In some cases this would have significant advantages - the airconditioning compressor could be

located close to the cabin instead of at the front of the engine, for example.

Conclusion

Cars featuring water-cooled alternators or combined starter/alternators, 42-volt wiring and much

higher electrical loads are likely to be appear in the next few years. No longer will "12 volts"

necessarily mean car voltages....

Technology evolution

Raising the voltage in automobiles is the hot topic of international forms such as Europe's

SICAN and Forum Bordnetz, and the MIT-based Consortia on Advanced Automotive

Electrical/ Electronic Components and Systems. The voltage debate has more momentum

in Europe, where high-priced fuel makes a better case for paying a premium to get

improved vehicle efficiency. Additionally, luxury vehicles from manufacturers like Mercedes-

Benz and BMW, are better able to absorb the cost of new technology. In fact, supplier


20/23

sources say Mercedes-B e n z will be first to market a 42-volt vehicle with the industry's first

electronically-actuated valvetrain (see story p. 19).

The standard that was recently agreed to by automakers and suppliers in Europe and the

U.S. is a 36-/42-volt standard. Specifically, it is a tripling of the current voltage in a vehicle

for both battery output (12 to 36) and generator output (14 to 42). The vehicles will likelyhave dual batteries (12-volt and 36volt) or at least a stepped-down 12volt circuit onboard so

that all electrical components don't have to change over at once.

"There will be dual voltage as far as the eye can see," says Gary Cameron, chief engineer

at Delphi's Energenix Center.

The new standard was driven by the industry wanting the highest possible voltage, with the

most safety. Also, a European safety regulation specifies that any voltage above 60 needs

to have more heavily insulated wires and connectors. That would add weight and defeat

many of the advantages gained in other areas.

Wiring Switches and Connectors

One of the biggest gains in ahigher voltagesystem comes in wiring and signal distribution.

"In theory, we can reduce a wire gauge to one-third the size by tripling voltage," says Chuck

Vink, supervisor of electrical electronic architectures for Delphi Packard Europe. "I say in

theory, because wires reach a minimum size for manufacturability and durability and just

won't get any smaller." Vink says a realistic reduction in mass and volume is about 25%

including connectors and insulation. That also means lower cost, easier packaging and

smaller body perforations for lower vehicle NVH. Higher voltage should also signal the end

of mechanical relays and bring the entire vehicle to solid state switching--which is exactly

what is needed to promote widespread multiplexing.

Additionally, solid state circuits can be made "smart" featuring diagnostic capabilities and

circuit protection that would eliminate traditional fusing. "All of this affects the connector side

of the business too," says Dick Granitz, associate director of interconnection research

atAMP Inc. "Not only does this mean smaller connectors and less weight, it means your car

will become a network on wheels."

Granitz says the auto industry will go to switches more like the keyboard on a computer as

opposed to heavy relays. He even confides that AMP is looking at plug-in "option" cards

that slip into a motherboard for adding things like power windows or mirrors or heated seats

(see story p.41). Vink agrees with the computer analogy and says the industry will adopt

easy-to-install insulation displacement connectors (IDCs), which are similar to those used

on ribbon connectors in a PC.

Lighting

Fundamentally, the news of a voltage upgrade is not good for the lighting industry.Keith

Bucher, Cooper Automotive's engineering manager for light sources and interior lighting,

says higher voltage is the wrong direction for lamps with filaments.
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"The problem with bulbs is that you need the wattage to stay the same even if you drop the

current by one-third," Bucher says. "To do that, the tungsten filament has to get thinner and

longer and that means terrible problems with shock and vibration." And Bucher notes that

tungsten is the only material that will incandesce at such a high temperature without melting

or flowing.

For headlamp applications, one solution could be more widespread use of high-intensity

discharge lamps, since they need higher voltage anyway. The same would be true for neon

in tall lamp or interior applications. "With both technologies you are just exciting gasses, so

you design for the voltage," says Bill Buchman, director of sales and program management

at Cooper. "But there will still be higher cost implications whether they are at 12-volt or 42."

Potentially more expensive is redesigning over 100 near-commodity lamps in cars. One

alternative is a distributed lighting system that allows a redesign of just a few lamps as a

light source, which could then be "piped" through the car using fiber optics. A more frugal

solution is to maintain the 12-volt circuit just for the lights.

Batteries

Forty-two volt vehicles will likely have two batteries (one 36-volt and one 12-volt). This

actually has engineering advantages for battery suppliers. "As a battery designer, we know

that you can optimize a battery for starting or optimize it for reserve, but not both," offers

Bob Gruenstern director of engineering at Johnson Controls Battery. "So we would make

the 36-volt battery using our thin-metal foil technology for lots of power, and our reserve

battery with bulkier materials for capacity."

Gruenstern says thin-foil technology would permit a starting battery that's similar in size to

today's 12-volt battery. The reserve unit would be motorcycle battery-sized, that could be

placed almost anywhere in the car.

Only the 36-volt battery would take current from a new generation of higher voltage

alternators (see story p. 35), while the 12-volt reserve battery would recharge directly from

the 36-volt.

Automakers are working on onboard DC-to-DC converters that would still allow a

conventional car to jump-start a higher voltage vehicle.

A key issue for the new battery is the type of terminals it will use, which according to AMP's

Granitz, could be designed in a non-reversible way that would result in lower-cost

semiconductors.Semiconductors and Electronics

Higher voltage has no direct benefit to semiconductors, but reworking the electrical system

could profoundly change these components. Today's automotive semiconductors are a

special type, protected against situations like reverse polarity from an improper jump start,

or a load-dump fault that is essentially an uncontrolled voltage spike from the alternator.

Every semiconductor has its own built-in protection.


22/23

"The 42-volt standard can save money in the semiconductor business by controlling voltage

transients," says Randy Frank, marketing manager at Motorola Semiconductor Products.

Frank explains that a carefully regulated 42-volt system could continue to use today's

semiconductors since they are designed for up to 60 volts. But if the 12-volt circuit on the

new vehicles was controlled to no more than 20-volt transients, a smaller, cheaper and

more efficient component could be introduced. And cheaper semiconductors are the key topractical multiplexing.

"I'm guessing you could pull 30% of the cost out of semiconductors if you protected them

from damage up front, instead of building it into every one," says AMP's Granitz.

"I'm fairly certain you'll see more controlled voltage and batteries with keyed connectors that

you simply can't reverse polarity on. This is just too much of an opportunity not to address

these things."

Motors and Solenoids

In terms of mass savings, some of the biggest gains in the move to 42 volts will come from

motors and solenoids. "I think we might be able to realize a mass reduction of 20%," says

Reiner Emig, executive vice president of engineering at Robert Bosch Corp., "well into a

two-digit pound number for a vehicle."

In the case of a simple device like a solenoid, the size and weight reduction is almost linear

with the voltage increase. For motors, the savings are slightly less dramatic because the

mechanical parts like gearing would remain the same size because they would deal with the

same loads and forces.

Even so, the space where motors are generally packaged is precious real estate, and

smaller units could mean thinner doors that offer more passenger room, or even additional

storage space under seats.

One message is clear in the move to 42 volt: The industry doesn't want to do what it did

when it went from six volts to 12. Back then, all of the weaknesses of the existing standard

were brought forward and in some cases exaggerated by the higher voltage. This time,

automakers are planning to use the clean-sheet approach to their advantage.

"I'm guessing you could pull 30% of the cost out of semiconductors if you protected themfrom damage up front, instead of building it into every one," says AMP's Granitz.

"I'm fairly certain you'll see more controlled voltage and batteries with keyed connectors that

you simply can't reverse polarity on. This is just too much of an opportunity not to address

these things."

Motors and Solenoids


23/23

In terms of mass savings, some of the biggest gains in the move to 42 volts will come from

motors and solenoids. "I think we might be able to realize a mass reduction of 20%," says

Reiner Emig, executive vice president of engineering at Robert Bosch Corp., "well into a

two-digit pound number for a vehicle."

In the case of a simple device like a solenoid, the size and weight reduction is almost linearwith the voltage increase. For motors, the savings are slightly less dramatic because the

mechanical parts like gearing would remain the same size because they would deal with the

same loads and forces.

Even so, the space where motors are generally packaged is precious real estate, and

smaller units could mean thinner doors that offer more passenger room, or even additional

storage space under seats.

One message is clear in the move to 42 volt: The industry doesn't want to do what it did

when it went from six volts to 12. Back then, all of the weaknesses of the existing standard

were brought forward and in some cases exaggerated by the higher voltage. This time,

automakers are planning to use the clean-sheet approach to their advantage.

42 valt system

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