set up a buffer zone around the vehicle

Hybrid and Alternative Fuel VehiclesBy James D Halderman and Tony Martin

© 2009 Pearson Education, Inc.Pearson Prentice Hall

Upper Saddle River, NJ 07458




OBJECTIVES

After studying Chapter 13, the reader should be able to:1. Explain the operation of a Ford/Mercury hybrid electric

vehicle (HEV).2. Describe the features of a Ford/Mercury HEV.

3. Discuss the safety precautions to be followed whenever working on a Ford/Mercury HEV.

4. Explain how the electronically controlled continuously variable transmission (eCVT) allows the Ford/Mercury HEV to

achieve maximum efficiency.5. Describe the service procedures for Ford/Mercury HEVs.




The Ford Escape and Mercury Mariner share most of the same components and, except for trim and other non-hybrid related features, are basically the same.




Interior differences include:Center console gearshiftUnique interior trim

Offers seating for up to five and includes the same 60/40 split folding rear seat

Efficient packaging of the hybrid technology, such as locating the battery pack at the rear cargo floor

A unique gauge package features an economy indicator with green zone that shows when the vehicle is operating on battery

power.




The Escape/Mariner hybrid power train system includes the following components:

A 2.3-liter four-cylinder gasoline ICE featuring Atkinson-cycle combustion and producing 133 horsepower at 6,000 RPMA 70-kilowatt (equivalent to 93 horsepower) electric traction

motorA generator-motor that recharges the batteries, starts the engine, and controls the CVT function of the transaxle

A special electronically controlled continuously variable transmission (eCVT) used to drive the front wheels in a

front-wheel-drive Escape/Mariner or all four wheels with the optional Intelligent 4WD System™

A 330-volt nickel-metal-hydride battery pack located in the rear cargo floor




An electronic vehicle system controller manages charging, drive assist, and engine starting functions

such as the idle stop function.




The Ford/Mercury Hybrid uses a lightweight 2.3-liter four-cylinder ICE.

The engine also features:Double-overhead-cam design with four valves per cylinder

Pent-roof combustion chambers, and centrally located spark plugs

Direct-acting mechanical bucket tappets that require no lash adjustment during a 10-year, 150,000-mile service life

Four orifice-type fuel injectors that provide a better spray pattern and finer atomization than is possible with more

common single-orifice injectors Butterfly valves positioned in the intake runners that

restrict airflow at low speeds to induce tumble as the fuel-air mixture enters the combustion chamber

Counter-rotating balance weights that help eliminate vibration




The Ford/Mercury hybrid ICE uses a special Atkinson combustion cycle for improved efficiency. This consists of a 12:1 compression ratio for maximum

efficiency and late-closing intake valves to reduce pumping losses.




The air inlet to the Ford/Mercury hybrid ICE uses a charcoal filter to trap any hydrocarbons that may be in the intake manifold when the engine is turned off. When the engine starts, airflow through the charcoal draws out the hydrocarbons, which are then burned in the cylinders rather than being released into the

atmosphere.




The transaxle also routes a portion of the power produced by the engine to a generator. The transaxle includes the

following components: 36-kW permanent magnet AC generator motor70-kW permanent magnet AC traction motorPlanetary gear and final drive gears

Integrated power electronics/voltage inverter




Four Modes of Operation

The transaxle operation takes place in one of four modes, as follows:

Series Mode.1. Used only when the vehicle is not moving and the

ICE is running. The transaxle will not enter this mode when it is placed in the

“neutral” position.2. The ICE is running to charge the batteries or for

climate control reasons. The ICE may also be running to keep the catalytic converter

warm.




Positive Split Mode.1. The ICE is running and driving the generator motor

to produce electricity.2. Power from the ICE is split between the direct path

to the drive wheels and the path through the generator motor.3. This is the mode that is normally used while under cruise

conditions.




Negative Split Mode.1. The ICE is on and the generator motor is being used

to consume electrical energy to reduce engine speed.2. The traction motor can operate as a motor or a generator.3. This mode is used during highway driving when the ICE has to be on but the HV battery pack does not need to be charged.




Electric Mode.1. The vehicle is being propelled using stored

electrical energy only using the traction motor.2. This is the preferred mode whenever the required power is

low enough for the electrical system to handle.3. This mode is used in reverse because the ICE cannot

deliver reverse torque through the transaxle.




Regenerative braking is automatically controlled by the PCM along with the Brake System Control Module (BSCM). This electric regenerative braking represents a major

part of the hybrid’s efficiency advantage over conventional vehicles.




GENERATOR MOTOR

The generator motor handles three tasks:1. The primary responsibility is generating electric current.

2. The second task is restarting the ICE after shutdown, after a stop, or after coasting.

3. The generator is also used to control the drive ratio in the transaxle's planetary gearset so that the ICE operates at

its most efficient load and RPM.




HIGH-VOLTAGE BATTERY PACK

The HV battery pack consists of 250 nickel-metal-hydride D-size cells connected in series, packaged

under the cargo floor.




The high-voltage charging system is a floating ground system. A floating ground system means that the neither the power side nor the return side of the circuit is electrically connected

to chassis or body ground.




Battery Temperature Control

The high-voltage (traction) battery pack works best if it is not too cold or too hot. The system is configured so that

fresh air can be brought in for battery cooling, or air can be recirculated through the battery pack housing. Cooling fans are located inside the traction battery module and these

circulate air over the high-voltage battery and the electronics located in the battery case.




Total battery capacity is 5.5 ampere-hours (Ah); operating voltage varies between 216 and 397 volts. In the discharge

mode, the battery pack can deliver up to 39 kilowatts of power and its maximum recharge rate is 31 kilowatts.




Use the 12-Volt Battery to Charge the High-Voltage Batteries

This is achieved by sending the 12 volts to a special DC-DC converter located in the traction battery case, where the voltage is increased and then sent to the high-voltage

batteries.The switch used to start this recharging procedure is

located behind a panel on the driver’s side kick panel. When the switch is turned on, the 12-volt battery will charge the

high-voltage batteries.




12-Volt Battery

The 12-volt battery is a conventional lead-acid automotive battery.

The battery has three major functions:Storage of electricity for later use

Voltage stabilizer for the electrical system Temporary power when electrical loads exceed the DC-DC

converter output currentThe 12-volt battery is located under the hood.




ELECTRONIC CONTROLLER

An onboard electronic device (AC to DC converter) inside the transmission control module (TCM) converts the AC current

produced by the generator motor and the traction motor to DC voltage suitable for recharging the battery pack.




DC-DC Converter

The DC-DC converter is controlled by the PCM and is located under the hood on the passenger side of the

vehicle in front of the shock tower.




ELECTRIC POWER ASSIST STEERING (EPAS)

The electric power assist steering (EPAS) system consists of:Power steering control module

Electric motor Torque sensor

Rack-and-pinion steering gear




The electrical power steering system powers itself down within three seconds after the key is moved to the OFF

position.




If the vehicle speed is missing or out of range, the power steering control module defaults to a reduced level of assist. If the vehicle speed returns to the correct in-range values, the power steering control

module adjusts the steering assist level accordingly.




REGENERATIVE BRAKING SYSTEM (RBS)

The Ford Escape and Mercury Mariner are equipped with a regenerative braking system (RBS). The brake system used on the Ford/Mercury hybrid is a series regenerative braking

system in which power train braking is used first, up to the limits of the power train torque capacity and battery

capacity.




SERVICE PROCEDURES

The Ford/Mercury hybrid vehicles are serviced the same as conventional vehicles except for certain precautions.




Set up a buffer zone around the vehicle.




Remove the service disconnect plug.




Remove the service disconnect plug and place in the servicing shipping (3)

position.




Wear high-voltage linesman’s gloves with leather gloves over them whenever

working on the high-voltage circuits.Always wear a face shield.

Have available a fiberglass hook outside the buffer zone so that a technician can be pulled to safety in the event of

electrocution.




Inspection and Verification

1. Verify the customer concern.2. Visually inspect for obvious signs of mechanical or

electrical damage.3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to

the next step.4. If the cause is not visually evident, connect the

diagnostic tool to the data link connector and select the vehicle to be tested from the diagnostic tool menu. 5. Carry out the diagnostic tool data link test.




Brake Fluid Replacement

1. Adequate voltage to the HCU module is required during the system bleed. Connect the diagnostic tool.

2. Access the service bleed function on the diagnostic tool and follow the directions.




Service Bleeding

1. Connect the pressure bleeder to the vehicle.




2. Install rubber drain hoses to the brake bleeder screws and submerge the open ends of the hoses in clean brake fluid.3. Carrying out the service bleed function drives trapped air from the HCU. Subsequent bleeding removes the air from

the brake hydraulic system through the bleeder screws.4. Using the pressure bleeder, apply 30 psi (2 bars) of

pressure to the brake system.5. Access the service bleed function on the diagnostic

tool.6. The diagnostic tool indicates when the service bleed procedure is not followed correctly. Continue with the service bleed procedure after correcting the condition. While following the instructions on the diagnostic tool, apply the brake pedal one full stroke and then completely

release the brake pedal.




Oil Change

The Ford hybrid engine requires 4.5 quarts of oil, and Ford specifies that SAE 5W-20 oil be used. The oil change

procedure is the same as for a conventional vehicle, except be sure that the key is out of the ignition.




The A/C system battery zone is responsible for supplementing the cooling of the high-voltage battery. Cooling air is taken in from outside the vehicle and is filtered by a paper element

located in the cooling ducts.The filter can be serviced by removing a plastic cover located

on the driver’s side of the cargo area.




SUMMARY

1. The Ford Escape and Mercury Mariner hybrids share most of the same components except for trim and other non-hybrid

features.2. The Ford/Mercury hybrids are full (strong) hybrids and are capable of propelling the vehicle using battery power alone.

3. The Ford/Mercury hybrids both use an electronically controlled continuously variable transmission (eCVT).

4. The generator motor in the eCVT has three functions: generating electric current, starting the gasoline engine, and controlling the drive ratio within the transaxle to keep the gasoline engine within its most efficient speed and load

range.




SUMMARY

5. The high-voltage battery pack is located under the floor at the rear of the vehicle. The batteries are air-cooled.6. The 12-volt battery is a flooded lead-acid design and is

located under the hood.7. The Ford/Mercury hybrids use an electric power steering

system.8. Service procedures include setting up a buffer zone around

the vehicle and disabling the high-voltage circuits.9. Two fuses must be removed from the battery junction box

(BJB) before servicing the brake system. A scan tool can also be used to place the system in “Brake Pad Replacement Mode.”




REVIEW QUESTIONS

1. What are the differences between the Ford Escape hybrid and the Mercury Mariner hybrid?

2. How do the Ford/Mercury hybrids compare to other hybrid vehicles?

3. What are the features that are different about the Ford Escape and Mercury Mariner hybrids compared to the non-hybrid

version of the same vehicle?4. What safety precautions should be followed when working on

the Ford Escape and Mercury Mariner hybrids?

set up a buffer zone around the vehicle

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