chapter 1 (alternative fuels)

8/9/2019 Chapter 1 (Alternative Fuels)

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ALTERNATIVE

FUELS

CHAPTER :


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1. Alternative fuel classification and

application

Types of alternative fuel

The importance of alternative fuel

Advantages and disadvantages among

various alternative fuel


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2. The function, construction and operation of

Natural Gas Vehicle

Components name, function and operation of NGVsystem

Schematic diagram of NGV system circuit

Operation of an NGV system

Components name, function and operation of NGV

system

Advantages and disadvantages of using NGV asalternative fuel


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Alternative fuels are derived fromresources other than petroleum

Some are produced domestically,reducing our dependence onimported oil and some are derivedfrom renewable sources

Produce less pollution thangasoline or diesel.


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IC Engine obtain from combustion ofhydrocarbon fuel with air - convertschemical energy (fuel) to internalenergy in the gases within the engine

Main fuel for SI engines - GASOLINE

*SI (spark ignition) start thecombustion process & spark plug

gives high voltage which ignites theair-fuel mixture in combustionchamber


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ETHANOL

- produced domestically from corn and other crops

- produces less greenhouse gas emissions thanconventional fuels

BIODIESEL

- derived from vegetable oils and animal fats

- produces less air pollutants than petroleum-baseddiesel

PROPANE

-

called liquefied petroleum gas (LPG)- domestically abundant fossil fuel that generates less

harmful air pollutants and greenhouse gases

- Mainly of methane (60 98%) with small amount ofhydrocarbon


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HYDROGEN

- produced domestically from fossil fuels (such as coal),

nuclear power, or renewable resources, such ashydropower

- Fuel cell vehicles powered by pure hydrogen emit noharmful air pollutants

NATURAL GAS

- fossil fuel that generates less air pollutants and

greenhouse gases


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Concern over the emission problems ofgasoline engines

To improve major contributor to the airquantity problem

Made in reducing emission systems Research to reduce air pollution problem


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ADVANTAGES

DISADVANTAGES

More efficiently by using

higher compression ratio

Low energy content of the

fuel

Lower overall emissionscompared with those of

gasoline

much more corrosive thangasoline alcohol can cracked

metal in engine

When burned, it gives higherpressure and more power in

the expansion stroke

Poor ignition characteristics ingeneral

Low sulfur content in the fuel Poor cold weather startingcharacteristics due to lowpressure & evaporation


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ADVANTAGES

DISADVANTAGES

Domestically produced from non-petroleum, renewable resources

Use of blends above B5 not yetapproved by many auto makers

Can be used in most diesel engines,especially newer ones

Lower fuel economy and power (10%lower for B100, 2% for B20)

Less air pollutants (other than nitrogen

oxides)

Currently more expensive

Less greenhouse gas emissions (e.g.,B20 reduces CO2 by 15%)

Slight increase in nitrogen oxideemissions possible in somecircumstances

Biodegradable generally not suitable for use in low

temperatures

Non-toxic & Safer to handle

More efficiently by using highercompression ratio


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ADVANTAGES

DISADVANTAGES

90% of propane used in U.S.comes from domesticsources

Limited availability

Less expensive than

gasoline

Less readily available than

gasoline & diesel

Potentially lower toxic,carbon dioxide (CO2),carbon monoxide (CO) and

emissions

Fewer miles on a tank offuel

High octane number makefor high thermal efficiency


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ADVANTAGES

DISADVANTAGES

Environmentally Friendly Fuel Cost & Availability

Hydrogen produces no airpollutants or greenhousegases when used in fuelcells

Vehicle Cost & Availability- Fuel cell vehicles arecurrently too expensive

Produces only nitrogenoxides (NOx) when burnedin ICEs

Onboard Fuel Storage- storage systems do not yetmeet size, weight, and costgoals for commercialization

Hydrogen contains muchless energy than gasoline ordiesel on a per-volume


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ADVANTAGES DISADVANTAGES

Engine can operate with a high

compression ratio - good forsingle throttle body fuel injector

Low energy density resulting in

low engine performance

Low engine emissions Refueling is slow process

6090% less smoke -producingpollutants

Inconsistent fuel properties

3040% less greenhouse gasemissions

Need to large pressurized fuelstorage tank

Less expensive than gasoline Limited vehicle availability

Less readily available thangasoline and diesel

Fewer miles on a tank of fuel


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Natural gas vehicle(NGV)

compressed natural gas (CNG) liquid natural gas (LNG)

As a clean alternative to other automobilefuels

NGV or methane is the lightest hydrocarbon

Methane is a by-product of decomposing

organic matter including the rotting of deadplants, garbage dumps as well livestockmanure.


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CNG LNG

stored on the vehicle inhigh-pressure tanks -20 to 25 MPa (200 to

250 bar, or 3,000 to3,600 psi)

contains hydrocarbonssuch as ethane &propane as well as othergases such as nitrogen,helium, carbon dioxide,sulphur compounds,

and water vapour

stored as a super-cooled(cryogenic) liquidbetween -120 & -170C

(-184 & 274F)

that it offers an energydensity comparable topetrol and diesel fuels,

extending range &reducing refuellingfrequency


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Dedicated: These vehicles are designed to run

only on natural gas

Bi-fuel: These vehicles have two separatefueling systems that enable them to run on

either natural gas or gasoline

Dual-fuel: These vehicles are traditionallylimited to heavy-duty applications, have fuelsystems that run on natural gas, and usediesel fuel for ignition assistance


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Typical NGV Vehicle System


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Compressed natural gas (CNG)tank

CNG tank can be made of steel,aluminum, or plastic

Lightweight composite - weightreductions when compared with earliergeneration steel and aluminumcylinders, which leads to lower fuel

consumption

Mixer

Mechanical devices that by using theVenturi principles

Ensure correct air/fuel mixture in bothstationary and dynamic conditions

Each mixer is designed for a specificvehicle in order to optimize both gasand petrol operation


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Manometer/Pressure Gauge

It is shows the pressure or level of contents of theNGV cylinder from full to empty

Internal fuel gauge is installed on the dashboardin a lightly visible position

High Pressure Pipe

Fuel lines running between the storage cylinderand the pressure regulator are made of highstrength steel

They are usually installed along the frame of the

car for better protection


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Bi-fuel Selector Switch

Gas/petrol selector with 3 positions andfuel consumptions indicators with 2 LED

Manual (push button) gas starting systemto enrich the mixture for starting(primer); the middle position of the switchcloses the gas and petrol solenoid valvesat the same time

Regulator/Reducer

Reduce the pressure of the stored gas inthe cylinder and regulates the flow to theair-fuel mixer

Gas flow rate from regulator variesaccording to the strength of the signalfrom the mixer


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Power Valve

This device positioned between regulatorgas outlet and the mixer to control theoptimum gas flow from regulator tomixer.

Refueling Valve

Install in engine compartment betweentank and regulator includes connection to

the refueling system

It is fitted with a non-return valve toprevent of gas loss


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- Natural gas is compressed and enters thevehicle through the natural gas fill valve(receptacle)

- It flows into high-pressure cylinders located

in or under the vehicle

-Fuel selector on the dashboard permitsselection of natural gas or gasoline to act as

the fuel for the vehicle


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- When natural gas is needed by the engine, itleaves the cylinders and passes through the

master manual shut-off valve

- The gas goes through the high-pressure fuelline and enters the engine compartment.

- Gas enters the regulator, which reducespressure from up to 3,600 psi to near

atmospheric pressure.


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- The natural gas solenoid valve allows naturalgas to pass from the regulator into the gasmixer or natural gas fuel injectors. (it shuts

off the natural gas when the engine is notrunning)

- In a bi-fuel NGV, natural gas mixed with air

flows down through the gasoline carburetoror fuel injection system and enters theengines combustion chambers


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NGV FOR LIGHT DUTY VEHICLE

1. Fumigation System Sistem Pengewasapan)

The important component for this system is agas mixer

It functions as a mixer of air and NGV at the

precise rate for the right combustion beforetransmission to the engine

This system is suitable for a carburetorengine

There are two separated gas transmittingregulation systems


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Open - Loop System

This system is the same as the LPG systeminstalled in taxis. There is no electronic controlunit (ECU)

Closed- Loop System

This system is installed as an electric controlunit (ECU) to regulate the right amount of fuelemission


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2. Multi Point Injection System or MPI

An ECU is used to evaluate the mass flow ofgas before transmitting it to the combustionchamber

This system is good engine fuel injectionsystem (EFI)


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NGV FOR HEAVY DUTY VEHICLE

1. Diesel Dual Fuel System DDF)

This system has been designed to run only ondiesel or on both

The ratio of NGV gas and diesel fuel depends

on the engine itself and the quality of theCNG equipment used

The advantage of this system, vehicle canoperate on diesel or on both by using a

selection switch There are two separate systems for emission

regulation


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2. Re-powering

For re-powering, an existing diesel engine isremoved and replaced with a benzene engine

After that, NGV bi-fuel system equipment isinstalled


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Emissions are cleaner less wasted fuel

lower emissions of carbon

lower particulate emissions per equivalentdistance travelled

Substantial savings (50%) in fuel cost

Lower operating cost


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high price for installation High maintenance - expensive to design and

build

use the maximum space - give up preciouscargo and trunk space to accommodate thefuel storage cylinders

might be harder to find than a "regular" gas

station fossil fuel and cannot be considered a

renewable resource


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Reducer

It drops the gas pressure from 220 bar to 1.8 bar. Thiscomponent uses a diaphragm. It needs to be serviced and thediaphragm replaced at regular intervals

The Gas Injectors

Use multiple gas injectors with one injector for each port. Thereparts will wear out and leak, and have to be replaced

Gas ECU

ECU are supposed to last the life of the vehicle, they can fail atany time.

Aft 5 000 kil t ti i filt


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After every 5,000 kilometers operation, air filtersshould be checked and cleaned

Seat exhaust valve should be inspected and resetbecause the corrosion of seat exhaust valve ofNGV faster than gasoline

Using hardened valve seats - NGV is a dry fueland lacks the lubricating properties of a liquidfuel

Weight problem (increasing tank & component)- Effect on the rear suspension & braking

chapter 1 (alternative fuels)

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