WHAT IS A MULTI-FUEL ENGINE ?

A MULTI-FUEL ENGINE ONE WHICH WOULD

OPERATE SATISFACTORILY WITH

SUBSTANTIALLY UNCHANGED

PERFORMANCE AND EFFICIENCY, ON A WIDE

VARIETY OF FUELS RANGING FROM DIESEL

OIL, CRUDE OIL TO LIGHTER FUELS LIKE

GASOLINE AND EVEN NORMAL LUBRICATING

OIL.

GENERALLY A C.I. ENGINE IS PRFFERED FOR

THIS PURPOSE.

WHY USE A C.I. ENGINE ?

ALMOST ALL DIESEL ENGINES ARE CAPABLE

OF BURNING A WIDE VARIETY OF FUELS.

THE USE OF LOW IGNITION QUALITY FUELS

REQUIRES A HIGHER COMPRESSION RATIO

FOR SATISFACTORY BURNING.

DUE TO THIS REASON A C.I. ENGINE IS

PREFFERED AS RAISING THE COMPRESSION

RATIO IN S.I. ENGINES IS A VERY DIFFICULT

JOB.

QUALITIES A MULTI-FUEL ENGINE

MUST POSSESS

IT MUST HAVE A GOOD COMBUSTION EFFICIENCY.

THE TEMPERATURE OF THE COMBUSTION CHAMBER MUST BE COMPARITIVELY HIGHER.

THE ENGINE MUST BE CAPABLE OF STARTING UNDER SUB-ZERO CONDITIONS WITHOUT ANY EXTERNAL AID.

THE ENGINE MUST HAVE LOW EXHAUST SMOKE AND LOW NOISE LEVEL.

DESIGN FEATURES ESSENTIAL

FOR MULTI-FUEL OPERATION

HIGHER COMPRESSION RATIO

HIGHER STROKE/BORE RATIO

COMBUSTION CHAMBER DESIGN:

a)OPEN COMBUSTION CHAMBER

b)SPHERICAL COMBUSTION CHAMBER

c)M-TYPE COMBUSTION CHAMBER

INJECTION PUMP

COMBUSTION CHAMBER OF A G.M. MULTI-

FUEL ENGINE

PERFORMANCE OF MULTI-FUEL ENGINES

ADVANTAGES

CAN OPERATE ON A WIDE VARIETY

OF FUEL.

CAN BE STARTED UNDER SUB-ZERO

CONDITIONS.

LOW EXHAUST SMOKE.

LOW NOISE LEVEL.

LIMITATIONS

TENDENCY OF VAPOUR LOCK IN THE FUEL PUMP WHILE USING LIGHTER FUELS.

TENDENCY OF INCREASED WEAR IN FUEL PUMPS.

REQUIREMENT OF INJETING DIFFERENT VOLUMES OF FUELS DUE TO DIFFERENCES IN THEIR HEATIND VALUES AND COMPRESSIBLITY.

MODIFICATON OF FUEL SYSTEM

VAPOUR LOCK

LUBRICATION

VARIATION IN CAPACITY

JACKET WATER HEATING

FLAME HEATER

TURBOCHARGING

TYPICAL FUEL RACK STOP

FUEL INJECTOR

MILITARY MULTI-FUEL ENGINES

One common use of this technology is in thedrive of military vehicles, so that they may runa wide range of alternative fuels such asgasoline or aviation (gas turbine) fuel. This isseen as desirable in a military setting asenemy action or unit isolation may limit theavailable fuel supply, and conversely enemyfuel sources, or civilian sources, may becomeavailable for usage. Currently a wide range ofRussian military vehicles employ multi-fuelengines, such as the T-72 tank (multi-fueldiesel) and the T-80 (multi-fuel gas turbine).

T-72 TANK

BI-FUEL VEHICLES

Bi-fuel vehicles are vehicles with multi-fuel engines capable of running on two fuels. On internal combustion engines one fuel is gasoline or diesel, and the other is an alternate fuel such as natural gas (CNG), LPG, or hydrogen. The two fuels are stored in separate tanks and the engine runs on one fuel at a time, unlike flexible-fuel vehicles ("dual-fuel"), that store the two different fuels mixed together in the same tank, and the resulting blend is burned in the combustion chamber. Bi-fuel vehicles have the capability to switch back and forth from gasoline or diesel to the other fuel, manually or automatically.

A BI-FUEL VEHICLE

FLEX-FUEL VEHICLES

FACTORY BI-FUEL PASSENGER

CARS

Fiat Punto

Fiat Siena Tetra fuel, with a gasoline flex-fuel engine and natural gas (CNG).

Holden Commodore dual-fuel (LPG/petrol)

Chevrolet Cavalier

Ford Contour

Mazda RX-8 Hydrogen RE

Premacy Hydrogen RE Hybrid

Chevrolet SPARK Bi-Fuel

VW Polo Bi-Fuel

FUEL DENSITY COMPENSATOR

The multi-fuel engine operates on a variety of fuels that have a broad range of viscosities and heat values. These variations in the fuels affect engine output. Because it is unacceptable for the power output of the engine to vary with fuel changes, the multi-fuel engine is fitted with a device known as a fuel density compensator . The fuel density compensator is a device that serves to vary the quantity of fuel injected to the engine by regulating the full-load stop of the fuel pump. The characteristics of the fuels show that their heat values decrease almost inversely proportional to their viscosities. The fuel density compensator uses viscosity as the indicator for regulating fuel flow.

REFERENCES

A COURSE IN I.C. ENGINES –

MATHUR & KHANNA

WIKIPEDIA

GOOGLE IMAGES

PRESENTED BY

ARPIT & SHREYAS PRAKASH

UNDER THE GUIDANCE OF DR.

RAJAGOPAL.