Download - Multi-Fuel Engines
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.