Overview of Presentation
• Introduction
• Working Principle.
• Dual-Fuel Operation
• Factors Affecting Performance in Dual-
Fuel Engine.
• Performance of Dual-Fuel Engine
• Advantages of Dual-Fuel Engine 1
Introduction to Dual Fuel Engine
The dual-fuel engine works on diesel cycle. The gaseous fuel (the primary
fuel) is added to the air inducted by the engine or supplied by the
supercharger at a pressure slightly above the atmospheric pressure. This
mixture of air and gaseous fuel is compressed in the cylinder just like air
in normal diesel operation. At some point in the compression stroke, near
top dead center, a small charge of liquid fuel called pilot fuel (or the
secondary fuel) is injected through a conventional diesel fuel system. This
pilot acts as a source of ignition the gas-air mixture in the vicinity of the
injected spray ignites at a number of flame-fronts. Thus combustion stars
smoothly and rapidly. .
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What is DUAL FUEL
ENGINE?
In CI engine, gaseous fuel (secondary fuel) is inducted and compressed in the
engine cylinder with air, and a small quantity of diesel ( Pilot fuel- primary fuel) is
injected through the conventional diesel fuel system to ignite the mixture
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Why Dual fuel engine required ?
• The shortage of liquid fuel and the realization that gaseous
fuels are far cheaper than liquid fuels have led to attention
on dual-fuel engine.
• natural gas available to most of part of the world at
rates cheaper than liquid fuels
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Dual fuel Engine Working
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Dual-Fuel Operation
Dual-fuel operation is
achieved by the
burning of both a
gaseous fuel and
diesel at the same time
in a CI engine
Injection of small
amount of diesel fuel can
be used as an ignition
source
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FACTORS AFFECTING COMBUSTION
IN A DUAL-FUEL ENGINE
1. Pilot fuel quantity
2. Injection Timing.
3. Cetane Number of Pilot Fuel.
4. Inlet Temperature.
5. Gaseous Fuels.
6. Effect of Throttling.
7. Mixture Strength
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KNOCK AND ITS CONTROL IN DUAL-FUEL
ENGINE
NATURE OF KNOCK: - The phenomenon of knock in a
dual-fuel engine is of the nature of auto ignition of
gaseous mixture in the neighborhood of injected
spray.
KNOCK IN DUAL-FUEL ENGINE CONTROLLED
BY ANY OFTHE FOLLOWING METHODS:-
• Excess supply of air.
• Use of cold combustion air.
• Increased cooling of piston.
• Reducing the pressure of the gaseous fuel. 8
Advantage of Dual- fuel
The dual fuel engine has the following
Engine
advantages:
• The gas burns without leaving any residue - exhaust is clean
– less air pollution.
• Lower initial cost and lower operating costs than a
dedicated natural gas engine
• Better fuel economy than a dedicated natural gas engine
• Lower maintenance costs than a dedicated natural gas
engine
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CONCLUSION
The ignition delay in gas-fueled diesel engines of
the dual-fuel type depends strongly on both the
quantity and quality of the pilot fuel used.
Dual-fuel engine performance is improved with the
employment of high cetane number pilots.
For stationary application, diesel substitution of 70%
is possible by using dual fuel engine which is quite
considerable and also economical
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