This document discusses dual fuel engines. It begins with an introduction explaining that dual fuel engines use a gaseous fuel inducted into the engine cylinder along with air, and a small amount of diesel fuel is injected as a pilot fuel to ignite the air-gas mixture. It then discusses factors that affect combustion in dual fuel engines like pilot fuel quantity and injection timing. The document outlines advantages of dual fuel engines such as reduced emissions and lower operating costs compared to diesel or natural gas engines. It concludes that dual fuel engines can substitute up to 70% of diesel fuel with a gaseous fuel like natural gas.

1. K .Rajkumar
18285A0302

2. 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

3. 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. .

4. 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
What is DUAL FUEL ENGINE?

5. 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

6. THE WORKING PRINCIPLE
Dual fuel Engine Working

7. 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

8. 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

9. 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 OF THE FOOLOWING METHODS:-
• Excess supply of air.
• Use of cold combustion air.
• Increased cooling of piston.
• Reducing the pressure of the gaseous fuel.

10. • Advantage of Dual- fuel Engine
The dual fuel engine has the following advantages:
• The gas burns without leaving any residue - exhaust is clean –
less air pollution.
• The clean combustion results in reduced wear of the engine
parts and reduced consumption of lubricating oil. The
lubricating oil change periods are also increased as the
maximum pressure in cylinder are less than those for a diesel
engine, thereby reducing the blow-by past piston. This reduces
the contamination of the lube oil.
• 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

11. 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