preheating of fuel

Topics: Internal combustion engine, Diesel engine, Combustion Pages: 13 (2565 words) Published: April 14, 2014
Pre-heating Fuel for Charge Homogeneity
to Improve Combustion

Abstract – The idea of the automobile engine that people
have is of one that is bygone. The automobile engine today is the pinnacle of engineering expertise, implementing the best of technologies and undergoing the best of manufacturing
processes to make the closest possible achievement to
perfection, from design to combustion. The art of perfection though starts much before the process itself. In case of the automobile engine, the process is the 4-Stroke cycle that most engines go through and the art we are referring to is

attaining homogeneity in charge. Homogeneous charge in
an Internal Combustion Engine refers to the complete
mixture of fuel (Petrol) and air, entering the cylinder. Ideally this would mean the complete dispersion of the atomised fuel in air. This as a result reduces the overall efficiency of the engine. To help achieve the required atomisation, reducing

the Surface Tension of the fuel is a potential solution. On
reduction of Surface Tension the atomisation is enhanced,
possibly reaching the ideal value. This can be achieved by
heating the fuel to an operating temperature for which heat
can be extracted from a potential source, namely the Exhaust Manifold.

A. By-products are formed in the form of smog as a
result of supplementary reactions such as NOx or
the various oxides of nitrogen, the nature of these
reactions is endothermic, higher the temperature,
greater the emissions of NOx
N2 + O2 --> 2 NO (Δh = 175.728kJ)
½N2 + O2 --‐--‐> NO2 (Δh = 33.9kJ)
B. Incomplete combustion resulting in the formation of
CO or carbon monoxide a highly poisonous and
good oxidizing agent. The formation of CO is
favoured at lower temperatures contrary to NOx
H-C + ½O2 --> CO + ½H2O (Δh = -110.527kJ*)
C. Some hydrocarbons are not burnt due to lack of
successive collisions between oxygen and fuel.
D. Based on our reading, observation and calculation,
we have the following tables

Keywords – Pre-heating, Homogeneity, Internal Combustion
Engine, Atomised fuel, Surface Tension, Exhaust Manifold.

I.

INTRODUCTION

Energy demands are rising in contrast to its scarcity
and rapid depletion. Alternate sources render current
infrastructure worth trillions obsolete, disconnecting
decades of development. We propose a hypothesis for
enhancing the utility of petrol, a major source of energy
in sectors of transportation.

Table 1 : Major components in combustion [16,17,18]

The fuel petrol is a mixture of over 200 species of
hydrocarbons H-C averaging a molecular weight
105g/mol. based on stoichiometry, 1 part of fuel
requires 14 parts of air for complete combustion and
liberates CO2 and H2O as the only by-products.

*The negative sign is to indicate that energy is absorbed, thereby inhibiting an equivalent amount of already produced power

2H-C + O2 + N2 --> H2O + CO2 + N2 + H-C

Table 2: Degree of concern [16,17,18]

However in a real engine,

ISSN : 2319 – 3182, Volume-2, Issue-1, 2013

87

International Journal on Theoretical and Applied Research in Mechanical Engineering (IJTARME)

Burning 1m3 petrol at STP releases 33,600,000kJ of
heat, the combined losses contribute to a total of
4,061,512.5kJ to be subtracted from the output, which is
12.08% of the total heat this equals 83.4kg worth petrol.
The unused energy alone totals 3950804kJ, which is
11.75% of the total input.

II. SYSTEM SETUP
Since the fuel (petrol) needs preheating, small and
affordable modifications to the already existing systems
need to be made. This is such that today’s automobile
system design undergoes no major change. A diagram
describing this system design is shown as follows.

In most modern vehicle engines, fuel is injected
into the cylinder towards the end of the compression
stroke. More efficient engines have combustion chamber
characteristics to facilitate excellent turbulence and
swirl for thorough mixing of...
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