Diesel Engine Efficiency

The Factors That Govern the Fuel Efficiency of a Diesel Engine

The diesel engine is an important component of society, and its biggest advantage over the gasoline internal combustion engine is the efficiency.
An internal combustion engine is one of the most important inventions from the Industrial Revolution. The diesel engine makes a very popular choice for many vehicles around the world. The engine efficiency refers to the rate of conversion of the thermal energy (the potential energy) into kinetic energy. The greater the efficiency, higher will be the kinetic energy produced by it, and thus, it will perform greater work.

A diesel engine works in a similar manner to the one that operates with petrol, and is powered by the ignition of small amounts of fuel. Unlike a petrol or gasoline engine, this one is not ignited by a spark plug, on the other hand, it is the heat that is produced by the compression of the fuel, which causes this ignition. A German engineer called Rudolf Diesel made this engine in 1892, and out of all the internal combustion engines, its efficiency is the highest. The reason for this is a very high compression ratio of the fuel, before it gets ignited.

A gasoline engine usually compresses the mixture at the ratio of 8:1 to 12:1, but a diesel engine's compression ratio is from 14:1 to 25:1. Also, there is no carburetor in an engine working on diesel vis-a-vis the gasoline engine. The fuel is directly and purely transported to the combustion chamber, and these engines are therefore known as Direct Injection (DI) engines.

Importance of Fuel Efficiency
The most elemental advantage of higher fuel economy is lower costs. The higher the engine efficiency, the lesser fuel will be required to do a certain type of work. This obviously works out cheaper for the user. Diesel engines used for industrial purposes require the diesel in large quantities to carry out very heavy-duty work, and even a slight increase in fuel efficiency, and a slight fall in the cost can make a large difference for the business.

In the case of vehicles using diesel engines for transportation purposes, the efficiency is calculated as a ratio of the total distance that can be covered (miles or kilometers) with a fixed amount of the fuel (per gallon or liter). The greater the distance covered, the higher is the efficiency. Various other factors of the vehicle also play a part in determining the efficiency, which are as follows:
  • Engine properties of the car.
  • Weight of the vehicle.
  • Rolling resistance of the vehicle.
  • Body drag of the vehicle.
As a result of dependency on these factors, a newer car will display higher efficiency. As the vehicle gets older and is used more often, the value keeps falling down.

Ways to Improve the Efficiency
One revolutionary way is by using ethanol mixed with water in the diesel engine. This cannot be added to the fuel directly, and hence, it cannot be used in vehicles. But, the engines that are used for other purposes, can use of this trick to get better thermal efficiency. The combination can be mixed with the diesel only at the time of combustion, and hence, two separate lines may be required. This mixture reduces emissions, cools down the engine faster, and most importantly, increases the efficiency.

The only downside with diesel powered cars is the increased amount of emissions that are produced by them. Despite this, such vehicles are quite popular, and are known to provide more miles per gallon in comparison with the regular fueled vehicles. Their cost is just marginally more than the gasoline powered alternatives.

The higher efficiency of a diesel engine certainly makes it a good choice for carrying out a multitude of jobs. Various studies and experiments are also being carried out in order to reduce the amount of harmful emissions produced by these engines. Despite these emissions, its efficiency is enough to sustain its importance and value.
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