Most diesel engines are more efficient than gasoline engines, and they can also be cleaner. One reason for their greater efficiency is their higher thermal efficiency.
This article looks at the principles and technologies that underlie a diesel engine’s ability to produce more mechanical work from the fuel’s thermal energy.
How a Diesel Engine Works?
The way a diesel engine works is quite remarkable. The diesel fuel is a petroleum-based fuel that contains three important hydrocarbons that enter the cylinder of the engine.
But first, air is pulled into the cylinder of the diesel engine and is compressed. Then the diesel fuel is sprayed into the cylinder while it is still under high pressure.
Next, an ignition will take place because of the high temperature of the cylinder while in a compressed state. This is what is called “thermal energy”, or energy that is made from the heat that is generated in the engine.
Thermal Efficiency
It is important to have this thermal efficiency in a diesel engine in order to know just how much heat is being generated by the fuel, and how much of that heat is being turned into energy.
If the engine is using most of that heat for energy, then that is a high thermal efficiency. If on the other hand there is not enough heat generated or else not enough of that heat is being turned into energy, then that is low thermal efficiency.
At this point you would have to put more diesel fuel in the cylinder of your engine so as to generate more heat, and also more energy.
So the greater the thermal efficiency in a diesel engine, the lesser the fuel consumption will be. That is why people who have vehicles with diesel engines have to pay attention to how much they are getting.
Because they eliminate so many expensive operations, diesel engines are usually found in large trucks, and the truck can run for much longer periods of time. Of all the biggest internal combustion engines, the diesels are certainly the most thermally efficient for they burn up less fuel than any comparable internal combustion engine.
This can be referred back to the diesel cycle of the engine which has a natural much greater compression ratio for generating heat. Diesel fuel also burns slower than ordinary fuel, and high compression is necessary.
Modern Diesel Engine Technology
Now thanks to new technology there are turbo-diesel engines being fitted into big vehicles that have an electronically controlled fuel injection system which further improves the thermal efficiency. At low speeds, the torque of the engine is boosted from its new turbo-charging ability.
Diesels exploit the heat that is produced more so than gasoline engines. With gasoline engines, 75% of the heat energy that is produced from the gasoline is rejected. This heat is carried away by way of the exhaust gasses coming out the tailpipe.
If a bigger vehicle used gasoline like that it would have to burn a mountain of precious juice just to create enough heat to run it. That’s why diesel engines are so much better on the thermal efficiency.