This is why there is the need for a spark plug that causes the explosion that is necessary. The diesel however requires no spark plug and will ignite when compressed.

Diesel engines therefore have much higher compression pressures than the gasoline engines. This difference is due to the fact that air alone is compressed in the diesel engine and therefore the fuel goes directly into the cylinder and allows the compression ratio to be much higher.

It is seen that the fuels also differ in the amount of carbon and hydrogen atoms. The diesel fuel has more carbon and hydrogen atoms than the gasoline making it more energy dense than the gasoline and therefore providing more energy per gallon when compared to gasoline.

In terms of Heat pump Brazed Plate Heat Exchangers efficiency it can be seen that the two engine types vary significantly from one another. It can be argued that the diesel engine is the more efficient of the two engine types. There are however some drawbacks to the diesel engine in terms of environmental issues as well as noise.