A Brief about the Modern Diesel Engine

Named after Rudolf Diesel, the diesel engine is an internal combustion engine in which the ignition of the fuel is caused by the elevated temperature of the air in the cylinder that occurs due to mechanical combustion - also known as adiabatic compression.

The diesel engine is also known as a compression-ignition or CI engine and is in contrast with the spark-ignition engines in which a spark plug is used to ignite an air-fuel mixture. In a diesel engine, the compression increases the air temperature inside the cylinder to a high degree which in turn helps in a spontaneous ignition of the atomised diesel fuel that is injected into the combustion chamber.

For quite some time now, the top automobile manufacturer Maruti Suzuki's diesel engine cars that are designed with advanced features and specifications, for example, Maruti Suzuki cars with the DDiS diesel engine have managed to capture the attention of several car buyers in recent times. The diesel engine has one of the highest thermal efficiency due to its high expansion ratio and inherent lean burn that helps in heat dissipation by excess air. Here, a small amount of efficiency loss is avoided as unburned fuel is not present in the valve overlap.

Operating Principle behind a Diesel Engine

The characteristics of a diesel engine include –

Compression ignition: As mentioned before, because of the adiabatic compression, the fuel in a diesel engine car gets ignited without any external ignition gear like spark plugs. Also, the air and fuel are mixed in the combustion chamber.

Engine speed adjustment solely by mixture quality: Here, the torque produced, which results in the crankshaft rotation speed difference, is set by the mass of injected fuel rather than the throttling of the air-mixture.

High air ratio: Since a diesel engine mainly runs on air and not on the exact air-fuel mixture, they have a leaner and better ratio.

Fuel with high ignition performance: A diesel engine depends on the compression ignition and hence fuel with high ignition performance is more suitable for the best engine operation.

The diesel engine has undergone many advancements in recent times and diesel engine cars too have gained a lot of popularity.