The inception of the diesel engine came in the late 1800s when German inventor Rudolf Diesel set out to create a more efficient alternative to gasoline and steam engines. The engine was conceived while Diesel was enrolled in engineering school and patented soon after in 1892.
While diesel and gasoline engines both operate under the same principles - converting chemical energy into mechanical energy through a series of explosions - the way these explosions occur is the primary difference between diesel and gas engines. Diesel engines do not employ a spark plug to ignite the mixture of fuel and air. Instead, the air in the engine is severely compressed and heated to temperatures in excess of 1,000 degrees Fahrenheit before being mixed with fuel. The reaction between the fuel and heated, compressed air causes an ignition, powering the engine. The higher compression ratios in diesel engines result in higher thermal efficiencies and better fuel economies.
Because pressure is the primary force needed in a diesel engine, the main components of the modern engine consists of a series of mechanical and high pressure pumps. Pump pressure is measured in a metric unit called bars. The mechanical pumps present in a diesel engine are capable of producing 200 bars, a relatively low amount. For comparison, a pistol such as the Glock 9mm being discharged produces over 2500 bars. However, the mechanical pumps have help. They work in tandem with the second component of the diesel engine, the high pressure pumps, which release 1800 bars of pressure.
The two sets of pumps work in conjunction with a series of electronic injectors, known as common rail technology, to make ignition happen. Though injectors have a simple application, they have to be able to withstand intense heat and high pressure, all while distributing fuel in the form of a fine mist. These fuel injectors can also be modified to inject fuel either before or after an engine cycle. Pre-injection reduces noise and post-injection raises the temperature of exhausted gas used in re-generating the standard diesel particulate filter.