Explain why diesel engines don't use spark plugs.

diesel engines do not use spark plugs because diesel has more oil, burns slower, and is more difficult to ignite. Therefor spark plugs are insufficient with just spark so instead they use glow plugs witch provides a high amount of heat to the fuel and ignites more quickly and reliably.
The amount of compression pressure in a diesel engine is sufficient to produce enough heat to ignite the fuel. The glow plugs are only used on a cold start.

Answered by poopsie | 2024-06-10

Diesel engines don't use spark plugs because they operate on the principle of compression ignition rather than spark ignition, which is used in gasoline engines. In diesel engines, air inside the cylinder is compressed at high pressures, which increases the temperature to a level that is high enough - above the ignition temperature of the fuel. At the point of maximum compression, diesel fuel is injected into the hot, highly pressurized air, leading to spontaneous ignition.
The process of adiabatic compression raises the temperature of the air by reducing its volume, following the relationship given by the thermodynamics equation for an adiabatic process: T1 * V1^(y-1) = T2 * V2^(y-1), where 'y' is the adiabatic index. For air, y is typically 1.4. Utilizing this equation, the ratio of the initial volume V1 to the final volume V2 after compression can be calculated when the air is heated from 20 °C to 600 °C adiabatically.
Furthermore, diesel engines are known for their efficiency and the ability to use diesel filters to reduce particulate matter emissions. Alternative technologies like electric and plug-in hybrid vehicles aim at achieving zero tailpipe emissions, addressing the pollution problems posed by internal combustion engines.

Answered by JonathanAris | 2024-06-18

Diesel engines don't use spark plugs because they rely on compression ignition, which heats air to a high temperature that ignites the fuel when injected. This process differs from gasoline engines, which use spark plugs for ignition. Diesel engines typically operate with higher efficiency due to their high compression ratios.
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Answered by JonathanAris | 2024-12-24