Why are diesel car engines so much louder than petrol, they sound like tractors?
In: Engineering
1 bar is atmospheric pressure. Remove the air from a steel oil drum – 1 bar is plenty enough to crush it.
In petrol cars the explosion in the cylinder reaches about 20 bar under low load, and about 70 bar full load.
In diesel engines the pressure explosion would be around 80 bar at light load, and potentially almost 200 bar at full load. This higher pressure makes the characteristic loud chugging sound.
Also the fuel injectors which work at a crazy 2000 bar (!) make a characteristic clicking sound each time they inject fuel. This makes the characteristic click.
Also tractor engines are generally diesel.
Incidentally lots of small, compact European diesels aren’t particularly loud nowadays since they are very effectively isolated and shielded.
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