why a diesel engine is so much more powerful than an gas engine.
In: Engineering
It mostly comes down to compression ratio differences. The much higher compression of diesel engines causes combustion to go faster and hotter, which results in higher thermodynamic efficiency and more power.
There are smaller factors, such as diesel fuel having higher energy density and diesel engines not suffering pumping losses.
The torque differences are a result of different geometry necessitated by higher compression ratios. It’s easier to raise compression ratios by lengthening the stroke length, which has the side effect of creating an engine that has greater mechanical advantage. The down side of longer stroke length is that the piston will have higher average velocity; this places a limit on engine RPM that gasoline engines usually don’t have (gasoline engines usually are limited by the valve train).
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