Eli5: Why are petrol engines not built like diesel engines in terms of reliability?

Question

Diesel engines easily run 400.000km especially Mercedes cars but petrol will give up way sooner

In: Engineering

Answer 1

It’s not as easy as saying “diesel engines are more reliable than gasoline engines”.

There are plenty of ultra reliable gasoline engines that will run virtually forever with nothing more than basic maintenance. Just like there are plenty of diesel engines that are absolute garbage for reliability.

I think some of the bias in favor of diesel is that it tends to be the fuel of choice for heavy duty applications where long term reliability is more important than other applications where an engine is used. For example big trucks for transporting goods tend to accumulate a lot more miles than a personal car so the engines are designed to be more robust, which also makes them more expensive upfront. That upfront cost is worth it for the application but it’s not in a personal vehicle.