Why does a petrol engine have more power than diesel engine?

It's actually not true that a petrol engine has more power than a diesel engine. In fact, diesel engines are known for producing more power and torque than petrol engines, especially at low RPM ranges. This is because diesel engines have a higher compression ratio, which allows them to generate more power from the same amount of fuel. Additionally, diesel fuel has a higher energy density than petrol, meaning that it produces more energy per unit of volume. Therefore, diesel engines are more efficient and produce more power than petrol engines of similar size.