Thermal efficiency refers to thermal energy and thermal energy refers to the chemical energy of a fuel converted to thermal energy through combustion. Thermal efficiency is total available thermal energy as opposed to thermal energy used to perform work.elixer akm said:What is the difference between thermal efficiency and mechanical efficiency of engine...and which engine is more efficient ..petrol or diesel
Thermal efficiency refers to the amount of heat energy that is converted into mechanical work, while mechanical efficiency is the measure of how well an engine can convert mechanical work into output power.
Petrol engines have a higher thermal efficiency due to their higher compression ratio, which allows for more complete combustion of fuel. Additionally, petrol engines have lower friction losses, resulting in higher mechanical efficiency.
Diesel engines have a higher torque output at lower RPMs, making them better suited for heavy loads. They also have a longer lifespan and require less maintenance compared to petrol engines.
A higher thermal efficiency means that less fuel is needed to produce the same amount of power, resulting in lower fuel consumption. Similarly, a higher mechanical efficiency means that less energy is lost to friction, also leading to lower fuel consumption.
Advancements in fuel injection, turbocharging, and hybrid technology have all contributed to improving the efficiency of both petrol and diesel engines. Additionally, improvements in engine design and materials have also played a role in increasing efficiency.