Diesel engines and petrol engines have several key differences. Diesel fuel is more dense and viscous than petrol fuel and has a lower self-ignition temperature. Diesel engines are heavier, larger, and more durable than petrol engines. They have higher compression ratios and thermal efficiencies up to 40%, producing more power and torque than petrol engines. While diesel engines are more fuel efficient, they are more expensive initially and have higher maintenance costs than petrol engines.

2. Difference Between 4-stroke Diesel
Engine and 4-stroke Petrol Engine
By Muhammad Shafaat (14ME30)

3. Diesel Petrol
 Made from Petroleum/ Crude oil
 More dense and more viscose
 Self ignition temperature is low
 Made from Petroleum/ Crude oil
 Less dense and less viscose
 Self ignition temperature is high

4. Petrol Engine Diesel Engine

5. Petrol Engine Diesel Engine

6. Differences between Diesel Engine and Petrol
Engine On the basis of Structure
Petrol Engine Diesel Engine
Spark Plug is used Employs an injector.
Occupies less space Occupies more space
Light in weight Heavy in weight
Smaller in size Bigger in size

7. Differences between Diesel Engine and Petrol
Engine On the basis of Performance
Petrol Engine Diesel Engine
Thermal efficiency up to 25% Thermal efficiency up to 40%
Has lower Compression Ratio Has higher Compression Ratio
Produce less Power Produce more Power
Produce high RPM Produce low RPM
Produce low Torque Produce high Torque
Fast Acceleration Slow Acceleration
Are less Durable Are more Durable

8. Differences between Diesel Engine and Petrol
Engine On the basis of Environmental Effect
Petrol Engine Diesel Engine
Produce low Vibrations Produce high Vibrations
Produce low Noise Produce high Noise
Produce more CO2 Emission Produce less CO2 Emission

9. Differences between Diesel Engine and Petrol
Engine On the basis of Economy
Petrol Engine Diesel Engine
Lower in Price Expensive in Price
Lower Maintenance Cost Higher Maintenance Cost
Less Fuel Efficient More Fuel Efficient

10. Some Applications
 High Speed Vehicles
Petrol Engine Diesel Engine
 High Power Vehicles

11. Thank You