RFDiesel vs. Petrol Engine: Key Differences Explained
diesel engine
petrol engine
engine comparison
fuel efficiency
combustion
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This article breaks down the fundamental differences between diesel and petrol (gasoline) engines. Both are types of heat engines, which convert thermal energy into mechanical energy to power vehicles and machinery. Heat engines can be categorized based on the type of fuel they use, leading to classifications like diesel engines, petrol engines, and gas engines.
Let’s dive into a detailed comparison.
Diesel Engine vs. Petrol Engine: A Side-by-Side Comparison
The following table highlights the key distinctions between diesel and petrol engines:
| Feature | Diesel Engine | Petrol Engine |
|---|---|---|
| Ignition System | No carburetor, ignition coil, or spark plug. | Has a carburetor, ignition coil, and spark plug. |
| Compression Ratio | 14:1 to 22:1 | 5:1 to 8:1 |
| Fuel Used | Diesel oil | Petrol (gasoline) or power kerosene |
| Suction Stroke | Only air is sucked into the cylinder. | A mixture of fuel and air is sucked into the cylinder. |
| Fuel Delivery | Uses a fuel injection pump and injector. | No fuel injection pump or injector; utilizes a carburetor and ignition coil. |
| Ignition Process | Fuel is injected into the combustion chamber, where it ignites due to the heat of compression. | Air-fuel mixture is compressed and ignited by an electric spark. |
| Thermal Efficiency | 32% to 38% | 25% to 32% |
| Weight (per horsepower) | High | Comparatively low |
| Operating Cost | Low | High |
| Compression Pressure/Temp | 35 to 45 Kg/Cm² / about 500°C | 6 to 10 Kg/Cm² / above 260°C |
In essence, diesel engines rely on high compression to ignite the fuel, while petrol engines use a spark. This difference affects their efficiency, power output, and overall cost of operation.
