Engine Lab Report
Diesel Engine:
- Load/N: 40, 80, 125, 171, 212, 232
- Fuel Time/s: 121.6, 94.72, 72.76, 56.95, 46.06, 41.20
- dH/mmH2O: 17.5, 17.5, 17, 17, 16.5, 17
- Speed/r. p. m: 3018, 3009, 3009, 3000, 3006, 3010
- Temp/?: 26.6, 26.7, 26.8, 26.9, 27.1, 27.2
- Air consumption/kg/H: 130.16, 130.14, 128.25, 128.23, 126.28, 128.16
- Fuel consumption/kg/H: 2.47, 3.17, 4.12, 5.72, 6.51, 7.28
- Air-fuel ratio: 52.7, 41.05, 31.13, 24.33, 19.40, 17.60
- Power/kw: 4.5, 8.97, 14.02, 19.12, 23.6, 26.03
- Efficiency/ %: 0.019, 0.059, 0.111, 0.161, 0.202, 0.216
Petrol Engine:
- Load/N: 40, 109, 160, 248, 313, 374
- Fuel Time/s: 285, 191, 160, 110.5, 93.56, 71.81
- dH/mmH2O: 2, 7, 8, 14, 20, 27
- Speed/r. p. m: 3000, 3000, 2950, 3000, 3000, 3000
- Temp/?: 26.8, 27.4, 28.2, 28.2, 28.3, 28.4
- Air consumption/kg/H: 42.50, 79.44, 84.81, 112, 145.4, 168.9
- Fuel consumption/kg/H: 3.19, 4.77, 5.69, 8.24, 9.73, 12.68
- Air-fuel ratio: 13.32, 6.65, 14.91, 13.62, 14.94, 13.32
- Power/kw: 4.47, 12.19, 17.60, 27.74, 35.01, 41.83
- Efficiency/ %: 0.014, 0.072, 0.125, 0.215, 0.290, 0.317
The air-fuel ratio of the petrol engine is constant as power increases, but it decreases for the diesel engine as power increases. The petrol engine’s air-fuel ratio is controlled by a throttle in the air intake duct, ensuring rapid combustion in the entire cylinder. In the diesel engine, combustion occurs around individual droplets of fuel spray and is related to the amount of fuel injected, so the airflow is not controlled.
Efficiency increases with power for both engines, with the diesel engine reaching higher efficiency. This is because diesel engine fuel is inputted as fuel spray, avoiding compression, leading to larger maximum cylinder volume and higher efficiency. Petrol engine should be used in light vehicles due to lighter weight and higher power, while the diesel engine is suitable for heavy vehicles due to higher efficiency.