Last Updated on 22 July 2024 by automobilehut.in
CNG car performance depends on the various factors relay to the car’s condition and features. Since CNG is a gaseous fuel, the storage capacity for CNG in a vehicle is comparatively less than that of petrol. Let’s talk about the chapter.
CNG Car Performance
It has been experienced that a petrol engine will produce less power on CNG than on petrol and motorists may feel that a car’s performance on CNG is inferior. The questions usually asked are: why and how much?
It is necessary to consider three separate aspects that can contribute to the performance and power difference. Careful maintenance and driving practices are, therefore, prerequisites for the success of the CNG vehicle. Petrol vehicles converted to natural gas are subject to a small power loss when running on natural gas, however, vehicles designed specifically to run natural gas will have no loss of power and may even have greater power and efficiency. These factors are-
Fuel Related Factors
The space occupied in the engine cylinder by CNG is greater than that occupied by petrol, with the result that the fuel-air mixture inside the engine cylinder contains 8-10% less air(oxygen) in CNG mode. Less oxygen means less fuel burnt and hence power produced. Since CNG burns more slowly than petrol, it produces less power and slower idle speed for the same ignition timing and throttle position.
The difference in the burning rate can be partially compensated by advancing the ignition for CNG. Idling, rpm also needed to be increased in the CNG mode to prevent engine stalling. Natural gas also requires a much higher ignition temperature to burn in the combustion cylinder. Differences in available energy are combustion characteristics between petrol and natural gas and may persist under any condition and are considered unavoidable, even with optimized ignition timing, unrestricted airflow, etc.
Petrol Engine-Related Factors
The power output also depends on individual engine design features, particularly in the engine combustion chamber, valve timing, inlet manifold heating, and positioning of the air cleaner intake. In most petrol engines, the air cleaner draws hot air from immediately behind the radiator or in the vicinity of the exhaust manifold. This heating of charge affects the power output of the engine.
CNG Conversion System-Related Factors
A major factor in the optimal performance of the conversion kit is the quality of kit installation by the workshops. Optimization of the gas mixture ignition timing and spark strength during installation is necessary to get acceptable power performance.
If components such as power valves and elbows in the low-pressure hose have sharp bends or extra length, or if any restriction in the gas flow is caused due to flattened tubing or other obstructions, the gas flow will vary, causing uneven engine output.
The design and fitment of the gas mixture may also cause an uneven airflow-thereby reducing the volume of air.
Conclusion
Factors such as low compression pressures, dirty air cleaner elements, wrong spark plug gaps, etc. can cause starting/idling problems and engine overheating while on CNG.
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