The Use of Short-Term Compressed Air Supercharging in a Combustion Engine with Spark Ignition

Abstract

The powertrain is a very important subassembly in a car and is responsible not only for the automotive industry’s impact on the environment but also for the safety of people travelling by car and performing overtaking manoeuvres and joining traffic. In general, the powertrain is a combination of the drive unit and drive transmission, wherein the drive unit is responsible for the available driving force in the car’s wheels and for the car’s ability to accelerate when the throttle pedal is rapidly pressed at a constant gearbox ratio. The availability of the driving force reserve in the powertrain is the most important issue for the reason of safety of the people travelling by car. In the case of drive unit what they are of the combustion engines, the rapid pressing of the throttle pedal in the car acceleration process leads to a temporary deficiency in the driving force and in the powertrain’s output. The deficiency in the driving force has a negative impact on acceleration and driving comfort. In this paper, the authors assessed and analysed two different short-term compressed air supercharging systems for combustion engines with air supplied from a high-pressure tank. The analysis covered the response of the combustion engine with spark ignition to the gradual increase in pressure in the air-intake system. The assumption is that the applied short-term compressed air supercharging system could improve the driving force during the phase of the engine’s increasing crankshaft rotational speed. This helps to achieve the improved passenger car acceleration dynamics, depending on the supercharging method and throttle pedal exertion. When analysing the car’s acceleration dynamics, expressed by the shorter time of increasing the longitudinal speed from initial to final, it was possible to shorten the acceleration time. It is also possible to observe an improved driving force behaviour, especially during the first phase of acceleration.