What does “cylinder pressure” affect during shifting?

Cylinder pressure plays a critical role in the overall performance of an engine, particularly during shifting in a manual transmission vehicle. This pressure is essentially a measure of the force exerted by the combustion gases within the cylinders. When the engine generates optimal cylinder pressure, it translates to better combustion efficiency and power delivery.

During shifting, especially when upshifting or downshifting, the engine's ability to provide sufficient power for acceleration is largely dependent on how effectively it can produce and maintain cylinder pressure. If the cylinder pressure is adequate, the engine can smoothly transition through shifts without experiencing a significant drop in power, ensuring that the vehicle accelerates smoothly and maintains performance.

In contrast, fuel economy and exhaust emissions, while affected by various factors, are more indirectly influenced by cylinder pressure relative to the immediate need for power during shifting. Several other parameters contribute to fuel efficiency and emissions, thus making them less directly related to the shifting process itself compared to the requirement for power generation. Therefore, the influence of cylinder pressure on engine power during shifting stands out as the most relevant factor in this context.