4. What's the difference between the throttle opening at startup, normal load and heavy load?

1. When starting: When the engine is started, the throttle valve is usually closed or nearly closed. This is because the engine needs higher cylinder pressure to push the piston when starting, and then start the engine. Therefore, closing the throttle can reduce the air intake and improve the success rate of starting.

2. Under normal load: When the engine is under normal load, the throttle opening will be adjusted according to the driver's demand and the driving state of the vehicle. In a stable driving state, the throttle valve will maintain a relatively stable opening to meet the working requirements of the engine. The throttle opening is usually adjusted according to the running speed and load of the vehicle.