What's the difference between a valve and a throttle?

Valve and throttle are not the same thing, and their functions and installation positions are also different.

Valve, also called air valve, is divided into intake valve and exhaust valve. Its function is an important control component (including gasoline engine and diesel engine) for internal combustion engine to complete four-stroke "intake, pressure, power and exhaust" working cycle. It is installed in the engine cylinder.

The throttle is what we often call the "throttle". Its function is to control the amount of mixed gas entering the cylinder. It is installed in the appropriate position of the intake manifold and connected with the accelerator pedal with a metal wire. When driving, the driver's "refueling" or "draining" actually changes the throttle opening (changing the amount of mixed gas entering the cylinder) to accelerate or decelerate the car.

It should be pointed out that gasoline engines have both valves and throttles, while diesel engines have only valves and no throttles. The change of the accelerator pedal of diesel vehicle can accelerate or decelerate the vehicle by controlling the injection quantity of high-pressure oil pump.