What parts did BMW valvetronic save?

Throttle, Valvetronic replaced the throttle. In 2005, BMW introduced the fourth generation M5, which is the world's first production car with a high-speed V 10 engine. More specifically, it has 10 throttles, one for each cylinder! In addition to V 10, BMW M3 E92 V8 engine uses 8 throttles.

It is also one per cylinder, and its advantage is that the fuel injection quantity of each cylinder can be accurately controlled according to the air intake of each cylinder. Disadvantages of multi-throttle, the original throttle is flawed, because when you lightly step on the throttle, the throttle is only slightly opened, but at the same time the piston moves down in an attempt to suck air from the intake pipe that is close to closing.

At this time, a vacuum will be formed between the throttle and the piston, and the external atmospheric pressure will form a great resistance to the action of the piston, which will greatly consume energy (pumping loss). The lower the engine speed, the tighter the throttle and the greater the energy loss. Therefore, BMW's Valvetronic engine cancels the throttle, especially at low speed, and the fuel saving effect after canceling the throttle is very obvious, so why does the engine without the throttle save fuel?

It also depends on BMW's Valvetronic technology! In the traditional engine, the air in the intake pipe passes through the throttle valve and then the intake valve before entering the engine cylinder. The opening and closing time of the intake valve is controlled by the timing belt and camshaft, and the opening depth of the intake valve is always fixed regardless of the speed. However, when the throttle valve is omitted in Valvetronic engine, the engine directly controls the intake air volume by electronically controlling the opening depth of the intake valve. When stepping on the accelerator, its signal is electronically transmitted to the stepper motor that controls the opening depth of the valve. After receiving the signal, the stepping motor will rotate moderately, and the opening depth of the intake valve will be changed through the transmission shaft, piston top rocker arm and tappet. The shallower the throttle is stepped on, the shallower the intake valve is opened, the deeper the throttle is stepped on and the deeper the intake valve is opened, which obviously greatly reduces the energy pumping loss.