Electronic valve technology

BMW's six-cylinder power plant is not only lighter than all competitors' products, but also provides excellent output power and performance. This is largely due to BMW's unique fully variable Valvetronic electronic valve control, which can stepless adjust the valve opening according to the accelerator pedal position and control the time.

In traditional engines, the control of output power depends almost entirely on the intake throttle. Throttle? To achieve this, some strength will inevitably be lost in the process. In contrast, Valvetronic electronic valve control technology can minimize engine load changes and cycle management requirements, thus ensuring extremely high fuel efficiency and better engine response speed. Other advantages include improving engine running smoothness and reducing exhaust emissions.

The BMW inline 6-cylinder power plant with magnesium-aluminum alloy crankcase and the second-generation BMWValvetronic electronic valve have achieved higher engine speed through the more compact structure of the whole system. Therefore, faster acceleration is ensured by the operation of the valve, so that the driver can get faster response when stepping on the accelerator pedal, and a larger speed reserve is formed in each gear.

On gasoline engines, BMW's Valvetronic technology can be said to be the best variable valve technology today.

Technical principle:

BMW's engine with Valvetronic technology is the first engine without throttle in the world.

Throttle? It is an air valve in the engine intake manifold that looks like a butterfly.

So what are the benefits of reducing the throttle? This advantage is fuel saving. Various test results show that compared with the traditional engine, Valvetronic engine can save more than 7% fuel consumption. To understand why an engine without a throttle can save fuel, we must first understand how the throttle of a traditional engine works. When you step on the gas pedal to refuel, you may feel that the engine is refueled, but actually stepping on the gas pedal does not directly increase the fuel injection quantity of the engine cylinder, but changes the size of the throttle switch of the intake pipe, thus changing the air quantity entering the cylinder. The fuel injection system of the automobile monitors the air quantity passing through the throttle valve to decide how much oil to inject. This is how the throttle controls the engine. The main purpose of this design is to hope that the oil-gas mixture ratio will not change under different throttle opening, so as not to cause flameout.

So why does an engine without a throttle save fuel? When you lightly step on the accelerator, the throttle valve only slightly opens, but at the same time, the piston moves down, trying to suck air from the closed intake pipe. At this time, a vacuum will be formed between the throttle valve and the piston, and the external atmospheric pressure will form a great resistance to the action of the piston, which will greatly consume energy. The lower the engine speed, the tighter the throttle, resulting in greater energy loss. Therefore, the Valvetronic engine can save fuel consumption by subtracting the throttle, especially at low speed. In a traditional engine, the air in the intake pipe passes through the throttle and then the intake valve at the top of the cylinder 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.

Valvetronic engine, as the name implies, Valve means valve tronic, which means electronic control. After canceling the throttle, the engine directly controls the intake air volume by electronically controlling the opening depth of the intake valve. The overall mechanism is actually quite complicated and professional to explain. Generally speaking, the signal when the traditional engine steps on the throttle is to control the throttle of the intake pipe through mechanical transmission. When the Valvetronic engine steps on the gas pedal, the signal is transmitted to the stepping motor at the top of the engine intake and exhaust valves by electronic means. 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, the shallower the intake valve is opened, and the deeper the throttle is stepped, the deeper the intake valve is opened. Valvetronic engine eliminates the throttle valve and directly controls the intake valve to electronically adjust the intake air. In addition to saving fuel, this design also has an important advantage, that is, the reaction time of the throttle is accelerated. In traditional engines, the throttle is controlled by the throttle. When you step on the accelerator, the throttle will open, and air will not enter the cylinder in large quantities until it flows into the intake branch pipe. Valvetronic engine directly controls the opening depth of the intake valve by stepping on the accelerator, and a large amount of air immediately enters the cylinder.

The opening depth of the intake valve of Valvetronic engine is as shallow as 0.25mm and as low as 9.7mm times 38.8 times. The reaction time from the shallowest to the deepest is only 0.3 seconds. BMW's Valvetronic engine is made in a brand-new engine factory in Britain. The whole Valvetronic system is a pre-assembled module, which can be directly installed on the engine cylinder head. BMW claims that the efficiency of engines using Valvetronic technology is 14% higher than that of traditional engines, but this is not entirely due to Valvetronic technology. According to BMW, 7% of it comes from Valvetronic technology, 3% from reducing friction loss and 4% from 6-speed automatic transmission. However, because Valvetronic engine is equipped with many intake valve control mechanisms, there are many mechanical contacts and frictions, and the efficiency and smoothness of the engine are not good when it exceeds 6000 rpm.

Valvetronic engine uses a combination of software and hardware to replace the throttle structure of transmission. Valvetronic means that electronic control replaces the traditional mechanical control valve mechanism.

Valvetronic modifies the timing and lift of the intake valve. Valvetronic system has the same camshaft as the traditional engine, as well as eccentric shaft, roller and ejector pin, which are driven by stepping motor. By receiving the signal from the throttle position, the stepping motor changes the offset of the eccentric cam and indirectly changes the actuation of the intake valve through some mechanical transmission.

Comparison between Traditional Valve Mechanism and Valvetronic Mechanism The fuel injection system determines the amount of fuel required for engine combustion by monitoring the air flow through the circulating throttle, that is, the greater the throttle opening, the more air will flow into the combustion chamber. At a lighter throttle, the throttle is even close to closing. When the piston is still running, some air enters the intake manifold. At this time, there is some vacuum, suction and pump resistance in the intake manifold between the combustion chamber and the throttle valve, which wastes energy. Engineers call this phenomenon? Pump loss? (Pumpingloss), when idling, the throttle is only partially opened, so the energy loss is more.

By improving the spiral gear of the motor to change the rotation of the eccentric shaft, the intermediate rocker arm is driven to move with the traditional camshaft, and then the pressure is transmitted to the rocker arm before the valve is depressed.

Valvetronic can minimize the loss of the pump by reducing the valve lift and the amount of air entering the combustion chamber.

Compared with the traditional biconvex engine, Valvetronic uses extra eccentric shaft, stepping motor and some intermediate rocker arms to control the opening or closing of the valve. If the rocker arm is pressed deeper, the intake valve will have a higher lift, and Valvetronic has a way to control the valve lift freely. Long intake means large valve lift, and short intake means small valve lift.

Advantages:

When the cooling water of Valvetronic engine flows through the cylinder head, the temperature can be reduced by about 60%.

The size of the pump is only half of the original size, reducing the power loss by about 60%.

The oil in the power direction is heated rapidly, which reduces the power use of the hydraulic pump.

Install the water pump and power pump on the same shaft, and install a heat exchanger between cooling and engine oil to reduce the temperature by 30%.

Million car purchase subsidy