The hottest multi valve engine technology

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Multi valve engine technology

multi valve technology had appeared as early as 1912. The first multi valve engine was Peugeot GP racing engine at that time. Later, this engine was also used in Bentley and Bugatti concept cars, but these models are not mass-produced cars. In the next 50 years, ordinary civilian cars still use the traditional 2-valve design. This situation lasted until the 1960s. Honda adopted the engine with multi valve technology on its 600 model, which was the first ordinary civil vehicle to adopt the multi valve technology taking the sensor of S-type experimental machine as an example. In the 1970s, more cars began to adopt the 4-Valve technology, such as lotus in 1976, Chevrolet Cosworth Vega in 1975, BMW M1 in 1979, etc. At this time, the 4-Valve engine still uses a single camshaft to drive the valve through the rocker arm

BMW M5 V10 engine

in the early 1980s, Honda adopted a 3-valve engine design and matched it to its mainstream models. By the mid-1980s, Toyota and Honda began to generally adopt the 4-Valve engine, becoming the leader in this technical field. Its mainstream models all adopted this engine technology. European automakers are nearly 10 years behind Toyota and Honda in this field

multi valve technology can increase the output power of the engine by improving the intake air. Due to the limited intake cross-sectional area of the 2-valve engine, it is easy to cause its intake to be blocked at high speed. This situation can be effectively changed by using multiple valve technologies

the following describes the classification of various multi valve engines

3 valve engines

in the early days of multi valve engines, 3 valve was widely used because of its simple technical structure - the three valves can be arranged in a straight line, so only one camshaft is required to drive the inlet and exhaust valves of a row of cylinders at the same time. Until now, a small number of multi valve engines have adopted this low-cost design, such as the V6 and V8 engines of the old Mercedes Benz, the 1.3-liter Qianlima engine of Dongfeng Yueda Kia, and so on. Of course, this low-cost design is very limited to improve the working efficiency of the engine

4-valve engine

the traditional 2-valve engine can only occupy 1/3 of the top area of the combustion chamber as the air inlet area, and the air inlet efficiency is limited. Compared with the current 2-valve engine, the focus in China is on the vamou core attack engine. The intake cross-section can be increased by more than 50%, which is more suitable for smooth operation at high speed. At the same time, because the 4-Valve design can place the spark plug in the center of the combustion chamber, the flame of the spark plug can be more evenly distributed to all corners of the combustion chamber, and the mixture can be burned more fully with less heat loss. Therefore, the 4-Valve engine is also more conducive to improving combustion efficiency and reducing emissions

4 valve engine can design two camshafts to drive the valves, one to drive the inlet valve and the other to drive the exhaust valve. The control can be more accurate and more new technologies can be adopted. Nowadays, most mainstream 4-Valve engines adopt the design of double overhead camshaft. Honda and Mitsubishi still like to use single overhead camshaft in their ordinary civilian cars for the purpose of reducing costs. It needs to arrange rocker arms on the camshaft, and finally drive the air valve through the rocker arms. Although this design can reduce the cost, it increases more friction resistance and motion inertia, which affects the power output of the engine at high speed. Therefore, Honda and Mitsubishi sports vehicles are equipped with engines with double overhead camshaft design for the purpose of improving performance

5 valve engine

this is a controversial multi valve engine technology. The biggest controversy is whether the design of five air valves per cylinder can really effectively increase the working efficiency of the engine. At present, Volkswagen and Audi have adopted this technology on the engines of many models, but it has not significantly improved the power output of the engine. Many 5-Valve engines with the same displacement and technology have no obvious advantages in power and torque compared with the mainstream 4-Valve engines. In fact, Volkswagen itself is gradually replacing the previous 5-Valve engine with the traditional 4-Valve engine

compared with the 4-Valve, the early 5-Valve can not provide higher intake efficiency. However, if the combustion chamber can be designed into a plum blossom shape as shown in the figure, the valve may cover a larger area. The F355 of Fraser adopts this design to improve the respiratory efficiency at high speed. However, its disadvantages are also obvious. If there is no size limit, the faster intake will damage the torque output at low speed. Therefore, this design is not suitable for ordinary civilian vehicles, but more suitable for sports vehicles

in the current 5-Valve engine, each cylinder has 3 inlet valves and 2 exhaust valves, which are distributed in a plum blossom shape. Although the exhaust valve is relatively large in a single view, the total area of the intake valve is larger. On F355, the inlet valve on the outside is opened 10 degrees ahead of the inlet valve on the inside, which makes it easier to form vortices and fully mix air and gasoline, so it has higher combustion efficiency and better emissions

in general, the advantage of 5-Valve is not obvious. Only a few automobile manufacturers adopt this technology (Volkswagen, Ferrari and early Bugatti). However, due to its advantages in the high speed range, there are still a few manufacturers who have been keen on the 5-Valve technology, even including the F1 car of Ferrari. However, this technology has not been used for a long time. Within a few years, the F1 engine of Ferrari changed back to the 4-Valve design

disadvantages and Solutions - variable valve technology

the early 4-Valve engine also has disadvantages compared with the 2-valve engine - there is no good torque output at low speed. The reason is very simple - a large intake cross-sectional area will slow down the air flow, which is very detrimental to the low speed operation of the engine. When low flow rate air flows into the intake manifold, the air and fuel will not be fully mixed, which is easy to produce knock, and the torque output will also be reduced. Therefore, the traditional 4-Valve engine can only effectively improve the engine performance at high speed. With the popularity of variable valve technology in more and more vehicles, this situation has changed. The following is an example of variable valve technology: Toyota t-vis engine low engine speed high engine speed Toyota put forward the concept of t-vis (Toyota Variable Intake System) in the mid-1980s. T-vis improves fuel mixing efficiency at low rpm. The principle is very simple. A throttle valve is installed in one of the intake manifolds. When the speed is below 4650rpm, the throttle valve is closed, which is equivalent to a 2-valve engine. When the speed exceeds 4650rpm, the throttle valve is opened, which is equivalent to a 4-Valve engine. 5. Why do we need to lay out a batch of cutting-edge new materials

since this technology effectively improves the combustion efficiency and torque output of 4-Valve engine at low speed, many manufacturers have adopted this technology after Toyota. (end)

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