Is the engine 8 valves necessarily worse than the 16 valves?

Three-cylinder 12-valve means that the engine has 2 intake valves and 2 exhaust valves per cylinder, the four-cylinder 16-valve engine has 2 intake and exhaust valves per cylinder, and the four-cylinder 8-valve has 1 intake and exhaust valve per cylinder. More valves are just the improvement of the car gas supply system, see the car exhaust emissions dripping, indicating that the car emissions are very good, look at the fuel consumption to see the actual fuel consumption of the vehicle before leaving the factory on the body pasted with the actual fuel consumption logo, this value is the car in the theoretical state of 100 kilometers of fuel consumption, the lower the value of the car more fuel-efficient, if you do not look at the car model and manufacturer to the Internet to check the bottom. This value is convincing (this value is high, it is pale to say anything), look at the engine power to see the compression ratio, the higher this value, the stronger the power of the car!

Fuel saving is not to see how many valves, the valves are only able to meet the intake and exhaust conditions of the car at high speed, there are 5 valves in a single cylinder, 3 intake valves and 2 exhaust valves, this has nothing to do with fuel saving, a few years ago there was a lubricating oil advertisement that the lubricating oil drove 500 kilometers without gasoline, and there are experiments as proof, at that time fooled people who do not understand, you have to ask the sales staff to indicate the actual fuel consumption of the car, how much fuel is consumed by the car for 100 kilometers, see if the fuel is economical to see its fuel injection system, The fuel injection system is now all EFI, but the EFI has good and bad, it is divided into continuous injection and sequential injection, the best is sequential injection, it belongs to intermittent injection, which cylinder is ignited and which cylinder it sprays, which cylinder can be used to achieve starting thickening, warm-up thickening, accelerated thickening, full-load thickening, deceleration and thinning, forced oil cut-off, automatic idle control and other functions, which are directly related to fuel consumption.

Secondly, the secondary air injection combustion technology and the exhaust gas reprocessing technology generated after the combustion of the mixture gas are related to fuel consumption, and the car has an OS sensor and a three-way catalyst, which reduces the harmful gases such as CO, NOx, and CH in the exhaust gas into CO2, N2, and H2O (water) harmless gases.

Personally, I think the above is too absolute! More valves do not necessarily mean that the power is stronger! Performance is good.

Imagine: for example, 16 valves, doing so many valves is nothing more than to promote more air intake, good combustion, strong power, and better emission effect, but the fuel consumption and mechanical wear are very large, and the failure rate is high; Speaking of 8 valves, if I want to increase the power, I can change the turbocharging, increase the valve diameter, and increase the fuel supply, which is better than the 16 valves! And the 8-valve mechanical wear is smaller, the failure rate is small, and it is more traditional.

The engine with more valves needs technical support, and the engine made by the technology is poor! On the whole, each has its own advantages and disadvantages, depending on how to say it.

Of course, the more valves, the more power, the better the performance, but the more oil is used.

Eight-valve: the design structure is relatively simple, the cost is low, the maintenance is convenient, the low-speed performance is good, and it is suitable for urban areas.

Sixteen-valve: The advantages can be fully reflected at high speeds, so that gasoline combustion is more sufficient, fuel consumption is reduced, and power is increased.

The average car has 4 cylinders, each cylinder has two valves, one intake valve and one exhaust valve, which is 8 valves, which is the so-called 8V, which is a traditional engine. The same is true for 16 valves, which refers to 4 valves per cylinder, 2 into 2 rows or 3 into 1 row (generally 2 into 2 rows), and 16 valves for four cylinders, which is the so-called 16V, which is a multi-valve engine, and many more.

In fact, 8V and 16V have their own advantages, 8V design structure is relatively simple, low cost, easy maintenance, good low-speed performance, suitable for urban areas (because the efficiency advantage of 16V at low speed can not be reflected, even not as good as 8V), the disadvantage is that the power is difficult to improve, especially at high speed when the inflation efficiency is low and the performance is weak. The advantages of 16V can be fully reflected at high speeds, so that gasoline combustion is more sufficient, fuel consumption is reduced, and power is increased.

A cylinder has only two valves: one each for the intake and exhaust valves. Four cylinders, that is, eight valves, one cylinder, 2 intake valves, 2 exhaust valves, a total of 4 valves, four cylinders are 16 valves, 16 valves are better than 8 valves, that is, the intake and exhaust ports are larger, and the intake and exhaust are naturally smoother.

You can also see it by drawing a big circle on the paper, first draw a big circle to represent the cylinder, then draw 2 small circles in it to represent the valve, and another is to draw 4 small circles in it to represent the valve, and the small circle is drawn as large as possible.

Generally speaking, with the same displacement, the more valves, the better the intake and exhaust efficiency.

There are more valves, so the mixture of air and gasoline at the same pressure atomizes better and more fully, and the engine technology is advanced or not, there are many measurement indicators, among them, the number of cylinders and valves is indeed one of them.

Generally speaking, under the same bore, the more cylinders, the larger the displacement, and the higher the power; Under the same displacement, the more cylinders, the smaller the bore, and the speed can be increased, so as to obtain greater lifting power. With the same displacement, the more valves, the better the intake and exhaust efficiency.

The two-valve engine per cylinder is biased towards low-speed torque, like the Volkswagen's 2000 rpm can output the maximum torque, 95%, and the maximum torque appears at 3500 rpm, which means that the power will decay after this speed, so the two-valve engine is more suitable for urban driving. But now many four-valve engines per cylinder have a variety of variable valve timing technology and even supercharging technology, such as Ruiyi's engine can output 9 percent torque at 1600 rpm, and it lasts until the maximum torque output speed of 4000 rpm, like the current engine with variable valve four-valve engine in general, 2000 rpm can output 85%-90% of the torque, and the four-valve engine is higher than the two-valve in terms of maximum power and maximum torque, so in general, The advantages of the 4-valve engine per cylinder are still relatively large, and the 2-valve engine mainly has fewer components, which is not easy to break, and the maintenance is relatively cheaper, but under the technology of variable valves, it is indeed outdated.

The 2nd floor is good, and the 4-valve is the development trend.

The intake valve is larger than the exhaust valve based on the amount of inflation and exhaust.

1. Theoretically speaking, the inflation volume and the exhaust volume are equal, and the opening and closing time of the exhaust valve and the opening and closing time of the intake valve are also equal. But in reality, this is not the case, because the throttle valve directs the rotational speed, the valve opens and closes large or small, and the cylinder should be filled with a mixture equal to the atmospheric pressure (about 1 kilogram square centimeter) when the suction is finished.

2. However, when the gas flows through the inlet pipe and the inlet valve, it must be subjected to resistance, in order to overcome these resistances and make the mixture flow at a certain speed, a part of the pressure must be consumed, so the air pressure in the cylinder is always lower than the atmospheric pressure. The density of the gas varies with the pressure, and the density decreases at low pressure, and the weight of the actual inhaled mixture decreases.

3. In order to solve and reduce the influence of airflow resistance, it is necessary to increase the cross-sectional area of the airflow path at the inlet valve, that is, to increase the area of the air valve. In the case of thin air in plateau areas, the area of the air intake channel should be increased, otherwise the engine will not reach its rated power in these areas.

This is designed to increase the engine performance of the car.

The valves are pressed open by the cam and the valve springs are closed. The intake valve opens when the suction mixture needs to be fed into the cylinder, and the exhaust valve opens when the combustion exhaust gases need to be discharged.

Since the intake is "sucked" in, while the exhaust is "pushed.""out, so it is more difficult to intake than to exhaust, and the more air intake, the better it burns and the engine performs better. The intake air is sucked by vacuum, and the exhaust gas is pushed out by extrusion. Therefore, it is easier to exhaust than to intake.

With higher and higher requirements for engine performance and increasingly stringent exhaust emission regulations, the structure of 2 valves per cylinder (i.e. 1 intake valve, 1 exhaust valve) has become somewhat outdated, and now more and more engines are using a 3-valve structure per cylinder (2 intake valves, 1 exhaust valve) or a 4-valve structure per cylinder (i.e. 2 intake valves, 2 exhaust valves).

Generally speaking, in the case of the same displacement, the more valves, the better the intake and exhaust efficiency, just like a person who needs to open his mouth to breathe when he is tired and out of breath. Traditional engines mostly have one intake valve and one exhaust valve per cylinder, and this two-valve valve mechanism is relatively simple, with low manufacturing cost and relatively easy maintenance. For ordinary engines with low output power requirements, two valves can obtain more satisfactory engine output and torque performance.

There are pros and cons, but in general it is still an advanced point of 16 valves! Because the timing of the 8-valve valve remains unchanged, the intake and outlet are staggered, which has a certain fuel economy! However, at high speeds, the power is insufficient due to insufficient air intake!

The high-speed power of the 16-valve is sufficient, but the structure is complex and the maintenance cost is high!

You can add to learn the parameters of the car together.

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