Some 92 cars add 95, which is really quiet to drive, but not all 92 cars add 95, which will make the sound smaller and sometimes backfire.

For example, some people have acne on their faces. After using acne products, their faces became smoother and more beautiful. However, some people are allergic to ointment, and instead of getting better, they are more likely to rot.

Knock is reduced, and noise is indeed reduced.

92 cars plus 95 make it quieter to drive. The main reason is that the knock noise becomes smaller.

There is a paper in the magazine Internal Combustion Engine and Accessories. Discussion on noise pollution of automobile engine and its control It is said that when there is surface ignition or knocking inside the cylinder block, knocking noise will be generated.

After adding 95 # gasoline to 92 cars, the octane number of gasoline becomes higher and the antiknock performance becomes better, which can reduce or inhibit knocking, thus reducing noise.

"Anti-explosion" is simply: the capacity is not easy to ignite.

No.95 gasoline is like ordinary firecrackers, which should be lit with a lighter; 92 is like a cannon. When you throw it directly on the ground, it will explode with a bang.

There is no need to add 95 to reduce the noise.

If the knock is serious, the situation will be different, but the impact is not great.

Although adding 95 to 92 cars can reduce noise, it makes little difference for cars with good car condition and less serious knock.

Zhejiang University has a paper "Research on the calibration system of electronically controlled gasoline engine and multi-objective optimization method of ignition advance angle".

The ignition matching standard of the engine is to avoid knocking, which is embodied in: strong knocking does not occur at medium and low loads, and knocking cannot occur at high loads.

To put it bluntly, the 92 car itself is an ignition system set according to the 92 gasoline engine oil, and knocking is an effective suppression state.

Add 92 or 95, it's not too much, and the difference is not as big as we thought.

However, for example, if the working condition of the engine is not very good, such as the engine knocking due to carbon deposition, adding 95 can improve the knocking noise. This is one of the reasons why those old cars become quieter after adding 95.

In addition, the quietness of the car is mainly reflected in low-speed working conditions.

There is a paper in the magazine of Equipment Manufacturing Technology. The noise analysis and noise reduction measures of automobile engines say that the noise emitted by engines mainly includes combustion noise, mechanical noise and aerodynamic noise.

When the engine is running at low speed, combustion noise is the main noise source. At high speed, mechanical noise and aerodynamic noise are the main noise sources.

To put it simply: detonation "boom" is combustion noise, and it is the main noise source only at low speed. That is: obviously, I can hear it. If it is idling, the difference may be obvious.

When the speed is relatively high, the sound generated by the movement of internal parts of the engine is the main one.

It's like: you ride a motorcycle very fast, the wind is strong in your ear, the engine can't hear you, and the sound of the engine "ah, ah, ah" is not very audible.

"Bang, bang, bang, bang, bang, bang, bang, bang, bang, bang, bang, bang, bang." The original sound of burning, right?

Adding 95 # gasoline to improve engine noise is more suitable for old cars with serious knock problems and more carbon deposits, especially at low speeds.

Theoretically, the new car will be louder.

But for a new car with almost no knock, adding 95 # gasoline may make the sound louder.

First of all, the engine will ignite the mixture before the power stroke, and it will ignite in advance.

Combustion has a combustion propagation speed, and it takes time from the spark source to the combustion of all mixtures.

It's like: when you order a piece of paper, it must burn from one end to the other, not a little, and the whole paper is burned, right?

Therefore, early ignition is beneficial to the explosion of more energy during the power stroke.

When you ran 100m, you ran before the starting line. You must have been faster than others at first, and went out with a bang.

After adding 95 # gasoline, the antiknock performance is better, the ignition advance angle can be earlier than that when adding 92 # gasoline, and the pressure generated during power stroke combustion is greater.

It's like: the person in front runs to 1m, the other person sprints to the starting line at full speed, and then "wow" goes on and on, and the result is generally better than the previous one.

Anyway, we have talked a lot before, so don't worry too much, that is, the greater the combustion pressure, the greater the vibration and the louder the sound.

As I said before: 92 cars plus 95, the power is stronger, almost. Stronger, louder.

I feel that there is a big gap, which is basically a psychological effect.

What I just said is all theoretical, but the gap is actually quite small. If you add 95 and feel that the car is silent, then nine times out of ten it is really a psychological effect.

In behavioral economics, there is a theory called "veblen effect", that is, the higher the price of a commodity, the more consumers are willing to buy it, and the better the effect of the commodity will be.

For example, researchers at the University of Cincinnati in the United States injected 12 Parkinson's patients with "drugs" twice and told them that "one time was worth 1000 dollars, and the other time was worth 65 dollars."

Both "drugs" have achieved the curative effect, and the more expensive "drug" has the higher curative effect. But in fact, the ingredients of these two "drugs" are exactly the same.

To tell the truth: 95 # gasoline is more expensive, and it feels better than 92 # gasoline, but it is quieter; Actually, when I drive, I really feel quiet.

Cars with knock problems are quieter by adding 95.

Generally speaking, 92 plus 95 is quieter for cars with knock problems.

But for cars in good condition, the difference between adding 92 and 95 is really small. In addition to paper money, sometimes adding 95 will make more noise.

92 cars and 95 cars are more comfortable to drive. What happened?

So I don't think it's cost-effective to add 95 simply for noise reduction.

But I heard someone say, "A car with a price of 92 plus 95 can save fuel and improve power." Is it true?/You don't say. If it is true, how much money can it save? How much can it be improved?

The same tank of oil, someone added 95, even 50km more than adding 92. Is this illusion and psychology? Or does it really exist objectively?