Why do modern cars have less engine braking?
Content
This is a comment we often hear from older people that the more work goes on, the more modern engines lose engine braking ...
And if for most drivers this is not very important, then it is completely different for drivers living on steep slopes or on steep slopes. In fact, anyone who has ever been to the mountains knows that when descending the pass in one pass, it is difficult to cope with the brakes. At the bottom, we generally have more teeth, and since we are often loaded in this context (vacation), this phenomenon is all the more important.
To overcome this, we can use the engine brake, and we even have to! The signs sometimes remind you of this because it can be very dangerous to go without it.
Read also: engine brake operation
Causes of loss of engine braking
Come on, let's lengthen the wait because the response is going to be pretty quick and harsh, so why is engine braking less powerful on recent cars?
In fact, this is due to the evolution of engines, namely, with the fact that almost all modern engines are equipped with a supercharger, namely a turbocharger in the overwhelming majority of cases.
You are going to tell me that you do not see the report, and I am ready to admit it, but I want to omit that the presence of this organ causes a profound change in the characteristics of the combustion chambers ...
Indeed, as the name suggests, a turbocharger compresses ... It compresses air in order to transfer it to the combustion chambers (in fact, its role is not to compress air, but to supply it to the engine and fill the engine with air. must be compressed, otherwise it will not pass! Note that for optimization it is cooled by an intercooler to reduce the intake air volume a little more).
The conclusion is that the presence of turbocharging inevitably leads to a decrease in the compression ratio of the engine, because otherwise the request for the turbocharger would cause too much stress in the cylinders (too much compression with spontaneous ignition / detonation of the key). ... Therefore, manufacturers reduced the compression ratio of the engines, while the turbines ran harder and harder.
And I suggest you review how the engine brake works to understand better.
Another reason for the loss of engine braking?
To all this is added one more reason, even two ...
First of all, let's not forget that the inertia of modern cars is more difficult to overcome due to the increase in the weight of cars over time, and therefore engine braking is felt less and less ...
Added to this is the emergence of three-cylinder engines, which thus further reduce this phenomenon (the fewer cylinders I have, the less benefit I get from pumping and compression).
All comments and reactions
Dernier comment posted:
beans (Date: 2021, 04:13:09)
On car crates, you can also mention swimming strategies in which Neutre can lift its foot on the motorway with a dedicated pump to reduce consumption.
Il I. 2 reaction (s) to this comment:
- Administrator SITE ADMINISTRATOR (2021-04-13 14:47:37): The famous freewheel mode, I did not dare to talk about it and confess everything to you.
Therefore, this means that it is first and foremost important to maintain as much kinetic energy as possible in order to save fuel. The engine brake stops injection but wastes this precious kinetic energy ... - LOBINS (2021-08-26 18:58:10): I have more engine braking on the 308hp 1.2 130L puretech than the 206 HDi 1.4L, but 3-cylinder and more weight ...
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Extension 2 Comments :
| Nico BEST PARTICIPANT (Date: 2021, 04:12:19) |
Very good question, dear Admin! I saw this, like many, but never looked too much, and indeed, I took two acquaintances to see: My Laguna 3 2.0 dci 130, compression ratio 16: 1 Old Passat 1.9 Tdi 130, compression ratio 19: 1 We can say that with the equivalent power, 10 Nm more and 0.1 liters more on the Dci, that would be great than the nà © ni! Il I. 4 reaction (s) to this comment: (Your post will be visible under the comment) |
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