Analysis of excellent disadvantages of various types of automatic transmission


The automatic gearbox has five categories:

1.AT 2.AM T3.DCT 4.CVT 5.ECV

This five types of transmission theories have their own advantages and disadvantages, but there is a "CVT · Stepless Speaker" that has been used completely without the advantage; then the "CVT · Stepless Speakers" use the conical wheel and steel belt, in addition to the rest Four kinds of gear group shift. With different gear meshing shifts, there is no need to worry about wear, but the cone steel strip with rolling friction is a wave steel strip that cannot be avoided, and there is a short life of wear.

Key: CVT's cone steel strip has wear problems, in order to reduce wear, there is a high demand for the gap oil; but the transmission performance of the transmission oil in the cold start in the low temperature environment is very poor, so it is started. After a few minutes or even ten minutes, it can then speed up the speed.

The original geothermal train will greatly enhance the fuel consumption of the vehicle, because there is a large thermal loss during the temperature of the water temperature, and the ECU has to increase the speed and the amount of injection to pull the power to stabilize the speed. Therefore, the continuously variable transmission is really very poor. Once you can use low-class pull-free automobiles; however, as the manufacturing cost is the same as the popularity of AMT and DCT, CVT already has the necessity of "retreat". .

Automatic transmission with clutch

The evaluation of the AMT · Electronic Control Machinery automatic transmission is different. It is considered that it is poor because of the severe-changing block of AMT, which is to accept two major advantages of such a transmission.

long lasting

Low maintenance cost

The essence of AMT is the MT manual transmission, and the components such as electronically controlled, solenoid valves, clutch control motors are upgraded to automatic gear; the mode of shift is RNDM, which does not have any difference from the standard automatic block, so this model Not the so-called "semi-automatic". Then, the service life of the clutch and gear sets will naturally be more ideal, especially which is a feature that is a highly enthusiasm, which can protect the clutch.

The DCT · Double-clutch alternator is an upgrade of AMT, and AMT has only one set of clutches and power input shafts. The shift principle and process are the same as the manual gear, so there will be obvious tempering effects; but the double clutch is from two groups The clutch separately controls two power input shafts, synchronized halflocks during shifting, that is, the half-linking operation as a binding gear when it is about to separate a forward gear, and the separation instant can be combined to effectively shorten the shift time. .

The shorter the transmission time, the more flat, so actually DCT is more ideal than AT in the smooth road; however, the dry double clutch in the congestion road will be very bad, because of the MT / AMT The same dry friction clutch will reduce the friction of the clutch, resulting in the abnormality of the clutch separation combination.

Therefore, the stability of dry double clutch is relatively poor, but the wet dual clutch is generally good; because the clutch is lubricated and dissipated by transmission oil, even if the high frequency half-link does not have to worry about wear High temperature problems, to this wet double compound is combined with a fuel vehicle transmission capable of side by side.

Advantages of the AT gearbox

AT is generally considered "the most smooth", in fact, only a dry-style double clutch for early problems, there is such a wrong conclusion! Many well-known brands of AT transmission have problems with refreshing, such as Aixin, Dai Moz, Jette, Xifu, Shengrui and Dongan. The reason is mainly the impact of the shift logic and shifting speed, so only the technical level of the dual clutch is further improved, and AT will be rejected.

But is AT whether there is an advantage in terms of service life?

"Hydraulic torque converter" is why AT is relatively high, and most car enthusiasts believe that this torqueizer does not have wear problems, and the drive is the pump wheel agitating the transmission oil flow, and the turbine is pushed as the drive oil. However, in fact, as long as the speed is slightly higher or raised to 2 gear, the one-way clutch in the torque converter also pushes the turbulence rigid binding drive, and the wear is also present.

However, the liquid torque converter is still durable than the wet double clutch, so the off-road vehicles and pickups at this stage also choose AT; but after mixing technology has gradually become mainstream, the AT / DCT / CVT will inevitably be eliminated. Only AMT may continue to serve in the commercial model, because the manufacturing cost is low and the low speed motor needs to be shifted.

ECVT and reducer

ECVT is completely different from CVT, and the original meaning of Continuously Variable Transmission is not "unpolated speed", and translation into a transmission that can continuously transmit power is well understood. As long as the engine's power input is not cut in the process of change the transmission ratio, this is an unpolated speed.

The ECVT actually does not have the concept of the forward gear, because its structure has only two motors and two gear sets; the internal combustion engine is connected in series power generator to control a forward gear, the drive motor controls the other forward block (reducer). The engine and ECVT are only combined and separated, the transmission ratio is fixed, and the speed is completely relying entirely on the internal combustion engine and the motor speed (power horsepower); this concept is equal to the direct drive, and the speed relies on the engine will of course very linear, and don't worry Wear problem.

Then there is no competitiveness that is not competitive without worrying about wear and very smooth, AT is not competitive; as long as ECVT-based plugging hybrid cars gradually enriches the model, the era of fuel cars is basically over.

It will eventually be used as the only option in the reducer, that is, the gear structure used by the ECVT drive motor; the speed can still rely on the motor itself, so it will still be very linear and do not worry about wear problems. This is the characteristics of various types of transmission. At this stage, there is also a space for debate. It is also a topic of the past.