Which one is more powerful than manual transmission or automatic transmission?

Which one has a stronger start than a manual or automatic transmission? When asked this question, most people’s first reaction is: Of course, manual transmission is more powerful. The reason is: racers all use manual gears, and their 100km/h acceleration time is shorter than that of automatic gears; otherwise, racers don’t need manual gears!

This reason suddenly sounds plausible, but the answer will surprise you. Let’s find out together.

First, try to find two such cars, the engine displacement is the same at 1.8T, the idle speed is 800r/min, the tires and the body are the same, one is automatic, and the other is manual. The manual gear is in 1st gear, the automatic gear is set to D gear, and the brake pedal is released simultaneously; which vehicle starts more powerfully?

Assume that the torque output by the engine at 800r/min idle speed is 20N.m (just an assumption, although it is unreasonable), assuming that the transmission ratio of the first gear of the automatic transmission and the manual transmission is both 3:1. The manual transmission is equipped with a manual transmission. The driving torque of the vehicle in gear will be less than 60N.m (for the convenience of comparison, please ignore the existence of the main reducer first, and assume that the differential is the same) because the clutch cannot be released at once we first assume that it is 60N.m, and the automatic What is the driving torque of the car?

There is a torque converter in the middle of an automatic transmission car (CVT and DSG can be without, except); the torque converter converts torque, as the name implies. Yes, this kind of torque is to be increased. The ratio of output torque to input torque is called the conversion coefficient. When the output speed is zero, the zero-speed torque conversion coefficient is usually about 2 to 6—assuming that the torque conversion coefficient of the car is four and the intermediate value is taken. When the engine idle speed is 800r/min, the vehicle’s driving force is 60X4=240N.m, but since the automatic transmission is a wet clutch, the D1 gear is related to the clutch, and the brake can’t transmit 100% of the power. Assuming that it is transmitted according to 80%, its torque also reaches 192N.m, so the moment of starting is equivalent to 3.2 times the torque of the manual gear!

The answer is obvious: the starting moment is more powerful when the automatic block starts! However, when the ECU controls the number of revolutions increases, the automatic transmission shifts up the gearbox, but the torque will become smaller. According to the power = torque X speed formula, it is not as good as the manual transmission to force the gear to pull the speed. That’s why starting a manual transmission is faster!

Then why do cars use manual transmissions instead of automatic transmissions?

A netizen replied: The automatic transmission is stronger than the manual transmission at the beginning, but as the output speed of the automatic transmission increases, its transmission torque will decrease, and finally, the lock-up clutch is engaged. (Hydraulic torque converter transmits torque at 1:1), plus, the planetary gear mechanism relies entirely on wet friction plates and clutch plates for transmission, and the torque is lower than that of the manual transmission in the same gear and speed ratio.

In addition, the manual transmission is more flexible than the automatic transmission. For beginners, using manual gear is slower than using automatic gear; for intermediate hands, using manual gear is only a little slower than using automatic gear. After long-term practice, the results of the two will gradually become closer; For the masters, it is slightly faster to use a manual transmission than an automatic one. With the improvement of proficiency, it will gradually reach the conditioned reflex state. Try not to squint at the tachometer when shifting gears, and experts use your ears to shift gears. The advantage of a manual transmission is that you can forcefully step down from 1st gear and go through the corner quickly. At this time, the accelerator is not released, the brake is not pressed, and the car will have a higher and faster speed when cornering.

B netizen asked: Don’t you know that the automatic transmission has a “kick-down” function when you are in a hurry to refuel?

C netizen replied: The automatic transmission has two disadvantages, so it is not suitable for racing cars: 1. The shifting efficiency is low, and the power loss is significant; 2. It cannot withstand a lot of torque (racing cars). But they are all high-horsepower engines). Currently, popular dual-clutch transmissions in civilian vehicles, including DSG, SST, etc., have fast-shifting speeds and high efficiency, but they cannot withstand excessive torque. The Chinese-standard GTR R35 was told to only use LC four times (Ejection starts) because the gearbox cannot withstand enough. However, manual gears are not ordinary in many racing competitions, such as WRC and FIA GT. They all have electronic clutch control. Except for starting, they only step on the clutch at particular times (for example, the WRC is in Scandinavia). Action to maintain high revs). So many times, you can control your vehicle better with a manual transmission than with an automatic transmission.

To summarize, the Toyota 86/BRZ circulating on the Internet “cut 2nd gear, 7300 dry the whole city”. However, it is a joke; it can also be seen how important control is in the so-called automatic transmission cars ECO and SPORT. The mode (shift logic written by the program) is only suitable for economic and civil use, not for highly challenging competitions! For engines of the same displacement, the acceleration time of 100km/h is shorter for many manual gears than for automatic gears. In addition, the manual gears of racing cars are mostly manual sequential transmissions, which are convenient to shift.