It is recommended that you go to "First Line Marriage" to find a partner. Several single buddies in our unit are looking for partners there. It is free to register, read letters, open and view contacts for free. method etc. I think it's pretty good and the success rate is relatively high.
.
An automatic transmission car refers to a car that uses an automatic transmission (automatic transmission). It can automatically change speed and torque according to road conditions, and the driver can concentrate on the road traffic. Rather than being confused by shifting gears. There are three common types of automotive automatic transmissions, namely hydraulic automatic transmission (AT for short), mechanical stepless automatic transmission (CVT for short), and electronically controlled mechanical automatic transmission (AMT for short). At present, AT is commonly used in cars, and AT has almost become synonymous with automatic transmission. Therefore, it is extremely necessary to focus on AT.
1. Hydraulic automatic wave (AT for short)
Structure Compared with manual wave, hydraulic automatic wave (AT) is very different in structure and use. The manual wave is mainly composed of gears and shafts, and variable speed and torque are generated through different gear combinations; while AT is composed of a hydraulic torque converter, planetary gears and hydraulic control systems, and achieves variable speed and torque through hydraulic transmission and gear combination. moment. Among them, the torque converter is the most characteristic component of AT. It is composed of components such as a pump impeller, a turbine, and a guide wheel. It directly inputs engine power to transmit torque and clutch action.
The pump impeller and the turbine are a pair of working combinations. They are like two fans placed opposite each other. The wind blown by one fan will drive the blades of the other fan to rotate, and the wind becomes the medium for transmitting kinetic energy. , if liquid is used instead of air as the medium to transmit kinetic energy, the pump wheel will drive the turbine to rotate through the liquid, and then a guide wheel is added between the pump wheel and the turbine, and the reaction force can achieve a speed difference between the pump wheel and the turbine. Achieved variable speed and torque. Since the automatic speed and torque range of the hydraulic torque converter is not large enough, several rows of planetary gears are connected in series behind the turbine to improve efficiency. The hydraulic control system will automatically control the planetary gears as the engine operation changes, thereby achieving automatic speed and torque changes.
The automatic gear shifting of the auxiliary mechanism cannot meet the various needs of driving, such as parking, reversing, etc., so there is also an intervention device, that is, a manual lever with signs P (parking), R (reverse), N (neutral), D (forward), and the forward gear also has additional gears "2" and "1" for starting and going up slopes. Since its transmission area is divided into several transmission ratio sections, it is stepless only within the specified transmission section. Therefore, AT is actually an automatic transmission between stepped and continuously variable.
The advantage of AT is that it does not require a clutch to shift gears, the gear changes are less frequent, and the connection is smooth, so it is easy to operate, which not only brings convenience to the driver, but also brings comfort to the passengers. However, there are many shortcomings. First, it responds slowly to speed changes and is not as sensitive as manual transmission, so many car enthusiasts like to drive manual transmission. Second, it is uneconomical to consume fuel, has low transmission efficiency and limited torque range. In recent years, electronic control technology has been introduced. Problems in this area have been improved; third, the mechanism is complex and repair is difficult. The hydraulic oil circulating at high speed in the torque converter will generate high temperatures, so designated high-temperature-resistant hydraulic oil must be used. In addition, if the car cannot be started due to lack of battery power, it cannot be started by pushing a cart or trailer. If hauling a faulty vehicle, be sure to keep the drive wheels off the ground to protect the automatic transmission gear from damage.