自动挡汽车

自动挡汽车 Automatic transmission control type transmission ratio selection and shift is automatic, the so-called "automatic", refers to the mechanical transmission of each gear shift is realized with the implementation of components reflect the signal system of engine load and speed control system of the shift. The driver only needs to operate the accelerator pedal to control the speed. Automatic cars can automatically change speed according to road conditions, so drivers can watch the road traffic all the time without being confused by shifting gears. There are three types of automatic transmission, which are hydraulic automatic transmission (AT), mechanical stepless automatic transmission (CVT), automatic transmission (AMT). About AT (hydraulic automatic transmission) Compared with the manual transmission, the hydraulic automatic transmission (AT) is very different in structure and use. The manual transmission is mainly composed of gear and shaft speed and torque generated by different gear combinations, AT is composed of hydraulic torque converter, gear and hydraulic control system components, through the hydraulic transmission and gear combination to achieve variable speed torque. But because of various auxiliary automatic shift mechanism can meet the needs of a variety of driving, such as parking, back, so in the automatic intervention device is also arranged on the manual lever, mark P (parking) and R (file), N (neutral), D (forward), the other is in forward also with the "2" and "1" additional file, to start or on slopes with. Since the speed change zone is divided into a number of variable speed sections, and is only stepless within the specified speed change section, the AT is actually an automatic transmission between the stage and the stepless. AT advantages: AT no clutch, gear shift, gear less, big change, smooth connection, so easy to operate, not only to bring convenience to the driver, but also to bring comfort to the car people. The disadvantages of AT: firstly, velocity response is slow, no manual transmission is sensitive, so many people love to open car manual transmission car. The second is the cost of oil, low transmission efficiency and torque range is limited, but in recent years, many models are in the automatic which introduced electronic control technology, this problem has been enhanced, but still less than the manual economy. Third is complex, difficult to repair. In the hydraulic torque converter, high speed hydraulic oil flow can produce high temperature, so use the specified high temperature of hydraulic oil, which is usually called "wave box oil", also if the car can't start because the battery power shortage, cannot start with method of cart or trailer. If the fault haulage car, but also pay attention to driving wheels off the ground, to protect the automatic gearbox from damage. About CVT (mechanical stepless automatic transmission) Honda fit now, there are some other models used above CVT gearbox. He used the drive belt and the variable groove width of the ratchet power transmission, namely when the ratchet groove width changes, corresponding changes in the driving wheel and driven wheel drive with the contact radius of transmission, transmission belt with rubber belt, metal belt and metal chain etc.. The CVT belongs to a truly continuously variable transmission. CVT advantages: light weight, small size, less parts, compared with AT, has higher operating efficiency, low fuel consumption. The disadvantages of CVT: the drive belt is easily damaged, can't bear the heavy load, is not currently used in large displacement vehicles, commonly used in 2 litres of the following models, such as Audi Multitronic, Honda CVT, Fiat Speedgear. About AMT (electronically controlled mechanical automatic transmission) Under the condition of the same transmission structure, AMT realizes the automation of gear shift by adding an automatic control system controlled by microcomputer. So the AMT is actually done by a robotic system that operates the two actions of the clutch and the gear shift. The current hand integrated automatic archives are basically this type, Chery's QQ has AMT models. About hand transmission Manual transmission integrated at present there are 3 main types: the first is the automatic transmission technology as the foundation; second is a combination of common "H" mode shift manual transmission and automatic clutch; third with manual gearbox based on the automatic clutch electronic control and hydraulic sequential shift combination. The manual transmission only has two pedals, the brake and the accelerator. The shift process is controlled by an electronic hydraulic valve, and the driver may choose between manual and full automatic shift modes. In automatic mode, transmission processor time monitors many parameters, such as mobile, speed, speed, acceleration, steering and brake pedal signal of the engine, and the engine temperature etc.. Every short instant, it will find a matching program from the stored program of the system according to the driver's operating state, and then automatically adjust the gear of the car. In manual mode, you can turn in the keys or levers of manual operation on the disc to control acceleration and deceleration gear, such as the Mondeo type F1 direction shift, feel very cool. The characteristics of manual automatic transmission The first is based on the above automatic transmission with electronic and hydraulic control device, even in manual mode automatic transmission system is still in a state of control at any time, if you forget to add the file it will help you to do it, if you will not hang into the low execution speed very quickly; it will automatically start the gears into 1 or 2; when the vehicle skidding it will automatically switch to "malignant weather pattern" to prevent wheel slippage. Such as Porsche, Audi, BMW, optional Tiptronic system Steptronic system and Q system with Alfa Romeo of this type are different between them only mode of operation. Such as Porsche, Audi can use the buttons on the steering wheel and gear, the gear lever can also be manually modified profile; Q system of BMW Steptronic and Alpha Romeo is only the shift lever modified profile. This type of transmission costs a lot, but the manual shift response is not fast. Second types of speed change systems, which combine manual transmission with automatic clutch in the ordinary "H" shift mode. Its purpose is to automate the clutch without changing the conventional manual transmission to the conventional gear shift mechanism. For example, Renault's Easy, System, Saab's Sensonic, Fiat's Seicento city automation system, and Mercedes Benz A-class cars have adopted this technology. The speed change system is simple in structure, that is, the clutch pedal is replaced by an electric motor, which will press the hydraulic system according to the instructions of the microprocessor, so that the clutch can be separated and joined. The sensors will sense the gear, the speed of the car, the position of the accelerator, and whether the driver should change gears or so on. When people only need to start driving gear, throttle on the line, the shift according to common practice, when the gears lift the throttle, the system will automatically be separated from the clutch. The system has been monitoring the speed of the vehicle and the speed of the engine. The computer can prevent the out of gear or downshift. Sometimes, if necessary, the driver is reminded to choose a lower gear. In the domestic models, the Alto "automatic clutch" was also used this technique for love not step on the clutch is a good friend. The third is a manual gearbox based on the electro hydraulic automatic clutch and shift the order together, SMG and Reynolds BMW BVR belong to this category, Ferrari F355 F1, Alpha Romeo's 156 "double spark" also has this system, the principle and the car on their. The difference is that the transmission and clutch assembly are not sequential in design. They are combinations of traditional manual transmission and electronic gear selection. How to buy an automatic sedan When selling automatic cars, many vendors advertise their products as "intelligent"". That is to say in the process of driving the driver only needs to control the accelerator pedal, the transmission will use the computer into different gear automatic control according to the change of the engine load, solar term door opening size and speed. At the same time, it can also recognize the automatic change mode of the road surface, shift gears, and automatically learn the driving habits of drivers to prevent misoperation. Here are some places that consumers of automatic cars can easily ignore: 1, structural differences: the current domestic automatic cars are intelligent, from Jetta, Beverly, until the high-end automatic transmission models, their automatic transmission is relatively new. However, the German automatic transmission focuses on durability, the structure is not too complex, the probability of failure is low, and the French automatic transmission functions more complex structure, relatively complex maintenance. 2, the difference between design: take the Jetta and Fukang, Jetta "Urban Pioneer" uses straight baffle, shift down straight push rod can be manipulated, and Beverly 988 "leader" is used to shift the distribution of ladder shaped track, P, R, N, D, 3, 2 a total of 6 stalls a, the utility model has the advantages of clear feeling, but because the lateral motion of this design than straight through increased lever, happen to death in the actual operation, many automobile manufacturing enterprises and give up the design, now foreign latest with automatic transmission cars, such as Mercedes BMW, S600, S320 Volvo, S80, Audi, A6, TOYOTA Camry Passat B5 is used through type design. 3, gear display: some automatic cars will increase a LCD display on the dashboard, car during driving gear and display in the above, and many "low-end" automatic car without the screen. Of course， It is not important for skilled drivers to show, but it is necessary for the first contact with the automatic transmission to display on the dashboard. 4, driving difference: when purchasing automatic car, the principle is convenient operation, the more "fool" the better. The more patterns, the more likely to drive according to the driver's wishes, for example, some cars with "S" movement mode, "*" snow mode, and so on. The cars without these functions depend on the computer and use the fuzzy control to automatically change the driving mode according to the driving situation. 5, whether the whole car intelligent: automatic transmission is not just a transmission, the real intelligent automatic file should look at the overall match. The real "intelligent" automatic car should be gearbox, engine and ABS system automatic connection rather than by manual adjustment, do all digital control, power, speed and braking three-in-one, greatly improving the car's power, safety and economy. 6, reliability: when we buy a car, should let the seller to you personally test drive, to see what brand, which kind of automatic transmission is more suitable for yourself. You can also consult a friend who has bought a car, so you'd better try it. D files go all out of the world Many consumers in the purchase of automatic thought hang forward is all about, this is what we called "D file to go in the world, but also have a lot of friends drove up enough automatic reaction," meaning "in the overall performance is slightly inferior to a car with a manual transmission. In fact, the chief culprit in this is "D files go the world". We will see in the understanding of the working principle of the automatic gear design, automatic transmission will make D gear according to the automatic speed in 3-2 (4 or 3 speed automatic gear car) or 4-3-2 (5 speed automatic gear automatic transform). If it is in the city slowly under the condition of automatic transmission will change continuously in 3-2, 2-3 file, manual car is can be controlled by a driver in the maximum torque output gear, automatic transmission car frequently on under shifting action would make people feel soft driving car. There are two ways we can change this situation: The first one is to start with a big gas without taking into account the fuel consumption. Most automatic cars now have learning capability. If you step on the accelerator pedal, the gear will change the shift point automatically. If the original setting is 2500 rpm, the throttle will turn up at 4000 rpm or more so that the actual torque of the vehicle is much larger than before, and the power of the vehicle is stronger. If you often use the throttle, automatic transmission program will remember your driving habits, automatic transmission shift points will change the factory when both power and energy saving settings, automatic promotion stall point of the speed of the engine, and if your car has the motion mode, select the motion mode of driving, there will be the same effect. The second way is to give up "D files go world", after all, now the automatic car model, in addition to D files, there are 1, 2, 3 files. Urban speed is not fast, you can put stalls in the 2 or 3 stalls, mountain road is placed in the 2 or 1 stalls, you will find that the car's driving force has suddenly improved a lot. This will not only adversely affect the speed change system, but will also make fuel consumption more economical and reduce the phenomenon of engine carbon deposition. Automatic car driving in urban areas, if the speed is not more than 60 kilometers, then you can use a file below the D file; when the speed of more than 60 can use the D file running, not only fuel but also no loss of acceleration; driving on mountain roads is according to the use of 2 or 1 files, in addition to maintain strong torque output, engine braking effect can avoid excessive use of foot brake, so as to ensure the traffic safety. Because the automatic car D file is not available in the engine brake function, it will only increase with the downhill speed continues to shift speed, the speed faster and faster, can only use the foot brake to control the speed, it is easy to use excessive heat generated due to brake and brake failure, thus driving the car with automatic transmission go a long downhill, D must not be running. Several misunderstandings of using automatic transmission Mistake 1 when the automatic transmission vehicle stops for a long time, the gear lever still hangs in the D gear Vehicles equipped with automatic transmissions wait to pass through signals or traffic jams. Some drivers often keep the gear shift in the D block and at the same time push down the brake pedal, which is permissible if the time is short. But if the parking time is long, had better change into the N gear (neutral), and tightens the parking brake. Because of the shift lever in the D gear, automatic transmission cars are generally weak forward, if long time press the brake pedal is forced to stop this advancement, the transmission of high oil temperature, oil is easy to deteriorate, especially in the air-conditioning system, the engine idle speed is higher in the case of more unfavorable. Mistake 2 when the automatic transmission vehicle runs at high speed or downhill, shift the gear lever in the N gear slide Some drivers, in order to save fuel, move the shift lever to the N block at high speed or downhill, which is likely to burn out the transmission. Because the transmission output shaft speed is very high, and the engine idling, transmission oil pump oil supply shortage, lubricant deterioration, but also on the internal multi plate clutch transmission, although the power has been cut off, but the passive film in wheel driven by high-speed operation, engine driven drive plate speed is very low, the two gap is small, easy to cause the resonance and slipping phenomenon, have adverse consequences. The slope needed to slide, the shift lever can be maintained in D sliding block, but can not make the engine flameout. Error 3 start the engine at the automatic transmission P or N gear Some drivers block gears outside the P or N to start the engine. Although the engine doesn't work (because chain protection can only start in the P and N gear), it may burn out the neutral start switch of the transmission. Because the automatic transmission is equipped with neutral start switch, so that the transmission can only be in the P or N gear to start the engine, to avoid other gear in the wrong start, so that the car immediately began to move forward. Therefore, before starting the engine, make sure that the shift lever is in the P or N gear. Error 4 equipment for automatic transmissions or three yuan catalytic converters for automotive propulsion vehicles to start engines Cars equipped with automatic transmission and three yuan catalytic converters cannot start because the battery is out of power, It is very wrong to start with a man or other vehicle. Because the above method is unable to transfer power to the engine, it will damage the three yuan catalytic converter. Error 5 automatic transmission vehicle ramp parking does not use parking brake When the car with automatic transmission stops on the slope, some drivers use only the P gear instead of the parking brake, which can easily lead to accidents. Because although the parking locking mechanism with the automatic transmission car in the P gear is rarely ineffective, it will cause accidents if it fails. Therefore, the parking brake should be used when the ramp stops.