1. Introduction
2, automotive automatic classification wave
Common automotive automatic transmission, there are three types, namely, hydraulic automatic transmission (referred to as the AT), mechanical stepless automatic transmission (referred to as the CVT), Automatic Mechanical wave (referred to as AMT). Car is currently widely used AT, AT almost become synonymous with automatic wave.
automatic transmission works if you opened automatic transmission car, you know, there are two automatic transmission and manual transmission difference
Unlike the automatic transmission manually without a clutch
without shifting automatic transmission, the gear shift DRIVED the appropriated line.
automatic transmission (torque converter plus TORQUECONVERTER, some places call wet clutch) and manual transmission (plus clutch) is in a completely different way to do the same function. The position of the vehicle automatic transmission
As with the manual transmission, automatic transmission main role is to transform a large output of the engine output to the driving wheel speed range.
between manual and automatic transmission is a very important difference is that the manual transmission by different diameters locked to the output shaft gear to achieve a gear ratio change, but the automatic transmission gears with the same group different arrangement to produce different gear ratios. That is called a planetary gear set of gears.
An automatic gearbox is a planetary gear assembly with two whole composition.
Each component can be varied as an input, output, or stationary. Selecting different combinations, you can obtain different gear ratios.
so that a set of gears and no needHis gear together, you can separate the output of different gear ratios. The two sets of gears in a row can get four forward gears and one reverse gear.
torque converter (also called wet clutch) works TORQUECONVERTERS of
If you read the above discussion regarding manual transmission, you know the engine through the clutch and manual gearbox is connected . If not, then the clutch to stop, then we have to switch off the engines. But with the car automatic transmission is not clutch. It uses a torque converter.
Now we need to find out why the automatic transmission torque converter, the advantages of the working principle and the torque converter torque converter and shortcomings.
and, like manual transmission, automatic transmission car is also required when the transmission wheel and still allow the engine is still able to rotate. Clutch manual transmission is used to disconnect the engine and gearbox. Automatic transmission using a torque converter.
the torque converter between the engine and transmission
the torque converter is a fluid coupling FLUIDCOUPLING, which allows independent rotation of the engine and gearbox. If the red light in the car engine is idling engine speed is very low, the input torque of the torque converter which is very small. So long as the light foot on the brake you can let the car remain stationary.
You can try, if you look left foot to step on the accelerator, then your right foot will step on the brakes to make a little heavier car remains stationary. Because you give oil, then, the engine speed is increased, the more fluid into the torque converter, so that the output more torque to the wheels.
There are four components of the torque converter in a robust housing.
PUMP pump
TURBINE turbine
Stator STATOR
Transmission fluid TRAMISSIONFLUID
of the torque converter housing is fixed to the engine , and so it is synchronized engine speed on the flywheel. The vane pump is fixed to the housing, engine speed, and so they are synchronized. The following diagram shows how the various components are assembled together.
of the torque converter pump is a centrifugal pump. When it turns to put the liquidThrown out. When the center of the outwardly thrown liquid produces a vacuum so that you can inhale more liquid.
of liquid into the turbine blades and associated gearbox, so that the turbine rotates to push the transmission. So the car began to run forward.
In addition to not let off the engine to stop other than the automobile, the torque converter is in fact larger output torque when the vehicle acceleration from standstill. Modern torque converter capable of amplifying the engine torque is two to three times. When the engine rotational speed faster than the rotation of the transmission output torque converter can be larger than the engine torque.
at a high speed, the speed of transmission can gradually catch up to the speed of the engine. The final speed of the two is very close. Of course, preferably the same, because of their different rotational speed, then there is an energy loss. This is one of the reasons why the automatic transmission to be gas-guzzling vehicles than the manual.
To solve this problem, there is a lockup clutch torque converter on the CLUTCH LOCKUP material on some cars. When the two halves of similar speed torque converter lockup clutch to put up with them, so that there is no slippage between them. Improve the transmission efficiency.
3, hydraulic automatic wave
4, stepless automatic mechanical wave
and the CVT Ratchet variable groove width of the drive belt for power transmission, i.e. when the ratchet groove width changes elbow, to change the contact radius corresponding drive wheel driven wheel drive belt variable speed, the drive belt generally with a rubber band, metal band, and metal chain. CVT is true of the stepless, it has the advantage of light weight, small size, fewer parts, and has a high AT comparison operating efficiency, low fuel consumption. But the disadvantage is also obvious CVT, the belt is easily damaged, can not bear a greater load, can only be restricted to about 1 liter automotive low power and low torque, and therefore the automatic transmission in the percentage share of about 4 or less .
5, Automatic Mechanical waves
in the AMT transformation (manual transmission) on the basis of the original mechanical transmission, mainly the manual shift control portion. I.e. robotic system in the case of a constant overall transmission structure controlled by the microprocessor to automate the installation shift. Thus AMT is actually done by a robotic system for operating the clutch and the selected gear of two actions. Since the AMT can be modified in the manual transmission is the production base on the good production inheritance, with responsibility for investment is also low, likely to be accepted production plant. AMT’s core technology is computer-controlled, electronic technology and quality will directly determine the quality of the performance and operation of the AMT. It is reported that the wave of the future automotive automatic localization will focus on the development of AMT.
Accord shift lever of the automatic transmission has seven gear, is divided into “P (parking)”, “R & lt (Reverse)”, “N (Neutral)”, “1”, “2 “,” D3 “,” D4 “.
When the P range position, the transmission is mechanically locked in this blocking the car, preferably the brake pedal, the starter to avoid increasing the load, when the block P out, the brake pedal must press release lever shift operation button.
R blocking operation, must ensure that the vehicle can not move forward, if it is traveling forward in a parked car so that the brake must re-enter the R range, to avoid damage to shift gears.
N block is neutral, waiting in the parking short, regardless of whether the car is off, you can use the N block, but left the car better to use P block. When the N-range to the other range transducer, must brake pedal, transmission gear to prevent injury.
D4 block for the driving gear, this gear during normal driving, the transmission based on the vehicle speed and acceleration, automatically select the appropriate gear, conversion between 1-4 (or 5) forward speed gears, we traffic D4 is a block-based.
D3 stopper likewise road block, three forward gears except gears converting only the first saw, the same basic block and D4, but must pay attention to the maximum speed allowed by three gear wheel while driving, to avoid damage engine. Trailer hills should be used in areas D3 block when the next block steep slopes should also use this to provide engine braking, brake pad wear and reduce heat generated by friction.
2-speed transmission is locked in a second gear wheel, even when parking is not automatically change to the first gear. When steep slopes, block 2 can provide a large power, when the steep slope, the engine braking effect is increased. In ice and snow slippery road surface or a vehicle start, stop 2 wheel spin can be reduced slippage. When
1-speed transmission is locked on the first gear wheel, this is my experience almost no blocking. When
In the automatic transmission is driving the process controlled by the computer, it can be added or subtracted from the engine speed gear and vehicle speed, rapid acceleration in the process, in order to increase the transmission power downshift will, therefore a sudden acceleration foot throttle in the end, the car seat will obviously feel about the re-acceleration, my experience is driving hard acceleration, heavy throttle to 3000 or 4000, and then step on the gas to close, let force transmission upshifts, repeated 3 to 4 times until the highest gear bit, driving stability will be much better, speed very quickly, it is still not allow the engine to high speed work.
Although computer-controlled automatic transmission shift, but the shift speed based on your driving habits automatically memory. Some novice car can clearly feel the shift shock, because usually drive can not refuel, long-term work at low engine speed, resulting in the automatic transmission shifting at low speed, low-speed torque and the engine output is not enough to drive hard high gear wheels and therefore it will feel shift shock, impact and obviously the same principle ought to shift my hand when the car fast enough. The key to solving this problem is to maximize the engine speed, as far as possible Bigfoot throttle acceleration, to improve the transmission shift speed. According to my experience, to 2.4, for example, the gearbox shift at 2000 rpm or less, will feel the impact of the shift, is experiencing the lowest conversion block 1700, shift shock is very serious, hard acceleration to high speed on the car 4000 rpm, run a few rounds down, the automatic transmission speed conversion to 2500, hardly feel the shift, the tachometer needle can fall by shifting the shift has been determined, after a few days after driving by the owners themselves, 1700 resumed conversion block, helpless.
usually pay more attention to driving an automatic transmission shift change unscientific driving habits, reduce shift shock, help to reduce the transmission gear wear, driving comfort, stability will be greatly enhanced. Check the transmission fluid regularly, so that the transmission work in a good environment, but also make your car work better and more safely for you. All of the above was driven byExperience, perceptual, please Paizhuan discussed.
6, the working principle of torque converter
is currently widely used in a single stage by a duplex pump impeller, a turbine, and a stator composed of three components of the closed-car integrated torque converter. Pump and turbine are cup-shaped. Pump impeller of the torque converter housing integrally connected, is an active member; suspended in the torque converter turbine, is connected to the output shaft via a spline, the driven element; suspended between a guide wheel and the turbine impeller, by way clutch shaft and the guide sleeve fixed to the transmission housing. After
the engine start, the pump wheel driven by the crankshaft rotates, the centrifugal force generated by rotation of the working fluid along the blade between the impeller blades thrown outwardly from the inner edge of the rim; this part of the working fluid with the pump wheel having both the rotational velocity component in the circumferential direction, but also points toward the axial velocity of the turbine. The working fluid impinging on the turbine blades, the turbine driven pump wheel is rotated in the same direction.
From the turbine effluent fluid velocity v may be seen to work for liquid phase velocity component flowing out of the turbine blade surface Synthesis rotational velocity component u ω along with the turbine. When the front of the turbine speed is relatively small, the working fluid flowing out from the turbine is backward, the working fluid impact stator blade. Since the guide wheel is defined way clutch can not rotate backward, the stator vanes guide the working fluid to flow rearwardly pushed forward vane impeller, the pump impeller rotation promotion, so that the torque acting on the turbine increases.
As the rotational speed of the turbine increases, the velocity component u becomes large, when the closing speed ω u and v refers to the beginning of the back guide blades, the torque converter reaches the critical point. When the turbine speed is further increased, the impact of the working fluid back surface stator blade. Because the one-way clutch allow the stator to rotate forward together with the pump wheel, so driven by the working fluid, the direction of rotation of the guide wheel freely rotating impeller, the working fluid back to the pump wheel smoothly. When the working fluid flowing out from the turbine exactly coincides with the direction of the outlet stator blades, the torque converter torque multiplication effect does not occur (when the torque converter fluid coupling conditions referred conditions).
against the working fluid of the torque converter transmission torque, lower than the transmission efficiency of the mechanical transmission. A lockup clutch disposed in a torque converter, can be transmitted directly in the high speed operating conditions the pump and the turbine wheel are locked together, to achieve power, mentionHigh transmission efficiency of the torque converter.
7, the working principle of the planetary gear transmission
Although capable of transmitting the torque converter and the engine torque is increased, but not the torque ratio, the shift range is not wide, can not meet the work car use required conditions. To further increase the torque, to expand its transmission range, to improve the adaptability of the car, behind a torque converter and an auxiliary transmission means – a step-gear transmission. Most of the gear shifting transmission is a planetary gear.
is performed by the planetary gear elements of the planetary gear mechanism and a clutch, brake and one-way clutch and other components. The planetary gear mechanism typically consists of a plurality of planetary row. Planetary line about how much the number of files. A shift actuator
The transmission comprises a planetary gear shift clutches, brakes and one-way clutch shift control.
shift clutch is a wet multi-plate clutch, the hydraulic piston when the drive plate and the driven plate when pressed, engaging the clutch; when the working fluid is discharged from the piston cylinder, the piston return spring retracted so that clutch disengagement.
shift brakes usually two forms: one is a wet multi-plate brake which has a structure substantially the same as a wet multi-plate clutch, except for connecting a brake rotor and the transmission housing, the rotating member can not rotate. Another form of an outer shifting beam type brake band brake.
The one-way clutch and the planetary gear one-way clutch of the torque converter in the same structure.
8, automatic transmission hydraulic mechanical transmission control
Control description
Automatic hydraulic control system typically selected by a gear oil, manual adjustment parameters, the time shift control, shift quality control components.
The portion of oil selected from the throttle opening and the change lever position, the pump output hydraulic pressure is adjusted to a predetermined value, the hydraulic pressure to form a stable work.
In the pilot hydraulic automatic transmission, the parameter adjustment sectionThe main throttle valve pressure regulating valve (the throttle valve) and the speed control regulator valve (also called governor). A throttle valve for regulating the pressure of the output hydraulic pressure can reflect the size of the throttle opening degree; speed control of the output of the hydraulic pressure regulating valve is dimensioned to reflect the size of the vehicle speed.
shift timing control section for switching an oil passage leading to each of the shifting actuator (clutches and brakes), the shift control to achieve.
by a locking signal to the valve control solenoid valve, the lockup clutch in the torque converter engagement and disengagement in a timely manner.
Quality control action shift the shift process section is more stable and soft.
turn off automatic gearbox halfway how to do
car is not equipped with an automatic transmission clutch, thus avoiding the fundamental accident caused by improper operation of the engine flameout, but some automatic models due to mechanical failure, or possible way unexpected flameout. In such cases, if there is no previous case, it can be restarted without stopping.
In practice, to quickly push the shift lever into neutral (N), the ignition switch to the start (START) position, after a successful restart, then quickly pulled the lever bar D, with the normal to . If several attempts, the engine still does not start, indicating a more serious fault, then it should decisively shut down for maintenance.
Using this method, the vehicle must be familiar with the operation, if the force is too large, the shift lever is pushed directly into the reverse gear (R), would cause greater damage to the transmission, some vehicle ignition switch prevent secondary start, we must first turn back to the closed position, in order to re-start, but we must be careful not to lock the steering wheel, in addition, after the engine flameout, brake and power steering also will fail, then, need more power to control the vehicle.
all these, usually clear to everyone, but in an emergency situation, it is inevitable rush, so if a novice, would be best to get down to the car to the side of the road. Remember: At any time, a vehicle equipped with automatic transmission can not be used motoring start.
9, maintenance
1. Always check the automatic transmissionOil level is normal. Check method of automatic transmission fluid and engine oil is not the same, to check the engine oil in the cold state, the transmission oil is the oil needs to be heated to about 50 ℃, and then stays in the gear shift lever 2 seconds after the parking gear is placed, this time the oil dipstick normal should be between the highest and lowest line, such as not necessary to add the same oil quality.
2. Grasp the automatic transmission fluid replacement cycle. Automatic transmission internal control mechanism is very precise, with a small gap, so most manufacturers recommend automatic transmission oil change usually two years or 4 to 60,000 km. During normal use, the operating temperature of the transmission oil is generally about 120 degrees Celsius, so the high quality requirements of oil must also be kept clean. Secondly, the use of transmission oil grease generated after a long time, there may be the formation of sludge, it will increase the friction and wear of each plate member, but also the hydraulic system, the power transmission is affected. Dirty oil sludge will move the respective valve element in the valve body poor, and affected by the hydraulic control, so that the automatic transmission is abnormal.
3. Properly replace the gearbox oil. Presently preferred method is a dynamic oil change oil change, transmission using a dedicated cleaning equipment, in the course of transmission has been operated in the full cycle of old oil, drained and then add a new gearbox oil, so that the oil change rate up to 90 or more, to ensure good oil change effect.
4, replace the automatic transmission lubricating oil. Deepening the old equipment maintenance automatic transmission fluid and other debris was completely removed, as a percentage of the automatic transmission 49 by the lubricating oil discharged out of the automatic transmission is not possible using atmospheric pressure, and the residual oil will sludge, impurities etc. gathered at the valve body, a hydraulic torque converter and the cooling circuit, if not addressed within the system will result in a clean oil plug. So reasonable replacement automatic transmission lubricants is the key.
10, and maintenance principles
First, each of the cars traveling 50,000 km, and the power supply connected to the car, supporting the use of linker contact with a cooling tube and a transmission apparatus. Then, in the engine idling state, the automatic transmission was added clearedLotions, foot slam the brakes, replace one gear of the automatic transmission, to remove harmful substances, and then fully replace the automatic transmission apparatus by means of a fluid.
Second, blended with the automatic transmission to the automatic transmission protective agent, the addition ratio of 5 percentage of older cars automatic transmission, preferably an automatic transmission stanch agent added bottle, the seal in order to restore the transmission of aging, prevent leakage.
Third, the film deposition and the like can be completely discharged within the automatic transmission system, to avoid contamination of the new ATF fluid. Recovery and automatic transmission oil seal elastic pad, enhancing sealing performance, prevent and suppress leakage of the automatic transmission. This is also the key to automatic transmission repair, improve the performance of ATF fluid, and extend the life of ATF automatic transmission.