Automatic transmission and transaxle (Gearbox)
The transmission and transaxle in which various speeds are obtained automatically are known as automatic transmission or transaxle (Gearbox).
Automatic transmission needs on gear change lever and clutch pedal since clutch and transmission is combined unit and works automatically.
Today automotive several different types of automatic transmission various variants of cars in the Indian market. they are -
• AMT- Automated Manual Transmission
• IMT - Intelligent Manual Transmission
• CVT-Continuously Variable Transmission.
• DCT- Duel-Clutch Transmission/Double Clutch Transmission.
• Torque converter type, Conventional Automatic Transmission.
Automated Manual Transmission (AMT)
Automated manual transmission based on a manual transmission (gearbox) but without a clutch pedal means adopted two-pedal technology. Sometimes it called clutchless manual transmission. This gearbox we could not say the fully automatic gearbox, as considered a semi-automatic gearbox the car will be handling and control it on its own. There is an option for an auto-shift or manual drive. Through all these done by gear shifting lever.
AMT gearbox initial introduced commonly used on Maruti Suzuki on their cars they called on Auto-Shift Gear. Gradually, other car manufacturers also adopted this technology for their different car variants like mid-size sport utility vehicles (SUVs) and compact SUVs, on the Indian auto market.
AMT model cars - Tata tigor, Nexon, Maruti Suzuki models S-presso, swift, cellerio Hyundai Nios, Santro, Aura, Renault kwid and much more. but in option either manual or AMT.
How does it work?
Automated manual transmission gearbox work on intelligent with sensors, a hydraulic actuator with the assist concentric slave cylinder and electronic control module or transmission control unit clutch will engage and disengaged to engine power without a clutch pedal, the clutch automatically function.
Intelligent Manual Transmission(iMT).
Intelligent Manual transmission (iMT) is a new form of gearbox become popular in the auto market in India. Nowadays this gearbox commonly using on an option basis on mid-size SUVs and compact SUV variants of cars like the Hyundai model venue, Kia Motor Sonet model adopted iMT (gearbox).
This technology comes in between manual and automatic gearbox that why it called a semi-automatic gearbox without a clutch pedal. It construction of the gearbox exactly looks like a manual gearbox, Driver will still have to manually change the gear lever using the H-pattern gear shifter lever.
Intelligent manual transmission (iMT)
function with sensors, the sensors sense gear shifting lever position then send a signal to the control unit, when the driver changes the gear shifting lever, electronic control module decide and send command to the hydraulic clutch actuator which Clutches concentric unit or concentric slave cylinder so that way clutch engages and disengages power from the engine flows without a clutch pedal. Clutch work with the help of an intelligent shift control actuator, no need to operated by driver input only keep control with the accelerator pedal for their speeds.
Automated manual transmission and intelligent manual transmission used manual gearbox. Both gearbox lightweight as compared to a truly fully automatic transmission. One special feature called creep function which helps you bumper to bumper traffic or City drive car is crawling or creeping in very low slow speeds. iMT gearbox costs about probably fifty to sixty thousand more than the manual model.
Benefits of over to manual one has :
Easy to drive
Low fuel economy
Cost-effectively
Smooth gear change
No jerk riding
Reasonable price
Fun to drive
Continuously VariableTransmission (CVT).
Continuously Variable Transmission (CVT) is a different form of the gearbox. There are no mechanical gear and shafts. It has two pulleys which are driver and driven, one pulley connects to the engine and the other connections to the output shaft (wheel side) with a flexible belt or chain connect two pulleys. The hydraulic mechanism operated with both pulleys has different diameters of pulleys simultaneously adjust the diameter of the drive pulleys get larger the other one gets smaller the variable diameter of pulleys obtained gear ratio according to that achieved the speed and torque on the various load and road condition. This result continuously shifts the gear without any input from the driver, continuously power flows from the engine to the wheels.
Continuously Variable Transmission (CVT) differ technology compared to the rest of other automatic transmissions it light weigh than another full automatic gearbox.
Benefit of CVT
Low fuel efficiency
Comfort driving
Continuously shifting gear
Eliminate jerk riding
Sleepless acceleration
Low CO2 output.
Duel/Double Clutch Transmission (DCT)
Dual-clutch transmission another multispeed gearbox that has a twin-clutch arrangement with odd and even gearset. The duel clutches mounted on the same input shaft, it has no clutch pedal. It operates an electronic control unit and the hydraulic control clutch work independently. One clutch operates the odd gears ( 1st, 3th, 5th and Reverse)while the other operates the even gears (2nd, 4th, and 6th) uses this arrangement of gear can be shift without interrupting the power flow from the transmission.
The purpose behind a DCT is to reduce the gap between gear shafts to a minimum, with the benefits being in performance and fuel efficiency. It so fast power changing hear during acceleration gear changes on DCT measured in the millisecond, faster than any driver is capable, that retain advantages no jerk ridding rest of the other automatic transmission. This result faster gear shifting without interrupting the torque flow through the driveline so it provides greater fuel economy and improving efficiency compared to other automatic transmission types.
Torque converter Conventional Automatic Transmission and Transaxle.
The transmission and transaxle truly conventional gearbox. Uses a torque converter with planetary gearsets to transfer the engine power to the gearbox. The torque converter clutch is electronically controlled but it operates hydraulically.
The torque converter is a hydraulic torque transfer device, it enables power delivery but can also decouple is operating at very low engine speed. This transmission and transaxle have one or more planetary gear sets controlled by the clutch band, one-way clutch and multiple-disc clutches. These types of gear fully control by the electronic control unit or Transmission control unit, sometimes called the powertrains control module. Sensors monitor operating conditions such as vehicle speed, engine load, and throttle position. This information is sent to the control unit then using information from various sensors input Electronic Control Module/Unit (ECM), signals are sent to eclectic shift solenoid. This resulting release of fluid pressure to the torque converter and gearbox mechanism.
The Main advantage of torque converter of automatic transmission or transaxle is:
• Simple driving control
• It can increase the high torque
• comfort and smooth driving
• Eliminate the vibration and jerk
• Fun to drive.
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