AutoMotive News

Future Developments in Automotive Transmission Systems: 1.  The CVT will gradually replace the conventional automatic transmission due to its high fuel efficiency and smooth gear shift. 2.  The technology of semi-automatic transmission systems will also be improved to perform smooth gear shift and extend the cars' lifetime, without losing fast acceleration and fuel efficiency. 3.  The torque converter with fluid coupling may be improved, or may no longer be used for cars in the future due to its low-efficiency power transfer. 4.     5. Shift-by-wire totally eliminates mechanical lever shifting, keeping both of the driver's hands on the wheel.  The clutch is used only for starting and stopping. Once the vehicle is in motion, Auto-Shift operates like an automatic transmission, with the efficiency of a manual transmission. 6. Adaptive transmission control:   ATC has also been invented by using the computer to recognize and memorize different drivers' styl...

Continuously Variable Transmissions (CVT)                CVT is an “infinite speed” transmission that can change step-less through an infinite number of effective gear ratios between maximum and minimum values. Unlike traditional automatic transmissions, continuously variable transmissions don't have a gearbox with a set number of gears, which means they don't have interlocking toothed wheels. The word gear in CVT refers to a ratio of engine shaft speed to driveshaft speed. Moreover, CVTs change this ratio without using a set of planetary gears. Different types of CVTs : 1.     Pulley-based CVTs 2.     Toroidal CVTs 3.     Hydrostatic CVTs                The most common CVT design uses a segmented metal V-belt running between two pulleys. Each pulley consists of a pair of cones that can be moved clos...

Semi-Automatic Transmission        The two most common semi-automatic transmissions are- 1.     Dual-clutch Transmission 2.     Sequential Transmission Dual Clutch Transmission:                A dual-clutch transmission, commonly abbreviated to DCT uses two clutches but has no clutch pedal. Sophisticated electronics and hydraulics control the clutches, just as they do in a standard automatic transmission. In a DCT, however, the clutches operate independently. One clutch controls the odd gears (first, third, fifth, and reverse), while the other controls the even gears (second and fourth) as shown in the figure. Using this arrangement, gears can be changed without interrupting the power flow from the engine to the transmission.                  A two-part transmission shaft is at the heart of a DCT. Unlike a conventional manual gearbox,...

Comparison between Manual & Automatic Transmission:                Both automatic transmission and manual transmission accomplish exactly the same thing, but they do it in a totally different way. Advantages of manual transmission over automatic transmission: 1. It is easier to build a strong manual transmission than an automatic one. This is because a manual system has one clutch to operate, whereas an automatic system has a number of clutch packs that function in harmony with each other. 2. Manual transmissions normally do not require active cooling, because not much power is dissipated as heat through the transmission. 3. Manual gearshifts are more fuel-efficient as compared to their automatic counterpart. Torque converter used to engage and disengage automatic gears may lose power and reduce acceleration as well as fuel economy. 4. Manual transmissions generally require less maintenance than automatic transmissions. An automatic ...

Automatic Transmission                The concept of an automatic transmission is new in India. An automatic transmission is a motor vehicle transmission that can automatically change gear ratios as the vehicle moves, freeing the driver from having to shift gears.  In this transmission system, the gears are never physically moved and are always engaged to the same gears. Automatic transmissions contain mechanical systems, hydraulic systems, electrical systems, and computer controls, all working together in perfect harmony manually. Main Components of an Automatic Transmission: 1.        Planetary Gear Sets             2.        Clutches and Bands 3.        Torque Converter 4.        Valve Body 1 .  Planetary Gear Sets  ...

Manual Transmission                The first transmission invented was the manual transmission system. A manual transmission, also known as a manual gearbox or standard transmission (informally, a "manual", "stick shift", "straight shift", or "straight drive") is a type of transmission used in motor vehicle applications. It generally uses a driver-operated clutch, typically operated by a pedal or lever, for regulating torque transfer from the internal combustion engine to the transmission, and a gear-shift, either operated by hand (as in a car) or by foot (as on a motorcycle).                 In a manual transmission, the driver needs to disengage the clutch to disconnect the power from the engine first, select the target gear, and engage the clutch again to perform the gear change. Components of Manual Transmission The diagram below shows a very simple two-speed transmission in neutral: ...

Types of Transmission System 1.       Manual Transmission 2.       Automatic Transmission 3.       Semi-automatic Transmission:- a)        Dual-clutch Transmission b)        Sequential Transmission 4.       Continuously Variable Transmission

Transmission system Introduction                       Need For a Transmission                The need for a transmission in an automobile is a consequence of the characteristics of the internal combustion engine. Engines typically operate over a range of 600 to about 7000 revolutions per minute (though this varies, and is typically less for diesel engines), while the car's wheels rotate between 0 rpm and around 1800 rpm.