The transmission or gearbox of a car is a system that transmits power from the engine of a car to the driving wheels. There are a few different options available on the market. The most common include:
A manual transmission uses a mechanical clutch which is operated by the driver. This connects the drivetrain to the engine. When the driver wants the car to start moving, they can select the appropriate gear according to the speed of the car. When braking is required, a manual gearbox makes engine braking possible. By changing down gears, the driver slows the engine. Lower gears are used for speeding up or slowing down, higher gears are used when cruising at speed; engine revs drop and less fuel is consumed.
Manual gearboxes are generally cheaper, lighter, give better performance and have more fuel efficiency than an automatic.
An automatic transmission is a gearbox that can change gears without use of a driver operated clutch. Instead, the vehicle relies on a torque converter which is placed between the engine and transmission.
Automatics are easier to use than manuals, and are fast gaining popularity. Initially automatics had many drawbacks to them, but advancements in technology have enabled a more sophisticated automatic transmission to emerge, bringing them closer to a manual in fuel efficiency and performance.
A tiptronic is a type of automatic transmission that allows driver flexibility and control by adopting some of the advantages of a manual transmission. A tiptronic gearbox allows the driver to override the automatic mode for better control of performance. This system allows the car to operate as a sports car when on the open road, or to be driven as an automatic in congested traffic or built up urban areas.
Different manufacturers have different names for this technology. Other names you may recognize are:
- Sequential Sportshift
- Manual Shift Mode
- Sport AT
- Command Shift
- HIVEC H-Matic
Sequential Manual Gearbox
A Sequential Manual Gearbox is a transmission which allows the driver to select the gear either directly above or below the gear which is currently in use by pulling or pushing a paddle or lever.
This type of transmission is useful in high performance and racing cars as it prevents the driver from missing a gear. It can enhance speed as navigating a clutch is not requires, and gear change is possible during acceleration. In racing, an SMG allows the driver to have their hands on the steering wheel at all times, enabling full control of the car.
Other names this technology may appear under are:
- F1-Superfast (Ferrari)
- Cambiocorsa (Maserati)
- Selespeed (Alfa Romeo)
- SMG (BMW)
- SMT (Toyota)
- Continuously Variable Transmission
This type of transmission is similar to an automatic in that it doesn't require the driver to manually shift gears. It differs in that it has infinitely variable gear ratios. This means that instead of using gears, Continuously Variable Transmissions utilize a pair of variable-diameter pulleys connected by a belt or chain that can produce an infinite number of engine/wheel speed ratios. This enables seamless acceleration without the jerk or jolt associated with gear changing. Fuel efficiency can also be enjoyed with this type of technology as the engine is able to run at peak efficiency speeds within a narrow range
Until recently, the CVT has experienced difficulty integrating into the marketplace, but with advances in technology in the latest models of car this type of transmission is more user-friendly and is becoming a common alternative to the manual or automatic transmissions.