Understanding 4 Common Car Transmission Systems
About 30 years back, it was easier to choose between the two types of transmissions available in the market. Cars usually came with manual or automatic transmissions. People who preferred, fuel economy, performance or driving pleasure, preferred to go with manual transmission, while the rest preferred to go for automatic transmissions.
Nowadays, cars come with different transmission, like CVTs, double clutch, Lineartronics, and there are many other marketing names. Even though the names of modern transmissions seem too overwhelming, their functions are pretty straight forward. There are four types of transmissions:
This is the simplest and the oldest type of transmission. It’s often referred to as Stick shift. This gearbox uses a clutch to connect the engine’s rotational energy to the transmission shaft of the car. The clutch is controlled by the driver’s foot. A fixed set of gears are engaged using a gear selector fork and Syncro which are connected to the shifter. The shifter is basically the shifting stick, which is controlled by the driver’s hand.
To change gears, the driver presses the clutch with his foot, this detaches the clutch from the engine, allowing the engine to spin. The engine, transmission and wheels of the car spin at different speeds. After selecting a gear ratio by using the stick, the driver connects the engine, transmission and wheels together again by releasing the clutch pedal.
Synchromesh gears and hill start assistance have made it easy to shift gears over the years. Synchromesh gears have eliminated the need to double declutch. Hill start assist is a recent development that prevents a manual car from rolling backwards on an incline during standing start. It keeps the brakes active for a few seconds after the brake pedal is released; this gives the driver some time to press the clutch and accelerator.
Manual transmissions are less complex in design and are less expensive to repair than other transmission types.
In Pakistan, the percentage of manual cars is gradually reducing. The manual transmission is becoming an endangered species, in cars. Many car drivers today, hardly know how to drive a manual transmission. Car enthusiasts prefer manual transmissions even today, as they give better performance, fuel efficiency and a better driving experience. Besides, there is nothing better than feeling a perfectly timed gear shift.
Automatic transmission uses a highly complex torque converter, which transfers the engine’s rotational energy. The gear shifts are controlled by the car’s computer, the gears are engaged by a universal gear set and a series of clutches and brakes. Although the mechanism of the automatic transmission is quite complex, operating it is quite easy. All the driver needs to do is to select from P-R-N-D-L. Automatic transmissions cars are expensive to repair, due to their complexity. Most automatic cars can’t match the performance and fuel efficiency of manual transmission cars.
Continuously Variable Transmission (CVT)
The driving experience of a CVT and an automatic transmission are quite similar. Though the mechanism with which CVT operates is completely different from automatic transmission. CVT doesn’t have gears at all, instead the system uses belts and pulleys to produce an infinite range of gear ratios. The car’s computer adjusts the pulleys to create the optimal ratio for the particular driving situation. This mechanism makes CVT fuel efficient. CVTs are less complex than automatic transmissions and are fairly less expensive to repair and are less prone to failure.
Most modern cars and hybrids come with CVT, some CVT cars in Pakistan are Honda Vezel. Cars like Toyota Prius come with HSD (Hybrid Synergy Drive) transmission which is like a CVT. Toyota describes cars equipped with HSD as having an e-CVT (electronic continuously variable transmission). Most car enthusiast would say the only drawback of CVT is its driving experience. Since there are no gearshifts, the car smoothly and seamlessly accelerates. True driving enthusiasts may feel he or she is operating an appliance instead of a car. Other than that CVT is one of the best transmissions out there.
Semi-Automatic and Dual-Clutch Transmission
This type of transmission is an automatic and a manual transmission. A semi-automatic transmission system uses a system of pneumatics and actuators to change gears. In a dual-clutch transmission (DCT), there are separate clutches for high and low gears, this makes shifting very fast. These gearboxes can be operated in automatic mode or manual mode. Gears can be manually shifted using paddles on the steering wheel.
This transmission type offers great performance with quick gear shift, which manual transmissions can’t match. This gearbox is mostly found in high end sports cars that are quite expensive. The only disadvantage of this transmission is its complexity and high maintenance cost.