An automatic transmission or self-shifting transmission is a kind of motor vehicle transmission that can automatically change gear ratios as the vehicle proceeds further, liberating the person driving from having to shift gears manually.
A transmission system is the portion which links the engine to the wheels. The engine does not have the capability to speed up as the car speeds up, hence gears come into play where they match the engine speed to the speed of the wheel so that the car can be driven faster or slower than the speed of the engine.
What is automatic transmission system?
Similar to a manual system, the automatic system too has gears except that in place of conventional clutch lies an automatic mechanism known as torque converter. The torque converter helps changing the gears automatically as and when the speed of the car fluctuates. Therefore, the driver does not have to work the cutch lever to change gears.
An AT knows when to shift gears – when you’re overtaking, going uphill or downhill or attempting to accelerate. Nonetheless, you still have certain amount of control over the shifting system.
Let’s take a look at some of the driving modes and gears of the automatic transmission vehicles:
P (Park): Apart from neutral, Park is the only mode in which the vehicle can be started. It is most frequently used when you need to stop and park the car for longer periods like at home, office, shopping mall parking etc. The vehicle needs to be in complete standstill mode before using his setting. In come vehicles, the foot brake has to be pressed before moving the car out of P mode. This mode also locks the drive wheels and the engine is disengaged from them. The motor can start, warm up and leave the engine idling.
N (Neutral): Very similar to P (Park) mode except that the vehicle movement is not restricted. When you don’t want to make the extra effort of endlessly pressing on the foot brake, like in a stop and go situation, you can use The Neutral mode when the car should not be moving. In a situation where the car needs to be towed, this mode can be used. The engine can be switched on and off in N mode.
R (Reverse): The Reverse mode is used when the driver wants the vehicle to be driven backwards. The selection method of Reverse varies from vehicle to vehicle.
D (Drive): The Drive mode allows you to engage the gear which makes the vehicle move forward through the choice of available gears.
D3 or 3 (Third): Depending on the vehicle, this mode may or may not be present. The transmission when selected, limits the gear usage to the first three gears only. Generally it is used when going downhill.
D2 or 2 (Second): Again, this mode restrains the gears to the first two transmissions only. It is useful when you want to accelerate more, when you drive on snow or ice and when going downhill or climbing uphill with a heavy loaded car.
D1 or 1 or L (First or Low): Subject to the type of car 1 or L are used. When engaged, the car will run only in this gear mode. This mode should be used when towing, going uphill or downhill, if engaged otherwise, the engine will be damaged if the RPM is too high.
Other Gear Modes
These are some of the other modes found in some vehicles which are specific to some models:
S (Sport): This mode behaves similar to the D mode. The difference lies in the fact that the gear shifts up much faster, which maximises the engine power during the time of acceleration. This mode also downshifts faster than the D mode which gives maximum engine braking effect.
B (Brake): Upon selection, this mode applies engine braking, especially used when driving down a steep downhill. This reduces the driers need to apply a forceful foot brake. This mode does not downshift the gear but uses engine power to reduce pulling while driving downhill.
M, -/+: In this setting, the driver gets to manually choose whether he wants to shift the gear up or down anytime while driving. This overrides the automatic gear selection. This approach is useful when driving uphill in a fully-loaded vehicle and you suddenly need to shift gears down to accelerate the car to move more. The + setting is to shift the gear up and the – is used to shift the gear down.
W (Winter): This is a rare selection used in few cars and when used, the car goes automatically into second gear instead of first when you start moving. Winter mode is apt for using while driving on ice or snow or icy conditions to lessen the chance of wheel spinning on the surface or even losing control of the vehicle on slippery or slick surfaces.
Automatic cars are becoming increasing popular for both drivers, new and experienced. They are far easier to operate and use than manual vehicle and reduce the stress of driving around in the city. They are also suitable while going on long trips. If you are heading for the hills or towing another vehicle/boat then you need to watch out otherwise it’s a smooth drive where all you have to do is sit back, relax and enjoy the drive. These days a lot of car models whether hatchbacks, sedans, crossovers or SUVs have all come out with automatic versions to make driving a whole lot easier and enjoyable.
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