Transmission Systems in Automobiles
- By Suparna More, Tejas Kasawe, Vipul Shinde, Viraj Darekar, Jeevak Virkar
Introduction:
A car transmission is one of the most important components of a vehicle. It’s what moves the power from the engine to the wheels.
In order to propel the vehicle, a particular type of speed and power changing device is required to transfer the power developed by engine to the driving wheel due to constantly changing requirement demand on the engine and inherent limitation is called transmission, and this system is called transmission system.
(https://mechathon.com/automobile-transmission-system/)
Need of Transmission:
A car transmission helps to ensure that your engine spins at the right rate without going too fast or too slow for your needs. It also ensures that your wheels get the correct amount of power. Without a transmission, any automobile would be difficult to start and stop and would be utterly unreliable.
Components of transmission system:
Below are the major parts of the transmission system in an automobile engine:
· Clutch
· Gearbox
· Propeller shaft
· Universal joints
· Differential
(https://vehicledynamics.weebly.com/home/transmission-basics)
Functions OF Transmission System:
● Provide means of connection and disconnection of an engine with rest of power train without shock and smoothly.
● Provide varied leverage between the engine and the drive wheels.
● The means to transfer power in the opposite direction is provided.
● Enable power transmission at varied angles and varied lengths
● Provide means to drive the driving wheels at different speeds when required.
● Bear the effect of torque reaction, driving thrust and braking effort effectively.
How Transmission System works:
If you’ve wondered about how a transmission works, the process varies depending on the type of transmission. Whatever type of transmission it is, the answer to what does a transmission do is to enable the gear ratio between the drive wheels and engine to adjust as the car slows down and speeds up.
When a vehicle is stopped, the transmission disconnects the engine from the drive wheels so that the engine can keep idling when the wheels aren’t in motion. Transmissions also enable quick acceleration from a stop and enable the engine to run more slowly to cut down on wear while the vehicle is driving at consistent speeds.
Types of Transmission Systems:
1. Manual Transmission System
2. Automatic Transmission System
3. Semi-Automatic Transmission system
4. Continuously Variable Transmission system
1. Manual Transmission
Manual transmissions have a clutch pedal and a shifter the driver uses to manually change gears. These types of transmissions consist of a set of gears along a pair of shafts, called the input and output shafts.
How does a manual transmission work? With a manual transmission, the driver has to select the proper gear and engage or disengage the clutch. The transmission uses a flywheel, pressure plate and clutch to engage and disengage the engine from the transmission.
The flywheel and pressure plate are connected to the engine. The clutch is sandwiched between them and is splined to the transmission input shaft. The term “push in the clutch” means to release the pressure plate, which disengages the clutch from the engine. Every time you make a shift, you have to push in the clutch first.
The following are various types of manual transmissions.
(https://wikicars.org/en/Manual_Transmission)
a. Dual-Clutch
This transmission uses two clutches, which can be wet or dry. One clutch operates the even gears (2, 4 and 6). The other clutch operates the odd gears (1, 3, 5 and reverse). Dual-clutch transmissions were common in older cars and are still found in modern race cars. With today’s dual-clutch automated manual transmissions, sometimes called a double-clutch transmission or a twin-clutch transmission, a computer controls the clutch engagement and shifting, bridging the gap between a manual and automatic transmission.
(https://auto.howstuffworks.com/dual-clutch-transmission.htm)
b. Unsynchronized
The first manual transmissions were unsynchronized, or “non-synchro.” They were also called rock crushers because drivers would grind the gears together trying to get them to mesh. Trucks used this type of transmission well into the early 1960s because these transmissions were very strong.
(https://en.wikipedia.org/wiki/Non-synchronous_transmission)
c. Synchronized/Constant Mesh
Synchronized/constant mesh transmissions keep the cluster gear, drive gear and main shaft gears constantly moving. These types of transmission use pads to slow down the gears. This eliminates the need for double-clutching action.
(https://www.mechanicalbooster.com/2017/12/how-synchromesh-gearbox-works.html)
d. Single-Clutch
Single-clutch is a manual transmission with the computer controlling the shifting and clutch. Shifting and clutch control can be electric, hydraulic or electrohydraulic. The popularity of single-clutch transmissions started to fade as dual-clutches were able to handle increased torque.
(https://www.automobileinformer.com/single-plate-clutch/)
2. Automatic Transmissions
How does an automatic transmission work? The main automatic vs. manual transmission difference is that with an automatic transmission, the process that powers a manual transmission happens within the transmission itself. Automatic transmissions typically don’t use clutches. Instead, the automatic transmission relies on a torque converter to change gears.
The first automatic transmission, which was more like a semi-automatic transmission because it still had a clutch, has been around in some form since the early 1900s. The first true automatic transmission used in a production car was the Hydro-Matic, in a 1939 Oldsmobile for the 1940 model year. The inventor was Earl Avery Thompson.
Most large SUVs and trucks have traditional automatic transmissions. Here are some terms commonly associated with automatic transmissions.
(https://www.toc.edu.my/automotiveandmotorsports-hub/2006/how-automatic-transmissions-work)
3. Semi-automatic Transmission:
The automated manual transmission is just like manual transmission which also uses a mechanical clutch. But in the automated manual type of transmission, the clutch is not controlled by the driver making the clutch pedal eliminated. The clutch is automatically controlled using electronic, pneumatic or hydraulic. This transmission system is also known as “Direct Shift Gearbox DSG” or “Sequential Manual Gearbox SMG.” It features all the engagement method such as automatic forward gear shifts or manual shifts through the gear selector and the button or paddles on the steering wheel.
· Automated Manual Transmission
An automated transmission, sometimes referred to as an AMT, is a manual transmission with a computer controlling the shifting and clutch. The AMT is used in heavy-duty trucks.
4. CVT Transmissions
Continuously variable transmissions, called CVTs, are pulley-based transmissions that are primarily used in small vehicles with small engines. CVTs have been used for years in snow machines, ATVs and side-by-sides, to name a few. They’re also more recently popular in hybrid vehicles.
The basic set-up is a primary small drive and a secondary large driven clutch, with a belt or chain to connect the two. The belt or chain will sit low in the primary drive and sit high in the secondary drive at a stop.
As you accelerate, the primary drive will contract, causing the belt or chain to walk up, while at the same time the secondary will expand, causing the belt or chain to walk down.
(https://learnmech.com/continuously-variable-transmission-components-working-types/)
Conclusion:
A car transmission is a vital part of a car and helps in the transmission of power from the engine to the wheels, which helps you drive. Manual and automatic are the two types of transmission but there are different kinds of automatic transmissions like Automatic Transmission, Continuously Variable Transmission, Semi-automatic transmission, Tiptronic transmission and Dual Clutch Transmission. Automatic transmissions give convenience to the driver while a manual transmission helps the driver be more connected to the car. A manual transmission is difficult to learn and requires lots of practice due to the many driving components involved. All automatic transmissions are easier to learn due to the absence of a clutch pedal.
Thank You for reading, have a great day!