The main purpose of the clutch system is to isolate the movement of the engine from the wheels while driving a changing gears. Thanks to the clutch, we can achieve the correct transmission of the engine power from the gearbox, which is then transferred to the vehicle’s wheels.
In this Frenkit post we explain the different types of clutches that exist on the market, all of them different from each other but with the same purpose. Here we tell you all about them, you can’t miss them!
Types of clutches in cars
The clutch system is mainly a part of the clutch system of cars that are equipped with gearboxes. As mentioned in previous posts, the clutch in a car “allows the correct transmission of power from the engine to the gearbox, which then passes to the wheels of the car”.
Depending on the characteristics of each vehicle model, we can distinguish between different kinds of clutches. For example, we can distinguish the clutch system according to the discs, which can be hydraulic, single-disc, bi-disc or multi-disc; by the type of cooling there are dry clutches or wet clutches; or the type of control, which are divided into friction, electromagnetic or hydraulic clutches, among others.
In the following, we will detail the different types of clutch actuators that we have mentioned above and that are available on the market. Each of them has its own characteristics.
According to the discs
- Hydraulic clutch. For this type of clutch to work properly, it is necessary for the hydraulic fluid to be actuated. For this reason, the hydraulic clutch does not have discs, as the power required to drive the vehicle is generated by a turbine that is driven by the rotation of the car’s engine. In particular, this type of clutch is not used, due to its high fuel consumption and the high cost of keeping the car in tune. However, it is a type of clutch that can be seen in industrial vehicles.
- Single-disc clutch. This type of clutch is called a single-disc clutch because it has only one disc between the engine flywheel and the pressure plate.
- Bi-disc clutch. In this case, this clutch model has two dics in order to properly transmit the power from the engine to the gearbox. The two-plate clutch system can be found in cars that tend to generate quite a lot of power.
- Multi-disc clutch. This model of clutch is composed of a series of friction discs that are responsible for controlling the transmission of power in the car. The multi-disc clutch can be found in motorbikes, for example.
According to the type of cooling
Dry clutch. Depending on the type of cooling of the clutch system we can find that the cooling is air-cooled, in the case of the dry clutch.
Wet clutch. When the cooling is by oil, we are talking about a wet clutch type.
According to the type of control
Friction clutch. This model of clutch is the most common on cars in circulation. In terms of operation, the friction clutch consists of the flywheel, which is supported on the primary shaft of the gearbox by a bronze bushing. In addition, depending on its type of cooling, the friction clutch is oil-cooled.
Hydraulic clutch. This type of clutch system allows the engine to transmit torque when it reaches a certain engine speed. Thus, the power is transmitted by a centrifugal pump which communicates with a turbine.
Electromagnetic clutch. Also known as an electric power-assisted clutch, it works on the electromagnet principle, i.e. an electromagnetic field is generated by an iron core and a coil for torque transmission.
Parts of the clutch system
The clutch system consists of a number of elements that make up a complete gear in which the clutch pedal and the gear lever are the two parts at a glance. In terms of clutch parts, we will describe the most common type, the friction clutch. We can highlight the following:
Flywheel. This flat circular part rotates whenever the engine is started. The flywheel, being bolted to the crankshaft (the base component on which the combustion engine is built), rotates with the engine.
Pressure plate or hub. Bolted to the flywheel, the hub or pressure plate is responsible for rotating in unison. It also consists of a diaphragm or springs, with which the clutch disc is released.
Friction disc or clutch disc. Composed of two sides to brake pads, the friction or clutch disc is coupled to the gearbox with the help of a shaft. When the clutch pedal is released, it rotates together with the flywheel and the hub. When the pedal is depressed, the friction disc disengages, which interrupts the transmission to the wheels of the car.
Pusher fork. The latter is responsible for exerting pressure on the diaphragm spring of the plate and thus releasing or pressing the disc. The pusher fork moves when the clutch pedal is actuated.
Now that you know what are the different types of clutches and their parts, we encourage you to visit our blog section on the Frenkit website, where you will find everything you need to know to carry out a correct maintenance of the components of your car, such as everything about the clutch master cylinder.
Whether you are a professional in the automotive sector or if you decide to change your car’s systems yourself, at Frenkit we are brake part distributor for all vehicle ranges, both passenger cars and light vehicles.
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The internal combustion engine does indeed generate all that power, but without a clutch, there'd be no means for it to be converted into mechanical energy in order to propel the car forward. Keeping in mind that there is a wide range of engines and transmissions, it was essential for automakers to produce different types of clutches for various types of cars.
Friction Clutch
This is the most basic type of clutch and is also the most commonly used. The clutch is comprised of a release bearing, a pressure plate and a clutch plate and tends to be operated by a cable or by using hydraulics. The bearing is used to engage or disengage the flywheel and the transmission. Most cars tend to use a single plate clutch, however cars with powerful engines tend to use multiplate clutches in order to engage the transmission. Pressing the clutch pedal will disengage the transmission from the flywheel as doing so makes the bearings apply pressure to the springs on the pressure plate, in turn releasing the clutch plate.
Dry and wet clutches
Wet clutches tend to be a little more complexed. They are supplied with oil in order to keep them cool and lubricate the internals. These clutches are mostly used in machines that are high in torque figures. The heat generated from these powerful machines is what makes the oils necessary. Dry clutches however do not need any supply of lubricants or oils. Dry clutches usually tend to be single plated clutches. This in turn means that any lubrication could in fact slip the clutch due to lack of friction. Slipping in the clutch can drastically lose engine performance. This is the reason that wet clutches on the other hand tend to be multiplate clutches.
Multiplate Clutch
When a clutch has multiple plates of friction stacked one upon the other, the friction that is generated is on a much greater scale. This in turn allows it to handle a much larger torque output without sustaining any damage. The stacking of these plates enables them to fit into the same size fitment as a regular friction clutch. These clutches are mainly used for extreme high-performance motorsports such as the Formula series and the WRC respectively.
Dual Clutch mechanisms
In the premium car market segment, most cars are equipped with a dual-clutch transmission. The mechanisms comprise of using a small clutch for even gears and one large clutch for the odd ones. Due to the fast changes in gears using a DCT, they are now widely used in various types of cars such as supercars, sports cars, and even hot hatches. The fact that one clutch is engaged at all times while the other wait for input allows seamless quick shifts.
Electromagnetic and Electrohydraulic clutches
Electromagnetic clutches are usually used when there is a certain disregard for the health and life of the mechanical components that comprise the concept of shifting. This clutch setup revolves around the process of the clutch being engaged simply by proximity sensors on the shifter or the push of a button. This remote activation of the clutch comes into play through a DC current that passes through an electromagnet that in turn creates a magnetic field. These clutch systems are most common in automotive with paddle shifter systems. Pulling on any of the paddles sends an electrical signal to the clutch to disengage and engage hydraulically once shifted into the right gear. An electromagnetic clutch creates an environment where a clutch paddle is not needed at all.