why should hold the clutch when we are trying to change the gares?

Question

What happend internally when we hold the clutch

Answer 1

Why do you hold the clutch when you are changing gears?

Because a manual transmission had metal gears that move together. When u engage the clutch it allows the gear changing to smooth and there will be no grinding. Between a good clutch and synchors a manual transmission will last forever. I'm not a expert of the internals of a manual transmission, but I thought I would try to explain.

Answer 2

A clutch is a mechanism for transmitting rotation, which can be engaged and disengaged.

Vehicle clutches

There are many diferent vehicle clutch designs, but most are based on one or more friction discs, pressed tightly together or against a flywheel using springs. The friction material is very similar to the material used in brake shoes and pads and contained asbestos in the past. Also, clutches found in heavy duty applications such as trucks and competition cars use ceramic clutches that have a greatly increased friction coefficient, however these have a "grabby" action and are unsuitable for road cars. The spring pressure is released when the clutch pedal is depressed thus either pushing or pulling the diaphragm of the pressure plate, depending on type, and the friction plate is released and allowed to rotate freely.

While engaging the clutch, the engine speed may need to be increased from idle, using the manual throttle, so that the engine does not stall (although in most cars, especially diesels, there is enough power at idling speed that the car can move although fine movements with the clutch are needed). However, raising the engine speed too high will cause excessive clutch plate wear and cause a harsh, jerky start. This kind of start is desired in drag racing and other competitions, however.

[edit] Wet and dry clutches

A 'wet clutch' is immersed in a cooling lubricating fluid, which also keeps the surfaces clean and gives smoother performance and longer life. A 'dry clutch', as the name implies, is not bathed in fluid that robs it of some energy. Since the surfaces of a wet clutch can be slippery (as with a motorcycle clutch bathed in engine oil), stacking multiple clutch disks can compensate for slippage. Most Moto Guzzi and BMW motorcycles use a triple plate clutch like a car.

[edit] Clutch operation in automobiles

In a car it is operated by the left-most pedal using hydraulics or a cable connection from the pedal to the clutch mechanism. Even though the clutch may physically be located very close to the pedal, such remote means of actuation are necessary to eliminate the effect of slight engine movement, engine mountings being flexible by design. With a rigid mechanical linkage, smooth engagement would be near-impossible, because engine movement inevitably occurs as the drive is "taken up". No pressure on the pedal means that the clutch plates are engaged (driving), while depressing the pedal will disengage the clutch plates, allowing the driver to shift gears.

A manual transmission contains cogs for selecting gears. These cogs have matching teeth, called dog teeth, which means that the rotation speeds of the two parts have to match for engagement. This speed matching is achieved by a secondary clutch called a synchronizer, a device that uses frictional contact to bring the two parts to the same speed, and a locking mechanism called a blocker ring to prevent engagement of the teeth (full movement of the shift lever into gear) until the speeds are synchronized.

[edit] Non-powertrain clutches in automobiles

There are other clutches found in a car. For example, the radiator fan may have a clutch that is heat-activated. The driving and driven elements are separated by a silicone-based fluid. When the temperature is low, the fluid is thin and so the clutch slips. When the temperature is high, the fluid thickens, causing the fan to spin.

[edit] Clutch operation in motorcycles

On most motorcycles, the clutch is operated by the clutch lever, located on the left handlebar. No pressure on the lever means that the clutch plates are engaged (driving), while pulling the lever back towards the rider will disengage the clutch plates, allowing the rider to shift gears. Some cars and mopeds have a centrifugal clutch, using centrifugal forces to engage the clutch above certain rpm, see Saxomat. Racing motorcycles often use slipper clutches to eliminate the effects of engine braking.

[edit] Other clutches

A clutch may also be a device on a shaft that will "slip" when higher than normal resistance is encountered on a machine. An example of a clutch such as this may be mounted on the driving shaft of a large grass mower. The clutch will "slip" or "give" if the blades were to hit a rock, stump, or other immobile object.

Answer 3

First the clutch provides the mechanical link between your engine and the rest of your powertrain. When you depress the clutch you break this link allowing you to move up or down through the gears without "grinding" them to a pulp. Now if you are asking is "mandatory" to use your clutch? That is a whole different question. I only use my clutch when I first take off from a dead stop. After that I use a technique called "floating" the transmission. Simply put, "floating" is shifting gears using the engines RPM to match the gear speed either up or down. It is quite an easy thing to learn if take it easy. Good Luck.

Answer 4

A simple answer to your question.
A gearbox is used to vary the torque levels to mechanically advantage the engine to put the car into motion. A lower gear means high torque and low speed, but once your vehicle is moving, it requires lesser engine effort to keep it moving and moving to a higher gear reduces the torque advantag and increases speed.

When you want to change gears, there is a problem - your engine is doing a particular speed, and your car is doing a particular speed, and the gearbox is the intermediary between these two. If you try to change gears in this situation, it is like breaking a mechanical link. Anything can happen. The clutch slowly DISCONNECTS/ DISENGAGES the engine from the transmission, allowing you to freely change to a higher or lower gear. Release the clutch and it will Re-ENGAGE, transferring the power from the engine to the wheels via the gearbox

Answer 5

Simply put (tricky!)

The clutch is the link between the engine and the wheels

depressing the pedal disengages the clutch and stops the power from the engine, via the gears, turning the wheels of the car

You have to hold it down when you switch gears so that you don't grind the gears (literally cogs) together, when you depress the clutch they stop spinning because they've been disengaged- briefly unlinked from the engine

this source explains in detail (but is fairly hard to grasp)
http://www.edmunds.com/ownership/techcenter/articles/43837/article.html

phew, hope that makes sense....

Answer 6

When you hold the clutch it disengages the gears, now you apply the new location of the stick and release the clutch, this engages the new set of gears. Gear shifting operation is done.

Gear shift is held in different slots so, it will engage proper matching gear to give proper range of speed at wheels for varying engine speed.

Answer 7

We change gear when the car speed and the engine speed radically differs. When engine speed is low ,torque on the engine to drive that mass is high. To achieve efficiency of fuel economy, we reduce the torque by driving the car at optimal speed. For raising speed of the car, we press accelerator, but we know that there is a an optimum speed for each gear position. Each speed band is designed for a particular gear set to bring engine speed and car speed synchronous. But to jump from one gear to the other gear while car is in motion, we have to disengage the engine and the gear temporarily to prevent damage to the gearbox. That's why we hold the clutch

Answer 8

when you depress the clutch you are actually relieving pressure off of the flywheel. when this happens you are able to shift gears because all of the drive gears kinda float in place untill the clutch is engaged again. thats why when you step on the clutch the vehicle kinda "sighs" and just coasts, it does that because there isn't any power being transferred to the transmission, meaning that the flywheel is not engaged to the gears in the transmission. i hope that my explaining this helps some.

Answer 9

In high speed vehicles its recommended to have a clutch-plate. The function of the clutch plate is to offer smooth gearchanging without any actual damage to the engine,this is done by disconnecting the transmission from the flywheel--NMN

Answer 10

when we hold the clutch the engene gets free from friction apllied when in gear si if u change the gear wiout pressing the clutch then this causes damage to the gearbox and ultimately to ur vehicle