Flywheel: uniformity and reliability of the engine
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Flywheel: uniformity and reliability of the engine

The internal combustion engine today remains the most efficient power unit in cars. With this unit, you can overcome any distance and enjoy the journey without spending a lot of time refueling the fuel tank.

However, to start the motor and ensure smooth acceleration, it must have a special part. This is a flywheel. Consider why it is needed in the engine, what types of flywheels are, as well as how to operate it correctly so that it does not fail prematurely.

What is a car engine flywheel?

If simple, then the engine flywheel is a gear disc. It is fixed at one end of the crankshaft. This part connects the motor and the transmission of a car. So that the torque is smoothly transmitted to the corresponding gearbox speed, a clutch basket is installed between the mechanisms. It presses the clutch disc to the elements of the flywheel, which allows you to transfer torque from the motor to the drive shaft of the box.

Flywheel: uniformity and reliability of the engine

The principle of operation of the engine flywheel

The flywheel is fixed on the crankshaft in close proximity to the main bearing. Depending on the design of the disc, it compensates for vibration during the rotation of the crank mechanism. Many modern flywheels are equipped with a spring mechanism that acts as a damper when the engine jerks.

Flywheel: uniformity and reliability of the engine

When the engine is at rest, the flywheel is used to crank the crankshaft. In this case, it works on the principle of a manual starter of old cars (a manual lever was inserted into a special hole in the motor, which allowed the driver to crank the crankshaft and start the engine).

Flywheel design

Most flywheels are not complex structures. In many cars, this is a solid weighty disc with teeth on the end. It is attached to the flange of the shank of the crankshaft using bolts.

Flywheel: uniformity and reliability of the engine

With an increase in the power of power units and an increase in their maximum revolutions, the need arose to create modernized parts that already have a complex structure. They can safely be called a damper mechanism, and not an ordinary part.

The role and place of the flywheel in the engine

Depending on the design, in addition to the drive function for the transmission, the flywheel also plays other roles:

  • Softening vibrations during uneven rotation. Manufacturers seek to distribute the cycle time in the ICE cylinders so that the crankshaft rotates with minimal jerks. Despite this, torsional vibrations are still present (the fewer pistons in the motor, the sharper the vibration). A modern flywheel should dampen such vibrations as much as possible to prevent quick gearbox wear. For this, in its design there are several springs of different stiffness. They provide a smooth increase in effort even with a sharp operation of the unit.
  • Transmission of torque from the motor to the drive shaft of the gearbox. This process is ensured by the clutch basket. In it, the driven disk with the clamping mechanism is tightly fixed to the friction surface of the flywheel.
  • It provides torque transmission from the starter to the crankshaft when the engine starts. For this purpose, the flywheel crown is equipped with teeth that the starter gear engages.
  • Damper modifications provide an inertial force for decoupling the crank mechanism. This allows you to smoothly remove the pistons from the dead points (top or bottom).
Flywheel: uniformity and reliability of the engine

Often flywheels are made quite weighty, so they are able to accumulate a small amount of kinetic energy when the expansion stroke is performed in the cylinder. This element returns this energy back to the crankshaft, which facilitates the work of the remaining three measures (suction, compression and release).

Flywheel Varieties

As already mentioned, in old cars, the flywheel was made of a cast-iron disk, on the end of which a gear rim was pressed. With the development of the automotive industry and an increase in the power characteristics of power units, new flywheels have been developed that differ from each other in efficiency.

Of all species, three are distinguished:

  • Single-mass;
  • Two-mass;
  • Lightweight.

Single Mass Flywheels

Most internal combustion engines are equipped with just such a modification of the flywheels. Basically, such parts are made of cast iron or steel. There is a large hole at the place of attachment to the crankshaft shank, and mounting holes for mounting bolts are made around the housing around it. With their help, the part is firmly fixed on the flange near the main bearing.

Flywheel: uniformity and reliability of the engine

From the outside, a platform has been made for the contact of the drive clutch disc (friction surface). The crown at the end of the part is used only if the engine starts.

During the manufacturing process at the factory, such discs are balanced to eliminate additional vibrations during the operation of the mechanism. Balance is achieved by removing part of the metal from the surface of the part (most often a corresponding hole is drilled in it).

Two-mass flywheels

A dual-mass or damper flywheel is more complex. Each manufacturer is trying to improve the effectiveness of such modifications, which is why the design of different models may vary. The main elements in such mechanisms are:

  • Driven disk. A gear ring is fixed on it.
  • Master drive. It is mounted on the crankshaft flange.
  • Torsional vibration dampers. They are located between two disks and are made in the form of steel springs of different stiffness.
  • Gears. These elements are installed in more complex flywheels. They perform the function of planetary gears.
Flywheel: uniformity and reliability of the engine

Such modifications are much more expensive than classic solid flywheels. Nevertheless, they facilitate the operation of the transmission (ensure maximum smoothness) and prevent its wear due to shocks and fluctuations during the movement of the car.

Lightweight flywheels

The lightweight flywheel is a type of single-mass counterpart. The only difference between these parts is their shape. To reduce weight, a part of the metal is removed from the main surface of the disk at the plant.

Flywheel: uniformity and reliability of the engine

Such flywheels are used for tuning cars. Thanks to the lower weight of the disc, it is easier for the motor to reach its maximum speed. However, such an upgrade is always carried out along with other manipulations with the engine and transmission.

Under normal conditions, such elements are not installed, as they slightly destabilize the motor. At higher speeds, this is not so noticeable, but at low speeds, serious problems and inconveniences can arise.

Handwheel operation and possible malfunctions

By and large, the flywheel is one of the most reliable engine components. Most often, its working resource is identical to the resource of the power unit. Depending on the material and the manufacturer, these parts are maintained 350 thousand kilometers or more.

The most problematic part of the flywheel is the teeth on the crown. The resource of this element depends on the health of the starter. Tooth from frequent use of the starter can break or simply wear out. If such a breakdown occurs, then you can buy a new crown and install instead of the old one. In this case, the entire disk must be removed from the engine, and after repair is installed back, only with the use of new bolts.

Flywheel: uniformity and reliability of the engine

Another common flywheel failure is overheating of the friction surface. Usually this happens during the improper operation of the car, associated with a violation of the rules of gear shifting (for example, the clutch pedal is not fully squeezed).

Due to overheating, the disc may become deformed or cracks may appear on it. One symptom of such a malfunction is a constant beating of the clutch in a certain speed range. It is also accompanied by strong vibration. If the driver burned the clutch and was immediately replaced with a new one, there is no need to change the flywheel.

Two-mass models fail a little more often, since their design has more additional parts. A spring may break, a lubricant may leak, or the bearing may fail (this is extremely rare, but occurs in this list).

Flywheel: uniformity and reliability of the engine

Another reason for the wear of the flywheel is the untimely replacement of the friction clutch disc. In this case, rivets will scratch the surface of the part, the consequences of which are not eliminated by anything, only by replacing the part.

Driving behavior can also affect the resource of the flywheel. For example, if at a long distance the driver drives a car with reduced speed, the vibration from the unit is amplified, which can damage the flywheel fasteners. Some motorists start and stop the engine without squeezing the clutch pedal.

Flywheel: uniformity and reliability of the engine

The flywheel is not separately serviced. Basically, this procedure is done during clutch replacement. In this case, a visual inspection of the part is carried out. In the absence of defects, nothing is done. If a grinding sound is heard, it is imperative to tow the machine to the service station so that a worn friction disc does not scratch the surface of the flywheel.

Is it possible to repair and restore a flywheel?

This question most often concerns two-mass flywheels. If a continuous modification fails, it is only changed to a new one. The standard part is not very expensive to ask such a question.

However, expensive damper modifications often cause such reasoning. Some experts grind the friction surface to remove scratches due to a worn clutch disc. In most cases, such a repair does not bring the desired result. A thin friction surface from high loads can burst, which will entail not only a replacement of the flywheel, but also clutch repair.

Flywheel: uniformity and reliability of the engine

Some cooperative service stations offer to repair an expensive flywheel for a moderate fee. However, this is also a dubious procedure. The fact is that, apart from the crown, not a single flywheel component is sold separately. For this reason, such "restoration" work is of a dubious nature.

In conclusion, it is worth paying attention that with careful use of the clutch and a measured driving style, there will be no problems with the flywheel. If the machine is rarely used, then you can think about installing a damper flywheel. In other cases, solid analogues will be more reliable.

Questions and answers:

What is a flywheel for in an internal combustion engine? This disc, fixed on the crankshaft, provides inertial force (smooths out the uneven rotation of the shaft), makes it possible to start the engine (the crown at the end) and transmits the torque to the gearbox.

What is a car flywheel? This is a disc that is attached to the engine crankshaft. Depending on the modification, the flywheel can be single-mass (solid disc) or dual-mass (two parts with springs between them).

How long does a flywheel last? It depends on the operating conditions of the car. A single-mass one often serves as long as the internal combustion engine itself. The two-mass version takes care of an average of 150-200 thousand kilometers.

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