KR20090063917A - Method for controlling timing-belt tension of engine - Google Patents

Abstract

A method for adjusting tension of a timing belt of an engine is provided to minimize an increase of peak torque transmitted to a transmission by reducing a change of angular velocity through a tension control of a timing belt. Tension of a timing belt is minimized by using vacuum pressure of a variable idler while a crank shaft is rotated by a stroke of an engine. A predetermined idle rotation number is checked by the variable idler. A change of angular acceleration is checked according to the idle rotation number. The vacuum pressure of the variable idler is optimized toward an increase of the tension of the timing belt when the angular acceleration is not changed. A charging state of a battery is checked according to the change of the angular acceleration. The vacuum pressure of the variable idler is optimized to minimize the tension of the timing belt when the charging state of a battery is sufficient. The tension of the timing belt is optimized by operating the vacuum pressure of the variable idler when the charging state of the battery is insufficient.

Description

How to adjust the timing belt tension of engine accessories {Method for controlling timing-belt tension of engine}

The present invention relates to a method of adjusting the tension of a timing belt, and more particularly, to a method of adjusting the timing belt tension of an engine accessory by an active variable idler.

In general, the vehicle is driven by the power generated by the explosion stroke of the engine. To generate such power, the engine is provided with a crankshaft, a camshaft, an oil pump, and the parts are connected by a timing belt. It is.

The timing belt plays a role in transmitting the rotational force of the crankshaft to the camshaft and oil pump in the engine. However, the timing belt has the disadvantage of increasing when the timing belt ages. Therefore, an auto tensioner and an idler are installed to compensate for the timing belt tension. Is kept constant. Here, the auto tensioner serves to stably maintain the tension of the timing belt against various operating state changes of the engine.

The auto tensioner used to drive the timing belt and the serpentine belt of the engine is largely mechanical and hydraulic. The mechanical type uses a spring and a friction damper. While the price is low, belt damping is easy to occur due to low damping efficiency, and it is disadvantageous in terms of noise and durability since the initial belt mounting load needs to be increased.

Hydraulic type is to maintain the tension of the belt through the plunger by the hydraulic pressure supplied by high pressure, it is relatively advantageous in terms of noise and durability by setting the initial mounting load of the belt to be small, and to suppress the slip of the belt with high damping efficiency On the other hand, the arrangement of the engine is disadvantageous because of its high price, complicated structure and many required components.

1 is a view showing the accessory of the engine according to the prior art, Figure 2 is a view showing a drive system of the engine accessory according to the prior art.

Referring to FIG. 1, the accessory of the engine 10 according to the related art uses a damper 11, an auto tensioner 12, an overrunning alternator pulley (OAP) 13, or the like to suppress vibration of a timing belt. It is preventing.

Here, various kinds of machines that assist engine driving, such as alternators, power steering, and air conditioners, are called auxiliary machines. The engine is composed of an engine block including a cylinder with a piston moving up and down, a cylinder head part including a spark plug, a combustion chamber, and an intake and exhaust valve, an engine oil fan, and more precisely control the engine around the engine. For each sensor, various kinds of machinery and accessories to assist engine operation are attached.

As a method for preventing the shaking of the timing belt or the chain according to the prior art, there are various kinds of auto tensioners 12, among which tension adjustment by the oil pressure and the tension of the return spring, and the high pressure chamber and the low pressure chamber are It is common to adjust for sudden displacement fluctuations that exist. As another method, the one-way clutch fixed to the alternator called OAP 13 is provided to reduce the alternating charge of the alternator and to reduce the belt tremor, but there is a limit in reducing the tremor at cryogenic temperatures.

The timing belt tension using the auto tensioner 12 is a factor in the friction loss of the engine, and the auto tensioner 12 is used as an optimization operation considering fuel economy in the actual use area. However, in the case of passenger diesel engines, the low compression ratio is becoming more and more as the exhaust gas is strengthened. Accordingly, the combustion characteristics of the engine are gradually deteriorating. Furthermore, in the case of a cryogenic temperature below -20 ° C, such as winter, In addition, there is a problem in that there is a limit to reduce more friction losses by developing a minimum friction loss for improving fuel economy. Therefore, there is a need for measures to eliminate the belt shaking phenomenon of cryogenic temperature caused by belt shaking.

Referring to FIG. 2, a driving system of an engine accessory according to the prior art includes an engine accessory that operates by being powered by a crank pulley of an engine, for example, an engine accessory such as an alternator, an air conditioner compressor, and a water pump. Both are driven by using the rotational force of the crank pulley 21, the crank pulley 21 and each of the shafts 25 is mounted to the sprocket 22, the accessory 25 is transmitting power through the timing belt 23.

On the other hand, idler pulleys 24a, 24b and 24c are provided at appropriate positions between the sprockets 22 in order to enlarge the amount of contact with the timing belt 23 and prevent the belt from being separated. Such idler pulleys 24a are provided. , 24b and 24c are configured to adjust the tension of the timing belt 23.

3 is a view showing the angular acceleration variation of the diesel engine compared to the gasoline engine in the idle (idle) conditions according to the prior art.

As shown in FIG. 3, it is difficult to develop a transmission due to an excessive angular acceleration variation of a diesel engine compared to a gasoline engine in an idle condition.

Specifically, according to the prior art, the combustion pressure increase for the high output continues, and the angular speed fluctuation which is a characteristic of the diesel engine is also increasing. This angular velocity variation adds to the difficulty in developing a transmission that receives engine power. In order to reduce the angular velocity variation, the damper 11 needs to be optimized as shown in FIG. There are limitations to the optimization work.

4A and 4B are diagrams for analyzing peak torque differences between normal oscillation and sudden oscillation according to the prior art, respectively.

4A shows the peak torque of the normal oscillation, and FIG. 4B shows the peak torque of the sudden oscillation. As a result of analyzing the difference, resonance with the transmission has a problem.

Meanwhile, the importance of fuel economy due to global warming does not need to be explained anymore. That is, the engine vibration is increased when the low temperature combustion for the EM reinforcement and the increase in the combustion pressure for high output, etc., and the damper 11 and the OAP 13 shown in FIG. There are limitations and methods for stabilizing the timing belt should be sought for fuel efficiency and noise optimization.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a method for adjusting the tension of a timing belt of an engine accessory that can optimize the tension of the timing belt for the entire driving range in terms of fuel efficiency and noise. .

In addition, another technical problem to be achieved by the present invention, by reducing the angular velocity fluctuation amount by adjusting the timing belt tension, the method of adjusting the tension of the timing belt of the engine accessories that can minimize the peak torque increase transmitted to the transmission. It is to provide.

In addition, another technical problem to be achieved by the present invention is to provide a method for adjusting the tension of the timing belt of the engine accessories that can improve the fuel economy by adjusting the optimum tension according to the state of charge, such as overcharge / fully charged. will be.

As a means for achieving the above-described technical problem, the method of adjusting the tension of the timing belt of the engine accessory according to the present invention, a) the timing belt tension is maximized when the crank is turned on by the stroke of the engine is turned on Turning on the vacuum of the variable idler so as to be loosened; b) checking whether the variable idler reaches a preset idle speed; c) checking whether the angular acceleration fluctuates when the idle speed is reached; d) optimizing the variable idler vacuum pressure in a direction of increasing belt tension when there is no variation in the angular acceleration; e) checking whether the state of charge of the battery is insufficient when there is a change in the angular acceleration; f) if the battery charge is not low, optimizing the variable idler vacuum pressure in a direction to minimize timing belt tension; And g) optimizing the timing belt tension by operating the vacuum pressure of the variable idler when the battery charge state is insufficient.

Here, step g) is characterized in that to optimize the timing belt tension in consideration of the factor value for the coolant temperature.

Here, by checking whether the start of the engine is off, and when the start is off, it may further include the step of completing the tension adjustment of the timing belt.

Here, the angular acceleration variation in step c) is calculated using an engine crank speed sensor, and the timing belt tension is optimized in response to the angular acceleration variation.

Here, the step f) is characterized in that to minimize the timing belt tension to minimize the engine mean friction effective effective pressure (Friction Mean Effective Pressure (FMEP)).

According to the present invention, it is possible to optimize the tension of the timing belt for the entire operating area in terms of fuel consumption and noise, and to improve startability by reducing the engine mean friction effective pressure (FMEP) at low temperatures. Can be.

According to the present invention, by reducing the angular velocity fluctuation amount by adjusting the timing belt tension, it is possible to minimize the peak torque transmitted to the transmission, in particular, the peak torque increase during rapid start.

According to the present invention, it is possible to eliminate or reduce the clutch oil storage tank due to the reduction of the rattle noise.

According to the present invention, since the resonance point of the automatic transmission AT or the manual transmission MT can be avoided, the durability of the transmission can be improved.

According to the present invention, the fuel economy can be improved by adjusting the optimum tension in accordance with the state of charge such as overcharge / fully charged.

According to the present invention, the cost according to the deletion of the auto tensioner can be reduced.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

As an embodiment of the present invention, by adjusting the vacuum pressure optimized for the engine environmental conditions and operating conditions using the vacuum pressure when the engine rotates to adjust the tension of the timing belt of the engine accessory to maintain the optimum belt tension in all operating conditions A method is provided.

5 is a diagram illustrating an engine accessory in accordance with an embodiment of the present invention.

Referring to FIG. 5, the accessory of the engine 100 according to the embodiment of the present invention constitutes an apparatus including an active variable idler 140 that can optimize belt vibration of a specific part according to a driving region. Here, the idler 140 is used to maintain an appropriate winding angle of each accessory in a system for driving accessories (alternator, power steering, air conditioner) with one timing belt, and is a component for improving timing durability. .

 Engine 100 according to an embodiment of the present invention, by using the vacuum pressure during the rotation of the engine to set the vacuum pressure optimized for the engine environmental conditions and operating conditions active to maintain the optimum belt tension in all operating conditions Configure a variable idler device. In this case, the idler 140 is adjusted by the idler adjusting unit, and the vacuum pressure may be selectively provided by the vacuum forming unit 170.

As software for driving the engine 100 accessory according to an embodiment of the present invention, when the ECU recognizes a cranking condition, mapping logic is used to minimize the tension of the timing belt (accessory FMEP). For example, the angular acceleration variation amount is calculated using an engine crank speed sensor, and the timing belt tension is optimized in response to the angular acceleration variation amount.

In addition, the software for driving the accessory of the engine 100 according to an embodiment of the present invention, by using the crank sensor of the engine to monitor the fluctuation of the angular speed of the engine belt tension when the required level or more in a specific region The mapping logic that maximizes is used.

In addition, as software for driving the accessory of the engine 100 according to an embodiment of the present invention, mapping logic for minimizing peak torque of the engine is used in response to the variation of the engine transmission resonance point. For example, the timing belt tension is minimized to minimize the engine mean friction effective pressure (FMEP).

In addition, as software for driving the engine 100 accessory according to an embodiment of the present invention, mapping logic is used to monitor the vehicle battery voltage to minimize belt tension during overcharge or full charge.

Additionally, the software for driving the engine 100 accessory according to an embodiment of the present invention, the logic for optimizing the belt tension for the operating region of the entire engine in consideration of environmental conditions, such as low or high temperature coolant temperature This is used.

6 is a view showing a drive system of the engine accessory according to an embodiment of the present invention.

Referring to Figure 6, the drive system of the engine accessory according to an embodiment of the present invention, the crank pulley 110, the accessory sprocket 120, the timing belt 130, idler pulleys (140a, 140b, 140c), The accessory 150 may include idle adjustment units 160a and 160b and a vacuum forming unit 170.

 Engine accessories 150 that are powered by the crank pulley 110 of the engine, for example, engine accessories 150 such as alternators, air conditioning compressors and water pumps all utilize the rotational force of the crank pulley 110. By driving, the crank pulley 110 and each shaft is mounted on the accessory sprocket 120 to transmit power through the timing belt 130.

Meanwhile, idler pulleys 140a, 140b and 140c are installed at appropriate positions between the sprockets 120 in order to enlarge the amount of contact with the timing belt 130 and prevent the belt from being separated. Such idler pulleys 140a are provided. It is configured to adjust the tension of the timing belt 130 in accordance with the movement of, 140b, 140c.

At this time, the idle adjustment unit 160 is variable, and serves to move the idler pulleys (140a, 140b, 140c). At this time, the idler pulleys 140a, 140b, 140c are moved by the vacuum pressure formed by the vacuum forming unit 170.

7 is a diagram illustrating an active variable idler according to an embodiment of the present invention.

FIG. 7 illustrates that the idler adjusting unit 160 moves the idler pulley 140 in the vertical direction in response to the vacuum pressure provided by the vacuum forming unit 170.

8 is a flowchart illustrating a method of adjusting a tension of a timing belt of an engine accessory according to an embodiment of the present invention.

Referring to FIG. 8, in the method of adjusting the tension of a timing belt of an engine accessory according to an exemplary embodiment of the present invention, first, cranking is performed by recognizing an engine operating condition, optimizing a constant value, and estimating cranking. Check whether it is On (S801), that is, if the crank is turned on by the rotation of the crankshaft by the stroke of the engine, the vacuum pressure of the active variable idler is turned on so that the timing belt tension is maximally loose. (S802).

Next, it is checked whether the active variable idler reaches the preset idle speed (S803). At this time, if the idle speed is not reached, the process returns to the above-described step S801.

Next, when the idle rotational speed is reached, it is checked whether the angular acceleration fluctuates (S804), and when there is no fluctuation in the angular acceleration, the variable idler vacuum pressure is optimized in the belt tension increasing direction (S805).

Next, if there is a change in the angular acceleration, it is checked whether the battery is in a low state (S806).

Next, when the battery state of charge is not insufficient, the variable idler vacuum pressure is optimized to minimize the timing belt tension (S807).

Next, when the state of charge of the battery is insufficient, the vacuum pressure duty map (engine speed vs. fuel amount map) of the variable idler is operated (S808).

Next, the timing belt tension is optimized in consideration of the factor value for the coolant temperature (S809).

Next, it is checked whether the startup is off (S810), and if the startup is not off, the process returns to step S803 described above, and when the startup is off, the tension adjustment of the timing belt is completed.

 The description of the present invention is for the purpose of illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

1 is a view showing the accessory of the engine according to the prior art.

2 is a view showing a drive system of the engine accessory according to the prior art.

3 is a view showing the angular acceleration variation of the diesel engine compared to the gasoline engine in the idle (idle) conditions according to the prior art.

4A and 4B are diagrams for analyzing peak torque differences between normal oscillation and sudden oscillation according to the prior art, respectively.

5 is a diagram illustrating an engine accessory in accordance with an embodiment of the present invention.

6 is a view showing a drive system of the engine accessory according to an embodiment of the present invention.

7 is a diagram illustrating an active variable idler according to an embodiment of the present invention.

8 is a flowchart illustrating a method of adjusting a tension of a timing belt of an engine accessory according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

100: engine 110: crankshaft

120: accessory sprocket 130: timing belt

140: idler 150: watch pulley

160, 160a, 160b: idler control unit 170: vacuum forming unit

Claims (5)

a) turning on the vacuum pressure of the variable idler so that the timing belt tension is maximally loosened when the cranking of the crankshaft is turned on by the stroke of the engine; b) checking whether the variable idler reaches a preset idle speed; c) checking whether the angular acceleration fluctuates when the idle speed is reached; d) optimizing the variable idler vacuum pressure in a direction of increasing belt tension when there is no change in the angular acceleration; e) checking whether the state of charge of the battery is insufficient when there is a change in the angular acceleration; f) if the battery charge is not low, optimizing the variable idler vacuum pressure in a direction to minimize timing belt tension; And g) optimizing the timing belt tension by operating the vacuum pressure of the variable idler when the battery charge is insufficient Timing belt tension adjustment method of the engine accessory including a. The method of claim 1, Step g) is the timing belt tension control method of the engine accessories, characterized in that to optimize the timing belt tension in consideration of the factor value for the coolant temperature. The method of claim 1, Checking whether the engine is turned off, and if the engine is turned off, completing the tension adjustment of the timing belt. The method of claim 1, The angular acceleration fluctuation amount of step c) is calculated using an engine crank speed sensor, and the timing belt tension adjustment method of the engine accessory, characterized in that to optimize the timing belt tension in response to the angular acceleration fluctuation amount. The method of claim 1, The step f) is the timing belt tension control method of the engine accessory, characterized in that to minimize the timing belt tension to minimize the engine mean friction mean effective pressure (FMr).

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