JP2005048607A - Belt transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a miniaturizable belt transmission with reduced occurrence of belt slip, an extended service life of a belt, and reduced cost. <P>SOLUTION: This belt transmission is provided with a motor generator 4 for supplying starting torque to an engine 1, an endless belt 24 wound between both the pulleys 26, 23 of an electrical means and a crankshaft 22, a water pump 3 driven by the torque received from the endless belt through a pump pulley 25, a throttle opening sensor 41 detecting load information θs, and an ECU 17 rotatively driving the motor generator 4 when a load variation value Δθs according to load information exceeds a predetermined load variation determining value Δθ1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a belt transmission device that transmits power for starting an electric motor to an internal combustion engine and transmits the rotational force of the internal combustion engine to an auxiliary machine after the internal combustion engine is started.
[0002]
[Prior art]
A belt transmission device provided in an internal combustion engine wraps a belt (an endless belt) around a crank pulley attached to a crankshaft of the internal combustion engine and pulleys of auxiliary devices arranged around the internal combustion engine, thereby rotating torque. Can be communicated. In recent years, the use of an electric motor, which is one of auxiliary machines, for starting power has been studied. In this case, the power is transmitted to the internal combustion engine via the belt to start the internal combustion engine, and after the internal combustion engine is started, the rotational power of the internal combustion engine is transmitted to the other auxiliary machines via the belt.
[0003]
Other auxiliary machines such as a water pump and an air conditioner compressor are wound around the belt between the crank pulley and the pulley of the electric motor to drive them.
As an example of such a belt transmission device, a rotational force transmission system is formed by winding an endless belt between a crank pulley and a pulley of each auxiliary machine. In particular, two rotational transmission systems are included in this rotational force transmission system. Japanese Patent Laid-Open No. 2002-138849 (Patent Document 1) discloses a technique in which electric motors are distributed and thereby the belt tension can be kept low while suppressing slippage of pulleys of each rotary electric motor. 0029 ", FIG. 2 and the like.
[0004]
By the way, when the internal combustion engine is started, the pulling force from the pulley of the electric motor is applied to the crank pulley side via the endless belt, and the belt in the meantime becomes the tension side. The belt between the pulleys of the motor is on the loose side.
[0005]
For example, when a belt transmission device as shown in FIG. 8 is wound around an endless belt 100 around a crank pulley 110 of an internal combustion engine, a pulley 120 of a motor generator as an electric motor, and a pump pulley 130 of a water pump therebetween. 9 is obtained. Reference numeral 140 denotes an idler, and reference numeral 150 denotes a pulley of another engine auxiliary machine. 8 and 9, in the steady operation region A where the motor generator 120 acts as a generator and the crank pulley 110 is in steady operation, the tension p1 in the region a between the crank pulley 110 and the pump pulley 130, the pump pulley The tension p2 in the region b between 130 and the motor generator pulley 120 fluctuates relatively small. On the other hand, in the variable operation region B where the rotation speed of the crank pulley (the rotation speed of the internal combustion engine) increases rapidly, the tensions p1 and p2 in the belt regions a and b greatly increase or decrease in accordance with the change in the rotation angular velocity. . In particular, when the rotational speed of the internal combustion engine increases rapidly, it is apparent that the tension p1 varies greatly in the region a between the crank pulley 110 and the pump pulley 130, and a large drop in tension occurs intermittently.
[0006]
[Patent Document 1] JP 2002-138849 A [Problems to be Solved by the Invention]
Thus, when the internal combustion engine shifts from the steady operation region A to the variable operation region B in a state where the belt transmission is wound around the crank pulley 110 and the motor generator pulley 120 via the endless belt 100, the crank pulley 110 and The tension between the pulley 120 of the motor generator suddenly changes, and the pump pulley 130 between the two pulleys slips between the endless belt 100 and the rotational speed of the crank pulley 110 (in FIG. And a rotational difference Δn occurs in the rotational speed of the pump pulley 130 (indicated by a solid line W / P in FIG. 9). As described above, when slip occurs between the pump pulley 130 and the belt 100, the durability of the belt itself is lowered, leading to early deterioration. Moreover, if the auxiliary machine does not drive properly, for example, if the pump pulley 130 does not rotate properly, the cooling function will be reduced.
[0007]
Therefore, it is assumed that high tension is applied to the belt 100 in order to prevent slippage between the pump pulley 130 and the belt 100. In this case, the belt tension continues to be applied to the auxiliary machine even after the internal combustion engine is started, so that the life of the belt is reduced and the belt tension is applied to the pulley attached to the other auxiliary machine. In order to avoid and reduce the life of the shaft and the bearing, there is a problem in that the strength of the support structure is increased, and the size and cost of the auxiliary machine are increased.
[0008]
Furthermore, in order to reduce the occurrence of slip of the auxiliary pulley between the crank pulley and the motor pulley, it is conceivable to increase the belt width. There is a problem that it becomes large and it is difficult to secure a space for installing the belt transmission.
[0009]
Even in the case of the belt transmission device of Patent Document 1, as in the belt transmission device of FIG. 8, in the variable operation region B, there is a variation in tension in the belt in the loose side region between the crank pulley and the pulley of the motor. As a result, slip occurs in the pulley on the accessory side wound around the same part, and similarly, the function of the accessory decreases, the life of the belt decreases, and the like.
[0010]
In view of the above circumstances, there is a demand for a technique that can prevent slippage from occurring on the auxiliary pulley that is wound around the belt portion between the crank pulley and the pulley of the electric motor without increasing the belt tension. Yes.
[0011]
The present invention has been made to meet such demands, and is a belt transmission device that can reduce the occurrence of belt slip, extend the life of the belt, and reduce the size and cost. It is to provide.
[0012]
[Means for Solving the Problems]
In a belt transmission device according to a first aspect of the present invention, an electric means for supplying a starting rotational force to the internal combustion engine, an endless belt wound between pulleys of the electric means and the crankshaft of the internal combustion engine, A belt-driven auxiliary machine driven by rotational force received from an endless belt via an auxiliary pulley, load detection means for detecting load information of the internal combustion engine, and a load fluctuation value corresponding to the load information is a predetermined load fluctuation And a control means for rotating the electric means when the determination value is exceeded.
[0013]
In the belt transmission device according to claim 2 of the present invention, in the belt transmission device according to claim 1, the electric means transmits the starting power to the internal combustion engine of the idle stop vehicle using an endless belt and the internal combustion engine. It is a motor generator having both functions of a generator that generates power by receiving rotation.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an overall configuration of a belt transmission M as an embodiment of the present invention.
FIG. 1 shows a spark ignition type in-cylinder injection internal combustion engine (hereinafter simply referred to as an engine) 1 equipped with a belt transmission M, and a plurality of auxiliary water is provided around a main body 2 of the engine 1. A pump 3, a motor generator 4 as an electric means, an auto tensioner 5, a power steering 6, and the like are disposed.
[0015]
Here, the engine body 2 is formed by integrally connecting a cylinder block 7, a cylinder head 8, a head cover 9, an oil pan 11, and the like. Deploy. Above the combustion chamber 14, an injector 15 capable of directly injecting fuel into the cylinder and an ignition plug 16 for igniting the air-fuel mixture are provided.
[0016]
A constant pressure fuel is supplied to the injector 15 from a fuel supply system 16. Thereby, in the fuel injection control by the injector 15, the drive circuit (injector driver) 18 is moved along the injection amount and the injection timing which are the injection information set by the engine control unit (hereinafter simply referred to as ECU) 17. Is opened and closed, and fuel injection processing is performed for each cylinder at a predetermined time.
The ignition timing of the air-fuel mixture by the spark plug 16 is controlled by the ECU 17 via the igniter 19.
[0017]
The combustion chamber 14 draws fresh air from the intake passage r and discharges exhaust gas to the exhaust passage e. An electronic control throttle (not shown) for adjusting the amount of air taken into the combustion chamber is provided in the intake passage r. ing.
The piston 13 in the cylinder 12 is connected to a crankshaft 22 via a connecting rod 21, and one end of the crankshaft 22 is connected to a crank pulley 23.
[0018]
The crank pulley 23 is formed by an endless belt (hereinafter simply referred to as a belt) 24 so as to be able to transmit a rotational force to each auxiliary machine-side pulley described later.
The water pump 3 as an auxiliary machine is wound around the belt 24 between the crank pulley 23 and the M / G pulley 26 of the motor generator at a relatively small angle α, and receives the rotational force applied to the pump pulley 25. Driven, the cooling water in the engine body 2 is circulated to the radiator (not shown) side to cool the engine body 2.
[0019]
The motor generator 4 as the electric means functions as a generator that generates electric power by supplying rotational force from the M / G pulley 26 and as an electric motor (motor) that supplies rotational force to the belt 24 via the M / G pulley 26. It has both functions.
When the motor generator 4 functions as a generator, the generated power is sent to the battery 28 via the inverter 27. At this time, the amount of power generated by the motor generator 4 is adjusted by adjusting the amount of power sent to the battery 28 through phase control of the inverter 27. As the amount of power generated by the motor generator 4 increases, the electrical load applied to the engine 1 increases. Therefore, the electric load is made variable by adjusting the power generation amount of the motor generator 4 through the phase control of the inverter 27 by the ECU 17.
[0020]
On the other hand, when the motor generator 4 functions as an electric motor, the electric power stored in the battery 28 is supplied to the motor generator 4 via the inverter 27. The drive control of the motor generator 4 at this time is performed by phase control of the inverter 27 by the ECU 17.
[0021]
As shown in FIG. 2, the auto tensioner 5 abuts the tensioner pulley 29 on the belt 24 between the motor generator 4 and the crank pulley 23 with a relatively large winding angle β so that slip does not occur. The tensioner pulley 29 supports a movable member 32 integral with a central shaft 31 that pivotally supports the tensioner pulley 29 via a pin 34 so as to be swingable on the bracket 33 side. A compression spring 36 is disposed between the swinging end of the movable member 32 and the movable pressing piece 35 supported by the bracket 33. By adjusting the pressing force of the spring with an adjuster screw 37, the belt 24 can be adjusted. The tension applied in advance can be adjusted.
[0022]
The power steering pump 6 as an auxiliary machine abuts the power steering pulley 38 on the belt 24 between the motor generator 4 and the crank pulley 23 with a relatively large winding angle. The power steering pump 6 is driven by the rotational force applied to the power steering pulley 38 from the belt 24, and pressurizes hydraulic oil that controls a power steering actuator (not shown). As an auxiliary machine between the crank pulley 23 and the pulley 24 of the motor generator 4, in addition to the power steering pump 6, an air conditioner compressor (not shown) is provided adjacent to the power steering pump 6 and is driven simultaneously. It may be.
[0023]
The injector 15, spark plug 16, electronic control throttle (not shown), inverter 27, etc. are controlled by the ECU 17. The ECU 17 includes various detection results from the vehicle speed sensor 39 for detecting the vehicle speed vc, the throttle sensor 41 for detecting the throttle opening θs, the rotational speed sensor 42 for detecting the rotational speed Ne of the crankshaft 2, and the power generation of the motor generator 4. An amount vg, a voltage bv of the battery 28, and the like are input.
[0024]
The ECU 17 controls the switching of the combustion mode according to the operation state based on the detection result of each sensor. That is, in the low load low rotation speed region calculated based on the vehicle speed vc, the throttle opening θs, and the rotation speed Ne, compression stroke injection is performed mainly for the purpose of improving fuel efficiency, and in the high load high rotation speed region, the intake stroke is performed. By performing injection, homogeneous combustion is performed to improve output.
In this way, by switching the combustion mode according to the operating state of the engine 1, combustion control that satisfies the output characteristics required of the engine 1 can be achieved while improving fuel efficiency.
[0025]
Next, the operation of the belt transmission device M will be described. In FIG. 1, it is assumed that the engine 1 is started and is in a steady operation range, for example, a low load operation or an idle rotation range. In this steady operation area A (see FIG. 3), a constant tension is applied to the belt 24 by the auto tensioner 5, and the engine rotational torque from the crank pulley 23 is supplied via the belt 24 to the water pump 3, the motor generator 4, and the power steering 6. Each pulley is transmitted without slipping, and each auxiliary machine operates corresponding to engine rotation.
[0026]
In this steady operation region A, the throttle is at the low opening position θs1, and the motor generator 4 applies a load torque Tr1 corresponding to a predetermined electric load as a generator. Here, the tension P1 in the first slack side area a between the crank pulley 23 and the pump pulley 25 and the tension P2 in the second slack side area b between the pump pulley 25 and the M / G pulley 26 are relatively moderate. The rotational speeds v1 and v2 of the crank pulley 23 and the pump pulley 25 are also relatively gently displaced without relative displacement.
It should be noted that the characteristic of each fluctuation value in the idling operation region with respect to the steady operation region A shows almost the same characteristic although the absolute value is small.
[0027]
On the other hand, in the operation state where the accelerator is depressed from the steady operation region A, the throttle suddenly increases to the opening degree θs2, and suddenly changes to the high load region B, the motor generator 4 is switched from the power generation state to the motor operation state by an instruction from the ECU 17. The load torque Tr2 corresponding to the load is increased. As the load torque Tr2 of the motor generator 4 increases, the tension P2 on the opposite side of the water pump 3, that is, the tension side of the motor pulley 26, that is, the second slack side region b increases rapidly from the time of power generation (see symbol u in FIG. 3).
[0028]
At this time, the drive torque of the engine 1 increases due to the rapid increase of the throttle opening θs2, and the engine 1 driven as a 4-cycle machine has more torque fluctuation along the crank angle displacement, and the first loose side region There is a tendency that the tension P1 of a is relatively greatly lowered and loosely displaced. However, at this time, since the pump pulley 25 is driven by the motor pulley 26, the tension P2 of the second slack side area b is rapidly increased, so that the occurrence of slip between the belt 24 and the pump pulley 25 is prevented, and the throttle opening degree Even during the sudden increase operation of θs, the occurrence of the relative rotational difference Δn (see FIG. 9) between the rotational speeds v1 and v2 of the crank pulley 23 and the pump pulley 25 is suppressed.
[0029]
Therefore, the water pump 3 can be driven stably even when the throttle opening θs is suddenly increased, and it is not necessary to increase the belt tension to prevent slipping. There will be no deterioration in fuel consumption due to the increase.
Next, an example of belt tension control performed by the ECU 17 used in the belt transmission device M of FIG. 1 will be described along the belt tension control routine of FIG.
[0030]
Along with the engine drive, the ECU 17 controls the fuel supply of the fuel injector through the drive circuit 18 in the main routine (not shown), controls the ignition plug 16 through the igniter 19, and in the middle of that, the belt tension control routine Execute.
When step s1 of the belt tension control routine of FIG. 4 is reached, it is determined here whether or not the steady operation, that is, the low load or no-load operation (idle operation), is performed from the throttle opening θs. Then, this control is terminated, the process returns to the main routine, and the process proceeds to step s2 in the load operation region B.
[0031]
In step s2, the latest load information (throttle opening θs) is taken in, the load variation value Δθs is calculated using the time series value of the throttle opening θs, and the process proceeds to step s3.
Here, it is determined whether or not a post-load change timer TIMα, which will be described later, is “0”, and the process initially proceeds to step s4 on the Yes side. Here, it is determined whether or not the load fluctuation value Δθs exceeds a predetermined value Δθ1 (a threshold value for determining that the vehicle has left the steady operation area A is set), and in the steady operation area A, for example, the idle operation area, the process proceeds to step s6. The motor generator 4 is normally operated, this control is terminated, and the process returns to the main routine.
[0032]
On the other hand, if it is determined in step s4 that the throttle opening θs, which is a load, exceeds a predetermined value θs1, the process proceeds to step s5. Here, a predetermined value is set to the timer TIMα after the load change, that is, a time width that is considered to increase when the accelerator is depressed, and that the rotational fluctuation is settled on the high rotation side, and is equivalent to the same time width. Is set, and the process proceeds to step s6.
[0033]
When step s3 is reached again after the load change timer TIMα is turned on, the process proceeds to step s7 on the Yes side. Here, the motor generator 4 is powered by the electric power of the battery 28, and the tension P2 of the tension side of the motor pulley 26, that is, the second slack side region b is rapidly increased. Next, at step s8, "1" is subtracted from the count value of the timer TIMα after the load change, the control of this time is terminated, and the process returns to the main routine. Thus, when the count value of timer TIMα reaches zero after the load change, the process proceeds to steps s3, s4, and s6, and the power running operation of motor generator 4 is stopped.
[0034]
As described above, in the belt transmission device M of FIG. 1, even when the throttle opening θs is suddenly increased, the motor generator 4 is operated as a motor and the power pulley is driven, that is, the pump pulley 25 is wound around. The tension P2 of the second slack side area b is increased rapidly, the slippage of the pump pulley 25 with respect to the belt 24 is prevented, and the water pump 3 can be driven stably. In addition, it is not necessary to increase the belt tension with the auto tensioner 5 or the like to prevent slipping, and the fuel consumption is not deteriorated due to an increase in engine friction as in the case where the belt tension is increased.
[0035]
【Example】
Next, a case where the belt transmission device M1 is mounted on an engine 1a (see FIG. 5) of an idle stop vehicle capable of improving fuel consumption will be described as an embodiment of the present invention. The belt transmission device M1 shown in FIG. 5 differs from the device M described in FIG. 1 in the operation mode of the motor generator 4, and the connection between the crank pulley 23 and the crankshaft 22 is controlled by an electromagnetic clutch 48. Except for this point, the other configurations are almost the same, and redundant description is omitted here. The electromagnetic clutch 48 is connected to the ECU 17a via a drive circuit 49.
[0036]
This belt transmission device M1 is a main routine executed by the ECU 17a, and executes the control of the engine ignition system and the fuel supply system similar to those described above, and executes the belt tension control routine of FIG. Interrupt conditions for automatic stop control for proceeding to the automatic stop control routine shown in FIG. 6 are determined in a timely manner.
[0037]
That is, the interruption conditions for the automatic stop control here are: (a) the ignition switch 45 is on, (b) the vehicle speed Vc is “0”, and (c) the accelerator is not depressed by the output θa of the accelerator opening sensor 46. (D) The automatic stop control is entered when all the conditions that the brake is depressed by the signal Sb of the brake sensor 47 are satisfied for a predetermined time or more.
[0038]
When the ECU 17a reaches step a1 of the automatic stop control routine shown in FIG. 6, if the automatic stop control flag SFLG is “1”, the ECU 17a stops the fuel injection of the injector 15 at step a3, and if “0”, the fuel injection of the injector 15 is stopped at step a2. The spark discharge of the plug 16 is stopped and the engine 1a is stopped.
[0039]
When the engine 1a is stopped, a connection release command is output to the electromagnetic clutch 48 via the drive circuit 49 in step a3, whereby the electromagnetic clutch 48 releases the connection between the crankshaft 22 and the crank pulley 23, and step a4. Thus, the motor generator 4 is operated as a motor by power running.
As a result, the crank pulley 23 and the belt-driven auxiliary machines separated from the crankshaft 22 side can continue to exhibit the functions of the auxiliary machines when the motor generator 4 functions as an electric motor.
[0040]
In step a5, the interrupt condition for automatic stop control is determined. If the interrupt condition for automatic stop control is satisfied, the automatic stop control flag SFLG is set to "1" in step a6, and this control is terminated. Return to. If not, the automatic stop control flag SFLG is set to “0” in step a7, and the process proceeds to step a8.
In step a8, the automatic start process of FIG. 7 is executed, the control of this time is terminated, and the process returns to the main routine.
[0041]
In the automatic start process of FIG. 7, the crankshaft 22 and the pulley 23 are reconnected by the electromagnetic clutch 48 in step b1, and a driving force is applied to the crankshaft 22 by the motor generator 4 operating at this time. Is restarted. In step b2, it is determined whether or not the engine 1 is operated by itself (determination value Ne1), waits for the operation by itself, and if it is determined that the engine 1 is operated by itself based on the engine speed Ne, the process proceeds to step b3. The motor generator 4 is caused to function as a generator by the control, the control of this time is finished, and the process returns to the main routine.
By performing automatic stop control of the engine 1a, fuel efficiency is improved. Further, even during the automatic stop control of the engine 1a, the operation of the power steering pump 6 and the like is maintained by the motor generator 4.
[0042]
In the idle stop vehicle in which such automatic stop control is performed, the automatic start process is performed again from the time during the automatic stop control. In particular, when the vehicle starts suddenly, the torque fluctuation of the crank pulley becomes larger, and the first slack side area a An operation pattern in which the tension P1 is relatively lowered and loosely displaces frequently occurs. In this case, the belt tension control routine of FIG. Slip can be prevented, the water pump 3 can be driven stably, and fuel consumption does not deteriorate due to increased engine friction as in the case where the belt tension is increased by the auto tensioner 5 or the like.
[0043]
During automatic stop control, the drive torque on the crankshaft 22 side is not input to the belt transmission device side, and the motor generator 4 applies load torque Tr1 corresponding to a predetermined electric load as a generator to the belt side. For this reason, during the automatic stop control, the crank pulley 23 driven by the motor pulley 26 and the pump pulley 25 therebetween receive a relatively stable tension, and the pump pulley 25 is reliably prevented from slipping toward the belt side. .
[0044]
In the above description, the engine has been described as a spark ignition type cylinder injection internal combustion engine. However, the belt transmission device can be widely used for driving an auxiliary machine of a diesel engine and other engines.
[0045]
【The invention's effect】
According to the first aspect of the present invention, when the control means determines that the load fluctuation value of the internal combustion engine is in the operating range exceeding the load fluctuation judgment value, the electric means is rotationally driven to drive both the electric means and the crankshaft. Since tension is applied to the endless belt between the pulleys, the auxiliary pulley wound around the endless belt to which this tension is applied is prevented from slipping, and the belt-driven auxiliary machine can be driven stably. Therefore, the fuel consumption is not deteriorated due to an increase in engine friction unlike when the belt tension is increased.
[0046]
According to claim 2 of the present invention, the present invention can be easily applied to an idle stop vehicle by adopting a layout in which auxiliary pulleys are provided between both pulleys of the motor generator and the crankshaft. The effect is obtained.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a belt transmission device as an embodiment of the present invention and an engine equipped with the device.
2 is an enlarged front view of an auto tensioner used in the belt transmission device of FIG. 1. FIG.
FIG. 3 is an explanatory diagram of characteristics over time such as tensions of a first slack side region and a second slack side region of the belt used in the belt transmission device of FIG. 1 and rotation speeds of a crank pulley and a pump pulley.
4 is a flowchart of a belt tension control routine performed by an ECU used in the belt transmission device of FIG.
FIG. 5 is a schematic configuration diagram of a belt transmission device as an embodiment of the present invention.
6 is a flowchart of an automatic stop control routine performed by an ECU used in the belt transmission device of FIG.
7 is a flowchart of an automatic start control routine performed by an ECU used in the belt transmission device of FIG.
FIG. 8 is a schematic view of a conventional belt transmission.
FIG. 9 is an explanatory diagram of characteristics over time of the tensions of the first slack side region and the second slack side region of the belt used in the conventional belt transmission, the rotational speeds of the crank pulley and the pump pulley, and the like.
[Explanation of symbols]
1 Engine 3 Water pump (belt drive accessory)
4 Motor generator 17 ECU (control means)
22 Crankshaft 23 Crank pulley 24 Belt (endless belt)
25 Pump pulley (auxiliary pulley)
26 Motor pulley 41 Throttle opening sensor (load detection means)
M, M1 Belt transmission device θs Load information Δθs Load fluctuation value Δθ1 Load fluctuation judgment value

Claims (2)

Electric means for supplying a starting torque to the internal combustion engine;
An endless belt wound between pulleys of the electric means and the crankshaft of the internal combustion engine;
A belt-driven auxiliary machine driven by the rotational force received from the endless belt via an auxiliary pulley;
Load detecting means for detecting load information of the internal combustion engine;
A belt transmission device comprising: control means for rotating the electric means when a load fluctuation value corresponding to the load information exceeds a predetermined load fluctuation judgment value. The belt transmission device according to claim 1,
The rotating electric means is a motor generator having both functions of an electric motor for transmitting starting power to an internal combustion engine of an idle stop vehicle using an endless belt and a generator for generating electric power by receiving the rotation of the internal combustion engine. Belt transmission device.

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