JP2001132778A - Control device for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of overheating and deterioration due to a slip of an electromagnetic clutch and to improve its durability, in a hybrid vehicle for fastening an engine and a motor against each other via the electromagnetic clutch. SOLUTION: A hybrid vehicle comprises a drive system having a motor to generate a running drive force, an electromagnetic clutch to transmit engine rotation to the drive system, and a control circuit to control the electromagnetic clutch according to a vehicle operation state. Based on a difference between input output shaft rotation speeds during non-disengagement of a clutch, a clutch clip is detected. When an integrated value of a time in which the difference between input and output shaft rotation speeds exceeds a reference value exceeds a decision reference time, the electromagnetic clutch is disengaged and a running drive force by a motor is insured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a hybrid vehicle having an engine and a motor as power sources of the vehicle.

[0002]

2. Description of the Related Art An engine and a motor (a rotating electric machine serving both as an electric motor and a generator) as power sources for a vehicle.
There is known a hybrid vehicle having both of them and running by one or both driving forces (for example, see Japanese Patent Application Laid-Open No. H11-285107).

[0003] In such a parallel type hybrid vehicle, basically, the vehicle travels only by a motor in an operation range where the load is relatively small, and when the load increases, the engine is started to secure a required driving force. The maximum driving force is exhibited by using a motor and an engine together. Also,
When the vehicle decelerates, regenerative operation is performed in which the motor operates as a generator, and the deceleration energy is used for charging the battery.

In general, the output of an engine is transmitted to a drive system of a vehicle via an electromagnetic clutch. Conventionally, the control of the electromagnetic clutch is gradually performed in order to reduce an impact at the time of engagement. Control of transmission torque such as that described above was mainly performed, and sufficient consideration was not always given to control in consideration of the durability of the clutch.

For example, if attention is paid to durability, when a powder-type electromagnetic clutch is subjected to a half-clutch control in which the transmission torque is gradually increased or decreased under a certain high temperature state, abrasion of the magnetic powder due to the sliding operation at this time occurs. Unfavorable to promote. As a countermeasure, it is conceivable to temporarily suppress the switching of power to the engine, that is, to temporarily prohibit the engagement of the electromagnetic clutch. However, in such a case, sufficient output cannot be secured, so that drivability is impaired. I will. Alternatively, when the clutch is at a high temperature, the engagement can be rapidly performed to reduce the time required to cause a slip and thereby suppress heat generation, thereby ensuring durability. However, such control causes rapid transmission of torque. This may cause an unpleasant shock.

If the sidewalk is too high, for example, when riding on the sidewalk to enter the parking lot, the tires will not be able to get over the step and the rotation will be stopped. At this time, the accelerator pedal will be greatly depressed to get over the sidewalk. Therefore, only the engine blows up and a forced slip occurs in the electromagnetic clutch. If such a clutch slip occurs repeatedly or for a long period of time, the electromagnetic clutch will be deteriorated by heat generation, and the fastening performance will be deteriorated.

The present invention has been made in view of such a conventional problem, and has as its object to improve the durability of a hybrid vehicle by avoiding overheating of an electromagnetic clutch.

[0008]

According to a first aspect of the present invention, there is provided a driving system including a motor for generating a driving force for driving, an electromagnetic clutch for transmitting engine rotation to the driving system, and In a hybrid vehicle including an electromagnetic clutch and a control circuit that controls a motor, the control circuit detects clutch slip based on a difference in input / output shaft rotation speed when the electromagnetic clutch is not released, and performs a predetermined determination method. When it is determined that the degree of clutch slip exceeds the determination criterion based on the determination, the electromagnetic clutch is released and the driving force is secured by the motor.

According to a second aspect of the present invention, the control circuit according to the first aspect of the present invention integrates the time when the input / output shaft rotational speed difference of the electromagnetic clutch when not disengaged is greater than or equal to a reference value, and calculates the integrated value. Is provided with a process of releasing the electromagnetic clutch when the time exceeds the determination reference time as a determination method.

According to a third aspect of the present invention, the reference value for the input / output shaft rotational speed difference of the electromagnetic clutch in the second aspect of the present invention is set smaller in a higher torque range or a higher speed range.

The invention according to claim 4 is the invention according to claim 2 or 3.
The control circuit of the present invention measures a time during which the input / output shaft rotational speed difference of the electromagnetic clutch when the clutch is not released is less than a reference value, and subtracts a value obtained by multiplying the measured time by a predetermined coefficient from the integrated value. This was included in the judgment method.

[0012] The invention of claim 5 provides the above-mentioned claim 2 or 3.
The control circuit according to the present invention includes a process for measuring the time during which the electromagnetic clutch is disengaged, and subtracting from the integrated value a value obtained by multiplying the measured time by a predetermined coefficient.

[0013] The invention of claim 6 is the invention of claim 2 or 3 above.
The control circuit according to the present invention calculates the total sum of the ratio of the clutch slip occurrence time exceeding the judgment reference in each operation range to the judgment reference time set for each engine operation range, and the sum of the time ratios is a predetermined reference. The judgment method includes a process of judging that the degree of clutch slip exceeds the judgment standard when the value exceeds the value.

According to a seventh aspect of the present invention, the determination reference time according to the sixth aspect of the present invention is set smaller in a higher torque range or a higher speed range.

[0015]

According to the first and second aspects of the present invention, when a clutch slip is detected based on the input / output shaft rotation speed difference when the electromagnetic clutch is not released, the degree of the clutch slip is determined by a predetermined criterion. When it is determined that it has exceeded, the electromagnetic clutch is released, and the traveling driving force is secured by the motor. As a result, it is possible to secure the traveling function of the vehicle while preventing the performance and durability of the clutch from being reduced due to the slip of the electromagnetic clutch and the overheating caused by the slip.

As a method of determining clutch slip, the time when the rotational speed difference between the input and output shafts of the electromagnetic clutch when the clutch is not disengaged is greater than or equal to a reference value as in the invention of claim 2 is calculated. By adopting a method of releasing the electromagnetic clutch when the determination reference time is exceeded, it is possible to release the clutch at an appropriate time according to the actual load state of the clutch.

The load or heat generation at the time of clutch slip generally increases in a high torque range or a high speed range even for the same slip time.
By setting the reference value for the input / output shaft rotational speed difference of the electromagnetic clutch to be smaller in a higher torque range or a higher speed range as in the invention according to the third aspect, more accurate control can be performed for the clutch load state due to slip. It can be carried out.

On the other hand, when the frequency of occurrence of the slip is low, the heat which promotes the deterioration of the clutch performance is also reduced. A method for measuring the time that is less than the value and subtracting a value obtained by multiplying the measured time by a predetermined coefficient from the integrated value in the determination method, or a time during which the electromagnetic clutch is released as in the invention of claim 5. Is provided in the determination method by subtracting a value obtained by multiplying the measurement time by a predetermined coefficient from the integrated value, it is possible to perform more accurate control in consideration of such performance recovery of the clutch.

According to a sixth aspect of the present invention, the control circuit according to the second or third aspect of the present invention is configured such that the clutch slip exceeds a criterion in each operating range with respect to a criterion time set for each engine operating range. The sum of the ratios of the occurrence times of the times is determined, and the judgment method is provided with a process of judging that the degree of the clutch slip exceeds the judgment standard when the sum of the time ratios exceeds a predetermined reference value. By doing
Since the clutch slip can be finely determined for each operation range, the timing for forcibly releasing the clutch can be set more accurately. Also in such a determination, it is desirable to set the determination reference time to be shorter in a higher torque range or a higher speed range, as described in the invention of claim 7.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. First, FIGS. 1 and 2 show a configuration example of a parallel-type hybrid vehicle to which the present invention can be applied. In FIG. 1, the power train of this vehicle is a motor 1,
It comprises an engine 2, an electromagnetic clutch (hereinafter, simply referred to as "clutch") 3, a motor 4, a continuously variable transmission 5, a reduction gear 6, a differential gear 7, and driving wheels 8. The output shaft of the motor 1, the output shaft of the engine 2, and the input shaft of the clutch 3 are connected to each other. The motor 1 and the engine 2 are connected to each other via a reduction gear (not shown) having a predetermined rotation ratio. The output shaft of the clutch 3, the output shaft of the motor 4, and the input shaft of the continuously variable transmission 5 are connected to each other.

When the clutch 3 is engaged, the engine 2 and the motor 4
Is the propulsion source of the vehicle, and when the clutch 3 is released, only the motor 4 is the propulsion source of the vehicle. The driving force of the engine 2 or the motor 4 is controlled by a continuously variable transmission 5, a reduction gear 6, and a differential gear 7.
Is transmitted to the drive wheels 8 via the Pressure oil is supplied from the hydraulic device 9 to the continuously variable transmission 5 to clamp and lubricate the belt.

The motor 1 is mainly used for starting the engine and generating electric power, and the motor 4 is mainly used for power running and regenerative operation during deceleration of the vehicle. The motor 10 is for driving the oil pump of the hydraulic device 9. However, when the clutch 3 is engaged, the motor 1 can be used for powering and braking of the vehicle,
The motor 4 can be used for starting the engine or generating power.

The motors 1, 4, and 10 are driven by inverters 11, 12, and 13, respectively. When a DC electric motor is used for the motors 1, 4, and 10, a DC / DC converter is used instead of the inverter. The inverters 11 to 13 are connected to a high-power battery 15 via a common DC link 14, convert DC power of the high-power battery 15 into AC power, supply the AC power to the motors 1, 4, 10, and Is converted into DC power to charge the high-power battery 15. Since the inverters 11 to 13 are connected to each other via the DC link 14, the power generated by the motor during the regenerative operation can be directly supplied to the motor during the power running operation without passing through the high-power battery 15. it can.

Reference numeral 16 denotes a controller having the function of the control circuit of the present invention. The controller 16 includes a microcomputer and its peripheral parts, various actuators, etc., and transmits torque of the clutch 3, rotation speeds and output torques of the motors 1, 4, and 10. ,
The gear ratio of the continuously variable transmission 5, the fuel injection amount / injection timing of the engine 2, the ignition timing, and the like are controlled.

As shown in FIG. 2, the controller 16 includes a key switch 20, a select lever switch 21,
Accelerator pedal sensor 22, brake switch 23, vehicle speed sensor 24, battery temperature sensor 25, battery SO
A C detection device 26, an engine rotation speed sensor 27, and a throttle opening sensor 28 are connected. The select lever switch 21 turns on any one of P, N, R, and D in accordance with the set position of the select lever for switching to any of the ranges of parking P, neutral N, reverse R, and drive D.

The accelerator pedal sensor 22 detects the amount of depression of the accelerator pedal, and the brake switch 23 detects the state of depression of the brake pedal. Vehicle speed sensor 24
Detects the traveling speed of the vehicle, and the battery temperature sensor 25 detects the temperature of the high-power battery 15 (FIG. 1). The battery SOC detection device 26 detects an SOC (State Of Charge) that is a representative value of the actual capacity of the high-power battery 15. The engine rotation speed sensor 27 detects the rotation speed of the engine 2, and the throttle opening sensor 28 detects the throttle valve opening of the engine 2.

The controller 16 further includes an engine 2
, A fuel injection device 30, an ignition device 31, a valve timing adjustment device 32, and the like. The controller 16
The fuel injection device 30 is controlled to supply and stop the fuel to the engine 2 and adjust the fuel injection amount and injection timing, and the ignition device 31 is driven to control the ignition timing of the engine 2. Further, the controller 16 controls the variable valve operating device 32 to adjust the operation state of the intake and exhaust valves of the engine 2. The controller 16 includes a low-voltage auxiliary battery 3.
3 is supplied with power.

The above is an example of the basic configuration of a hybrid vehicle to which the present invention can be applied. In the present invention, the slip occurrence of the clutch 3 in such a hybrid vehicle is monitored, and the slip exceeding a predetermined criterion is performed. When the occurrence situation occurs, the clutch 3 is forcibly released to protect the clutch 3 and the traveling function of the vehicle is ensured by shifting to the traveling mode using only the motor 4. FIG. 3 shows an embodiment of the control contents of the controller 16 for this purpose.
This will be described with reference to the following drawings.

FIG. 3 is a flowchart showing an outline of the electromagnetic clutch control. This control is repeatedly executed, for example, at intervals of about 1 second as part of the overall control of the hybrid vehicle. First, an overview will be given. In this control, when a clutch slip exceeding a certain allowable limit occurs, the occurrence time is calculated, and the ratio between the slip allowable time determined for each operation range and the actual slip occurrence time is calculated. When the sum of the time ratios calculated for the respective operating ranges reaches a predetermined reference value, it is determined that the clutch 3 has reached the service limit, the clutch 3 is forcibly released, and the control is shifted to the running control using only the motor 4. .

In order to perform such control, it is first determined whether or not the clutch 3 is engaged, for example, from the state of a clutch control signal (step 001). Rotation speed difference between the input and output shafts (hereinafter referred to as “slip rotation speed”) Nslip. In this case, since the input shaft of the clutch 3 is connected to the engine 2 and the output shaft is connected to the primary shaft of the continuously variable transmission 5 via the motor 4, Nsl
ip is determined as the absolute value of the difference between the engine rotation speed Ne and the transmission primary shaft rotation speed Npri (step 002). In the configuration of FIG. 2, the engine rotation speed Ne is determined by a signal from the engine rotation sensor 27, and the primary shaft rotation speed Npri is determined by the continuously variable transmission 5.
Can be obtained from the signal from the vehicle speed sensor 24 representing the rotational speed of the output shaft (secondary shaft) and the speed ratio information.

Next, the slip rotation speed Nslip is set to a predetermined reference value tNslip (for example, tNslip = 300 rpm).
When Nslip ≧ tNslip, it is considered that a harmful slip has occurred, and the calculation processing of the damage degree Hiigai due to the occurrence of the slip is performed (steps 003, 00).
4). On the other hand, when it is determined in step 001 that the clutch is not engaged, and when Nslip <tNslip in the slip determination in step 003, this is a condition under which the performance of the clutch 3 tends to recover. A process of subtracting Hiigai is performed (step 005).

The clutch damage degree H at step 004
The calculation of igai is basically performed by calculating the ratio between the limit value tTshiyo of the time that can be continuously used under the condition of Nslip ≧ tNslip and the slip occurrence time (= operation cycle) TIME for each operation cycle,
The method uses the integrated value as the damage degree Higai. However, in this case, the limit value tTshiyo for continuous use in the above-described slip occurrence state is set for each operating region as shown in FIG. 4, and the total of the time ratios in each operating region is defined as the degree of damage. That is, in FIG. 4, four areas A, B, C, and 4 from the high speed high load side to the low speed low load side within the slip use range.
D is determined, and for each region, tTshiyo becomes smaller on the high-speed, high-load side.
16 minutes in the B area, 60 minutes in the C area, 24 minutes in the D area
It is set to 0 minutes. As a result, the clutch load, which increases as the slip occurs on the high-speed, high-load side, is reflected in the control, and the timing of the forcible clutch release described later can be more accurately determined. Assuming that the operation cycle of this control is 1 second, step 003 in FIG.
Each time it is determined that a slip has occurred in the determination in step (1), it is considered that a one-second slip has occurred.
If it is determined that the slip has occurred 0 times, it means that the slip has occurred for 1 minute.

The degree of damage Higai when such a slip occurs
For example, if a continuous slip occurs in the area A in FIG. 4 for 1 minute, in the area B for 4 minutes, and in the area C for 6 minutes, Higai = (1/1)
4) + (4/16) + (6/60) = 0.6. The value of the degree of damage Higai is the criterion tHigai (in this case, t
If (Higai = 1) is reached, it is considered that the clutch 3 has reached the use limit, the clutch 3 is forcibly released, and the mode shifts to the running mode using only the motor 4 (step 00).
6,007), and normal clutch control is performed until the reference value tHigai is not reached (step 006,00).
8).

However, when the clutch 3 is in the non-slip state, the damage Higai is reduced by the subtraction processing of the damage Higai in step 005 as described above. The processing is performed based on the result of the subtraction processing when the slip does not occur with respect to the damage degree at the time of occurrence. In this case, the damage level H
As the subtraction processing of igai, the coefficient Gensan
Is subtracted from the damage level Higai in step 004. Therefore, for example, Gensan = 1
If it is set to / 300, the damage level Higai will return to 0 by continuing the non-slip state for at least 5 minutes. Since the initial value of the damage degree Higai is 0, the subtraction processing is performed on condition that Higai> 0.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration example of a hybrid vehicle to which the present invention can be applied.

FIG. 2 is a schematic diagram showing a configuration example of a control system of the hybrid vehicle of FIG. 1;

FIG. 3 is a flowchart showing an outline of an embodiment of control by a control circuit of the present invention.

FIG. 4 is an explanatory diagram of a clutch slip determination criterion set for each operating range.

[Explanation of symbols]

 Reference Signs List 1 motor 2 engine 3 electromagnetic clutch 4 motor 5 continuously variable transmission 9 hydraulic device 10 hydraulic pressure generating motor 15 battery 16 controller 19 DC / DC converter 20 key switch 21 select lever switch 22 accelerator pedal sensor 23 brake switch 24 vehicle speed sensor 25 battery Temperature sensor 26 Battery SOC detector 27 Engine speed sensor 28 Throttle opening sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 29/00 B60K 9/00 EF Term (Reference) 3D039 AA19 AB26 AC03 3D041 AA04 AB00 AC01 AC10 AC19 AD02 AD07 AD10 AD21 AD22 AD23 AD41 AD51 AE02 AE07 AE09 AE14 3G093 AA06 AA07 BA17 CA06 CA07 CA10 CA11 DA01 DA06 DB00 DB05 DB10 DB15 DB23 EA05 EA13 EB00 EB02 FA11 FA12 5H115 PA15 PG04 PI15 PI16 PI29 PO17 PU02 Q09 PU02 Q09 RE05 RE07 RE20 SE04 SE05 SE08 SJ12 TB01 TE02 TE03 TI01 TI10 TO21 TO23 TO30

Claims (7)

[Claims] 1. A drive system including a motor for generating a driving force for driving, an electromagnetic clutch for transmitting engine rotation to the drive system, and a control circuit for controlling the electromagnetic clutch and the motor in accordance with a vehicle operating state. In the hybrid vehicle provided with the control circuit, the clutch slip is detected based on the input / output shaft rotation speed difference when the electromagnetic clutch is not released, and the degree of the clutch slip exceeds the determination criterion based on a predetermined determination method. When determined, release the electromagnetic clutch,
A control device for a hybrid vehicle in which a traveling driving force is secured by a motor. 2. The control circuit according to claim 1, wherein the control circuit integrates the time when the input / output shaft rotational speed difference of the electromagnetic clutch when not released is equal to or greater than a reference value, and activates the electromagnetic clutch when the integrated value exceeds the determination reference time. The hybrid vehicle control device according to claim 1, further comprising a release process as a determination method. 3. The hybrid vehicle control device according to claim 2, wherein the reference value for the input / output shaft rotation speed difference of the electromagnetic clutch is set smaller in a higher torque range or a higher speed range. 4. The control circuit measures a time during which the input / output shaft rotation speed difference of the electromagnetic clutch when the clutch is not released is less than a reference value, and subtracts a value obtained by multiplying the measured time by a predetermined coefficient from the integrated value. The control device for a hybrid vehicle according to claim 2, wherein the control method includes processing. 5. The method according to claim 2, wherein the control circuit measures the time during which the electromagnetic clutch is disengaged, and subtracts from the integrated value a value obtained by multiplying the measured time by a predetermined coefficient. A control device for a hybrid vehicle according to any one of the above. 6. A control circuit calculates a sum of a ratio of a clutch slip occurrence time exceeding a judgment reference in each operation range to a judgment reference time set for each engine operation range, and the sum of the time ratios is determined in advance. 4. The control device for a hybrid vehicle according to claim 2, wherein the control method includes a process of determining that the degree of clutch slip exceeds a determination reference when the reference value exceeds the reference value. 5. 7. The control device for a hybrid vehicle according to claim 6, wherein the determination reference time is set shorter in a higher torque range or a higher speed range.