JP2001112109A - Controller of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the responsiveness and durability via powder clutch, which the engine and motor of a hybrid vehicle are coupled with each other, when the engine is coupled with the motor while it is in operation. SOLUTION: A hybrid vehicle has a powder clutch, which transmits the rotation of an engine to a drive system which has a travel driving motor. When an engine is stopped and powder clutch is released and the vehicle is in a travel state only by the motor, a minute current smaller than a coupling current is supplied to the powder clutch and powder is suitably distributed over a clutch operation plane beforehand, so as to improve the clutch responsiveness at the time of coupling.

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 A powder clutch is known as a driving force transmitting element for a vehicle. The powder clutch generally comprises an outer drum Do connected to the input shaft and an inner drum D connected to the output shaft, as shown in FIG.
powder (magnetic powder) having magnetism on the operating surface S between the i and i
P is enclosed. An excitation coil (not shown) for adsorbing the powder P is provided on the outer drum Do. By energizing this coil, the powder P is adsorbed on the operating surface S between the inner and outer drums to generate a fastening force. To transmit the driving force. (Refer to, for example, Japanese Patent Application Laid-Open No. 10-213158 for a known document of the powder clutch.) In a clutch disengaged state in which the coil is not energized, when the input shaft is stopped or rotating at a low speed, the powder P is moved on the operating surface by gravity. Although it accumulates below, when the rotation of the input shaft rises to some extent, it is widely distributed along the operation surface on the outer drum Do side due to centrifugal force as shown in the figure. For this reason, when the clutch is engaged after the engine speed has risen, such as at the time of starting, the engaging operation is performed relatively responsively, and quick starting performance can be obtained.

On the other hand, in a parallel hybrid vehicle having a powder clutch provided between a traveling motor and an engine, the clutch engagement operation may be performed under the condition that the rotation of the input shaft is stopped or at a low speed. Below, there arises a problem that the response of the clutch engagement is deteriorated, the acceleration response is deteriorated, and an unpleasant shock is generated.
Generally, in such a hybrid vehicle, in order to save fuel consumption, the vehicle runs only with the power of the running motor provided in the drive system in a relatively low load or low-speed driving state (in this manner, the vehicle runs only with the power of the motor). This is called powering),
During this time, the clutch is released and the engine is stopped. When a large driving force is required from this powering state for acceleration or the like, the engine is started, the clutch is connected, and the engine power is added.

[0004] In the powder clutch which is open at the time of power running, the output shaft and the inner drum Di rotate at a relatively high speed together with the motor, but centrifugal force does not act on the outer powder P depending on the rotation of the inner drum Di. Therefore, the powder P is only agitated by the inner drum Di, and is not distributed along the operation surface S (see FIG. 6). Therefore, even if the coil is energized to apply the exciting force to transmit the engine power, it takes time until the powder P is attracted along the operating surface, and therefore, compared to the operation as the starting clutch. As a result, the engagement response is reduced.

[0005] Further, in the inner turning state in which only the inner drum Di is rotating with the clutch released, the powder P accumulates below the clutch and is agitated, generating a local frictional force. It also causes a decrease in the durability of the powder clutch, for example, the wear of the surface S is promoted. (Publications of hybrid vehicles include, for example, “Automotive Engineering” Vol. 46 No. 7, June 1997, 39-5
See page 2. The present invention has been made in view of such conventional problems, and has as its object to improve the engagement responsiveness of a powder clutch from an inner turning state in a hybrid vehicle, or to improve the durability thereof. .

[0006]

According to a first aspect of the present invention, there is provided a drive system including a motor for generating a driving force for driving, a powder clutch for transmitting engine rotation to the drive system, and And a control circuit for controlling the powder clutch, wherein the control circuit is configured to apply a predetermined weak current to the powder clutch when the engine is stopped and the powder clutch is released and the vehicle is in a running state using only the motor. It was configured to supply.

According to a second aspect of the present invention, the control circuit according to the first aspect of the present invention is configured to supply a weak current only in a predetermined operation range of an operation range in which the powder clutch is released.

According to a third aspect of the present invention, the operation range for supplying the weak current according to the second aspect of the invention is set near a powder clutch engagement region determined according to an operation state.

According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the value of the weak current supplied to the powder clutch is determined such that the transmission torque of the powder clutch becomes smaller than a predetermined value. It was taken.

According to a fifth aspect of the present invention, in the first or second aspect, the value of the weak current supplied to the powder clutch is determined so that the response time until engagement is smaller than a predetermined value. It was taken.

According to a sixth aspect of the present invention, in the first or second aspect of the present invention, the value of the weak current supplied to the powder clutch is set to be smaller than a value determined in response time until engagement according to an operating state. It was decided to be.

[0012]

According to the first and second aspects of the present invention, when it is necessary to fasten the engine and the drive system, a weak current is supplied to the powder clutch in advance so that the powder moves along the clutch operation surface. Since the distribution is substantially evenly distributed (see FIG. 7), the powder clutch quickly enters the engaged state with the supply of the engaging current. Therefore, the engine can be smoothly connected to the drive system without causing a shock under a favorable engagement response.

[0013] Further, since the powder is dispersed along the clutch operation surface under the supply of the weak current as described above, local friction does not occur due to the powder, and thus the durability of the powder clutch is improved.

The supply of the weak current may be performed only in a specific operating range, for example, in an operating range excluding a range in which the engagement response of the powder clutch does not need to be so high as described above. In particular, when the reduction in durability due to the bias of the powder is not so problematic, it is possible to save power by limiting the operation range for supplying such a weak current.

In order to limit the operation range for supplying the weak current, a method may be adopted in which the weak current is supplied only near the operating point where the powder clutch is engaged, as described in the third aspect of the present invention. The operating point at which the powder clutch is engaged can be predicted in advance based on the operating state of the hybrid vehicle, and by supplying a weak current only in the vicinity of such an engaging operating point, in order to enhance the engagement response. Power consumption can be minimized.

The value of the weak current supplied to the powder clutch can be determined based on the transmission torque of the powder clutch, as described in the fourth aspect of the present invention. Since the powder clutch has the characteristic that the fastening force changes according to the supply current value, even if a weak current exceeds a certain limit, the input shaft side stopped between the output shaft side and the output shaft side driven by the motor Dragging may occur, resulting in friction loss. Such a problem can be avoided by setting the weak current value so that the transmission torque becomes almost zero.

Further, the value of the weak current supplied to the powder clutch is based on the time of the engagement response when the engagement current is supplied from the state where the weak current is supplied, as described in the fifth aspect of the invention. Can be determined. The coupling response required to connect the drive system rotating by the motor to the engine can be experimentally investigated in advance, and the value of the weak current must be determined as long as the required response characteristics are satisfied. Thus, waste of power can be prevented.

Further, the required response characteristics may vary depending on the driving conditions such as vehicle speed and load. In such a case, the required response characteristics according to the driving conditions are satisfied. By variably controlling the weak current value in such a manner, more efficient clutch control can be achieved.

[0019]

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,
The engine 2 includes a powder clutch (hereinafter simply referred to as a “clutch”) 3, a motor 4, a continuously variable transmission 5, a reduction gear 6, a differential 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 and various actuators. ,
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 a basic configuration of a hybrid vehicle to which the present invention can be applied. In the present invention, by appropriately controlling the current when the powder clutch 3 is opened in such a hybrid vehicle, It is intended to improve the fastening response or durability.
An embodiment of the control contents of the controller 16 for this purpose will be described below with reference to FIGS.

FIG. 3 is a flowchart showing an outline of the powder clutch control. This control is repeatedly executed at a cycle of, for example, about 10 ms as part of comprehensive control of the hybrid vehicle. In this control, it is first determined whether or not a clutch ON (engagement) instruction is given in the course of vehicle control, and when there is an instruction, the rated current is immediately supplied to the powder clutch 3 to perform the engagement to perform one control loop. Is completed (steps 001 and 002). If there is no instruction to turn on the clutch, it is next determined whether or not the engine 2 is rotating based on a signal from the engine speed sensor 27 (step 003). Signal from sensor 24 or inverter 1
It is determined whether or not the motor 4 is rotating based on the supply current from the motor 2 (step 005).

When the engine 2 is stopped and the motor 4
Is rotating, the operation is started from the in-clutch turning state when the operating state requires engine power thereafter, so that a predetermined weak current is supplied to the powder clutch 3 (step 006). FIG. 4 shows a setting example of the current value supplied at this time. FIG. 4 shows the relationship between the supply current value to the powder clutch 3 and the response time from release to engagement, and the value of the weak current is determined as long as the required target response time is satisfied. This is, for example, assuming that the rated current value supplied at the time of fastening is 4.4 A, the weak current value is about 0.2 A.

When a weak current is not supplied to the powder clutch 3 in a power running state in which only the motor 4 is rotating,
As shown in FIG. 6, since the powder P is substantially agitated by the inner drum Di and remains substantially below the inside of the clutch, the response time to the supply of the fastening current becomes longer.
In contrast, by supplying a weak current, FIG.
Since the powder P is distributed on the operating surface S by the exciting force as shown in FIG.
The engagement operation is completed promptly in response to the supply of the engagement current in 002), so that it is possible to avoid the occurrence of a shock due to the deterioration of the clutch response. In addition, by dispersing the powder P along the operation surface S in this manner, it is possible to reduce the risk of causing the powder P to locally wear and improve the durability.

On the other hand, when it is determined in step 003 that the engine 2 is rotating, or when it is determined in step 005 that the motor 4 is stopped, the current is supplied to the powder clutch 3 in either case. One control loop is ended (step 004). During the rotation of the engine, the powder P is distributed on the operation surface S due to the rotation of the outer drum Do as shown in FIG. When the motor 4 is stopped, the vehicle is stopped, so there is no need to immediately engage the clutch. Therefore, in either case, no clutch current is supplied.
This saves power.

[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 a characteristic diagram showing a relationship between a current value supplied to a powder clutch and a response time.

FIG. 5 is an explanatory diagram showing a state of a powder clutch when functioning as a starting element.

FIG. 6 is an explanatory diagram showing an inner turning state of the powder clutch.

FIG. 7 is an explanatory diagram showing a state when a weak current is supplied to a powder clutch.

[Explanation of symbols]

 Outer drum of Do powder clutch Di Inner drum of Powder clutch P Powder (magnetic powder) S Operating surface of powder clutch 1 Motor 2 Engine 3 Powder clutch 4 Motor 5 Continuously variable transmission 9 Hydraulic device 10 Motor for generating hydraulic pressure 15 Battery 16 Controller Reference Signs List 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 detection device 27 Engine rotation speed sensor 28 Throttle opening sensor

Claims (6)

[Claims] 1. A drive system including a motor for generating a driving force for driving, a powder clutch for transmitting engine rotation to the drive system, and a control circuit for controlling the powder clutch according to a vehicle operating state. In the hybrid vehicle, the control circuit, when the engine is stopped and the powder clutch is released and the vehicle is in a running state using only the motor,
A control device for a hybrid vehicle configured to supply a weak current smaller than an engagement current to a powder clutch. 2. The control device for a hybrid vehicle according to claim 1, wherein the control circuit is configured to supply the weak current only in a predetermined operation range of an operation range in which the powder clutch is released. 3. The control device for a hybrid vehicle according to claim 2, wherein the operation range in which the weak current is supplied is set near a powder clutch engagement range determined according to an operation state. 4. The control device for a hybrid vehicle according to claim 1, wherein the value of the weak current supplied to the powder clutch is determined so that the transmission torque of the powder clutch is smaller than a predetermined value. . 5. The hybrid vehicle control device according to claim 1, wherein the value of the weak current supplied to the powder clutch is determined such that a response time until engagement is smaller than a predetermined value. . 6. The method according to claim 1, wherein the value of the weak current supplied to the powder clutch is determined such that a response time until engagement is smaller than a value determined according to an operating state.
3. The control device for a hybrid vehicle according to claim 1.