JP2004068735A - Control device for vehicle and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the rotating number of a motor while continuously driving an A/C compressor (an accessory) when detecting a request for starting an engine during idling stop. <P>SOLUTION: In the state of stopping the engine, of opening a clutch for connecting/disconnecting a power transmission passage between the engine and each of the A/C compressor and the motor and of driving the accessory with the motor (S1), when the request for starting the engine is detected (S2), the load of driving the A/C compressor is temporarily increased (S3) and the power torque of the motor is restricted (S4). When the rotating number of the motor is a preset value or smaller (S5), the clutch is put in engagement (S6) with the motor to start the engine. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device and a control method for a vehicle provided with an auxiliary machine, and more particularly to a technique for starting an engine by the same motor while the auxiliary machine is driven by the motor.
[0002]
[Prior art]
In recent years, in order to purify exhaust gas and improve fuel efficiency, an idle stop vehicle that automatically stops the engine when the vehicle is temporarily stopped, such as when waiting for a traffic light, and then automatically restarts the engine when a vehicle start request is detected. Is attracting attention.
[0003]
Japanese Patent Application Laid-Open No. 2001-234837 discloses that in such an idle stop vehicle, when an auxiliary machine is driven by an auxiliary machine driving motor even when the engine is stopped, and a vehicle start request is detected in this state, the auxiliary machine driving motor There is disclosed a technique for starting an engine by using an engine. That is, the accessory, the motor, and the engine are connected via the pulley and the belt, and the clutch is interposed in the power transmission path between the accessory, the motor, and the engine. When the engine is started from a state where the engine is stopped, the clutch is released, and the accessory is driven by the motor, the clutch is engaged and the engine is rotationally driven by the motor. In order to reduce the impact at the time of engaging the clutch and protect the pulley, belt and clutch, the motor speed is reduced to a predetermined speed or less before engaging the clutch. More specifically, the A / C compressor as an auxiliary machine is temporarily stopped, and the motor is regenerated by inputting a reverse phase current to the motor to reduce the rotation speed of the motor.
[0004]
[Problems to be solved by the invention]
In the technique disclosed in the related art, it is necessary to temporarily stop the A / C compressor as an auxiliary machine immediately before starting the engine, and the air conditioning performance is reduced. In addition, due to the characteristics of the motor, the motor efficiency is not so good in a low rotation speed range where the motor rotation speed is close to 0. Actually, power is not regenerated, and power is often wasted.
[0005]
The present invention has been made in view of such a problem, and when the clutch is engaged and the engine is started by the motor while the auxiliary machine is driven by the motor while the engine is stopped, wasteful power is consumed. It is a main object of the present invention to provide a novel vehicle control device and control method that can reduce the motor rotation speed toward the engine rotation speed while suppressing the consumption of power and driving the auxiliary machine.
[0006]
[Means for Solving the Problems]
In the vehicle according to the present invention, a clutch is provided in a power transmission path between the auxiliary device, the motor, and the engine. When the engine is stopped, the clutch is disengaged, and an auxiliary machine is driven by the motor, a motor rotation speed that decreases the motor rotation speed of the motor when an engine start request is detected. It has a lowering means. After the motor rotation speed or the difference between the motor rotation speed and the engine rotation speed becomes equal to or less than a predetermined value by the motor rotation speed reducing means, the clutch is engaged and the engine is started by the motor. The motor rotation speed reducing means includes a load increasing means for temporarily increasing the driving load of the accessory and a power running torque limiting means for limiting the power running torque of the motor.
[0007]
【The invention's effect】
According to the present invention, when a request to start the engine is detected in a state where the engine is stopped, the clutch is released, and the accessory is driven by the motor, the driving load of the accessory is reduced. By limiting the power running torque of the motor while increasing temporarily, it is possible to quickly reduce the motor rotation speed while continuing the driving of the auxiliary machine, engage the clutch, and start the engine. When the motor rotation speed is reduced, the motor is driven by power, so that no wasteful power is consumed by the regenerative operation in the low rotation speed region described above.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 schematically shows a configuration of a vehicle to which an embodiment of the present invention is applied. This vehicle is a hybrid vehicle that uses both an engine 1 and a motor 2 as a vehicle propulsion source. The engine 1 is a well-known gasoline engine or diesel engine that generates a driving force by burning fuel such as gasoline or light oil. The motor 2 is a three-phase AC type motor generator connected to the battery 3 via the inverter 3a, and performs a power running operation by the electric power supplied from the battery 3 during motor running or motor assist operation. Is generated and the battery 3 is charged by regenerating electric power by performing regenerative operation during vehicle deceleration or regeneration.
[0009]
FIG. 1 shows a compressor 4 of an air conditioner (A / C) as an air conditioner as one of the auxiliary devices of the vehicle. A power transmission belt 5 as a power transmission member includes a crank pulley 1b provided at a tip of a crankshaft 1a, which is a rotation shaft of the engine 1, and a motor pulley 2b provided at a tip of a rotation shaft (rotor) 2a of the motor 2. , A / C compressor 4 and a compressor pulley 4b provided at the tip of a rotating shaft 4a. A crank pulley clutch 6 is provided on a power transmission path connecting the A / C compressor 4 and the motor 2 with the engine 1, that is, a crankshaft 1a between the crank pulley 1b and the engine 1 main body. A second power transmission path connecting the engine 1 and the motor 2 to the A / C compressor 4, that is, a rotating shaft 4a between the compressor pulley 4b and the A / C compressor 4 main body has an A as a second clutch. A / C compressor clutch 7 is provided.
[0010]
A well-known torque converter 8 and an automatic transmission 9 are interposed between a crankshaft 1a of the engine 1 and a driving wheel (not shown), and a ring gear 10b that can mesh with a pinion 10a of a starter 10 is provided. ing. In this vehicle, the engine 1 is started by the starter 10 only when the engine is first started by operating an ignition key or the like, and when the engine is restarted from an idle stop or the like to be described later, the crank pulley clutch 6 is engaged and joined to connect the motor. 2, the engine 1 is restarted and motorized. The automatic transmission 9 may be a stepped automatic transmission having a plurality of planetary gear mechanisms, or may be a continuously variable transmission such as a belt type or a toroidal type.
[0011]
FIG. 2 is a system configuration diagram schematically illustrating the hybrid vehicle control device according to the present embodiment. The hybrid controller 11 controls the overall operation of the vehicle as a whole, and sends the signals to the engine controller 13, the motor controller 14, and the A / C compressor controller 15 based on detection signals from various sensors and a battery controller 12 described later. Outputs command signals and command values. The controllers 11 to 15 are well-known microcomputer systems that include a CPU, a ROM, a RAM, an input / output interface, and the like, and store and execute various arithmetic and control processes as programs.
[0012]
The engine controller 13 performs engine control such as fuel injection control and ignition timing control based on a command signal (command value) from the hybrid controller 11. The motor controller 14 performs torque control or rotation speed control of the motor 2 toward a target torque or a target rotation speed as a command value sent from the hybrid controller 11. The A / C compressor controller 15 variably controls the driving load of the A / C compressor 4 based on a command signal (command value) from the hybrid controller 11. The crank pulley clutch relay 16 controls the switching of the engagement / disengagement (ON / OFF) of the crank pulley clutch 6 based on a command signal from the hybrid controller 11, and the A / C compressor clutch relay 17 controls the hybrid controller 11 Control of switching the engagement / disengagement (ON / OFF) of the A / C compressor clutch 7 based on the command signal from the CPU.
[0013]
In the vehicle, the various types of sensors described above include an engine speed sensor 21 for detecting the speed (speed) of the engine 1, a motor speed sensor 22 for detecting the speed (speed) of the motor 2, and a brake device. M / V negative pressure sensor 23 for detecting master back (M / V) negative pressure, P / S bending angle sensor 25 for detecting power steering (P / S) bending angle, accelerator pedal corresponding to vehicle required driving force , An M / C pressure sensor 27 for detecting the master cylinder (M / C) pressure of the brake device corresponding to the amount of depression of the brake pedal, and an engine for detecting the coolant temperature of the engine 1 A water temperature sensor 28 is provided, and in addition to detection signals of these sensors, an ON / OFF signal of the A / C switch 24, a blinker signal 29, and the like are hybridized. It is input to the de-controller 11.
[0014]
The battery controller 12 described above stores the amount of charge (SOC) of the battery 3, the inputtable power and the outputable power of the battery 3 based on the voltage and current values of the battery 3 obtained from the battery voltage sensor 30 and the battery current sensor 31. And sends the SOC and the input / output possible power to the hybrid controller 11.
[0015]
FIG. 3 and FIG. 4 are a flowchart and a time chart showing a characteristic control flow of the present embodiment. In this vehicle, the vehicle speed is substantially zero, the vehicle is stopped, the SOC of the battery is sufficiently left (exceeds a predetermined value), and the brake pedal is depressed, such as at an intersection. When some of the idle stop conditions are satisfied, the fuel supply to the engine 1 is stopped, and an idle stop for stopping the engine 1 is performed.
[0016]
In S (step) 1, while the engine is stopped, more specifically, during idle stop, the crank pulley clutch 6 is released, the A / C compressor clutch 7 is engaged, and, for example, the motor 2 is stopped for a predetermined time. By controlling the rotation speed toward the target rotation speed tNm, it is determined whether or not the motor 2 is driving the A / C compressor 4 in the motor accessory driving mode.
[0017]
In S2, an engine restart request is detected. For example, when it is determined that the brake pedal is released based on the detection signal of the M / C pressure sensor 27 (or the brake switch), or when the SOC of the battery 3 sent from the battery controller 12 falls below a predetermined lower limit. For example, the engine restart request is output. T1 in FIG. 4 corresponds to the timing when the engine restart request is detected during the idle stop.
[0018]
When an engine restart request is detected during the above-described motor accessory drive mode, the processing of S3 and S4 is performed to reduce the motor rotation speed of the motor 2 (motor rotation speed reduction means). In S3, a command to increase the load torque of the A / C compressor 4 is output (load increasing means). As a result, the driving load of the A / C compressor 4 temporarily increases by a predetermined amount ΔL (FIG. 4) as compared with the required load.
[0019]
In S4, the power running torque of the motor 2 is limited (torque limiting means). That is, an increase in the power running torque of the motor 2 is prohibited. In this embodiment, in order to simplify the control and suppress the torque fluctuation of the motor 2, the upper limit value Tqmax of the power running torque of the motor 2 is set to the current value while the rotation speed control of the motor 2 toward the target rotation speed tNn is continued. The power running torque value is fixed. The motor 2 may be switched to torque control with the upper limit Tqmax as a target value.
[0020]
By the processing of S3 and S4, as shown in FIG. 4, it is possible to rapidly reduce the motor speed while continuing to drive the A / C compressor 4 as an auxiliary machine.
[0021]
In S5, it is determined whether the motor rotation speed has decreased to a predetermined value Nm0 (FIG. 4). Alternatively, it is determined whether the difference between the motor speed and the engine speed has decreased to a predetermined value, that is, whether the motor speed has sufficiently approached the engine speed. Since the engine is stopped during the idle stop, the engine speed rapidly decreases to zero due to its own friction. Therefore, the predetermined value Nm0 is set to 0 or a very low value. T2 in FIG. 4 corresponds to the timing when the motor rotation speed has decreased to the predetermined value Nm0.
[0022]
When the motor rotation speed falls to the predetermined value Nm0, the processing after S6 is executed, the crank pulley clutch 6 is engaged, and the engine is restarted by the motor 2 (engine starting means). That is, in S6, the crank pulley clutch 6 is engaged, in S7, the limitation of the motor power running torque by S4 is released, in S8, the A / C compressor clutch 7 is released (clutch releasing means), and in S9, the A / C load by S3 is released. Release the increase in torque. As a result, the power running torque of the motor 2 is effectively used as the drive torque of the engine 1 without being consumed by the A / C compressor 4, and the engine 1 can be quickly restarted, that is, motored.
[0023]
Next, for example, when the engine speed reaches a predetermined idle speed tNe, it is determined in S10 that the engine 1 has completely exploded, and if the switch of the A / C compressor 4 is on, the process proceeds from S11 to S12, and A / C In order to drive the C compressor 4 again, the A / C compressor clutch 7 is engaged. T3 in FIG. 4 corresponds to the complete explosion determination timing.
[0024]
As described above, in the present embodiment, when the restart request of the engine 1 is detected during the motor auxiliary machine drive mode in which the A / C compressor 4 is driven by the motor 2 during the idle stop (S1, S2), S6 and subsequent steps are performed. Before the crank pulley clutch 6 is engaged and the engine is restarted, the processes of S3 and S4 are performed to reduce the motor speed, so that the crank pulley clutch 6 can be smoothly engaged.
[0025]
If the regenerative operation of the motor is performed when the motor rotational speed is reduced in this way, the A / C compressor 4 cannot be driven, and the air conditioning performance is reduced. Therefore, the regenerative power cannot be obtained, and conversely, useless power is often consumed despite the regenerative operation of the motor 2.
[0026]
On the other hand, in the present embodiment, in the processing of S3 and S4, the driving load of the A / C compressor 4 is temporarily increased by ΔL, and then the powering torque of the motor 2 is limited. The motor speed can be quickly reduced while the operation of the A / C compressor 4 is continued. In addition, in the process of reducing the motor rotation speed, the motor 2 is operated not in the regenerative operation but in the power running operation, so that the power is not wastefully consumed by the regenerative operation in the low rotation region described above.
[0027]
When the engine is restarted by engaging the crank pulley clutch 6 after the motor rotation speed has decreased to the predetermined value Nm0, in steps S7 and S9, the power running torque of the motor 2 is limited and the A / C compressor 4 is driven. Since the increase in the load is canceled and the A / C compressor clutch 7 is released in S8, the power running torque of the motor 2 rapidly increases, and the power running torque is consumed by the A / C compressor 4. Because there is no, the engine can be restarted immediately. However, when the A / C compressor clutch 7 is released in this way, although the driving of the A / C compressor 4 is temporarily stopped and the air conditioning performance is reduced, the driving load of the A / C compressor 4 is increased immediately before (ΔL ), The deterioration of the air conditioning performance is effectively offset / suppressed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing one embodiment of a vehicle to which the present invention is applied.
FIG. 2 is a configuration diagram schematically showing a control device according to the embodiment.
FIG. 3 is a flowchart illustrating a control flow according to the embodiment.
FIG. 4 is a time chart from a state where an auxiliary machine is driven by a motor during idle stop to a time after an engine start.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Motor 3 ... Battery 4 ... A / C compressor 5 ... Power transmission belt 6 ... Crank pulley clutch 7 ... A / C compressor clutch (second clutch)

Claims (6)

A clutch provided in a power transmission path between the auxiliary machine and the motor and the engine;
When the engine is stopped, the clutch is disengaged, and an auxiliary machine is driven by the motor, a motor rotation speed that decreases the motor rotation speed of the motor when an engine start request is detected. Means of lowering,
After the motor rotation speed or the difference between the motor rotation speed and the engine rotation speed is reduced to a predetermined value or less by the motor rotation speed reduction unit, the clutch is engaged to start the engine by the motor. In the vehicle control device,
A control device for a vehicle, wherein the motor rotation speed reducing means includes a load increasing means for temporarily increasing a driving load of an auxiliary machine, and a power running torque limiting means for limiting a power running torque of the motor. 2. The vehicle control according to claim 1, wherein the engine starting means cancels the increase in the driving load by the load increasing means after the clutch is engaged, and cancels the limitation by the powering torque limiting means. apparatus. 3. The control device for a vehicle according to claim 1, wherein the auxiliary device is an A / C compressor. A second clutch provided on a second power transmission path connecting the motor and the engine to the auxiliary machine;
The vehicle control device according to any one of claims 1 to 3, wherein the engine starting means includes a clutch releasing means for releasing the second clutch until a complete explosion of the engine is detected. The vehicle control device according to any one of claims 1 to 4, wherein the powering torque limiting unit fixes an upper limit value of the powering torque to a current powering torque value. In a method for controlling a vehicle in which a clutch is provided in a power transmission path connecting an accessory and a motor to an engine,
When the engine is stopped, the clutch is disengaged, and a request for starting the engine is detected in a state where the accessory is driven by the motor, the driving load of the accessory is temporarily increased, and Limiting the powering torque of the motor;
When the motor speed or the difference between the motor speed and the engine speed is equal to or less than a predetermined value, a step of engaging the clutch and starting the engine by the motor.

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