JP3454167B2 - Control device for hybrid vehicle - Google Patents

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.

[0002]

2. Description of the Related Art A hybrid vehicle having both an internal combustion engine and an electric motor as a prime mover and driven by either or both driving forces is known (for example, issued by Japan Railway Company). "Automotive Engineering" VOL. 46 N
o.7 June 1997, pp. 39-52).

In such a so-called parallel type hybrid vehicle, basically, in a driving range where the load is relatively small, only the electric motor travels, and when the load increases, the internal combustion engine is started to secure a required driving force, Accordingly, the maximum driving force can be exerted by using the electric motor and the internal combustion engine together.

By the way, it is necessary to start the engine promptly when shifting from a running state using only the electric motor to an operating state in which the internal combustion engine is used. There is a problem that unpleasant vibration is likely to occur due to the effect of torque fluctuation due to pumping action and friction of the valve train. Vibration can be reduced by slowing the increase in rotation at startup, but it will take more time to obtain the required engine speed and output, making it difficult for the internal combustion engine to smoothly transition to running. Will end up.

The present invention has been made in view of these problems, and the problem is solved by controlling the torque of a rotary electric machine for starting and generating electricity connected to an internal combustion engine at the time of starting the engine and then switching to the rotation control. The purpose is to eliminate points.

The invention of claim 1 is directed to an internal combustion engine and the internal combustion engine.
It is connected to the engine so that it can drive the internal combustion engine.
In a hybrid vehicle in which a power unit including a rotating electric machine is arranged to be connectable to a drive system of the vehicle, a starting condition detecting device for detecting a condition for starting the internal combustion engine and a rotational speed of the internal combustion engine are detected. An engine rotation detection device and a control device that controls the torque and the rotational speed of the rotating electric machine are provided, and the control device starts the internal combustion engine by the rotating electric machine.
During the rotation, torque control is performed in the desired rotation range, and rotation speed control is performed in the rotation range other than the above.

According to a second aspect of the present invention, the control device is configured to perform torque control in a rotational speed range until a desired engine rotational speed is reached after starting, and thereafter perform rotational speed control.

According to a third aspect of the present invention, the torque control according to each of the above-mentioned inventions is performed by setting the basic torque value determined according to the elapsed time after starting,
It is performed based on the torque command value generated by adding the rotational vibration suppression torque that is determined according to the engine crank angle.

According to a fourth aspect of the present invention, the rotational vibration suppressing torque according to the third aspect of the invention is set to a value that cancels out the engine torque fluctuation in the vicinity of the resonance frequency of the engine mount system, and has a predetermined minimum value in the frequency range other than the above. I made it a value.

According to a fifth aspect of the invention, the value for canceling out the engine torque component of the fourth aspect of the invention is set in accordance with the operating state including the engine cooling water temperature.

According to the invention of claim 6, 0 is set as the minimum value of the rotational vibration suppressing torque in the invention of claim 4.

According to a seventh aspect of the present invention, in the control device according to the first aspect of the present invention, the rotational speed at the end of the torque control is set as the initial rotational speed at the start of the rotational speed control, and thereafter a predetermined final target rotational speed is set. It was configured to gradually change to.

[0013]

[Operation / Effect] The main cause of vibration at engine startup is the pulsating torque fluctuation due to the pumping action of the engine and the periodic frictional action of the valve train. You can Therefore, if the torque control of the rotating electric machine is performed in a predetermined rotation range during engine startup as in the inventions of claims 1 and below, the torque that cancels the pulsation in the rotation range in which the torque pulsation occurs is provided. It is possible to suppress the generation of vibration when the engine is started.
On the other hand, since the rotation speed control is performed in a region other than the torque control rotation range, when the rotation speed at the engine start increases or converges to the target rotation speed after the start, the electric motor shifts to the running state by the internal combustion engine. The drivability of can be improved.

The torque control of the rotating electric machine may be performed only in the vibration generating rotation range during the engine start, but the torque control is performed from the beginning of the start as in the second aspect of the invention, and the vibration is not generated at a predetermined rotation speed. It is also possible to shift to the rotation speed control after reaching this, which can simplify the control.

According to the third aspect of the invention, the torque control is performed based on the torque command value generated by adding the rotational vibration suppression torque determined according to the engine crank angle to the basic torque value determined according to the elapsed time after the start. Since this is performed, the torque required for starting the engine can be smoothly raised, and the vibration suppressing torque can be applied at the required portion to enable a smoother and faster engine start.

According to the invention of claim 4, the rotational vibration suppressing torque of the invention of claim 3 is set to a value that cancels out the engine torque fluctuation in the vicinity of the resonance frequency of the engine mount system.
A predetermined minimum value, for example, in a frequency range other than the above, for example, 6
Since it is set to zero as in the invention described above, it is possible to reduce the amount of control torque in a region other than the rotation range that cancels out engine torque fluctuations, and minimize the drive power consumption of the rotating electric machine.

According to the invention of claim 5, the value for canceling out the engine torque component of the invention of claim 4 is set in accordance with the operating state including the engine cooling water temperature. When the engine is started while the vehicle is in operation, the so-called hot start is usually performed after the warm-up is completed, so the vibration characteristics at the start are stable, but the vibration caused by internal friction of the engine is affected by temperature and atmospheric pressure. . Therefore, by setting the torque offset amount according to these operating states as in the present invention, it is possible to ensure the vibration reduction effect even at the time of starting under different operating conditions such as cold starting.

According to the invention of claim 7, the control device of the invention of claim 1 sets the rotational speed at the end of the torque control as the initial rotational speed at the start of the rotational speed control, and thereafter sets a predetermined final target. Since it is configured to gradually change to the rotation speed,
It is possible to smoothly reduce the difference from the target rotation speed at the time of shifting from the torque control to the rotation speed control, and avoid the occurrence of a shock due to a sudden change in the rotation speed.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION 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 hybrid vehicle to which the present invention can be applied. Each of these is a parallel type hybrid vehicle that travels by using the power of either or both of an engine (internal combustion engine) and an electric motor according to the traveling conditions.

In FIG. 1, a thick solid line indicates a mechanical force transmission path, and a thick broken line indicates a power line. Also, a thin solid line indicates a control line, and a double line indicates a hydraulic system. The power train of this vehicle includes a motor 1 (the rotating electric machine of the present invention), an engine 2, a clutch 3, a motor 4, a continuously variable transmission 5, a speed reducer 6, a differential gear 7, and drive 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, and 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. ing.

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 disengaged, only the motor 4 is the propulsion source of the vehicle. The driving force of the engine 2 or the motor 4 is the continuously variable transmission 5, the speed reducer 6 and the differential device 7.
Is transmitted to the drive wheels 8 via. Pressure oil is supplied from the hydraulic device 9 to the continuously variable transmission 5, and the belt is clamped and lubricated. An oil pump (not shown) of the hydraulic device 9 is driven by the motor 10.

The motor 1 is mainly used for engine starting and power generation, and the motor 4 is mainly used for propulsion (power running) and braking of the vehicle. The motor 10 is for driving the oil pump of the hydraulic device 9. Further, when the clutch 3 is engaged, the motor 1 can be used for propulsion and braking of the vehicle, and the motor 4 can be used for engine starting and power generation. The clutch 3 is a powder clutch and can adjust the transmission torque. The continuously variable transmission 5 is a continuously variable transmission such as a belt type or toroidal type, and can continuously adjust the gear ratio.

The motors 1, 4, 10 are driven by inverters 11, 12, 13 respectively. When DC electric motors are used as the motors 1, 4 and 10, a DC / DC converter is used instead of the inverter. The inverters 11 to 13 are connected to the main battery 15 via the common DC link 14, and the main battery 15
DC charging power of the motor is converted into AC power and the motors 1, 4, 1
0 is supplied to the main battery 15 as well as the AC power generated by the motors 1 and 4 is converted into DC power. Since the inverters 11 to 13 are connected to each other via the DC link 14, the electric 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 main battery 15. it can. As the main battery 15, various batteries such as a lithium-ion battery, a nickel-hydrogen battery, and a lead battery, and an electric double-layer capacitor so-called power capacitor are applied.

Reference numeral 16 denotes a controller having the function of the control device of the present invention, which comprises a microcomputer and its peripheral parts, various actuators, etc., and transmits torque of the clutch 3 and the rotational speeds and output torques of the motors 1, 4 and 10. Controls 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.

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 speed sensor (engine speed detection device of the present invention) 27, and a throttle opening sensor 28 are connected. The key switch 20 is closed when the key of the vehicle is set to the 0N position or the START position (hereinafter, switch closing is ON or 0N, open is OFF or OF.
Call it F). The select lever switch 21 is a switch for selecting one of P, N, R, and D depending on the setting position of a select lever (not shown) that switches to any range of parking P, neutral N, reverse R, and drive D. Turns on.

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 (switch-on at this time). The vehicle speed sensor 24 detects the traveling speed of the vehicle,
The battery temperature sensor 25 detects the temperature of the main battery 15. Further, the battery SOC detection device 26 has a SOC (State Of State) that is a representative value of the actual capacity of the main battery 15.
Charge) is detected. Further, 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.

A fuel injection device 30, an ignition device 31, a variable valve operating device 32, etc. of the engine 2 are also connected to the controller 16. The controller 16 uses the fuel injection device 3
0 to control the supply and stop of fuel to the engine 2 and to adjust the fuel injection amount / injection timing, and to set the ignition device 31.
To control the ignition timing of the engine 2. Further, the controller 16 controls the variable valve operating device 32 to adjust the operating states of the intake / exhaust valves of the engine 2. The controller 16 is supplied with power from a low-voltage auxiliary battery 33.

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, vibration reduction at the time of starting is reduced by optimally controlling the motor 1 at the time of engine starting in such a hybrid vehicle. It is intended to be realized. An embodiment of the functional configuration and control contents of the controller 16 for this purpose will be described below with reference to the drawings starting from FIG.

FIG. 3 is a functional block diagram showing the structural concept of the portion of the controller 16 relating to the start-up control of the motor 1, and FIG. 4 is a schematic diagram showing the control characteristics of this motor control. As shown in FIG. 4, in this control, torque control is performed at the beginning of starting, and after reaching a certain rotation speed, rotation speed control is performed.

In FIG. 3, reference numeral a designates a start timing detecting section for detecting the engine start time. This issues a start command when it is necessary to start the engine in the process of controlling the traveling of the hybrid vehicle, and therefore the start is started based on this command. b is a torque command calculation unit that calculates a torque command value for the motor 1 from the beginning of the engine 2 (see FIG. 1) or the time when the motor 1 reaches a predetermined rotation speed from the start, and c is the predetermined rotation speed. This is a rotation speed command calculation unit that calculates a rotation speed command value for the motor 1 after the torque control calculation unit b reaches a value and the torque control by the torque command calculation unit b ends. Reference numeral d is a rotation speed detection device that detects the rotation speed of the motor 1, and e is a command switching unit that switches between a torque command value and a rotation speed command value based on the detected rotation speed. Since the motor 1 and the engine 2 are connected so as to interlock at a specific rotation speed ratio, the engine rotation sensor shown in FIG. 2 can be used as the rotation speed detection device d. Reference numeral f denotes a motor control unit that supplies a drive current to the motor 1, and drives the motor 1 based on the torque command value or the rotation speed command value selected by the command switching unit e.

Next, the details of the motor control will be described with reference to FIG.
A description will be given along the flow chart shown in FIG. In this control, first, it is detected whether or not the engine needs to be started. If it is not the starting condition, the process is terminated, and if it is the starting condition, the engine speed Ne is detected (steps 501 to 503). Next, the engine speed Ne is the number of revolutions No. for switching to the revolution speed control.
It is determined whether or not the above (step 504). Since Ne <No at the beginning of the engine start, the flow advances to the torque control flow from step 505.

In the torque control, the basic output torque Ta, the rotational vibration suppression torque Tb, and the compensation coefficient Kt for this Tb.
(However, Kt ≦ 1) is calculated (step 50)
5-507). The basic output torque Ta is used to secure the basic torque required for the engine starting cranking, and is given as a characteristic that increases as time elapses from the start of the engine as shown in FIG. 6, for example. The rotational vibration suppression torque Tb is for canceling out the pulsating torque fluctuation appearing on the engine main shaft due to the pumping action of the engine and the frictional resistance of the valve train as described above, and is necessary for this cancellation. The torque characteristic is determined in advance by experiments and given as the characteristic shown in FIG. The compensation coefficient Kt is set as illustrated in FIG. 8. This is because the rotation vibration suppressing torque Tb is applied only in the vicinity of a specific rotation range where vibrations occur, for example, the resonance frequency range of the engine mount. This is for minimizing the driving power. The final torque command value St is obtained by superimposing a value obtained by multiplying the rotational vibration suppression torque Tb by the compensation coefficient Kt on the basic output torque Ta, and outputs the command value St to drive the motor 1. Repeat (steps 508 and 509). As a result, it is possible to effectively reduce the unpleasant vibration that occurs during the engine starting process.

On the other hand, when the engine speed exceeds the switching speed No in the process of the torque control, the flow of the speed control from step 510 onward is switched based on the determination in step 504. As the switching rotation speed No, a value near the lower limit value of the rotation speed range in which no unpleasant vibration is generated during the engine starting is basically set. In this rotation speed control, first, in order to switch the control of the motor 1 to the rotation speed control, a target rotation speed Nt is calculated according to the operating state at that time, and a rotation speed command value Sn corresponding to this Nt is calculated (step 510, 511). Next, the engine speed Ne is compared with the target speed Nt, and while Ne is larger than Nt, a value obtained by subtracting a predetermined gradual decrease dS from the command value Sn is set as a command value Sn and output ( Step 512, 51
3,514). When Ne becomes Nt, step 5
The Sn calculated in 11 is output as it is. By repeating this control, the motor 1 is controlled in rotation speed such that the rotation speed is gradually reduced toward the target value Nt by an amount corresponding to the gradual decrease dS, with the engine rotation speed at the end of the torque control as an initial value. . The rotational speed control is started immediately after the rotational range in which the torque control is required is exceeded, whereby the increase in the rotational speed at the time of engine start can be accelerated, and the running of the engine can be smoothly shifted.

9 to 11 show the experimental results by the above control. This shows the relationship between the engine speed (vertical acceleration) and the engine speed when the engine throttle is fully opened and the engine speed is changed from 0 to 700 rpm depending on the presence or absence of viscosity compensation and pulsation correction. Viscosity compensation means torque correction mainly considering frictional resistance of the valve train, and pulsation correction mainly means torque correction considering pumping action. FIG. 9 shows the effect of the embodiment of the present invention in which each correction is applied, and FIG. 10 shows the effect when only the pulsation correction is applied.
Shows the case where only viscosity compensation is applied. From comparison between FIG. 9 and FIG. 10, it can be seen that the viscosity compensation improves the rotation speed followability immediately after the start with respect to the rotation command value. Further, from the comparison between FIG. 9 and FIG. 11, it can be seen that rotational pulsation and vibration are sufficiently reduced by the pulsation compensation.

[Brief description of drawings]

[Figure 1]

FIG. 2 is a schematic configuration diagram showing a configuration example of a hybrid vehicle to which the present invention can be applied.

FIG. 3 is a functional block diagram showing a configuration concept of an embodiment of a control device of the present invention.

FIG. 4 is a characteristic diagram showing an outline of motor control characteristics according to the embodiment.

FIG. 5 is a flowchart showing the contents of control operation according to the above embodiment.

FIG. 6 is a characteristic diagram showing a control characteristic of basic output torque in the above embodiment.

FIG. 7 is a characteristic diagram showing a control characteristic of rotational vibration suppression torque.

FIG. 8 is a characteristic diagram of a compensation coefficient for the rotational vibration suppression torque.

FIG. 9

FIG. 11 is a vibration characteristic diagram for explaining the effect of the embodiment.

[Explanation of symbols]

1 motor (rotary electric machine) 2 engine (internal combustion engine) 3 clutch 4 motor 5 continuously variable transmission 9 Hydraulic system 10 Motor for hydraulic pressure generation 15 battery 16 controller 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 speed sensor (engine speed detector) 28 Throttle opening sensor 35 Water temperature sensor 41 Pressure sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI F02D 29/06 F02D 29/06 D (56) References JP-A-9-191504 (JP, A) JP-A-9-47092 ( JP, A) JP 61-155635 (JP, A) JP 10-205365 (JP, A) JP 8-98322 (JP, A) JP 8-98321 (JP, A) JP Japanese Unexamined Patent Publication No. 8-98320 (JP, A) Japanese Unexamined Patent Publication No. 4-297330 (JP, A) Japanese Unexamined Patent Publication No. 7-102955 (JP, A) Special Table 2001-513978 (JP, A) International Publication 98/039560 (WO, A1) ) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60L 11/14 B60K 6/04 F02D 29/06 F02D 29/02

Claims (7)

(57) [Claims] 1. An internal combustion engine and the internal combustion engine can be driven mutually.
And a rotating electric machine for starting the internal combustion engine.
In the hybrid vehicle power unit is arranged to be connectable to a drive system of the vehicle was example, the start condition detection device for detecting a starting condition that requires an internal combustion engine, and the engine speed detecting device for detecting the rotational speed of the internal combustion engine, the rotation A control device for controlling the torque and the rotation speed of the electric machine, wherein the control device starts the internal combustion engine by the rotary electric machine.
A hybrid vehicle control device configured to perform torque control in a desired rotation range and to perform rotation speed control in a rotation range other than the above when operating. 2. The control device is configured to perform torque control in a rotational speed range until a desired engine rotational speed is reached after starting, and thereafter perform rotational speed control. Control device for hybrid vehicle. 3. The torque control is performed based on a torque command value generated by adding a rotational vibration suppression torque determined according to an engine crank angle to a basic torque value determined according to an elapsed time after starting. The control device for a hybrid vehicle according to claim 1 or 2. 4. The rotational vibration suppressing torque is set to a value that cancels out the engine torque fluctuation in the vicinity of the resonance frequency of the engine mount system, and is set to a predetermined minimum value in the frequency range other than the above. A control device for the hybrid vehicle described. 5. The control device for a hybrid vehicle according to claim 4, wherein the value for canceling out the engine torque is set according to an operating state including the engine cooling water temperature. 6. The control device for a hybrid vehicle according to claim 4, wherein 0 is set as the minimum value. 7. The control device is configured to set a rotation speed at the end of torque control as an initial rotation speed at the start of rotation speed control, and thereafter gradually change to a predetermined final target rotation speed. The control device for a hybrid vehicle according to claim 1, wherein: