JP3925498B2 - Control device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem that fully opening a throttle at deceleration for improving regenerative efficiency would cause air quantity and output to be temporarily larger than their requirements upon completion of regeneration, thus causing a torque difference. <P>SOLUTION: This hybrid vehicle is structured so as to transmit the driving force of either or both of an internal combustion engine and a dynamo-electric machine, and equipped with a throttle drive for controlling the throttle opening of the internal combustion engine corresponding to its running state, and a regenerative controller for regeneratively operating the dynamo-electric machine at deceleration at which an engine brake is applied. The throttle drive is controlled so as to always obtain a minimum required throttle opening corresponding to engine speed at regenerative operation. <P>COPYRIGHT: (C)2004,JPO&amp;NCIPI

Description

  The present invention relates to a control device for a hybrid vehicle.

  There is known a hybrid vehicle that has both an internal combustion engine and a rotating electrical machine (an electric motor that also functions as a generator) as a prime mover, and is driven by one or both driving forces.

In such a so-called parallel type hybrid vehicle, the vehicle is basically driven only by an electric motor in an operation region where the load is relatively small, and when the load increases, the internal combustion engine is started to ensure a required driving force, and if necessary, The combined use of an electric motor and an internal combustion engine allows the maximum driving force to be exhibited.
Railway Japan Co., Ltd. “Automotive Engineering” VOL.46 No.7 June 1997, pages 39-52

  By the way, at the time of deceleration when the driver returns the accelerator pedal, a regenerative operation for charging the battery is performed by driving the electric motor with the reverse driving force from the driving system to generate electric power. This is intended to increase energy efficiency while securing a deceleration force by using a load during power generation by an electric motor in addition to an engine braking action due to internal friction of the internal combustion engine. In order to increase the efficiency of this regenerative operation, it is better to reduce the engine brake action as much as possible and increase the power generation load accordingly. From this point of view, there is one that stops the fuel supply to the internal combustion engine during regeneration and maximizes the throttle opening to reduce friction loss due to pump loss.

  However, when the throttle is fully opened in this way, when the regenerative operation is completed and the fuel supply to the internal combustion engine is resumed, the fuel supply resumes from a state where the intake air amount is large. As a result, the output becomes excessive with respect to the output to be generated, and a torque step is generated, which may cause discomfort to the passenger. In addition, the fact that the amount of air does not decrease immediately due to the delay in the operation of the actuator that controls the throttle opening degree also contributes to the generation of a torque step.

  The present invention has been made paying attention to such a problem, and an object thereof is to suppress the generation of a torque step at the end of regeneration.

  The present invention is configured to transmit a driving force of one or both of an internal combustion engine and a rotating electric machine to a drive system of a vehicle, and controls a throttle opening degree of the internal combustion engine according to an operating state; In a hybrid vehicle including a regenerative control device that stops the fuel supply to the internal combustion engine connected to the drive system during deceleration and regenerates the rotating electrical machine, the throttle drive device is configured so that the intake pipe negative pressure is reduced during the regenerative operation. The throttle opening is controlled by feeding back the intake pipe negative pressure so as to be a predetermined target intake pipe negative pressure.

  In the present invention, when a predetermined regeneration condition is established, the vehicle drive system and the internal combustion engine are generally connected, and the driver decelerates by operating the accelerator pedal to return the accelerator pedal from an operating state where the engine speed or vehicle speed is equal to or higher than a predetermined value. Is started, the fuel supply to the internal combustion engine is stopped and the regenerative operation by the power generation of the rotating electrical machine is started. The throttle opening during the regenerative operation is not constant, and is controlled so that a predetermined target intake pipe negative pressure is obtained by feeding back the intake pipe negative pressure. Such throttle control is basically based on a throttle driving device including, for example, an accelerator sensor, an actuator for driving the throttle, and a control device for controlling the actuator.

  In the present invention, the throttle opening is controlled so that the target intake pipe negative pressure can be obtained regardless of the engine speed. Therefore, the regeneration efficiency is increased based on the intake pipe negative pressure that strongly correlates with the occurrence of pump loss. However, it can be accurately controlled by a preferable throttle opening that does not cause a torque step.

  As described above, in order to increase the regeneration efficiency, it is desirable to open the throttle and reduce the intake pipe negative pressure on the downstream side in order to reduce the pump loss of the internal combustion engine. However, as shown in FIG. 5, the intake pipe negative pressure changes according to the engine rotational speed Ne, and develops at higher speeds even at the same throttle opening. If the intake pipe negative pressure is kept constant, the throttle opening decreases as the speed decreases.

  Therefore, basically by controlling the throttle to be closed and adjusted as the engine rotates at a low speed, the throttle opening is minimized and the intake pipe negative pressure that does not cause a pump loss, for example, −100 mmHg or less, is maintained to achieve high regeneration efficiency. It can be secured. In addition, by maintaining the throttle opening to a minimum in this manner, for example, the amount of engine intake air when the regenerative operation ends due to the driver's braking operation or the like is suppressed, and the delay of the actuator that controls the throttle opening is controlled. Can be minimized to prevent the occurrence of a torque step when resuming fuel supply.

  Note that depending on the engine, such as a high compression ratio engine or an engine having a rotation range where the intake charge efficiency increases, the pump loss may be reduced by generating a certain amount of intake pipe negative pressure in a specific rotation range. That is, the above-described control for reducing the throttle opening as the engine speed decreases is generally effective, but the characteristic of the optimum throttle opening with respect to the actual engine speed can be different depending on the characteristics of the individual engines.

Actions / Effects Actions / Effects Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, FIGS. 1 to 4 show configuration examples of a hybrid vehicle to which the present invention can be applied. These are parallel type hybrid vehicles that travel using the power of either one or both of an engine (internal combustion engine) and an electric motor (rotary electric machine) according to traveling conditions.

  In FIG. 1, a thick solid line indicates a transmission path of mechanical force, and a thick broken line indicates a power line. A thin solid line indicates a control line, and a double line indicates a hydraulic system. The power train of the vehicle includes a motor 1, an engine 2, a clutch 3, a motor 4, a continuously variable transmission 5, a reduction gear 6, a differential device 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 serve as a vehicle propulsion source, and when the clutch 3 is released, only the motor 4 serves as a vehicle propulsion source. The driving force of the engine 2 or the motor 4 is transmitted to the drive wheels 8 via the continuously variable transmission 5, the speed reducer 6, and the differential device 7. The continuously variable transmission 5 is supplied with pressure oil from the hydraulic device 9, and the belt is clamped and lubricated. An oil pump (not shown) of the hydraulic device 9 is driven by a motor 10.

  The motor 1 is mainly used for engine start and power generation, and the motor 4 is mainly used for vehicle propulsion (also referred to as power running) and braking. The motor 10 is for driving an oil pump of the hydraulic device 9. In addition, when the clutch 3 is engaged, the motor 1 can be used for vehicle propulsion and braking, 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 a toroidal type, and the gear ratio can be adjusted steplessly.

  The motors 1, 4 and 10 are driven by inverters 11, 12 and 13, respectively. In the case where 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 the main battery 15 via a common DC link 14. The inverter 11 to 13 converts the DC charging power of the main battery 15 into AC power and supplies it to the motors 1, 4, 10. 4 to convert the AC generated power into DC power and charge the main battery 15. In addition, 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 going through the main battery 15. it can. As the main battery 15, various batteries such as a lithium ion battery, a nickel / hydrogen battery, a lead battery, and an electric double layer capacitor, a so-called power capacitor, are applied.

  The controller 16 has a function as a regenerative control device of the present invention, and includes a microcomputer, its peripheral components, various actuators, etc., and the transmission torque of the clutch 3, the rotational speed and output torque of the motors 1, 4 and 10, and nothing. It also has functions for controlling the gear ratio of the stepped 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, an accelerator pedal sensor 22, a brake switch 23, a vehicle speed sensor 24, a battery temperature sensor 25, a battery SOC detection device 26, and an engine speed sensor 27. A throttle opening sensor 28 is connected. The key switch 20 is closed when the vehicle key is set to the 0N position or the START position (hereinafter, the switch closing is referred to as ON or 0N, and the opening is referred to as OFF or OFF). The select lever switch 21 is one of P, N, R, and D switches according to the set position of a select lever (not shown) that switches to any of the ranges of parking P, neutral N, reverse R, and drive D. Turns on.

  The accelerator pedal sensor 22 detects the amount of operation of the accelerator pedal, and the brake switch 23 detects the depression state (switch-on at this time) of the brake pedal. The vehicle speed sensor 24 detects the traveling speed of the vehicle, and the battery temperature sensor 25 detects the temperature of the main battery 15. Further, the battery SOC detection device 26 detects SOC (State Of Charge) which is a representative value of the actual capacity of the main battery 15. Further, the engine speed sensor 27 detects the speed of the engine 2, and the throttle opening sensor 28 detects the throttle valve opening of the engine 2.

  The controller 16 is connected to a fuel injection device 30, an ignition device 31, a variable valve operating device 32, and the like of the engine 2. The controller 16 controls the fuel injection device 30 to supply and stop the fuel to the engine 2 and adjust the fuel injection amount / injection timing, and drives the ignition device 31 to control the ignition timing of the engine 2. The controller 16 controls the variable valve device 32 to adjust the operating state of the intake / exhaust valves of the engine 2 and also functions as a control device for a throttle drive device to be described later. The controller 16 is supplied with power from a low-voltage auxiliary battery 33.

  FIG. 3 or FIG. 4 is a diagram illustrating an arrangement example of the power train. The motor 1 and the engine 2 on the input side of the clutch 3 may be arranged upstream of the engine 2 as shown in FIG. 3, or the motor 1 may be arranged downstream of the engine 2 as shown in FIG. You may arrange. In the arrangement example shown in FIG. 3, the output shaft of the engine 2 is directly connected to the input shaft of the clutch 3 to form one shaft, and the output shaft of the engine 2 is connected to the output shaft of the motor 1 by a belt or a gear. Further, in the arrangement example shown in FIG. 4, the output shaft of the engine 2 passes through the rotor of the motor 1 and is directly connected to the input shaft of the clutch 3, and the input side of the clutch 3 is constituted by one shaft.

  On the other hand, the motor 4 and the continuously variable transmission 5 on the output side of the clutch 3 may be arranged upstream of the continuously variable transmission 5 as shown in FIG. 3, or as shown in FIG. The motor 4 may be disposed downstream of the continuously variable transmission 5. In the arrangement example shown in FIG. 3, the output shaft of the clutch 3 passes through the rotor of the motor 4 and is directly connected to the manpower shaft of the continuously variable transmission 5, and the output side of the clutch 3 is configured as a single shaft. Further, in the arrangement example shown in FIG. 4, the output shaft of the clutch 3 passes through the input shaft of the continuously variable transmission 5 and is directly connected to the output shaft of the motor 4, and the output side of the clutch 3 is configured with one shaft. In either case, the motor 4 is connected to the input shaft of the continuously variable transmission 5.

  The arrangement of the power train is not limited to the arrangement examples shown in FIGS. 3 and 4. The engine 2 and the motor 1 are connected to the input shaft of the clutch 3, and the motor 4 and the continuously variable transmission 5 are connected to the output shaft of the clutch 3. As long as the propulsion mechanism connects the input shaft and transmits power from the output shaft of the continuously variable transmission 5 to the drive wheels 8 via the speed reducer 6 and the differential device 7, each device can be arranged in any arrangement.

  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, the optimum throttle control is performed at the time of regenerative operation of such a hybrid vehicle to generate a torque step at the end of regeneration. The main purpose is to avoid it. Next, a schematic configuration example of the throttle driving device and a control operation example of the controller 16 for this purpose will be described with reference to the drawings.

  FIG. 6 shows a configuration example of a throttle drive device that electronically controls the throttle opening of the engine 2 described above. In the figure, reference numerals 22 and 27 respectively denote an accelerator pedal sensor and an engine speed sensor for detecting the operation amount of the accelerator pedal described above. An air flow meter 34 detects the amount of intake air per unit time to the engine 2. A water temperature sensor 35 detects the engine cooling water temperature. 36 is a fuel injection valve, and 37 is a spark plug. A throttle valve 39 is interposed in the intake passage 38 of the engine 2, and an actuator 40 such as a step motor for driving the throttle valve 39 is provided. The actuator 40 basically opens the accelerator opening so that the throttle opening corresponding to the output required for the engine is obtained in response to the output request determined according to the operation amount of the accelerator pedal based on the signal from the accelerator sensor 22. Feedback control is performed by the controller 16 while detecting the actual opening by the sensor 28 (see FIG. 2). However, during regenerative operation, correction control is performed so that a predetermined throttle opening is obtained based on a signal from the engine speed sensor 27. In the figure, reference numeral 41 denotes a pressure sensor for detecting the intake pipe pressure downstream of the throttle valve 39, and feedback control is performed so that the intake pipe negative pressure becomes a predetermined value to control the opening degree of the throttle valve 39. Used when controlling.

  FIG. 7 shows details of the throttle control. In this control, first, the net target torque to be generated by the engine 2 by adding / subtracting the offset amount TEOFS such as the driving force generated by the motor 4 and the load torque of the air conditioner to the target torque determined from the operation amount of the accelerator pedal. TTI is calculated (see part A in FIG. 7). KTEH is a learning correction amount for the offset amount. Next, based on the target torque TTI and the engine speed NE at that time, the required intake air volumetric flow rate TGADNV is obtained by table search, and further, the required opening area TQHOTE of the intake pipe is determined by table search (same as above). B to C). Since this TQHOTE is a unit amount, it is multiplied by the engine speed and the cylinder volume to obtain an opening area TTAETD corresponding to the total intake air amount of the engine, and this is converted into a throttle valve opening TGTVO by table search (same as above). See D to E). The TGTVO is a target throttle opening degree in a normal operation state where the accelerator pedal is depressed, and the opening changing speed is limited by a changing speed limiter for stable operation (see F The required throttle opening is obtained by feedback control of the actuator 40 (see FIG. 6) while detecting the actual opening.

  On the other hand, at the time of deceleration at which fuel cut is performed, the throttle opening value TGTVFC at the time of fuel cut obtained by table search from the engine speed NE is output as the target throttle opening TGTVO (see the G section). As described above, the throttle opening at this time is set to a necessary limit that can prevent the occurrence of a torque step while increasing the regeneration efficiency. TVBCV is a lower limit value of the throttle opening given by the table in accordance with the engine speed NE so that the intake pipe negative pressure does not become excessive (see part H).

  Next, an embodiment of the throttle opening control at the time of fuel cut described above will be described. FIG. 8 is a control characteristic diagram showing the first embodiment, and corresponds to the table of G section in FIG. In this embodiment, as shown in the figure, basically, the throttle opening is decreased as the engine speed is decreased, thereby reducing the throttle opening to the minimum necessary level and improving the regeneration efficiency, while increasing the regeneration efficiency. In addition to this, the target regeneration amount is detected to correct the target throttle opening for each engine speed. As described above, when the regenerative amount is small, the deceleration action due to the power generation load of the motor 1 or 4 is reduced, so that the throttle is closed by that amount to ensure the deceleration force due to the engine braking effect. . The target regeneration amount is calculated from a signal from battery SOC detection device 26 (FIG. 2). In an engine equipped with a variable valve device that variably controls the operating angle and lift amount of the intake / exhaust valve according to the engine speed, the pump loss changes according to the operating state of the variable valve device. It is desirable to correct the target throttle opening so that the required regeneration amount or deceleration can be obtained in consideration of the above.

  FIG. 9 is a flowchart showing a control operation during deceleration according to the second embodiment. This calculates the magnitude of the torque step based on the engine speed at the end of regeneration and the target throttle opening, and avoids the occurrence of a torque step by compensating for the torque corresponding to this step by driving the rotary electricity. It is what I did.

  In this control, first, after reading the target throttle opening degree TGTVO, it is determined whether or not the fuel cut state continues. If the fuel cut is in progress, it is determined from the table as shown in FIG. 10 based on the vehicle speed at that time. The target regeneration amount is determined so as to obtain the regenerative torque, and the regenerative operation is performed (steps 901 to 904).

  When the accelerator pedal is depressed during the deceleration process, the fuel supply is resumed and the regenerative operation ends. At this time, if it is immediately after the fuel cut, the engine speed NE and the target throttle opening TGTVO at that time are read in preparation for calculating the compensation torque for eliminating the torque step (steps 905 to 906). Next, the target throttle opening read in step 901 is set as the previous value TGTVOp, and a change amount dTVO of the throttle opening is obtained from the difference between the previous value TGTVOp and the current value TGTVO. By searching such a table, the compensation torque Tmta is set, and the motor is driven so that this compensation torque is output (steps 907 to 908, 912). In this way, the torque corresponding to the torque step at the time of resumption of fuel supply is compensated for by the motor, thereby avoiding the generation of the torque step.

  In the subsequent control loop, it is determined in step 905 that it is not immediately after the resumption of fuel supply. This is a process for gradually changing the actual torque to an output corresponding to the target throttle opening by gradually reducing the compensation torque. For this purpose, first, the rotational speed NE is read, a correction time constant equivalent value Kfc (where Kfc <1) is retrieved from the table shown in FIG. 12 based on the NE, and the previous value Tmtap of the compensation torque is multiplied by Kfc. The motor is driven with the new compensation torque Tmta as the new compensation torque (steps 909 to 912). Thereby, since the motor torque corresponding to the torque step compensation is gradually reduced, the torque input to the drive system can be smoothly changed to ensure good drivability.

FIG. 1 is a first schematic configuration diagram showing a configuration example of a hybrid vehicle to which the present invention is applicable. The 2nd schematic block diagram which shows the structural example of the hybrid vehicle which can apply this invention. The 3rd schematic block diagram which shows the structural example of the hybrid vehicle which can apply this invention. The 4th schematic block diagram which shows the structural example of the hybrid vehicle which can apply this invention. The characteristic view which shows the relationship between throttle opening, intake pipe negative pressure, and engine speed Ne. The schematic block diagram which shows the structural example of a throttle drive device. The control conceptual diagram which shows the outline of the control action of a throttle drive device. The characteristic diagram which shows the control characteristic of the throttle opening by 1st Embodiment of the control action of this invention. The flowchart which shows 2nd Embodiment of the control action of this invention. The characteristic diagram of the table for calculating | requiring the regenerative torque from a vehicle speed in control of the said 2nd Embodiment. The characteristic line figure of the table for calculating | requiring compensation torque from an engine speed and throttle opening in control of the said 2nd Embodiment. The characteristic line figure of the table for calculating | requiring the correction time constant equivalent value Kfc from an engine speed in control of the said 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,4 Electric motor 2 Engine 3 Clutch 5 Continuously variable transmission 9 Hydraulic device 10 Oil pressure generation motor 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 (capacity detection device)
27 Engine speed sensor 28 Throttle opening sensor 35 Water temperature sensor 39 Throttle valve 40 Actuator 41 Pressure sensor

Claims (2)

A throttle drive device configured to transmit the driving force of one or both of the internal combustion engine and the rotating electric machine to a vehicle drive system, and controls the throttle opening of the internal combustion engine according to the operating state, and the drive system during deceleration In a hybrid vehicle comprising a regenerative control device for stopping the fuel supply to the internal combustion engine coupled to the regenerative operation of the rotary electric machine,
A hybrid vehicle configured to control the throttle opening by feeding back the intake pipe negative pressure so that the intake pipe negative pressure becomes a predetermined target intake pipe negative pressure during the regeneration operation. Control device.   The throttle drive device includes an accelerator sensor that detects an operation amount of an accelerator pedal, an actuator that drives a throttle valve, and a control device that drives the actuator based on an operation amount signal from the accelerator sensor. Hybrid vehicle control device.

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