JP2008068704A - Vehicular drive source control apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive source control apparatus for a hybrid vehicle that can achieve high responsive start and stable vehicle behavior. <P>SOLUTION: The drive source control apparatus for a hybrid vehicle comprises a detection means for detecting a wheel slip during torque assist, and a torque reduction means for reducing the assist torque of a motor when a wheel slip is detected. The torque is assisted by a motor at a command torque depending on accelerator position, and when a wheel slip is detected, the assist torque is reduced immediately. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle drive source control device, and more particularly to a vehicle drive source control device including an engine and a motor as drive sources.

  In a so-called parallel type hybrid vehicle, there is known a technique for reducing the engine noise and improving the fuel consumption during running by performing torque assist by a motor at the time of starting or accelerating by utilizing the difference in characteristics of the drive source.

  For example, Japanese Patent Laid-Open No. 2005-325804 discloses that a motor is used for a certain period of time from the start in order to prevent deterioration in fuel consumption due to excessive depression of the accelerator pedal by the driver when starting from an idling stop state during eco-run (economy & ecology running). It has been proposed to implement torque assist.

JP 2005-325804 A

  In the method of Patent Document 1, in order to ensure high response performance, the torque instruction amount for the motor is calculated according to the accelerator opening (for example, paragraph 0040 of Patent Document 1, etc.). Therefore, particularly when the driver accelerator pedal is strongly depressed, as shown in FIG. 8, it is considered that the torque becomes excessive as the engine torque rises and the tire slips.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to optimize an assist torque instruction value when performing torque assist by a motor at the time of start, and to provide a vehicle with stable response and stable start. An object of the present invention is to provide a vehicle drive source control device capable of satisfying both of these behaviors.

  According to a first aspect of the present invention, there is provided a vehicle drive source control device that includes an engine and a motor as drive sources, and that performs torque assist by the motor at an instruction torque according to an accelerator opening degree when starting. And detecting means for detecting slip of the wheel during the torque assist, and torque reducing means for reducing the assist torque of the motor when the slip of the wheel is detected compared to when the slip is not detected. A drive source control device for a vehicle is provided. Therefore, this vehicle drive source control device executes assist torque reduction control immediately after wheel slip detection even during a predetermined torque assist period.

  According to the present invention, it is possible to optimize the assist torque instruction value when performing torque assist by the motor at the time of starting, and to achieve both high responsiveness and stable behavior of the vehicle.

[First Embodiment]
Next, the best mode for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a hybrid vehicle to which the present invention can be applied. With reference to FIG. 1, an engine (hereinafter also referred to as “EG”) 11 typified by an internal combustion engine, and a motor generator (hereinafter also referred to as “MG”) 12 driven by electricity stored in a battery 19. Two types of prime movers are arranged in parallel to drive the wheels.

  The output of the engine 11 is transmitted to the transmission 13, and then transmitted to the axle shafts 15, 15 ′ and the drive wheels 16, 16 ′ via a differential device (differential) 14 that is an output unit to drive the vehicle. To do. Similarly, the output of the MG 12 can drive the vehicle via a differential device (differential) 14.

  Further, the hybrid vehicle of FIG. 1 includes an HV-ECU (Hybrid Electronic Control Unit) 21 that controls the entire vehicle, an MG-ECU and an inverter 22 that commands the MG 12 to drive or regenerate, and a stop and combustion state of the engine 11 An EG-ECU 23 for controlling the transmission, a clutch actuator 17 incorporated in the transmission 13, an AMT-ECU 24 for controlling the transmission actuator 18 to perform an optimum shift, and a battery ECU 25 for managing the state of charge of the battery 19.

  The HV-ECU (torque reduction means) 21 operates as a vehicle drive source control device, and controls and manages the MG-ECU, the inverter 22, the EG-ECU 23, and the battery ECU 25 in response to the driving intention of the driver. Further, the EG-ECU 23 generates the best combustion state in cooperation with the AMT-ECU 24, and performs fuel control when the engine is started by the starter 20. In addition, an indicator 26 that displays the speed of the vehicle is provided in the driver's seat.

  FIG. 2 is a skeleton diagram showing a schematic configuration (fourth speed state) of the drive mechanism of the hybrid vehicle. First, the structure on the transmission 13 side will be described. A flywheel 32 is fixed to the end of the output shaft 31 of the engine 11. A clutch element 33 is attached to the flywheel 32, and is engaged and disengaged by the clutch actuator 17. It is possible. The driven member of the clutch is integrally attached to the input shaft 34 of the transmission 13 in the rotational direction by a spline or the like. On the input shaft 34, drive gears of 1st 35, Rev 36, 2nd 37 are integrally formed in order from the clutch side, and further, drive gears of 3rd 38, 4th 39, 5th 40, 6th 41 are rotatably mounted. Further, the output shaft 42 of the transmission 13 is provided in parallel with the input shaft 34, and the 1st43, 2nd44 driven gears are rotatable at positions where the gears mesh with the respective gears, and the 3rd45, 4th46, 5th47, 6th48 driven The gear is mounted integrally. A drive gear 49 that meshes with a ring gear (final gear) 70 provided in the case of the differential (differential) 14 is integrally attached to the clutch-side end of the output shaft 42 of the transmission 13. Yes. Furthermore, a shaft 50 parallel to the input shaft 34 of the transmission 13 is provided on the transmission 13 side, and a Rev idler gear 51 is rotatably mounted. The Rev idler gear 51 is also movable in the axial direction and does not mesh with the Rev drive gear 36 at the clutch side position (thick solid line), but can mesh with the Rev drive gear 36 at the position on the 6th drive gear 41 side (thin line). It has become.

  Hub members 52, 53, and 54 that are fixedly rotated with the respective shafts are provided between the driving gears and the driven gears of the input shaft 34 and the output shaft 42 of the transmission 13. Each hub member has an engaging means such as a spline on the outer periphery, and further meshes with sleeve members 55, 56, 57 provided on the outer periphery, and the sleeve is moved in the axial direction (left and right in the figure) by the speed change actuator 18. The left gear and the right gear mesh with the spline and transmit power, and the neutral state does not mesh with any gear. In FIG. 2, the sleeve member 56 moves to the left and is in the fourth speed state. Further, the sleeve member 55 between the first shaft 43 and the second shaft 44 of the output shaft 42 is provided with a gear 58 at a portion extending to the outer peripheral portion. And is in two states, a neutral state and a Rev drive state.

  As described above, the driving force of the engine 11 is engaged with the clutch by the clutch actuator 17, and is transmitted to the first drive gear 49 at the end of the output shaft 42 according to the speed ratio selected by the speed change actuator 18.

  On the other hand, the driving force output by the MG 12 is transmitted to a driving gear 61 provided integrally at the end of the MG output shaft 60. An intermediate reduction shaft 62 disposed in parallel with the MG output shaft 60 meshes with a driven gear 63 that meshes with a driving gear 61 and a ring gear (final gear) 70 that is provided in a case of a differential (differential) 14. And a driving force of the MG 12 is transmitted to the second driving gear at a predetermined reduction ratio.

  With the above configuration, the output of the engine 11 and the MG 12 is transmitted to the ring gear (final gear) 70 by the HV-ECU (Hybrid Vehicle Electronic Unit) 21 and via the differential device (differential) 14 as necessary. The axle shafts 15 and 15 'and the drive wheels 16 and 16' are driven after absorbing the difference in rotational speed.

  The MG 12 has both functions of a power running state in which electric power is received and converted into driving force, and a regenerative state in which driving force is converted into electric power. The magnetic force generated in the stator member 66 by the three-phase electric power is By passing a large amount of current at a position optimal for returning through the iron portion, control is performed so that efficient conversion including generation of driving force and control of the rotation direction can be performed.

  On the opposite side of the output shaft 60 of the MG 12, a resolver (detection means) 65 is attached as a rotation detection sensor. The resolver 65 detects a relative angle between the stator member 66 around which the coil of the MG 12 is wound and the rotor member 67 that rotates integrally with the MG output shaft 60, and can be used as a resolver signal. For example, the resolver signal can be used as the vehicle speed by converting the numerical value depending on the number of poles of the MG 12 and the gear ratio on the MG 12 side. Further, the slip amount of the wheel can be estimated by measuring the change in the resolver signal per unit time.

  Subsequently, control of the drive source in the hybrid vehicle having the above configuration will be described in detail with reference to the drawings. FIG. 3 is a flowchart showing a process performed every predetermined time when the HV-ECU 21 starts.

  Referring to FIG. 3, first, the HV-ECU 21 determines a torque such as whether or not a predetermined assist permission condition such that a state of charge (SOC) of the battery 19 is equal to or higher than a predetermined value and the MG 12 is equal to or lower than a predetermined temperature. After confirming the assist conditions, the MG torque corresponding to the accelerator opening is calculated (step S010).

  Subsequently, the HV-ECU 21 checks whether or not the current vehicle speed of the vehicle is less than a predetermined threshold A (step S020). Here, when the current vehicle speed of the vehicle is equal to or higher than the threshold value A, the MG torque is gradually decreased (introgression) to smoothly switch to the engine torque instead of the MG torque calculated from the accelerator opening. Processing is executed (step S070; see FIG. 6).

  If the current vehicle speed of the vehicle is less than the threshold value A in step S020, the command torque to the MG 12 is determined by the MG torque calculated from the accelerator opening, and the current vehicle speed of the vehicle becomes greater than or equal to the threshold value A in step S020. If so, the instruction torque to the MG 12 is determined by the MG torque after the MG torque is gradually reduced (changed) in step S070.

  Subsequently, the HV-ECU 21 executes a slip detection process (step S040). For this slip detection, for example, a known method using the difference between the front and rear wheel speeds, the vehicle speed (or the vehicle speed calculated from the resolver signal from the resolver 65 of the MG 12) and the acceleration of the rotating member of the transmission can be used. The result is held in, for example, a slip determination flag.

  As a result of the slip detection process, when it is determined that no slip has occurred, the HV-ECU 21 issues a command to the MG-ECU with the MG torque determined in step S030 (NO in step S050). .

  On the other hand, if it is determined that slip has occurred, the HV-ECU 21 performs MG torque reduction processing for reducing the current MG torque instruction value by a predetermined width (step S060). Finally, the MG-ECU is instructed with the MG torque reduced in step S060 (see FIG. 6).

  As described above, according to the present embodiment, the occurrence of slip during torque assist by the motor can be reliably captured and reflected in the MG torque instruction value. For this reason, it is possible to achieve both a highly responsive start according to the driver's intention (accelerator operation) and the stability of the behavior of the vehicle at the start.

[Second Embodiment]
Subsequently, a second embodiment of the present invention to which a function of changing the MG torque reduction range according to the road surface condition is added will be described. Since the present embodiment can be realized with a configuration substantially similar to that of the first embodiment described above, the difference will be mainly described.

  FIG. 4 is an example of a table showing the correspondence between the slip amount of the wheel and the estimated road surface state. FIG. 5 is a map showing the relationship between the slip amount and the correction coefficient (0 to 1.0) applied at the time of slip detection.

  The table of FIG. 4 can estimate the road surface condition from the amount of change in rotation per unit time of the resolver signal from the resolver 65 attached to the output shaft of the MG 12. For example, if the rotation change amount is level 1 which is the smallest range, it is estimated that the slip amount is “small” and the road surface state is “dry”. Further, for example, if the rotation change amount is level 10 in the largest range, it is estimated that the slip amount is “large” and the road surface state is “freezing”.

  Here, referring to the map of FIG. 5, the correction coefficient (0 to 1.0) to be multiplied by the basic correction amount serving as a base is set so that the significant decrease correction is performed as the rotation change amount (slip amount) increases. Is set. In addition, the correction coefficient does not decrease in proportion to the rotation change amount (slip amount), but when the rotation change amount (slip amount) exceeds the two threshold values Th1 and Th2, the decrease rate increases. Is set.

  In the present embodiment, when slip is detected in step S050 of FIG. 3, MG torque reduction processing corresponding to the slip amount is performed in the MG torque reduction processing of next step S060.

  FIG. 6 is a diagram showing the operation of the vehicle according to the present invention when slip is detected but the slip amount is small (road surface state = “dry”). Referring to FIG. 6, simultaneously with the occurrence of slip appearing on the wheel axis torque line, a slip determination flag is set, and MG torque reduction processing using a correction coefficient (correction width: small) obtained using the map of FIG. Has been started. Thereafter, when the wheel recovers the grip and the vehicle speed becomes equal to or higher than the threshold value A, the MG torque gradually decreasing process is started, the MG torque gradually decreases, and finally the torque assist is finished.

  FIG. 7 is a diagram showing the operation of the vehicle according to the present invention when a slip is detected and the slip amount is large (road surface condition = “freezing”). Referring to FIG. 7, the slip determination flag is set simultaneously with the occurrence of the slip appearing on the wheel shaft torque line, and the MG torque reduction process is started as in FIG. 6. However, the applied correction coefficient is small (correction width: large), and the waveform is such that the MG torque drops significantly compared to FIG. In addition, by applying a large correction range, there is a section where the MG torque command value becomes a negative value. This causes a torque absorption operation (braking operation) with the MG 12 as a load, and slips. This is for prompt suppression. After the wheel has recovered grip by the torque absorbing operation (braking operation), the same as the case where the slip amount is small, but since the MG torque has already dropped, the MG torque gradual reduction process becomes unnecessary.

  According to the present embodiment that operates as described above, in addition to the effects of the first embodiment, fine assist torque control according to the estimated road surface condition is possible. For example, in a situation where the vehicle is on ice and the driving wheels are idling, not only the torque of the MG 12 is reduced, but also the torque absorbing operation is performed, so that the grip can be recovered more quickly.

  As mentioned above, although the suitable form for implementing this invention was demonstrated, the technical scope of this invention is not limited to description of each embodiment mentioned above, According to the specification of the vehicle etc. which are applied. Various modifications can be made.

  For example, in the above-described embodiment, an example of a hybrid vehicle in which the driving force output by the MG is transmitted to the differential device (differential) 14 has been described, but the engine and the motor are in a parallel relationship. Therefore, it can also be applied to start control of other vehicles that drive the vehicle.

1 is a block diagram showing a configuration of a hybrid vehicle to which the present invention can be applied. 1 is a skeleton diagram illustrating a schematic configuration (fourth speed state) of a vehicle drive mechanism according to an embodiment of the present invention. It is a flowchart showing the process performed for every predetermined time at the time of start in the drive source control measure (HV-ECU) of the vehicle which concerns on one Embodiment of this invention. It is an example of the table showing the correspondence of the slip amount of the wheel used by the 2nd Embodiment of this invention, and the estimated road surface state. It is the map showing the relationship between the slip amount used in the 2nd Embodiment of this invention, and the correction coefficient applied at the time of slip detection. It is a figure for demonstrating the operation | movement (road surface state = "dry") of the 2nd Embodiment of this invention. It is a figure for demonstrating the operation | movement (road surface state = "freezing") of the 2nd Embodiment of this invention. It is a figure for analyzing and explaining operation (excess torque state) of an embodiment of the conventional hybrid vehicle.

Explanation of symbols

11 Engine (EG)
12 Motor generator (MG)
13 Transmission 14 Differential (differential)
15, 15 'Axle shaft 16, 16' Drive wheel 17 Clutch actuator 18 Shift actuator 19 Battery 20 Starter 21 HV-ECU (vehicle drive source control device, torque reduction means)
22 MG-ECU and inverter 23 EG-ECU
24 AMT-ECU
25 Battery ECU
26 Indicator 31 Output shaft 32 Flywheel 33 Clutch element 34 Transmission input shaft 35-41, 49 Drive gear 42 Transmission output shaft 43-48 Driven gear 50 Rev idler gear shaft 51 Rev idler gear 52-54 Hub member 55-57 Sleeve Member 58 gear 60 MG output shaft 61 driving gear 62 intermediate reduction shaft 63 driven gear 64 second driving gear 65 resolver (detecting means)
66 Stator member 67 Rotor member 70 Ring gear (final gear)

Claims (4)

A drive source control device for a vehicle, which includes an engine and a motor as drive sources, and performs torque assist by the motor at an instruction torque according to an accelerator opening degree when starting,
Detecting means for detecting wheel slip during the torque assist;
Torque reduction means for reducing the assist torque of the motor when a slip of the wheel is detected compared to when the slip is not detected,
A vehicle drive source control device. The detecting means detects slip of the wheel by a change in the number of rotations detected by a rotation detection sensor provided at one end of an output shaft of the motor;
The vehicle drive source control device according to claim 1. The torque reduction means reduces the assist torque of the motor according to the slip amount of the wheel;
The vehicle drive source control device according to claim 1 or 2, wherein Furthermore, it comprises means for executing power regeneration control for regenerating the kinetic energy of the vehicle as power,
When the slip amount of the wheel exceeds a predetermined threshold, the assist torque of the motor is suddenly reduced, and power regeneration control is executed to absorb torque.
The vehicle drive source control device according to any one of claims 1 to 3.

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