JP2006044549A - Hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid vehicle capable of speedily bringing the slipping of a driving wheel to a stop when the slipping occurs. <P>SOLUTION: A first clutch 3 is interposed between a rear wheel 11 and an engine 1, and a second clutch 31 is interposed between a front wheel 39 and the engine 1. Engaging force of the second clutch 31 is increased when it is judged that the rear wheel 11 slips when the vehicle travels by transmitting driving force of the engine 1 to the rear wheel 11 in a state of releasing the second clutch 31 between the engine 1 and the front wheel 39 and engaging the first clutch 3 between the engine 1 and the rear wheel 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hybrid vehicle including an engine and a motor as a driving force source for the vehicle.

  In a hybrid vehicle including an engine and a motor generator as a driving force source of the vehicle, it is possible to improve the fuel efficiency as compared with a conventional engine vehicle by utilizing the characteristics of the engine and the motor generator. Further, if the motor generator is regenerated to consume a part of the engine output when the driving wheel slips, the driving force transmitted to the driving wheel can be reduced, and slipping of the driving wheel can be suppressed.

In the hybrid vehicle disclosed in Patent Document 1, the driving force of the engine is transmitted to the front wheels and also to the generator, and when the front wheels slip, the generator consumes a part of the engine output and the front wheels The driving force transmitted to the vehicle is reduced to prevent the front wheel from slipping. Furthermore, the electric power regenerated by the generator is supplied to a motor connected to the rear wheels so as to drive the rear wheels.
JP 2001-63392 A

  However, when slip is suppressed by regenerating the motor generator, there is a time delay from the detection of the slip until the engine power is actually consumed and the driving force transmitted to the drive wheels is reduced. There was a problem that it was difficult to converge the slip.

  Further, like the hybrid vehicle disclosed in Patent Document 1, if the driving force is distributed to the rear wheels by supplying regenerative power to the motor connected to the rear wheels, the driving force transmitted to the front wheels is increased. Although it can be further reduced and the slip suppression effect can be enhanced, there is a two-stage conversion between driving force and power energy from when the slip is detected until the driving force is actually transmitted to the rear wheels. It was difficult to distribute the driving force to the rear wheels with high responsiveness and high efficiency, and to transmit the driving force to the road surface efficiently.

  The present invention has been made in view of such technical problems, and when a slip of a driving wheel occurs in a hybrid vehicle, the slip is quickly converged, and in such a situation, the driving force is efficiently applied to the road surface. The purpose is to be able to communicate.

  In the hybrid vehicle according to the present invention, the first clutch is interposed between the first drive wheel (for example, the rear wheel) and the engine, and between the second drive wheel (for example, the front wheel) and the engine. A second clutch is interposed. When slipping of the first driving wheel is determined when the driving force of the engine is transmitted to the first driving wheel while the second clutch is released and the first clutch is engaged, Increase the fastening force of the second clutch.

  By engaging the second clutch, part of the driving force of the engine that has been transmitted to the first drive wheel until then is also transmitted to the second drive wheel. Since there is no conversion process between driving force and electric energy as in the prior art, the driving force transmitted to the first driving wheel can be immediately reduced and the slip of the first driving wheel can be quickly converged. In addition, by distributing the driving force to the second driving wheels, the driving force can be efficiently transmitted to the road surface.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  Embodiments of the present invention will be described with reference to the accompanying drawings. Here, the configuration in which the rear wheels are mainly driven by the engine and the front wheels are mainly driven by the motor generator will be described as an example. However, this configuration may be reversed and the rear wheels are mainly driven by the motor generator and the front wheels are mainly driven by the engine. I do not care. The arrangement of the engine, motor generator, and transmission is not limited to the configuration described below.

  FIG. 1 shows a schematic configuration of a hybrid vehicle according to the present invention. The vehicle includes an engine 1 and a motor generator 41 as driving force sources. For example, the engine 1 is an internal combustion engine such as a gasoline engine or a diesel engine, and the motor generator 41 is a three-phase AC motor.

  The power train is divided into a rear wheel side and a front wheel side. The rear wheel side is connected to the engine 1 via the first clutch 3 with the propeller shaft 5, the first transmission 7, the first differential gear 9, the rear wheels ( A first drive wheel) 11 is connected. When the first clutch 3 is engaged, the driving force of the engine 1 is transmitted to the rear wheels 11 through these elements. By adopting a so-called transaxle system in which the first transmission 7 is arranged in the vicinity of the rear axle, the rear axle load is increased and transmitted to the road surface as compared with a general rear wheel drive system in which the transmission is arranged in the vicinity of the front axle. The possible driving force can be increased. In addition, since the front / rear weight distribution is improved, the exercise performance can be improved.

  Regarding the front wheel side, the input shaft 33, the second transmission 35, the second differential gear 37, and the front wheels (second drive wheels) 39 arranged coaxially with the propeller shaft 5 via the second clutch 31 in the engine 1. Is connected, and when the second clutch 31 is engaged, the driving force of the engine 1 is transmitted to the front wheels 39 via these elements. When both the first clutch 3 and the second clutch 31 are engaged, the driving force of the engine 1 is transmitted not only to the rear wheels 11 but also to the front wheels 39, and mechanical four-wheel drive can be realized. .

  A motor generator 41 is further connected to the input shaft 33 between the second clutch 31 and the second transmission 35, and a battery 45 is connected to the motor generator 41 via an inverter 43. If power is supplied from the battery 45 to the motor generator 41 and the motor generator 41 is powered (operated as a motor), the front wheels 39 can be driven via the input shaft 33 and the second transmission 35. Further, if the motor generator 41 is regeneratively operated (operates as a generator) during braking, the braking energy can be recovered and the battery 45 can be charged.

  If the second clutch 31 is released, the rear wheel 11 is driven by the engine 1, and the front wheel 39 is driven by the motor generator 41, the electric four wheels using the driving force of both the engine 1 and the motor generator 41 are used. Driving can be realized.

  In this embodiment, the first clutch 3 and the second clutch 31 are hydraulic clutches that can adjust the fastening force by adjusting the supply hydraulic pressure, but the configuration of the clutch is not limited to this, For example, instead of the hydraulic clutch, an electromagnetic clutch whose fastening force can be adjusted by a current value may be used.

  The second transmission 35 includes a first gear train 51 and a second gear train 53, and a dog clutch 55 for switching which of the first and second gear trains is connected to the input shaft 33. Is done. When the dog clutch 55 is displaced to the engine side, the first gear train 51 is connected to the input shaft 33, and the driving force is transmitted via the first gear train 51. Conversely, if the dog clutch 55 is displaced to the first transmission 7 side in the figure, the second gear train 53 is connected to the input shaft 33, and the driving force is transmitted via the second gear train 53.

  The vehicle is provided with a controller 60 for vehicle control. The controller 60 includes one or more microprocessors, an input / output interface, a memory, and the like, and includes a front wheel rotation speed sensor 61 that detects the rotation speed of the front wheel 39 and a rear wheel rotation speed sensor that detects the rotation speed of the rear wheel 11. 62, an accelerator operation amount sensor 63 for detecting the operation amount of the accelerator pedal, an engine rotation speed sensor 64 for detecting the rotation speed of the engine 1, a longitudinal acceleration sensor 65 for detecting the longitudinal acceleration of the vehicle, an oil temperature sensor (not shown), and the like. A signal is input.

  The controller 60 determines the slip state (slip rate, slip margin) of the front wheels 39 and the rear wheels 11 based on these input signals, and determines the control mode of the vehicle. Then, in accordance with the selected control mode, cooperative control of the engine 1, the motor generator 41, the first and second clutches 3 and 31 is performed. In the cooperative control, the target torque of the engine 1 and the motor generator 41 and the target hydraulic pressure of the first clutch 3 and the second clutch 31 are calculated, and the torque servos of the engine 1 and the motor generator 41 are achieved so that the calculated target values are achieved. Control and hydraulic servo control of the first and second clutches 3 and 31 are performed.

  The controller 60 periodically causes a current to flow to each sensor to generate a voltage drop, and compares the value with the normal case to determine signal path disconnection, short circuit, sensor abnormality, and signal path When disconnection or the like is found, the second clutch 31 is released and the cooperative control is stopped.

  FIG. 2 is a flowchart showing the contents of the control performed by the controller 60, and is executed by the controller 60 every predetermined time, for example, every 10 msec.

  The control contents of the controller 60 will be described with reference to this. First, in step S1, front and rear wheel slip rates Swf and Swr and front and rear wheel slip margins Smf and Smr are calculated. If the wheel speed of the front wheel 39 is Vwf and the vehicle body speed is Vb, the slip ratio Swf and the slip margin Smf of the front wheel 39 are calculated by the following equations.

Swf = (Vwf−Vb) / Vb
Smf = 0.1-Swf
The wheel speed Vwf of the front wheel 39 can be obtained by multiplying the value obtained by multiplying the tire diameter by 2π by the rotational speed Nf of the front wheel 39 detected by the sensor 61, and the vehicle body speed Vb is obtained by multiplying the wheel speed Vwf of the front wheel 39 with the rear wheel speed Vwf. It can be obtained as an average of the wheel speed Vwr of the wheel 11. Similarly, the slip ratio Swr and slip margin Smr of the rear wheel 11 can be calculated.

  In the following description, the slip of the front wheel 39 or the rear wheel 11 means that the slip margin of the wheel becomes less than zero (the slip ratio exceeds 0.1). It means that the margin becomes zero or more (the slip ratio becomes 0.1 or less).

  In step S <b> 2, it is determined whether a shift command is issued to the first transmission 7 and the second transmission 35. When a shift command is issued to either the first transmission 7 or the second transmission 35, the routine proceeds to step S3 and shift control is executed, and when no shift command is issued to either, the process proceeds to step S4. move on.

  In step S4, an idle stop start control mode, an acceleration driving force control mode, or a fully open acceleration driving force control mode is selected as a vehicle control mode based on the engine rotation speed Ne, the accelerator operation amount APO, and the engine torque Te. .

  The idle stop start control mode is a control mode used when the motor generator 41 is powered by starting from an idle stop state in which the engine 1 is stopped. In this control mode, the driving force from the motor generator 41 is applied to the front wheels. When slip occurs on the front wheel 39 so that the vehicle is efficiently transmitted to the road surface without causing slippage of the engine 39, a part of the driving force of the motor generator 41 is used for cranking of the engine 1 and consumed. By transmitting to the rear wheel 11, the slip of the front wheel 39 is suppressed.

  The acceleration driving force control mode is a control mode in which the driving force of the engine 1 is transmitted only to the rear wheels 11 by releasing the second clutch 31. This control mode is selected immediately after engine startup when engine torque is not stable or during normal travel. The normal travel refers to a travel state except immediately after the start when the idle stop start control mode is selected and when the fully open acceleration driving force control mode described later is selected.

  Further, the fully open acceleration driving force control mode is selected when the accelerator pedal is greatly depressed, and when it is difficult to transmit the driving force of the engine 1 to the road surface only by the rear wheels 11, the driving force of the engine 1 is selected. This is a control mode for suppressing the slip of the rear wheel 11 by transmitting the motor to the front wheel 39 and regenerating the motor generator 41 for consumption. The determination of the control mode is performed according to a flowchart shown in FIG.

  In step S5, the torque target values of the motor generator 41 and the engine 1 and the target hydraulic pressures of the first and second clutches 3 and 31 are set according to the control mode determined in step S4. A specific setting method will be described later.

  In step S6, torque servo control of the motor generator 41 is performed so that the torque of the motor generator 41 follows the motor generator torque target value set in step S5. In step S7, the torque of the engine 1 is set in step S5. Torque servo control of the engine 1 is performed so as to follow the engine torque target value.

  In step S8, hydraulic servo control is performed so that the hydraulic pressure supplied to the first clutch 3 follows the first clutch target hydraulic pressure set in step S5. Similarly, in step S9, the second clutch 31 is applied to the second clutch 31. Hydraulic servo control is performed so that the supplied hydraulic pressure follows the second clutch target hydraulic pressure set in step S5.

  FIG. 3 is a flowchart showing the contents of the control mode determination performed in step S4 of FIG. The control mode is determined based on the engine rotation speed Ne, the accelerator operation amount APO, and the engine torque Te. The engine torque Te can be obtained by referring to an engine torque map (not shown) based on the engine rotation speed Ne and the accelerator operation amount APO.

  According to this, first, in step S11, the engine rotational speed Ne is smaller than the predetermined low rotational speed Neth, the accelerator operation amount APO is larger than the predetermined small operation amount APOth1 (= the accelerator pedal is depressed), Further, it is determined whether the engine torque Te is smaller than a predetermined low torque Teth1 (= the torque of the engine 1 is not stable). If all the conditions are satisfied, the process proceeds to step S12, and the idle stop start control mode is selected as the vehicle control mode.

  If either condition is not satisfied, the process proceeds to step S13, where the engine rotational speed Ne is greater than the predetermined low rotational speed Neth, and the accelerator operation amount APO is between the predetermined small operation amount APOth1 and the predetermined large operation amount APOth2. It is determined whether the engine torque Te is smaller than a predetermined low torque Teth1 (= the torque of the engine 1 is not stable). If all the conditions are satisfied, the process proceeds to step S14, and the acceleration driving force control mode is selected as the vehicle control mode.

  If any of the conditions is not satisfied, the process proceeds to step S15, where the engine rotational speed Ne is greater than a predetermined low rotational speed Neth, the accelerator operation amount APO is greater than a predetermined large operation amount APOth2 (= accelerator fully open), and It is determined whether the engine torque Te is larger than the predetermined large torque Teth2 (= the torque of the engine 1 is stable). If all the conditions are satisfied, the process proceeds to step S16, and the fully open acceleration driving force is set as the vehicle control mode. If the control mode is selected and either condition is not satisfied, the process proceeds to step S14, and the acceleration driving force control mode is selected as the vehicle control mode.

  Next, a method for calculating the motor generator torque target value, the engine torque target value, and the target hydraulic pressure of the first and second clutches in each control mode will be described with reference to a block diagram.

1. Idle stop start control mode In the idle stop start control mode, the engine 1 is stopped and the vehicle is started and driven only by the driving force of the motor generator 41. Therefore, the torque target value of the engine 1 is not calculated and the motor generator torque target is not calculated. Only the value, the first and second clutch target oil pressures are calculated.

  FIG. 4 is a block diagram showing the contents of the motor generator target value calculation process. Similar to the flowcharts shown in FIGS. 2 and 3, the calculation is performed at predetermined time intervals, for example, every 10 msec (the same applies to other block diagrams).

  According to this, in block B1, when the accelerator operation amount APO is input, the motor generator target driving force is calculated with reference to a table that defines the relationship between the accelerator operation amount APO and the motor generator target driving force. In the table, the accelerator operation amount APO and the motor generator target driving force are in a proportional relationship, and the larger the accelerator operation amount APO is, the larger the motor generator target driving force is calculated. The table is preferably corrected in accordance with the vehicle speed, the gear position of the second transmission 35, and the oil temperature so that the deviation between the driving force requested by the driver and the table reference value is reduced.

  In block B2, the motor generator target driving force input from block B1 is converted into torque, and the motor generator torque target value is calculated. Specifically, the motor generator target driving force is converted into a torque target value by the following equation.

Motor generator torque target value = (tire diameter × motor generator target driving force) / (transmission ratio of second transmission 35 × front wheel final reduction ratio)
FIG. 5 is a block diagram showing the contents of the calculation process of the first clutch target hydraulic pressure. When the front wheel slip margin is input, the block B3 determines whether or not the front wheel slip margin exceeds zero. If the front wheel slip margin exceeds zero, the block B3 outputs zero, and if it is less than zero, the front wheel slip margin is output as it is.

In block B4, the limited front wheel slip margin is defined as a deviation e, and the amount of change in the first clutch target hydraulic pressure corresponding to the deviation e is calculated. The current value e _n of the deviation e, e _n-1 the previous value, when the second preceding value and e _n-2, the amount of change in the first clutch target pressure is calculated by the following equation.

The first clutch target pressure change amount = - (100 / PB) × {(e n -e n-1) + (ΔT / Ti) × e n + (Td / ΔT) × (e n -2e n-1 + En _-2 )}
PB is a proportional band [%], Ti is an integration time [sec], Td is a differentiation time [sec], ΔT is a calculation cycle [sec], and each parameter is set to a predetermined value with the clutch oil temperature of the first clutch 3 as an input. Requested by referring to the table. When the deviation e is present, that is, when the front wheel 39 is slipping, a positive value is output as the amount of change in the first clutch target hydraulic pressure.

  In block B5, a value obtained by adding the change amount of the first clutch target hydraulic pressure calculated in block B4 to the previous value of the first clutch target hydraulic pressure is output as the first clutch target hydraulic pressure.

  In block B6, the first clutch target hydraulic pressure calculated in block B5 is limited by setting the fully engaged hydraulic pressure of the first clutch 3 as the upper limit and zero as the lower limit, and the value after the limit is the final first clutch target hydraulic pressure. Output as hydraulic pressure.

  Therefore, when the front wheel 39 is not slipping, the first clutch target hydraulic pressure is zero and the first clutch 3 is released. When the front wheel 39 slips, the target hydraulic pressure of the first clutch 3 increases as the slip margin decreases, that is, the slip rate of the front wheel 39 increases, and the engagement force of the first clutch 3 increases.

  FIG. 6 is a block diagram showing the contents of the calculation process of the second clutch target hydraulic pressure. The timer of block B7 is started at the timing when the vehicle starts (for example, when the accelerator pedal is depressed), and the count value of the timer is output to block B8. In block B8, the second clutch target hydraulic pressure is calculated and output with reference to a predetermined boost curve table based on the count value of the timer. The second clutch target hydraulic pressure increases as the count value increases, and takes a constant value when the count value reaches a certain value.

  In block B9, when the front wheel slip margin is input, it is determined whether the front wheel slip margin exceeds zero. If it exceeds zero, zero is output, and if it is less than zero, the front wheel slip margin is output as it is.

  In block B10, the amount of change in the second clutch target hydraulic pressure is calculated and output in the same manner as in block B4, with the limited front wheel slip margin input from block B9 as the deviation e. When the deviation e is present, that is, when the front wheel 39 is slipping, a positive value is output as the amount of change in the second clutch target hydraulic pressure.

  The addition / subtraction unit A1 outputs the output of the block B8 plus the output of the block B10. In the block B11, the full engagement hydraulic pressure of the second clutch 31 is limited to the upper limit and zero is set to the lower limit. The later value is output as the second clutch target hydraulic pressure.

  Therefore, when the front wheel 39 is not slipping, the second clutch target hydraulic pressure rises to a certain value and takes a constant value (= constant engaging force). Then, when the front wheel 39 starts to slip and the slip margin becomes smaller than zero, the target hydraulic pressure of the second clutch 31 is increased and the engaging force of the second clutch 31 is increased.

  FIG. 7 is a time chart showing a state in which the vehicle is running in the idle stop start control mode, and the vehicle is started from the stop state by causing the motor generator 41 to power. At this time, the engine 1 remains stopped.

  As the vehicle starts to start, the slip rate of the front wheels 39 starts to increase. At this time, the hydraulic pressure of the second clutch 31 also increases, and the second clutch 31 enters a half-clutch state and the engine 1 is cranked.

  Thereafter, as the torque of the motor generator 41 increases, when the slip rate of the front wheel 39 exceeds the slip limit and begins to slip, the clutch hydraulic pressures of the first and second clutches 3 and 31 are both increased, and the fastening force is increased. A part of the driving force of the motor generator 41 is transmitted to the rear wheels 11 and is also consumed for cranking the engine 1. The hydraulic pressures of the first and second clutches 3 and 31 are increased at the same time because, in order to transmit the driving force of the motor generator 41 to the rear wheels 11 due to the configuration of the power train, both clutches are engaged. It is necessary to keep.

  A part of the driving force of the motor generator 41 is also distributed to the rear wheels 11 and consumed for cranking the engine 1, so that the driving force transmitted to the front wheels 39 is reduced, and the slip of the front wheels 39 is reduced. Converge quickly. Further, by transmitting a part of the driving force to the rear wheel 11, the driving force of the motor generator 41 can be transmitted to the road surface without waste.

  In the time chart and the block diagrams shown in FIGS. 5 and 6, when the front wheel 39 slips, the hydraulic pressures of the first clutch 3 and the second clutch 31 are increased at the same time. The timing for increasing the hydraulic pressure of the clutch 3 may be delayed from the timing for increasing the hydraulic pressure of the second clutch 31. If the increase in the hydraulic pressure of the first clutch 3 is delayed, when the driving force of the motor generator 41 is transmitted to the rear wheel 11, the fastening force of the second clutch 31 is insufficient and cannot be transmitted to the rear wheel 11. The situation can be avoided.

2. Acceleration driving force control mode The acceleration driving force control mode is a mode that is selected when the torque of the engine 1 is low and unstable, or during normal running except when starting or accelerating fully open, and the second clutch 31 is released. The driving force of the engine 1 is mainly transmitted to the rear wheel 11.

  FIG. 8 is a block diagram showing the contents of the calculation processing of the motor generator torque target value and the engine torque target value.

  When the accelerator operation amount APO is input, the block B21 calculates a target vehicle driving force with reference to a table that defines the relationship between the accelerator operation amount APO and the target vehicle driving force. In this table, the accelerator operation amount APO and the target vehicle driving force are in a proportional relationship, and the larger the accelerator operation amount APO is, the larger the target vehicle driving force is calculated. The table is preferably corrected according to the vehicle speed, the gear position and oil temperature of the first transmission 7, the gear speed and oil temperature of the second transmission 35, and the driving force requested by the driver and the table reference value The deviation is reduced.

  In block B22, the target vehicle driving force is multiplied by the tire diameter to be converted into torque, and this is output as the target vehicle torque.

  In block B23, the distribution ratio of the driving force of the engine 1 and the motor generator 41 is obtained by referring to the distribution ratio table based on the vehicle longitudinal acceleration. Based on the gear ratio of the second transmission 35, the front wheel final reduction ratio, the gear position of the first transmission 7, and the rear wheel final reduction ratio, the motor generator torque target value and the engine torque target value are calculated by the following equations, respectively. To do.

Motor generator torque target value = (MG distribution ratio × target vehicle torque) / (speed ratio of second transmission 35 × front wheel final reduction ratio)
Engine torque target value = (engine distribution ratio × target vehicle torque) / (speed ratio of first transmission 7 × rear wheel final reduction ratio)
When the front wheel slip margin is input, the block B24 determines whether the front wheel slip margin exceeds zero, outputs zero if it exceeds zero, and outputs the front wheel slip margin as it is if it is less than zero.

  In block B25, similarly to block B4, the amount of change in the motor generator torque target value is calculated and output with the limited front wheel slip margin as the deviation e. When the deviation e is present, that is, when the front wheel 39 is slipping, a positive value is output.

  The addition / subtraction unit A2 subtracts the amount of change input from the block B25 from the motor generator torque target value input from the block B23, and outputs this as the motor generator torque target value.

  In block B26, the rear wheel slip margin is input. If the rear wheel slip margin exceeds zero, zero is output, and if it is less than zero, the rear wheel slip margin is output as it is. In block B27, the amount of change in the engine torque target value is calculated using the rear wheel slip margin as the deviation e, and in the addition / subtraction unit A3, the amount of change calculated in block B27 is subtracted from the engine torque target value input from block B23, This is output as an engine torque target value.

  FIG. 9 is a block diagram showing the contents of the calculation process of the first clutch target hydraulic pressure.

  When the rear wheel slip margin is input, the block B31 determines whether the rear wheel slip margin exceeds zero, outputs zero if it exceeds zero, and outputs the rear wheel slip margin as it is if it is less than zero.

  In block B32, the amount of change in the first clutch target hydraulic pressure is output in the same manner as in block B4, with the limited rear wheel slip margin input from block B31 as the deviation e. When the deviation e is present, that is, when the rear wheel 11 is slipping, a positive value is output as the amount of change in the first clutch target hydraulic pressure.

  In the addition / subtraction unit A4, the amount of change input from the block B32 is subtracted from the complete engagement hydraulic pressure of the first clutch 3, and in the block B33, this is limited by limiting the complete engagement hydraulic pressure of the first clutch 3 as the upper limit and zero as the lower limit. The later value is output as the first clutch target hydraulic pressure.

  Therefore, the first clutch target hydraulic pressure is set to the fully engaged hydraulic pressure when the rear wheel 11 is not slipped, and the driving force transmitted to the rear wheel 11 is reduced when the rear wheel 11 is slipped. In order to suppress the slip, the target hydraulic pressure of the first clutch 3 is lowered from the fully engaged hydraulic pressure in accordance with the slip margin of the rear wheel.

  FIG. 10 is a block diagram showing the contents of the calculation process of the second clutch target hydraulic pressure.

  The timer of the block B34 is started at the timing when the acceleration driving force control mode is selected, and the count value of the timer is output to the block B35.

  The hydraulic pressure of the second clutch 31 immediately before the acceleration driving force control mode is selected is input to the block B35, and based on this and the count value of the timer input from the block B34, the predetermined pressure reduction curve table is referred to. 2-clutch target hydraulic pressure is calculated. The second clutch target hydraulic pressure is calculated so as to decrease from the value immediately before the acceleration driving force control mode is selected according to the elapsed time after the acceleration driving force control mode is selected.

  In block B36, the second clutch target hydraulic pressure calculated in block B35 is limited with the fully engaged hydraulic pressure of the second clutch 31 as the upper limit and zero as the lower limit, and the post-limit value is output as the second clutch target hydraulic pressure.

  Therefore, the second clutch target hydraulic pressure starts to decrease when the acceleration driving force control mode is entered, eventually becomes zero, and the second clutch 31 is released.

  FIG. 11 is a time chart showing a state in which the vehicle is running in the acceleration driving force control mode, and it is not long after the engine 1 is started with both the first clutch 3 and the second clutch 31 engaged. Is shown.

  When the acceleration driving force control mode is entered, the hydraulic pressure of the second clutch 31 decreases according to the elapsed time from the entered timing, and the second clutch 31 is released. As a result, the torque of the engine 1 that has become unstable immediately after starting is not input to the front wheels 39. In a situation where the traction control is performed using the motor generator 41 so that the slip ratio of the front wheels 39 approaches the slip limit and the traction is maximized, unstable engine torque is transmitted to the front wheels 39. As a result, it is possible to avoid a decrease in the accuracy of the traction control.

3. Full-open acceleration driving force control mode The full-open acceleration driving force control mode is a control mode that is selected when the accelerator pedal is greatly depressed. In this control mode, when the driving force of the engine 1 increases and slip occurs in the rear wheel 11, the second clutch 31 is engaged so that a part of the driving force of the engine 1 is transmitted to the front wheels 39, Further, by causing the motor generator 41 to perform a regenerative operation and consuming part of the driving force of the engine 1, the slip of the rear wheel 11 is quickly converged.

  FIG. 12 is a block diagram showing the contents of the engine torque target value calculation process.

  In block B41, when the accelerator operation amount APO is input, the engine target driving force is calculated with reference to a table that defines the relationship between the accelerator operation amount APO and the engine target driving force. In the table, the accelerator operation amount APO and the engine target driving force are in a proportional relationship, and the larger the accelerator operation amount APO is, the larger the engine target driving force is calculated. The table is preferably corrected in accordance with the vehicle speed, the gear position of the first transmission 7 and the oil temperature, so that the deviation between the driving force requested by the driver and the table reference value is reduced.

  In block B42, the engine target driving force is converted into torque, and the engine torque target value is calculated. Specifically, the target driving force is converted into a torque target value by the following equation.

Engine torque target value = (tire diameter × engine target driving force) / (speed ratio of first transmission 7 × rear wheel final reduction ratio)
When the rear wheel slip margin is input, the block B43 determines whether the rear wheel slip margin exceeds zero, outputs zero if it exceeds zero, and outputs the rear wheel slip margin as it is if it is less than zero. .

  In block B44, similarly to block B4, the amount of change in the motor generator torque target value is calculated and output with the rear wheel slip margin as the deviation e. When there is a deviation e, that is, when the rear wheel 11 is slipping, a positive value is output.

  The addition / subtraction unit A5 outputs a value obtained by adding the amount of change calculated in block B12 to the engine torque target value calculated in step B42 as the engine torque target value. The engine torque target value is increased in spite of the situation where the rear wheel 11 is slipping, as will be described later, when the rear wheel 11 is slipping, the second clutch 31 is engaged and the motor generator 41 is turned on. Since the regenerative operation is performed, the driving force transmitted to the road surface in response to this is not greatly reduced. Even if the engine torque target value is increased, the driving force of the engine 1 is distributed to the front wheels 39 and the rear wheels 11, so that the slip of the rear wheels 11 does not increase.

  FIG. 13 is a block diagram showing the contents of the motor generator torque target value calculation process.

  When the rear wheel slip margin is input, the block B45 determines whether the rear wheel slip margin exceeds zero, outputs zero if it exceeds zero, and outputs the rear wheel slip margin as it is if it is less than zero. .

  In block B46, similarly to block B4, the amount of change in the motor generator torque target value is calculated and output with the rear wheel slip margin as the deviation e. When there is a deviation e, that is, when the rear wheel 11 is slipping, a positive value is output.

  In block B47, the motor generator torque target value is calculated by subtracting the change amount of the motor generator torque target value calculated in block B46 from the previous value of the motor generator torque target value. When there is a deviation e, that is, when the rear wheel 11 starts to slip, the motor generator torque target value decreases and takes a negative value, and the motor generator 41 starts the regenerative operation.

  FIG. 14 is a block diagram showing the contents of the calculation process of the first clutch target hydraulic pressure.

  The timer of block B51 is started at the timing when the fully open acceleration driving force control mode is selected, and the count value of the timer is output to block B52.

  The hydraulic pressure of the first clutch 3 immediately before entering the fully open acceleration driving force control mode is input to the block B52. Based on this and the count value of the timer input from the block B51, the first clutch target is referred to by referring to the boost curve table. Calculate the amount of change in hydraulic pressure. The amount of change in the first clutch target hydraulic pressure is calculated so as to increase in accordance with the elapsed time since the acceleration driving force control mode was selected from the value immediately before entering the fully open acceleration driving force control mode.

  In the addition / subtraction unit A6, the amount of change calculated in the block B52 is added to the hydraulic pressure of the first clutch 3 immediately before entering the fully open acceleration driving force control mode, and output. In block B53, this is limited with the fully engaged hydraulic pressure of the first clutch 3 as the upper limit and zero as the lower limit, and the value after limitation is output as the first clutch target hydraulic pressure.

  Therefore, when the fully open acceleration driving force control mode is entered, the hydraulic pressure of the first clutch 3 increases as time passes and rises to the fully engaged hydraulic pressure, and is in a fully engaged state.

  FIG. 15 is a block diagram showing the contents of the calculation process of the second clutch target hydraulic pressure.

  When the rear wheel slip margin is input, the block B55 determines whether the rear wheel slip margin exceeds zero, outputs zero if it exceeds zero, and outputs the rear wheel slip margin as it is if it is less than zero. .

  In block B56, as in block B4, the amount of change in the second clutch target hydraulic pressure is calculated with the post-limit rear wheel slip margin as the deviation e. When the deviation e is present, that is, when the front wheel 39 is slipping, a positive value is output.

  In block B57, the second clutch target hydraulic pressure is calculated by adding the change amount of the second clutch target hydraulic pressure calculated in block B56 to the previous value of the second clutch target hydraulic pressure. In block B57, this is limited with the fully engaged hydraulic pressure of the second clutch 31 as the upper limit and zero as the lower limit, and the value after the limitation is output as the second clutch target hydraulic pressure.

  Therefore, when the fully open acceleration driving force control mode is entered, as the slip of the rear wheel 11 increases, the hydraulic pressure of the second clutch 31 increases and the fastening force increases.

  FIG. 16 is a time chart showing a state when the vehicle is traveling in the fully open acceleration driving force control mode.

  When the slip ratio of the rear wheel 11 exceeds the slip limit and begins to slip, the hydraulic pressure of the second clutch 31 is increased, and a part of the driving force of the engine 1 that has been transmitted to the rear wheel 11 until then is also transferred to the front wheel 39. Be transmitted. Further, the motor generator 41 starts a regenerative operation, and this also consumes a part of the driving force of the engine 1.

  As a result, the driving force transmitted to the rear wheel 11 is reduced, and the slip of the rear wheel 11 is suppressed. By engaging the second clutch 31, a part of the driving force of the engine 1 is transmitted to the front wheels 39 without undergoing an electrical conversion process, so that the driving force transmitted to the rear wheels 11 is immediately reduced. The slip of the rear wheel 11 can be quickly converged.

  As mentioned above, although embodiment of this invention was described, it is as follows when the effect of this invention is put together.

  In the hybrid vehicle according to the present invention, the first clutch 3 is interposed between the first drive wheel (for example, the rear wheel) 11 and the engine 1, and the second drive wheel (for example, the front wheel) 39, the engine 1, A second clutch 31 is interposed between the two. When the second clutch 31 is disengaged and the first clutch 3 is engaged, the first driving wheel 11 slips when traveling with the driving force of the engine 1 transmitted to the first driving wheel 11. When it is determined that the second clutch 31 is engaged, the fastening force of the second clutch 31 is increased.

  By engaging the second clutch 31, a part of the driving force of the engine 1 that has been transmitted to the first driving wheel 11 until then is also transmitted to the second driving wheel 39, so that the first driving wheel The driving force transmitted to 11 can be immediately reduced, and the slip of the first driving wheel 11 can be quickly converged. Further, since the motor generator 41 is regeneratively operated at this time, the driving force of the engine 1 is consumed and the driving force transmitted to the first driving wheel 11 is further reduced, and the slip convergence effect can be further enhanced. .

  When starting the vehicle, the engine 1 is stopped and the first generator 3 and the second clutch 31 are released, and the motor generator 41 is powered to start the vehicle. After starting, the second drive wheel 39 slips. When it is determined that the second clutch 31 is engaged, the fastening force of the second clutch 31 is increased. Thereby, the driving force of the motor generator 41 is consumed by the cranking of the engine 1, and the slip of the second driving wheel 39 can be suppressed. At this time, if the fastening force of the first clutch is also increased, the driving force of the motor generator 41 is transmitted to the first driving wheel 11 and the driving force transmitted to the second driving wheel 39 is increased. Further, the slip suppression effect can be further increased. Since the driving force is mechanically transmitted to the first driving wheel 11, the driving force transmitted to the second driving wheel 39 immediately decreases, and the slip of the second driving wheel 39 converges quickly.

  Further, when the engine 1 is running with the first clutch 3 and the second clutch 31 engaged, when it is determined that the torque of the engine 1 is lower than a predetermined low torque, the engagement force of the second clutch 31 is increased. Try to decrease. As a result, the torque of the engine 1 that has become unstable due to, for example, immediately after starting is not input to the second drive wheel, and the traction control of the second drive wheel 39 is performed using the motor generator 41. In such a case, it is possible to avoid unstable traction control due to fluctuations in engine torque.

1 is an overall configuration diagram of a hybrid vehicle according to the present invention. It is the flowchart which showed the content of the control which a controller performs. It is the flowchart which showed the content of the control mode determination process which a controller performs. It is a block diagram for calculating a motor generator torque target value in the idle stop start control mode. It is a block diagram for calculating the first clutch target hydraulic pressure in the idle stop start control mode. FIG. 6 is a block diagram for calculating a second clutch target hydraulic pressure in an idle stop start control mode. It is the time chart which showed the mode when it drive | works in idle stop start control mode. It is a block diagram for calculating a motor generator torque target value and an engine torque target value in an acceleration driving force control mode. It is a block diagram for calculating the first clutch target hydraulic pressure in the acceleration driving force control mode. FIG. 6 is a block diagram for calculating a second clutch target hydraulic pressure in the acceleration driving force control mode. It is the time chart which showed the mode when it drive | works in acceleration driving force control mode. It is a block diagram for calculating an engine torque target value in the fully open acceleration driving force control mode. It is a block diagram for calculating a motor generator torque target value in a fully open acceleration driving force control mode. FIG. 6 is a block diagram for calculating a first clutch target hydraulic pressure in a fully open acceleration driving force control mode. FIG. 6 is a block diagram for calculating a second clutch target hydraulic pressure in a fully open acceleration driving force control mode. It is the time chart which showed the mode at the time of driving | running | working in a full open acceleration driving force control mode.

Explanation of symbols

1 Engine 3 First clutch 7 First transmission 11 Rear wheel (first drive wheel)
31 Second clutch 35 Second transmission 39 Front wheel (second drive wheel)
41 motor generator 43 inverter 45 motor generator 60 controller 61 front wheel acceleration sensor 62 rear wheel acceleration sensor 63 accelerator operation amount sensor 64 engine rotational speed sensor 65 longitudinal acceleration sensor

Claims (5)

Engine,
A first drive wheel;
A second drive wheel disposed on the front side or the rear side of the vehicle with respect to the first drive wheel;
A first clutch interposed between the first drive wheel and the engine;
A second clutch interposed between the second drive wheel and the engine;
A motor generator interposed between the second drive wheel and the second clutch;
Means for determining slip of the first drive wheel;
The first drive wheel slips when the engine is traveling with the driving force of the engine transmitted to the first drive wheel with the second clutch disengaged and the first clutch engaged. Control means for increasing the fastening force of the second clutch when it is determined that
A hybrid vehicle characterized by comprising:   2. The control unit according to claim 1, wherein when the slip of the first drive wheel is detected, the control unit causes the motor generator to perform a regenerative operation in addition to increasing the fastening force of the second clutch. Hybrid vehicle. Means for determining slip of the second drive wheel;
The control means starts the vehicle by starting the vehicle by powering the motor generator in a state where the engine is stopped and the first and second clutches are released at the time of starting the vehicle. The hybrid vehicle according to claim 1, wherein when it is determined that the vehicle is slipping, the fastening force of the second clutch is increased.   4. The hybrid according to claim 3, wherein, when it is determined that the second driving wheel is slipping, the control unit increases a fastening force of the first clutch in addition to the second clutch. 5. vehicle. Means for determining the torque of the engine;
The control means reduces the engagement force of the second clutch when it is determined that the engine torque is lower than a predetermined low torque during traveling with the first and second clutches engaged. The hybrid vehicle according to claim 1, wherein:

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