JP3896640B2 - Vehicle powertrain system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power train system for a vehicle.
[0002]
[Prior art]
A typical power train in a vehicle driven by an internal combustion engine has a configuration as shown in FIG. 23, for example.
That is, an automatic transmission 30 comprising a torque converter 3 and a transmission mechanism unit 5 is connected to the crankshaft 1 a of the engine 1, and then the output torque of the engine 1 is transmitted to the drive wheels 7 via the reduction / differential device unit 6. It has become so. A lockup clutch 4 is attached to the torque converter 3 of the automatic transmission. Further, an auxiliary machine 2 such as an air conditioner compressor, an alternator, a power steering pump, and an engine cooling water pump is connected to the crankshaft 1a of the engine.
[0003]
In a vehicle equipped with such a power train, during operation, for example, when stopping at an intersection, the engine 1 continues to drive the auxiliary machine 2 and generates a creep force in preparation for the next start in the travel range. Yes. Therefore, a predetermined amount of fuel is consumed even though the vehicle is not traveling.
[0004]
Therefore, in order to reduce fuel consumption during operation, it is conceivable to stop the fuel to the engine 1 while driving the auxiliary machine at the time of deceleration when the vehicle speed is high or the vehicle is locked up.
That is, during deceleration at high vehicle speed, the lock-up clutch 4 of the torque converter section is engaged to eliminate slipping in the torque converter 3 and stop fuel injection to the engine 1. As a result, so-called engine braking is applied, and the vehicle speed gradually decreases on a flat road.
[0005]
Although the speed change mechanism 5 shifts as the vehicle speed decreases, there is a limit to increase the gear ratio, and naturally the engine speed cannot be kept high when the vehicle speed decreases. As a result, when the vehicle is locked up, a vehicle speed region is generated in which the engine 1 becomes lower than the idling rotational speed and the engine stall (engine stall) is caused as the vehicle speed decreases. In addition, there is a case where the transmission ratio is excessively increased and the drivability is deteriorated by strong engine braking. Therefore, when entering an area where such engine stall or drivability deteriorates, the lockup is released.
[0006]
[Problems to be solved by the invention]
However, the fuel consumption saving method as described above has the following problems.
First, of course, if the vehicle does not lock up when decelerating, even if it is locked up as described above, the lockup must be released especially at low vehicle speeds. Due to this, the engine becomes lower. As a result, auxiliary functions such as air conditioner compressors, alternators, power steering pumps, and engine cooling water pumps are lost, and the oil pump of the automatic transmission stops and the internal forward clutch is disengaged. It becomes impossible.
And no creep force is generated.
[0007]
The oil pump driven by the engine 1 generates hydraulic pressure when the engine is started. As an initial state, when the internal clutch of the automatic transmission is not engaged, there is a time delay until the clutch is engaged. Since the power of the engine 1 is not transmitted, the delay time is obtained by adding the clutch delay time to the start delay time.
Also, even if the hydraulic pressure necessary for automatic transmission operation is secured by some means and power transmission is possible, the engine 1 is started when the accelerator pedal is depressed and reaccelerated in the decelerated state while being stalled. Since acceleration has to be started after that, the torque rise is still delayed for the time required for starting, and the drivability may be deteriorated.
[0008]
In this way, when the lockup is finally released during deceleration, the engine speed decreases rapidly and reaches the engine stall. To avoid this, the fuel injection is restarted and the engine engine stopped before the vehicle has stopped. Therefore, the purpose of saving fuel consumption cannot be fully achieved.
On the other hand, when the fuel injection is stopped and the engine 1 is finally stopped for the purpose of pursuing the fuel consumption reduction, the following problem occurs.
[0009]
That is, in general, when starting the engine, control is performed such that cranking is performed using a starter motor, and fuel is injected after cylinder (cylinder) discrimination is performed during cranking. When the engine is started by this method, there is a problem that the startability is poor because the fuel injection timing is delayed. Therefore, a method of storing the output value of the crank angle sensor indicating the cylinder position when the engine is stopped and identifying the cylinder from the start of the start based on the stored value and performing fuel injection control is conceivable.
[0010]
However, if the fuel injection is simply stopped and the engine rotation is stopped, the reverse rotation of the crankshaft 1a may occur at the final stage of engine stop, and the output value of the crank angle sensor may be stored. The cylinder which should inject fuel at the time of the next start will be mistakenly recognized. Therefore, it is impossible to accurately identify the cylinder position and inject fuel by optimal sequential control, and return to the conventional control described above, or the start of rotation is delayed, or all cylinders are injected with fuel and started. As a result, it consumes a lot of fuel, which is contrary to the purpose. This is also a problem that occurs regardless of whether or not fuel is stopped during deceleration.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle power train system that achieves a significant start-up while achieving a significant reduction in fuel consumption.
[0011]
[Means for Solving the Problems]
  Therefore, in the first aspect of the invention, the engine transmits the output of the crankshaft to the drive wheel through the transmission, the speed reducer, and the axle to be a power source for traveling the vehicle, and can be connected to the crankshaft by a clutch. A motor is attached and the engineAnd a control device that controls the transmission and includes engine speed control means.
[0012]
  AndThe control device stops the fuel supply to the engine during vehicle deceleration, and the engine speed control means reduces the engine speed so as to suppress the reverse rotation of the engine by controlling the transmission capacity of the clutch when the engine rotation is stopped. The state was to be controlled.
[0013]
The first motor is always connected to an engine accessory, and the control device motorizes the engine with the first motor during vehicle deceleration, and maintains the engine rotation state until the vehicle stops. it can.
In this case, it is preferable that the engine rotational speed control means gradually decrease the engine rotational speed from the rotational speed by motoring, and in this case, the transmission capacity is gradually decreased by duty-controlling the clutch.
[0014]
A second motor is connected to the rear stage of the transmission, and the control device is configured to regenerate vehicle deceleration energy by the second motor during vehicle deceleration and to apply a creep force by the second motor while the vehicle is stopped. be able to.
Furthermore, fuel is supplied to the engine by fuel injection. When the vehicle restarts, the clutch is engaged, the crankshaft is cranked by the first motor, and the engine is started by sequential injection based on the stop position of the engine. It is preferable to supply.
In addition, when the vehicle restarts, a driving force larger than the creep force can be applied by the second motor.
[0015]
[Action]
  In claim 1,By controlling the transmission capacity of the clutch between the crankshaft and the first motor, it is possible to control the engine cylinder stop position without errors by stopping the engine rotation, and it is effective for control at the time of restart Available.
[0016]
  AndBy stopping the fuel supply to the engine when the vehicle decelerates, fuel consumption during this period is also reduced.
[0017]
The first motor is always connected to the engine accessory, and the engine is motored by the first motor during vehicle deceleration, so that the engine rotation state is maintained until the vehicle stops. But it can be re-accelerated without restarting the engine.
In this case, in the control by the engine speed control means, the engine speed can be gradually changed from the motoring state and stopped by gradually decreasing the engine speed from the motoring speed.
In particular, it is easy to reduce the transmission capacity of the clutch by duty control and the control accuracy is good.
[0018]
In addition, by providing the second motor, the vehicle deceleration energy can be regenerated to obtain an appropriate deceleration feeling and the energy can be stored, while the second motor is driven based on the energy while the engine is stopped to creep. Can give power.
[0019]
Furthermore, when starting the engine, fuel is supplied by sequential injection based on the stop position of the engine, so that a good startability can be obtained and the fuel injection amount at the start can be reduced. Moreover, the starter motor can also be used by cranking with the first motor.
In addition, when the vehicle restarts, a driving force larger than the stopping creep force is applied by the second motor, so that the start of the vehicle starts quickly.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
The embodiment of the present invention will be described with reference to examples.
FIG. 1 is a skeleton diagram showing a power train in the embodiment.
On the one hand, an automatic transmission 30 comprising a torque converter 3, a lock-up clutch 4 and a transmission mechanism unit 5, a reduction / differential device unit 6, drive shafts 7 a and 7 b, and drive wheels 7 are sequentially connected to the engine 1. Are connected to auxiliary equipment 2 such as an air conditioner compressor, an alternator, a power steering pump, and an engine cooling water pump.
The engine 1 is supplied with fuel by a fuel injection valve (not shown).
Further, a first motor 9 that is connected to the auxiliary machine 2 and connectable to the engine 1 is provided, and a second motor 8 is connected to the speed reduction / differential device section 6 in parallel with the automatic transmission 30. .
[0021]
More specifically, the output of the engine 1 is transmitted to the speed change mechanism 5 via the torque converter 3 connected to the crankshaft 1a or the lockup clutch 4 connected in parallel with the torque converter 3 and further to the speed reduction / differential device 6 To the drive wheel 7 via the drive shafts 7a and 7b.
The second motor 8 is connected to the transaxle third shaft 6 a of the speed reduction / differential device section 6, and the output of the engine 1 and the output of the second motor 8 are merged by the third shaft to transmit power to the drive wheels 7. .
[0022]
On the other hand, the engine 1 is connected to a first motor 9 via an electromagnetic clutch 10 via a crank pulley 1b and a belt 9a attached to the crankshaft 1a. Further, the first motor 9 and the auxiliary machine 2 are connected to each other. It is connected by a belt 2a. When the clutch 10 is engaged, the engine 1 and the first motor 9 rotate in conjunction with each other at a constant rotation speed ratio.
[0023]
An auxiliary machine 2 such as an air conditioner compressor, an alternator, a power steering pump, an engine cooling water pump, etc., and a second motor 8 and a first motor 9 are supported by a block of the engine 1.
[0024]
Further, the automatic transmission 30 is provided with a hydraulic control unit 12. As shown in FIG. 2, an oil pump 20 for automatic transmission driven by the engine 1 and an oil pump 21 driven by a motor 25 are connected to the hydraulic control unit 12 so that the line pressure for operating the automatic transmission is reached. Is generated. Oil pressures of the oil pumps 20 and 21 are connected to the hydraulic control unit 12 via check valves 22 and 22, respectively, and the higher hydraulic pressure is output to the hydraulic control unit. Thereby, even when the engine 1 is stopped, the internal clutch 5a such as a forward clutch that is engaged when the automatic transmission 30 is engaged, for example, can be engaged, and power transmission is possible.
[0025]
FIG. 3 shows the configuration of the control device in the power train.
The control device includes an engine control unit 13, an automatic transmission control unit 14, and a hybrid system control unit 15, and operates with power supplied from a low voltage battery 29.
The engine control unit 13 controls the engine 1 by controlling the throttle opening, ignition timing, fuel injection valve, intake / exhaust valve, and the like based on information from various sensors including the accelerator opening and the idle switch state.
[0026]
The automatic transmission control unit 14 controls the automatic transmission 30 by controlling the lockup clutch 4 and other gear ratio control actuators based on information from various sensors including the shift lever selection position, engine speed, and vehicle speed. Control.
The hybrid system control unit 15 controls the clutch 10 or the motor-driven automatic transmission oil pump 21 based on information from various sensors including the idle switch state, the engine speed, the vehicle speed, and the brake switch state. The second motor 8 and the first motor 9 are controlled via the inverters 26 and 27. The second motor 8 and the first motor 9 are connected to a high voltage battery 28 via an inverter, and can take power from the high voltage battery 28 during drive control and can charge the high voltage battery 28 during regeneration control.
Further, in order to share information for cooperative control in addition to information from various sensors, the control units are connected by communication lines.
[0027]
Next, the transition of the control state during vehicle operation by the control device will be described. First, FIG. 4 is a time chart showing changes in each sensor signal and torque when decelerating from a state where the vehicle travels at a high speed and a constant speed.
When traveling at high speed, the fuel injection mode is in which fuel injection is performed and the engine 1 is being driven. However, in order to prevent slipping in the torque converter 3 and reduce fuel consumption, the lockup clutch 4 is engaged. Although the first motor 9 is not in the output state, the clutch 10 is engaged and rotated by the output of the engine 1 so that the auxiliary machine 2 is rotating. This corresponds to section A in the figure.
[0028]
Next, when the driver removes his or her foot from the accelerator pedal at time t1 and the idle switch is turned on, the engine control unit 13 determines that a deceleration state has been entered, and stops fuel injection to the engine 1.
As a result, the engine 1 is reversely driven from the drive wheels 7, the axle torque becomes the driven side, and the engine braking effect expressed by the lockup (L / U) axle torque is generated, and the lockup (L / U) of the B section is generated. ) Move to deceleration mode.
[0029]
Subsequently, when the driver depresses the brake pedal at time t2 and the brake switch is turned on, the hybrid system control unit 15 obtains the target axle torque corresponding to the vehicle speed from the map as shown in FIG. 5 in order to obtain the necessary deceleration. The amount of the lockup axle torque that is insufficient with respect to the target axle torque is supplemented by the regenerative axle torque by the second motor 8.
[0030]
That is, the engine friction torque is obtained from the engine friction map of FIG. 6, and the engine friction axle torque converted to the axle torque is calculated in consideration of the selected gear ratio. Further, the transmission friction axle torque converted to the axle is calculated from the transmission friction map of FIG. 7 in consideration of the engine speed and the gear ratio.
These engine friction axle torque and transmission friction axle torque become lockup axle torque, and the regenerative axle torque is obtained by subtracting the lockup axle torque from the target axle torque.
[0031]
During this time, the engine 1 continues to rotate and the auxiliary machine 2 is rotated by the engine output, so the auxiliary machine function continues. Further, since the oil pump 20 of the automatic transmission is also driven by the engine output, the internal clutch 5a of the automatic transmission 30 can be engaged and the power transmission function continues. Therefore, since the engine 1 is rotating during this deceleration, when reaccelerating, the time required for cranking for restarting is unnecessary and fuel injection can be executed immediately, and there is no fear of a delay in rising of the driving force.
[0032]
Next, when the vehicle speed decreases following the above-described deceleration state, if the vehicle is locked up, the engine speed Ne becomes equal to or lower than the idle rotation speed as the vehicle speed decreases, causing an engine stall or shifting in the automatic transmission 30. The gear ratio is increased by step switching, the engine brake is strong, and drivability is deteriorated.
Therefore, when the engine speed decreases to a predetermined engine speed, the automatic transmission control unit 14 sets the lockup signal to the non-engaged side to release the lockup clutch 4 and switches to torque converter transmission that can allow slipping.
[0033]
However, even if the lock-up clutch 4 is released, the engine 1 rapidly decreases in speed due to its own friction if the fuel injection of the engine 1 is stopped. Therefore, in this embodiment, the hybrid system control unit 15 motorizes the engine 1 with the first motor 9 while the clutch 10 is engaged, and maintains the idling speed, for example, so as not to stall.
The C section after the lockup clutch 4 is released is in a motoring deceleration mode.
[0034]
The power required for motoring the engine 1 is only required to be shared by the torque driven from the drive wheel 7 side via the torque converter 3, so the burden on the first motor 9 is small.
In the motoring deceleration mode, the torque converter axle torque is lower than the lockup axle torque in the B section, so the regenerative axle torque of the second motor 8 is increased to obtain the target axle torque.
During this time, the vehicle speed decreases as in the B section.
[0035]
The determination of the regenerative axle torque is the same as in the B section, but there is a difference in that the lockup is released.
Here, the torque converter transmission axle torque is obtained.
The rotational speed ratio before and after the torque converter 3 is known from the engine speed Ne and the vehicle speed V and the selected gear ratio. Then, the input capacity coefficient τ is obtained from the input capacity coefficient map of the torque converter as shown in FIG. 8, and the torque T ′ transmitted by the torque converter can be calculated by the following equation.
T '= τ * Ne * Ne
Then, the torque converter transmission axle torque converted into the axle torque is calculated in consideration of the gear ratio.
[0036]
Assuming that the target axle torque is given as the sum of torque converter transmission axle torque, transmission friction axle torque and regenerative axle torque, the regenerative axle torque is obtained by subtraction, and the second motor 8 is controlled to realize this regenerative axle torque. .
In this way, first, the first motor 9 is controlled at a constant speed so that the engine 1 has a target rotation such as the idling speed, and from the result, the second motor 8 is controlled so as to realize the regenerative axle torque. Overall, engine rotation and regenerative axle torque can be set as target values.
Note that, by setting the engine 1 to the target rotation, vehicle creep torque is generated by the first motor 9 when the vehicle stops.
[0037]
  FIG.Indicates changes in rotational speed and torque when the vehicle is stopped from the deceleration state.
  Until the vehicle stops, the vehicle creep torque is generated by the first motor 9 as described above. However, after the vehicle stops, the reverse driving force from the torque converter 3 side disappears, so that the first motor 9 alone causes engine friction. In order to overcome and drive the engine 1, the power loss of the first motor is large.
  Therefore, when the vehicle is stopped from the deceleration state, a transition mode of the D section is entered, the transmission capacity of the clutch 10 of the first motor 9 is reduced, and the engine speed is reduced due to engine friction. However, the rotation of the first motor 9 is kept constant in order to maintain the function of the auxiliary machine 2 during this period. Instead, the second motor 8 is switched from regeneration to driving, and a creep force is generated by the second motor.
[0038]
As the engine speed decreases, the driving torque of the torque converter 3 decreases. The torque converter transmission axle torque can be calculated by τ * Ne * Ne * t as described above. If the torque converter transmission axle torque and the transmission friction axle torque are subtracted from the target axle torque, the driving axle torque by the target second motor 8 is obtained.
Thus, finally, the clutch 10 is brought into the non-engaged state when the engine rotation becomes zero, and the process proceeds to the idle stop mode of the E section. Here, the first motor 9 only drives the accessory 2, and the creep force is maintained by the second motor 8.
When the engine 1 is stopped, the engine control unit 13 stores the stop position of the engine, that is, the cylinder so that it can be specified which cylinder will be the ignition timing or the fuel injection cylinder at the next start.
[0039]
  FIG.Indicates changes in rotational speed and torque when starting from a vehicle stop state.
  When the accelerator pedal is depressed to accelerate the start, the first motor 9 is used as a starter motor. At that time, if the engine 1 is started and then accelerated, it takes time for cranking to start, and the torque rise slows down. Therefore, a start torque is generated by the second motor 8 and the engine start is delayed. Make up.
[0040]
That is, when the accelerator pedal is depressed in the idle stop mode state of the E section and the accelerator opening is equal to or larger than a predetermined value, the clutch 10 is engaged and the start mode of the F section is started.
The rotational speed of the first motor 9 is controlled so as to maintain the target rotational speed. However, when the rotational speed is decreased by engaging the clutch 10, the maximum torque is output as a result. By engaging the clutch, the first motor 9 and the crankshaft 1a of the engine are connected, and cranking is started.
Note that fuel is supplied from the fuel injection valve to the engine 1 in accordance with the accelerator opening. At this time, based on the cylinder stop position stored when the engine is stopped, fuel is injected from an appropriate cylinder according to the ignition sequence by sequential control.
[0041]
When the rotation of the engine 1 rises due to cranking and the engine completes explosion and starts generating torque, the driving of the first motor 9 is stopped and idling, and the auxiliary machine 2 is driven by engine output. .
The complete explosion of the engine 1 is detected by the hybrid system control unit 15 because, for example, the engine speed has suddenly changed or the driving torque of the first motor 9 is reversed from positive to negative. Can do.
[0042]
  Meanwhile,FIG.The target axle torque corresponding to the accelerator opening is obtained from the map as shown in FIG. 6 and the starting driving force by the second motor 8 is generated to realize the target axle torque. The driving axle torque by the second motor 8 is obtained by subtracting the torque converter transmission axle torque and the transmission friction axle torque from the target axle torque.
  In this way, the start assist by the second motor 8 is performed until the start of the engine 1 is completed, and a quick rise of the drive torque is obtained.
  After the driving axle torque by the second motor 8 becomes zero, the fuel injection mode of the G section in which the target axle torque is covered only by the engine output is set.
[0043]
In the idle stop mode of section E, the oil pressure is supplied to the automatic transmission 30 even when the engine is stopped by the motor-driven automatic transmission oil pump 21, so that the internal clutch 5a can be engaged. The delay is only the cranking time of starting. Therefore, the start assist time by the second motor 8 is shortened, and the vehicle speed range for starting assist can be reduced. Therefore, the second motor 8 having a small output can be selected.
[0044]
Next, the flow of overall control in this embodiment will be described with reference to FIGS. First, a transition end flag and a start mode flag are initially set in steps 101 and 102, and the operation is started under the control of the fuel injection mode.
In step 103, the engine control unit 13 checks the state of the idle switch. If the idle switch is not on, the routine proceeds to step 104 where it is checked whether the start mode flag is set. Here, while the start mode flag is not set, the process returns to step 101 and the above flow is repeated.
[0045]
When the idle switch is turned on in the check at step 103, the routine proceeds to step 105, where the engine control unit 13 stops fuel injection.
In the next step 106, the hybrid system control unit 15 checks the vehicle speed. If the vehicle speed is not zero and the vehicle is traveling, it is determined in step 107 whether the lock-up signal in the automatic transmission control unit 14 is on the engagement side. Check.
Here, when the lock-up signal is on the engagement side, it is determined in step 108 that the lock-up deceleration mode is selected, and the process proceeds to the lock-up deceleration mode control after step 120.
[0046]
When the lockup signal is on the non-engagement side, it is determined in step 109 that the mode is the non-lockup deceleration mode, and then in step 110, it is checked whether the engine speed is lower than the first set value N1. While the engine speed is high, the process returns to step 107 and the same flow is repeated. Then, when the engine speed becomes lower than the first set value, the routine proceeds from step 110 to step 111 to determine the motoring deceleration mode, and the routine proceeds to motoring deceleration mode control after step 130.
[0047]
On the other hand, when the vehicle speed becomes zero in the check in step 106, the hybrid system control unit 15 checks the transition end flag in step 112. When the transition end flag is 0, it is determined in step 113 that the mode is the transition mode, and the process proceeds to transition mode control after step 140.
When the transition end flag is set, it is determined in step 114 that the idle stop mode is set, and the process proceeds to the idle stop mode control after step 160.
[0048]
Further, when the start mode flag is set in the check of step 104, the process proceeds to start mode control after step 170.
[0049]
In the lockup deceleration mode control, first, at step 120, the hybrid system control unit 15 obtains the target axle torque. Here, the target axle torque is read and determined in accordance with the vehicle speed detected by the vehicle speed sensor using the map of the vehicle speed and the target axle torque as shown in FIG.
[0050]
In the next step 121, the engine friction torque with respect to the engine speed is obtained from the engine friction map of FIG. 6, and the engine friction axle torque converted into the axle torque is calculated in consideration of the selected gear ratio.
In step 122, the transmission friction axle torque converted to the axle is obtained from the transmission friction map of FIG. 7 in consideration of the engine speed and the gear ratio.
[0051]
Thereafter, at step 123, the regenerative axle torque is obtained.
Since the target axle torque is given by the sum of the engine friction axle torque, the transmission friction axle torque, and the regenerative axle torque, the regenerative axle torque is obtained by subtracting the engine friction axle torque and the transmission friction axle torque from the target axle torque. At this time, not only the idle switch is turned on, but also when the brake operation is performed and the brake switch is turned on, the regenerative axle torque obtained as described above is further corrected by the vehicle speed. Is preferred.
In step 124, the regenerative axle torque is converted into a regenerative current to control the second motor 8, and then the process returns to step 103.
[0052]
In the motoring deceleration mode control, first, in step 130, the hybrid engine control unit 15 determines the target engine speed, and in step 131, the difference between the actual engine speed and the target engine speed is obtained. In step 132, the difference is multiplied by a predetermined gain to obtain a torque operation amount of the first motor 9, and in step 133, the first motor is feedback-controlled. As a result, the engine 1 is driven and held at a target engine speed, for example, an idling speed.
[0053]
Subsequently, at step 134, as in the previous step 120, the target axle torque is obtained. In step 135, torque converter transmission axle torque is obtained, and in step 136, transmission friction axle torque is obtained.
[0054]
Thereafter, in step 137, the target regenerative axle torque is obtained.
Since the target axle torque is given by the sum of the torque converter transmission axle torque, the transmission friction axle torque, and the regenerative axle torque, the regenerative axle torque is obtained by subtracting the torque converter transmission axle torque and the transmission friction axle torque from the target axle torque.
In step 138, the regenerative axle torque is converted into the regenerative current of the second motor to control the second motor 8, and then the process returns to step 103.
This is repeated and decelerated. When the vehicle speed becomes zero, the transition mode control is performed.
[0055]
In the transition mode control, first, in step 140, the hybrid system control unit 15 sets the target axle torque (creep torque), and in step 141, the transmission capacity of the clutch 10 is controlled by duty control, and the engine by the first motor 9 is controlled. Drop the motoring.
During this time, the rotational speed of the first motor 9 is maintained at the level in the motoring deceleration mode in step 142.
[0056]
In the next step 143, the transmission torque of the torque converter 3 is obtained. In step 144, the torque converter transmission axle torque (torque creep torque) transmitted from the still rotating engine 1 to the drive wheel 7 side through the torque converter 3 is calculated. To do.
In step 145, the target creep torque by the second motor 8 is obtained by subtracting the torque converter creep torque from the target axle torque.
In step 146, the target creep torque is converted into a drive current, and the second motor 8 is controlled.
[0057]
In step 147, it is checked whether the idle switch is on. Here, if the idle switch is turned off, the accelerator pedal has been stepped on, so that the mode shifts to start mode control.
If the idle switch is on, it is checked in next step 148 whether the engine speed has become zero. Until the engine speed reaches 0, the process returns to step 103 and the above is repeated.
When the engine speed becomes 0, the routine proceeds to step 149, the clutch 10 is completely disengaged, and the first motor 9 drives only the auxiliary machine 2 at a constant speed.
Thereafter, a transition end flag is set at step 150 and the process returns to step 103.
[0058]
Next, the control of the transmission capacity of the clutch 10 in step 141 will be described.
Here, the reverse rotation of the crankshaft 1a is prevented particularly when the engine is stopped. That is, FIG. 18 (a) shows the change in the engine speed (rotation speed) over time, but if the clutch 10 is simply disengaged and the decrease in the engine speed is allowed to proceed, the reverse rotation will occur as shown by line B. Cause a phenomenon. This is due to the fact that the crankshaft 1a rotates back to a position exceeding the final stop position and swings back after swinging due to the inertia of each part of the engine.
[0059]
For this reason, as shown in (c), a reference signal (for example, the first cylinder reference signal (1cyl)) should be detected for every four signals, for example, in the case of a four cylinder engine, ( As shown in b), a plurality of reference signals of a certain cylinder are detected, and the reference signal is detected at an unexpected point. Therefore, the stop position of each cylinder cannot be determined.
In this embodiment, therefore, the duty of the clutch 10 is controlled by feedback control, and the engine speed is gradually decreased at a stable inclination as shown by line A in FIG. Yes.
[0060]
FIG. 19 is a flowchart showing a flow of engine speed control by feedback control.
That is, first in step 1410, a predetermined intermediate duty value DT set in advance is set as a control duty value.
Next, in step 1411, the target engine speed Nstp (rotational speed) is obtained by the following equation.
Nstp = Nset−Ddwn
Here, Nset is an engine speed at the start of transition, for example, an idling speed, and Ddwn is a fixed value, indicating that the target engine speed is decreased by Ddwn.
[0061]
Next, at step 1412, a difference dNe between the target engine speed Nstp and the actual engine speed Ne is obtained.
In step 1413, a correction amount Ds corresponding to the difference dNe is obtained from the map of FIG. In this map, a dead zone is set in a region where the difference dNe is (−), but a dead zone is not provided in a region where the dNe is (+), thereby preventing an excessive decrease in engine rotation. .
[0062]
In step 1414, the correction amount Ds is added to the duty value DT to obtain a new control duty value DT. As a basic tendency, the control duty value DT decreases toward zero.
Thereafter, in step 1415, Nset = Nstp is set, and the flow returns to step 1411 to repeat the above flow until the engine speed becomes zero.
Thus, since the target engine speed Nstp at the time of map transition gradually decreases toward 0, reverse rotation due to the engine overshooting at the moment of stop is suppressed.
The above steps 1410 to 1415 constitute the engine speed control means of the invention.
[0063]
Returning to the overall flow, in the idle stop mode control, in step 160, the hybrid motor control unit 15 holds the first motor 9 at the target rotational speed, and in step 161, the target axle torque (creep torque) is maintained. Thus, the second motor 8 is controlled.
In step 162, it is checked whether the idle switch is on. Here, if the idle switch is turned off, the accelerator pedal has been stepped on, so that the mode shifts to start mode control.
[0064]
If the idle switch is on, it is checked in step 163 whether the vehicle speed is zero. Even if the accelerator pedal is not depressed, if creeping is allowed and the vehicle is advanced, the control proceeds to start mode control as above.
If the vehicle speed is zero in the check in step 163, the process returns to step 160 and the above is repeated, and the idle stop mode control is continued.
[0065]
In the start mode control, in step 170, the hybrid system control unit 15 first sets a start mode flag.
Next, at step 171, the clutch 10 is engaged, and at step 172, the rotational speed control is performed so as to maintain the rotational speed of the first motor 9 so far. Thereby, the cranking of the engine 1 is performed by the rotation output of the first motor 9. As a control result of maintaining the rotational speed, the output torque of the first motor 9 increases during cranking.
[0066]
In step 173, the target axle torque is obtained based on the map of FIG. 11, and in step 174, the target torque of the second motor 8 is obtained from the difference between the target axle torque and the torque converter transmission axle torque.
In step 175, the second motor 8 is controlled by converting the target torque into a drive current.
Meanwhile, in step 176, the engine control unit 13 performs engine start control such as fuel injection and ignition timing.
[0067]
In step 177, it is checked whether or not the engine 1 has been completely exploded.
When the engine 1 is completely detonated, the routine proceeds to step 178 where the driving of the first motor 9 is stopped and its output torque is set to zero.
After the complete explosion, the driving of the second motor 8 ends when the torque converter transmission axle torque by the engine output reaches the target axle torque.
Thereafter, in step 179, the start mode flag is set to 0, and the process returns to step 103.
[0068]
The present embodiment is configured as described above. The auxiliary motor 2 can be driven independently of the engine 1 and the clutch 10 can be connected to the crankshaft 1a of the engine, the torque converter 3 and the drive wheels 7. And a second motor 8 connected between the two motors. The second motor 8 regenerates at the time of deceleration and the engine 1 is motored by the first motor 9 to prevent engine stall until the vehicle stops. Since the creeping force is applied to the vehicle by the second motor 8 while the auxiliary machine is driven by 9, the fuel injection during stopping at the deceleration and the intersection can be stopped to obtain a significant fuel saving.
[0069]
Further, since the cranking is performed by the first motor 9 at the time of starting, the starter motor can also be used.
Furthermore, the auxiliary machine 2 is driven even when the vehicle is stopped, and the second motor 8 is driven and assisted at the time of starting and starting, so that the rising at the time of restarting is remarkably quick.
[0070]
In particular, when the engine rotation is shifted from the motoring to the engine rotation stop, the clutch 10 between the first motor 9 and the crankshaft 1a is duty-controlled to gradually reduce the fastening force and prevent the engine 1 from rotating in reverse. The location is clearly identified. As a result, all cylinder injections of fuel are not required at the time of re-starting, and optimal sequential injection can be performed from the beginning. Thus, good startability can be obtained and further fuel saving can be achieved.
[0071]
In the embodiment, a clutch for connecting the engine crankshaft and the first motor is attached to the first motor. However, the first motor is always connected to the auxiliary machine and can be selectively connected to the crankshaft. For example, the installation site of the clutch is not particularly limited. For example, the clutch can be attached to the auxiliary machine side so that the first motor and the crankshaft can be connected via the auxiliary machine.
[0072]
In the above embodiment, the target engine speed Nstp is obtained by calculation of (Nstp = Nset−Ddwn) for each repetition of the flow when the engine rotation is stopped in the transition mode control. It can also be determined by reading from.
That is, FIG. 21 is a flowchart showing another example of target engine speed setting in engine speed control by feedback control.
First, in step 1420, a predetermined intermediate duty value DT set in advance is set as a control duty value.
[0073]
Next, in step 1421, it is checked whether it is the first flow that has entered the transition mode. If it is the first time, the process proceeds to step 1422, the counter Cstp is set to 0, and after the second time, the counter Cstp is incremented in step 1423.
Thereafter, the process proceeds to step 1424, and a target engine speed Nstp (rotation speed) corresponding to the value of the counter Cstp is obtained from the transition target engine speed map as shown in FIG.
In this map, the target engine speed Nstp is set to linearly decrease from the engine speed at the start of the transition, for example, the idling speed, and gradually settles to 0 at the final stage as the counter value advances. .
[0074]
The subsequent steps 1425 to 1428 are the same as steps 1412 to 1415 in FIG. 19, and the flow returns from step 1428 to step 1421 to repeat the above flow until the engine speed becomes zero.
Since the target engine speed is prepared as a map, an arbitrary change tendency can be set, and this can also be stopped gently.
[0075]
【The invention's effect】
  As described above, the present invention is provided with the first motor that can be connected to the engine crankshaft by the clutch.In addition to controlling the engine and the transmission, and having a control device having an engine speed control means, firstly, the fuel supply to the engine is stopped during vehicle deceleration, so that fuel consumption during deceleration is reduced. Have an effect.
[0076]
  AndThe engine speed control meansWhen the engine stopsSuppresses engine reverse rotation by controlling clutch transmission capacityIn this way, the engine speed is controlled so that the stop position of the engine cylinder can be specified without error, and a good startability can be obtained when restarting..
[0077]
In addition, the first motor is always connected to the engine accessory, and the engine is motored by the first motor during vehicle deceleration, and the engine rotation state is maintained until the vehicle stops, so that But it can be re-accelerated without restarting the engine.
In this case, in the control by the engine speed control means, the engine speed is gradually reduced from the motoring speed, so that the speed changes smoothly from the motoring state, so there is no shock to the passenger.
In particular, it is easy to reduce the transmission capacity of the clutch by duty control, and control with high accuracy can be obtained.
[0078]
In addition, by providing the second motor, the vehicle deceleration energy can be regenerated to obtain an appropriate deceleration feeling and the energy can be stored, while the second motor is driven based on the energy while the engine is stopped to creep. Can give power.
[0079]
Furthermore, when the vehicle restarts, the second motor adds a driving force that is greater than the creep force that is stopped, so that the start of the vehicle can be started quickly.
In addition, the starter motor can also be used by cranking with the first motor when starting.
[Brief description of the drawings]
FIG. 1 is a skeleton diagram showing a power train in an embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a hydraulic pressure supply source for an automatic transmission.
FIG. 3 is a diagram illustrating a configuration of a control device in a power train.
FIG. 4 is a time chart in the case of decelerating from a constant speed running state.
FIG. 5 is a diagram showing a map for obtaining a target axle torque during deceleration.
FIG. 6 is a diagram showing an engine friction map.
FIG. 7 is a diagram showing a transmission friction map.
FIG. 8 is a diagram showing an input capacity coefficient map of a torque converter.
FIG. 9 is a time chart when the vehicle is stopped from the deceleration state.
FIG. 10 is a time chart when starting from a vehicle stop state.
FIG. 11 is a diagram showing a map for obtaining a target axle torque at the time of start.
FIG. 12 is a flowchart showing a flow of overall control in the embodiment.
FIG. 13 is a flowchart showing a flow of overall control in the embodiment.
FIG. 14 is a flowchart showing a flow of overall control in the embodiment.
FIG. 15 is a flowchart showing a flow of overall control in the embodiment.
FIG. 16 is a flowchart showing a flow of overall control in the embodiment.
FIG. 17 is a flowchart showing a flow of overall control in the embodiment.
FIG. 18 is a diagram showing changes in engine speed when the engine is stopped.
FIG. 19 is a flowchart showing a flow of engine speed control.
FIG. 20 is a diagram illustrating a correction amount map in duty control.
FIG. 21 is a flowchart showing a flow of engine speed control.
FIG. 22 is a diagram showing a target engine speed map at the time of engine stop transition.
FIG. 23 is a diagram illustrating a conventional example.
[Explanation of symbols]
1 engine
1a Crankshaft
1b Crank pulley
2 Auxiliary machines
2a belt
3 Torque converter
4 Lock-up clutch
5. Transmission mechanism
5a Internal clutch
6 Deceleration and differential unit
7 Drive wheels
7a, 7b Drive shaft
8 Second motor
9 First motor
9a belt
10 Clutch
12 Hydraulic control unit
13 Engine control unit
14 Automatic transmission control unit
15 Hybrid system control unit
20, 21 Oil pump
22 Check valve
30 Automatic transmission
Ne engine speed
Nstp target engine speed

Claims (7)

The engine transmits its crankshaft output to the drive wheels via the transmission, speed reducer, axle, and is used as a power source for vehicle travel.
A first motor is attached to the crankshaft so as to be connectable by a clutch,
A control device that controls the engine and the transmission and includes engine speed control means,
The control device stops fuel supply to the engine during vehicle deceleration,
The engine speed control means controls a reduction state of the engine speed so as to suppress reverse rotation of the engine by controlling the transmission capacity of the clutch when the engine rotation is stopped . The first motor is always connected to an engine accessory, and the control device is configured to motor the engine by the first motor during vehicle deceleration and maintain the engine rotation state until the vehicle stops. the vehicle powertrain system of claim 1, wherein the are. 3. The vehicle power train system according to claim 2, wherein the engine speed control means gradually decreases the engine speed from the motor speed . 4. The vehicle power train system according to claim 3, wherein the engine speed control means is configured to duty-control the clutch and gradually reduce the transmission capacity . A second motor is connected to the rear stage of the transmission, and the control device is configured to regenerate vehicle deceleration energy by the second motor during vehicle deceleration and to apply a creep force by the second motor while the vehicle is stopped. and powertrain system for a vehicle as claimed in any one of the 4, characterized in that are. The fuel supply of the engine is performed by fuel injection,
When the vehicle restarts, the clutch is engaged and the crankshaft is cranked by the first motor and started.
6. The vehicle power train system according to claim 1, wherein the fuel supply at the time of start-up is performed by sequential injection based on the stop position of the engine . The vehicle power train system according to claim 6, wherein a driving force larger than the creep force is applied by the second motor when the vehicle restarts .

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