JP5169430B2 - Oil pump control system for hybrid vehicles - Google Patents

Description

  The present invention relates to a technique applied to a hybrid vehicle in which an electric motor (simple motor) and an electric motor (motor generator) having a power generation function are mounted together with an engine (internal combustion engine) as a drive source. More specifically, the present invention relates to a control system for efficiently operating an oil pump that supplies hydraulic pressure when the hybrid vehicle includes a plurality of fastening elements driven by hydraulic pressure. In the present specification, for simplicity of explanation, a simple motor and a motor having a power generation function are also referred to as a motor generator.

  In recent years, a hybrid vehicle having a plurality of drive sources has attracted attention from the viewpoint of environmental protection. A type of hybrid vehicle in which an engine and a motor generator (MG) are mounted as drive sources is well known. This type of hybrid vehicle is an EV mode (electrical mode) that travels only with the power of the motor generator, when the motor generator is used as the engine power during acceleration with the engine as the main power, or when the motor generator travels while generating power. Is set to HEV mode (hybrid mode), and the above mode is switched appropriately. The hybrid vehicle achieves improved fuel efficiency by switching between modes.

  In the powertrain system of a hybrid vehicle, a plurality of fastening elements such as clutches and brakes driven by hydraulic pressure are provided. Therefore, since an oil pump that supplies oil to each fastening element is mounted, it is necessary to control these efficiently. In view of this, a mechanical oil pump that is operated in accordance with the driving of the engine or motor generator is provided, and working hydraulic pressure is secured to a fastening element (such as a coupling clutch arranged on the drive shaft or a clutch or brake in an automatic transmission). There was a thing.

  However, the hybrid vehicle may be set to automatically stop the engine in order to improve fuel efficiency. For this reason, for example, when the engine is stopped when the vehicle is stopped, such as waiting for a signal, the oil pump is stopped accordingly, so that it may be difficult to supply the necessary hydraulic pressure to each fastening element.

  Therefore, an auxiliary oil pump (sub oil pump) that is externally driven by electric power, separately from the oil pump (main oil pump) that operates in conjunction with the engine drive, so that the hydraulic pressure to the fastening element can be secured when the engine is stopped. ) Has been proposed.

As described above, for example, there is an engine stop / start control device disclosed in Patent Document 1 regarding a hybrid vehicle including a main oil pump and a sub oil pump in an operating hydraulic system. This control device maintains the hydraulic pressure of the transmission at a predetermined hydraulic pressure required for torque transmission by operating the electric sub oil pump while the engine is stopped.
JP 2004-68732 A

  However, in the engine stop / start control device according to Patent Document 1, the sub oil pump is steadily operated during idle stop of the engine, and is appropriately operated when the hydraulic pressure from the main oil pump is insufficient. The operation frequency increases and power consumption increases. In this case, there is a concern about deterioration of fuel consumption in a hybrid vehicle that improves fuel consumption.

  Therefore, an object of the present invention is an oil pump control of a hybrid vehicle in which a main oil pump and a sub oil pump are provided, and the operation time of the sub oil pump can be reliably shortened to improve fuel efficiency. Is to provide a system.

In order to achieve the above object , an oil pump control system for a hybrid vehicle of the present invention has an engine and a motor generator as drive sources, a plurality of fastening elements arranged along the drive shaft and driven by hydraulic pressure, and these fastenings And an oil pump control system applied to a hybrid vehicle provided with a main oil pump that responds to the drive source and a sub oil pump that operates with external force as the oil pump. There,
At least one of the fastening elements is a normally closed type fastening element that is in a fastening state by a spring force of a diaphragm spring when no hydraulic pressure is applied, and is in an open state when the hydraulic pressure is applied. And a piston that transmits hydraulic pressure to the fastening member, and an oil storage section that moves the piston and changes the oil storage volume in accordance with the state of the oil supplied from the oil pump. Formed with a containment structure,
Furthermore, a position detection sensor for detecting the movement position of the piston;
When it is confirmed that the piston is in the maximum open position based on the output of the position detection sensor, the operation of the sub oil pump is stopped, and the piston is moved to the fastening position based on the output of the position detection sensor. It is characterized by having a pump control means for operating the sub oil pump when it is confirmed that it is in the close fastening start position (actual opening position) .

  In the oil pump control system of the present invention, the pump control means detects the piston moving position when supplying oil to the fastening element having the oil containing structure having the oil containing portion that changes the oil containing volume by the movement of the piston. Since the sub oil pump is driven based on the output of the position detection sensor, the operation time can be shortened. Thereby, the fuel consumption improvement of a hybrid vehicle can be aimed at.

  Hereinafter, a hybrid vehicle to which an oil pump control system according to an embodiment of the present invention is applied will be described in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of a power train system included in a hybrid vehicle CR. First, the power train system will be described, and then a hydraulic control system applied thereto will be described.
In the hybrid vehicle CR, an engine E, a first clutch CL1, a motor generator MG, a second clutch CL2, an automatic transmission AT, a propeller shaft PS, and a differential DF are arranged in series in this order. A left drive shaft DSL and a right drive shaft DSR extend from the differential DF, and a left rear wheel RL (drive wheel) and a right rear wheel RR (drive wheel) are connected to each.

  The engine E can be, for example, a gasoline engine or a diesel engine. The hybrid vehicle CR is provided with a controller CONT that controls the entire vehicle. Various information indicating the vehicle state (for example, throttle valve opening, engine speed, vehicle speed, shift information, etc.) is input to the controller CONT, and the controller CONT is set to control the entire hybrid vehicle based on these information. Has been. Such a controller may be provided for each of the engine E, the motor generator MG, and the automatic transmission AT, and an integrated controller that performs integrated control of these may be provided. However, in the present embodiment, the description will be made assuming that the controller CONT performs the overall control including the operation of the hybrid vehicle CR, particularly the drive control of the oil pump related to the hydraulic system to be described later.

  The motor generator MG is a synchronous motor generator in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator, for example, and is controlled based on a control command from a controller CONT. This motor generator MG operates as an electric motor that rotates by receiving electric power supplied from the battery BAT, and functions as a generator that generates electromotive force at both ends of the stator coil when the rotor is rotated by an external force. Then, the battery BAT can be charged. The rotor of motor generator MG is connected to the input shaft of automatic transmission AT via a damper (not shown).

  The first clutch CL1 is interposed between the engine E and the motor generator MG, and is formed as, for example, a hydraulic single-plate clutch or a hydraulic multi-plate clutch. The first clutch CL1 is formed into an engagement state, an actual release state, and a maximum release state by a control oil pressure generated by an oil pump described later based on a control command from the controller CONT.

  The second clutch CL2 is interposed between the motor generator MG and the left and right rear wheels RL, RR, and is, for example, a hydraulic multi-plate clutch. The second clutch CL2 is also engaged and disengaged by a control oil pressure generated by an oil pump described later based on a control command from the controller CONT.

  The automatic transmission AT is an automatic transmission that is automatically switched according to the vehicle speed, the accelerator opening, and the like. Here, the second clutch CL2 may be added as a dedicated clutch. However, the second clutch CL2 is not limited to this, and among the plurality of frictional engagement elements provided as the shift elements of the automatic transmission AT, the power transmission of each shift stage is performed. A frictional engagement element existing in the path may be used. The output shaft of the automatic transmission AT is connected to the left and right rear wheels RL and RR via a propeller shaft PS, a differential DF, a left drive shaft DSL, and a right drive shaft DSR.

  The hybrid vehicle is equipped with two oil pumps. The first is a mechanical mechanical oil pump (hereinafter referred to as main oil pump) M-O / P, which is disposed between the motor generator MG and the second clutch CL2. The main oil pump M-O / P can be deployed as an internal gear pump, an external gear pump, a vane pump, or the like that generates discharge pressure using at least one of the engine E and the motor generator MG as a power source. The main oil pump M-O / P shown in FIG. 1 is configured to generate hydraulic pressure in response to the rotation of the rotation shaft of the motor generator MG, that is, the transmission input shaft.

The second is an external and electric auxiliary oil pump (hereinafter referred to as a sub oil pump) S-O / P, whose drive is controlled by a control command from the controller CONT. As such a sub oil pump S-O / P, a known electric pump can be appropriately employed.
In FIG. 1, the hydraulic circuit of the main oil pump MO / P and the sub oil pump SO / P is simplified, but the main oil pump MO / P secures the required hydraulic pressure. It is designed to operate the sub oil pump S-O / P when it cannot.

  FIG. 2 is a diagram showing a configuration example that can be adopted as a hydraulic circuit that connects the main oil pump M-O / P and the sub-oil pump S-O / P. For example, oil (oil) stored in the oil pan 10 below the automatic transmission AT is sucked by the main oil pump M-O / P through the passage 11. Similarly, it is sucked by the sub oil pump S-O / P through the passage 12. A switching valve mechanism 13 is provided at the other end of both passages 11 and 12. Inside the switching valve mechanism section 13, flapper valves 14 and 15 are provided at positions corresponding to the passages 11 and 12, respectively, and are biased with a predetermined pressure from the spring material toward the closing side. Therefore, oil of a predetermined pressure or more entering the switching valve mechanism 13 can be supplied to the first clutch CL1 and the second clutch CL2 via the hydraulic circuit 16. The hydraulic circuit 16 shown here may be shared with the hydraulic circuit of the automatic transmission AT.

Furthermore, with reference to a figure, the structure with which 1st clutch CL1 which is one of the fastening elements is provided is demonstrated. FIG. 3 is a view for explaining an oil storage structure provided in the first clutch CL1. The first clutch CL1 is in a state of oil supplied from the above-described oil pumps (MO / P, S / O / P) and a piston that is movable between the engagement position and the maximum release position and changes its position. An oil containing structure including an oil containing portion that changes the oil containing volume by moving the piston according to the oil pressure and the oil amount).
Note that FIG. 3 is a diagram schematically showing a state in which the first clutch CL1 is engaged above the center line and a maximum opening state is below the center line. The first clutch CL1 is a normally closed type that is designed to form the engaged state (closed state) shown in the upper stage when no hydraulic pressure is supplied.

  In FIG. 3, the left side is the engine side, the left end of the first clutch CL1 is the flywheel FW, and the disk DS and the pressure plate PL are disposed in the housing HW. This pressure plate PL is pressed by a diaphragm spring DP.

And the above-mentioned oil storage structure is provided on the right side of the diaphragm spring DP. Here, this structure is referred to as a CSC (Concentrated Spool Cylinder) structure. The CSC structure is formed as a structure in which a donut-shaped piston PT moves in the axial direction in an annular oil storage chamber RM formed by being surrounded by inner and outer walls. Here, since the oil storage volume of the oil storage chamber RM changes depending on the position of the piston PT, the oil storage chamber RM becomes the oil storage portion.
As described above, the first clutch CL1 is a normally closed type, and the piston PT protrudes to the left side as the oil storage volume in the oil storage portion increases, and most protrudes when it is fully opened against the pressing force of the diaphragm spring DP. The state shown in the lower part is formed. When the supply of oil is stopped, the oil pressure acting on the piston PT decreases with time due to oil leakage, etc., so the piston PT gradually retracts due to the action of the diaphragm spring DP, and passes through the actual open position immediately before the fastening force is generated It will approach the fastening state shown in the upper row.

  At the time of fastening shown in the upper part of FIG. 3, the piston PT is located on the rightmost side and is most buried in the oil storage chamber RM (fastening position of the piston PT). On the contrary, at the time of maximum opening shown in the lower stage, the piston PT is located on the leftmost side and protrudes most from the oil storage chamber RM (opening position of the piston PT). Here, if the volume relationship between the volume of the oil storage chamber RM and the piston PT moving inside the oil storage chamber RM is appropriately set, the operating oil pressure accumulated in the oil storage chamber RM is utilized to make use of the sub oil pump S−. The operation time of O / P can be shortened. That is, the sub oil pump S-O / P can be stopped while the piston PT is moved by the operating pressure of the oil accumulated in the oil storage chamber RM.

  More specifically, as shown in FIG. 3, the oil storage chamber of the CSC structure is connected to the hydraulic circuit 16 of FIG. 2, and is supplied from an oil pump (MO / P, S / O / P). The pressurized oil is supplied to the oil storage chamber. Here, as shown in the lower stage, when the valve is fully opened, a predetermined amount of oil is stored (accumulated) in the oil storage chamber RM. Thereafter, when the hydraulic pressure supply is stopped, the action due to the hydraulic pressure is gradually reduced, and the piston PT gradually moves toward the fastening state shown on the upper side. During this time, since the piston PT maintains the hydraulic pressure in the hydraulic circuit 16, there is no need to operate the sub oil pump S-O / P, so the operating time of the sub oil pump is shortened by utilizing the CSC structure. it can. As a result, the fuel efficiency of the vehicle can be improved. The basic concept of the present invention is to utilize the oil storage structure provided in the first clutch CL1 (engagement element) like an accumulator as described above to ensure the downtime of the sub oil pump.

  As shown in FIG. 3, in this embodiment, a stroke sensor 20 for detecting the movement amount (stroke) is arranged in the vicinity of the piston PS in order to ensure the operation stop (pause) time of the sub oil pump. It is set up. The output signal of the stroke sensor 20 is also supplied to the controller CONT described above.

  As shown in FIG. 3, a hydraulic pressure holding solenoid SOL (pressure holding SOL) is arranged in the middle of the oil passage TB from the hydraulic circuit 16 to the oil storage chamber RM as an actuator that opens and closes the oil passage TB when necessary. It is desirable to keep it. If such an oil pressure holding solenoid SOL is arranged so that the oil passage can be appropriately cut off, leakage of the oil pressure supplied to the clutch CL1 can be prevented, so that the operation stop time of the sub oil pump can be more reliably extended. . As a result, the power consumption can be further reduced.

  FIG. 4 is a time chart summarizing the relationship between the release and engagement of the first clutch CL1 and the ON (ON) and OFF (OFF) operations of the sub oil pump S-O / P. As indicated by the arrow AR, it is possible to secure a time for stopping the sub oil pump S-O / P for a certain time during which the piston moves from the maximum open position to the fastening start position (actual open position).

  FIG. 5 is a flowchart showing an example of a control routine executed by the controller CONT serving as a pump control means, and relates to a structure having the holding solenoid SOL shown in FIG. FIG. 6 is a time chart summarizing the relationship between the opening and closing of the clutch CL1 and the ON (ON) and OFF (OFF) operations of the sub oil pump S-O / P.

  The routine shown in the flowchart of FIG. 5 is started by the controller CONT when, for example, the ignition (IG) of the hybrid vehicle is turned on (ON), EV permission determination (step S101), and sub (Sub) oil pump operation permission. It is confirmed that both determinations (step S102) are yes, and the sub oil pump is ready for operation.

  The controller CONT operates the sub oil pump when necessary in accordance with the state of the main oil pump, and maintains the hydraulic pressure holding solenoid SOL in the OFF state (step S104). Further, it is confirmed from the output of the stroke sensor 20 whether or not the clutch CL1 is at the maximum release position (step S105).

  When it is determined in step S105 that the clutch CL1 is at the maximum disengaged position, the controller CONT stops the sub oil pump and turns on the hydraulic pressure holding solenoid SOL to shut off the oil passage TB, thereby preventing the hydraulic leak. Prevention is performed (step S106). Thereafter, the controller CONT monitors whether the clutch CL1 has reached the engagement start position from the output of the stroke sensor 20 (step S107). Therefore, the sub oil pump can be stopped at the time between step S106 and step S107 by the routine shown in FIG. In other words, the operating time of the sub oil pump can be shortened to improve fuel efficiency.

In the example described in FIG. 5, the hydraulic pressure holding solenoid SOL that blocks the oil passage TB is provided, so that the hydraulic oil can be prevented from leaking and the operation time of the sub oil pump can be shortened reliably. It can be confirmed in FIG. 6 that the holding time of the sub oil pump can be lengthened by providing the holding solenoid SOL.
If the operation related to the solenoid SOL shown in parentheses in steps S104 and S106 in the flowchart shown in FIG. 5 is deleted, a routine related to the oil pump control system not including the solenoid SOL can be obtained.

  In addition, with respect to the position detected by the stroke sensor 20 that detects the movement position of the piston PS in FIG. 3, the detection position of the maximum opening position of the piston is changed from the standard position to the back so that the oil volume change of the oil storage portion increases. The operation time of the sub oil pump may be further shortened by extending the time until fastening by a simple change in which the offset is set to the side.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.
If the line pressure is reduced when the regulator valve provided in the hydraulic circuit is closed, the position when the line pressure is reduced is offset from the conventional drain position, and the same as when the holding solenoid SOL is provided. The hydraulic pressure holding action may be obtained.

  As described above, according to the oil pump control system of the present invention, when oil is supplied to the fastening element having the oil containing structure having the oil containing portion that changes the oil containing volume by the movement of the piston, the pump control means Since the sub oil pump is driven based on the output of the position detection sensor for detecting the piston movement position, the operation time can be shortened. Thereby, the fuel consumption improvement of a hybrid vehicle can be aimed at.

  It is desirable that an actuator for opening and closing an oil passage for supplying oil to the oil storage portion is further provided.

  Further, the detection position of the maximum opening position by the position detection sensor may be set offset from the standard position to the back side so that the oil volume change of the oil storage portion increases.

1 is a system diagram showing a hybrid vehicle to which an oil pump control system of an embodiment is applied. It is the figure which showed the structural example employable as a hydraulic circuit which connects a main oil pump and a sub oil pump. It is the figure shown in order to demonstrate the oil storage structure with which a 1st clutch is provided. 6 is a time chart summarizing the relationship between the release and engagement of the first clutch and the ON / OFF operation of the sub oil pump. It is the flowchart which showed an example of the control routine performed by a controller. 6 is a time chart summarizing the relationship between the release and engagement of the first clutch and the ON and OFF operations of the sub oil pump, corresponding to the flowchart shown in FIG.

Explanation of symbols

E Engine MG Motor generator CL1 First clutch (engagement element)
CL2 Second clutch (engagement element)
M-O / P Main oil pump S-O / P Sub-oil pump 20 Stroke sensor (position detection sensor)
PS Piston RM Oil storage chamber CONT controller (pump control means)
CR hybrid vehicle

Claims (2)

A drive source having an engine and a motor generator, a plurality of fastening elements arranged along the drive shaft and driven by hydraulic pressure, and an oil pump for supplying oil to the fastening elements, and the drive source as the oil pump An oil pump control system applied to a hybrid vehicle in which a main oil pump that operates in response to a sub-oil pump that operates with external force is provided,
At least one of the fastening elements is a normally closed type fastening element that is in a fastening state by a spring force of a diaphragm spring when no hydraulic pressure is applied, and is in an open state when the hydraulic pressure is applied. And a piston that transmits hydraulic pressure to the fastening member, and an oil storage section that moves the piston and changes the oil storage volume in accordance with the state of the oil supplied from the oil pump. Formed with a containment structure,
Furthermore, a position detection sensor for detecting the movement position of the piston;
When it is confirmed that the piston is in the maximum open position based on the output of the position detection sensor, the operation of the sub oil pump is stopped, and the piston is moved to the fastening position based on the output of the position detection sensor. An oil pump control system for a hybrid vehicle, comprising: pump control means for operating the sub oil pump when it is confirmed that the fastening start position (actual release position) is approaching.   2. The oil pump control system for a hybrid vehicle according to claim 1, further comprising an actuator for opening and closing an oil passage for supplying oil to the oil storage section.

Images