JP7575287B2 - Oil pump discharge volume switching device - Google Patents

Description

The present invention relates to an oil pump discharge rate switching device.

Automatic transmissions for vehicles (for example, stepped automatic transmissions (Step ATs) and continuously variable transmissions (CVTs)) are equipped with an oil pump that is driven by engine power and discharges high-pressure hydraulic oil, and various functions such as gear shifting and forward/reverse switching are realized by regulating and supplying the high-pressure hydraulic oil discharged from this oil pump.

On the other hand, in recent years, there has been a demand to reduce the load on oil pumps in response to demands for improved fuel efficiency in vehicles. For example, Patent Document 1 discloses a technology for reducing the load on such oil pumps, which switches a variable displacement pump that draws in oil from two suction ports and discharges it from two discharge ports between a full capacity operating state in which the two discharge ports are completely blocked from the two suction ports, and a half capacity (partial capacity) operating state in which one of the two discharge ports is connected to one of the suction ports (operating state switching device for a variable displacement pump).

More specifically, the variable displacement pump operating state switching device described in Patent Document 1 includes an electronic control unit that switches the operating state of the oil pump between a full capacity operating state and a half capacity operating state, and this electronic control unit includes a half capacity operating state discharge flow rate calculation means, a required discharge flow rate calculation means, and an operating state switching means. The half capacity operating state discharge flow rate calculation means calculates the oil discharge flow rate when the oil pump is in the half capacity operating state based on the engine speed detected by the engine speed sensor and the transmission oil temperature detected by the transmission oil temperature sensor. The required discharge flow rate calculation means calculates the currently required discharge flow rate of the oil pump based on the vehicle specifications and the operating state of the vehicle. Here, the required discharge flow rate is composed of a flow rate required to change the side pressure of the drive pulley and driven pulley of the transmission to perform gear shifting, a flow rate equivalent to the amount of oil leaking from the hydraulic circuit of the transmission, and a flow rate required to lubricate the lubricated parts of the transmission.

The operating state switching means calculates the marginal flow rate by subtracting the required discharge flow rate of the oil pump calculated by the required discharge flow rate calculation means from the discharge flow rate when the oil pump is in the half-capacity operating state calculated by the half-capacity operating state discharge flow rate calculation means, and if the marginal flow rate is equal to or greater than a preset threshold, controls the shift solenoid valve to control the operating state of the oil pump to the half-capacity operating state, and if it is less than the threshold, controls the oil pump to the full-capacity operating state.

According to this variable displacement pump operating state switching device, when the difference (margin flow rate) between the oil pump discharge flow rate calculated by the half-capacity operating state discharge flow rate calculation means and the required oil pump discharge flow rate calculated by the required discharge flow rate calculation means is equal to or greater than a predetermined judgment threshold, the operating state switching means switches the variable displacement oil pump to a half-capacity operating state, thereby making it possible to save on the driving energy of the variable displacement oil pump while ensuring the minimum required discharge flow rate.

International Publication No. 2013/069101

As described above, in the variable displacement pump operating state switching device described in Patent Document 1, when the difference (margin flow) between the oil pump discharge flow rate when in a half-capacity operating state calculated based on the engine speed and transmission oil temperature and the required oil pump discharge flow rate calculated from the vehicle specifications and the vehicle operating state is equal to or greater than a predetermined judgment threshold, the shift solenoid valve is controlled to switch the oil pump operating state to a half-capacity operating state, and when it is less than the judgment threshold, the oil pump is switched to a full-capacity operating state.

Here, the electronic control unit usually controls the switching between the full capacity operating state (full discharge state) and the half capacity operating state (half discharge state) with a margin on the safe side, taking into consideration, for example, manufacturing variations (individual variations) of the oil pump, pump shift valve, shift solenoid valve, and each sensor (characteristic), deterioration over time, etc. (i.e., assuming the worst case). In other words, when calculating the discharge flow rate of the oil pump in the half capacity operating state, the required discharge flow rate of the oil pump, and setting a predetermined judgment threshold value to be compared with the marginal flow rate, it is necessary to perform processing with a margin on the safe side. Therefore, in the variable displacement pump operating state switching device described in Patent Document 1, the half discharge (partial discharge) operating range is limited, and there is a risk that the load reduction effect of the oil pump cannot be fully obtained.

The present invention has been made to solve the above problems, and aims to provide an oil pump discharge rate switching device that can expand the operating range of the partial discharge (half discharge) state, further reducing the load on the oil pump and further reducing the fuel consumption rate (fuel economy).

The oil pump discharge amount switching device of one embodiment of the present invention comprises an oil pump having a first discharge port and a second discharge port for discharging pressurized oil, a discharge state switching means for switching the discharge state of the oil pump to a full discharge state in which the first discharge port and the second discharge port are connected to a high-pressure oil passage, or a partial discharge state in which the first discharge port is connected to a high-pressure oil passage and the second discharge port is connected to an intake port of the oil pump, based on a predetermined discharge state switching condition, a target oil pressure setting means for setting a learning target oil pressure higher than the target oil pressure during normal control in order to learn the saturated oil pressure of the high-pressure oil passage that is correlated with the amount of oil leaking from the hydraulic circuit when the predetermined learning condition is satisfied, and a learning target oil pressure setting means for setting the oil pressure of the high-pressure oil passage to a learning target oil pressure higher than the target oil pressure during normal control when the predetermined learning condition is satisfied. The device is equipped with a pressure regulating means for performing pressure regulation control so that the pressure in the high-pressure oil passage matches the learning target pressure, a learning means for learning the saturated oil pressure and engine speed when the oil pressure in the high-pressure oil passage is saturated while the pressure regulating means is performing pressure regulation control so that the oil pressure in the high-pressure oil passage matches the learning target oil pressure, and a correction value acquisition means for acquiring a correction value for correcting the discharge state switching condition based on a comparison between the saturated oil pressure and the learning target oil pressure at the engine speed learned by the learning means, and the discharge state switching means corrects the discharge state switching condition using the correction value acquired by the correction value acquisition means during normal control other than learning, and switches between the full discharge state and the partial discharge state based on the corrected discharge state switching condition.

According to the present invention, the operating range of the partial discharge (half discharge) state can be expanded, which can further reduce the load on the oil pump and further reduce the fuel consumption rate (fuel economy).

1 is a diagram showing a configuration of a discharge amount switching device for an oil pump according to an embodiment; 1 is a diagram showing a configuration of a continuously variable transmission to which a discharge amount switching device for an oil pump according to an embodiment is applied; 5 is a diagram for explaining learning control by the discharge amount switching device of the oil pump according to the embodiment. FIG. FIG. 4 is a diagram illustrating an example of a correction coefficient map. 13A and 13B are diagrams showing an example of a half-discharge switching permission table (before and after correction); 1 is a diagram for explaining an expansion of an operating range in a partial discharge (half discharge) state by a discharge amount switching device of an oil pump according to an embodiment. FIG. 4 is a flowchart showing a processing procedure of a learning process and a discharge rate (discharge state) switching process performed by the discharge rate switching device of the oil pump according to the embodiment;

Below, a preferred embodiment of the present invention will be described in detail with reference to the drawings. Note that in the drawings, the same reference numerals will be used for the same or corresponding parts. In addition, in each drawing, the same elements will be given the same reference numerals, and duplicate explanations will be omitted.

First, the configuration of the oil pump discharge rate switching device 1 according to the first embodiment will be described with reference to both Figures 1 and 2. The oil pump discharge rate switching device 1 switches and controls the flow rate of oil discharged from an oil pump 10 used in an automatic transmission or the like. Note that the present invention will be described here as an example in which it is applied to a continuously variable transmission (CVT) 110. Figure 1 is a diagram showing the configuration of the oil pump discharge rate switching device 1. Figure 2 is a diagram showing the configuration of the continuously variable transmission 110 to which the oil pump discharge rate switching device 1 is applied.

The continuously variable transmission 110 is connected to the crankshaft of the engine 160, for example, via a torque converter (not shown), and converts and outputs the driving force from the engine 160. The continuously variable transmission 110 has a primary shaft (input shaft) 120 connected to the output shaft of the torque converter, and a secondary shaft (output shaft) 130 arranged in parallel to the primary shaft 120.

The primary shaft 120 is provided with a primary pulley 121. The primary pulley 121 has a fixed sheave 121a joined to the primary shaft 120 and a movable sheave 121b that faces the fixed sheave 121a and is mounted so as to be slidable in the axial direction of the primary shaft 120 and non-rotatable relative thereto, and is configured to be able to change the cone surface spacing of the sheaves 121a and 121b, i.e., the pulley groove width. On the other hand, the secondary shaft 130 is provided with a secondary pulley 131. The secondary pulley 131 has a fixed sheave 131a joined to the secondary shaft 130 and a movable sheave 131b that faces the fixed sheave 131a and is mounted so as to be slidable in the axial direction of the secondary shaft 130 and non-rotatable relative thereto, and is configured to be able to change the pulley groove width.

A chain 140 that transmits driving force is stretched between the primary pulley 121 and the secondary pulley 131. The gear ratio is continuously changed by changing the groove width of the primary pulley 121 and the secondary pulley 131 to change the ratio of the winding diameter of the chain 140 to each of the pulleys 121, 131 (pulley ratio). If the winding diameter of the chain 140 around the primary pulley 121 is Rp and the winding diameter around the secondary pulley 131 is Rs, the gear ratio i is expressed as i = Rs/Rp. The gear shift speed is expressed as di/dt.

Here, a primary drive oil chamber (hydraulic cylinder chamber) 122 is formed in the primary pulley 121 (movable sheave 121b). Meanwhile, a secondary drive oil chamber (hydraulic cylinder chamber) 132 is formed in the secondary pulley 131 (movable sheave 131b). The groove widths of the primary pulley 121 and the secondary pulley 131 are set and changed by adjusting the primary hydraulic pressure introduced into the primary drive oil chamber 122 and the secondary hydraulic pressure introduced into the secondary drive oil chamber 132.

The hydraulic pressure for shifting the continuously variable transmission 110, i.e., the primary hydraulic pressure and secondary hydraulic pressure described above, are controlled by a control valve (valve body) (not shown). The control valve adjusts the hydraulic pressure (hereinafter also referred to as "line pressure") discharged from the oil pump 10 by opening and closing an oil passage formed therein using a plurality of spool valves and a solenoid valve (electromagnetic valve) that operates the spool valve, and supplies the hydraulic pressure to the primary driving oil chamber 122 and the secondary driving oil chamber 132 of the continuously variable transmission 110 described above. The control valve also supplies the adjusted hydraulic pressure (operating hydraulic pressure, lubricating hydraulic pressure, etc.) to each hydraulic mechanism (hydraulic circuit) such as a forward/reverse switching mechanism that switches the vehicle forward/reverse. Note that FIG. 1 shows only a part of the circuits of the control valve (the line pressure adjustment circuit and the discharge state switching circuit).

The oil pump 10 is driven by the engine output, and draws in the oil (ATF) stored in the oil pan through the first intake oil passage 80A and the intake port 106, pressurizes the oil, and discharges it from two outlets (first outlet 107A and second outlet 107B). As the oil pump 10, for example, a two-port trochoid pump having two outlets is preferably used. Note that a two-port vane pump may be used instead of the trochoid pump. Also, the oil pump may be configured to have two intake ports corresponding to the two outlets (first outlet 107A and second outlet 107B).

The first discharge port 107A is connected to the first line pressure oil passage 70A (corresponding to the high pressure oil passage described in the claims), and the oil discharged from the first discharge port 107A is pressure-fed to the first line pressure oil passage 70A. On the other hand, the second discharge port 107B is connected to the second line oil passage 70B, and the oil discharged from the second discharge port 107B is pressure-fed to the second line oil passage 70B. The second line pressure oil passage 70B is configured to be connected to the first line pressure oil passage 70A via the switching control valve 60 (details will be described later).

The first line pressure oil passage 70A is provided with a line pressure control valve 30 for adjusting the oil pressure (discharge pressure) of the oil discharged from the oil pump 10 to the oil pressure (line pressure) required by the continuously variable transmission 110.

The line pressure control valve 30 is connected to a first control pressure oil passage 91, which communicates with the line pressure linear solenoid 20 described later, a first line pressure oil passage 70A, and a drain oil passage 93 that discharges oil. The line pressure control valve 30 accommodates a spool 31 inside so that it can slide axially. A spring 32 is disposed at the end of the spool 31, and the amount of oil discharged from the first line pressure oil passage 70A to the drain oil passage 93 is adjusted by driving the spool 31 axially according to the balance between the pressing force (line pressure control pressure x pressure receiving area) due to the line pressure control pressure generated by the line pressure linear solenoid 20 and the spring force (biasing force) of the spring 32, thereby adjusting the line pressure.

That is, when the spring force (biasing force) of the spring 32 is greater than the pressing force due to the line pressure control pressure, the line pressure control valve 30 connects the first line pressure oil passage 70A to the drain oil passage 93 and adjusts the line pressure by discharging the oil in the first line pressure oil passage 70A through the drain oil passage 93. On the other hand, when the spring force (biasing force) of the spring 32 is less than the pressing force due to the line pressure control pressure, the line pressure control valve 30 cuts off the communication between the first line pressure oil passage 70A and the drain oil passage 93 and stops discharging oil from the first line pressure oil passage 70A.

The line pressure linear solenoid 20 has a linear solenoid that displaces a valve in the axial direction according to the current value applied from the transmission control unit (hereinafter referred to as "TCU") 150 based on the line pressure required for the continuously variable transmission 110, and adjusts the line pressure control pressure by adjusting the balance between the supply pressure and the drain from the first line pressure oil passage 70A according to the current applied to the linear solenoid. The adjusted line pressure control pressure is supplied to the line pressure control valve 30 through the first control pressure oil passage 91, and the line pressure control valve 30 is driven and controlled as described above. Here, as the current value applied to the line pressure linear solenoid 20 increases, the line pressure control pressure increases linearly, and accordingly, the actual line pressure also increases linearly.

As described above, the second discharge port 107B of the oil pump 10 is connected to the first line pressure oil passage 70A via the second line pressure oil passage 70B and the switching control valve 60. In addition, the second discharge port 107B of the oil pump 10 is connected directly or indirectly to the first intake oil passage 80A via the second line pressure oil passage 70B, the switching control valve 60, and the second intake oil passage 80B.

The switching control valve 60 switches the destination of the oil discharged from the second discharge port 107B between the first line pressure oil passage 70A (high pressure oil passage) and the second intake oil passage 80B (low pressure oil passage) that directly or indirectly communicates with the first intake oil passage 80A (intake port 106) based on the spring force (biasing force) of the spring 62 and the pressing force of the switch oil pressure generated by the switch pressure solenoid 50 described below.

More specifically, the switching control valve 60 is connected to a second control pressure oil passage (switch pressure oil passage) 92 communicating with the switch pressure solenoid 50, a first line pressure oil passage 70A, a second line pressure oil passage 70B communicating with the second discharge port 107B, and a second intake oil passage 80B directly or indirectly communicating with the first intake oil passage 80A (intake port 106). The switching control valve 60 accommodates a spool 61 therein so as to be slidable in the axial direction. A spring 62 is disposed at one end of this spool 61, and the spool 61 is driven axially in accordance with the balance between the spring force (springing force) F _spring (= K × X (spring collapse allowance)) of the spring 62 and the pressing force F _SW (switch oil pressure P _SW × pressure-receiving area A _SW ) by the switch oil pressure P _SW generated by the switch pressure solenoid 50, so that the oil passage communicating with the second line pressure oil passage 70B is switched between the first line pressure oil passage 70A and the second suction oil passage 80B.

More specifically, when the spring force is greater than the pressing force of the switch hydraulic pressure, the switching control valve 60 switches so that the second line pressure oil passage 70B communicates with the first line pressure oil passage 70A, i.e., the destination of the oil discharged from the second discharge port 107B is the first line pressure oil passage 70A. On the other hand, when the spring force is less than the pressing force of the switch hydraulic pressure, the switching control valve 60 switches so that the second line pressure oil passage 70B communicates with the second intake oil passage 80B, i.e., the destination of the oil discharged from the second discharge port 107B is the second intake oil passage 80B.

Therefore, when the switch pressure solenoid 50 described later supplies the switch control valve 60 with a switch pressure solenoid 50, the switch control valve 60 switches the second line pressure oil passage 70B to communicate with the second suction oil passage 80B, i.e., the destination of the oil discharged from the second discharge port 107B is the second suction oil passage 80B (so that the oil is in a half-discharge state). On the other hand, when the switch pressure solenoid 50 does not supply the switch pressure solenoid 50 (when the switch pressure is zero), the switch control valve 60 switches the second line pressure oil passage 70B to communicate with the first line pressure oil passage 70A, i.e., the destination of the oil discharged from the second discharge port 107B is the first line pressure oil passage 70A (so that the oil is in a full discharge state).

Based on the operating state of the continuously variable transmission 110 and the like (details will be described later), the switch pressure solenoid 50 generates a switch hydraulic pressure (switching hydraulic pressure) that switches the destination of the oil discharged from the second discharge port 107B between the first line pressure oil passage 70A and the second intake oil passage 80B (i.e., switches between a full discharge state and a half discharge state). The above-mentioned first line pressure oil passage 70A and the second control pressure oil passage (switch pressure oil passage) 92 are connected to the switch pressure solenoid 50. When the switch pressure solenoid 50 is opened, the supply pressure from the first line pressure oil passage 70A is supplied as the switch hydraulic pressure (switching hydraulic pressure) to one end of the switching control valve 60 (the side facing the spring 62) through the second control pressure oil passage 92. On the other hand, when the switch pressure solenoid 50 is closed, the supply of the switch hydraulic pressure is stopped. At that time, the oil in the second control pressure oil passage 92 is drained, and the switch hydraulic pressure is set to zero.

As the switch pressure solenoid 50, for example, an on/off solenoid that opens when a voltage is applied and closes when the application of voltage is stopped is preferably used. Note that the relationship between the application/stop of voltage and the opening/closing of the valve may be reversed (normally open). The opening/closing of the switch pressure solenoid 50 is controlled by the TCU 150.

A line pressure sensor 153 that detects line pressure (oil pressure) is attached to the first line pressure oil passage 70A. The line pressure sensor 153 is electrically connected to the TCU 150, and the output of the line pressure sensor 153, i.e., an electrical signal (e.g., voltage) corresponding to the line pressure, is read by the TCU 150.

In addition to the line pressure sensor 153, various sensors are connected to the TCU 150, including a range switch 151 that detects the selected position of the shift lever, and an oil temperature sensor 152 that detects the temperature of the oil in the continuously variable transmission 110. The TCU 150 is also connected to an engine control unit (hereinafter referred to as "ECU") 170, which comprehensively controls the engine 160, and a vehicle dynamic control unit (hereinafter referred to as "VDCU") 180, which suppresses skidding and ensures vehicle stability during cornering by controlling the brakes through automatic pressurization and the torque of the engine 160, via a CAN (Controller Area Network) 190, so that they can communicate with each other.

The ECU 170 is connected to a crank angle sensor 171 that detects the position of the crankshaft of the engine 160, an accelerator pedal position sensor 172 that detects the opening of the accelerator pedal, and the like. The ECU 170 determines the engine speed from the change in the rotational position of the crankshaft detected by the crank angle sensor 171. The ECU 170 transmits information such as the engine speed, accelerator pedal position, coolant temperature, and engine torque to the TCU 150, etc., via the CAN 190.

On the other hand, the VDCU 180 is connected to a wheel speed sensor 181 that detects the rotational speed (vehicle speed) of each wheel of the vehicle, an acceleration sensor 182 that detects the acceleration in the front, rear, left and right directions of the vehicle, a brake switch that detects whether the brake pedal is depressed, a brake fluid pressure sensor that detects the master cylinder pressure (brake hydraulic pressure) of the brake actuator, and a steering angle sensor. The VDCU 180 transmits information such as the detected wheel speed (vehicle speed), the acceleration in the front, rear, left and right directions of the vehicle, and braking information (brake operation information) such as the brake switch and brake fluid pressure to the TCU 150 via the CAN 190.

The TCU 150 receives information such as engine speed and accelerator opening from the ECU 170 via the CAN 190, and also receives information such as vehicle speed and vehicle acceleration from the VDCU 180. Note that the vehicle speed information may be calculated from the rotation speed of the secondary shaft 130 and the total gear ratio between the secondary shaft 130 and the wheels.

The TCU 150 is configured with a microprocessor that performs calculations, an EEPROM that stores programs for causing the microprocessor to execute various processes, a RAM that stores various data such as the results of calculations, a backup RAM whose stored contents are maintained by a battery, and an input/output I/F, etc.

The TCU 150 automatically and steplessly changes the gear ratio according to the vehicle's operating conditions (e.g., accelerator pedal depression and vehicle speed) in accordance with a shift map based on various information acquired from the above-mentioned various sensors, etc. The shift map is stored in an EEPROM or the like in the TCU 150. The TCU 150 also controls the drive of the above-mentioned line pressure linear solenoid 20, switch pressure solenoid 50, etc. In other words, the TCU 150 switches the discharge state of the oil pump 10 (full discharge state and half discharge state).

In particular, the TCU 150 has a function of expanding the operating range of the half discharge (partial discharge) state to further reduce the load on the oil pump 10. For this reason, the TCU 150 is functionally equipped with a discharge state switching unit 150a, a target oil pressure setting unit 150b, a pressure adjustment unit 150c, a learning unit 150d, a correction value acquisition unit 150e, and an abnormality determination unit 150f. In the TCU 150, a program stored in an EEPROM or the like is executed by a microprocessor to realize the functions of the discharge state switching unit 150a, the target oil pressure setting unit 150b, the pressure adjustment unit 150c, the learning unit 150d, the correction value acquisition unit 150e, and the abnormality determination unit 150f.

The discharge state switching unit 150a drives the switch pressure solenoid 50 based on a predetermined discharge state switching condition (details will be described later) to switch the discharge state of the oil pump 10 to a full discharge state in which the two discharge ports (first discharge port 107A, second discharge port 107B) are connected to the first line pressure oil passage 70A (high pressure oil passage), or a half discharge (partial discharge) state in which the first discharge port 107A of the two discharge ports (first discharge port 107A, second discharge port 107B) is connected to the first line pressure oil passage 70A and the second discharge port 107B is directly or indirectly connected to the intake port 106 (first intake oil passage 80A) of the oil pump 10. That is, the discharge state switching unit 150a, the switch pressure solenoid 50, and the switching control valve 60 function as the discharge state switching means described in the claims.

When a predetermined learning condition is satisfied, the target oil pressure setting unit 150b sets a learning target oil pressure that is higher than the target oil pressure during normal control in order to learn the saturated oil pressure of the first line pressure oil passage 70A (high pressure oil passage) that is correlated with the amount of oil leaking from the hydraulic circuit (hydraulic component). In other words, the target oil pressure setting unit 150b functions as a target oil pressure setting means as described in the claims.

When learning the saturated oil pressure of the first line pressure oil passage 70A, the target oil pressure setting unit 150b sets, for example, a value higher than the maximum pressure in the half-discharge state as the learning target oil pressure. Here, the maximum pressure in the half-discharge state can be obtained, for example, by storing in advance a map (half-discharge maximum pressure map) that defines the relationship between the engine speed, oil temperature, and maximum pressure, and searching the map with the engine speed and oil temperature. In addition, when setting the learning target oil pressure, the target oil pressure setting unit 150b preferably gradually increases the learning target oil pressure as shown in FIG. 3.

Alternatively, the target oil pressure setting unit 150b may be configured to gradually increase the learning target oil pressure until the oil pressure in the first line pressure oil passage 70A is saturated. When the target oil pressure setting unit 150b is not learning the saturated oil pressure in the first line pressure oil passage 70A (when a predetermined learning condition is not satisfied), i.e., during normal control, the target oil pressure setting unit 150b sets the target oil pressure (target line pressure) according to the vehicle operating conditions (e.g., vehicle speed, accelerator opening, etc.).

Here, the above-mentioned predetermined learning conditions preferably include at least one of the following: the discharge state of the oil pump 10 is a half discharge state, the engine speed (Ne) is within a predetermined speed range, the time change of the engine speed (ΔNe) is within a predetermined change range, the oil temperature is within a predetermined temperature range, the acceleration of the vehicle (body vibration) is equal to or lower than a predetermined value, and no manual shift operation is being performed. The learning target oil pressure (or the normal target oil pressure) set as described above is output to the pressure adjusting unit 150c.

When a predetermined learning condition is satisfied, the pressure adjusting unit 150c drives the line pressure linear solenoid 20 to adjust the pressure so that the actual oil pressure (actual line pressure) of the first line pressure oil passage 70A matches the learning target oil pressure. That is, the pressure adjusting unit 150c functions as a pressure adjusting means described in the claims. Note that when the pressure adjusting unit 150c does not learn the saturated oil pressure of the first line pressure oil passage 70A (when a predetermined learning condition is not satisfied), that is, during normal control, it adjusts the pressure so that the actual oil pressure (actual line pressure) of the first line pressure oil passage 70A matches the normal target oil pressure (target line pressure).

The learning unit 150d learns (acquires) the saturated oil pressure and engine speed (∝ oil pump speed ∝ oil pump discharge volume) when the oil pressure in the first line pressure oil passage 70A becomes saturated when a predetermined learning condition is satisfied and the pressure adjustment unit 150c is controlling the oil pressure in the first line pressure oil passage 70A to match the learning target oil pressure. For example, as shown in FIG. 3, the learning unit 150d determines that the oil pressure has become saturated when the actual oil pressure does not increase (does not change) for a predetermined time or more. In other words, the learning unit 150d functions as a learning means as described in the claims.

Even with the same engine speed (oil pump speed), an individual with a low discharge flow rate or a large amount of leakage will saturate at a low oil pressure, while an individual with a high discharge flow rate or a small amount of leakage will saturate at a high oil pressure. Therefore, by learning the saturation oil pressure, individual variations and deterioration over time can be understood. The saturation oil pressure and engine speed (learned value) when the oil pressure of the first line pressure oil passage 70A is saturated, acquired (learned) by the learning unit 150d, are output to the correction value acquisition unit 150e.

The correction value acquisition unit 150e acquires a correction value (correction coefficient) for correcting the discharge state switching condition (switching engine speed) based on a comparison between the saturation oil pressure and the learning target oil pressure at the engine speed learned by the learning unit 150d. In other words, the correction value acquisition unit 150e functions as the correction value acquisition means described in the claims.

The correction value acquisition unit 150e sets a correction value (correction coefficient) so that, at the learned engine speed, the higher the saturated oil pressure (i.e., the closer it gets to the learning target oil pressure), the lower the switch engine speed (switching permitted engine speed) at which switching from a full discharge state to a partial discharge state is permitted.

More specifically, the EEPROM of the TCU 150 stores a map (correction coefficient map) that defines the relationship between engine speed (rpm), saturated oil pressure (MPa), and a correction value (correction coefficient), and the correction coefficient is obtained by searching this correction coefficient map based on the engine speed and saturated oil pressure.

Here, an example of the correction coefficient map is shown in FIG. 4. In FIG. 4, the horizontal axis (rows) is the saturated oil pressure (MPa), and the vertical axis (columns) is the engine speed (rpm). In the correction coefficient map, a correction coefficient is given for each combination (grid point) of engine speed and saturated oil pressure. As shown in FIG. 4, the correction coefficient map is set so that the higher the saturated oil pressure, the larger the correction coefficient, and the higher the engine speed, the smaller the correction coefficient. Note that the example shown in FIG. 4 is a map of the correction value (correction coefficient) according to the saturated oil pressure when the learning target oil pressure is set to 4.0 (MPa).

Here, in order to prevent the learning control from only working at a specific rotation speed and to respond to all driving conditions, it is preferable to use a map according to the engine rotation speed (oil pump rotation speed) and the saturated oil pressure. Furthermore, when multiple learning values are acquired, the correction value acquisition unit 150e adopts the smallest (i.e., the safest) correction coefficient among the correction coefficients acquired from each learning value. The correction coefficient acquired by the correction value acquisition unit 150e is output to the discharge state switching unit 150a described above.

During normal control other than learning, the discharge state switching unit 150a corrects the discharge state switching condition (switching engine speed) using the correction value (correction coefficient) acquired by the correction value acquisition unit 150e. Then, the discharge state switching unit 150a switches between the full discharge state and the partial discharge state based on the corrected discharge state switching condition (switching engine speed, actual oil pressure in the first line pressure oil passage 70A). More specifically, when the learning correction coefficient is 1.2, for example, the discharge state switching unit 150a calculates "switching permission engine speed before correction (base value)/1.2" as the corrected switching permission engine speed.

Here, the EEPROM of the TCU 150 stores a map (half-discharge switching permission table) that defines the relationship between the actual oil pressure (MPa) of the first line pressure oil passage 70A and the switching engine speed (rpm), and the switching engine speed is obtained by searching this half-discharge switching permission table based on the actual oil pressure of the first line pressure oil passage 70A.

Here, an example of the half discharge switching permission table is shown in FIG. 5. In the half discharge switching permission table, the switching engine speed is given for each actual oil pressure (lattice point) of the first line pressure oil passage 70A. As shown in FIG. 5, the half discharge switching permission table is set so that the switching engine speed increases as the actual oil pressure of the first line pressure oil passage 70A increases. Here, in the half discharge switching permission table shown in FIG. 5, the upper part shows the half discharge switching permission table (switching engine speed) before correction, and the lower part shows the half discharge switching permission table (switching engine speed) after correction when the correction coefficient is 1.2. As shown in FIG. 5, the half discharge switching permission table (switching engine speed) after correction is 1/1.2 of the half discharge switching permission table (switching engine speed) before correction.

The discharge state switching unit 150a switches between the full discharge state and the half discharge state based on the acquired switchover engine speed. More specifically, when the engine speed is equal to or lower than the switchover engine speed, the discharge state switching unit 150a sets the discharge state of the oil pump 10 to the full discharge state. On the other hand, when the engine speed is higher than the switchover engine speed, the discharge state switching unit 150a sets the discharge state of the oil pump 10 to the half discharge (partial discharge) state. Therefore, as shown in FIG. 6, the engine speed (switchover engine speed) at which the half discharge state is switched is reduced (in the example of FIG. 6, it is reduced from 1400 (rpm) to 1167 (rpm)), and the operating range of the half discharge state is expanded.

The abnormality determination unit 150f determines that the hydraulic circuit (hydraulic components) is abnormal if the correction value (correction coefficient) falls outside a predetermined range and/or changes (fluctuations) by a predetermined value or more within a certain period of time. That is, the abnormality determination unit 150f functions as the abnormality determination means described in the claims. More specifically, the abnormality determination unit 150f determines that an abnormality has occurred when the correction coefficient is less than 0.5, for example. Alternatively, the abnormality determination unit 150f determines that an abnormality has occurred when the correction coefficient has changed suddenly by 0.1 or more within 60 seconds, for example.

Next, the operation of the oil pump discharge amount switching device 1 will be described with reference to FIG. 7. FIG. 7 is a flowchart showing the processing procedure of the learning process and the discharge amount (discharge state) switching process by the oil pump discharge amount switching device 1. This process is repeatedly executed at predetermined time intervals (e.g., every 10 ms) mainly by the TCU 150.

In step S100, a determination is made as to whether or not the predetermined learning conditions are satisfied. The predetermined learning conditions are as described above, and therefore will not be described in detail here. If the predetermined learning conditions are satisfied, processing proceeds to step S102. On the other hand, if the predetermined learning conditions are not satisfied, processing proceeds to step S200.

In step S102, a learning target oil pressure is set to learn the saturated oil pressure of the first line pressure oil passage 70A (high pressure oil passage), which is correlated with the amount of oil leaking from the hydraulic circuit. At that time, the learning target oil pressure is gradually increased with a certain gradient to a value that exceeds the maximum pressure in the half-discharge state (or until the oil pressure saturates) so that the actual oil pressure can follow. Note that the method for setting the learning target oil pressure is as described above, so a detailed explanation will be omitted here.

Next, in step S104, pressure regulation control is performed so that the actual oil pressure (actual line pressure) in the first line pressure oil passage 70A matches the learning target oil pressure.

Then, in step S106, the saturated oil pressure and engine speed when the oil pressure in the first line pressure oil passage 70A is saturated are acquired (learned).

Next, in step S108, a correction value (correction coefficient) for correcting the discharge state switching condition (switching engine speed) is obtained based on a comparison between the saturation oil pressure and the learning target oil pressure at the learned engine speed. Note that the method for obtaining the correction value (correction coefficient) is as described above, so a detailed explanation is omitted here. After that, the process proceeds to step S200.

If step S100 is negative (the predetermined learning conditions are not satisfied), or when the learning process is completed, normal control is executed based on the corrected discharge state switching conditions (switching engine speed). That is, in step S200, the target oil pressure is returned from the learning target oil pressure to the normal target oil pressure (target line pressure), and the corrected switching engine speed corresponding to the actual oil pressure in the first line pressure oil passage 70A is obtained.

Next, in step S202, a determination is made as to whether the engine speed is equal to or lower than the switchover engine speed. If the engine speed is equal to or lower than the switchover engine speed, in step S204, the discharge state of the oil pump 10 is set to the full discharge state. Then, the process is temporarily terminated.

On the other hand, when the engine speed is higher than the switchover engine speed, the discharge state of the oil pump 10 is set to a half-discharge state in step S206. Then, the process is temporarily terminated.

As described above in detail, according to this embodiment, when a predetermined learning condition is satisfied, a learning target oil pressure higher than the target oil pressure during normal control is set to learn the saturated oil pressure of the first line pressure oil passage 70A, which is correlated with the amount of oil leaking from the hydraulic circuit, and when pressure regulation control is performed so that the oil pressure of the first line pressure oil passage 70A matches the learning target oil pressure, the saturated oil pressure and engine speed when the oil pressure of the first line pressure oil passage 70A is saturated are learned, and a correction value (correction coefficient) for correcting the discharge state switching condition (switching engine speed) is obtained based on a comparison between the saturated oil pressure and the learning target oil pressure at the learned engine speed. Then, during normal control other than learning, the discharge state switching condition (switching engine speed) is corrected using the correction value (correction coefficient), and the full discharge state and the partial discharge state are switched based on the corrected discharge state switching condition (switching engine speed). Therefore, taking into account individual variations in the amount of leakage from the hydraulic circuit and deterioration over time, the margin (i.e., the margin that takes into account part variations and deterioration over time) of the discharge state switching condition (switching engine speed) can be lowered. As a result, the operating range of the half-discharge state can be expanded, the load on the oil pump 10 can be further reduced, and the fuel consumption rate (fuel economy) can be further reduced.

According to this embodiment, the predetermined learning conditions include at least one of the following: the discharge state of the oil pump 10 is a partial discharge state, the engine speed (Ne) is within a predetermined range, and the time change (ΔNe) of the engine speed is within a predetermined change range; the oil temperature (oil temperature) is within a predetermined temperature range, the vehicle acceleration (body vibration) is equal to or lower than a predetermined value, and manual shift (manual gear change) operation is not being performed. Therefore, it is possible to select a state in which the hydraulic pressure is stable (a state in which the hydraulic pressure fluctuation is small) and perform learning, and it is possible to more accurately learn the saturated hydraulic pressure of the first line pressure oil passage 70A, i.e., the leakage amount of the hydraulic circuit.

According to this embodiment, the correction value is set so that the higher the saturated oil pressure, the lower the switchover engine speed. Therefore, the higher the saturated oil pressure (i.e., the smaller the amount of leakage), the lower the switchover engine speed for switching to the partial discharge state, making it possible to extend the half discharge state.

According to this embodiment, the full discharge state and the partial discharge state are switched based on the corrected switchover engine speed, i.e., the switchover engine speed (∝ oil pump speed ∝ oil pump discharge amount) that takes into account the amount of leakage in the hydraulic circuit, and the actual oil pressure in the first line pressure oil passage 70A. This makes it possible to expand the partial discharge state more accurately.

According to this embodiment, if the correction value (correction coefficient) falls outside a predetermined range and/or changes (fluctuations) by a predetermined value or more within a certain period of time, it is determined that the hydraulic circuit (hydraulic components) is abnormal. Therefore, in addition to expanding the operating range in the partial discharge state, it is also possible to detect abnormalities in the hydraulic circuit.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications are possible. For example, a configuration may be adopted in which multiple learning values (saturation oil pressure, engine speed) are learned, and the smallest (i.e., the safest) correction coefficient is adopted among the correction coefficients obtained from each learning value.

In the above embodiment, the present invention is applied to a continuously variable transmission (CVT) 110, but the present invention can also be applied to a stepped automatic transmission (Step AT) or DCT. In addition, in the above embodiment, the present invention is applied to a chain-type continuously variable transmission (CVT) 110, but instead of a chain-type continuously variable transmission, the present invention can also be applied to, for example, a belt-type continuously variable transmission or a toroidal-type continuously variable transmission.

In the above embodiment, a trochoid pump is used as the oil pump 10, but instead of the trochoid pump, for example, a vane pump or an internal gear type gear pump can be used. Also, instead of a mechanical oil pump driven by the engine, an electric oil pump (EOP) driven by an electric motor or the like can be used. When an electric oil pump (EOP) is used, the actual rotation speed of the electric oil pump (EOP) is used instead of the engine rotation speed.

In the above embodiment, an on-off solenoid is used as the switch pressure solenoid 50, but instead of the on-off solenoid, for example, a duty solenoid or a linear solenoid may be used.

REFERENCE SIGNS LIST 1 Oil pump discharge amount switching device 10 Oil pump 106 Intake port 107A First outlet port 107B Second outlet port 20 Line pressure linear solenoid 30 Line pressure control valve 50 Switch pressure solenoid 60 Switching control valve 70A First line pressure oil passage 70B Second line pressure oil passage 80A First intake oil passage 80B Second intake oil passage 91 First control pressure oil passage 92 Second control pressure oil passage 93 Drain oil passage 110 Continuously variable transmission 122 Primary drive oil chamber 150 TCU
150a Discharge state switching unit 150b Target oil pressure setting unit 150c Pressure adjustment unit 150d Learning unit 150e Correction value acquisition unit 150f Abnormality determination unit 151 Range switch 152 Oil temperature sensor 153 Line pressure sensor 160 Engine 170 ECU
171 Crank angle sensor 172 Accelerator opening sensor 180 VDCU
181 Vehicle speed sensor 182 Acceleration sensor 190 CAN

Claims (5)

an oil pump having a first discharge port and a second discharge port for discharging pressurized oil;
a discharge state switching means for switching a discharge state of the oil pump between a full discharge state in which the first discharge port and the second discharge port are connected to a high pressure oil passage, or a partial discharge state in which the first discharge port is connected to the high pressure oil passage and the second discharge port is connected to a suction port of the oil pump, based on a predetermined discharge state switching condition;
a target oil pressure setting means for setting a learning target oil pressure higher than the target oil pressure during normal control in order to learn a saturated oil pressure of the high pressure oil passage, which is correlated with an amount of oil leaking from the hydraulic circuit, when a predetermined learning condition is satisfied;
a pressure adjusting means for adjusting the pressure of the high pressure oil passage so that the oil pressure of the high pressure oil passage coincides with the learning target oil pressure when a predetermined learning condition is satisfied;
a learning means for learning a saturated oil pressure and an engine speed when the oil pressure in the high pressure oil passage is saturated while the pressure regulating means is controlling the oil pressure in the high pressure oil passage so that the oil pressure in the high pressure oil passage coincides with the learning target oil pressure;
a correction value acquisition means for acquiring a correction value for correcting the discharge state switching condition based on a comparison between the saturation oil pressure and the learning target oil pressure at the engine speed learned by the learning means,
The target oil pressure setting means, when setting the learning target oil pressure, gradually increases the learning target oil pressure with a certain gradient until the learning target oil pressure exceeds the maximum pressure in the partial discharge state or until the oil pressure in the high-pressure oil passage is saturated,
The learning means determines that the oil pressure in the high-pressure oil passage is saturated when the oil pressure in the high-pressure oil passage does not increase for a predetermined time or more,
The discharge state switching means corrects the discharge state switching condition using the correction value acquired by the correction value acquisition means during normal control other than learning, and switches between the full discharge state and the partial discharge state based on the corrected discharge state switching condition. The oil pump discharge amount switching device according to claim 1, characterized in that the predetermined learning conditions include at least one of the following: the discharge state of the oil pump is a partial discharge state, the engine speed is within a predetermined range of speeds, and the time change in the engine speed is within a predetermined range of changes, in addition to the oil temperature being within a predetermined temperature range, the vehicle acceleration being equal to or lower than a predetermined value, and no manual shift operation being performed. The discharge state switching condition includes a switching engine speed that allows switching from a full discharge state to a partial discharge state,
3. The oil pump discharge amount switching device according to claim 1, wherein the correction value acquisition means sets the correction value so that the switch engine speed decreases as the saturated oil pressure increases at the learned engine speed. The oil pump discharge amount switching device described in claim 3, characterized in that the discharge state switching means switches between the full discharge state and the partial discharge state based on the corrected switching engine speed and the actual oil pressure in the high-pressure oil passage during normal control other than learning. an oil pump having a first discharge port and a second discharge port for discharging pressurized oil;
a discharge state switching means for switching a discharge state of the oil pump between a full discharge state in which the first discharge port and the second discharge port are connected to a high pressure oil passage, or a partial discharge state in which the first discharge port is connected to the high pressure oil passage and the second discharge port is connected to a suction port of the oil pump, based on a predetermined discharge state switching condition;
a target oil pressure setting means for setting a learning target oil pressure higher than the target oil pressure during normal control in order to learn a saturated oil pressure of the high pressure oil passage, which is correlated with an amount of oil leaking from the hydraulic circuit, when a predetermined learning condition is satisfied;
a pressure adjusting means for adjusting the pressure of the high pressure oil passage so that the oil pressure of the high pressure oil passage coincides with the learning target oil pressure when a predetermined learning condition is satisfied;
a learning means for learning a saturated oil pressure and an engine speed when the oil pressure in the high pressure oil passage is saturated while the pressure regulating means is controlling the oil pressure in the high pressure oil passage so that the oil pressure in the high pressure oil passage coincides with the learning target oil pressure;
a correction value acquisition means for acquiring a correction value for correcting the discharge state switching condition based on a comparison between the saturation oil pressure and the learning target oil pressure at the engine speed learned by the learning means;
an abnormality determination means for determining that the hydraulic circuit is abnormal when the correction value falls outside a predetermined range and/or when the correction value changes by a predetermined value or more within a certain period of time,
The discharge state switching means corrects the discharge state switching condition using the correction value acquired by the correction value acquisition means during normal control other than learning, and switches between the full discharge state and the partial discharge state based on the corrected discharge state switching condition .

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