Control device for vehicle

Abstract

To provide a control device for a vehicle that is able to operate an oil pump more appropriately according to an oil temperature.SOLUTION: A control device for a vehicle that controls an operating state of an electric oil pump for supplying oil to a portion that needs to be cooled or lubricated during traveling includes a controller that operates or stops the oil pump. The controller comprises: a vehicle speed detection unit that detects a vehicle speed; an oil temperature detection unit that detects a temperature of the oil; a permissible vehicle speed setting unit that decreases, according to an increase in the temperature of the oil, a permissible vehicle speed for permitting drive of the oil pump; and an oil pump drive determination unit that inhibits the drive of the oil pump when the vehicle speed is equal to or lower than the permissible vehicle speed and that permits the drive of the oil pump when the vehicle speed exceeds the permissible vehicle speed.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a device for controlling an oil pump that supplies oil to parts that require cooling and lubrication. [Background technology]

[0002] Patent Document 1 describes a control device for a vehicle drive system that aims to ensure the amount of oil from the electric oil pump while making the noise generated from the electric oil pump less noticeable even at low vehicle speeds. In the device of Patent Document 1, the rotation speed of the electric oil pump is set according to the degree of accelerator opening. Specifically, when the accelerator opening is large, a large driving force is generated, and the noise increases, whereas when the accelerator opening is small, the noise caused by the drive by the drive force source decreases and may fall below the noise generated by the electric oil pump.

[0003] Therefore, in the device of Patent Document 1, a predetermined range is set as a driving state, i.e., an area of ​​the accelerator opening, in which the noise caused by the driving force source generating driving force is lower than the noise caused by the electric oil pump, and when the accelerator opening falls within the predetermined range, the rotation speed of the electric oil pump is lowered to reduce the noise caused by the electric oil pump. That is, in the device of Patent Document 1, when the accelerator opening is outside the predetermined range, the noise generated by other than the electric oil pump becomes large, so the operation sound of the electric oil pump is hidden. In addition, in the device of Patent Document 1, when the accelerator opening is within the predetermined range, the noise is small, so the rotation speed of the electric oil pump is reduced. Patent Document 1 claims that such a configuration allows the operation sound of the electric oil pump to be hidden by noise generated by other mechanisms, and conversely, when the noise generated by other mechanisms is small, the rotation speed of the electric oil pump is reduced, so that the noise of the electric oil pump can be made less noticeable. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-144899 A Summary of the Invention [Problem to be solved by the invention]

[0005] An electric oil pump generates noise according to the load caused by pressurizing and discharging oil, while the load increases when the viscosity of the oil is high, and the viscosity of the oil increases as the oil temperature decreases. In the end, the noise generated by the electric oil pump tends to increase as the oil temperature decreases. For example, when the oil temperature is low and the viscous resistance is large, the operating noise of the electric oil pump may increase due to the increase in oil flow resistance when the oil passes through the oil passage. Therefore, as in the device of Patent Document 1, when the rotation speed of the electric oil pump is set according to the accelerator opening, there is a possibility that the oil may be insufficient or the operating noise of the electric oil pump may increase in order to supply a sufficient amount of oil. On the other hand, even if the operating noise of the electric oil pump is small because the oil temperature is high and the oil flow resistance is small, the rotation speed of the electric oil pump may be maintained low because the accelerator opening is within a predetermined range. Therefore, in the device of Patent Document 1, there is room for improvement in the control that ensures the supply amount of oil by the electric oil pump while suppressing the discomfort of the vehicle occupants due to the operating noise.

[0006] The present invention has been made in light of the above technical problems, and aims to provide a vehicle control device that can more appropriately operate an electric oil pump in accordance with oil temperature. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention provides a vehicle control device that controls the operating state of an electric oil pump for supplying oil to parts that require cooling or lubrication while driving, and is characterized in that the controller operates or stops the oil pump, and is equipped with a vehicle speed detection unit that detects the vehicle speed, an oil temperature detection unit that detects the temperature of the oil, an allowed vehicle speed setting unit that reduces the allowed vehicle speed at which operation of the oil pump is permitted in accordance with an increase in the oil temperature, and an oil pump drive determination unit that prohibits operation of the oil pump when the vehicle speed is equal to or lower than the allowed vehicle speed and allows operation of the oil pump when the vehicle speed exceeds the allowed vehicle speed. Effect of the Invention

[0008] The vehicle control device of the present invention is configured to permit the operation of an electric oil pump when the vehicle speed exceeds a predetermined permitted vehicle speed. The permitted vehicle speed is set according to the oil temperature, and specifically, is set to decrease according to an increase in the oil temperature. Therefore, compared to a case where the permitted vehicle speed for determining the operation of the oil pump is always set to a constant vehicle speed, the operating range of the oil pump can be widened. In addition, the operating noise of the oil pump becomes small when the viscous resistance of the oil is small and the oil flow resistance when supplying oil to the oil passage is small. In other words, the higher the oil temperature, the smaller the operating noise of the oil pump becomes, so that the operating noise of the oil pump can be blended into the running noise of the vehicle. Therefore, the operating range of the oil pump can be widened without impairing the comfort of the vehicle occupants due to the operating noise of the oil pump, and thus, it is possible to suppress a shortage of oil to parts that require cooling and lubrication. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an example of a vehicle equipped with a control device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram for explaining a part of a functional configuration of a control device according to an embodiment of the present invention. [Diagram 3] 2 is a map for determining whether to operate or stop the oil pump depending on the vehicle speed and the oil temperature. [Figure 4] 4 is a flowchart illustrating an example of control executed by a control device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described below based on the embodiments shown in the drawings. Note that the embodiments described below are merely examples of the present invention and are not intended to limit the present invention.

[0011] Fig. 1 shows an example of a drive system and a control system of a vehicle Ve that is a control target in an embodiment of the present invention. The vehicle Ve shown in Fig. 1 is configured to transmit the output torque of a drive power source 1 that outputs a drive power for running to drive wheels 3 via a transaxle 2, a differential gear (not shown), and the like. In addition, an electric oil pump (EOP) 4 is provided to supply oil for lubrication and cooling to the transaxle 2, the differential gear, and the like. Furthermore, the vehicle Ve is provided with a detection unit 5 and a controller (ECU) 6.

[0012] The vehicle Ve to be controlled in the embodiment of the present invention may be a vehicle equipped with an internal combustion engine such as an engine, a hybrid vehicle (not shown) using an engine and a motor (not shown) as a driving force source, a series type hybrid vehicle (not shown) equipped with an engine as a power source for driving a generator (not shown), or an electric vehicle (not shown) so-called a range extender, or any of various conventionally known vehicles.

[0013] 1, the vehicle Ve to be controlled in the embodiment of the present invention may be a front-wheel drive vehicle in which drive torque is transmitted to front wheels (drive wheels) 3 and drive force is generated at the front wheels 3. Alternatively, the vehicle Ve may be a rear-wheel drive vehicle in which drive torque is transmitted to rear wheels 7 via, for example, a propeller shaft (not shown) and drive force is generated at the rear wheels 7. Alternatively, the vehicle Ve may be a four-wheel drive vehicle provided with a transfer mechanism (not shown) in which drive torque is transmitted to both the front wheels 3 and the rear wheels 7 and drive force is generated at both the front wheels 3 and the rear wheels 7.

[0014] Oil pump 4 is an electric oil pump that generates oil pressure when driven by torque output from an actuator (motor) (not shown). Oil pump 4, for example, draws up oil that has accumulated in an oil pan (not shown) disposed under transaxle 2, and supplies the oil to transaxle 2 and a differential gear via a hydraulic circuit. Note that oil pump 4 may be any conventionally known electric oil pump that is capable of adjusting the amount of oil discharged and operating independently of the output of a driving force source.

[0015] The detection unit 5 is a device or apparatus for acquiring various data and information required for controlling the vehicle Ve, and includes, for example, a power supply unit, a microcomputer, a sensor, and an input / output interface. In particular, the detection unit 5 in the embodiment of the present invention is provided with an oil temperature sensor 5a for detecting the temperature of oil supplied to the transaxle 2 and the differential gear, and a vehicle speed sensor 5b for detecting the current speed of the vehicle Ve. The detection unit 5 is electrically connected to the controller 6, and is configured to output, as detection data, electric signals and the like corresponding to detected values ​​or calculated values ​​of the various sensors, devices, and the like described above to the controller 6.

[0016] The controller 6 is an electronic control device mainly composed of, for example, a microcomputer. Various data detected or calculated by the above-mentioned detection unit 5 are input to the controller 6. The controller 6 performs calculations using the input various data and pre-stored data, calculation formulas, etc. Then, the controller 6 is configured to output the calculation results as control command signals and control the vehicle Ve as described above. Note that the detection unit 5, the ECU 6, and each actuator and sensor for driving the vehicle Ve are electrically connected to each other, for example, by a CAN or a wire harness, and output an electric signal corresponding to the acquired detection value or calculation value to the ECU 6 as detection data. Also, while FIG. 1 shows an example in which one controller 6 is provided, a plurality of controllers 6 may be provided for each device or equipment to be controlled, or for each control content.

[0017] In the vehicle Ve configured as described above, it is determined whether or not to drive the oil pump 4 based on the vehicle speed. The permitted vehicle speed for determining whether or not to permit the driving of the oil pump 4 is set based on the oil temperature. As shown in FIG. 2, the controller 6 includes a vehicle speed detection unit 8, an oil temperature detection unit 9, an oil pump drive determination unit 10, and a permitted vehicle speed setting unit 11 as functional configurations for setting a predetermined vehicle speed that is the permitted vehicle speed and permitting the driving of the oil pump 4.

[0018] The vehicle speed detection unit 8 acquires the current speed of the vehicle Ve detected by the vehicle speed sensor 5b. The oil temperature detection unit 9 acquires the current oil temperature based on the detection value of the oil temperature sensor 5a. The oil temperature detection unit 9 detects the temperature of the oil supplied by the oil pump 4. For this reason, the oil temperature detection unit 9 is configured to detect or calculate, for example, the temperature of oil remaining in an oil pan (not shown) or an oil temperature equivalent thereto.

[0019] The oil pump drive determination unit 10 permits the drive of the oil pump 4 in accordance with the vehicle speed. As shown in FIG. 3, the oil pump drive determination unit 10 has a predetermined ON-OFF switching map for the oil pump 4. As shown in FIG. 3, the map has a vertical axis representing the vehicle speed and a horizontal axis representing the oil temperature, and includes a predetermined vehicle speed for determining whether or not to permit the oil pump 4 to be driven. The oil pump drive determination unit 10 operates the oil pump 4 when the vehicle speed exceeds a predetermined vehicle speed indicated by a broken line in the map shown in FIG. 3. Conversely, when the vehicle speed is equal to or lower than the predetermined vehicle speed indicated by a broken line in the map shown in FIG. 3, the oil pump drive determination unit 10 is configured to prohibit the operation of the oil pump 4.

[0020] The permitted vehicle speed setting unit 11 sets a predetermined vehicle speed, which is a permitted vehicle speed for determining whether or not to permit the oil pump 4 to be driven. That is, the permitted vehicle speed setting unit 11 sets the predetermined vehicle speed in a map shown in FIG. 3. The predetermined vehicle speed is set based on the vehicle speed of the vehicle Ve and the oil temperature. As shown in FIG. 3, the predetermined vehicle speed is set constant at a relatively high vehicle speed when the oil temperature is relatively low. Then, after the oil temperature reaches the predetermined temperature T, the predetermined vehicle speed is set to decrease in accordance with the increase in the oil temperature. That is, the predetermined vehicle speed is set so that the oil pump 4 operates at a lower vehicle speed as the oil temperature increases.

[0021] The predetermined vehicle speed is set according to the magnitude of the operating sound of the oil pump 4 and noises generated from sources other than the oil pump 4, the amount of oil supply required for lubrication and cooling, and the like. Noises generated from sources other than the oil pump 4, i.e., background noises, include running sounds, operating sounds of the engine and motor as driving force sources, and sounds due to meshing of gears constituting the transaxle 2 and the differential gear. For example, since running sounds increase as the vehicle speed increases, when the vehicle speed is high, even if the operating sound of the oil pump 4 is loud, it can be drowned out by the running sound. Such a relationship between the magnitude of the operating sound of the oil pump 4 and background noises generated from sources other than the oil pump 4 that can drown out the operating sound is obtained in advance by experiments, simulations, and the like.

[0022] In addition, the operating noise of the oil pump 4 changes depending on the oil temperature. For example, the lower the oil temperature and the greater the viscous resistance of the oil, the greater the oil flow resistance, and therefore a large torque is required to pump the oil to the hydraulic circuit, etc. Therefore, the torque output from the actuator (not shown) increases, and the operating noise of the oil pump 4 increases. Conversely, the smaller the viscous resistance of the oil, the smaller the oil flow resistance to the hydraulic circuit, etc., and therefore the smaller the operating noise of the oil pump 4. The predetermined vehicle speed is set as shown in the map shown in FIG. 3 by conducting experiments and simulations in advance, taking into consideration the characteristics of the oil and the oil pump 4, the operating noise of the oil pump 4, and background noise.

[0023] Next, a control example in the embodiment of the present invention will be described with reference to the flowchart shown in FIG. 4. The flowchart shown in FIG. 4 is an example of control when determining whether or not to immediately operate the oil pump 4 when an operation command for the oil pump 4 is received. As shown in FIG. 4, in step S1, it is determined that an operation command for the oil pump 4 is received. For example, when the ignition of the vehicle Ve is turned ON, it becomes necessary to supply oil to parts of the vehicle Ve that require cooling and lubrication, such as the transaxle 2 and the differential gear, so an operation command is sent to the oil pump 4. When there is no operation command for the oil pump 4 and therefore the result is NO in step S1, the flow chart is temporarily ended without executing the subsequent control.

[0024] On the other hand, if the determination in step S1 is YES due to a command to operate the oil pump 4, the process proceeds to step S2. In step S2, it is determined that the current speed of the vehicle Ve is equal to or lower than a predetermined vehicle speed. As described above, this predetermined vehicle speed is set according to the oil temperature.

[0025] Specifically, the predetermined vehicle speed is set based on a predetermined ON-OFF switching map for the oil pump 4, as shown in Fig. 3. When the oil temperature is relatively low, the predetermined vehicle speed is set constant at a relatively high vehicle speed, as shown in Fig. 3. After the oil temperature reaches the predetermined temperature T, the predetermined vehicle speed is set to decrease as the oil temperature increases.

[0026] The predetermined vehicle speed is set according to the operating sound and background noise of the oil pump 4, the supply amount of oil required for lubrication and cooling, and the like. As described above, the operating sound of the oil pump 4 becomes louder as the oil flow resistance due to the viscous resistance of the oil increases. Also, background noise such as running noise increases as the vehicle speed increases. That is, the operating sound of the oil pump 4 can be hidden by increasing the vehicle speed. Alternatively, even if the vehicle speed is low, if the oil temperature is high, the operating sound of the oil pump 4 becomes small, so that the operating sound of the oil pump 4 can be hidden. Therefore, the relationship between the oil temperature and the vehicle speed at which the background noise is large enough to hide the operating sound of the oil pump 4 is obtained in advance by performing experiments, simulations, and the like, and the predetermined vehicle speed is set based on the results.

[0027] Therefore, in step S2, the current vehicle speed and oil temperature are acquired, and the map in Fig. 3 is referenced based on them. Then, the position plotted on the map in Fig. 3 is compared with the position of the dashed line indicating a predetermined vehicle speed. As a result, if the position plotted on the map in Fig. 3 is above the dashed line shown in Fig. 3, the result in step S2 is NO, and the process proceeds to step S4.

[0028] When the process proceeds to step S4, operation of the oil pump 4 is permitted. That is, based on the map of FIG. 3, the relationship between the oil temperature and the vehicle speed indicates that the background noise is sufficiently large compared to the operating noise of the oil pump 4. Therefore, even if the oil pump 4 operates, the operating noise of the oil pump 4 is smaller than background noise such as the running noise of the vehicle Ve, so that the operating noise of the oil pump 4 can be blended into the background noise. Therefore, the oil pump 4 is controlled to start operating in accordance with the operation command.

[0029] On the other hand, if the position plotted on the map in FIG. 3 is below the predetermined vehicle speed, that is, on or below the dashed line in FIG. 3, then the determination in step S2 is YES, and the process proceeds to step S3. In step S3, the operation of the oil pump 4 is temporarily prohibited because the vehicle speed has not reached the predetermined vehicle speed. Then, referring to the map shown in FIG. 3, the operation of the oil pump 4 is delayed until the vehicle speed exceeds the predetermined vehicle speed. For example, in step S3, the vehicle speed and the oil temperature are continuously detected at predetermined intervals, and the operation of the oil pump 4 is controlled to start when the position plotted on the map in FIG. 3 reaches a position above the dashed line in FIG. 3 due to at least one of an increase in the vehicle speed and an increase in the oil temperature.

[0030] As described above, in the control device for the vehicle Ve in the embodiment of the present invention, whether or not to operate the electric oil pump 4 is determined according to the current speed of the vehicle Ve. Specifically, the control device is configured to operate the oil pump 4 when the current vehicle speed is equal to or higher than a predetermined vehicle speed determined by the oil temperature. The predetermined vehicle speed is set to decrease as the oil temperature increases after the oil temperature reaches or exceeds a predetermined temperature T. Therefore, the oil pump 4 is more likely to operate compared to a case in which the predetermined vehicle speed for determining whether to operate the oil pump 4 is set to a constant value regardless of the oil temperature. In other words, the operating range of the oil pump 4 can be expanded.

[0031] Furthermore, when the oil temperature is high, the viscous resistance of the oil is small, so the oil flow resistance when the oil passes through the oil passage is small, and the sound generated when the oil pump 4 is operated is small. Therefore, even when the specified vehicle speed is set to be low, the operating sound of the oil pump 4 is relatively small, so the operating sound of the oil pump 4 can be drowned out by background noise generated from sources other than the oil pump 4, such as traveling noise. Therefore, even when the oil pump 4 operates when the vehicle speed is relatively low, the operating sound of the oil pump 4 is drowned out by other noises, so it is possible to prevent the operating sound of the oil pump 4 from impairing the comfort of the occupants of the vehicle Ve. [Explanation of symbols]

[0032] 1. Driving force source 2 Transaxle 3 Drive wheels (front wheels) 4. Oil pump 5. Detection section 5a Oil temperature sensor 5b Vehicle speed sensor 6 Controller 7 Rear wheel 8 Vehicle speed detection section 9 Oil temperature detector 10 Oil pump operation determination unit 11 Permitted vehicle speed setting section Vehicle

Claims

[Claim 1] A vehicle control device that controls an operating state of an electric oil pump for supplying oil to parts that require cooling or lubrication while the vehicle is running, A controller that activates or stops the oil pump, The controller: A vehicle speed detection unit that detects a vehicle speed; an oil temperature detection unit for detecting the temperature of the oil; an allowed vehicle speed setting unit that reduces an allowed vehicle speed at which the oil pump is permitted to be driven in response to an increase in the temperature of the oil; an oil pump drive determination unit that prohibits the drive of the oil pump when the vehicle speed is equal to or lower than the permitted vehicle speed and permits the drive of the oil pump when the vehicle speed exceeds the permitted vehicle speed. A vehicle control device comprising:

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