JP2018177007A - Steering control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering control device capable of reducing fuel consumption when a fuel remaining amount is small.SOLUTION: A CPU 82 determines based on a steering angle θ whether or not a power steering device is in an assist mode in which assist is necessary or in a standby mode in which assist is not necessary. When the CPU 82 determines to be assist mode, it map-computes the flow rate of working oil from a flow control valve 50 to a hydraulic mechanism 20 using either a fuel consumption preference map or a steering preference map. The fuel consumption preference map is a map for computing so that the discharge flow rate of the working oil from the flow control valve 50 to the hydraulic mechanism 20 is less than that in the case of using the steering preference map. When a fuel remaining amount FR is small, the CPU 82 adopts the fuel consumption preference map.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hydraulic mechanism including: a power cylinder; and a switching unit that changes the sign of the assist force output by the power cylinder by switching an oil passage connected to the power cylinder; And a discharge control device for discharging the same.

  For example, in the following Patent Document 1, a device that changes the discharge flow rate of hydraulic fluid from an engine drive type pump driven by a vehicle-mounted internal combustion engine to a hydraulic mechanism having a power cylinder according to vehicle speed, steering speed and steering angle. Is described. Specifically, when it is determined that the steering assist is not necessary based on the vehicle speed, the steering speed, and the steering angle, the device determines the hydraulic fluid discharge flow rate more than when it is determined that the assist is necessary. It is less. This is intended to reduce fuel consumption by an internal combustion engine by reducing the amount of work of an engine-driven pump when assist is not necessary.

JP, 2006-143059, A

  The above device only sets the discharge flow rate in accordance with whether or not the assist is necessary. Therefore, when the assist is necessary, the discharge flow rate is set regardless of the fuel remaining amount. . For this reason, when priority is given to reduction of fuel consumption, it can not respond to this.

Hereinafter, the means for solving the above-mentioned subject and its operation effect are described.
1. The steering control device operates on the hydraulic mechanism and a hydraulic mechanism that includes a power cylinder, and a switching unit that changes the sign of the assist force output by the power cylinder by switching an oil passage connected to the power cylinder, and the hydraulic mechanism. The present invention is applied to a power steering apparatus including a discharge device that discharges oil, and a remaining amount acquisition process for acquiring a remaining fuel amount of a vehicle, and a case where the remaining amount of fuel acquired by the remaining amount acquisition process is small. Also, a reduction process is performed to operate the discharge device so that the flow rate of the hydraulic fluid discharged by the discharge device to the hydraulic mechanism is reduced.

  In the above configuration, the discharge device is operated so that the flow rate of the hydraulic oil decreases when the fuel remaining amount is small by the reduction process. Therefore, compared to the case where the reduction process is not performed, the amount of work performed by the discharge device is Reduced. As a result, the amount of energy consumed by the discharge device is reduced, so that the fuel consumption rate can be reduced when the remaining amount of fuel is small.

  2. In the steering control device according to the above-mentioned 1, it is determined based on the operation state of the steering of the vehicle whether the assist mode for generating the assist force or the standby mode for waiting without generating the assist force. Performing a determination process and an increase process for increasing the flow rate of the hydraulic fluid discharged by the discharge device to the hydraulic mechanism in the assist mode than in the standby mode; and performing the reduction process Execute on condition that it is mode.

  Since the above-mentioned standby mode is a mode when the assisting force is unnecessary, it is possible to make the discharge flow rate of the discharge device as small as possible. On the other hand, since the assist mode is a mode when an assist force is required, the discharge flow rate of the discharge device tends to be a value that increases the fuel consumption rate. Therefore, in the above configuration, the fuel consumption rate is reduced as compared with the case where the discharge flow rate in the standby mode is reduced when the fuel remaining amount is low by reducing the discharge flow amount in the assist mode when the fuel remaining amount is small. It is easy to do.

  3. In the steering control device according to the above 1 or 2, the destination acquisition processing for acquiring destination information of the vehicle is executed, and the reduction processing is performed for the amount of fuel necessary for the vehicle to reach the destination. It is executed on the condition that the margin of the fuel remaining amount is less than a predetermined value.

  Even if the amount of remaining fuel is small enough to reach the destination, there may be cases where it is not desirable to limit the assist power. In this respect, in the above configuration, the amount of fuel consumption can be obtained by executing the reduction process on the condition that the fuel remaining amount margin is less than a predetermined value with respect to the fuel amount necessary to reach the destination. The reduction process can be performed to reduce the amount of fuel consumption when it is particularly likely that it is desirable to suppress the.

  4. In the steering control device according to any one of the above 1 to 3, the discharge device includes an engine drive type pump driven by a vehicle-mounted internal combustion engine, and the hydraulic mechanism among the hydraulic fluid discharged by the pump. And a flow control valve for adjusting an amount returned to the upstream side of the pump without being discharged, wherein the reduction process is discharged from the discharge device to the hydraulic mechanism by operating the flow control valve. It is a process which controls the flow rate of the above-mentioned hydraulic fluid.

  In the above configuration, the pressure loss increases as the amount of hydraulic fluid discharged by the engine drive pump out of the hydraulic mechanism increases, so the power of the pump increases. For this reason, the fuel consumption rate of the internal combustion engine is increased by operating the flow control valve to increase the amount of hydraulic oil discharged by the engine-driven pump that is returned to the upstream side of the pump without being discharged to the hydraulic mechanism. Can be reduced.

FIG. 1 is a view showing configurations of a steering control device and a steering device according to a first embodiment. The flowchart which shows the procedure of the process regarding operation of the flow control valve concerning the embodiment. 5 is a flowchart showing a procedure of switching processing of an assist mode map according to the embodiment; 10 is a flowchart showing a procedure of switching processing of an assist mode map according to the second embodiment.

First Embodiment
Hereinafter, a first embodiment according to a steering control device will be described with reference to the drawings.
As shown in FIG. 1, the torque input to the steering wheel (steering 10) can be transmitted to the steered wheels 14 via the hydraulic power steering device 12. The power steering device 12 includes a rack and pinion mechanism that converts the rotation of the pinion shaft 22 that rotates in conjunction with the operation of the steering 10 into linear motion of the rack shaft 24 that meshes with the pinion shaft 22. The steered wheels 14 are connected to both ends of the rack shaft 24 via a ball joint or the like. The power steering device 12 assists the operation of the steering 10 by assisting the operation of the rack shaft 24 by the operation of the steering 10.

  The power steering device 12 stores, as a configuration for assisting the operation of the steering 10, a hydraulic mechanism 20, an engine drive type pump 42 driven by rotation of a crankshaft of an engine (internal combustion engine 46), and hydraulic oil. A tank 44 and a flow control valve 50 (discharge device) for adjusting the flow rate of the hydraulic fluid discharged by the pump 42 (discharge device) to the hydraulic mechanism 20 are provided.

  The hydraulic mechanism 20 includes a power cylinder 30 which incorporates a piston 34 and into which a rack shaft 24 is inserted. A piston 34 is fixed to the rack shaft 24 inside the power cylinder 30. The piston 34 divides the space inside the power cylinder 30 into a first hydraulic chamber 36 and a second hydraulic chamber 38. The difference between the pressure (hydraulic pressure) of the hydraulic fluid in the first hydraulic pressure chamber 36 and the pressure of the hydraulic fluid in the second hydraulic pressure chamber 38 generates a force that displaces the rack shaft 24 in either axial direction. This is the assist force.

  The hydraulic mechanism 20 also includes a steering valve (switching unit 40). The switching unit 40 is a rotary valve provided on the pinion shaft 22 and switching a supply path of hydraulic fluid to the power cylinder 30 and a discharge path of hydraulic fluid from the power cylinder 30 in conjunction with the rotation of the pinion shaft 22.

  Specifically, the switching unit 40 includes a discharge passage 25 into which hydraulic fluid discharged by the pump 42 flows via the flow control valve 50, a first supply / discharge passage 26 connected to the first hydraulic chamber 36, and a second A second supply / discharge passage 27 connected to the hydraulic pressure chamber 38 and a discharge passage 28 connected to the tank 44 are connected. The switching unit 40 communicates the discharge passage 25 with the first supply / discharge passage 26 and communicates the discharge passage 28 with the second supply / discharge passage 27, and communicates the discharge passage 25 with the second supply / discharge passage 27. And the state in which the discharge passage 28 is in communication with the first supply / discharge passage 26 is switched. Here, when the discharge passage 25 is in communication with the first supply / discharge passage 26 and the discharge passage 28 is in communication with the second supply / discharge passage 27, the pressure in the first hydraulic chamber 36 is the second hydraulic chamber 38. As a result, the piston 34 in the power cylinder 30 receives a net force in the first direction D1 of FIG. 1. This force is an assist force that displaces the rack shaft 24 in the first direction D1. On the other hand, when the discharge passage 25 is in communication with the second supply / discharge passage 27 and the discharge passage 28 is in communication with the first supply / discharge passage 26, the pressure in the second hydraulic chamber 38 is the first hydraulic chamber. As a result, the force in the second direction D2 of FIG. 1 is applied to the piston 34 in the power cylinder 30. This force is an assist force that displaces the rack shaft 24 in the second direction D2.

  The flow control valve 50 includes a cylindrical body 52, a cylindrical spool 54, an elastic member (spring 56), a solenoid 58 and a plunger 60. An orifice 62 is provided inside the body 52. A space inside the body 52 is divided into a first chamber 64 and a second chamber 66 with the orifice 62 as a boundary. The first chamber 64 is a discharge destination of the hydraulic fluid from the pump 42 to the flow rate control valve 50. The second chamber 66 is connected to the discharge passage 25.

  The spool 54 is accommodated in the first chamber 64 and is slidable along the axial direction. A spring 56 is accommodated on the side of the first chamber 64 opposite to the orifice 62 with respect to the spool 54. The spring 56 exerts an elastic force on the spool 54 toward the orifice 62. The spring chamber 70 in which the spring 56 is accommodated in the first chamber 64 is connected to the second chamber 66 by bypassing the orifice 62 via the bypass passage 72.

  The second chamber 66 is provided with a solenoid 58 and a plunger 60 inserted into the solenoid 58. A variable orifice is formed by the end face 60 a on the orifice 62 side of the pair of axial end faces of the plunger 60 and the orifice 62. That is, the plunger 60 is axially displaced in accordance with the electromagnetic force corresponding to the current supplied to the solenoid 58, whereby the degree of restriction of the variable orifice is variably set.

  A short loop passage 29 in communication with the suction side of the pump 42 is connected to the first chamber 64. The short loop passage 29 and the first chamber 64 are closed by the spool 54 when the pressure difference between the working oil before and after passing through the variable orifice is equal to or less than a predetermined value. On the other hand, when the pressure difference between the working oil before and after passing through the variable orifice exceeds a predetermined value, in other words, the pressure acting on the end face of the spool 54 on the orifice 62 side is the spring 56 side of the spool 54 The spool 54 is displaced toward the spring 56 when the pressure acting on the end face of the spool is larger than a predetermined pressure. As a result, the short loop passage 29 and the first chamber 64 are in communication.

  The EGECU 48 controls the internal combustion engine 46 and controls various control target devices attached to the internal combustion engine 46 to control control amounts (rotational speed, torque, exhaust component, etc.) of the internal combustion engine 46.

  The control device 80 (steering control device) controls the power steering device 12 and controls the assist force as the control amount by operating the flow control valve 50 as the operation target device. The control device 80 inputs the steering angle θ detected by the steering angle sensor 92 and the vehicle speed SPD detected by the vehicle speed sensor 94 when controlling the assist force. Control device 80 can communicate with on-vehicle electronic devices such as EGECU 48 and navigation system 98 via communication line 96 such as CAN. Thereby, control device 80 can obtain the remaining amount of fuel (remaining amount of fuel FR) of internal combustion engine 46 detected by remaining amount sensor 100 via EGECU 48, for example.

  The control device 80 includes a CPU 82, a ROM 84, and a RAM 86. The CPU 82 executes a program stored in the ROM 84 to execute the process of controlling the assist force.

  FIG. 2 shows the procedure of the process related to control of the assist force. The process shown in FIG. 2 is realized by the CPU 82 repeatedly executing the program stored in the ROM 84 at a predetermined cycle. In the following, the step number is represented by a number with "S" added at the beginning.

  In the series of processes shown in FIG. 2, the CPU 82 first obtains the steering angle θ and the vehicle speed SPD, and calculates the steering speed ω based on the steering angle θ (S10). Then, the CPU 82 determines, based on the acquired value, whether an assist is necessary (S12). Here, in the CPU 82, the vehicle speed SPD is less than or equal to the specified speed and the magnitude of the steering speed ω is greater than or equal to the specified speed, and the vehicle speed SPD is higher than the specified speed and the magnitude of the steering angle θ is greater than the specified value. It is determined that the assistance is necessary on the condition that the logical sum of the two is large and true. On the other hand, under the condition that the CPU 82 determines that the logical sum is false, the CPU 82 determines that the assist is not necessary.

  When the CPU 82 determines that the assist is not necessary (S12: NO), the hydraulic control mechanism 50 slightly generates hydraulic fluid to the hydraulic mechanism 20 so that the assist force can be quickly generated when the assist becomes necessary. It is determined that the standby mode is to continue to supply (S14). Then, the CPU 82 selects the standby mode map as a map for setting the discharge flow rate of the hydraulic fluid from the flow control valve 50 to the hydraulic mechanism 20 (S16). The standby mode map is stored in advance in the ROM 84. The map is a set of data of each discrete value of the input variable and the value of the output variable. In the standby mode map according to the present embodiment, the input variable is the vehicle speed SPD and the output variable is the flow rate, but in particular, the flow rate is a constant value regardless of the vehicle speed SPD.

  On the other hand, when it is determined that the assist is necessary (S12: YES), the CPU 82 determines that the assist mode is set (S18). Then, the CPU 82 selects the assist mode map as a map for setting the discharge flow rate of the hydraulic fluid from the flow control valve 50 to the hydraulic mechanism 20 (S20). The assist mode map is stored in advance in the ROM 84. Specifically, in the assist mode map, when the vehicle speed SPD as an input variable is low, the flow rate as an output variable is set to a larger value than when it is high, and the steering speed ω as an input variable is large. Set the flow rate as an output variable to a larger value than when it is smaller.

  When the processing of S16 and S20 is completed, the CPU 82 performs a map operation on the discharge flow rate of hydraulic fluid from the flow control valve 50 to the hydraulic mechanism 20 (S22). In the map operation, for example, when the value of the input variable matches any of the values of the input variable of map data, the value of the output variable of the corresponding map data is taken as the operation result, and when they do not match, a plurality of items included in the map data The value obtained by interpolation of the values of the output variables of may be used as the processing result.

Then, the CPU 82 operates the flow control valve 50 by operating the energizing current of the solenoid 58 so as to obtain the flow obtained by the map calculation (S24).
FIG. 3 shows the procedure for selecting the assist mode map. The process shown in FIG. 3 is realized by the CPU 82 repeatedly executing the program stored in the ROM 84 at a predetermined cycle.

  In the series of processes shown in FIG. 3, the CPU 82 first acquires the remaining amount of fuel FR (S30). Next, the CPU 82 determines whether the remaining fuel amount FR is smaller than a threshold value FRth (S32). This process is to determine whether to reduce the assist rate and reduce the fuel consumption rate. When it is determined that the threshold value is the threshold value FRth or more (S32: NO), the CPU 82 selects a steering priority map as an assist mode map (S34). The steering priority map is a map in which the discharge flow rate to the hydraulic mechanism 20 capable of generating a sufficient assist force for facilitating the operation of the steering 10 is set. On the other hand, when determining that the value is smaller than the threshold value FRth (S32: YES), the CPU 82 selects the fuel efficiency emphasis map as the assist mode map (S36). The fuel efficiency-oriented map is a map for reducing the fuel consumption rate by reducing the discharge flow rate to the hydraulic mechanism 20 as compared with the steering-oriented map. That is, when the magnitudes of the vehicle speed SPD as the input variable and the steering speed ω are the same, the discharge flow rate to the hydraulic mechanism 20 indicated by the fuel efficiency emphasis map is equal to or less than the discharge flow rate indicated by the steering emphasis map. In particular, at least a part of the combination of vehicle speed SPD as an input variable and the magnitude of steering speed ω included in the map data, the discharge flow rate to hydraulic mechanism 20 indicated by the fuel efficiency emphasis map is the discharge flow rate indicated by steering emphasis map It is less than that.

When the processes of S34 and S36 are completed, the CPU 82 temporarily ends the series of processes shown in FIG.
Here, the operation of the present embodiment will be described.

  If the CPU 82 determines that the remaining amount of fuel FR is smaller than the threshold value FRth, in the assist mode, the discharge flow rate from the flow control valve 50 to the hydraulic mechanism 20 is set based on the fuel efficiency priority map, and the flow rate is set based on the set discharge flow rate. The control valve 50 is operated. As a result, the discharge flow rate from the flow control valve 50 to the hydraulic mechanism 20 decreases as compared to the case where the remaining fuel amount FR is smaller than the threshold value FRth. Here, among the hydraulic fluid discharged by the pump 42, the hydraulic fluid flowing out to the hydraulic mechanism 20 via the flow control valve 50 has a pressure loss larger than that of the hydraulic fluid flowing through the short loop passage 29. Therefore, if the discharge flow rate of the hydraulic oil by the pump 42 is the same, the smaller the flow rate of the hydraulic oil flowing out to the hydraulic mechanism 20 through the flow control valve 50, the more necessary for the internal combustion engine 46 to drive the pump 42 Power is reduced. Therefore, the fuel consumption rate of the internal combustion engine 46 is reduced by reducing the discharge flow rate from the flow control valve 50 to the hydraulic mechanism 20. Therefore, by switching to the fuel efficiency emphasis map when the fuel remaining amount FR is small, it is possible to reduce the fuel consumption rate when the fuel remaining amount is small.

Second Embodiment
The second embodiment will be described below with reference to the drawings, focusing on the differences from the first embodiment.

In the present embodiment, in addition to the fuel remaining amount FR, it is determined whether to select the fuel efficiency emphasis map based on the destination information.
FIG. 4 shows a procedure of selection processing of the assist mode map according to the present embodiment. The process shown in FIG. 4 is realized by the CPU 82 repeatedly executing the program stored in the ROM 84 at a predetermined cycle. In FIG. 4, the same step numbers are given to the processing corresponding to the processing shown in FIG. 3 for the sake of convenience.

  In the series of processes shown in FIG. 4, when the fuel remaining amount FR is obtained (S30), the CPU 82 determines whether a destination is inputted to the navigation system 98 (S40). This process is for determining whether the execution condition of the selection process of the fuel efficiency emphasis map and the steering emphasis map based on the destination information is satisfied. Then, when it is determined that there is no input (S40: NO), the CPU 82 executes the same processing of S32 to S36 as the processing shown in FIG.

  On the other hand, when the CPU 82 determines that there is an input of a destination (S40: YES), the CPU 82 acquires a destination (S42). Next, the CPU 82 calculates the predicted fuel consumption amount CF to the destination (S44). Here, the CPU 82 calculates the predicted fuel consumption amount CF to a larger value when the travel distance to the destination is long than when it is short. Specifically, for example, the fuel consumption per unit distance may be determined in advance, and the predicted fuel consumption CF may be calculated by multiplying the amount by the travel distance. Then, the CPU 82 determines whether the remaining fuel amount FR is smaller than a value obtained by adding the margin amount α to the predicted fuel consumption amount CF (S46). In this process, it is determined whether the margin of the remaining fuel amount FR is less than a predetermined value with respect to the amount of fuel necessary for the vehicle to reach the destination.

  When it is determined that the predicted fuel consumption amount CF is equal to or more than the value obtained by adding the margin amount α (S46: NO), the CPU 82 selects the steering priority map as the assist mode map (S36). On the other hand, when it is determined that the CPU 82 is smaller than the value obtained by adding the margin amount α to the predicted fuel consumption amount CF (S46: YES), the CPU 82 selects the fuel efficiency emphasis map as the assist mode map (S34).

When the processes of S34 and S36 are completed, the CPU 82 temporarily ends the series of processes shown in FIG.
Here, the operation of the present embodiment will be described.

  When it is determined that the destination information is input to the navigation system 98, the CPU 82 calculates the predicted fuel consumption amount CF to the destination, and selects the steering emphasis map or the fuel consumption emphasis map based on this calculation Decide. Thus, the CPU 82 selects the fuel efficiency emphasis map when the distance to the destination is long when the fuel remaining amount FR is the same, but adopts the steering importance map when the distance to the destination is short. This makes it possible to increase the adoption frequency of the steering priority map as compared to the case where the destination information is not referred to.

<Correspondence relationship>
Correspondence between the matters in the above-mentioned embodiment and the matters described in the above-mentioned "means for solving the problem" is as follows. Below, correspondence is shown for every number of the solution means described in the column of "Means for solving the problem". [1] The discharge device corresponds to the pump 42 and the flow control valve 50, and the steering control device corresponds to the control device 80. The remaining amount acquisition process corresponds to the process of S30, and the reduction process corresponds to the processes of S32 to S36 of FIG. 3 and the processes of S32 to S36 and S46 of FIG. [2] The “steering operation state” is quantified by the steering speed ω and the steering angle θ, the determination processing corresponds to the processing of S12, S14, and S18, and the increase processing is the processing of S16 and S20. It corresponds. [3] The destination acquisition process corresponds to the process of S42.

<Other Embodiments>
In addition, you may change at least one of each matter of the said embodiment as follows.
・ "About discharge device"
The discharge device is not limited to the one provided with the pump 42 and the flow control valve 50. For example, it may be an electric pump driven by the power of the on-board battery to discharge the hydraulic oil to the hydraulic mechanism 20 and to make the discharge amount variable. In this case, since the amount of work performed by the electric pump increases as compared with the case where the discharge amount of the electric pump is large, the power consumption of the on-board battery by the electric pump is increased. Then, in this case, the amount of power generation of the alternator 46 for converting a part of the driving force of the internal combustion engine 46 into electrical energy increases in order to charge the on-vehicle battery, and the amount of fuel consumption of the internal combustion engine 46 increases. For this reason, reducing the discharge amount of the electric pump as much as possible leads to the reduction of the fuel consumption amount, so it is effective to set the discharge amount in the assist mode in the manner of the above embodiment.

・ "About reduction processing"
In the above embodiment, the discharge flow rate to the hydraulic mechanism 20 is not variably set according to the fuel remaining amount FR in the standby mode, but this may be performed.

  In the first embodiment, the discharge flow rate from the flow control valve 50 to the hydraulic mechanism 20 is switched depending on whether the fuel remaining amount FR is smaller than the threshold value FRth. However, the present invention is not limited thereto. For example, the discharge flow rate may be switched to two or more stages according to the remaining fuel amount FR. This can be realized, for example, by providing three or more types of maps according to the degree of emphasis on fuel consumption.

  In the second embodiment, although the discharge flow rate to the hydraulic mechanism 20 is variably set based on the margin of the remaining fuel amount FR with respect to the predicted fuel consumption amount CF to the destination, the present invention is not limited thereto. For example, even if the fuel supply station is not within a predetermined distance from the travel route to the target value, the discharge flow rate to the hydraulic mechanism 20 can be variably set based on the margin of the remaining fuel amount FR with respect to the predicted fuel consumption CF. Good. In this case, when there is a fueling station within a predetermined distance, the discharge flow rate to the hydraulic mechanism 20 may be variably set based on the margin of the remaining amount of fuel FR with respect to the predicted value of the fuel amount required for traveling to the fueling station.

  When variably setting the discharge flow rate to the hydraulic mechanism 20, the weight of the vehicle may be added. This can be realized, for example, by setting the threshold value FRth to a larger value when the weight of the vehicle is heavy than when the weight is heavy, in the process of S32 of FIG. The weight of the vehicle may be calculated, for example, by adding the basic weight of the vehicle and a value obtained by multiplying the number of seats in which the seating of the person is detected by the seating sensor by a predetermined weight of the person. .

  In addition, a signal indicating whether the driver permits use of the fuel efficiency priority map may be taken in, and processing based on the remaining fuel amount FR may be executed on the condition that the driver is permitted. In this case, if not permitted, the steering emphasis map is used. Here, the signal indicating the intention may be realized by providing the vehicle with a permission switch, or may be realized by receiving the permission signal from the portable terminal of the driver.

・ "About steering control device"
The CPU 82 and the ROM 84 are not limited to the ones that execute software processing. For example, a dedicated hardware circuit (for example, an ASIC or the like) may be provided which performs hardware processing on at least a part of the software processed in the above embodiment. That is, the steering control device may have any one of the following configurations (a) to (c). (A) A processing device that executes all of the above processes in accordance with a program, and a program storage device such as a ROM that stores the program. (B) A processing device and a program storage device that execute part of the above processing according to a program, and a dedicated hardware circuit that performs the remaining processing. (C) A dedicated hardware circuit is provided to execute all of the above processes. Here, the software processing circuit provided with the processing device and the program storage device, and a dedicated hardware circuit may be plural. That is, the above process may be performed by a processing circuit including at least one of one or more software processing circuits and one or more dedicated hardware circuits.

・ About "power steering device"
The power steering apparatus is not limited to one provided with a rack and pinion mechanism.

  DESCRIPTION OF SYMBOLS 10 ... Steering, 12 ... Power steering apparatus, 14 ... Steering wheel, 20 ... Hydraulic mechanism, 22 ... Pinion shaft, 24 ... Rack axis, 25 ... Discharge passage, 26 ... 1st supply / discharge passage, 27 ... 2nd supply / discharge passage , 28: discharge passage, 29: short loop passage, 30: power cylinder, 34: piston, 36: first hydraulic chamber, 38: second hydraulic chamber, 40: switching unit, 42: pump, 44: tank, 46: Internal combustion engine, 48: EGECU, 50: flow control valve, 52: body, 54: spool, 56: spring, 58: solenoid, 60: plunger, 60a: end face, 62: orifice, 64: first chamber, 66: first 2 room 70 spring room 72 bypass passage 80 control device 82 CPU 84 ROM 86 86 RAM 92 steering angle sensor 94 vehicle speed sensor 96 communication line 98 navigation Activation system, 100 ... remaining amount sensor.

Claims (4)

A hydraulic mechanism comprising: a power cylinder; and a switching unit for changing the sign of the assist force output by the power cylinder by switching an oil passage connected to the power cylinder; and discharge for discharging hydraulic fluid to the hydraulic mechanism A power steering device comprising the device;
Remaining amount acquisition processing for acquiring the remaining fuel amount of the vehicle;
A reduction process of operating the discharge device so that the flow rate of the hydraulic fluid discharged by the discharge device to the hydraulic mechanism is smaller than when the remaining amount of fuel acquired by the remaining amount acquisition process is small. Steering control device to execute. A determination process of determining which of an assist mode for generating the assist force and a standby mode for waiting without generating the assist force based on an operation state of steering of the vehicle;
Performing an increasing process of increasing the flow rate of the hydraulic fluid discharged by the discharge device to the hydraulic mechanism in the assist mode than in the standby mode;
The steering control device according to claim 1, wherein the reduction processing is performed on the condition that the assist mode is set. Execute destination acquisition processing for acquiring destination information of the vehicle,
The steering control according to claim 1 or 2, wherein the reduction processing is executed on the condition that a margin of the remaining fuel amount is less than a predetermined value with respect to a fuel amount necessary for the vehicle to reach the destination. apparatus. The discharge device adjusts an amount of an engine drive type pump driven by a vehicle-mounted internal combustion engine and an amount of the hydraulic fluid discharged by the pump, which is returned to the upstream side of the pump without being discharged to the hydraulic mechanism. And a flow control valve,
The steering according to any one of claims 1 to 3, wherein the reduction process is a process of controlling the flow rate of the hydraulic oil discharged from the discharge device to the hydraulic mechanism by operating the flow control valve. Control device.