JP2013119269A - Vehicular control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular control device which secures a necessary brake negative pressure and appropriately controls the drive of an auxiliary machine driven by an internal combustion engine.SOLUTION: The vehicular control device 10 is applied to a vehicle 12 provided with an air conditioner 18 driven by the internal combustion engine 14 and a brake booster 30, which increases the braking force of a brake utilizing the intake pressure of the internal combustion engine 14. The vehicular control device 10 includes: an atmospheric pressure sensor 64, which obtains an atmospheric pressure; a negative pressure sensor 66, which obtains the negative pressure in the brake booster 30; a negative pressure threshold value setting part 82, which sets a negative pressure threshold value ΔP0 smaller as the atmospheric pressure obtained by the atmospheric pressure sensor 64 is lower; and an air conditioner drive controlling part 86, which stops or limits the drive of the air conditioner 18 based on a negative pressure ΔP obtained by the negative pressure sensor and the negative pressure threshold value ΔP0 set by the negative pressure threshold value setting part 82.

Description

  The present invention relates to a vehicle control device applied to a vehicle including an auxiliary machine driven by an internal combustion engine and a brake booster that increases a braking force of a brake using intake pressure of the internal combustion engine.

  2. Description of the Related Art Conventionally, vehicles equipped with a brake booster (vacuum braking booster) that increases the braking force of a brake by using the intake pressure of an internal combustion engine have been widely used. The brake booster generally has a housing that is partitioned into a variable pressure chamber and a negative pressure chamber by a diaphragm, and in a state where no brake operation is performed by a driver, the variable pressure chamber is an internal combustion engine. It communicates with the negative pressure chamber where the intake air is guided. When the driver performs a brake operation, communication between the negative pressure chamber and the variable pressure chamber is interrupted, and air outside the vehicle (atmosphere) is guided into the variable pressure chamber, whereby the negative pressure chamber and the variable pressure chamber are guided. A pressure difference (brake negative pressure) is generated between the chamber and the brake negative pressure assists the driver's brake operation force.

  In this type of brake booster, when an auxiliary machine such as an air conditioner mounted on a vehicle is driven by an internal combustion engine, the load on the internal combustion engine increases and the opening of the throttle valve increases. Pressure increases. If it does so, it will become difficult to ensure required brake negative pressure.

  As a method for securing a required brake negative pressure in a vehicle equipped with an air conditioner driven by an internal combustion engine, a negative pressure switch is provided in a communication path connecting an intake passage of the internal combustion engine and a brake booster. A technical idea is known in which, when it is detected that the negative pressure in the communication path is equal to or lower than a predetermined value, the driving of the air conditioner is stopped for a certain period of time (for example, see Patent Document 1).

JP 2003-104046 A

  As described above, since the brake negative pressure is a differential pressure between the variable pressure chamber and the negative pressure chamber, it changes according to the height of the atmospheric pressure guided into the variable pressure chamber. Therefore, for example, the higher the altitude of the place where the vehicle is traveling or stopped, the lower the pressure in the transformer chamber (the brake negative pressure becomes smaller), and the lower the elevation, the higher the pressure in the transformer chamber (brake Negative pressure increases).

  Then, as in the conventional technique such as Patent Document 1 described above, when determining whether to stop driving the air conditioner based on one negative pressure threshold related to ON / OFF of the negative pressure switch, The frequency of stopping the driving of the air conditioner is increased or decreased according to the change in the atmospheric pressure. If the driving of the air conditioner is frequently stopped, for example, there may be a disadvantage that fogging of the windshield of the vehicle cannot be eliminated by the air conditioner.

  The present invention has been made in consideration of such a problem, and can be used for a vehicle capable of ensuring necessary brake negative pressure and appropriately controlling driving of an auxiliary machine driven by an internal combustion engine. An object is to provide a control device.

[1] A vehicle control device according to the present invention is applied to a vehicle including an auxiliary machine driven by an internal combustion engine and a brake booster that increases a braking force of a brake by using intake pressure of the internal combustion engine. In the vehicle control device, an atmospheric pressure acquisition means for acquiring an atmospheric pressure, a negative pressure acquisition means for acquiring a negative pressure in the brake booster, and a negative pressure based on the atmospheric pressure acquired by the atmospheric pressure acquisition means Stop driving of the auxiliary machine based on the negative pressure threshold setting means for setting the threshold, the negative pressure acquired by the negative pressure acquisition means and the negative pressure threshold set by the negative pressure threshold setting means, or And auxiliary device drive control means for limiting.

  Here, the negative pressure acquired by the negative pressure acquisition means may be a differential pressure between the absolute pressure of the atmospheric pressure and the absolute pressure of the intake air introduced into the brake booster, or the absolute pressure of the intake air. Also good.

  According to the vehicle control device of the present invention, the auxiliary machine drive control means stops or restricts the driving of the auxiliary machine based on the negative pressure in the brake booster and the negative pressure threshold value, thereby reducing the load on the internal combustion engine. Thus, the opening of the throttle valve can be reduced (the intake air amount of the internal combustion engine can be reduced). Thereby, a required brake negative pressure is securable.

  Moreover, since the negative pressure threshold value setting means for setting the negative pressure threshold value based on the atmospheric pressure acquired by the atmospheric pressure acquisition means is provided, the driving of the auxiliary machine is stopped or restricted depending on the height of the atmospheric pressure. It is possible to suppress the variation in the frequency of being performed. In other words, for example, even when the atmospheric pressure is relatively low (when the altitude of the place where the vehicle is traveling or stopped is high), the driving of the auxiliary machine is prevented from being stopped or restricted more than necessary. can do. Thereby, when the auxiliary machine is an air conditioner, it becomes possible to eliminate fogging of the windshield of the vehicle by the air conditioner. Therefore, it is possible to appropriately control the driving of the auxiliary machine driven by the internal combustion engine.

[2] In the above vehicle control device, the negative pressure acquisition means acquires, as a negative pressure, an absolute value of a differential pressure between the absolute pressure of the atmospheric pressure and the absolute pressure of the intake air introduced into the brake booster, The negative pressure threshold setting means sets the negative pressure threshold to be smaller as the atmospheric pressure acquired by the atmospheric pressure acquisition means is lower, and the accessory drive control means is acquired by the negative pressure acquisition means. When the negative pressure is smaller than the negative pressure threshold set by the negative pressure threshold setting means, the driving of the auxiliary machine may be stopped or limited.

  According to such a device, the absolute value of the differential pressure between the absolute pressure of the atmospheric pressure and the absolute pressure of the intake air introduced into the brake booster is acquired as a negative pressure, and the atmospheric pressure acquired by the atmospheric pressure acquisition means The lower the negative pressure threshold is, the smaller the negative pressure threshold is set, and when the negative pressure is smaller than the negative pressure threshold, the driving of the auxiliary machine is stopped or limited. Therefore, driving the auxiliary machine while ensuring the minimum necessary brake negative pressure Can be reduced as much as possible. Thereby, the drive of the auxiliary machine driven by the internal combustion engine can be controlled more appropriately.

[3] In the above vehicle control device, the negative pressure threshold setting means sets the negative pressure threshold when the vehicle is in a creep running state to be greater than the negative pressure threshold when the vehicle is in a stopped state. You may set large.

  According to such a device, since the negative pressure threshold value when the vehicle is in the creep running state is set to be larger than the negative pressure threshold value when the vehicle is in the stopped state, it is necessary in the creep running state in which the brake operation is relatively performed. It is possible to ensure a sufficient brake negative pressure. As a result, safety during creeping of the vehicle can be enhanced.

[4] In the above vehicle control device, the vehicle control device further includes a road surface gradient acquisition unit that acquires a gradient of a road surface on which the vehicle is traveling or stopped, and the negative pressure threshold setting unit is acquired by the road surface gradient acquisition unit. The negative pressure threshold may be set larger as the slope of the road surface is larger.

  For example, when the vehicle stops on a road surface with a relatively large gradient, the necessary brake braking force (brake negative pressure) becomes larger than when the vehicle stops on a road surface with a small gradient. According to the above vehicle control device, the negative pressure threshold value is set to be larger as the road surface gradient is larger. Therefore, even when the road surface on which the vehicle is traveling or stopped is large, the driving of the auxiliary machine is stopped. Alternatively, the necessary brake negative pressure can be reliably ensured by limiting.

[5] The vehicle control device further includes a brake operation force acquisition unit that acquires an operation force input to the brake operation unit, and the negative pressure threshold setting unit is acquired by the brake operation force acquisition unit. The negative pressure threshold value may be set larger as the brake operation force increases.

  Normally, when the brake operation force input to the brake operation unit increases to a predetermined value, the brake booster reaches the assist limit (boost limit) because the pressure in the variable pressure chamber increases to atmospheric pressure. After reaching the assist limit, the driver cannot assist the driver's braking force. Here, the magnitude of the brake operation force reaching the assist limit is determined by the relationship with the brake negative pressure, and increases as the brake negative pressure increases.

  According to the above vehicle control device, the larger the brake operation force, the larger the negative pressure threshold value is set. Therefore, even when the brake operation force is large, the necessary brake negative pressure is ensured to ensure the brake operation force. Can help.

[6] In the above vehicle control apparatus, the vehicle control device further includes a cooling water temperature acquisition unit that acquires a temperature of cooling water for cooling the internal combustion engine, and the negative pressure threshold setting unit is acquired by the cooling water temperature acquisition unit. The negative pressure threshold value when the measured temperature is equal to or lower than a predetermined temperature may be set larger than the negative pressure threshold value when the temperature acquired by the cooling water temperature acquisition means is higher than the predetermined temperature. .

  In a vehicle equipped with an electronically controlled throttle (drive-by-wire), when the temperature of the cooling water for cooling the internal combustion engine is low, the throttle opening is increased in order to warm up the internal combustion engine. As a result, the brake negative pressure may be insufficient.

  According to the above-described vehicle control device, the negative pressure threshold when the temperature of the cooling water for cooling the internal combustion engine is equal to or lower than the predetermined value is set lower than the negative pressure threshold when the temperature of the cooling water is higher than the predetermined temperature. Therefore, the required brake negative pressure can be ensured even when the internal combustion engine is warmed up.

[7] In the above vehicle control device, accelerator pedal operation detecting means for detecting whether or not the accelerator pedal is operated, shift position detecting means for detecting the shift position of the transmission, and vehicle speed detecting means for detecting the vehicle speed. And the accessory drive control means is configured such that when the accelerator pedal is not operated, the shift position of the transmission is in the forward position or the reverse position, and the vehicle speed is equal to or lower than a predetermined value. The driving of the auxiliary machine may be stopped or restricted.

  According to such a device, in a vehicle state where it is necessary to ensure the brake assist force, it is possible to reliably ensure the necessary brake negative pressure by stopping or controlling the driving of the auxiliary machine.

[8] In the above vehicle control device, when the internal combustion engine is stopped while the vehicle is stopped, based on the negative pressure acquired by the negative pressure acquisition means and the negative pressure threshold, Restarting means for automatically restarting the internal combustion engine may be provided.

  According to such a device, when the internal combustion engine is stopped (idling stop, no idling) while the vehicle is stopped, based on the negative pressure and the negative pressure threshold acquired by the negative pressure acquisition means. Restarting means for automatically restarting the internal combustion engine is provided. Even in such a case, since the negative pressure threshold value is set by the negative pressure threshold value setting means, unnecessary restart of the internal combustion engine can be prevented. Thereby, the fuel consumption can be improved.

  As described above, according to the present invention, the negative pressure threshold value is set based on the atmospheric pressure acquired by the atmospheric pressure acquisition means, and the auxiliary machine is set based on the negative pressure in the brake booster and the negative pressure threshold value. Therefore, the necessary brake negative pressure can be ensured and the auxiliary machine driven by the internal combustion engine can be appropriately controlled.

It is a mimetic diagram of a vehicle carrying a vehicle control device concerning one embodiment of the present invention. It is explanatory drawing of the 1st map which shows an example of the relationship between atmospheric pressure and negative pressure threshold value (DELTA) P1. 3 is a flowchart for explaining the operation of the vehicle control device shown in FIG. 1. It is a flowchart which shows the subroutine of step S5 of the flowchart shown in FIG. It is explanatory drawing of the 2nd map which shows an example of the relationship between a vehicle state and negative pressure threshold value (DELTA) P2. It is explanatory drawing of the 3rd map which shows an example of the relationship between a road surface gradient and negative pressure threshold value (DELTA) P3. It is explanatory drawing of the 4th map which shows an example of the relationship between brake operation force and negative pressure threshold value (DELTA) P4. FIG. 8A is an explanatory diagram of a fifth map showing an example of the relationship between the cooling water temperature T and the negative pressure threshold ΔP5, and FIG. 8B is an explanatory diagram showing another example of the fifth map.

  Hereinafter, a preferred embodiment of a vehicle control device according to the present invention will be exemplified and described with reference to the accompanying drawings.

  First, a vehicle 12 equipped with a vehicle control device 10 according to an embodiment of the present invention will be described.

  The vehicle 12 includes an internal combustion engine 14, a brake device 16 for decelerating or stopping the vehicle 12, an air conditioner (auxiliary device) 18 that adjusts the temperature or the like of a vehicle interior (not shown), and the vehicle control device 10. .

  The internal combustion engine 14 includes an internal combustion engine body 20, an intake passage 22 that guides intake air to the internal combustion engine body 20, and an exhaust passage 24 that guides exhaust gas from the internal combustion engine body 20. A throttle valve 26 is provided in the intake passage 22 for adjusting the flow rate of intake air that is guided to the internal combustion engine body 20. The throttle valve 26 is configured as an electronically controlled throttle (drive-by-wire).

  The brake device 16 includes a brake pedal (brake operation unit) 28 that can be operated by the driver, a brake booster (vacuum servo) 30 provided in the brake pedal 28, and a linkage that guides intake air in the intake passage 22 to the brake booster 30. A passage 32, a master cylinder 36 provided in the brake booster 30 and containing a piston 34, a brake member 38 provided in each wheel of the vehicle 12, and a brake pipe connecting the master cylinder 36 and each brake member 38 40. In FIG. 1, only the brake member 38 provided on each front wheel of the vehicle 12 is shown, and the brake member 38 provided on each rear wheel is omitted.

  The brake booster 30 is configured as a so-called vacuum braking booster, and assists the driver's brake operation force (depressing force of the brake pedal 28) and transmits it to the piston 34 in the master cylinder 36.

  The brake booster 30 includes a housing 42, a hub 44 provided in the housing 42, a diaphragm 46 fixed to the hub 44, and a push rod that protrudes from the hub 44 and can press the end surface of the piston 34 in the master cylinder 36. 48.

  The inside of the housing 42 is partitioned into a variable pressure chamber 50 and a negative pressure chamber 52 by a diaphragm 46 that can slide inside the housing 42. The housing 42 is provided with an air introduction port 54 that guides air outside the vehicle (atmosphere) into the variable pressure chamber 50. The intake air in the intake passage 22 is guided into the negative pressure chamber 52 through the communication passage 32.

  The hub 44 is configured to be movable along the axial direction in the housing 42 in a state of being provided integrally with the diaphragm 46 and the push rod 48. Although detailed illustration is omitted, the hub 44 communicates with the inside of the variable pressure chamber 50 and the inside of the negative pressure chamber 52 in a state where the brake pedal 28 is not operated, and the variable pressure chamber 50 when the brake pedal 28 is operated. A valve mechanism is provided so that communication between the inside and the negative pressure chamber 52 is blocked, and the atmosphere is introduced into the variable pressure chamber 50 from the atmosphere introduction port 54. The diaphragm 46 is urged toward the variable pressure chamber 50 by a compression coil spring (not shown).

  The communication passage 32 is provided with a check valve 56 that permits the flow of intake air from the intake passage 22 into the negative pressure chamber 52 while preventing the flow of air from the negative pressure chamber 52 into the intake passage 22. It has been.

  The master cylinder 36 and the brake pipe 40 are filled with hydraulic fluid (brake fluid). Each brake member 38 is configured as a disc brake, for example, and includes a brake rotor 58 that can rotate integrally with a wheel, and a brake pad 60 that can contact the brake rotor 58. The brake pad 60 contacts the brake rotor 58 when pressure is applied to the hydraulic oil by the piston 34.

  In the brake device 16 configured as described above, when the driver operates the brake pedal 28, the communication between the inside of the variable pressure chamber 50 and the inside of the negative pressure chamber 52 is blocked and the atmosphere is guided into the variable pressure chamber 50. A pressure difference (brake negative pressure) occurs between the variable pressure chamber 50 and the negative pressure chamber 52. Then, the brake operation force assisted by the brake negative pressure is transmitted to the piston 34 via the push rod 48, so that the piston 34 is displaced in the master cylinder 36. When the hydraulic oil is pressurized due to the displacement of the piston 34, the brake pad 60 comes into contact with (being pressed against) the brake rotor 58 to generate a frictional force, so that the rotation of the wheels is suppressed and the vehicle 12 decelerates. To be done.

  On the other hand, in a state where the brake pedal 28 is not operated, the inside of the variable pressure chamber 50 and the inside of the negative pressure chamber 52 are communicated to have the same pressure, so that the push rod 48 does not pressurize the piston 34. Therefore, the braking force does not act on the vehicle 12.

  The vehicle control device 10 includes various sensors and a control unit 62. As various sensors, for example, an atmospheric pressure sensor 64, a negative pressure sensor 66, a water temperature sensor 68, a brake sensor 70, an accelerator sensor 72, a shift position sensor 74, a vehicle speed sensor 76, a road surface gradient sensor 78, and the like are used. Detection signals from various sensors are output to the control unit 62.

  The atmospheric pressure sensor 64 detects an absolute pressure P1 of atmospheric pressure. The negative pressure sensor 66 is provided in the communication passage 32 on the downstream side (negative pressure chamber 52 side) of the check valve 56, and detects the absolute pressure P2 in the communication passage 32 (negative pressure chamber 52).

  The water temperature sensor 68 detects the temperature T of cooling water flowing through a water jacket (not shown) formed in the internal combustion engine body 20. A brake sensor (brake operating force acquisition means) 70 is provided on the brake pedal 28 and detects an operating force (stepping force) of the brake pedal 28. Note that the brake sensor 70 may detect the stroke amount (operation amount) of the brake pedal 28 instead of directly detecting the operation force of the brake pedal 28.

  The accelerator sensor 72 detects a stroke amount (operation amount) of an accelerator pedal (not shown). The shift position sensor 74 detects a shift position of a transmission (not shown). For example, the shift position sensor 74 detects a shift position (parking position P, forward position D, neutral position N, reverse position R) of a shift lever (not shown). .

  The vehicle speed sensor 76 detects the speed of the vehicle 12. The road surface gradient sensor 78 detects the gradient of the road surface on which the vehicle 12 is traveling or stopped. In addition, it is good also as the said road surface gradient sensor by providing an acceleration sensor in the front part and rear part of the vehicle 12, and detecting the inclination degree of the vehicle 12 by these acceleration sensors. Further, the road surface gradient sensor can be configured to detect the road surface gradient based on the map information or the like stored in the navigation device mounted on the vehicle 12 and the GPS position information.

  The control unit 62 includes a negative pressure calculation unit 80, a negative pressure threshold setting unit 82, a negative pressure determination unit 84, an air conditioner drive control unit 86, an internal combustion engine drive control unit 88, and a storage unit 90.

  The negative pressure calculation unit 80 calculates the negative pressure ΔP in the brake booster 30. Here, the negative pressure ΔP is the absolute value of the differential pressure between the absolute pressure P1 of atmospheric pressure and the absolute pressure P2 in the negative pressure chamber 52 (ΔP = | P1-P2 |).

  The negative pressure threshold setting unit 82 sets the negative pressure threshold ΔP0 based on output signals of various sensors and a first map described later stored in the storage unit 90.

  The negative pressure determination unit 84 determines whether or not the negative pressure ΔP calculated by the negative pressure calculation unit 80 is smaller than the negative pressure threshold ΔP0 set by the negative pressure threshold setting unit 82. The air conditioner drive control unit 86 controls driving of the air conditioner 18 based on the determination result of the negative pressure determination unit 84.

  The internal combustion engine drive control unit 88 controls the opening degree of the throttle valve 26 based on output signals from various sensors. That is, the internal combustion engine drive control unit 88 increases the opening of the throttle valve 26 when the temperature T of the cooling water for cooling the internal combustion engine body 20 is lower than a predetermined temperature (a set water temperature value T0 described later), The internal combustion engine body 20 is warmed up.

  The internal combustion engine drive control unit 88 also includes an internal combustion engine automatic stop (idling stop, no idling) function that stops driving the internal combustion engine 14 when a predetermined condition is satisfied while the vehicle is stopped, and a negative pressure determination unit 84. An internal combustion engine restarting function for restarting the automatic stop of the internal combustion engine based on the determination result;

  The storage unit 90 stores a set vehicle speed value V0, a set water temperature value T0, and a first map. The set vehicle speed value V0 is set to an arbitrary value larger than the vehicle speed value in the creep travel state, for example. The set water temperature value T0 is set, for example, to the temperature of the cooling water flowing through the water jacket of the internal combustion engine body 20 when the internal combustion engine 14 is warmed up.

  As shown in FIG. 2, the first map shows the relationship between the atmospheric pressure and the negative pressure threshold ΔP1, and is set such that the lower the atmospheric pressure, the smaller the negative pressure threshold ΔP1. In the first map, a negative pressure lower limit threshold value ΔP1a and a negative pressure upper limit threshold value ΔP1b are defined. For example, the negative pressure lower limit threshold ΔP1a can be set to a value corresponding to the brake negative pressure that can assist the driver's brake operation force. For example, the negative pressure upper limit threshold ΔP1b can be set to a value that does not frequently cause the air conditioner 18 to stop driving.

  Next, the operation of the vehicle control device 10 according to the present embodiment will be described with reference to FIGS. Note that the flowchart shown in FIG. 3 is repeatedly executed at a predetermined cycle.

  First, the control unit 62 determines whether or not the air conditioner 18 is driven by the internal combustion engine 14 (step S1 in FIG. 3). If it is determined that the air conditioner 18 is not being driven (step S1: NO), the current main routine processing is terminated.

  If it is determined that the air conditioner 18 is being driven (step S1: YES), the control unit 62 determines whether or not the accelerator pedal is being operated (step S2). This determination process is determined based on the stroke amount of the accelerator pedal detected by the accelerator sensor 72. If it is determined that the accelerator pedal is being operated (step S2: YES), the current main routine processing is terminated.

  When it is determined that the accelerator pedal is not operated (step S2: NO), the control unit 62 determines whether the shift position is at the forward position D or the reverse position R (step S3). In this determination process, the shift position detected by the shift position sensor 74 is used. When the shift position is the parking position P or the neutral position N (step S3: NO), the current main routine processing is terminated.

  When the shift position is the forward position D or the reverse position R (step S3: YES), the control unit 62 determines whether or not the vehicle speed is equal to or less than the set vehicle speed value V0 (predetermined value) (step S4). In this determination process, the vehicle speed detected by the vehicle speed sensor 76 is used. The set vehicle speed value V0 is acquired with reference to the storage unit 90. If the vehicle speed is greater than the set vehicle speed value V0 (step S4: NO), the current main routine processing is terminated.

  If the vehicle speed is less than or equal to the set vehicle speed value V0, the negative pressure threshold setting unit 82 sets the negative pressure threshold ΔP0 (step S5). The negative pressure threshold ΔP0 is set by executing the flowchart shown in FIG. Specifically, first, the control unit 62 acquires the absolute pressure P1 of atmospheric pressure (step S20 in FIG. 4). The atmospheric pressure absolute pressure P <b> 1 is detected by the atmospheric pressure sensor 64.

  Subsequently, the negative pressure threshold setting unit 82 sets the negative pressure threshold ΔP1 based on the absolute pressure P1 of atmospheric pressure and the first map (see step S21, FIG. 2). The first map is acquired with reference to the storage unit 90. As a result, the negative pressure threshold ΔP1 is set smaller as the absolute pressure P1 of atmospheric pressure is lower.

  Next, the negative pressure threshold setting unit 82 creates a second map based on the negative pressure threshold ΔP1 set in step S21 (see step S22, FIG. 5). The second map shows the relationship between the vehicle state (stop state, low speed travel state, creep travel state, etc.) and the negative pressure threshold value ΔP2, and the negative pressure threshold value ΔP2b in the creep travel state is the negative pressure threshold value ΔP2a in the stop state. Created to be larger than.

  Thereafter, the control unit 62 acquires the vehicle state (step S23). The vehicle state refers to a stopped state, a low-speed traveling state, a creep traveling state, or the like. The stop state can be determined based on the output signal of the vehicle speed sensor 76. The low-speed traveling state is a vehicle traveling state at a speed lower than the vehicle traveling speed in the creep traveling state, and can be determined based on output signals of the vehicle speed sensor 76, the accelerator sensor 72, and the brake sensor 70. The creep running state can be determined based on the output signals of the vehicle speed sensor 76 and the accelerator sensor 72.

  And the negative pressure threshold value setting part 82 sets negative pressure threshold value (DELTA) P2 based on a 2nd map and a vehicle state (step S24). Thus, for example, the negative pressure threshold value ΔP2 is set to a negative pressure threshold value ΔP2a when the vehicle is stopped, and is set to a value that is greater than or equal to the negative pressure threshold value ΔP2a and smaller than the negative pressure threshold value ΔP2b when the vehicle is traveling at low speed. If there is, the negative pressure threshold value ΔP2b is set (see FIG. 5).

  Subsequently, the negative pressure threshold value setting unit 82 creates a third map based on the negative pressure threshold value ΔP2 (see step S25, FIG. 6). The third map shows the relationship between the road surface gradient and the negative pressure threshold value ΔP3, and is created such that the negative pressure threshold value ΔP3 increases as the road surface gradient increases.

  Next, the controller 62 acquires a road surface gradient (step S26). The road surface gradient is detected by a road surface gradient sensor 78.

  Thereafter, the negative pressure threshold setting unit 82 sets the negative pressure threshold ΔP3 based on the third map and the road surface gradient (step S27). Thereby, the negative pressure threshold ΔP3 is set to be larger as the road surface gradient is larger (as the inclination angle of the road surface on which the vehicle 12 is stopped or traveling is larger) (see FIG. 6).

  And the negative pressure threshold value setting part 82 produces a 4th map based on negative pressure threshold value (DELTA) P3 (refer step S28 and FIG. 7). The fourth map shows the relationship between the brake operation force input to the brake pedal 28 and the negative pressure threshold ΔP4, and is created such that the negative pressure threshold ΔP4 increases as the brake operation force increases.

  Subsequently, the control unit 62 acquires the brake operation force input to the brake pedal 28 (step S29). As the brake operation force, the brake operation force detected by the brake sensor 70 is used.

  Next, the negative pressure threshold value setting unit 82 sets the negative pressure threshold value ΔP4 based on the fourth map and the brake operation force (step S30). Thereby, the negative pressure threshold value ΔP4 is set to be larger as the brake operation force is larger (see FIG. 7).

  Thereafter, the negative pressure threshold setting unit 82 creates a fifth map based on the negative pressure threshold ΔP4 (step S31, FIG. 8A and FIG. 8B). The fifth map shows the relationship between the temperature T of the cooling water flowing through the water jacket of the internal combustion engine body 20 and the negative pressure threshold ΔP5, and the temperature T is equal to or lower than a set water temperature value T0 (predetermined temperature). The negative pressure threshold value ΔP5b in this case is created so as to be larger than the negative pressure threshold value ΔP5a in the case where the temperature is higher than the set water temperature value T0. Here, the set water temperature value T0 is acquired with reference to the storage unit 90.

  For example, the fifth map may be created so that the negative pressure threshold ΔP5a and the negative pressure threshold ΔP5b are switched at the set water temperature value T0 (see FIG. 8A). For example, the temperature T is the set water temperature value. When the temperature T is equal to or lower than T0, the temperature T may be gradually decreased (or stepwise) as the temperature T increases (FIG. 8B).

  And the control part 62 acquires the temperature T of the cooling water which distribute | circulates the said water jacket of the internal combustion engine main body 20 (step S32). As the temperature T of the cooling water, the temperature detected by the water temperature sensor 68 is used.

  Subsequently, the negative pressure threshold setting unit 82 sets the negative pressure threshold ΔP5 based on the fifth map and the temperature T of the cooling water (step S33). Thereby, when the temperature T of the cooling water is equal to or lower than the set water temperature value T0, the negative pressure threshold value ΔP5 is set to be larger than the negative pressure threshold value ΔP5a when it is higher than the set water temperature value T0 (FIGS. 8A and 8B). reference).

  Next, the negative pressure threshold setting unit 82 sets the negative pressure threshold ΔP5 as the negative pressure threshold ΔP0 (step S34). At this stage, the flowchart for setting the negative pressure threshold ΔP0 is completed, and then the process of step S6 in the flowchart of FIG. 3 is performed.

  In step S <b> 6, the control unit 62 acquires the negative pressure ΔP in the brake booster 30. Specifically, the negative pressure calculation unit 80 calculates the absolute value (ΔP = | P1−P2 |) of the differential pressure between the absolute pressure P1 of atmospheric pressure and the absolute pressure P2 in the negative pressure chamber 52. The absolute pressure P1 of the atmospheric pressure is detected by the atmospheric pressure sensor, and the absolute pressure P2 in the negative pressure chamber 52 is detected by the negative pressure sensor 66.

  Next, the negative pressure determination unit 84 determines whether or not the negative pressure ΔP in the brake booster 30 is smaller than the negative pressure threshold value ΔP0 (step S7). If the negative pressure ΔP is greater than or equal to the negative pressure threshold ΔP0 (step S7: NO), the process of the current flowchart is terminated. This is because the negative pressure ΔP in the brake booster 30 is secured to such an extent that the brake operating force can be sufficiently assisted, and there is no possibility of insufficient brake negative pressure.

  When the negative pressure ΔP is smaller than the negative pressure threshold ΔP0 (step S7: YES), the air conditioner drive control unit 86 stops or restricts the driving of the air conditioner 18 (step S8). As a result, the load on the internal combustion engine 14 is reduced and the opening of the throttle valve 26 is reduced, so that the absolute pressure P2 in the negative pressure chamber 52 of the brake booster 30 is reduced. Thereby, a required brake negative pressure is securable. The air conditioner drive control unit 86 may automatically drive the air conditioner 18 in a normal operation after a predetermined time has elapsed for the air conditioner 18 whose drive has been stopped or restricted.

  Subsequently, the control unit 62 determines whether or not the internal combustion engine 14 is automatically stopped (step S9). If the internal combustion engine 14 is not automatically stopped, the current main routine processing is terminated. If the internal combustion engine 14 is automatically stopped, the internal combustion engine drive control unit 88 restarts the internal combustion engine 14 (step S10). Thereafter, the processing of the current main routine is terminated.

  According to the present embodiment, when the negative pressure ΔP in the brake booster 30 is smaller than the negative pressure threshold value ΔP0, the air conditioner drive control unit 86 stops or restricts the driving of the air conditioner 18, thereby reducing the load on the internal combustion engine 14. Thus, the opening degree of the throttle valve 26 can be reduced (the intake air amount of the internal combustion engine body 20 can be reduced). As a result, the necessary brake negative pressure can be ensured even when the brake negative pressure may be insufficient.

  Further, the negative pressure threshold setting unit 82 sets the negative pressure threshold ΔP1 based on the absolute pressure P1 of atmospheric pressure and the first map, and sets the negative pressure threshold ΔP0 based on the negative pressure threshold ΔP1. Since the negative pressure threshold ΔP0 is set smaller as the absolute pressure P1 of the atmospheric pressure is lower, the frequency at which the drive of the air conditioner 18 is stopped or restricted is minimized while ensuring the minimum necessary brake negative pressure. Can do.

  Thereby, for example, even when the atmospheric pressure is relatively low (the altitude of the place where the vehicle 12 is traveling or stopped is high), the air conditioner 18 can be prevented from being stopped or restricted more than necessary. Therefore, the fog of the windshield of the vehicle 12 can be reliably eliminated by the air conditioner 18. Accordingly, the necessary brake negative pressure can be ensured and the drive of the air conditioner 18 driven by the internal combustion engine 14 can be appropriately controlled.

  According to the present embodiment, the negative pressure threshold setting unit 82 sets the negative pressure threshold ΔP2 based on the second map created based on the negative pressure threshold ΔP1 and the vehicle state, and based on the negative pressure threshold ΔP2. By setting the negative pressure threshold value ΔP0, the negative pressure threshold value ΔP0 when the vehicle 12 is in the creep running state is set larger than the negative pressure threshold value ΔP0 when the vehicle 12 is in the stopped state.

  As a result, the necessary brake negative pressure can be reliably ensured in a creep running state in which a relatively large number of brake operations are performed. Therefore, safety during creep traveling of the vehicle 12 can be enhanced.

  By the way, for example, when the vehicle 12 stops on a road surface with a relatively large gradient, the required braking force of the brake becomes larger than when the vehicle 12 stops on a road surface with a small gradient.

  In the present embodiment, the negative pressure threshold setting unit 82 sets the negative pressure threshold ΔP3 based on the third map created based on the negative pressure threshold ΔP2 and the road gradient, and the negative pressure based on the negative pressure threshold ΔP3. By setting the threshold value ΔP0, the negative pressure threshold value ΔP0 is set larger as the road surface gradient increases. As a result, even when the road surface gradient where the vehicle 12 is traveling or stopped is large, the driving of the air conditioner 18 can be stopped or restricted to ensure the necessary brake negative pressure.

  When the brake operation force input to the brake pedal 28 increases to a predetermined value, the brake booster 30 reaches the assist limit (boost limit) because the pressure in the variable pressure chamber 50 increases to atmospheric pressure. After reaching the assist limit, the driver cannot assist the driver's braking force. Here, the magnitude of the brake operation force reaching the assist limit is determined by the relationship with the brake negative pressure, and increases as the brake negative pressure increases.

  In the present embodiment, the negative pressure threshold setting unit 82 sets the negative pressure threshold ΔP4 based on the fourth map created based on the negative pressure threshold ΔP3 and the brake operation force, and the negative pressure threshold ΔP4 is set based on the negative pressure threshold ΔP4. By setting the pressure threshold value ΔP0, the negative pressure threshold value ΔP0 is set to increase as the brake operation force increases. Thereby, even when the brake operation force is large, it is possible to ensure the necessary brake negative pressure and reliably assist the brake operation force.

  Further, the negative pressure threshold setting unit 82 sets the negative pressure threshold ΔP5 based on the fifth map created based on the negative pressure threshold ΔP4 and the temperature T of the cooling water for cooling the internal combustion engine 14, and the negative pressure threshold When the cooling water temperature T is higher than the set water temperature value T0 by setting the negative pressure threshold value ΔP0 based on ΔP5, so that the cooling water temperature T is lower than the set water temperature value T0. Is set to be greater than the negative pressure threshold ΔP0.

  As a result, even when the temperature T of the cooling water for cooling the internal combustion engine 14 is lower than the set water temperature value T0 and the opening degree of the throttle valve 26 is increased to warm up the internal combustion engine 14, the necessary brake negative Pressure can be secured.

  In the present embodiment, when the negative pressure ΔP in the brake booster 30 is smaller than the negative pressure threshold ΔP0 set by the negative pressure threshold setting unit 82 and the internal combustion engine 14 is automatically stopped, the internal combustion engine 14 is Restart. Even in such a case, since the negative pressure threshold value setting unit 82 sets the negative pressure threshold value ΔP0, unnecessary restart of the internal combustion engine 14 can be prevented. Thereby, the fuel consumption can be improved.

  The present invention is not limited to the above-described embodiment, and it is naturally possible to adopt various configurations without departing from the gist of the present invention.

  For example, in the vehicle control apparatus 10 according to the present invention, the negative pressure threshold setting unit 82 may set the negative pressure threshold ΔP1 as the negative pressure threshold ΔP0 without setting the negative pressure thresholds ΔP2 to ΔP5, for example. . In this case, since the processing from step S22 to step S33 can be omitted, the time required to set the negative pressure threshold ΔP0 can be shortened.

  Further, the negative pressure threshold value setting unit 82 may omit at least one of the setting processes of the negative pressure threshold values ΔP2 to ΔP5. For example, when only the setting process of the negative pressure threshold ΔP2 is omitted, the negative pressure threshold setting unit 82 creates a third map based on the negative pressure threshold ΔP1, and based on the third map and the road surface gradient. The negative pressure threshold ΔP3 may be set.

  In the vehicle control device 10 according to the present invention, the auxiliary machine driven by the internal combustion engine 14 is not limited to the air conditioner 18, but may be a device that is not indispensable for traveling the vehicle 12 directly, such as audio. Good.

  In the embodiment described above, the negative pressure ΔP in the brake booster 30 is the absolute value of the differential pressure between the absolute pressure P1 at atmospheric pressure and the absolute pressure P2 in the negative pressure chamber 52 (ΔP = | P1−P2 |). However, the present invention is not limited to this. For example, the negative pressure in the brake booster 30 may be defined as the absolute pressure P2 in the negative pressure chamber 52.

  The brake operation force acquisition means according to the present invention detects a traction control system (TCS) function for controlling idling of a drive wheel using a vehicle brake hydraulic pressure control device or the like, and detects an understeer state or an oversteer state when turning. Vehicle stability assist system including a function to stabilize the vehicle behavior by increasing the braking force of the inner wheel or the outer wheel and applying a yaw moment to correct the understeer state or oversteer state You may make it acquire the hydraulic pressure from the hydraulic pressure sensor which (VSA) has.

DESCRIPTION OF SYMBOLS 10 ... Vehicle control device 12 ... Vehicle 14 ... Internal combustion engine 16 ... Brake device 18 ... Air conditioner (auxiliary machine) 26 ... Throttle valve 28 ... Brake pedal (brake operation part) 30 ... Brake booster 42 ... Housing 46 ... Diaphragm 50 ... Transformer Chamber 52 ... Negative pressure chamber 64 ... Atmospheric pressure sensor 66 ... Negative pressure sensor 68 ... Water temperature sensor 70 ... Flake sensor 72 ... Accelerator sensor 74 ... Shift position sensor 76 ... Vehicle speed sensor 78 ... Road surface gradient sensor 80 ... Negative pressure calculation unit 82 ... Negative pressure threshold setting unit 84 ... Negative pressure determination unit 86 ... Air conditioner drive control unit 88 ... Internal combustion engine drive control unit

Claims (8)

An auxiliary machine driven by an internal combustion engine;
In a vehicle control device applied to a vehicle, comprising: a brake booster that increases a braking force of a brake using intake pressure of the internal combustion engine;
Atmospheric pressure acquisition means for acquiring atmospheric pressure;
Negative pressure acquisition means for acquiring negative pressure in the brake booster;
Negative pressure threshold setting means for setting a negative pressure threshold based on the atmospheric pressure acquired by the atmospheric pressure acquisition means;
Auxiliary drive control means for stopping or limiting the drive of the auxiliary machine based on the negative pressure acquired by the negative pressure acquisition means and the negative pressure threshold set by the negative pressure threshold setting means;
A vehicle control device comprising: The vehicle control device according to claim 1,
The negative pressure acquisition means acquires the absolute value of the differential pressure between the absolute pressure of the atmospheric pressure and the absolute pressure of the intake air introduced into the brake booster as a negative pressure,
The negative pressure threshold setting means sets the negative pressure threshold smaller as the atmospheric pressure acquired by the atmospheric pressure acquisition means is lower,
The accessory drive control means stops or restricts the driving of the accessory when the negative pressure acquired by the negative pressure acquisition means is smaller than the negative pressure threshold set by the negative pressure threshold setting means. A control apparatus for a vehicle. The vehicle control device according to claim 2,
The negative pressure threshold setting means sets the negative pressure threshold when the vehicle is in a creep running state to be larger than the negative pressure threshold when the vehicle is in a stopped state. apparatus. The vehicle control device according to claim 2 or 3,
Road surface gradient acquisition means for acquiring the gradient of the road surface on which the vehicle is running or stopped,
The vehicle control apparatus, wherein the negative pressure threshold value setting means sets the negative pressure threshold value larger as the road surface gradient acquired by the road surface gradient acquisition device is larger. In the vehicle control device according to any one of claims 2 to 4,
Brake operation force acquisition means for acquiring the operation force input to the brake operation unit,
The vehicle control apparatus, wherein the negative pressure threshold setting means sets the negative pressure threshold larger as the brake operating force acquired by the brake operating force acquisition means is larger. In the vehicle control device according to any one of claims 2 to 5,
A cooling water temperature acquisition means for acquiring a temperature of cooling water for cooling the internal combustion engine;
The negative pressure threshold setting means sets the negative pressure threshold when the temperature acquired by the cooling water temperature acquisition means is equal to or lower than a predetermined temperature, and the temperature acquired by the cooling water temperature acquisition means is the predetermined temperature. The vehicle control device is set to be larger than the negative pressure threshold when the pressure is higher. In the vehicle control device according to any one of claims 1 to 6,
An accelerator pedal operation detecting means for detecting whether or not the accelerator pedal is operated;
Shift position detecting means for detecting the shift position of the transmission;
Vehicle speed detecting means for detecting the vehicle speed,
The auxiliary machine drive control means drives the auxiliary machine when the shift position of the transmission is at a forward drive position or a reverse drive position and the vehicle speed is equal to or lower than a predetermined value when the accelerator pedal is not operated. A vehicle control device characterized by stopping or restricting. The vehicle control device according to any one of claims 1 to 7,
Restart that automatically restarts the internal combustion engine based on the negative pressure acquired by the negative pressure acquisition means and the negative pressure threshold when the internal combustion engine is stopped while the vehicle is stopped Means for providing a vehicle control device.

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