JP2009161121A - Vehicular brake control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure braking force and improve braking operation feeling by securing sufficient negative pressure and properly increasing operating physical force even at the time of vehicular constant speed travel control in a vehicular brake control device. <P>SOLUTION: A throttle valve 229 provided in an induction pipe 227 of an engine 12 is closed if a rotation speed of the engine 12 exceeds a predetermined value, and execution of a fuel cut is detected when constant speed travel control is in execution, wherein output power of the engine 12 and motors 16, 19 are adjusted so as to obtain a predetermined target vehicle speed in a hybrid vehicle 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicular braking control device capable of increasing an operating force generated by operating a brake pedal by an intake negative pressure of an engine and outputting a master cylinder pressure as a braking force, and in particular, traveling using an engine and an electric motor as a power source. The present invention relates to a vehicular braking control apparatus for a hybrid vehicle.

  In recent years, a hybrid vehicle has been proposed that is equipped with an engine that outputs torque by the combustion of fuel and an electric motor that outputs torque by supplying electric power, and can travel by transmitting the torque of the engine and the electric motor to wheels. Has been. In such a hybrid vehicle, driving and stopping of the engine and the electric motor are controlled according to the driving state, so that the wheel is driven only by the torque of the electric motor, or the wheel is driven by the torque of both the engine and the electric motor. The electric motor can be driven by the electric power stored in the battery. When the energy of the battery decreases, the engine is driven to charge the battery.

  That is, in the hybrid vehicle, an engine and an electric motor are provided as a driving force source, and a planetary gear that combines the power of the engine and the electric motor and transmits it to the wheels is provided. Specifically, the output shaft of the engine is connected to the planetary gear carrier, the output shaft of the electric motor is connected to the ring gear of the planetary gear, and power is transmitted from the sprocket connected to the ring gear to the wheels. It is configured. A generator is provided between the planetary gear and the engine, and the rotating shaft of the generator is connected to the sun gear of the planetary gear. Therefore, the engine power is divided into wheels and a generator by the planetary gear, and the engine rotation speed can be controlled by controlling the rotation speed of the generator. That is, the power split mechanism constituted by the planetary gears has a function of converting the rotational speed of the engine and a function of splitting the engine power into wheels and a generator.

  In this hybrid vehicle braking control device, the brake pedal is connected to a brake booster, and the master cylinder is connected to the brake booster. This brake booster generates an assist force having a predetermined boost ratio with respect to a depression operation of a brake pedal by a driver, and a negative pressure chamber partitioned by a diaphragm is connected to an intake manifold of the engine. Therefore, when the driver steps on the brake pedal, the communication hole of the positive pressure chamber opens and the diaphragm moves to the negative pressure chamber side, and the operating force is boosted. The oil can be pressurized to ensure a predetermined braking oil pressure.

  In such a braking control device for a hybrid vehicle, a brake negative pressure device that is connected to an intake system of an engine and obtains a negative pressure by intake air is connected to the brake booster. However, since this brake negative pressure device obtains a negative pressure by intake air, it is difficult to generate a negative pressure depending on the operating state of the engine, and there is a possibility that an appropriate braking force cannot be ensured due to a lack of the negative pressure.

  Therefore, for example, in the control device for an internal combustion engine described in Patent Document 1 below, the brake booster is connected to the branch pipe connected to one cylinder among the four cylinders by a negative pressure pipe, and the negative pressure in the branch pipe is reduced. Introduces driving pressure to assist the brake pedal force, connects the negative pressure pipe to the branch pipe downstream of the valve member, and if the negative pressure in the brake booster is higher than the required negative pressure, the throttle opening in all cylinders If the negative pressure in the brake booster is smaller than the required negative pressure, the throttle opening of the throttle device installed in the branch pipe to which the negative pressure pipe is connected is I try to narrow down according to.

JP 2003-227357 A

  By the way, there is one that performs constant speed running control (cruise control) that performs constant vehicle speed control so that the vehicle speed of the vehicle becomes a target vehicle speed as a means for reducing the driving operation of the vehicle by the driver. In this constant speed traveling control, it is difficult to generate a negative pressure during execution. That is, an engine applied to a hybrid vehicle is usually an Atkinson cycle or a Miller cycle, and is based on a positive displacement internal combustion engine and has an expansion ratio larger than a compression ratio to improve thermal efficiency. Compared to the Otto cycle, which is a constant volume cycle, it is difficult to generate negative pressure during normal driving of the vehicle.

  When the driver depresses the brake pedal and secures braking force during constant speed traveling control of the vehicle, there is often an urgency. In this case, if the negative pressure in the brake booster cannot be ensured to a predetermined amount, sufficient brake pedaling force cannot be exhibited, and there is a possibility that sufficient braking force required by the driver cannot be obtained.

  The present invention is for solving such a problem, and even at the time of constant speed traveling control of the vehicle, by securing a sufficient negative pressure and appropriately increasing the operating force of the operating member, It is an object of the present invention to provide a vehicle brake control device that secures a sufficient braking force to improve a braking operation feeling and improve reliability and safety.

  In order to solve the above-described problems and achieve the object, a vehicle braking control device according to the present invention is a hybrid vehicle that can run using an engine and an electric motor as a power source, and an operation member that is operated by a driver for braking. , A brake boosting means for increasing and transmitting an operating force generated by operating the operating member using intake negative pressure of the engine, and a pressure of the working fluid generated by the operating force increased by the brake boosting means And a master cylinder that applies a master cylinder pressure as a braking force to a wheel. An engine speed detecting means for detecting the engine speed and a fuel supply to a combustion chamber of the engine. A fuel cut detecting means for detecting execution of the fuel cut to be stopped; and the output of the engine and the electric power so that the vehicle speed becomes a preset target vehicle speed If the engine speed exceeds a predetermined value and the execution of fuel cut is detected when the constant speed running control in which the output of the engine is adjusted is being executed, the intake system of the engine is detected. And a negative pressure control means for closing a throttle valve provided in the engine.

  In the vehicle brake control device of the present invention, a negative pressure detecting means for detecting a negative pressure supplied to the brake boosting means is provided, and the negative pressure control means is configured so that the negative pressure detected by the negative pressure detecting means is in advance. The throttle valve is closed when it is lower than a set judgment value.

  In the vehicle braking control apparatus of the present invention, the negative pressure control means opens the throttle valve after the throttle valve is closed and the negative pressure detected by the negative pressure detection means becomes higher than a determination value. It is a feature.

  In the vehicle brake control device of the present invention, the negative pressure control means closes the throttle valve for a predetermined period when the negative pressure detected by the negative pressure detection means is lower than a determination value. Yes.

  According to the vehicle brake control device of the present invention, constant speed running control is being executed in a hybrid vehicle in which the engine output and the electric motor output are adjusted so that the vehicle speed becomes a preset target vehicle speed. When the engine speed exceeds a predetermined value set in advance and the execution of fuel cut is detected, the throttle valve provided in the intake system of the engine is closed, so constant speed running control is being executed. Even so, by closing the throttle valve, a sufficient negative pressure can be secured, the operation force of the operation member is appropriately increased, a sufficient braking force is secured, and the braking operation feeling is improved. Reliability and safety can be improved.

  Embodiments of a vehicle brake control device according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this Example.

  FIG. 1 is a schematic configuration diagram illustrating a vehicle braking control device according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram illustrating a hybrid vehicle to which the vehicle braking control device of the present embodiment is applied, and FIG. These are the schematic block diagrams showing the engine applied to the hybrid vehicle of a present Example, FIG. 4 is a flowchart showing the booster negative pressure process control in the vehicle brake control apparatus of a present Example.

  The vehicle to which the vehicle brake control device of the present embodiment is applied is a hybrid vehicle, and an engine, an electric motor, and a generator are mounted as a power source. Connected by the distribution integration mechanism, the engine output is distributed to the generator and drive wheels, and the output from the electric motor is transmitted to the drive wheels, or the drive force transmitted from the drive shaft to the drive wheels via the reducer Functions as a transmission.

  That is, as shown in FIG. 2, the hybrid vehicle 11 of this embodiment includes a three-shaft power distribution and integration mechanism 15 connected to the engine 12 and a crankshaft 13 as an output shaft of the engine 12 via a damper 14. A motor (MG1) 16 connected to the power distribution and integration mechanism 15; a reduction gear 18 attached to a ring gear shaft 17 as a drive shaft connected to the power distribution and integration mechanism 15; and the reduction gear 18 And a hybrid electronic control unit (hereinafter referred to as a hybrid ECU) 20 for controlling the entire power output apparatus.

  The engine 12 is an internal combustion engine that outputs power using a hydrocarbon-based fuel such as gasoline or light oil, and an engine electronic control unit (hereinafter referred to as an engine ECU) that receives signals from various sensors that detect the operating state of the engine 12. 21) receives operation control commands such as fuel injection control, ignition control, and intake air amount adjustment control. The engine ECU 21 can communicate with the hybrid ECU 20, controls the operation of the engine 12 by a control signal from the hybrid ECU 20, and outputs data related to the operating state of the engine 12 to the hybrid ECU 20 as necessary.

  The power distribution and integration mechanism 15 includes an external gear sun gear 22, an internal gear ring gear 23 disposed concentrically with the sun gear 22, a plurality of pinion gears 24 that mesh with the sun gear 22 and mesh with the ring gear 23, It has a carrier 25 that holds a plurality of pinion gears 24 so as to rotate and revolve, and is configured as a planetary gear mechanism that performs differential action using the sun gear 22, the ring gear 23, and the carrier 25 as rotating elements. In the power distribution and integration mechanism 15, the crankshaft 13 of the engine 12 is connected to the carrier 25, the motor 19 is connected to the sun gear 22, and the reduction gear 18 is connected to the ring gear 23 via the ring gear shaft 17. When the motor 16 functions as a generator, the power from the engine 12 input from the carrier 25 is distributed to the sun gear 22 side and the ring gear 23 side according to the gear ratio. When the motor 16 functions as an electric motor, the carrier 25 The power from the engine 12 input from the power and the power from the motor 16 input from the sun gear 22 are integrated and output to the ring gear 23 side. The power output to the ring gear 23 is finally output from the ring gear shaft 17 through the gear mechanism 26 and the differential gear 27 to the drive wheels 28 of the vehicle.

  Each of the motor 16 and the motor 19 can be driven as a generator and is configured as a well-known synchronous generator motor that can be driven as an electric motor, and exchanges electric power with the battery 31 via inverters 29 and 30. The power line 32 connecting the inverters 29 and 30 and the battery 31 is configured as a positive bus and a negative bus shared by the inverters 29 and 30, and the electric power generated by either the motor 16 or 19 is transmitted to another motor. It can be consumed at. Therefore, the battery 31 is charged / discharged by electric power generated from one of the motors 16 and 19 or insufficient electric power. In addition, if the balance of electric power is taken by the motors 16 and 19, the battery 31 is not charged / discharged.

  The motors 16 and 19 are both driven and controlled by a motor electronic control unit (hereinafter referred to as a motor ECU) 33. The motor ECU 33 receives signals necessary for driving and controlling the motors 16 and 19, for example, signals from rotational position detection sensors 34 and 35 for detecting the rotational positions of the rotors of the motors 16 and 19 and current sensors (not shown). The detected phase current applied to the motors 16 and 19 is input, and the motor ECU 33 outputs a switching control signal to the inverters 29 and 30. The motor ECU 33 communicates with the hybrid ECU 20, and controls driving of the motors 16, 19 by a control signal from the hybrid ECU 20 and outputs data related to the operating state of the motors 16, 19 to the hybrid ECU 20 as necessary.

  The battery 31 is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 36. The battery ECU 36 receives signals necessary for managing the battery 31, for example, a voltage between terminals from a voltage sensor (not shown) installed between terminals of the battery 31, and a power line 32 connected to the output terminal of the battery 31. A charging / discharging current from an attached current sensor (not shown), a battery temperature from a temperature sensor (not shown) attached to the battery 31, and the like are input, and data on the state of the battery 31 is communicated to the hybrid ECU 20 as necessary. Output. The battery ECU 36 also calculates the remaining capacity (SOC) based on the integrated value of the charge / discharge current detected by the current sensor in order to manage the battery 31.

  The vehicle is provided with a hydraulic brake device 37 corresponding to the drive wheels 28. The hydraulic brake device 37 is supplied with the braking hydraulic pressure adjusted from the hydraulic control device 38. The hydraulic control device 38 is supplied by a brake electronic control unit (hereinafter referred to as a brake ECU) 39. It is managed. The brake ECU 39 receives a signal (described later) necessary for managing the hydraulic control device 38. That is, the brake ECU 39 is in communication with the hybrid ECU 20, controls the hydraulic control device 38 by a control signal from the hybrid ECU 20, and outputs data relating to the operating state of the hydraulic control device 38 to the hybrid ECU 20 as necessary.

  The hybrid ECU 20 is configured as a microprocessor centered on the CPU 41. In addition to the CPU 41, the hybrid ECU 20 includes a ROM 42 for storing a processing program, a RAM 43 for temporarily storing data, an input / output port and a communication port (not shown). is doing. The hybrid ECU 20 includes an ignition signal from an ignition switch 44, a shift position signal Sr from a shift position sensor (shift position detecting means) 46 that detects the operation position of the shift lever 45, and an accelerator pedal that detects the amount of depression of the accelerator pedal 47. The accelerator opening degree Acc from the position sensor 48, the pedal stroke Sp from the brake pedal stroke sensor (operation stroke detecting means) 50 for detecting the depression amount of the brake pedal (operation member) 49, the vehicle speed V from the vehicle speed sensor 51, the steering wheel A set signal, a cancel signal, and the like for constant speed traveling from an auto cruise switch 52 provided in the vicinity are input via a DSS (driver support system) -ECU 53 via an input port.

  In other words, in order to reduce the driving operation of the vehicle by the driver, the vehicle is made to run at a constant speed so that the vehicle speed becomes the target vehicle speed or to make the vehicle follow the preceding vehicle. A vehicle travel control device that performs automatic travel control, such as adaptive cruise control (ACC), that enables travel control to follow the vehicle is mounted, and the auto cruise switch 52 sets and cancels the vehicle travel control device. .

  Accordingly, when the set signal from the auto cruise switch 52 is input via the DSS-ECU 53, the hybrid ECU 20 sets the vehicle speed V at that time to the target vehicle speed Vt to enter the constant speed travel mode (auto cruise mode). When the cancel signal from the auto cruise switch 52 is input via the DSS-ECU 53, the set target vehicle speed Vt is canceled to cancel the constant speed travel mode. Further, when the accelerator opening degree Acc from the accelerator pedal position sensor 48 or the pedal stroke Sp from the brake pedal stroke sensor 50 is input during the constant speed running mode, the set target vehicle speed Vt is changed. Furthermore, when the set signal from the auto cruise switch 52 is input via the DSS-ECU 53, the hybrid ECU 20 sets the target vehicle speed Vt so that the host vehicle follows the preceding vehicle at that time. Set to constant speed running mode (auto cruise mode). Then, the hybrid ECU 20 controls the drive of the engine 12 and the motors 16 and 19 according to the target driving force calculated according to the target vehicle speed Vt.

  Further, as described above, the hybrid ECU 20 is connected to the engine ECU 21, the motor ECU 33, the battery ECU 36, and the brake ECU 39 via a communication port, and the engine ECU 21, the motor ECU 33, the battery ECU 36, and the brake ECU 39 and various control signals and data. We are exchanging.

  The hybrid vehicle 11 of the present embodiment configured as described above is required torque to be output to the ring gear shaft 17 as the drive shaft based on the accelerator opening Acc corresponding to the depression amount of the accelerator pedal 47 by the driver and the vehicle speed V. The engine 12, the motor 16, and the motor 19 are driven and controlled so that the required driving force corresponding to this required torque is output to the ring gear shaft 17.

  As the drive control of the engine 12, the motor 16, and the motor 19, the engine 12 is driven and controlled so that the drive force corresponding to the required drive force is output from the engine 12, and all of the drive force output from the engine 12 is powered. Torque conversion operation mode for driving and controlling the motor 16 and the motor 19 so that torque is converted by the distribution integration mechanism 15, the motor 16, and the motor 19 and output to the ring gear shaft 17. The engine 12 is driven and controlled so that a driving force commensurate with the required electric power is output from the engine 12, and all or a part of the power output from the engine 12 with charging / discharging of the battery 31 is the power. The requested driving force is applied to the ring gear shaft 17 by torque conversion by the distribution integration mechanism 15, the motor 16, and the motor 19. A charge / discharge operation mode in which the motor 16 and the motor 19 are controlled to be driven, and a motor operation in which the driving of the engine 12 is stopped and a driving force corresponding to the required driving force from the motor 19 is output to the ring gear shaft 17. There are modes.

  Further, as the operation control of the hydraulic brake device 37 by the hydraulic control device 38, the hydraulic control device 38 is operated and controlled so that a braking force corresponding to the required braking force is output from the hydraulic brake device 37. That is, the required braking force of the driver is detected according to the pedal stroke of the brake pedal 49, the regenerative braking by the motor 19 is executed for this required braking force, and the required hydraulic braking force obtained by subtracting the regenerative braking force from the required braking force. Based on this, the hydraulic control device 38 is controlled to operate the hydraulic brake device 37.

  As described above, the hybrid vehicle has the engine 12 and the motors 16 and 19 as power sources, and distributes the outputs of the engine 12 and the motors 16 and 19 by the power distribution and integration mechanism 15 according to the running state. Then, it is transmitted to the drive wheel 28. Since this power distribution and integration mechanism 15 is configured as a planetary gear mechanism, it has backlash or other backlash between the gears, and the shock when the engine 12 starts is amplified by the backlash between the gears. End up. Therefore, the hybrid ECU 20 applies a predetermined torque (vehicle forward side) to the power distribution integration mechanism 15 by operating the motor 16 or the engine 12 when the engine 12 is requested to start. A gear train pressing (backlashing) process in the integrated mechanism 15 is executed (pressing control means).

  By the way, in the hybrid vehicle of the present embodiment, an in-line four-cylinder in-cylinder engine is applied. In this in-line four-cylinder engine 12, as shown in FIG. 3, a cylinder head 202 is fastened on a cylinder block 201, and pistons 204 are respectively movable up and down in a plurality of cylinder bores 203 formed in the cylinder block 201. It is mated. A crankcase 205 is fastened to the lower part of the cylinder block 201, and a crankshaft 206 is rotatably supported in the crankcase 205. Each piston 204 is connected to the crankshaft 206 via a connecting rod 207. Has been.

  The combustion chamber 208 is constituted by the wall surface of the cylinder bore 203 in the cylinder block 201, the lower surface of the cylinder head 202, and the top surface of the piston 204. The combustion chamber 208 has a high central portion at the upper portion (the lower surface of the cylinder head 202). It has a pent roof shape that is slanted. An intake port 209 and an exhaust port 210 are formed on the upper portion of the combustion chamber 208, that is, the lower surface of the cylinder head 202, and the intake valve 211 and the exhaust valve are opposed to the intake port 209 and the exhaust port 210. The lower end portions of 212 are respectively positioned. The intake valve 211 and the exhaust valve 212 are supported by the cylinder head 202 so as to be movable in the axial direction, and are urged and supported in a direction in which the intake port 209 and the exhaust port 210 are closed (upward in FIG. 3). ing. An intake camshaft 213 and an exhaust camshaft 214 are rotatably supported by the cylinder head 202, and the intake cam 215 and the exhaust cam 216 are in contact with the upper ends of the intake valve 211 and the exhaust valve 212.

  Although not shown, the crankshaft sprocket fixed to the crankshaft 206 and the camshaft sprockets respectively fixed to the intake camshaft 213 and the exhaust camshaft 214 are wound with endless timing chains. The crankshaft 206, the intake camshaft 213, and the exhaust camshaft 214 can be interlocked.

  Accordingly, when the intake camshaft 213 and the exhaust camshaft 214 rotate in synchronization with the crankshaft 206, the intake cam 215 and the exhaust cam 216 move up and down the intake valve 211 and the exhaust valve 212 at a predetermined timing. 209 and the exhaust port 210 can be opened and closed, and the intake port 209 and the combustion chamber 208 can communicate with the combustion chamber 208 and the exhaust port 210, respectively. In this case, the intake camshaft 213 and the exhaust camshaft 214 are set to rotate once (360 degrees) while the crankshaft 206 rotates twice (720 degrees). Therefore, the engine 12 executes four strokes of the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke while the crankshaft 206 rotates twice. At this time, the intake camshaft 213 and the exhaust camshaft 214 are set to 1 It will rotate.

  Further, the valve mechanism of the engine 12 is a variable valve timing-intelligent (VVT) mechanism 217, 218 that controls the intake valve 211 and the exhaust valve 212 at an optimal opening / closing timing according to the operating state. It has become. The intake / exhaust variable valve operating mechanisms 217, 218 are configured by providing VVT controllers 219, 220 at the shaft end portions of the intake camshaft 213 and the exhaust camshaft 214. The phases of the camshafts 213 and 214 with respect to the cam sprockets are changed by acting on advance and retard chambers (not shown) of the VVT controllers 219 and 220, and the opening and closing timings of the intake valve 211 and the exhaust valve 212 are advanced or retarded. Is something that can be done. In this case, the intake / exhaust variable valve mechanism 217, 218 advances or retards the opening / closing timing while keeping the operating angle (opening period) of the intake valve 211 and the exhaust valve 212 constant. The intake camshaft 213 and the exhaust camshaft 214 are provided with cam position sensors 223 and 224 for detecting the rotational phase.

  A surge tank 226 is connected to the intake port 209 via an intake manifold 225, and an intake pipe 227 is connected to the surge tank 226. An air cleaner 228 is attached to an air intake port of the intake pipe 227. . An electronic throttle device 230 having a throttle valve 229 is provided on the downstream side of the air cleaner 228.

  An exhaust pipe 232 is connected to the exhaust port 210 via an exhaust manifold 231, and the exhaust pipe 232 is a three-way catalyst 233 for purifying harmful substances contained in the exhaust gas and a NOx occlusion reduction type catalyst 234. Is installed. The three-way catalyst 233 simultaneously purifies HC, CO, and NOx contained in the exhaust gas by an oxidation-reduction reaction when the air-fuel ratio (exhaust air-fuel ratio) is stoichiometric. The NOx occlusion reduction type catalyst 234 is in the rich combustion region or the stoichiometric combustion region where the NOx contained in the exhaust gas is temporarily stored when the air-fuel ratio (exhaust air-fuel ratio) is lean, and the oxygen concentration in the exhaust gas is reduced. Sometimes, the stored NOx is released and NOx is reduced by the added fuel as a reducing agent.

  The engine is provided with a turbocharger 235 that rotates the turbine by the energy of the exhaust gas and pushes air into the combustion chamber by a compressor directly connected thereto. The turbocharger 235 is configured such that a compressor 236 provided in an intake pipe 227 and a turbine 237 provided in an exhaust pipe 232 are integrally connected by a connecting shaft 238. The turbocharger 235 is provided with an intercooler 239 that cools intake air that has been compressed by the compressor 236 and has risen in temperature at the intake pipe 227 on the downstream side of the compressor 236.

  The cylinder head 202 is provided with an injector 240 that directly injects fuel into the combustion chamber 208. The injector 240 is located on the intake port 209 side and is inclined at a predetermined angle downward from the horizontal upper end. . An injector 240 attached to each cylinder is connected to a delivery pipe 241. A high pressure fuel pump 243 is connected to the delivery pipe 241 via a high pressure fuel supply pipe 242, so that fuel of a predetermined pressure can be supplied. . The cylinder head 202 is provided with a spark plug 244 that is located above the combustion chamber 208 and ignites the air-fuel mixture.

  The above-described engine ECU 21 is mounted on the vehicle. The engine ECU 21 can control the fuel injection timing of the injector 240, the ignition timing of the spark plug 244, and the like. The detected intake air amount, intake air temperature, The fuel injection amount, injection timing, ignition timing, and the like are determined based on engine operating conditions such as supercharging pressure, throttle opening, accelerator opening, engine speed, and coolant temperature.

  That is, an airflow sensor 245 and an intake air temperature sensor 246 are mounted on the upstream side of the intake pipe 227, and the measured intake air amount and intake air temperature are output to the engine ECU 21. In addition, a supercharging pressure sensor 247 is attached to the surge tank 226, and the measured supercharging pressure is output to the engine ECU 21. The electronic throttle device 230 is provided with a throttle position sensor 248 and outputs the current throttle opening to the engine ECU 21. The crankshaft 206 is provided with a crank angle sensor 249, which outputs the detected crank angle to the engine ECU 21. The engine ECU 21 determines the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke in each cylinder based on the crank angle. At the same time, the engine speed is calculated. The cylinder block 201 is provided with a water temperature sensor 250 and outputs the detected engine cooling water temperature to the engine ECU 21.

  Further, the engine ECU 21 can control the intake and exhaust variable valve mechanisms 217 and 218 based on the engine operating state. That is, when the temperature is low, the engine is started, the engine is idling, or the load is light, the exhaust gas blows back into the intake port 209 or the combustion chamber 208 by eliminating the overlap between the exhaust valve 212 closing timing and the intake valve 211 opening timing. Reduce the amount to enable stable combustion and improved fuel efficiency. Further, at the time of medium load, by increasing the overlap, the internal EGR rate is increased to improve the exhaust gas purification efficiency, and the pumping loss is reduced to improve the fuel consumption. Further, at the time of high-load low-medium rotation, the closing timing of the intake valve 211 is advanced, thereby reducing the amount of intake air blown back to the intake port 209 and improving the volume efficiency. At the time of high load and high rotation, the closing timing of the intake valve 211 is retarded in accordance with the rotational speed, so that the timing is adjusted to the inertial force of the intake air and the volume efficiency is improved.

  In the hybrid vehicle configured as described above, the vehicle brake control device of the present embodiment will be described in detail below.

  In the vehicle brake control apparatus of this embodiment, as shown in FIG. 1, a brake booster (brake booster) 101 is connected to the brake pedal 49, and a master cylinder 102 is fixed to the brake booster 101. ing. The brake pedal 49 is equipped with a brake pedal stroke sensor 50 that detects the amount of depression, that is, a pedal stroke, and outputs the detection result to the brake ECU 39.

  The brake booster 101 can generate an assist force having a predetermined boost ratio with respect to the depression operation of the brake pedal 49 by the driver. In this case, the brake booster 101 is internally partitioned into a positive pressure chamber and a negative pressure chamber by a diaphragm, the positive pressure chamber communicates with the atmosphere via the communication hole, and the negative pressure chamber communicates with the engine via the negative pressure tube 103. Twelve intake manifolds 225 are connected. The negative pressure pipe 103 is provided with a negative pressure sensor (negative pressure detecting means) 104 for detecting a booster negative pressure supplied from the engine 12 to the negative pressure chamber of the brake booster 101. The detection result is sent to the brake ECU 39. Output. Accordingly, when the driver depresses the brake pedal 49, the communication hole of the positive pressure chamber opens and the diaphragm moves to the negative pressure chamber side, so that the operating force is boosted. Since it is connected to the piston, the boosted operating force can be transmitted to the master cylinder 102.

  The master cylinder 102 has two hydraulic chambers (not shown) inside, and in each hydraulic chamber, a master cylinder pressure that combines the brake depression force and the assist force is generated. A reservoir tank 105 is provided above the master cylinder 102, and the master cylinder 102 and the reservoir tank 105 are in communication with each other when the depression of the brake pedal 49 is released.

  The hydraulic pressure supply passages 106 and 107 are connected to the respective hydraulic chambers of the master cylinder 102, and the hydraulic pressure supply passage 106 is connected to a hydraulic pressure control circuit on one drive wheel side in the hydraulic pressure control device 38. Reference numeral 107 denotes a hydraulic control circuit on the other drive wheel side in the hydraulic control device 38. A master cylinder pressure sensor (master cylinder pressure detecting means) 108 that detects the supply hydraulic pressure, that is, the master cylinder pressure, is mounted in one hydraulic pressure supply passage 106, and the detection result is output to the brake ECU 39.

  Master cut valves 109 and 110 are attached to the hydraulic pressure supply passages 106 and 107, and the above-described master cylinder pressure sensor 108 is interposed between the master cylinder 102 and the master cut valve 109 in the hydraulic pressure supply passage 106. Has been placed. The master cut valves 109 and 110 are flow-regulated electromagnetic valves, which are so-called normally open types, and are capable of opening control when energized by the brake ECU 39.

  One hydraulic pressure supply passage 106 is connected to a connecting passage 111 via a master cut valve 109, and the other hydraulic pressure supply passage 107 is connected to a connecting passage 112 via a master cut valve 110. One connection passage 111 is branched into two branch passages 113 and 114, and the other connection passage 112 is branched into two branch passages 115 and 116. The branch passages 113 and 114 are connected to wheel cylinders 117FR and 117RL that drive hydraulic brake devices 37 (37FR and 37RL) disposed in the respective drive wheels 28 (see FIG. 2). The branch passages 115 and 116 are connected to wheel cylinders 117FL and 117RR that drive hydraulic brake devices 37 (37FL and 37RR) disposed on the drive wheels 28 (see FIG. 2), respectively. Although the hydraulic piping system is a cross piping here, it may be a front and rear piping.

  Electromagnetic holding valves 118, 119, 120, and 121 are arranged in the branch passages 113, 114, 115, and 116, respectively. Further, hydraulic discharge passages 122, 123, 124, and 125 branch to the branch passages 113, 114, 115, and 116 from the wheel cylinders 117 FR, 117 RL, 117 FL, and 117 RR from the electromagnetic holding valves 118, 119, 120, and 121. The hydraulic pressure discharge passages 122, 123, 124, 125 are connected to auxiliary reservoirs 126, 127. In addition, electromagnetic pressure reducing valves 128, 129, 130, and 131 are arranged in the hydraulic pressure discharge passages 122, 123, 124, and 125, respectively.

  These electromagnetic holding valves 118, 119, 120, and 121 are flow rate adjustment type electromagnetic valves, which are so-called normally open types, and are capable of opening control when energized by the brake ECU 39. The electromagnetic pressure reducing valves 128, 129, 130, and 131 are flow rate adjustment type electromagnetic valves, which are so-called normally closed types, and are capable of opening control when energized by the brake ECU 39.

  In addition, check valves 132 and 133 are provided in parallel with the master cut valves 109 and 110 between the hydraulic pressure supply passages 106 and 107 and the connection passages 111 and 122, respectively, from the hydraulic pressure supply passages 106 and 107 side. Only the flow of hydraulic oil to the connecting passages 111 and 112 is allowed. The branch passages 113, 114, 115, 116 are provided with check valves 134, 135, 136, 137 in parallel with the electromagnetic holding valves 118, 119, 120, 121, and wheel cylinders 117FR, 117RL. , 117FL, 117RR, only hydraulic fluid flow from the master cut valves 109, 110 side is permitted.

  Pump passages 138 and 139 branched from the connection passages 111 and 112 and connected to the auxiliary reservoirs 126 and 127 are provided, and hydraulic pumps (pressurizing means) driven by the pump motor 140 are provided in the middle of the pump passages 138 and 139. 141 and 142 are disposed, and check valves 143 and 144 are disposed closer to the master cut valves 109 and 110 than the hydraulic pumps 141 and 142. Also, suction passages 145 and 146 branched from the hydraulic pressure supply passages 106 and 107 and connected to the auxiliary reservoirs 126 and 127 are provided, and the reservoir cut check valves 147 and 147 are provided on the auxiliary reservoirs 126 and 127 side of the suction passages 145 and 146. 148 is arranged.

  The brake ECU 39 includes a CPU, a memory, and the like, and executes braking control by executing a stored brake control program. That is, the brake ECU 39 receives the pedal stroke Sp detected by the pedal stroke sensor 50 and the master cylinder pressure Pmc detected by the master cylinder pressure sensor 108. Therefore, the brake ECU 39 controls the master cut valves 109, 110, the electromagnetic holding valves 118, 119, 120, 121, the electromagnetic pressure reducing valves 128, 129, 130, 131, the pump motor based on the pedal stroke Sp and the master cylinder pressure Pmc. 140 is controlled so that the brake hydraulic pressure to the wheel cylinders 117FR, 117RL, 117FL, and 117RR can be adjusted.

  Therefore, normally, the master cut valves 109 and 110 are opened, the electromagnetic holding valves 118, 119, 120, and 121 are opened, and the electromagnetic pressure reducing valves 128, 129, 130, and 131 are closed, and the driver When the brake pedal 49 is depressed, the brake booster 101 generates an assist force having a predetermined boost ratio with respect to the depression operation, and the master cylinder 102 has a master cylinder pressure Pmc that combines the brake depression force and the assist force. Is generated.

  The brake ECU 39 detects the driver's required braking force based on the pedal stroke Sp of the brake pedal 49 and the master cylinder pressure Pmc, and outputs this required braking force to the hybrid ECU 20. The hybrid ECU 20 outputs this required braking force to the motor ECU 33, and the motor ECU 33 controls the regenerative braking and outputs the execution value, that is, the executed regenerative braking force to the hybrid ECU 20. The hybrid ECU 20 sets the required hydraulic braking force by subtracting the regenerative braking force from the required braking force, and the brake ECU 39 controls the hydraulic control device 38 based on the required hydraulic braking force.

  In the brake assist operation mode in the pressure increasing mode of the hydraulic brake device 37, the master ECU 109 and the electromagnetic holding valve 118 are opened, the electromagnetic pressure reducing valve 128 is closed, and the brake ECU 39 is operated as a pump. By driving and controlling the hydraulic pump 141 by the motor 140 and pressurizing the hydraulic oil in the auxiliary reservoir 126, the pressurized pressure by the hydraulic pump 141 in addition to the master cylinder pressure Pmc generated in the master cylinder 102 is connected to the pump passage 138. It circulates through the passage 111, the mast cut valve 109, the hydraulic supply passage 106, and the auxiliary reservoir 126, and acts on the wheel cylinder 117FR via the electromagnetic holding valve 118 and the branch passage 113, and the hydraulic pressure of the wheel cylinder 117FR increases. The braking force is further increased.

  In the vehicular braking control apparatus of this embodiment configured as described above, the brake pedal 49 is connected to the brake booster 101, and the master cylinder 102 is connected to the brake booster 101. As described above, the brake booster 101 generates an assist force having a predetermined boost ratio with respect to the depression operation of the brake pedal 49 by the driver. The negative pressure chamber partitioned by the diaphragm is the negative pressure tube 103. To the intake manifold 225 of the engine. Therefore, when the driver depresses the brake pedal 49, the communication hole of the positive pressure chamber opens and the diaphragm moves to the negative pressure chamber side, so that the operation force is boosted. The predetermined hydraulic pressure (master cylinder pressure) can be secured by pressurizing the hydraulic oil.

  By the way, since the negative pressure supplied to the negative pressure chamber of the brake booster 101 is supplied from the intake manifold 225 of the engine 12, the amount of the negative pressure changes according to the operating state of the engine 12. Further, since the negative pressure in the negative pressure chamber of the brake booster 101 is used when the brake pedal 49 is operated, it changes in accordance with the operating state of the brake. Therefore, in order to properly operate the brake booster 101, it is necessary to maintain the amount of negative pressure in the negative pressure chamber that changes according to the operating state of the engine 12 and the operating state of the brake pedal 49 at a predetermined amount or more.

  In particular, when constant speed traveling control is executed by the vehicle traveling control device and the hybrid vehicle 11 is automatically traveling at a predetermined vehicle speed, it is difficult to maintain the negative pressure amount in the negative pressure chamber at a predetermined amount or more. When the driver depresses the brake pedal 49 to secure the braking force during constant speed traveling control of the vehicle, there is often urgency, and in this case, the negative pressure in the brake booster 102 can be secured to a predetermined amount. If not, sufficient braking force cannot be exerted and sufficient braking force requested by the driver may not be obtained.

  Therefore, in the vehicle braking control device of the present embodiment, a crank angle sensor 249 is provided as an engine speed detecting means for detecting the speed of the engine 12, and a fuel cut for stopping fuel supply to the combustion chamber 208 of the engine 12 is provided. The engine ECU 21 is provided as a fuel cut detection means for detecting the execution of the engine, and the hybrid ECU 20 operates at a constant speed in which the output of the engine 12 and the outputs of the electric motors 16 and 19 are adjusted so that the vehicle speed becomes a preset target vehicle speed. When the control is being executed, when the rotation speed of the engine 12 exceeds a predetermined value set in advance and execution of fuel cut is detected, the throttle valve 229 provided in the intake system of the engine 12 is closed ( Negative pressure control means).

  In this case, the hybrid ECU 20 is configured to close the throttle valve 229 of the engine 12 when the negative pressure detected by the negative pressure sensor 104 is lower than a predetermined determination value.

  Further, in the vehicle brake control device of the present embodiment, the hybrid ECU 20 opens the throttle valve 229 when the negative pressure detected by the negative pressure sensor 104 becomes higher than the determination value after closing the throttle valve 229. Yes. In this case, the hybrid ECU 20 may close the throttle valve 229 of the engine 12 only for a predetermined period when the negative pressure detected by the negative pressure sensor 104 is lower than a predetermined determination value. Good.

  Hereinafter, the negative pressure processing control of the brake booster 101 in the vehicle brake control device of the present embodiment will be described based on the flowchart of FIG.

In the negative pressure processing control of the brake booster 101 in the vehicle brake control device of the present embodiment, as shown in FIG. 4, in step S11, the hybrid ECU 20 causes the engine 12 so that the vehicle speed of the hybrid vehicle 11 becomes the target vehicle speed. It is determined whether constant speed running control for adjusting the output of the motor and the outputs of the electric motors 16 and 19 is being executed. In this case, the hybrid ECU 20 determines whether or not the auto-cruise switch 52 is turned on. If it is determined that the auto-cruise switch 52 is turned on, in step S12, the current engine rotation detected by the crank angle sensor 249 is determined. It is determined whether the number Ne is higher than a predetermined engine speed Ne ₁ set in advance. Here, it is determined whether the current engine speed Ne is if it is determined to be higher than the predetermined engine speed Ne _1, at step S13, fuel cut in the engine 12 is running. Here, if it is determined that the fuel cut in the engine 12 is being performed, the process proceeds to step S14.

On the other hand, in step S11, or it is determined that the auto cruise switch 52 is not turned ON, at step S12, or it is determined that the current engine speed Ne is not higher than the predetermined engine speed Ne _1, step S13 When it is determined that the fuel cut in the engine 12 has not been executed, the routine is terminated without doing anything.

In step S14, the hybrid ECU 20 reads the booster negative pressure Pb detected by the negative pressure sensor 104. Then, at step S15, the hybrid ECU20 determines whether a negative pressure sensor 104 detects the current booster negative pressure Pb is lower than the predetermined booster negative pressure PB ₁ which is set in advance. Here, the current booster negative pressure Pb is when it is determined to be lower than the predetermined booster negative pressure PB _1, at step S16, closes the throttle valve 229 by the electronic throttle device 230 disposed in an intake pipe 227 of the engine 12.

Therefore, when the hybrid vehicle 11 is under constant speed traveling control, the current engine speed Ne is higher than the predetermined engine speed Ne _{1 and} the fuel cut in the engine 12 is being performed, the throttle valve 229 is closed. Then, intake negative pressure of the engine 12 is generated, and the amount of negative pressure increases. In this case, if the throttle valve 229 is closed when the engine speed Ne is high, a sufficient negative pressure can be secured in the intake pipe 227. During the fuel cut in the engine 12, the throttle valve 229 is opened for the purpose of reducing friction, and the throttle valve 229 needs to be closed in order to ensure a sufficient negative pressure in the intake pipe 227.

On the other hand, in step S15, if it is determined that the current booster negative pressure Pb is not lower than the predetermined booster negative pressure PB _1, since the boosting by the brake booster 101 is sufficiently possible at step S17, the electronic throttle device 230, the throttle valve 229 is opened. In step S16, when the throttle valve 229 is closed by the electronic throttle device 230 provided in the intake pipe 227 of the engine 12, the intake negative pressure of the engine 12 is generated and the amount of negative pressure increases. at step S15 in, if it is determined that the current booster negative pressure Pb is not lower than the predetermined booster negative pressure PB _1, to open the throttle valve 229. In practice, the electronic throttle device 230 is controlled in accordance with the operating state of the hybrid vehicle 11 to adjust the opening of the throttle valve 229.

  As described above, in the vehicle brake control device of the present embodiment, the output of the engine 12 and the outputs of the motors 16 and 19 are adjusted in the hybrid vehicle 11 so that the vehicle speed becomes the preset target vehicle speed. When the constant speed traveling control is being executed, if the engine 12 exceeds the predetermined rotation speed set in advance and the execution of fuel cut is detected, the throttle provided in the intake pipe 227 of the engine 12 The valve 229 is closed.

  Therefore, even when the hybrid vehicle 11 is executing the constant speed running control, by closing the throttle valve 229, a sufficient negative pressure can be secured in the brake booster 101, and the brake pedal force of the brake pedal 49 is set appropriately. In addition to ensuring sufficient braking force, the braking operation feeling can be improved, and the reliability and safety can be improved.

  Further, in the vehicle brake control device of the present embodiment, a negative pressure sensor 104 that detects the negative pressure supplied to the brake booster 101 is provided, and the hybrid ECU 20 is preset with a negative pressure that the negative pressure sensor 104 detects. When the value is lower than the determination value, the throttle valve 229 provided in the intake pipe 227 of the engine 12 is closed. Therefore, when the negative pressure required to operate the brake booster 101 is low, the negative pressure generation delay can be suppressed by closing the throttle valve 229.

Further, in the vehicle brake control device of the present embodiment, the hybrid ECU 20 closes the throttle valve 229 and then the current booster negative pressure Pb detected by the negative pressure sensor 104 becomes higher than the predetermined booster negative pressure PB _1. The throttle valve 229 is opened. Therefore, by ensuring that the brake booster 101 has a negative pressure, the throttle valve 229 is closed for a necessary period, so that the deterioration of friction during the constant speed traveling control can be minimized.

  Further, in the vehicle brake control device of the present embodiment, if the engine 12 exceeds the predetermined speed during execution of the constant speed running control and the execution of fuel cut is detected, the intake air of the engine 12 is detected. A throttle valve 229 provided on the pipe 227 is closed for a predetermined period. Therefore, it is possible to simplify the control.

  In the above-described embodiment, the hybrid ECU 20 and the motor ECU 33 are separated, but the control may be performed using an integrated ECU. In addition, the engine ECU 21, the battery ECU 36, the brake ECU 39, and the like may be an integrated ECU.

  As described above, the vehicle braking control apparatus according to the present invention closes the throttle valve when the hybrid vehicle is executing the constant speed running control, the engine speed is high, and the fuel cut is executed. Thus, a sufficient negative pressure is ensured even during the constant speed running control of the vehicle, which is suitable for use in any type of vehicle braking control device.

1 is a schematic configuration diagram illustrating a vehicle brake control device according to an embodiment of the present invention. 1 is a schematic configuration diagram illustrating a hybrid vehicle to which a vehicle brake control device according to an embodiment is applied. It is a schematic block diagram showing the engine applied to the hybrid vehicle of a present Example. It is a flowchart showing the booster negative pressure process control in the brake control apparatus for vehicles of a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Hybrid vehicle 12 Engine 15 Power distribution integration mechanism 16 Motor, MG1, electric motor (electric motor)
19 Motor, MG2, generator (electric motor)
20 Hybrid electronic control unit, hybrid ECU (fuel cut detection means, negative pressure control means)
21 Electronic control unit for engine, engine ECU
31 battery 33 electronic control unit for motor, motor ECU
36 Electronic control unit for battery, battery ECU
37 Hydraulic brake device 38 Hydraulic control device 39 Electronic control unit for brake, brake ECU
46 Shift position sensor 49 Brake pedal (operating member)
50 Brake pedal stroke sensor 52 Auto cruise switch 101 Brake booster (brake booster)
102 Master cylinder 103 Negative pressure tube 104 Negative pressure sensor (negative pressure detection means)
108 Master cylinder pressure sensor 117FR, 117FL, 117RL, 117RR Wheel cylinder 118, 119, 120, 121 Electromagnetic holding valve 128, 129, 130, 131 Electromagnetic pressure reducing valve 141, 142 Hydraulic pump 249 Crank angle sensor (engine speed detection) means)

Claims (4)

A hybrid vehicle capable of running using an engine and an electric motor as a power source,
An operation member that is braked by the driver;
Brake boosting means for enhancing and transmitting the operating force generated by the operation of the operating member using the intake negative pressure of the engine;
A master cylinder that applies a master cylinder pressure, which is a pressure of a working fluid generated by an operation force increased by the brake booster, to a wheel as a braking force;
In a vehicle braking device comprising:
Engine speed detecting means for detecting the engine speed;
Fuel cut detection means for detecting execution of fuel cut to stop fuel supply to the combustion chamber of the engine;
When constant-speed running control is being performed in which the engine output and the electric motor output are adjusted so that the vehicle speed becomes a preset target vehicle speed, the engine speed exceeds a preset predetermined value. And negative pressure control means for closing a throttle valve provided in an intake system of the engine when execution of fuel cut is detected,
A vehicular braking control apparatus comprising:   Negative pressure detection means for detecting negative pressure supplied to the brake boosting means is provided, and the negative pressure control means is configured to detect the negative pressure detected by the negative pressure detection means when the negative pressure is lower than a preset determination value. The vehicular braking control apparatus according to claim 1, wherein the throttle valve is closed.   The vehicle according to claim 2, wherein the negative pressure control means opens the throttle valve when the negative pressure detected by the negative pressure detection means becomes higher than a determination value after the throttle valve is closed. Braking control device.   The vehicular braking according to claim 2, wherein the negative pressure control means closes the throttle valve for a predetermined period when the negative pressure detected by the negative pressure detection means is lower than a determination value. Control device.

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