Abstract: In a method for joining at least two work pieces by friction stir welding wherein the work pieces are placed placed in overlapping relationship and are at least partially plasticized in the area where they are to be joined by a rotating friction tool provided with a pin-like projection which is moved axially into the area of the joint to be formed, the projection on the rotating tool has a length corresponding about to the thickness of the upper work piece and a shoulder around the pin-like projection so that, upon movement of the tool toward the work pieces, the work piece material is plasticized by the rotating pin-like projection which moves axially into the work piece material until it reaches the surfaces of the lowermost workpiece.

Abstract: A brake-by-wire type vehicle brake system is arranged to return a piston of a master cylinder to a normal position by opening a shutoff valve so as to supply a hydraulic pressure of a pump to the master cylinder when the shutoff valve is closed and a stroke simulator is put in shutoff state and to close the shutoff valve when the stroke simulator is put in communicating state by returning the pistons of the master cylinder to the normal position.

Abstract: A brake device comprises a brake cylinder, a reservoir, a pump, a master cylinder, and a pulsation-reduction device. The reservoir serves to accumulate a working liquid discharged from the brake cylinder. The pump serves to pump the working liquid accumulated within the reservoir. The master cylinder serves to receive the working liquid discharged from the pump. The pulsation-reduction device comprises a valve device disposed in a communication channel connecting the downstream side of the pump and the master cylinder. The valve device comprises a spool disposed within the communication channel. The spool is movable along the communication channel in response to differences in pressure between the pump side of the communication channel and the master cylinder side of the communication channel. The movement of the spool operates to open and close at least a part of the communication channel.

Abstract: In an electronic control brake system capable of controlling the braking force by adjusting the hydraulic pressure applied to each wheel cylinder through the use of a pressurization source and a hydraulic pressure adjusting portion, the hydraulic pressure applied to a wheel cylinder is increased by a pressurization source while the brake is not operated during a stop of the vehicle. After that, a master cutoff valve is opened so as to release the hydraulic pressure to a master cylinder. Changes in the master pressure are investigated via a master pressure sensor so as to determine whether there is an abnormality in a stroke simulator or a simulator cutoff valve.

Abstract: In a hydraulic braking system operated by an external force, for vehicles, in particular motor vehicles, having a primary pressure source which is operated by external energy and provide brake pressure to the wheel brakes during normal operation, and which also has a foot-actuated auxiliary pressure source which supplies the wheel brakes with brake pressure during emergency operation, to increase the degree of safety, a special hydraulic circuit is provided wherein, during emergency operation, only comparatively few valves between the wheel brakes and a hydraulic reservoir have to be closed so as to be free of leakage, while operational safety is increased by the valves being connected in series.

Abstract: A vehicle brake control system includes an electric fluid pump that, upon energization thereof, pumps brake fluid from a reservoir to a brake circuit at a position upstream of a pressure control valve, an inlet circuit connecting the inlet opening of the pump to a master cylinder, an inside gate valve installed in the inlet circuit, and a control unit that controls the pressure control valve, the inlet gate valve and the electric fluid pump and carries out a predetermined brake control to adjust the hydraulic pressure of the wheel cylinder by operating the pressure control valve. The control unit is configured to carry out a flow back control after completion of the predetermined brake control. The flow back control is a control wherein the inside gate valve is kept open having the electric fluid pump kept de-energized.

Abstract: A brake system and a brake device for use with automobiles is provided in which braking energy stored in an auxiliary pressure source can be effectively used for braking, even if an electrical system fails. The vehicle brake system includes a proportional pressure control valve for generating braking liquid pressure by adjusting the braking energy stored in the auxiliary pressure source. A passage transmits the liquid pressure generated by a brake pedal stroke, a switching valve opens the passage in the powered condition and closes the passage in the off-powered condition, and an auxiliary control portion activates the proportional pressure control valve. Even in the off-powered condition, the high pressure accumulated in the auxiliary pressure source can be used to adjust the required braking liquid pressure at the proportional pressure control valve.

Abstract: First and second pumps are integral in that the pumps are driven by a common motor. The first pump is driven in pumping motion by an eccentric disposed on the motor shaft and the second pump is driven in pumping motion by an end of the motor shaft. The first pump can be an ABS pump and the second pump can be a pre-charge pump. The first and second pumps can be disposed in a common block housing and the common block housing can define a fluid path extending from the outlet of the second pump to the inlet of the first pump. A third pump can be susbtantially similar to the first pump and be disposed on an opposite side of the shaft as the first pump. The third pump can be driven in pumping motion by the eccentric. A separate feed line can be directed from the reservoir of the brake system to the second pump to improve performance.

Abstract: A braking system includes an accumulator positioned along the brake line between the wheel brake and a pump. The accumulator includes a cylinder defining a bore and a piston fitted within the bore. The cylinder defines an inlet and an outlet fluidically connecting the bore to the brake line. The outlet is axially spaced from the inlet and is positioned to be sealed closed by the piston when it is proximate to inlet. The accumulator stores a reserved volume of fluid that is not delivered to the pump via the outlet to thereby reduce the volume of fluid delivered to the master cylinder by the pump and prevent damage to the lip seals during ABS control.

Abstract: An anti-lock controller controls an anti-lock brake system so as to realize any of a pressure decreasing mode where a normally-opened electromagnetic valve is closed, while a normally-closed electromagnetic valve is opened, a holding mode where the normally-opened electromagnetic valve is closed and the normally-closed electromagnetic valve is closed, and a pressure increasing mode where the normally-opened electromagnetic valve is opened, while the normally-closed electromagnetic valve is closed. Then, in the holding mode, for example, in the event that a predetermined condition is established where the voltage of a power supply for a vehicle or the terminal voltage of the normally-opened electromagnetic valve is equal to or smaller than a set value which is determined in advance, a current value that is applied to the normally-opened electromagnetic valve is controlled so as to become smaller than a current value that is applied to the normally-opened electromagnetic valve in the pressure decreasing mode.

Abstract: An improved electro-hydraulic brake system having an electrically powered normal source of pressurized hydraulic brake fluid, and a manually powered backup source of pressurized hydraulic brake fluid to all four of the vehicle brakes in the event of failure of the normal source. During normal braking, fluid from the backup source is redirected from the vehicle brakes to a pedal simulator. The brake system of the invention further diverse arrangements for providing braking in the event of a failure of the normal source of pressurized fluid. The brake circuit for the front wheels are provided with relatively low cost fluid separator units, while the rear brake circuit is not.

Abstract: A hydraulic booster is provided between a M/C pressure and a W/C pressure. The hydraulic booster is composed of a pump and an amplifying piston amplifying the brake fluid amount discharged from the pump. The brake fluid discharged from the amplifying piston is supplied to the W/C via a first pipeline. The brake fluid discharged from the pump is supplied directly to the W/C via a second pipeline. First and a second control valves select the first or the second pipeline as a pressurizing path to the wheel cylinder.

Abstract: An electronically controlled brake system for automobiles is disclosed. This brake system has a low/intermediate pressure accumulator, which is connected to both the NC-type solenoid valves and the oil suction line so as to store pressurized oil discharged from the wheel brakes during an ABS pressure reducing mode, and feed the stored pressurized oil to the inlet of an oil pump during an ABS pressure increasing mode. This accumulator also stores pressurized oil outputted from the oil pump to feed the stored pressurized oil to the inlet of the oil pump during an ESP mode. The low/intermediate pressure accumulator of this invention thus acts as a low pressure accumulator during an ABS mode, and acts as an intermediate pressure accumulator during an ESP mode. Due to such a low/intermediate pressure accumulator, it is possible to reduce the number of parts making up the brake system.

Abstract: A brake control device for a vehicle includes a master cylinder, a wheel cylinder, a brake pedal behavior simulator, a normally-open type electromagnetic valve, a normally-closed type electromagnetic valve, and a brake pressure control device. The brake pressure control device includes a pump, a reservoir, and two electromagnetic valves to increase and decrease wheel cylinder hydraulic pressure. When the brake pressure control device is normally operated, a hydraulic pressure in the wheel cylinder is controlled by the brake pressure control device. On the other hand, when the brake pressure control device malfunctions or is abnormally operating, the wheel cylinder hydraulic pressure is controlled by hydraulic pressure generated from the master cylinder. At least the normally-closed type electromagnetic valve is opened when the brake pedal is in the non-operational state.

Abstract: A hydraulic circuit includes an accumulator having an inflow passage which introduces a hydraulic fluid which is discharged from a hydraulic pump into a hydraulic fluid chamber and a discharge passage which discharges the hydraulic fluid from the hydraulic fluid chamber to a hydraulic actuator. The hydraulic circuit includes a valve mechanism which restricts the supply of hydraulic fluid from the hydraulic fluid chamber to the hydraulic actuator when the pressure in the hydraulic fluid chamber is less than a set pressure and which releases the restriction of the supply of hydraulic fluid to the hydraulic actuator when the pressure in the hydraulic fluid chamber is at least the set pressure. The valve mechanism may be installed inside the accumulator.

Abstract: A storage chamber for a hydraulic vehicle brake system is embodied as a gas separator, with two fluid connections disposed at different heights. Wheel brake cylinders of an auxiliary force brake system are connected to the fluid connection located at a low level and can be actuated by muscle force if there is a malfunction of an external-energy service brake system. The gas separator keeps gas bubbles away from the fluid connection located at the low level and thereby prevents gas bubbles from getting into the brake fluid of the muscle force auxiliary brake system, in order to assure the function of that system.

Abstract: An electro-hydraulic control unit for a controlled braking system includes a hydraulic control unit (HCU) having a controlled braking pump and a pre-charge pump driven by a single motor. The HCU also includes one or more hydraulic components for controlling a flow of hydraulic fluid in the braking apparatus.

Abstract: An improved hydraulic brake system for a vehicle is proposed which includes a hydraulic pressure supply unit for supplying hydraulic pressure from a pressure adjusting valve or an hydraulic pressure source to a pressure chamber of a master cylinder. In this type of brake system, when the hydraulic pressure supply unit is activated, the master piston of the master cylinder could retract to its original position, thus bringing the master pressure chamber into communication with the atmospheric reservoir. If this happens, the master cylinder pressure output will be lost completely. An inexpensive solution to this problem is proposed. A piston retraction restricting member is provided in a pressure chamber for applying pressure to the master piston.

Abstract: An anti-locking brake system for a land vehicle, which is set up in particular for traction control and vehicle dynamics control, comprises a pump (42) for actuating a wheel brake (37) which removes brake fluid from a brake pressure generating unit (31) and supplies it to the wheel brake (37), wherein a first valve arrangement (1) blocks in a non-actuated (normal) position (1.1) the connection between the brake pressure generating unit (31) and an input connection (42e) of the pump (42) and in at least one actuated position (1.3) establishes a primary flow connection (A), a first electromagnetic valve (50) establishes in a non-actuated position (50.1) the connection between an output connection (42a) of the pump (42) and the brake pressure generating unit (31), and blocks it in an actuated position (50.

Abstract: A braking system including (a) a hydraulically operated brake cylinder for operating a brake, (b) a master cylinder operable according to an operation of a manually operable brake operating member, to pressurize a working fluid, (c) a master-cylinder cut-off valve connected to the master cylinder, (d) a high-pressure source such as a power-operated pressure-control cylinder disposed between the master-cylinder cut-off valve and the brake cylinder and operable according to the operation of the brake operating member, to pressurize the fluid, the high-pressure source including a power-operated drive device and a pressure-control cylinder having a control piston which is operable by the power-operated drive device and which partially defines on respective front and rear sides thereof a front control-pressure chamber connected to the brake cylinder, and a rear pressure chamber which is held in communication with the master cylinder, and (e) a braking-pressure control device (200) operable to control the power-ope

Abstract: An electronically controlled brake system for automobiles is disclosed. In the brake system, a first check valve is mounted at an upstream position of an oil suction line which guides pressurized oil from the master cylinder to the inlet of the oil pump during a TCS mode, while a second check valve is mounted on an oil feeding line, which guides pressurized oil from the intermediate-pressure accumulator to the inlet of the oil pump through the oil suction line. The valves of both the oil suction line and the oil feeding line in the brake system are mechanically operated check valves. Therefore, the brake system of this invention is easily and simply controlled, and it is possible to accomplish the recent trend of compactness of hydraulic blocks, and reduce the production cost of the brake system.

Abstract: An electronically controlled brake system for automobiles is disclosed. This brake system has a low/intermediate pressure accumulator, which is connected to both the NC-type solenoid valves and the oil suction line so as to store pressurized oil discharged from the wheel brakes during an ABS pressure reducing mode, and feed the stored pressurized oil to the inlet of an oil pump during an ABS pressure increasing mode. This accumulator also stores pressurized oil outputted from the oil pump to feed the stored pressurized oil to the inlet of the oil pump during an ESP mode. The low/intermediate pressure accumulator of this invention thus acts as a low pressure accumulator during an ABS mode, and acts as an intermediate pressure accumulator during an ESP mode.

Abstract: A brake system (10) having a brake booster (12) that is responsive to an operator brake input for providing a first input force to a master cylinder (13) to develop a first brake application and is responsive to a hydraulic input for providing a second input force to a master cylinder (13) to develop a second brake application. An electronic control unit (ECU) (40) receives first input signals from sensors (19) indicative of a speed for each wheel (14,14′,18,18′) in a brake system of the vehicle. The ECU (40) supplies a pump (42) with an operational input signal when a sensed wheel speed indicates a wheel lock may occur between a wheel and a surface during a brake application and simultaneous activates a decay valve (17) to release pressurized fluid from actuation of the wheel brake associated with the wheel.

Abstract: An electric control apparatus of a brake is provided with a second reservoir, in which a brake fluid is stored in advance, separately from a control device of a brake hydraulic pressure. The second reservoir communicates with a pump, which is an original component of the control device, on the side of a suction opening of the pump through a second liquid passage equipped with a first on-off valve. A first liquid passage is equipped with a second on-off valve. The pump is operated with the first on-off valve being opened to supply a brake hydraulic pressure corresponding to the quantity of an operation of a brake pedal in a sate in which the second on-off valve is closed to a wheel cylinder as an electric control mode of a brake hydraulic pressure of an electronic control unit.

Abstract: Automotive hydraulic pressure brake system with a stroke simulator is proposed which while the electric control system is functioning properly, the supply of hydraulic pressure from a master cylinder is cut off and hydraulic pressure is generated by a power pump. This improves response upon rapid pressure increase while minimizing the increase of pedal stroke and the worsening of the pedal feeling. A bypass is provided to communicate the master cylinder to the wheel cylinders while bypassing an on-off valve to be closed during ordinary braking. A shut-off valve is provided in the bypass and a check valve or a relief valve for allowing only a fluid flow from the master cylinder toward the wheel brake cylinders is provided.

Abstract: A brake pressure transducer is to be provided for a hydraulic vehicle brake system that can be actuated by initiating an actuating force (FB) via an actuating element (2) in order to generate a brake pressure for at least one wheel brake (3) by reducing the volume of a hydraulic chamber (4) and that is equipped with a brake force booster (13) in order to superimpose a primary servo force (FS1) on the initiated actuating force (FB). An additional hydraulic chamber (6) is provided whose volume likewise decreases on initiating the actuating force (FB).

Abstract: A vehicular brake control apparatus performs braking force limiting control for limiting, if the vehicle is in a predetermined driving state, braking forces applied to rear wheels of the vehicle in comparison with the braking forces applied to the front wheels. If it is judged during the braking force limiting control that the amount of braking operation by the driver has increased, the apparatus increases the braking forces applied to the rear wheels.

Abstract: To improve the control behavior of an automotive vehicle control system, such as an anti-lock system (ABS), a driving stability control system (ESP, ASMS, DDC), etc., in a brake system which includes a master cylinder, inlet and outlet valves for pressure modulation, a low-pressure accumulator, and a hydraulic pump for returning the pressure fluid discharged, when a wheel becomes unstable and upon commencement of the ABS control, that branch of the control system to which the unstable wheel is connected is temporarily uncoupled from the master cylinder pressure (pHZ) or initial pressure by closing the pressure fluid conduit in the direction from the wheel brakes to-the master cylinder, and a relatively quick rise of the braking pressure and a quick approach of the wheel braking pressure to the master cylinder pressure (pHZ) and, thus, the wheel lock pressure level is caused by returning pressure fluid from the low-pressure accumulator into this branch.

Abstract: A slave operated self-contained hydraulic brake system having an electric motor that is mounted on a gear housing. The electric motor moves a threaded rod in a lateral direction. Movement in a first direction results in contact of the rod with a master cylinder piston assembly within a master cylinder. Movement of the master cylinder piston assembly forces hydraulic fluid out of the master cylinder to actuate brakes of a towed vehicle. A pressure sensor is attached to the master cylinder and measures the hydraulic fluid pressures in master cylinder chamber. Movement of the rod in a second direction is detected by a reverse limit switch. Electrical signals are used to control the slave operated self-contained hydraulic brake system. The brake system communicates electrically with a brake control board. Sensors may be provided to provide information to a microprocessor on the control board to add control features to the brake system.

Abstract: The present invention relates to an automotive vehicle brake system with wheel slip control which is provided with a non-return valve, between a secondary and a primary circuit. Initially, both circuits are evacuated for filling the brake system with pressure fluid, and evacuation of the secondary circuit is effected by way of the valve that opens. The present invention teaches providing this valve with an additional device by way of which the opening pressure of the valve is automatically increased after filling the brake system with brake fluid. The opening pressure shall be increased at least to such an extent that the valve closure member remains in the closing position at least during normal operation of the brake system. It is achieved by this provision that the secondary circuit can be sufficiently evacuated for the purpose of being filled with brake fluid, without a vacuum being generated later in the secondary circuit during a braking operation.

Abstract: A control method of a hydraulic pressure source-driving type vehicle hydraulic brake system is provided in which water hammering or worsening of the brake feeling does not occur when brake liquid is replenished through a replenish passage. A motor for driving a pump is actuated at a full driving force with an on-off valve in the brake liquid replenish passage opened in the stage in which the hydraulic pressure difference between the master cylinder pressure and the brake hydraulic pressure is small. Also, in the stage in which the brake hydraulic pressure is increased, so that the hydraulic pressure difference from the master cylinder hydraulic pressure has entered a predetermined range, a solenoid valve in the replenish passage is closed to return to the normal control in which the driving force of the motor is controlled so as to correspond to the hydraulic pressure difference.

Abstract: A mechanical oil pressure control apparatus for an antilock brake system including a recessed first body having an oil inlet passage communicating with a master cylinder and an oil outlet passage communicating with a wheel cylinder, a hollow second body threadedly coupled to a front end of the first body, a cylinder member sealably inserted into the first body to define an oil chamber communicating with the oil inlet and outlet passages, a piston slidably fitted in the cylinder member while being subjected to an oil pressure supplied from the master cylinder and exerted in the oil chamber in such a fashion that it slides axially in the oil chamber between a front position where the oil chamber is allowed to communicate with both the oil inlet and outlet passages and a rear position where the communication of the oil chamber with the oil outlet passage is cut off, a compression coil spring received in the second body and adapted to always urge the piston toward the front position against the oil pressure exert

Abstract: To provide for non-powered evacuation and filling of an anti-lock brake system with integrated control units, a check valve is placed between the suction side of the ABS pump (16) and the wheel brake (6). The check valve (26) enables evacuation and filling of the brake system without energizing electro-magnetically operated, normally closed valves at the place of vehicle assembly. With the check valve (26) in its suggested position, a release of the brake pedal after a brake operation cannot cause trapping of vacuum as previously observed in the pressure relief line as the pressure on the side of the brake line remains above atmospheric pressure and keeps the check valve closed.

Abstract: The present invention relates to an automotive vehicle brake system with wheel slip control which is provided with a so-called filling valve, i.e., a non-return valve, between a secondary and a primary circuit. Initially, both circuits are evacuated for filling the brake system with pressure fluid, and evacuation of the secondary circuit is effected by way of the non-return valve that opens. The present invention suggests providing this valve with a blocking device which becomes effective when the brake is actuated for the first time, thereby causing pressure build-up in the primary circuit. The blocking device retains the valve closure member on the valve seat member, with the result that the non-return valve remains closed in the normal operation of the brake system. It is prevented by this provision that vacuum develops in the secondary circuit during a braking operation.

Abstract: A multi-way pressure control valve for an electromagnetically actuatable multi-way control valve for slip-controlled hydraulic automotive vehicle brake systems, for providing a flow connection between at least one wheel brake and a high-pressure source or a low-pressure accumulator.

Abstract: In a braking force control apparatus for realizing both of a BA control for generating a great braking force when an emergency braking operation is executed and an ABS control for restricting a slip ratio of a wheel, an interference between the BA control and the ABS control is prevented. It is determined whether or not the ABS control is executed with respect to at least one of front wheels (step 104) when it is determined that the BA control is started. In the case that the ABS control is executed with respect to at least one of the front wheels, it is determined that a large amount of hydraulic pressure is fed to a wheel cylinder of a rear wheel at the same time when the BA control is started, thereby starting a BA slope restricting control for restricting an inlet thereof (step 108). In the case that the ABS control is not executed in the front wheel, a normal BA control is started (step 106).

Abstract: A vehicle capable of performing automatic driving can be braked with a hydraulic braking pressure produced by a master cylinder having a vacuum booster and a hydraulic braking pressure produced by a hydraulic pressure pump provided to an ABS/B-TCS hydraulic pressure control unit. During normal braking, the vehicle performs braking with the hydraulic braking pressure produced by the master cylinder, by controlling a linear solenoid of the vacuum booster in accordance with a command from an automatic driving electronic control unit. If an insufficient braking force is obtained from the hydraulic braking pressure produced by the master cylinder or a failure occurs in the braking system of the master cylinder, the vehicle performs emergency braking with the hydraulic braking pressure produced by the hydraulic pressure pump of the ABS/B-TCS hydraulic pressure control unit HU.

Abstract: The control algorithm for a rear wheel anti-lock brake system includes a subroutine which proportions the applied braking force between front and rear wheel brakes of a vehicle during a braking cycle. The speed of the rear wheels is sensed and used to calculate an estimated vehicle deceleraion. Upon the estimated vehicle deceleration exceeding a deceleration threshold, an isolation valve is closed to hold the brake pressure applied to the vehicle rear brakes constant. Upon further increases of the estimated vehicle deceleration, the isolation valve is selectively opened to increase the rear brake pressure in proportion to the front brake pressure.

Abstract: In a brake by wire system, a linear differential pressure control valve is provided to control accurately wheel cylinder pressure. A brake fluid conduit extending from a reservoir is branched out into two conduits, each of which is transmitted to each of right and left wheel cylinders. A linear differential pressure control valve is disposed in the conduit and an another linear differential pressure control valve in each of the branched out conduits. Brake fluid sucked from the reservoir by a motor pump is discharged to each of the branched out conduits between the valve and the wheel cylinder. The two valves thus connected in series are operative step by step to control the wheel cylinder pressure in accordance with the current commanded in response to brake pedal depression.

Abstract: A brake pressure control device for a vehicle includes a master cylinder, a front wheel brake connected to the master cylinder through a front brake conduit, a rear wheel brake connected to the master cylinder through a rear brake conduit, a front reservoir connected to the front wheel brake and a rear reservoir connected to the rear wheel brake. A front control valve selectively connects the front wheel brake to one of the master cylinder and the front reservoir, and a rear control valve selectively connects the rear wheel brake to one of the master cylinder and the rear reservoir. A front fluid pump discharges brake fluid to the master cylinder from the front reservoir, while a rear fluid pump discharges brake fluid to the master cylinder from the rear reservoir.

Abstract: A hydraulic automotive brake system with wheel slip control, includes a pressure medium source, to which a main pressure line is connected, which leads to a wheel brake, first and second pressure relief line segments connected to the wheel brake and leading to a supply reservoir, and having a pressure modulation valve arranged in it that either separates the supply reservoir from the wheel brake or connects it to the wheel brake, as well as a control orifice valve that is arranged in the main pressure line upstream of the first pressure relief line segment, actuated by changes in the hydraulic pressure.

Abstract: A hydraulic brake system which incorporates several mutually independent brake circuits and does not require additional energy for conducting brake-slip control actions or stability control actions.

Abstract: A vehicular brake system having vehicle stability management includes a hydraulic master cylinder connected to wheel brakes via brake conduits. A pump generates fluid pressures and pressure control valves located between the master cylinder and the wheel brakes regulate the fluid pressures at the wheel brakes to achieve ABS and traction control. A medium pressure accumulator stores fluid pressurized by the pump which is supplied to the wheel brakes via associated control valves to achieve VSM braking control. The brake system has low power requirements because the medium pressure accumulator does not have to be filled quickly, yet the stored pressurized fluid can be released to the wheel brakes to quickly produce the braking pressures necessary for initiating most VSM applications. The pump is used to supplement the accumulator pressures to achieve full VSM control.

Abstract: A vehicle brake system having a wheel brake and first and second conduits in fluid communication with the wheel brake. A master cylinder having an outlet is in fluid communication with the first conduit for supplying pressurized fluid to the first conduit. The brake system further includes an isolation valve movable between a first position, wherein fluid is permitted to flow from the master cylinder to the wheel brake via the first conduit, and a second position, wherein fluid is prevented from flowing from the master cylinder to the wheel brake via the first conduit. The isolation valve is preferably a pilot-operated valve movable between the first and second positions by a pressure differential between the outlet of the master cylinder and the pressure in the second conduit between the boost valve and the wheel brake. A source of pressurized fluid is in fluid communication with the wheel brake via the second conduit.

Abstract: A normal control in which a master cylinder 32 is used as a hydraulic source to increase a wheel cylinder pressure and a brake assist control in which a pump 12 and an accumulator 20 are used as the hydraulic source the wheel cylinder pressure is increased in a state where communication between the master cylinder 32 and the wheel cylinder 44** is intercepted are executed. When a termination request for the brake assist control occurs, first, the wheel cylinder pressure decreased. After the wheel cylinder pressure is decreased enough, communication between the wheel cylinder 44** and the master cylinder 32 is restored.

Abstract: A brake control apparatus includes a first valve to open and close a main line between a master cylinder and a wheel cylinder, a pump connected between a first valve and the wheel cylinder to supply pressurized brake fluid to the wheel cylinder, an auxiliary line connecting the inlet side of the pump to a master cylinder, a second valve to open and close the auxiliary line, a pressure sensor to detect the output pressure of the master cylinder and an electronic control unit which controls the first valve, the second valve, and the pump based upon the pressure detected by the pressure sensor so that the wheel cylinder receives a higher pressure than that of the master cylinder. The electronic control unit also closes the second valve while the pressure sensor detects the pressure over a certain pressure determined by the road surface condition.