Abstract: A vacuum pump for supplying a machine assembly with negative pressure, the vacuum pump including a housing featuring a delivery chamber which includes a chamber inlet opening and a chamber outlet opening for a gaseous fluid; a suction port for establishing a fluid connection to the machine assembly; a suction channel which connects the delivery chamber to the suction port; and a relief channel which connects the delivery chamber to a relief opening of the housing; a delivery member which can rotate in the delivery chamber in a forward rotational direction and a reverse rotational direction. The fluid is suctioned into the delivery chamber through the chamber inlet opening and discharged through the chamber outlet opening by rotating the delivery member in the forward rotational direction.

Abstract: An internal combustion engine includes a block containing a crankshaft and a crankcase surrounding the crankshaft, a plurality of combustion chambers configured to receive an intake fluid and generate exhaust fluid, an exhaust circuit configured to direct the exhaust fluid away from the plurality of combustion chambers, an intake circuit configured to supply the intake fluid to the plurality of combustion chambers, a turbine disposed in the exhaust circuit and having a turbine shaft configured to be driven by the exhaust fluid, a crankcase ventilation circuit configured to direct crankcase fluid away from the crankcase, and a pump disposed in the crankcase ventilation circuit and having a rotor configured to be driven by the turbine shaft to propel the crankcase fluid through the crankcase ventilation circuit.

Abstract: When the automatic analyzer is installed in an environment with a high altitude and different external atmospheric pressures, there is a problem that an amount of vacuum suction decreases due to a decrease in suction performance of a vacuum pump and it is difficult to perform vacuum suction of an analyzed reaction liquid. In view of the above, by newly providing a pressure adjustment mechanism within a flow path connecting a vacuum tank to vacuum pump, it possible to control the pressure difference between a pressure in the vacuum tank and an external atmospheric pressure where the analyzer is installed to be constant regardless of the installation environment. Additionally, by providing a hole in communication with the outside in the vacuum tank or a vacuum bin, it possible to control the pressure difference between the pressure in the vacuum tank and the external atmospheric pressure where the analyzer is installed to be constant regardless of the installation environment.

Abstract: A starting assistance method and device for an internal combustion engine supplied with a fuel that may contain ethanol, and including a fluid connection pipe between an intake manifold and a braking assistance device. The method including determining the engine temperature, determining the outdoor air temperature, blocking the pipe between the intake manifold and the braking assistance device for a given duration during a phase of starting the engine when the temperature of the engine is lower than a first threshold value and the outdoor air temperature is lower than a second threshold value, and freeing the pipe between the intake manifold and the braking assistance device when the engine is rotating autonomously.

Abstract: Turbine assemblies, loss recovery systems, and related fabrication methods are provided for managing temperatures associated with an electrical generator. One exemplary turbine assembly suitable for use in a loss recovery system includes a wheel configured to rotate in response to a portion of a fluid flow bypassing a flow control valve, a generator including a stator assembly disposed about a rotor coupled to the wheel to rotate in response to rotation of the wheel, a conductive structure in contact with the stator assembly, and an insulating structure radially encompassing the conductive structure and the generator. The conductive structure accesses at least a portion of the fluid flow bypassing the flow control valve and impacting the wheel, thereby providing thermal coupling between the stator assembly and the bypass fluid flow to transfer heat from the stator assembly to the bypass fluid flow via the conductive structure.

Abstract: An electric brake booster vacuum pump of a vehicle has a deactivation level determined according to a percentage of maximum available vacuum at the instant altitude of the vehicle. The activation level may be determined in the same way. The invention provides for earlier on-switching of a vacuum pump at altitude, while ensuring that the off-switching value is achievable at low atmospheric pressure.

Abstract: A rotary-vane vacuum pump comprises a stator and a vaned rotor, the stator partly defining an outlet chamber and including an outlet passage opening to the outlet chamber. The rotor is rotatably sealed to the stator; it has a sealing area to block the outlet passage, and, an unsealing area alignable with the outlet passage by rotation of the rotor to periodically unblock the outlet passage. The disclosed pump offers reduced resistance to lubricant oil discharge from the outlet passage, which results in lower differential pressure between inlet and outlet chambers at the end of the pumping cycle.

Abstract: A control system for evaluating a brake booster system includes an engine evaluation module that detects an engine off condition. A pressure evaluation module, during the engine off condition, monitors hydraulic brake line pressure, detects a change in brake booster pressure, and determines a brake booster vacuum decay rate based on the change in brake booster pressure. A fault reporting module detects a brake booster system fault based on the brake line pressure and the brake booster vacuum decay rate.

Abstract: A vacuum assist pump system includes a vacuum assist pump for assisting to a brake system by vacuum, wherein it includes a suction compensation pump connected with the vacuum assist pump. Advantageously, a vacuum compensation reservoir is arranged between the vacuum assist pump and the suction compensation pump. The vacuum compensation reservoir comprises a vacuity sensor for its internal vacuity and two interfaces. One of the two interfaces communicates to the suction compensation pump, the other communicates to the vacuum assist pump.

Abstract: Various systems and methods for an engine system which includes a throttle turbine generator having a turbine which drives an auxiliary generator and disposed in a throttle bypass are described. In some examples, a throttle bypass valve is controlled to adjust airflow through the throttle bypass responsive to airflow to cylinders of the engine. In other examples, an operating parameter such as throttle position is controlled based on transient operating conditions of the engine. In still other examples, charging of a battery is coordinated between the auxiliary generator and a primary generator.

Abstract: A vehicle control device, that controls to suppress a driving force of a vehicle based on an operation of a brake pedal operated when a braking force is generated by a braking device, wherein the brake pedal is connected to a brake booster, that increases an operating force input to the brake pedal by using a brake negative pressure to transmit to brake fluid of the braking device in order to appropriately control by appropriately detecting the operation of the brake pedal; and the driving force is suppressed according to an M/C pressure when the brake negative pressure is higher than a brake negative pressure threshold value, and the driving force is suppressed according to an operation state of the brake pedal when the brake negative pressure is equal to or lower than the brake negative pressure threshold value.

Abstract: Systems and methods for a vehicle brake booster having first and second chambers separated by a diaphragm coupled to a brake pedal are provided. In one example approach, a method comprises applying an exhaust pressure from a vacuum pump to a first chamber of the brake booster, and applying a vacuum pressure from the vacuum pump to a second chamber of the brake booster.

Abstract: A flow-control assembly may include a fluid conduit and a flow-control valve in the fluid conduit. The flow-control assembly may further include a fluid expansion conduit with an inlet defined at least in part by the fluid conduit and configured to selectively receive flow of a fluid from the fluid conduit. The fluid expansion conduit may further include an outlet in fluid communication with the fluid conduit downstream of the flow-control valve. A rotating fluid expander in the fluid expansion conduit may be configured to expand the fluid and thereby rotate and in some embodiments generate electricity. In a first position flow is substantially blocked. In a second position flow is allowed through the fluid expansion conduit. In a third position flow through the fluid conduit is allowed without necessarily passing through the fluid expansion conduit. Related systems and methods are also provided.

Abstract: A vacuum accumulator system includes a booster, a vacuum accumulator disposed in fluid communication with the booster and an engine disposed in fluid communication with the vacuum accumulator.

Abstract: A method for regenerating a particulate filter is disclosed. In one example, oxygen is pumped from the intake system of a direct injection turobocharged gasoline engine through a cylinder and into the exhaust system by a compressor. In this way, regeneration of a particulate filter may be accomplished without an auxiliary air supply.

Abstract: A method of operating a boosted engine system is described in which an ejector coupled with a fuel vapor purging system can generate vacuum during both purging and non-purging conditions, and during both boosted and non-boosted conditions. The vacuum can therefore be used to power vacuum actuated brakes, and/or other vacuum actuators, irrespective of the purging conditions, and irrespective of boost levels.

Abstract: An engine with an efficient selectively operable vacuum source is disclosed. In one example, an electric vacuum pump with oil wetted seals provides vacuum to a vehicle. The approach may provide for improved efficiency when generating vacuum.

Abstract: A method of operating a boosted engine system is described in which an ejector coupled with a fuel vapor purging system can generate vacuum during both purging and non-purging conditions, and during both boosted and non-boosted conditions. The vacuum can therefore be used to power vacuum actuated brakes, and/or other vacuum actuators, irrespective of the purging conditions, and irrespective of boost levels.

Abstract: A vacuum accumulator system includes a booster, a vacuum accumulator disposed in fluid communication with the booster and an engine disposed in fluid communication with the vacuum accumulator.

Abstract: An apparatus and method for providing enhanced vacuum to a brake booster of a braking system under certain operational conditions. Vacuum is stored in a reservoir and is controllably released to the brake booster to provide a brake booster vacuum level of at least a predetermined vacuum level threshold in order to avoid brake pedal performance issues being perceived by the driver of motor vehicles utilizing engines utilizing a supplemental brake assist system under conditions where the brake booster vacuum level is less than the predetermined vacuum level threshold.

Abstract: The present invention provides a vacuum intensifier for vehicle brake that stably provides enough negative pressure at a predetermined level or more to a brake booster even though the operational condition of engine and the surroundings change, with simple structure and good assemblage.

Abstract: The present invention relates to an internal combustion engine (1) of the Otto type, comprising an induction pipe (3) in conjunction with the engine's (1) cylinders, a brake servo unit (15), a flow connection (29) for evacuating air from the brake servo unit (15) to the induction pipe (3) for the purpose of building up a vacuum inside the brake servo unit (15), in conjunction with which a Venturi unit (25) is arranged in the flow connection (17, 19) to assist with the building up of the aforementioned vacuum. The internal combustion engine is characterized in that the flow connection (17, 19) comprises a bypass line (29) having a lower flow resistance than the Venturi unit (25), the bypass line (29) being intended to connect the evacuated air past the Venturi unit (25) in the event of a transient vacuum in the induction pipe (3).

Abstract: An arm structure intended for controlling the impulse valve (5) of the oscillating cylinder which performs a back and forth movement whereupon the oscillating cylinder comprises a cylinder body (14), a cylinder chamber (1) formed into the mentioned body, a piston (2) which can be moved in the cylinder chamber with the help of a pressure media, feeding channels (15, 16, 17) of the pressure media to the cylinder chamber (1) and control devices in order to direct the pressure media to the cylinder chamber to various sides of the piston and away from the cylinder chamber in order to achieve a back and forth movement for the piston and whereupon the impulse valves (5) belong to the control devices the operation of which at least one arm (10); (12), which explores mechanically the position of the piston arm (7) the movement of which arm is adjusted to open the pressure relieving channel of the impulse valve (5).

Abstract: The present invention provides a combined gas and liquid pump (46) for an internal combustion engine (10). The pump (46) includes a casing (58) having a cavity (60) containing a rotor (62) and a vane (64) slidably mounted to the rotor (62), wherein the cavity (60) is provided with an inlet (50) connectable to a gas source, a further inlet (48) connectable to a liquid source which is separate to the gas source, and an outlet (56). The rotor (62) and vane (64) are movable to draw liquid and gas into the cavity (60) through the respective inlets (50,48) and to move said liquid and gas out of the cavity (60) through the outlet (56). The inlets (50,48) are arranged through the casing (58) such that fluid is drawn first through one of the inlets and then through the other of the inlets before being discharged through the outlet (56).

Abstract: A circuit inhibits power to a motor driving a pump when a vacuum condition is detected by a vacuum switch associated with the pump. The circuit is only responsive to an actuator for selectively supplying power to the motor after inhibiting power to the motor.

Abstract: An ejector system for a vehicle includes an ejector which generates negative pressure that is greater than negative pressure provided from an intake passage of an intake system of an internal combustion engine, and supplies the generated negative pressure to a negative pressure chamber of a brake booster; a VSV that selectively renders the ejector operational or non-operational; and an ECU that controls the VSV. The ECU includes a blockage determining portion that determines whether there is a blockage in the ejector system according to a difference in the pressure in the negative pressure chamber and the pressure provided from the intake passage.

Abstract: A secondary air induction system (1) for an internal combustion engine of a motor vehicle, including a turbine (2) and a compressor (3), in which a turbine wheel (4) of the turbine (2) and a compressor wheel (5) of the compressor (3) are mounted on a rotatable common shaft (6) supported by a bearing assembly (8) including at least one roller bearing (17) inside a turbocharger housing (7). An insulating or noise damping material (9) externally encloses at least a portion of the housing (7) to provide sound insulation in the area of the bearing assembly (8).

Abstract: There is provided a pneumatic booster having an ejector, which achieves space-saving and enables easy piping. An ejector 4 is provided within a constant-pressure chamber 3 formed in an outer shell 2. A connecting pipe 19 communicated with an outlet of a diffuser and a connecting pipe communicated with an inlet of a nozzle extend outward of the shell, and a suction port is open to the inside of the constant-pressure chamber 3 through a check valve. The connecting pipe 19 is communicated with the constant-pressure chamber 3 through a check valve 10, and is connected to a suction pipe of an engine (a source of a negative pressure). The connecting pipe on the inlet side of the nozzle is connected to an air cleaner (the atmosphere). A negative pressure is directly supplied from the connecting pipe 19 to the constant-pressure chamber 3 through the check valve 10. The ejector 4 is operated to supply a high degree of vacuum to the constant-pressure chamber 3 through the suction port.

Abstract: A method and an apparatus are described for the simultaneous adjustment of an air intake stream 24 of an internal combustion engine 10 and of a secondary air stream 21 into the exhaust system 12 of the internal combustion engine, the secondary air stream being produced by a compressor 20 which is driven by a turbine 18. The turbine 18 is housed in a bypass duct 16, the bypass duct being arranged parallel to a throttle valve 14 in the air intake tract 11 of the internal combustion engine. Thus the required amount of secondary air 21 is dependent upon the throttle valve setting. To create compensation for this, a control valve 32, for example, is created, which is connected through a connecting duct 4 to the secondary air duct 22.

Abstract: Described are a method, a computer program, and a control unit for operating a vacuum reservoir provided in an internal combustion engine of a motor vehicle for a servo booster or power-assist unit of the internal combustion engine, which is coupled to an intake manifold of the internal combustion engine and to an electrical suction pump. The pressure prevailing in the vacuum reservoir is determined by a computational model in which quantity flows are fed to the vacuum reservoir when at least one servo unit is actuated, quantity flows are removed from the vacuum reservoir when the pressure prevailing in the intake manifold is lower than the pressure prevailing in the vacuum reservoir, i.e., when the electrical suction pump is switched on. The total pressure prevailing in the vacuum reservoir is calculated from the balance of these flow quantities.

Abstract: A braking device, particularly for a motor vehicle, comprising a master cylinder (10) associated with a pneumatic booster (12), and a vacuum pump (36) to create a vacuum in the vacuum chamber (16) of the booster, characterized in that the vacuum pump (36) is fixed to the envelope (14) of the booster on the inside of the latter within the vacuum chamber (16).

Abstract: This invention provides a manual boost control valve for an automotive turbocharger. The valve communicates between the intake side and exhaust side of the turbocharger system and particularly communicates with a wastegate actuator that operates a wastegate at the exhaust side. The wastegate actuator operates the wastegate in accordance with the degree of airflow received through the valve, and the valve may be manually manipulated from within the interior of the automobile by a knob interconnected through a cable to a restriction coupling.

Abstract: There is disclosed a pneumatic booster having a vacuum chamber connected to an intake pipe of an engine. An air outlet of an ejector is connected to the intake pipe through a vacuum control valve, and an air inlet of the ejector is connected to an air cleaner. A vacuum pick-up port of the ejector is connected to the vacuum chamber of a booster body. The vacuum control valve comprises a control chamber and a control piston, and the negative pressure in the booster is introduced into the control chamber and acts on the control piston. When the negative pressure in the booster is insufficient, the control piston acts to open the control valve and a negative pressure is supplied from the ejector to the vacuum chamber. When the negative pressure in the booster is sufficiently high, the control piston acts to close the control valve and stops the operation of the ejector, thus reducing an effect of the ejector with respect to an air/fuel ratio of the engine.

Abstract: A manifold assembly for pneumatically interconnecting a brake booster to an engine and to an electrically-driven vacuum pump. A manifold housing has an engine port pneumatically communicable with the engine, a separate booster port pneumatically communicable with the brake booster, and an orifice pneumatically communicable with the vacuum pump inlet. An engine check valve substantially blocks pneumatic flow from the engine port to the booster port. A vacuum-pump check valve substantially blocks pneumatic flow from the engine port to the vacuum pump outlet.

Abstract: A throttle loss recovery turbine and supercharger device (10) comprises a housing (12) having a movable intake port (36) and a separately movable exhaust port (38). An outer drum is rotatably placed within the housing. An inner drum (24) is rotatably disposed within the housing, and within an inside diameter of the outer drum (18). The inner drum has an axis of rotation (30) eccentric to an axis of rotation of the outer drum, defining a variable volume annular space (26) therebetween. The inner and outer drum are configured to rotate within the housing at a 1:1 ratio with one another, and the intake and exhaust ports are each in air flow communication with some portion of the annular space. A number of vanes (20) are each interposed radially between the inner and outer drums. Each vane is pivotably attached at one end (22) to the outer drum, and is attached at an opposite end to the inner drum. At least one drum is coupled to an engine crankshaft.

Abstract: A manifold assembly for pneumatically interconnecting a brake booster to an engine and to an electrically-driven vacuum pump. A manifold housing has an engine port pneumatically communicable with the engine, a separate booster port pneumatically communicable with the brake booster, and an orifice pneumatically communicable with the vacuum pump inlet. An engine check valve substantially blocks pneumatic flow from the engine port to the booster port. A vacuum-pump check valve substantially blocks pneumatic flow from the engine port to the vacuum pump outlet.

Abstract: A system or method for compensating for low vacuum levels in a brake-by-wire system includes continually monitoring the level of vacuum in a vacuum booster. The state or condition of the vacuum source is also monitored to determine whether it is on or off. When the vacuum source is off, the level of vacuum is measured to determine whether it is at or below a critical level. If the level of vacuum is critically low, the vacuum source is turned on. If the vacuum level is not critically low, the hydraulic boost gain is modified in order to provide more braking pressure in response to brake force exerted at the brake pedal.

Abstract: In an arrangement for producing a vacuum in a motor vehicle system including an internal combustion engine with an air intake system, a vacuum-operated power brake system for braking the vehicle and a fuel vapor adsorption system for collecting fuel vapors, a vacuum pump is provided which has a suction side in communication selectively with the vacuum operated power brake system and the fuel vapor adsorption system and a discharge side in communication with the air intake system of the internal combustion engine.

Abstract: An internal combustion engine in combination with a rotary positive displacement fluid machine. The combination having a rotor eccentrically mounted in a casing with a plurality of vanes defining compartments within the casing which vary in volume as the rotor rotates. Each vane is connected to a linkage to cause the vane, during rotation of the rotor, to pivot radially outwardly such that the outermost extremity of each vane is constrained to follow closely the internal wall of the casing. The linkage being constrained to follow at least one track in a member rotatable upon the same axis as the casing. The machine being connected to an air inlet manifold of the engine, and to atmosphere, such that the rotor is driven by the pressure difference between ambient air and air at the inlet manifold. The machine also is operatively connected to an energy using device.

Abstract: A self contained, supplemental vacuum assist unit is provided for use with a vacuum brake booster and a source of vacuum in a motor vehicle. The unit includes, within a single housing, an electric motor, an air pump driven by the motor, a manifold defining air exhaust and assist vacuum chambers, a pair of check valves permitting air flow from the pump outlet and the assist vacuum chamber to the air exhaust chamber, an outlet from the air exhaust chamber with a fitting for connection to the vacuum source, an opening from the assist vacuum chamber with a fitting providing communication directly to the interior of the vacuum chamber of the booster, and a pressure sensor including a diaphragm, plunger, magnet with a Hall effect sensor and motor control circuitry on a circuit board within the assist vacuum chamber. The unit is compact, light weight and efficient and is designed for attachment directly to the booster with no intervening vacuum hose therebetween.

Abstract: In order to provide a brake booster negative pressure controller which reduces deterioration in the fuel consumption due to operation for closing a throttle to assure a brake booster negative pressure while assuring the braking capability required according to driving conditions and can safely assure a braking capability even when a failure occurs in a negative pressure sensing system, said brake booster negative pressure controller comprises a brake booster for assuring a master vac negative pressure by using a negative pressure of an engine, a throttle valve whose opening angle can be operated independently from the stroke of an accel pedal, and a brake operation sensing means, wherein the negative pressure controller has a speed sensing means and a means for closing the throttle valve by a predetermined amount when the vehicle speed sensed by the vehicle speed sensing means is equal to or higher than a predetermined value and application of the brake is sensed by the brake operating sensing means.

Abstract: A brake booster provides additional boost capacity without unduly increasing booster size and weight by providing a vacuum pump connected so as to add its additional vacuum capacity to that of the normal vacuum source when activated in response to sensed approaching run-out. The additional vacuum is provided by connecting the vacuum pump in a second conduit between the vacuum source and the booster vacuum chamber in parallel with a first conduit connecting the vacuum source directly with the booster vacuum chamber, with check valve means in the first and second conduits preventing substantial vacuum loss from the vacuum chamber.

Abstract: In an arrangement for producing a vacuum in a motor vehicle system including an internal combustion engine with an air intake system, a vacuum-operated power brake system for braking the vehicle and a fuel vapor adsorption system for collecting fuel vapors, a vacuum pump is provided which has a suction side in communication selectively with the vacuum operated power brake system and the fuel vapor adsorption system and a discharge side in communication with the air intake system of the internal combustion engine.

Abstract: A negative pressure control apparatus for a brake booster for controlling a negative pressure in a negative pressure chamber of the brake booster is provided. The apparatus is applied to a system having a booster charge mechanism for generating a fluid pressure by using the negative pressure in the negative pressure chamber and a fluid pressure control mechanism for controlling a brake fluid pressure by using the fluid pressure generated by the booster charge mechanism as a fluid pressure source. The apparatus includes a negative pressure controller for controlling the negative pressure in the negative pressure chamber to be at least a predetermined target negative pressure. A temperature detector detects information relating to a temperature of brake fluid. A target negative pressure setting part sets the predetermined negative pressure based on the temperature of the brake fluid.

Abstract: A rotary machine has a rotor eccentrically mounted in a casing and having a plurality of vanes connected to oscillating arms via cranks, the cranks having elements pivotally embracing a radial outer end of the arms. The arms can be radial. The rotor has outer axial parts connected to an intermediate part by grooves and rings resisting radial expansion. The rotary machine can be used in a fuel-injected engine for example to derive energy from the difference in air pressure between ambient and the inlet manifold.

Abstract: The invention relates to a method for controlling an internal combustion engine of a motor vehicle having an auxiliary force brake device wherein the auxiliary force is generated by coupling the brake actuation to the manifold pressure of the engine. In the method, the engine is operated with increased manifold pressure during the warm-up phase after a cold start. In the method, an actuation of the brake effects limiting the manifold pressure to a maximum value by intervening in the engine control. This maximum value is less than the value which would otherwise adjust under the same conditions without brake actuation.

Abstract: A secondary air system for an internal combustion engine (32), including at least one line (14) through which air is blown into the exhaust pipe of the engine, a pump (26) and a drive (27) for the pump (26). In addition an air-feed line (13) is provided through which the secondary air is supplied to the pump (26). The power necessary to drive the pump is provided by the engine (32).

Abstract: A brake booster having a body in which a booster pressure sensor for detecting the internal pressure of an atmospheric pressure chamber is provided, and in which the operating state of a brake pedal is detected by a pedal sensor. Further, when the brake pedal is not depressed, the internal pressure of the negative pressure chamber is detected by the booster pressure sensor. In contrast, when the brake pedal is depressed, an atmospheric pressure is detected by the same booster pressure sensor. Namely, when the brake pedal is not depressed, the negative pressure chamber and the atmospheric pressure chamber communicate with each other and are thus shut off from atmospheric air. Therefore, the internal pressure of the negative pressure chamber is detected by the booster pressure sensor which communicates with the atmospheric pressure chamber. Moreover, when the brake pedal is depressed, the atmospheric pressure chamber communicates with atmospheric air.

Abstract: A brake system of an engine comprising a brake booster. A restricted portion is formed in an intake passage upstream of a throttle valve and mass flow meter. A vacuum takeout port opens in the restricted portion. The vacuum generated in the restricted portion is led through a check valve to the brake booster. At the time of operating of the brake booster, the air ejected from the vacuum takeout port is measured by the mass flow meter as part of the intake air.

Abstract: A vacuum back-up system for diesel vehicles, and a primary vacuum system for high performance vehicles, which vacuum system includes a vacuum pump for creating a vacuum in an associated reserve vacuum tank connected to the vacuum booster of the vehicle. A relay is attached to the vacuum pump or to a mount bracket which mounts the vacuum pump and the reserve vacuum tank and the relay is electrically connected to a vacuum switch on the vacuum booster and to the vehicle battery and the vacuum pump to facilitate operation of the vacuum pump and maintaining a vacuum of preselected magnitude in the reserve vacuum tank and the vacuum booster.