Vacuum reservoir

An intake manifold with vacuum storage for a vehicle engine defined by an integrally formed enclosure assembly for the manifold and for the vacuum storage. The intake manifold portion of the enclosure assembly defines a plenum space and a plurality of branch runners fluidly connected to an air inlet for providing air flow into the associated engine. The vacuum storage portion of the enclosure assembly defines a storage space for vacuum. A passageway extends between the plenum space and the vacuum storage space and a check valve is provided therein to allow air flow from the vacuum storage space into the plenum space to block air flow from the plenum space into the vacuum storage space.

FIELD OF THE INVENTION
 The field of the present invention is that of intake manifolds for an
 internal combustion engine.
 DESCRIPTION OF PRIOR ART
 For sometime, efforts have been made to increase the fuel economy of
 automotive vehicles. To achieve increased fuel economy, several technical
 trends have developed. One technical trend which has been utilized to
 increase fuel economy is to utilize smaller V-6 or inline 4 cylinder
 engines instead of V-8 engines. Still another technical trend to increase
 fuel economy is to make the vehicle lighter.
 One example of how an automotive component can be made lighter is intake
 manifolds formed from plastics. These new manifolds can withstand high
 temperatures and can be injection molded or blow molded. Previously, many
 if not most of automotive intake manifolds were made from cast aluminum.
 The majority of vehicles have at least two or three components which are
 vacuum actuated. Vacuum actuated components include vacuum assistant power
 brake boosters and other components such as cruise control or secondary
 manifold runner valves (typically utilized on some high performance
 vehicles). Additionally, other components are vacuum actuated such as many
 of the gate values actuators in the heating, ventilation and air
 conditioning system of the vehicle.
 The suction action of an engine piston reciprocating in a cylinder of an
 internal combustion engine is typically how vacuum is generated. This
 vacuum capacity is relied upon in many applications in an automotive
 vehicle. The aforementioned trend from large V-8 engines with large
 displacement to smaller 4 or 6-cylinder engine much smaller displacements
 has decreased the potential generation of large amounts of vacuum. Vacuum
 capacity is especially diminished when a small displacement engine is
 operating at open throttle conditions. According, vacuum storage
 accumulators (commonly referred to as vacuum reservoirs) have been added
 to many vehicles to collect vacuum power when available for associated
 vacuum actuated components. A check valve is provided between the engine
 manifold and the vacuum reservoir to retain vacuum in the reservoir until
 needed. The check valve cuts off fluid connection between the vacuum
 reservoir in the manifold when the pressure level in the manifold
 increases due to operation under partial or open throttle conditions.
 Typically, a vacuum hose line is used to connect the manifold and the
 reservoir. Another vacuum hose line is required between the vacuum
 reservoir and the vacuum actuated component. Due to engine compartment
 crowding, the reservoir is often remotely located. Also, vacuum lines are
 often placed in vary inconvenient places and routes. Leaks in vacuum hoses
 can often be very hard to diagnose and very often lead to undesirable
 engine operation.
 It would be highly desirable to consolidate the vacuum reservoir and vacuum
 producer. It would be highly desirable to minimize the vacuum hoses
 required to deliver vacuum to a vacuum reservoir. It would be highly
 desirable to eliminate the cost of the bracketing required for affixing a
 vacuum reservoir to the vehicle engine block or to car body.
 SUMMARY OF THE INVENTION
 In a preferred embodiment of the present invention, an engine intake
 manifold is combined with a vacuum reservoir. The intake manifold
 typically has an inlet passage for receiving filtered ambient air thereto
 and a plenum space which is then connected to a plurality of branches or
 runner passages for conducting air flow to the various engine combustion
 chambers. A vacuum reservoir is integrally formed with the plenum and
 separated therefrom by an integral wall of the manifold. A passage is
 formed through the integral wall to allow withdrawal of air from the
 reservoir to the manifold interior for creating a vacuum condition
 therein. The vacuum reservoir has an outlet which acts to apply a vacuum
 effect to any of the vehicle's several vacuum operated components.
 Additionally, a check valve is provided between the manifold interior and
 the reservoir interior. The check valve allows a one-way flow of air from
 the vacuum reservoir to the manifold plenum but does not permit flow from
 the manifold into the reservoir. The check valve permits a flow of air
 from the reservoir into the manifold's plenum when the engine is operated
 in a closed or near closed throttle condition which generates vacuum in
 the intake manifold. The check value prevents air flow from the manifold's
 plenum back into the reservoir when the engine is operated in an open or
 mostly open throttle condition which does not generate vacuum in the
 intake manifold.
 It is an object of the present invention to provide an integral manifold
 and vacuum reservoir for an automotive engine.
 It is a further object of the present invention to provide an automotive
 engine intake manifold assembly having an integral vacuum reservoir which
 assembly can be fabricated from a clam shell polymeric material which is
 then sonically welded together.
 The above noted and other objects of the present invention will become
 apparent to those skilled in the art from a review of the invention as
 provided in the accompanying drawings and detailed description of a
 preferred embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
 FIG. 1 illustrates a preferred embodiment of the subject intake manifold 10
 according to the present invention. The manifold is normally attached to
 an automotive engine, specifically a cylinder head thereof (not shown).
 Reciprocating pistons in the engine create a suction action which draws
 air from the manifold into combustion chambers of the engine. This action
 is useful to create a vacuum which can then be used for associated vacuum
 powered components of the vehicle.
 The intake manifold 10 may be a cast metallic member or may be molded of a
 polymeric material. In the illustrated example, the material utilized is a
 nylon plastic material typically supplied by Dupont of Troy, Michigan. The
 nylon material can withstand temperatures of 300 degrees F and typically
 will be injection molded with a 2 to 3 millimeter wall thickness. As
 shown, the manifold 10 has a clam shell type construction an upper and a
 lower half 30, 32 respectively. The two halves are sonically or vibration
 welded together.
 The manifold 10 has an inlet end forming a channel 36. The inlet 36 is
 connected with an outlet of an air filter assembly (not shown) which is
 typically used in vehicles to screen-out dirt and foreign matter from the
 ambient air. A typical inlet channel 36 will have a three square inch area
 opening. Fluidly connected with the inlet channel 36 is a plenum space
 formed within housing 40. The plenum housing 40 provides a volume for
 engine air typically at least 1.2.times. the engine displacement. Fluidly
 connected with the plenum space are a series of four branch runners 42,
 44, 46 and 48 (for a four cylinder engine). The runners 42, 44, 46 and 48
 are formed and arranged so as to provide a smooth air flow to each of the
 engine combustion chambers characterized by equal conditions of volumetric
 flow rate and pressure. Normally, each branch runner delivers 10,500 to
 105,000 cubic inches of air per minute to a combustion chamber. At a
 closed throttle conditions the vacuum within the interior of the plenum 40
 typically range from 19 to 25 mmHg.
 Referring to FIG. 2, a vacuum reservoir 50 is formed integrally with the
 intake manifold channel forming portion and plenum housing 40. The vacuum
 reservoir 50 is integrally molded with the intake manifold 10 and
 particularly the plenum housing 40. A typical vacuum reservoir 50 has a 50
 cubic inch volume. A passageway 60 is located between the vacuum reservoir
 50 and the plenum 40. Passageway 60 supports a check valve assembly 62
 therein. Assembly 62 may be inserted into the passageway or attached
 therein. The check valve assembly is generally cylindrical and has an
 inner wall 64 which his apertured by bore or flow passage 66. A flexible
 flapper member 68 is located on the rightward or reservoir side of wall
 64. The flapper member 68 has a freely movable edge portion 70 and hinged
 edge portion 72.
 When the intake manifold 10 is being used with an active internal
 combustion engine under closed (idle) or near closed throttle conditions,
 the movement of the pistons in the engine cylinders creates a suction and
 subatmospheric condition (vacuum) in the interior of the manifold. The
 vacuum condition from each cylinder is communicated to the interior 40' of
 the plenum housing 40 through the four branch runners 42, 44, 46 and 48.
 The vacuum condition in plenum interior 40' causes the freely movable edge
 portion 70 of flapper 68 to the left in FIG. 2 which opens the flow
 passage 66 to allow air to flow therethrough from the interior 50' of
 reservoir into the interior 40' of the manifold 40. This generates a
 subatmospheric condition or a vacuum within the reservoir interior 50'. In
 a typical application of the present invention, when the engine is idled
 (throttle effectively closed), the level of vacuum in the plenum can
 approach about 19-25 mmHg and when vacuum using components are not active
 the vacuum in the interior 50' can also reach about 19-25 mmHg. However,
 as various vacuum actuated components are actuated, air will flow into the
 interior 50' of the reservoir 50 via a connecting hose (not shown) and
 through the nipple-like fitting 82. In the illustrated example, there is
 only one fitting 82. However, it will be obvious to those skilled in the
 art that a multitude of fittings can also be provided. In fact, many
 vehicle embodiments prefer to provide a separate fitting feed only the
 brake vacuum booster and to provide another fitting for all the other
 components combined.
 As the engine's throttle is opened, the vacuum level within the plenum 40
 decreases. Under these conditions, the vacuum level within the reservoir
 may exist at a greater level than the vacuum level within the plenum 40
 (meaning at a lower subatmospheric pressure). When this occurs, the freely
 movable lower edge portion 70 of the flapper 68 is urged to the right as
 shown in FIG. 2 to block passage 66 which isolates the interior 50' of the
 reservoir 50 from the interior 40' of the manifold plenum 40. If
 desirable, the material and configuration of the check valve 62 can be
 selected to perform at a different pressure differential cut-off point for
 accommodating various manifolds or different vehicle vacuum component
 options.
 The present vehicle intake manifold with its integral vacuum reservoir has
 been shown in a preferred embodiment. However, it will be apparent to
 those skilled in the art, the various modifications can be made to the
 present invention without departing from the spirit or scope of the
 present invention as it is an encompassed in the specification and
 drawings and by the following claims.