Abstract:
A hydraulically operated charge air system for an internal combustion engine includes an intake manifold having a number of intake runners, and a number of rotatable airflow control devices mounted within at least a portion of the intake runners. A hydraulic motor rotatably positions the airflow control devices.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    None. 
       BACKGROUND OF THE DISCLOSURE 
       [0002]    1. Field of the Disclosure 
         [0003]    The present disclosure relates to a charge air system for an internal combustion engine having a hydraulically operated airflow control capability associated with the engine&#39;s intake manifold. 
         [0004]    2. Related Art 
         [0005]    Devices for controlling the flow of charge air within an intake manifold have typically used either vacuum or electrical power. Each of these types of power source is characterized by certain shortcomings. In the case of vacuum devices, vacuum availability under some operating conditions, such as operation at high altitude, may be a problem. In the case of electrical devices, package space and reliability present issues. Moreover, with both types of systems, failure mode management may be an issue. Excessive noise, and, in the case of electrical devices, electromagnetic compatibility, may also be issues, as is high cost, it being understood that cost reduction is a never ending goal in the automotive design field. 
         [0006]    It would be desirable to provide an internal combustion engine charge air system having airflow control devices which overcome the difficulties associated with electrical and vacuum powered devices, while avoiding excessive cost. 
       SUMMARY 
       [0007]    According to an aspect of the present disclosure, a hydraulically operated charge air system for an internal combustion engine includes an intake manifold having a number of intake runners and a number of rotatable airflow control devices mounted within at least a portion of the intake runners. A hydraulic motor rotatably positions the airflow control devices according to instructions from either a controller which contains a predetermined control strategy, or as a function of engine oil pressure, independently of a controller. For example, a hydraulic motor positioning airflow control devices used with long/short runner control may be operated according to an engine&#39;s speed and load. 
         [0008]    According to another aspect of the present disclosure, an intake manifold may have a number of short intake runners and a number of long intake runners, with rotatable airflow control devices being configured as intake runner control valves mounted within the short intake runners. 
         [0009]    According to another aspect of the present disclosure, rotatable airflow control devices may include charge motion control valves, particularly valves having a control area which is less than the flow area of the intake runner within which the valve plate is mounted. In either case, rotatable airflow control devices will be mounted upon a rotatable shaft which is coupled to the hydraulic motor. 
         [0010]    According to another aspect of the present disclosure, the hydraulic motor may be powered by an engine lubrication pump, with the motor including a housing and a multi-lobed rotor rotatably positioned within the housing so that engine oil passing through appropriate control ports will cause the rotor to position the airflow control devices in a desired rotational location. 
         [0011]    It is an advantage of the present system that the package volume required for the system will be less than that required for known pneumatic or electrodrive systems. 
         [0012]    It is a further advantage of the present system that problems with electromagnetic compatibility and audible noise are eliminated. 
         [0013]    It is yet another advantage of the present system that the response speed is very high due to the operating principles of the hydraulic motor which positions the flow control devices. 
         [0014]    It is yet another advantage of the present system that the cost for a charge air system is low compared to known vacuum and electrically driven devices. 
         [0015]    Other advantages, as well as features of the present system, will become apparent to the reader of this specification. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a schematic representation of an internal combustion engine having a hydraulically operated charge air system according to the present disclosure. 
           [0017]      FIG. 2  is a perspective view of a portion of an intake manifold according to the present disclosure, showing the inventive hydraulically operated charge air system. 
           [0018]      FIG. 3  is a partially schematic view of a hydraulic motor used with the present charge air system. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0019]    As shown in  FIG. 1 , a hydraulically operated charge air system,  10 , is mounted to an engine,  14 , having cylinder head  16 , cylinders,  18 , equipped with intake valves,  22 , and exhaust valves,  26 , as well as spark plugs,  30 . A throttle plate,  34 , which is mounted to intake manifold  36 , governs the amount of air entering engine  14 . Air flowing past throttle plate  34  enters a first plenum,  38  and a second plenum,  42 . Long intake runners,  46 , extend from first plenum  38  to cylinders  18 , and short intake runners,  50 , extend from plenum  42  to cylinders  18 . An airflow control device, shown as a runner control valve,  58 , in  FIG. 1 , is mounted in each of short intake runners  50 . The position of runner control valves  58  is controlled by hydraulic motor  66 , which is operated by controller  64 , and provided with pressurized lubricating oil through cylinder head  16  by engine oil pump  86 . 
         [0020]      FIG. 2  shows a rotatable control shaft,  54 , as being mounted in close proximity to intake manifold mounting flange  78 . In the embodiment of  FIG. 2 , a charge motion control valve (CMCV) plate,  62 , is mounted within each of the runners  52 .  FIG. 2  also shows hydraulic motor  66 , including housing  80  and rotor  70  having two vanes,  74 , mounted thereupon. A torsion spring,  84 , is used to drive rotatable control shaft  54 , including CMCV plate,  62 , to its closed position when oil pressure is not supplied, as well as in the event of a loss of control strategy. Those skilled in the art will appreciate in view of this disclosure that a single engine could be equipped with not only runner control valves, but also charge motion control valves, with both types of valves operated according to the present disclosure. 
         [0021]      FIG. 3  shows additional details of hydraulic motor  66 , including an oil feed passage,  82 , and a return passage,  83 , which communicate with oil passages (not shown) provided within cylinder head  16 . Oil feed passage  82  is selectively provided with pressurized engine oil which flows into upper chamber  89 , so as to cause rotor  70  to rotate counterclockwise to a desired location for a CMCV or runner control valve, as the case may be. Passage  87  allows oil to flow through rotor  74  to lower chamber  90 . When passage  83  is opened, oil is allowed to leave chambers  89  and  90 , and torsion spring  84  drives vane  74  and control shaft  54  to the closed position. 
         [0022]    Those skilled in the art will appreciate in view of this disclosure that rotor  70  could be configured with more than two lobes, alternatively, rotor  70  could be equipped with a single lobe; such details are committed to the discretion of those seeking to employ the present system. Moreover, the present system may be employed with engines having configurations which are different from that shown in  FIG. 1 . 
         [0023]    Vanes  74  of rotor  70  have an included angle of about 140°, which is configured in order to match the maximum rotation of rotor  70  to the valve plate opening angle. Vanes  74  could have a range of included angles therebetween. Advantageously, hydraulic motor  66  does not extend past the parting line between cylinder head  16  and intake manifold  36 . 
         [0024]    Airflow control device  62  is illustrated in  FIG. 2  as having a control area which approximates about seventy-five percent of the flow area of intake runner  52  at the location in which device  62  is mounted. Those skilled in the art will appreciate in view of this disclosure, however, that other types of CMCV devices may be suitable for use with the present system, it being clear that the illustrated device is merely an example of a whole range of such devices. 
         [0025]    The foregoing system has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiments may become apparent to those skilled in the art and fall within the scope of the disclosure. Accordingly the scope of legal protection can only be determined by studying the following claims.