Abstract:
A system for supplying compressed air to an engine is presented. In one embodiment, the system includes a cylinder block that forms at least part of an air compressor housing. The system may improve engine balance and reduce engine assembly cost.

Description:
FIELD 
       [0001]    The present description relates to a system for supplying pressurized air to an internal combustion engine. The system may be useful for improving engine balance and reducing engine assembly costs. 
       BACKGROUND AND SUMMARY 
       [0002]    Engines may be supercharged to improve engine performance and to extend the dynamic operating range of the engine. Superchargers pressurize air entering the engine by way of a compressor, thereby increasing the amount of air available to the engine. The compressor of a supercharger may be configured with meshing lobes or a centrifugal pump. In U.S. Pat. No. 6,227,179 a supercharger is coupled to engine cylinder heads by way of intake passages that are fed air from an intercooler located downstream of the supercharger. The described supercharger is purported to offer ease of assembly, small packaging, and nimble response. However, bolting a supercharger to the top of an engine may result in alignment issues between the compressor pulley and the engine drive pulley. As such, the compressor may degrade engine balance. Further, coupling the compressor above and away from the engine may limit engine speed since the effective engine inertia is increased by moving the rotating mass away from the crankshaft. Further still, it appears that hoses are required to supply coolant to the intercooler thereby increasing the possibility for developing a coolant leak. 
         [0003]    The inventor herein has recognized the above-mentioned disadvantages and has developed a system for improving a supercharged engine. 
         [0004]    One embodiment of the present description includes a system, comprising: an engine block having a plurality of cylinders for housing a plurality of pistons, said engine block contiguous with at least a portion of a supercharger air compressor housing, said supercharger air compressor housing having an inlet for fresh air and an outlet that provides compressed air to cylinders in said cylinder block; and a cylinder head receiving air from said supercharger air compressor housing. 
         [0005]    By forming at least a portion of a supercharger air compressor housing from an engine block, it may be possible to improve engine balance, reduce engine inertia, and lower the possibility of coolant leaks. For example, a supercharger constructed in the valley of a V engine may reduce engine inertia, lower engine assembly cost, improve engine balance, and reduce the number of engine hose connections. In one example, the rotors or scrolls of a supercharger may be placed in the valley of a V engine between engine cylinders. Moving the compressor scrolls closer to the engine crankshaft can reduce engine inertia and improve engine balance since the compressor scroll mass is located closer to the rotational mass of the crankshaft. In addition, when an intercooler coupled to the compressor housing is supplied coolant from the engine block or cylinder heads, the number of hose connections of the engine may be reduced, thereby reducing the possibility of coolant leaks. 
         [0006]    The present description may provide several advantages. For example, the approach may reduce engine inertia and improve engine balance. Further, the approach may reduce the possibility of coolant leaks. Further still, the approach may reduce engine costs since the supercharger can be machined at the same time that the engine block is being machined. 
         [0007]    The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings. 
         [0008]    It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The advantages described herein will be more fully understood by reading an example of an embodiment, referred to herein as the Detailed Description, when taken alone or with reference to the drawings, where: 
           [0010]      FIG. 1  is a schematic diagram of an engine; 
           [0011]      FIG. 2  shows front view of an eight cylinder engine block; 
           [0012]      FIG. 3  shows a plan view of an eight cylinder engine block; 
           [0013]      FIG. 4  shows a plan view of an intercooler for a compressor that is integrated into an engine block; 
           [0014]      FIG. 5  shows a cross section of an intercooler for a compressor that is integrated into an engine block; 
           [0015]      FIG. 6  shows a front view of an intake manifold for supplying air to engine cylinders; 
           [0016]      FIG. 7  shows a plan view of the bottom of an intake manifold for supplying air to engine cylinders; and 
           [0017]      FIG. 8  is a flow chart for supplying air to cylinders of an engine having a compressor housing that is at least partially integrated into an engine block. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    The present description is related to an engine block with a compressor housing. In one non-limiting example, the engine block may be configured as illustrated in  FIGS. 1-3 . Further, the compressor may supply compressed air to an intercooler and intake manifold as shown in  FIGS. 4-7 . Finally, a method for supplying compressed air to an engine block with a compressor housing is described by  FIG. 8 . 
         [0019]      FIG. 1  shows a schematic depiction of an example engine system  100  including a multi-cylinder internal combustion engine  110  having an integrated compressor housing  36 . As one non-limiting example, engine system  100  can be included as part of a propulsion system for a passenger vehicle. Engine system  100  can receive intake air via intake passage  140 . Intake passage  140  can include an air filter  156 . 
         [0020]    Air travels through intake passage  140  and encounters throttle  149  before entering intake passage  149 . In some examples, intake passage  149  may part of engine block  101 . Air entering intake passage  149  is directed into the bottom of compressor housing  36 . At least a portion of compressor housing  36  is an integral portion of engine block  101 . Compressor lobes or scrolls  35  compress air before directing air to intercooler  55 . Compressor lobes separate an upper section of compressor  37  from a lower section of compressor  37 . The lower section of compressor  37  contains uncompressed air for supplying engine cylinders. The upper section of compressor  37  may contain air compressed by scrolls  35 . Air from compressor  37  is directed to intercooler  55  and then to intake manifold  160  before entering engine cylinders  20 A and  20 B. Intake manifold  58  may include an intake manifold pressure sensor (not shown) and/or an intake manifold temperature sensor (not shown), each in communication with control system  190 . Intake passage  149  can include also include a pressure sensor. The position of throttle  158  can be adjusted by control system  190  via throttle actuator  157  communicatively coupled to control system  190 . A bypass valve may be included between intake passage  149  and intake manifold  160  to bypass compressor  37 . Thus, throttle  158  is positioned upstream of compressor  37 . Further, compressor  37  is located upstream of intercooler  55 , and intercooler  55  is located upstream of intake manifold  58 . 
         [0021]    Engine  110  may include a plurality of cylinders two of which are shown in  FIG. 1  as  20 A and  20 B in cylinder block  101 . Note that in some examples, engine  110  can include more than two cylinders such as 4, 5, 6, 8, 10 or more cylinders. These various cylinders can be equally divided and arranged in a V configuration in-line with one of cylinders  20 A and  20 B. Cylinders  20 A and  20 B among other cylinders of the engine may be identical in some examples and include identical components. As such, only cylinder  20 A will be described in detail. Cylinder  20 A includes a combustion chamber  22 A defined by combustion chamber walls  24 A. A piston  30 A is disposed within combustion chamber  22 A and is coupled to a crankshaft  34  via a crank arm  32 A. Crankshaft  34  may include an engine speed sensor  181  that can identify the rotational speed of crankshaft  34 . Engine speed sensor  181  can communicate with control system  190  to enable a determination of engine speed. Cylinder  20 A can include a spark plug  70 A for delivering an ignition spark to combustion chamber  22 A. However, in some examples, spark plug  70 A may be omitted, for example, where engine  110  is configured to provide combustion via compression ignition. Combustion chamber  22 A may include a fuel injector  60 A, which in this example is configured as a port based fuel injector. However, in other examples, fuel injector  60 A can be configured as a direct in-cylinder injector. 
         [0022]    Cylinder  20 A can further include at least one intake valve  40 A actuated via an intake valve actuator  42 A and at least one exhaust valve  50 A actuated via an exhaust valve actuator  52 A as part of cylinder head  105 . Cylinder  20 A can include two or more intake valves and/or two or more exhaust valves along with associated valve actuators. In this particular example, actuators  42 A and  52 A are configured as cam actuators, however, in other examples, electromagnetic valve actuators (EVA) may be utilized. Intake valve actuator  42 A can be operated to open and close intake valve  40 A to admit intake air into combustion chamber  22 A via intake manifold  58 . Similarly, exhaust valve actuator  52 A can be operated to open and close exhaust valve  50 A to exhaust products of combustion from combustion chamber  22 A into exhaust passage  166 . In this way, intake air may be supplied to combustion chamber  22 A via intake manifold  58  and products of combustion may be exhausted from combustion chamber  22 A via exhaust passage  166 . 
         [0023]    It should be appreciated that cylinder  20 B or other cylinders of engine  110  can include the same or similar components of cylinder  20 A as described above. For example, fuel injector  60 B, intake valve actuator  42 B, and exhaust valve actuator  52 B. Thus, intake air may be supplied to combustion chamber  22 B via intake manifold  58  and products of combustion may be exhausted from combustion cylinder  20 B via exhaust passage  168 . Note that in some examples a first bank of cylinders including cylinder  20 A as well as other cylinders can exhaust products of combustion via a common exhaust passage  166  and a second bank of cylinders including cylinder  20 B as well as other cylinders can exhaust products of combustion via a common exhaust passage  168 . Further, oil pan  103  is coupled to engine block  101  for holding oil supplied to lubricate cylinders  20 A and  20 B. 
         [0024]    Products of combustion that are exhausted by engine  110  via exhaust passage  166  can be directed to atmosphere via exhaust passage  166 . Exhaust passage  166  may include an exhaust aftertreatment device such as catalyst  174 , and one or more exhaust gas sensors indicated at  184  and  185 , for example. Similarly, products of combustion exhaust by one or more cylinders via exhaust passage  168  can be directed to ambient. Exhaust passage  168  may include an exhaust aftertreatment device such as catalyst  176 , and one or more exhaust gas sensors indicated at  186  and  187 , for example. Exhaust gas sensors  184 ,  185 ,  186 , and/or  187  can communicate with control system  190 . 
         [0025]    Engine system  100  can include various other sensors. For example, at least one of intake passages  140  can include a mass air flow sensor (not shown). A mass airflow sensor may include, as one example, a hot wire anemometer or other suitable device for measuring mass flowrate of the intake air. 
         [0026]    Control system  190  can include one or more controllers configured to communicate with the various sensors and actuators described herein. As one example, control system  190  can include at least one electronic controller comprising one or more of the following: an input/output interface for sending and receive electronic signals with the various sensors and actuators, a central processing unit, memory such as random accessible memory (RAM), read-only memory (ROM), keep alive memory (KAM), each of which can communicate via a data bus. Control system  190  may include a proportional-integral-derivative (PID) controller in some examples. However, it should be appreciated that other suitable controllers may be used as can be appreciated by one skilled in the art in light of the present disclosure. 
         [0027]    Control system  190  can be configured to vary one or more operating parameters of the engine on an individual cylinder basis. For example, the control system can adjust valve timing by utilizing a variable cam timing (VCT) actuator, spark timing by varying the time at which the spark signal is provided to the spark plug, and/or fuel injection timing and amount by varying the pulse width of the fuel injection signal that is provided to the fuel injector by the control system. Thus, at least the spark timing, valve timing, and fuel injection timing can be actuated by the control system. 
         [0028]    Referring now to  FIG. 2 , a front view of a non-limiting eight cylinder V-8 engine block is shown. Cylinder block  101  includes cylinders  202  and  204 . Cylinder  202  is one of a plurality of cylinders in a first bank of cylinders. Likewise, cylinder  204  is one of a plurality of cylinders in a second bank of cylinders. Cylinder block  101  is a continuous piece of material and may be comprised cast iron, aluminum, ceramic, or other suitable material. 
         [0029]    A first side of engine block wall  206  is comprised of material that is continuous with material comprising engine cylinder  202  and crankshaft journal bearing support  230 . A second side of engine block wall  206  includes a portion of the wall that is at least a portion of an inside wall of air compressor  37 . Thus, engine block wall  206  is at least a portion of a housing of air compressor  37 . Engine block wall  206  extends from the bottom of the intersection of engine cylinder banks (e.g., the bottom of the V between engine cylinders) to cylinder deck  220 . Thus, compressor  37  shares a portion of engine block wall  206  with engine block material that supports a wall of cylinder  202 . A cylinder head (not shown) is coupled to cylinder deck  220 . 
         [0030]    Similarly, a first side of engine block wall  208  is comprised of material that is continuous with material comprising engine cylinder  204 . A second side of engine block wall  208  is at least a portion of an inside wall of compressor  37 . Thus, engine block wall  208  is at least a portion of a housing of air compressor  37 . In addition, engine block wall  206  and engine block wall  208  are part of a continuous piece of material forming engine block  101 . Thus, engine block wall  208  is at least a portion of a housing of air compressor  37 . Engine block wall  208  also extends from the bottom of the intersection of engine cylinder banks (e.g., the bottom of the V between engine cylinders) to cylinder deck  222 . A cylinder head (not shown) is coupled to cylinder deck  220 . 
         [0031]    Engine block wall  208  may also include a machined surface  212  on the inside of compressor  37  for sealing a lower section of the compressor housing from an upper section of compressor housing. Compressor lobes, scrolls, or rotors (not shown) and machined surface  212  seal a lower chamber of a housing of compressor  37  from an upper housing of compressor  37  that may contain pressurized air. 
         [0032]    In this example, the housing of compressor  37  includes a span  218  that links an area of engine block  101  between engine block wall  206  and engine block wall  208 . Span  218  is made of material that is continuous with material of engine block wall  206  and engine block wall  208 . Span  218  encloses an area between engine block wall  206  and engine block wall  208  enclosing an area formed by part of a housing of compressor  37 . Span  218  also includes an outlet opening  210  for transferring compressed air from compressor  37  to an intercooler (not shown). 
         [0033]    When compressor is completely assembled one or more rotors or scrolls (not shown) may be included as part of compressor  37 . Further, a front plate and a rear plate may be coupled to engine block  101  to seal a housing of compressor  37 . In an alternative embodiment, a front and rear section may be a continuous part of engine block  101 . The rotors or scrolls may be mounted to the front and rear plates such that the rotors can rotate within compressor  37  and move air from a lower section of compressor  37  (e.g., an area below the compressor scrolls) to an upper section of compressor  37  (e.g., an area above the compressor scrolls). The rotors may be driven by a chain from the crankshaft or by a gear set coupling the rotors to the crankshaft. Further, machining of surfaces  212  and  216  as well as rotor mounting journal supports may be referenced from engine block datum points. 
         [0034]    Engine block  101  also includes port  232  for evacuating gases from the engine crankcase. Flow from the engine crankcase is regulated by crankcase ventilation valve  234 . Thus, the engine crankcase can be ventilated directly to the compressor without the gases exiting the boundary of the engine. Ventilation valve  234  may be controlled mechanically or by a controller. 
         [0035]    Referring now to  FIG. 3 , a plan view of the top of an engine block is shown. In particular, the top of engine block  101  shown if  FIG. 2  is shown. Engine block  101  includes a cylinder  202  and cylinders  308  on the left side of engine block  101 . Engine block  101  also includes cylinder  202  and cylinders  306 . Engine block  101  also includes coolant ports  304  for cooing air passing though an intercooler (not shown) that is coupled to engine block  101 . In one embodiment, engine coolant may flow from one side of the engine block to the other side of the engine block through intercooler  55 . In another embodiment, engine coolant flow from the V area of the engine block to the intercooler. Compressor  37  also includes inlet  302  and outlet  210 . Air enters compressor  37  through inlet  302  and compressed air exits outlet  210  before entering an intercooler (not shown). Engine block  101  and material surrounding compressor inlet  302 , compressor outlet  210 , cylinder  202 , cylinders  308 , cylinder  204 , cylinders  306 , and coolant ports  304  is a single continuous piece of material. When fully assembled, compressor  37  includes scrolls or lobes for compressing air entering the compressor housing. In one non-limiting example, the material forming the engine block may be shaped by a casting. 
         [0036]    Referring now to  FIG. 4 , a plan view of an intercooler for cooling air supplied by a compressor that is part of a cylinder block is shown. In particular, a detailed view of intercooler  55  of  FIG. 1  is shown. Coolant tubes  406  hold coolant that flows from a first cylinder bank to a second cylinder bank. Coolant reduces the temperature of air compressed by compressor  37  of  FIGS. 1-3 . Metallic fins  404  link and support coolant tubes  406 . Further, fins  404  increase the surface area contact between compressed air and intercooler  55 , thereby improving heat transfer between compressed air and engine coolant. Intercooler  55  is coupled to engine block  101  at outlet  210  of compressor  37 .  FIG. 4  also shows the location of section A which is illustrated in  FIG. 5 . In some embodiments intercooler  55  may be omitted if desired. 
         [0037]    Referring now to  FIG. 5 , a cross section of an intercooler is shown. In particular, cross section A of intercooler  55  shown in  FIG. 4  is illustrated. Intercooler  55  includes fins  404  and coolant tubes  406 . The inlets and outlets of a plurality of coolant tubes  406  are combined at inlet manifold  502  and outlet manifold  504 . Inlet manifold  502  and outlet manifold  504  are in communication with coolant passages  304  of  FIG. 3 . 
         [0038]    Referring now to  FIG. 6 , a front view of an intake manifold is shown. In particular, an input manifold that directs air from a compressor integrated into an engine block to engine cylinders as illustrated in  FIG. 1  is shown. Air enters from the bottom  600  of intake manifold  58  and exits manifold sides at  602 . Intake manifold  58  is coupled to engine block  101  and intercooler  55  of  FIG. 1 . Intake manifold  58  directs compressed air from an intercooler (e.g. intercooler  55  of  FIGS. 1 ,  4 - 5 ) to engine cylinders for increasing the engine air amount. 
         [0039]    It should also be mentioned that the engine block of  FIGS. 1-3  may be part of a naturally aspirated engine where compressor scrolls and other compressor components are omitted from the compressor housing. Thus, a single block having an integrated compressor housing may be used for both supercharged and naturally aspirated engines. 
         [0040]    Referring now to  FIG. 7 , a plan view of a bottom of an intake manifold is shown. In particular, a bottom of the intake manifold shown in  FIGS. 1 and 6  is shown. Intake manifold  58  includes inlet  702  and outlets  706  and  708 . Air enters intake manifold  58  at air inlet  702  from an intercooler (e.g., the intercooler of  FIGS. 1 ,  4 - 5 ) and exits intake manifold  702  at outlets  706  and  708 . Intake manifold  58  also included bypass port  704  for bypassing air from an intake system to engine cylinders. For example, bypass port  704  can direct air from inlet passage  149  of  FIG. 1  to engine cylinders. Thus, port  704  can direct air from an inlet passage such that the air bypasses compressor  37  and intercooler  55  of  FIG. 1 . 
         [0041]    Thus, the present description provides for a system, comprising: an engine block having a plurality of cylinders for housing a plurality of pistons, said engine block contiguous with at least a portion of a supercharger air compressor housing, said supercharger air compressor housing having an inlet for fresh air and an outlet that provides compressed air to cylinders in said engine block; and a cylinder head receiving air from said supercharger air compressor housing. The system where said engine cylinder block includes at least one boss for coupling a compressor scroll or rotor to said engine cylinder block and where said cylinder head is at least one cylinder head coupled to said engine block. The system further comprising an intercooler coupled to said engine cylinder block, said intercooler located above said compressor scroll or rotor. The system where said engine cylinder block is a V type engine block. The system where said at least a portion of said compressor housing is located in between cylinder in the valley of the V engine. The system where said supercharger air compressor housing includes a front cover coupled to said engine block, said front cover positioned in a vertical orientation with respect to a position of said engine block in a vehicle. 
         [0042]    The present description also provides for a system, comprising: an engine cylinder block having a plurality of cylinders for housing a plurality of pistons, said engine cylinder block contiguous with at least a portion of a supercharger air compressor housing, said air compressor housing including at least one at least partially machined surface for accommodating a compressor rotor or scroll; and at least one cylinder head coupled to said engine cylinder block. The system where said at least one at least partially machined surface is inside said compressor housing and where said at least one compressor rotor or scroll is driven by a crankshaft, said crankshaft coupled to said engine cylinder block. The system further comprising a port for inducting gases from a crankcase to said air compressor housing, said crankcase at least partially formed by said engine block, and an oil separator positioned along said port. The system further comprising a front cover coupled to said engine block, said front cover positioned in a vertical orientation with respect to a mounting position of said engine block in a vehicle. The system further comprising an intercooler coupled to said engine cylinder block, said intercooler located above said compressor scroll or rotor, said intercooler in communication with at least a coolant passage of said engine cylinder block or with a cylinder head coupled to said cylinder block. The system where said at least one at least partially machined surface is machined in referenced to a datum of said engine cylinder block. The system further including a manifold directing compressed air from said intercooler to said cylinder head. 
         [0043]    The present description further provides for a system, comprising: an engine cylinder block having a plurality of cylinders for housing a plurality of pistons, said engine cylinder block contiguous with at least a portion of a supercharger air compressor housing; an intake manifold in communication with said supercharger air compressor housing; and an intercooler positioned in an air path downstream of said supercharger air compressor housing and upstream of said intake manifold. The system of where said intercooler is coupled to said engine cylinder block and said intake manifold. The system where said engine cylinder block is a V type cylinder block. The system where said at intercooler is positioned in the valley of said V type cylinder block. The system where at least one compressor rotor or scroll is located within said supercharger compressor housing and where said at least one compressor rotor or scroll is driven by a crankshaft or a camshaft, said crankshaft coupled to said engine cylinder block said camshaft coupled to a cylinder head. The system where said intercooler is in communication with at least a coolant passage of said engine cylinder block. The system where said intake manifold includes a port for bypassing said supercharger air compressor housing and said intercooler. 
         [0044]    It should be appreciated that the engine configurations illustrated by  FIGS. 1-7  is exemplary in nature and that other configurations are anticipated by this description. For example, an air compressor may be integrated into the V section of an engine block where a portion of the compressor housing is coupled to the V section of the engine block such that a portion of the compressor housing is formed by the engine block and another portion of the compressor housing is formed by a separate piece of material. 
         [0045]    Referring now to  FIG. 8 , a flow chart for supplying air to cylinders of an engine having a compressor housing that is at least partially integrated into an engine block is shown. At  802 , routine inducts air to an area of an engine block for pressurization. In one example, fresh air is inducted into the valley of an engine of V type configuration where the compressor housing is a continuous part of the engine block. 
         [0046]    At  804 , routine  800  judges whether or not to direct fresh air around the compressor integrated into the cylinder block. Air may bypass the compressor by directing air from an air duct located upstream of the compressor to the intake manifold. Routine  800  judges whether or not to bypass the compressor in response to operating conditions of the engine. In one example, air can bypass the compressor when the position of a throttle is less than a predetermined amount or when engine load is less than a predetermined amount. Routine  800  proceeds to  806  when it is judged desirable to pressurize fresh air entering the engine. Otherwise, routine  800  proceeds to exit. 
         [0047]    At  806 , routine  800  judges whether or not to evacuate the crankcase of gases. Crankcase gases may include a mixture of air and hydrocarbons. Air may enter the engine crankcase when small amounts of cylinder charge pass the engine pistons and rings. Hydrocarbons in the engine crankcase may come from engine oil or from portions of cylinder charge that pass engine pistons. In one example, gases from the crankcase are routed from the crankcase to the compressor when engine load exceeds a predetermined threshold load amount. Since the compressor is a contiguous portion of the engine block, crankcase gases can be evacuated without the gases exiting the engine block. Routine  800  proceeds to  808  if it is judged not to evacuate gases from the engine crankcase. Routine  800  proceeds to  816  if it is judged to evacuate gases from the engine crankcase. 
         [0048]    At  816 , routine pulls gases from the engine crankcase. In one example, a crankcase ventilation valve is opened so that gases pass through a wall of an engine block that separates the engine crankcase and the compressor low pressure chamber. Further, in one example, the compressor low pressure chamber is part of a contiguous engine block. Routine  800  proceeds to  808  after the evacuation of crankcase gases begins. 
         [0049]    At  808 , routine  800  compresses air from within the engine block. In one example, air contained in a valley area of a V type engine is compressed by a compressor having a housing that is at least partially part of a continuous engine block. The compressor includes scrolls or lobes for pressurizing air that enters the engine block. Routine  800  proceeds to  810  after pressurizing air from the engine block. 
         [0050]    At  810 , routine routes compressed air through an intercooler. In one example, the intercooler may be coupled to the sides of an engine block and above a compressor, the compressor located in the valley of the engine. Routine  800  proceeds to  812  after fresh air is routed to the intercooler. 
         [0051]    At  812 , routine  800  cools compressed air with engine coolant from the engine block. In one example, coolant is passed directly from the engine block to the intercooler without any intermediate hoses or connections by coupling the intercooler to the engine block and aligning engine block coolant ports with coolant ports located on the intercooler. Routine  800  proceeds to  814  after compressed air is cooled with engine coolant. 
         [0052]    At  814 , engine cylinders are supplied with cooled compressed air. In one example, an intake manifold routes air from an intercooler to engine cylinders. In particular, an outlet port of an intercooler is mated to an inlet port of an intake manifold, and the intake manifold outlet ports are mated to intake ports of a cylinder head. In this way, cooled compressed air is routed from an intercooler to engine cylinders. Additionally, the intake manifold may be in the same plane as the cylinder head air inlets so that the intake runners of the intake manifold are horizontal. Routine  800  proceeds to exit. 
         [0053]    As will be appreciated by one of ordinary skill in the art, routines described in  FIG. 8  may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various steps or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the objects, features, and advantages described herein, but is provided for ease of illustration and description. Although not explicitly illustrated, one of ordinary skill in the art will recognize that one or more of the illustrated steps or functions may be repeatedly performed depending on the particular strategy being used. 
         [0054]    This concludes the description. The reading of it by those skilled in the art would bring to mind many alterations and modifications without departing from the spirit and the scope of the description. For example, I3, I4, I5, V6, V8, V10, and V12 engines operating in natural gas, gasoline, diesel, or alternative fuel configurations could use the present description to advantage.