Abstract:
A direct fuel injector is positioned to provide better fuel atomization within the combustion chamber. The direct fuel injector is disposed between an intake manifold and a cylinder head assembly thereby eliminating the need for additional fuel delivery conduits, thus decreasing the size of the engine and lowering the production costs of the outboard motor. The direct fuel injector position permits immediate air/fuel mixture adjustments allowing improved acceleration enrichment and lean stratified charge operation. The direct fuel injector position and routing of induction system components allows for compact placement of auxiliary components. The integrated direct fuel injector position enables the operator to enjoy compact engine design, improved engine performance and increased fuel efficiency.

Description:
PRIORITY INFORMATION  
         [0001]    This application is based on and claims priority to Japanese Patent Application No. 2001-327636, filed Oct. 25, 2001, the entire contents of which is hereby expressly incorporated by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates generally to an engine fuel delivery system for an engine, and more particularly to an improved fuel injector and cylinder head assembly allowing for a more compact engine design and stratified-charge operation.  
           [0004]    2. Brief Description of Related Art  
           [0005]    One important characteristic of an engine is its output power. A great deal of engineering is involved with improving the output power of an engine. In addition, an equal amount of care is often involved with maintaining the output power when developing and installing additional engine systems and components.  
           [0006]    One particularly sensitive system is the air induction system. Typically, induction systems for engines designed for outboard motor use include a plenum chamber, a throttle body, and an intake passage. In addition, typical engines include a fuel delivery system which cooperates with the air induction system to deliver an air/fuel charge to a combustion chamber of the engine. The fuel delivery system typically comprises a fuel tank, one or more fuel conduits, and a fuel injector for those engines using a direct injection method of delivering fuel to a combustion chamber. The fuel delivery system commonly includes fuel injectors mounted in close proximity to an engine body to inject fuel directly into a cylinder head or into an intake passage that communicates with the combustion chamber.  
           [0007]    These two cooperating systems must be configured to deliver air and fuel to the combustion chamber. However, these systems must be carefully engineered so as to reduce the flow resistance in each of these systems, which can have an adverse effect on the engine efficiency, and hence, the output power.  
           [0008]    Perhaps the greater importance is the configuration of the air induction system and, particularly, the routing of the air intake pipes, intake manifold, and intake runners. It is preferable that the air intake pipes have a low flow resistance, and hence it becomes undesirable for the intake pipes to be bent or tapered to avoid interference with other engine accessories, which can increase the intake resistance, and therefore, result in the reduction of engine output power.  
           [0009]    Many of the engine accessories can be beneficially located to provide for a smoother operating and more efficient engine. Unfortunately, the desired location of these accessories can interfere with the preferred routing of the induction system components. While the engine accessories can be mounted in various locations around the engine, their location must be balanced against the desire to maintain a compact engine.  
           [0010]    Due to compact engine design demands, fuel injectors are often placed close to the outside of the engine body. However, heat transfer issues can arise when the fuel injectors are placed in proximity to the engine body, and heat generated within the engine body from the combustion process flows to the fuel injectors and heats the fuel before it is injected into the combustion chamber, which can reduce the engine efficiency.  
         SUMMARY OF THE INVENTION  
         [0011]    One aspect of the present invention includes the realization that the induction system components can be beneficially configured and routed to provide a low flow resistance while allowing for a sufficient space to mount auxiliary components in close proximity to the engine body thus providing a compact engine arrangement. An additional aspect includes the realization that the fuel injectors can be located in close proximity to the engine body and the heat transfer reduced by indirect cooling from the adjacent air induction system components.  
           [0012]    In accordance with another aspect of the invention, a four-cycle engine for use in an outboard motor comprises a cylinder body defining at least one cylinder bore therethrough, a cylinder head assembly connected to the cylinder body, and a piston disposed within the cylinder bore. The cylinder body, the cylinder head assembly, and the piston cooperate to define a combustion chamber.  
           [0013]    At least one intake passage is formed in the cylinder head assembly. A crankshaft is rotatably coupled to the piston. Additionally, a fuel injector has a longitudinal axis and is arranged to directly inject fuel into the combustion chamber. The fuel injector is additionally disposed between the intake passage and an imaginary line extending laterally from a junction between the cylinder body and the cylinder head assembly when viewed from a direction along an axis of the crankshaft. In this orientation, the fuel injector axis is arranged to be substantially parallel to the intake passage defined by the cylinder head assembly.  
           [0014]    An induction system is connected to the intake passage and extends generally laterally from the cylinder head assembly and then along a side of the cylinder body at a distance from the cylinder body. An auxiliary component is disposed in a space formed between the induction system and the cylinder body.  
           [0015]    The cylinder head assembly can include at least two intake passages that are disposed next to each other in a direction that extends generally parallel to the axis of the crankshaft, and the fuel injector can be disposed in a vicinity between the two intake passages.  
           [0016]    The auxiliary component disposed in the space formed between the cylinder body and the induction system can be a fuel vapor separator, a throttle link mechanism, a battery, a starter motor, an oil filter, or a fuel cooler or any combination thereof, including additional auxiliary components not specifically listed.  
           [0017]    According to one embodiment in which the cylinder body defines a plurality of cylinder bores arranged in a V-shape, the induction system is disposed on the exterior of the V-shape.  
           [0018]    According to another aspect, a four-cycle engine comprises an engine block defining a cylinder bore and has a cylinder head assembly attached to the cylinder block to close one end of the cylinder bore. The cylinder head assembly includes at least one intake passage. A piston is positioned within the cylinder bore and is arranged to reciprocate along a cylinder axis so as to define a variable volume combustion chamber together with the cylinder bore and the cylinder head. The intake passage of the cylinder head communicates with the combustion chamber through at least one intake port. A fuel injector is configured to inject fuel directly into the combustion chamber and is disposed between the engine body and the intake passage. The fuel injector preferably has a longitudinal axis that is oblique to the cylinder axis.  
           [0019]    The fuel injector can be positioned between the intake passage and a plane extending laterally from a junction of the engine body and the cylinder head assembly. The fuel injector longitudinal axis can be arranged generally parallel to a flow axis of the intake passage.  
           [0020]    According to yet another aspect, an engine having an engine body comprises at least one variable volume combustion chamber defined in part by a head of a moveable piston. At least one intake port opens into the combustion chamber. An induction system communicates with the intake port through at least intake passage formed in a cylinder head of the engine body. An intake valve is moveable to regulate communication between the induction system and the combustion chamber through the intake port and the intake passage. The fuel delivery system has at least one fuel injector arranged to lie generally parallel to the intake passage for injecting fuel into the combustion chamber. The fuel injector is preferably positioned between the engine body and the intake passage. The fuel injector can be oriented such that the fuel injector injects fuel into the combustion chamber toward the head of the piston.  
           [0021]    The engine body can comprise a crankcase, a cylinder block, and a cylinder head assembly. In this embodiment, the induction system can extend away from the cylinder head assembly, along a side of the cylinder block, and toward the crankcase.  
           [0022]    According to another aspect, an outboard motor comprises an engine including an engine body, the engine body cooperating with at least one reciprocating piston to define at least one combustion chamber. An induction system is configured to guide air to the combustion chamber through at least a pair of intake ports. At least one fuel injector is configured to inject fuel for combustion in the combustion chamber. The fuel injector is preferably mounted between the engine body and at least a portion of the induction system and is generally in between the pair of intake ports. The fuel injector is configured to spray fuel toward the piston.  
           [0023]    The engine body can comprise a cylinder body connected to a cylinder head, and wherein the fuel injector is located between the induction system and a plane extending laterally from the connection between the cylinder body and the cylinder head. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]    The foregoing features, aspects, and advantages of the present invention will now be described with reference to the drawings of preferred embodiments that are intended to illustrate and not to limit the invention. The drawings comprise six figures in which:  
         [0025]    [0025]FIG. 1 is a partial top plan view of an outboard motor configured in accordance with a preferred embodiment of the present invention, with a portion of an engine of the outboard motor shown in section;  
         [0026]    [0026]FIG. 2 is a side elevational view of the engine of FIG. 1, showing portions of the induction and fuel injection systems;  
         [0027]    [0027]FIG. 3 is a partial cutaway view of a cylinder head of the engine illustrating the intake passageways and portions of the fuel system;  
         [0028]    [0028]FIG. 4 is a sectioned view of the cylinder head taken along line IV-IV of FIG. 3;  
         [0029]    [0029]FIG. 5 is a sectioned view of the cylinder head taken along line V-V of FIG. 3; and  
         [0030]    [0030]FIG. 6 is a partial top plan view of an outboard motor configured in accordance with another preferred embodiment of the present invention, with a portion of an engine of the outboard motor shown in section. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0031]    With reference to FIGS. 1 and 2, an overall construction of an outboard motor  30  that employs an internal combustion engine  32  configured in accordance with certain features, aspects and advantages of the present invention is described below. The engine  32  has particular utility in the context of a marine drive, such as the outboard motor, and thus is described in the context of an outboard motor. The engine  32 , however, can be used with other types of marine drives (i.e., inboard motors, inboard/outboard motors, jet drives, etc.) and also certain land vehicles. In any of these applications, the engine  32  can be oriented vertically or horizontally. Furthermore, the engine  32  can be used as a stationary engine for some applications that will become apparent to those of ordinary skill in the art.  
         [0032]    As used through this description, the terms “forward,” “forwardly”, “front”, and the abbreviation “Fw” mean at or to the side where the outboard motor is attached to a boat, and the terms “rear,” “reverse,” “backwardly” and “rearwardly” mean at or to the opposite side of the front side, unless indicated otherwise or otherwise readily apparent from the context in which these terms are used.  
         [0033]    The illustrated outboard motor  30  comprises a protective cowling assembly  34  containing the internal combustion engine  32 . As is known in the art, the cowling assembly  34  is generally part of a power head (not shown), which is connected to a housing unit (not shown). The power head is disposed atop the housing unit and includes the internal combustion engine  32  and the protective cowling assembly  34 .  
         [0034]    Preferably, the protective cowling assembly  34 , which preferably is made of a light-weight material, for example, plastic or fiberglass, defines a generally closed cavity  36  in which the engine  32  is disposed. As is known in the art, the protective cowling assembly generally comprises an upper cowling member (not shown) that is removably attached to a lower cowling member (not shown). The cowling  34  has one or more openings therein to allow the cavity  36  to communicate with the atmosphere. Accordingly, atmospheric air is drawn into the cavity  36 , and eventually, into the induction system  60 .  
         [0035]    The engine  32  in the illustrated embodiment operates on a four-cycle combustion principle. The engine  32  has a cylinder block  38 , which in the illustrated embodiment, defines four in-line cylinder bores  40  that extend generally horizontally and that are generally vertically spaced from one another.  
         [0036]    This type of engine, however, merely exemplifies one type of engine on which various aspects and features of the present invention can be suitably used. Engines having other numbers of cylinders, having other cylinder arrangements (V, W, opposing, etc.), and operating on other combustion principles (e.g., crankcase compression two-stroke, diesel, or rotary) also can employ various features, aspects and advantages of the present invention. In addition, the engine can be formed with separate cylinder bodies rather than a number of cylinder bores formed in a cylinder block  38 . Regardless of the particular construction, the engine preferably comprises an engine body that includes at least one cylinder bore.  
         [0037]    A moveable member, such as a reciprocating piston  42 , moves relative to the cylinder block  38  in a suitable manner. In the illustrated arrangement, the piston  42  reciprocates within each cylinder bore  40 , as is well-known.  
         [0038]    A cylinder head assembly  44  is affixed to one end of the cylinder block  38  to close one end of the cylinder bores  40 . The cylinder head assembly  44 , together with the associated pistons  42  and cylinder bores  40 , preferably defines four combustion chambers  46 . Of course, the number of combustion chambers can vary, as indicated above.  
         [0039]    A crankcase member  48  closes the other end of the cylinder bores  40  and, together with the cylinder block  38 , defines a crankcase chamber  50 . A crankshaft  52  extends generally vertically through the crankcase chamber  50  and can be journaled for rotation by several bearing blocks (not shown).  
         [0040]    Connecting rods  54  couple the crankshaft  52  with the respective pistons  42  in any suitable manner. Thus, the crankshaft  52  can rotate with the reciprocal movement of the pistons  42 .  
         [0041]    Preferably, the crankcase member  48  is located at the forward side of the engine  32 , with the cylinder block  38  and the cylinder head assembly  44  being disposed rearward from the crankcase member  48 . Generally, the cylinder block  38 , the cylinder head assembly  44  and the crankcase member  48  together define an engine body  56 .  
         [0042]    The engine  32  also comprises an air induction system  60 . The air induction system  60  guides air from within the cavity  36  to the combustion chambers  46 . The air induction system  60  preferably comprises a single plenum chamber in communication with the space  36  inside the cowling  34 . Preferably, the plenum chamber  66  acts as an intake silencer to attenuate noise generated by the flow of air into the respective combustion chambers  46 . The plenum chamber is coupled to four throttle bodies  72  by four intake pipes  63 . The throttle bodies  72  are in turn connected to an intake manifold  74  at a manifold flange  75  which provides a substantially air tight seal. The intake manifold  74  defines a plurality of intake runners  64  that are each coupled to a plurality of intake passages  62 , which each communicate with a combustion chamber through associated intake ports  73 .  
         [0043]    In the illustrated embodiment, each of the intake passages  62  extends between a single inlet opening on an outer surface of the cylinder head assembly  44  and a single intake port  73  which opens to the combustion chamber  46 . A single intake runner  64  is preferably bifurcated by a conduit separator  65  and thereby delivers air to a pair of intake passages  62  that deliver intake air to a single combustion chamber  46 .  
         [0044]    According to an alternative embodiment, an intake passage  62  may be bifurcated thereby allowing a single intake runner  64  to deliver air to a pair of intake ports  73 . Accordingly, a single intake runner  64  communicates with a single intake passage  62  which bifurcates and delivers intake air into the combustion chamber  46  through a pair of intake ports  73 .  
         [0045]    Intake valves  68  are slidably disposed at the intake ports  73  to move between an open and a closed position. The intake valves  68  are preferable in sealing engagement with a valve seat (not shown) carried by the intake port  73  to form a substantially air-tight seal. The intake valves  68  act to open and close the intake ports  73  to control the flow of air from the intake passages  62  into the combustion chamber  46 .  
         [0046]    Each illustrated throttle body  72  has a butterfly type throttle valve  78  journaled for pivotal movement about an axis defined by a generally vertically extending valve shaft  80 . Each valve shaft  80  can be coupled with the other valve shafts to allow simultaneous movement by a throttle valve coupler  81 . The valve shaft  80  is operable by the operator through an appropriate conventional throttle valve linkage and a throttle lever connected to the end of the linkage. The throttle valves  78  are movable between an open position and a closed position to meter or regulate an amount of air flowing through the induction system  60 . Normally, the greater the opening degree, the higher the rate of airflow and the higher the power output of the engine  32 .  
         [0047]    In order to bring the engine  32  to idle speed and to maintain this speed, the throttle valves  78  generally are substantially closed. Preferably, the valves are not fully closed which produces a more stable idle speed and inhibits sticking of the throttle valves  78  in the closed position. As used through the description, the term “idle speed” generally means a low engine speed that achieved when the throttle valves  78  are closed but also includes a state such that the valves  78  are slightly more open to allow a relatively small amount of air to flow through the intake runners  64 .  
         [0048]    The air induction system  60  preferably includes an auxiliary air device (AAD) (not shown) that bypasses the throttle valves  78  and extends from the plenum chamber  66  to the respective intake runners  64  downstream of the throttle valves  78 . Idle air can be delivered to the combustion chambers  46  through the AAD when the throttle valves  78  are placed in a substantially closed or closed position.  
         [0049]    The AAD preferably comprises an idle air passage, an idle valve and an idle valve actuator. The idle air passage is branched off to the respective intake runners  64 . The idle valve controls flow through the idle air passage such that the amount of air flow can be more precisely controlled. Preferably, the idle valve is a needle valve that can move between an open position and a closed position, which closes the idle air passage. The idle valve actuator actuates the idle valve to a certain position to meter or adjust an amount of the idle air, and thus more finely adjust the idle speed of the engine.  
         [0050]    As best shown in FIG. 1, the air induction system  60 , beginning with the plenum chamber  66  extends rearwardly generally along the cowling  34  until it extends beyond an imaginary plane  114  corresponding with the junction of the cylinder block  38  and the cylinder head assembly  44 . The intake passage manifold  74  then curves and extends toward the cylinder head assembly  44  and mates therewith as described in further detail below. The intake runners  64  are in communication with intake passages  62  formed within the cylinder head assembly  44 . This particular routing of the induction system  60  components creates a significant auxiliary space  79  which will be discussed later in detail.  
         [0051]    The engine  32  also comprises an exhaust system  71  that guides burnt charges, i.e., exhaust gases, to a location outside of the outboard motor  30 . Each cylinder bore  40  preferably has two exhaust ports  82  defined in the cylinder head assembly  44 . The exhaust ports  82  can be selectively opened and closed by exhaust valves  84 . The construction of each exhaust valve  84  and the arrangement of the exhaust valves are substantially the same as the intake valves  68  and the arrangement thereof, respectively.  
         [0052]    An exhaust manifold  86  preferably is disposed next to the exhaust ports  82  and extends generally vertically. The exhaust manifold  86  communicates with the combustion chambers  46  through the exhaust ports  82  to collect exhaust gases therefrom. When the exhaust ports  82  are opened, the combustion chambers  46  communicate with an exhaust passage (not shown) through the exhaust manifold  86  to discard the exhaust gasses.  
         [0053]    With continued reference to FIGS. 1 and 2, the engine  32  preferably includes a direct fuel injection system. The fuel injection system preferably comprises four fuel injectors  90  with one fuel injector  90  allotted for each of the respective combustion chambers  46 .  
         [0054]    The engine  32  further comprises an ignition or firing system. Each combustion chamber  46  is provided with a spark plug (not shown) that is connected to an electronic control unit (ECU) (not shown) through an igniter so that ignition timing is also controlled by the ECU. Each spark plug has electrodes that are exposed into the associated combustion chamber and are spaced apart from each other with a small gap. The spark plugs generate a spark between the electrodes to ignite an air/fuel charge in the combustion chamber  46  at selected ignition timing under control of the ECU.  
         [0055]    In the illustrated engine  32 , the pistons  42  reciprocate between top dead center and bottom dead center positions. When the crankshaft  52  makes two rotations, the pistons  42  generally move from the top dead center to the bottom dead center (the intake stroke), from the bottom dead center to the top dead center (the compression stroke), from the top dead center to the bottom dead center (the power stroke) and from the bottom dead center to the top dead center (the exhaust stroke). During the four strokes of the pistons  42 , an actuation device  89  triggers an intake camshaft  91  to make one rotation which actuates the intake valves  68  and an exhaust camshaft  93  to make one rotation which actuates the exhaust valves  84  to open the intake passages  62  during the intake stroke and to open exhaust ports  82  during the exhaust stroke, respectively. The camshafts  91 ,  93  are generally protected by a cam cover  95  that is connected to the cylinder head assembly  44  in any suitable manner.  
         [0056]    Generally, during the intake stroke, air is drawn into the combustion chambers  46  through the air intake passages  62  and fuel is injected into the combustion chambers  46  by the fuel injectors  90 . The fuel can alternatively or additionally be injected by the fuel injectors  90  into the intake runners  64  or intake passages  62 . The air and the fuel thus are mixed to form the air/fuel charge in the combustion chambers  46 . Slightly before or during the power stroke, the respective spark plugs ignite the compressed air/fuel charge in the respective combustion chambers  46 . The air/fuel charge rapidly burns during the power stroke to move the pistons  42  toward their bottom dead center positions. The burnt charge, i.e., exhaust gases, then are discharged from the combustion chambers  46  during the exhaust stroke.  
         [0057]    During engine operation, heat builds in the engine body  56 . The illustrated engine  32  thus includes a cooling system to cool the engine body  56 . The outboard motor preferably employs an open-loop type water cooling system that introduces cooling water from the body of water surrounding the motor  30  and then discharges the cooling water to a surrounding body of water. The cooling system includes one or more water jackets defined within the engine body  56  through which the water travels to remove heat from the engine body  56 . Further description of this system is not required to gain an understanding of the inventions described herein, and thus, will be omitted.  
         [0058]    The engine  32  also preferably includes a lubrication system. A closed-loop type system is employed in the illustrated embodiment. The lubrication system comprises a lubricant tank defining a reservoir (not shown), and an oil pump (not shown), which is provided at a desired location, to pressurize the lubricant oil in the reservoir and to pass the lubricant oil through a suction pipe toward certain engine portions, which desirably are lubricated, through lubricant delivery passages. Such engine portions include, for example, the crankshaft bearings (not shown), the connecting rods  54  and the pistons  42 . Lubricant return passages (not shown) also are provided to return the oil to the lubricant tank for re-circulation. The lubrication system may be any type that is well known in the art, and will not be discussed further.  
         [0059]    As previously noted, the engine  32  includes a fuel delivery system  92  which preferably comprises a fuel tank (not shown), a fuel pump (not shown), a vapor separator assembly  94  (FIG. 1), a fuel rail  97 , a fuel delivery pipe  96 , and a fuel injector  90 . The fuel tank may be placed in any desired position about the outboard motor, or remotely within the boat to which the outboard motor is attached. A fuel pump is operatively connected to the fuel tank and additionally to a vapor separator assembly  94 . A fuel rail  97  is in fluid communication with the vapor separator assembly  94  and carries a fuel delivery pipe  96  which, in turn, is connected to one or more fuel injectors  90 . In the illustrated embodiment, the fuel delivery pipe  96  is placed in close proximity to the intake manifold  74 . In this position, the fuel delivery system can be more compact, thereby allowing for the placement of various necessary fuel delivery system components. A fuel pressure regulator (not shown), an additional fuel cooler (not shown), a fuel pressurizer (not shown) in addition to alternative components can all be mounted directly onto or in the close vicinity of the fuel delivery system  92 .  
         [0060]    Moreover, the fuel delivery pipe  96  is preferably positioned in close proximity to the intake manifold  74  and intake passages  62 . Mounting the various fuel delivery system  92  components in the close vicinity of the intake manifold  74  and intake passages  62  allows for a compact design that requires less complicated production thereby providing a cost savings. A further benefit of this fuel delivery system  92  arrangement is that induction air traveling through the air induction system  60  cools the surrounding intake manifold  74 , which in turn, cools the fuel flowing through the fuel delivery pipes  96 . The cooled fuel, when mixed with the induction air within the combustion chamber  46 , provides a cooler, more dense air/fuel mixture permitting the engine to operate more efficiently.  
         [0061]    The fuel injector  90  is advantageously mounted in a position between the cylinder head assembly  44  and the intake manifold  74 , thereby allowing for a more compact arrangement. Additionally, the fuel can be delivered directly to the fuel injector  90  from the fuel delivery pipe  96  omitting unnecessary additional fuel conduits. As illustrated, the fuel injector  90  can be positioned substantially parallel to the intake passages  62  which orients the fuel injector&#39;s longitudinal axis oblique to an axis of the cylinder. Positioning the fuel injector  90  in such a position allows for efficient use of space between the intake manifold  74  and the cylinder block  38 , allowing a greater auxiliary space  79  for additional components, such as, for example, a fuel vapor separator  94 , a throttle link mechanism (not shown), a battery (not shown), a starter motor (not shown), an oil filter (not shown), a fuel cooler (not shown), a pressure regulator (not shown), a fuel pressurizer (not shown) or other auxiliary components.  
         [0062]    With additional reference to FIGS.  3 - 5 , the intake port  62  and/or intake runner  64  can incorporate a conduit separator  65  thereby bifurcating the intake runner  64  and/or intake port  62 , as previously described. Preferably, the conduit separator  65  is located within the intake runner  64 , thus allowing a single intake runner  64  to incorporate dual air outlets, and thus deliver intake air to a pair of intake passages  62  formed within the cylinder head assembly  44 . The intake manifold  74  is preferably connected to the cylinder head assembly  44 , such as by bolts. Accordingly, the intake manifold  74  terminates in a mounting seat  99  and has one or more bolt holes  101  formed therein for attachment to the cylinder head assembly  44 .  
         [0063]    The cylinder head assembly  44  preferably has additional bolt holes  101  for accommodating mounting bolts  103  to connect the fuel rail  97  with concomitant fuel delivery pipe  96  to the cylinder head assembly  44 . The fuel rail  97  includes a plurality of bosses  105 , preferably one for each fuel injector  90 . The fuel injectors  90  are mounted to the bosses  105  in any suitable manner and are in communication with the fuel delivery pipe  96 .  
         [0064]    With particular reference to FIG. 5, a fuel delivery side  100  of the fuel injector  90  is positioned within a fuel injector inlet recess  102 . Preferably, an o-ring  104  is disposed between the delivery side of the fuel injector and the fuel injector inlet  106  to provide an enhanced seal between the fuel injector  90  and the fuel delivery pipe  96 .  
         [0065]    A fuel injector nozzle (not shown) is advantageously positioned within a cylinder head assembly  44  allowing proper positioning of the fuel injector  90  with reference to the combustion chamber  46 . The orientation of the fuel injector  90  with reference to the combustion chamber  46  improves control of the fuel injection in delivering a desired air/fuel mixture.  
         [0066]    For example, but without limitation, when the throttle valve  78  is suddenly opened, such as when pulling a water skier from the water, induction air is quickly accelerated and initially generates a lean mixture in the combustion chamber  46 . Such a lean mixture can lead to unwanted misfiring of the engine  32 . The position of the fuel injector  90  provides atomization of the air/fuel mixture directly in the combustion chamber, allowing a fast reacting fuel enrichment during sudden acceleration. The fast acting fuel enrichment provides a richer mixture which reduces misfiring and thus provides smoother acceleration.  
         [0067]    In one embodiment, a bracket assembly  110  advantageously holds the fuel injector  90  in its mounted position between the intake manifold  74  and the cylinder head assembly  44 . The bracket assembly  110  includes a bolt or fastener  112  to securely position the fuel injector  90  such that the fuel injector  90  is unable to rotate. In the illustrated embodiment, the fuel injector  90  is mounted such that its longitudinal axis is approximately parallel to the longitudinal axis of the intake port  62 . The fuel injector  90  can include a spray nozzle (not shown) which can be oriented independently of the fuel injector  90  longitudinal axis. However, it is preferable that the fuel spray from the spray nozzle is directed toward the piston  42  within the cylinder bore  40 , as best illustrated in FIG. 1.  
         [0068]    As shown in FIGS. 1 and 3, the fuel injector  90  is disposed substantially between the intake ports  62  and a plane defined by the junction of the cylinder head assembly  44  and the cylinder block  38 . As such, the fuel injector  90  is compactly arranged within the cavity  79  formed between the engine body  38  and the air induction system  60 . Moreover, it is preferable to dispose the fuel injector  90  substantially between dual intake passages  62 . This results in a very compact arrangement of the fuel delivery system thus allowing for the outboard motor  30  to be more compact. Additionally, by more efficiently orienting and positioning the fuel delivery components, there is an increased space  79  to allow for other components.  
         [0069]    As illustrated in FIGS. 1 and 2, the portion of the induction system  60  defined by the intake manifold  74  extends away from the cylinder head assembly  44 . The intake runners  64  extend from the outer end of the intake manifold  74  and curve forwardly, thus leaving an auxiliary space  79  between the induction system  60  and the engine body  38 . Thus, the auxiliary space  79  can be used for mounting other components, for example, but without limitation, the fuel pump, vapor separator assembly, throttle link mechanism, battery, starter motor, oil filter, fuel cooler, fuel pressurizer, pressure regulator, or other desired accessories. Moreover, because the space is used more efficiently than in prior art engines, the accessories are able to be added to the engine without substantially impacting the overall size of the outboard motor.  
         [0070]    The extent to which the portion of the intake passage extends away from the cylinder head assembly  44  affects the lateral dimension of the auxiliary space  79 . Thus, by shaping the intake runner  64  and the intake manifold  74  to extend around the fuel injector  90 , the auxiliary space  79  is enlarged sufficiently to accommodate additional components, thus allowing a compact arrangement within the auxiliary space  79 . Additionally, because the intake runners  64  extend around two sides of the fuel injector  90 , the heating effect of the engine body  56  on the fuel injectors  90  is at least partially compensated for by the cooling effect of the intake runner  64 .  
         [0071]    With reference to FIG. 6, an alternative embodiment of the four cycle engine  118  of the present invention is illustrated. In this illustrated embodiment, a plurality of cylinders are arranged in a V-shape configuration. A cylinder body  38  defines a plurality of cylinder bores  40 . Each cylinder bore  40  has a reciprocating piston  42  slidably disposed therein, which is coupled to a crankshaft  52  by connecting rods  54  as known in the art. A first cylinder bank  120  and second cylinder bank  122  each may comprise one, two, three or more cylinders and are angularly spaced from one another about the crankshaft. In the illustrated embodiment, the number and orientation of the cylinders results in a V-6 four-stroke engine. The engine operates in accordance with the principles discussed in relation to the inline four cylinder engine discussed above, and therefore, the above description of the engine and its systems applies equally to this embodiment and, consequently, common reference numerals are used to describe the V-6 engine of FIG. 6.  
         [0072]    One notable difference of the embodiments utilizing a V-6 engine is the necessity of dual induction systems  60   a,    60   b  and dual exhaust systems  71   a,    71   b  to service the twin cylinder banks  120 ,  122 . The aforementioned advantageous location and orientation of the fuel injectors  90  in combination with the spatial orientation of the induction systems  60   a,    60   b  provides equally advantageous benefits when used in the context of an engine having a V-shape cylinder bank configuration.  
         [0073]    Specifically, each induction system  60   a,    60   b  is spaced away from the engine body  56 , which results in an auxiliary space  79   a,    79   b  therebetween. In accordance with one aspect of the present invention, the induction systems  60   a,    60   b  begin with a plenum chamber  66 , which exits to a plurality of intake pipes  63 . The intake pipes  63  are coupled to throttle bodies  72 , which house a plurality of throttle valves  78 , as is known in the art. The throttle bodies  72  lead to an intake manifold  74  and are connected thereto at a manifold flange  75 . The intake manifold  74 , as described, defines a number of intake runners  64  which are each bifurcated by a conduit separator  65  thereby providing a pair of outlets associated with each intake runner  64 . Accordingly, the cylinder head assembly  44  defines a pair of intake passages  62  that communicate with each pair of intake runner  64  outlets.  
         [0074]    As discussed above, the intake passages  62  are in selective communication with the associated combustion chamber  46  by intake valves  68 . Additionally, a fuel injector  90  is in communication with each combustion chamber  46 . It is the cooperation of the induction system  60  and the fuel injection system  92  that provides the necessary air/fuel charge to the combustion chamber  46 .  
         [0075]    It is desirable for the air induction system  60  to be configured with a low flow resistance to allow a greater volume of air to flow therethrough and to the combustion chamber  46 . A greater volume of air and fuel into the combustion chamber results in a more violent combustion process, and hence, increases engine output.  
         [0076]    Accordingly, the induction system  60  is preferably spaced away from the engine body  56  and generally follows the cowling  34 . This spacing of the induction system  60  from the engine body has the additional advantage of reducing heat transfer from the engine body  56  through the induction system  60  and to the intake air.  
         [0077]    Preferably, the induction system  60  extends generally linearly from the plenum chamber  66  to a location that is beyond an imaginary line  114  extending laterally from the connection between the cylinder body  38  and the cylinder head assembly  44 . The induction system  60  then curves and extends toward the cylinder head assembly  44  and mates therewith. Preferably, the curvature of the induction system is smooth and has a fairly large radius to minimize any efficiency losses due to the increase in friction caused by the curvature of the induction system  60 .  
         [0078]    Portions of the fuel delivery system  92  are disposed generally adjacent to the induction system, and more specifically, adjacent to the intake manifold  74 . More preferably, the fuel rail  97 , fuel delivery pipe  96 , and fuel injectors  90  are disposed between the imaginary line  114  and the intake manifold  74 .  
         [0079]    By arranging the fuel delivery system  92  components in a compact position, a greater auxiliary space  79   a,    79   b  is provided to house additional auxiliary components, such as a vapor fuel separator  94 , a throttle link mechanism  126 , an oil filter (not shown), a fuel cooler (not shown), a fuel pressurizer (not shown), a pressure regulator (not shown) and other additional components. In at least one embodiment, the fuel vapor separator  94  is able to have an increased volume, thereby operating more efficiently to beneficially affect the engine performance. Additionally or alternatively, another auxiliary component, such as a throttle linkage  126 , may be placed in one or both of the auxiliary spaces  79   a,    79   b,  which advantageously keeps the linkage components short, thereby reducing any slop in the mechanism that is often introduced when the linkages must travel long distances to actuate the respective components.  
         [0080]    Moreover, by compacting the fuel delivery system  92  components adjacent to the induction system  60  components, the intake air indirectly cools the fuel through conduction between the fuel, fuel delivery system  92  components, induction system  60  components, and the intake air. The cooled fuel allows the engine to operate more efficiently by providing a more dense air/fuel charge.  
         [0081]    Finally, by creating and utilizing the increased auxiliary space  79   a,    79   b,  the auxiliary components can be fitted close to the engine body  56  which allows for a compact engine arrangement.  
         [0082]    Although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In addition, while a number of variations of the invention have been shown and described in detail, other modifications, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or subcombinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed invention. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims that follow.