Abstract:
An electronically controlled engine management system for an outboard motor, which determines the temperature of the engine and manipulates the engine management parameters to allow the engine to operate smoothly and efficiently. The engine temperature detection permits an efficient starting environment as well as an smooth starting to normal running transition period.

Description:
PRIORITY INFORMATION  
       [0001]    This application is based on and claims priority to Japanese Patent Application No. 2001-136545, filed May 7, 2001 and to the Provisional Application No. 60/322191, filed Sep. 13, 2001, (Attorney Docket No. FS.20015US0PR) the entire contents of which is hereby expressly incorporated by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates generally to an engine control system for an outboard motor, and more particularly to an improved engine management systems for better controlling both warm and cold starting and running conditions.  
         DESCRIPTION OF THE RELATED ART  
         [0003]    Watercraft engines typically incorporate an engine management system. Watercraft engines are started and operate in warm and cold environments and are expected to perform well in all conditions. Under such various environments the mixture to be combusted within the engine may be effected, for example when starting the engine while it is warm.  
           [0004]    When an engine is shut off after running at its correct operating temperature and then started again, it is characterized as a hot start. During such hot starts the mixture tends to be rich because the fuel vapors tend to accumulate and are delivered to the engine induction system upon starting. A warm starting engine may start and perform poorly due to this rich mixture. Along with poor running conditions an unnecessary increase in fuel consumption is caused when the mixture is too rich.  
           [0005]    Engines are often started in cold environments where a richer mixture is needed to compensate for the losses resulting from condensation on the cylinder walls and in order to facilitate starting the cold engine. Without this richer mixture the engine may start and perform poorly.  
         SUMMARY OF THE INVENTION  
         [0006]    One aspect of the present invention is to accurately monitor engine parameters and adjust various components to allow the engine to start and run correctly in all environments. Various components that can be adjusted in order to enhance engine starting and running performance may include the fuel injection, ignition, and allowing additional air to bypass the throttle valve.  
           [0007]    Constant monitoring of various engine parameters is performed to control engine-running variables to allow the engine to start and run correctly and efficiently under all temperature conditions. The engine control system monitors the engine temperature and the mixture is adjusted for all engine operational environments in order to provide the operator with a correct running engine. Such an advanced engine control system allows for a high performing engine life. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    The foregoing features, aspects, and advantages of the present invention will now be described with reference to the drawings of a preferred embodiment that is intended to illustrate and not to limit the invention. The drawings comprise seven figures in which:  
         [0009]    [0009]FIG. 1 is a side elevational view of an outboard motor configured in accordance with a preferred embodiment of the present invention, with an associated watercraft partially shown in section;  
         [0010]    [0010]FIG. 2 is a side elevational view of an upper section of an outboard motor configured in accordance with a preferred embodiment of the present invention, with various parts shown in phantom;  
         [0011]    [0011]FIG. 3 is a top view of an outboard motor configured in accordance with a preferred embodiment of the present invention, with various parts shown in phantom;  
         [0012]    [0012]FIG. 4 is a schematic diagram of the electronic control unit and its control parameters;  
         [0013]    [0013]FIG. 5 is a top view of an outboard motor configured in accordance with a preferred embodiment of the present invention, with various electronically controlled parameters shown;  
         [0014]    [0014]FIG. 6 is a graphical view showing engine parameters with reference to time;  
         [0015]    [0015]FIG. 7 is a flowchart representing a control routine arranged and configured in accordance with certain features, aspects, and advantages of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
     The Overall Construction  
       [0016]    With reference to FIGS.  1 - 5 , an outboard motor  10  includes a drive unit  12  and a bracket assembly  14 . The bracket assembly  14  attaches the drive unit  12  to a transom  16  of an associated watercraft  18  and supports a marine propulsion device such as propeller  57  in a submerged position relative to a surface of a body of water.  
         [0017]    As used to this description, the terms “forward,” “forwardly,” and “front” mean at or to the side where the bracket assembly  14  is located, unless indicated otherwise or otherwise readily apparent from the context use. The terms “rear,” “reverse,” “backwardly,” and “rearwardly” mean at or to the opposite side of the front side.  
         [0018]    The illustrated drive unit  12  includes a power head  20  and the housing unit  22 . Unit  22  includes a drive shaft housing  24  and the lower unit  26 . The power head  20  is disposed atop the housing unit  22  and includes an internal combustion engine  28  within a protective cowling assembly  30 , which advantageously is made of plastic. The protective cowling assembly  30  typically defines a generally closed cavity  32  in which the engine  28  is disposed. The engine  28  is thereby is generally protected by the cowling assembly  30  from environmental elements.  
         [0019]    The protective cowling assembly  30  includes a top cowling member  34  and a bottom cowling member  36 . The top cowling member  34  is advantageously detachably affixed to the bottom cowling member  36  by a suitable coupling mechanism to facilitate access to the engine and other related components.  
         [0020]    The top cowling member  34  includes a rear intake opening (not shown) defined from an upper end portion. This rear intake member with one or more air ducts can, for example, be formed with, or affixed to, the top cowling member  34 . The rear intake member, together with the upper rear portion of the top cowling member  34 , generally defines a rear air intake space. Ambient air is drawn into the closed cavity  32  near the rear intake opening and the air ducts of the rear intake member. Typically, the top cowling member  34  tapers in girth toward its top surface, which is in the general proximity of the air intake opening. This taper reduces the lateral dimension of the outboard motor, which helps to reduce the air drag on the watercraft  18  during movement.  
         [0021]    The bottom cowling member  36  has an opening for which an upper portion of an exhaust guide member  38  extends. The exhaust guide member  38  advantageously is made of aluminum alloy and is affixed to the top of the driveshaft housing  24 . The bottom cowling member  36  and the exhaust guide member  38  together generally form a tray. The engine  28  is placed on to this tray and can be connected to the exhaust guide member  38 . The exhaust guide member  38  also defines an exhaust discharge passage through which burnt charges (e.g., exhaust gases) from the engine  28  pass.  
         [0022]    The engine  28  in the illustrated embodiment preferably operates on a four-cycle combustion principle. With reference now to FIGS. 2 and 3, the engine embodiment illustrated is a DOHC six-cylinder engine having a V-shaped cylinder block  40 . The cylinder block  40  thus defines two cylinder banks, which extend generally side by side with each other. In the illustrated arrangement, each cylinder bank has three cylinder bores such that the cylinder block  40  has six cylinder bores in total. The cylinder bores of each bank extend generally horizontally and are generally vertically spaced from one another. This type of engine, however, merely exemplifies one type of engine. Engines having other numbers of cylinders, having other cylinder arrangements (in line, opposing, etc.), and operating on other combustion principles (e.g., crankcase compression, two-stroke or rotary) can be used in other embodiments.  
         [0023]    As used in this description, the term “horizontally” means that members or components extend generally and parallel to the water surface (i.e., generally normal to the direction of gravity) when the associated watercraft  18  is substantially stationary with respect to the water surface and when the drive unit  12  is not tilted (i.e., as shown in FIG. 1). The term “vertically” in turn means that proportions, members or components extend generally normal to those that extend horizontally.  
         [0024]    A movable member, such as a reciprocating piston, moves relative to the cylinder block  40  in a suitable manner. In the illustrated arrangement, a piston (not shown) reciprocates within each cylinder bore. Because the cylinder block  40  is split into the two cylinder banks, each cylinder bank extends outward at an angle to an independent first end in the illustrated arrangement. A pair of cylinder head members  42  are fixed to the respective first ends of the cylinder banks to close those ends of the cylinder bores. The cylinder head members  42  together with the associated pistons and cylinder bores provide six combustion chambers (not shown). Of course, the number of combustion chambers can vary, as indicated above. Each of the cylinder head member  42  is covered with the cylinder head cover member  44 .  
         [0025]    A crankcase member  46  is coupled with the cylinder block  40  and a crankcase cover member  48  is further coupled with a crankcase member  46 . The crankcase member  46  and a crankcase cover member  48  close the other end of the cylinder bores and, together with the cylinder block  40 , define the crankcase chamber. Crankshaft  50  extends generally vertically through the crankcase chamber and journaled for rotation about a rotational axis by several bearing blocks. Connecting rods couple the crankshaft  50  with the respective pistons in any suitable manner. Thus, a reciprocal movement of the pistons rotates the crankshaft  50 .  
         [0026]    With reference again to FIG. 1, the driveshaft housing  24  depends from the power head  20  to support a drive shaft  52 , which is coupled with crankshaft  50  and which extends generally vertically through driveshaft housing  24 . A driveshaft  52  is journaled for rotation and is driven by the crankshaft  50 .  
         [0027]    The lower unit  26  depends from the driveshaft housing  24  and supports a propulsion shaft  54  that is driven by the driveshaft  52  through a transmission unit  56 . A propulsion device is attached to the propulsion shaft  54 . In the illustrated arrangement, the propulsion device is the propeller  57  that is fixed to the transmission unit  56 . The propulsion device, however, can take the form of a dual counter-rotating system, a hydrodynamic jet, or any of a number of other suitable propulsion devices.  
         [0028]    Preferably, at least three major engine portions  40 ,  42 ,  44 ,  46 , and  48  are made of aluminum alloy. In some arrangements, the cylinder head cover members  44  can be unitarily formed with the respective cylinder members  42 . Also, the crankcase cover member  48  can be unitarily formed with the crankcase member  46 .  
         [0029]    The engine  28  also comprises an air intake system  58 . The air intake system  58  draws air from within the cavity  32  to the combustion chambers. The air intake system  58  shown comprises six intake passages  60  and a pair of plenum chambers  62 . In the illustrated arrangement, each cylinder bank communicates with three intake passages  60  and one plenum chamber  62 .  
         [0030]    The most downstream portions of the intake passages  60  are defined within the cylinder head member  42  as inner intake passages. The inner intake passages communicate with the combustion chambers through intake ports, which are formed at inner surfaces of the cylinder head members  42 . Typically, each of the combustion chambers has one or more intake ports. Intake valves are slidably disposed at each cylinder head member  42  to move between an open position and a closed position. As such, the valves act to open and close the ports to control the flow of air into the combustion chamber. Biasing members, such as springs, are used to urge the intake valves toward their respective closed positions by acting between a mounting boss formed on each cylinder head member  42  and a corresponding retainer that is affixed to each of the valves. When each intake valve is in the open position, the inner intake passage thus associated with the intake port communicates with the associated combustion chamber.  
         [0031]    Other portions of the intake passages  60 , which are disposed outside of the cylinder head members  42 , preferably are defined with intake conduits  64 . In the illustrated arrangement, each intake conduit  64  is formed with two pieces. One piece is a throttle body  66 , in which a throttle valve assembly  68  is positioned. Throttle valve assemblies  68  are schematically illustrated in FIG. 2. The throttle bodies  66  are connected to the inner intake passages. Another piece is an intake runner  70  disposed upstream of the throttle body  66 . The respective intake conduit  64  extend forwardly alongside surfaces of the engine  28  on both the port side and the starboard side from the respective cylinder head members  42  to the front of the crankcase cover member  48 . The intake conduits  64  on the same side extend generally and parallel to each other and are vertically spaced apart from one another.  
         [0032]    Each throttle valve assembly  68  preferably includes a throttle valve. Preferably, the throttle valves are butterfly valves that have valve shafts journaled for pivotal movement about generally vertical axis. In some arrangements, the valve shafts are linked together and are connected to a control linkage. The control linkage is connected to an operational member, such as a throttle lever, that is provided on the watercraft or otherwise proximate the operator of the watercraft  18 . The operator can control the opening degree of the throttle valves in accordance with operator request through the control linkage. That is, the throttle valve assembly  68  can measure or regulate amounts of air that flow through intake passages  60  through the combustion chambers in response to the operation of the operational member by the operator. Normally, the greater the opening degree, the higher the rate of air flow and the higher the engine speed. An idle speed control (ISC) valve  71  bypasses the throttle body  66  and allows for the regulation of air to the engine in order to govern the engine idle speed.  
         [0033]    The respective plenum chambers  62  are connected with each other through one or more connecting pipes  72  (FIG. 3) to substantially equalize the internal pressures within each chamber  62 . The plenum chambers  62  coordinate or smooth air delivered to each intake passage  60  and also act as silencers to reduce intake noise.  
         [0034]    The air within the closed cavity  32  is drawn into the plenum chamber  62 . The air expands within the plenum chamber  62  to reduce pulsations and then enters the outer intake passages  60 . The air passes through the outer intake passage  60  and flows into the inner intake passages. The throttle valve assembly  68  measures the level of airflow before the air enters into the inner intake passages.  
         [0035]    The engine  28  further includes an exhaust system that routes burnt charges, i.e., exhaust gases, to a location outside of the outboard motor  10 . Each cylinder head member  42  defines a set of inner exhaust passages that communicate with the combustion chambers to one or more exhaust ports which may be defined at the inner surfaces of the respective cylinder head members  42 . The exhaust ports can be selectively opened and closed by exhaust valves. The construction of each exhaust valve and the arrangement of the exhaust valves are substantially the same as the intake valve and the arrangement thereof, respectively. Thus, further description of these components is deemed unnecessary.  
         [0036]    Exhaust manifolds preferably are defined generally vertically with the cylinder block  40  between the cylinder bores of both the cylinder banks. The exhaust manifolds communicate with the combustion chambers through the inner exhaust passages and the exhaust ports to collect the exhaust gas therefrom. The exhaust manifolds are coupled with the exhaust discharge passage of the exhaust guide member  38 . When the exhaust ports are opened, the combustion chambers communicate with the exhaust discharge passage through the exhaust manifolds. A valve cam mechanism preferably is provided for actuating the intake and exhaust valves in each cylinder bank. In the embodiment shown, the valve cam mechanism includes second rotatable members such as a pair of camshafts  74  per cylinder bank. The camshafts  74  typically comprise intake and exhaust camshafts that extend generally vertically and are journaled for rotation between the cylinder head members  42  and the cylinder head cover members  44 . The camshafts  74  have cam lobes (not shown) to push valve lifters that are fixed to the respective ends of the intake and exhaust valves in any suitable manner. Cam lobes repeatedly push the valve lifters in a timely manner, which is in proportion to the engine speed. The movement of the lifters generally is timed by rotation of the camshaft  74  to appropriately actuate the intake and exhaust valves.  
         [0037]    The camshaft drive mechanism  76  preferably is provided for driving the valve cam mechanism. The camshaft drive mechanism  76  in the illustrated arrangement is formed above a top surface  78  (see FIG. 2) of the engine  28  and includes driven sprockets  80  positioned atop at least one of each pair of camshafts  74 , a drive sprocket  82  positioned atop the crankshaft  50  and the flexible transmitter, such as a timing belt or chain  84 , for instance, wound around the driven sprockets  80  and the drive sprocket  82 . The crankshaft  50  thus drives the respective crankshaft  74  through the time belt  84  in the timed relationship.  
         [0038]    The illustrated engine  28  further includes indirect, port or intake passage fuel injection. In one arrangement, the engine  28  comprises fuel injection and, in another arrangement, the engine  28  is carburated. The illustrated fuel injection system shown includes six fuel injectors  86  with one fuel injector allotted to each one of the respective combustion chambers. The fuel injectors  86  preferably are mounted on the throttle body  66  of the respective banks.  
         [0039]    Each fuel injector  86  has advantageously an injection nozzle directed downstream within the associated intake passage  60 . The injection nozzle preferably is disposed downstream of the throttle valve assembly  60 . The fuel injectors  86  spray fuel into the intake passages  60  under control of an electronic control unit (ECU)  88  (FIG. 4). The ECU  88  controls both the initiation, timing and the duration of the fuel injection cycle of the fuel injector  86  so that the nozzle spray a desired amount of fuel for each combustion cycle.  
         [0040]    A vapor separator  90  preferably is in full communication with the tank and the fuel rails, and can be disposed along the conduits in one arrangement. The vapor separator  90  separates vapor from the fuel and can be mounted on the engine  28  at the side service of the port side.  
         [0041]    The fuel injection system preferably employs at least two fuel pumps to deliver the fuel to the vapor separator  90  and to send out the fuel therefrom. More specifically, in the illustrated arrangement, a lower pressure pump  92 , which is affixed to the vapor separator  90 , pressurizes the fuel toward the vapor separator  90  and the high pressure pump (not shown), which is disposed within the vapor separator  90 , pressurizes the fuel passing out of the fuel separator  90 .  
         [0042]    A vapor delivery conduit  94  couples the vapor separator  90  with at least one of the plenum chambers  62 . The vapor removed from the fuel supply by the vapor separator  90  thus can be delivered to the plenum chambers  62  for delivery to the combustion chambers with the combustion air. In other applications, the engine  28  can be provided with a ventilation system arranged to send lubricant vapor to the plenum chamber(s). In such applications, the fuel vapor also can be sent to the plenum chambers via the ventilation system.  
         [0043]    The engine  28  further includes an ignition system. Each combustion chamber is provided with a spark plug  96  (see FIG. 4), advantageously disposed between the intake and exhaust valves. Each spark plug  96  has electrodes that are exposed in the associated combustion chamber. The electrodes are spaced apart from each other by a small gap. The spark plugs  96  are connected to the ECU  88  through ignition coils  98 . One or more ignition triggering sensors  100  are positioned around a flywheel assembly  102  to trigger the ignition coils, which in return trigger the spark plugs  96 . The spark plugs  96  generate a spark between the electrodes to ignite an air/fuel charge in the combustion chamber according to desired ignition timing maps or other forms of controls.  
         [0044]    Generally, during an intake stroke, air is drawn into the combustion chambers through the air intake passages  60  and fuel is mixed with the air by the fuel injectors  86 . The mixed air/fuel charge is introduced to the combustion chambers. The mixture is then compressed during the compression stroke. Just prior to a power stroke, the respective spark plugs ignite the compressed air/fuel charge in the respective combustion chambers. The air/fuel charge thus rapidly burns during the power stroke to move the pistons. The burnt charge, i.e., exhaust gases, then is discharged from the combustion chambers during an exhaust stroke.  
         [0045]    The illustrated engine further comprises a lubrication system to lubricate the moving parts within the engine  28 . The lubrication system is a pressure fed system where the correct pressure is important to adequately lubricate the bearings and other rotating surfaces. The lubrication oil is delivered under pressure through an oil filter  104  and then dispersed throughout the engine to lubricate the internal moving parts.  
         [0046]    The flywheel assembly  102 , which is schematically illustrated with phantom line in FIG. 3, preferably is positioned atop the crankshaft  50  and is positioned for rotation with the crankshaft  50 . The flywheel assembly  102  advantageously includes a flywheel magneto for AC generator that supplies electric power directly or indirectly via a battery to various electrical components such as the fuel injection system, the ignition system and the ECU  88 . An engine cover  106  preferably extends over almost the entire engine  28 , including the flywheel assembly  102 .  
         [0047]    In the embodiment of FIG. 1, the driveshaft housing  24  defines an internal section of the exhaust system that leaves the majority of the exhaust gases to the lower unit  26 . The internal section includes an idle discharge portion that extends from a main portion of the internal section to discharge idle exhaust gases directly to the atmosphere through a discharge port that is formed on a rear surface of the driveshaft housing  24 .  
         [0048]    Lower unit  26  also defines an internal section of the exhaust system that is connected with the internal exhaust section of the driveshaft housing  24 . At engine speeds above idle, the exhaust gases are generally discharged to the body of water surrounding the outboard motor  10  through the internal sections and then a discharge section defined within the hub of the propeller  57 .  
         [0049]    The engine  28  may include other systems, mechanisms, devices, accessories, and components other than those described above such as, for example, a cooling system. The crankshaft  50  through a flexible transmitter, such as timing belt  84  can directly or indirectly drive those systems, mechanisms, devices, accessories, and components.  
       The Engine Control System  
       [0050]    Successful engine starting in various different environments is highly desirable and requires accurate response and adjustments of the controlling engine parameters. The present invention provides an engine control routine to accommodate successful engine starting regardless of a cold or warm engine.  
         [0051]    During a warm engine start environment it is possible that fuel vapors from the vapor separator  90 , caused by warm engine temperatures, collect in the plenum chambers  62  through the vapor delivery conduit  94 . These collected fuel vapors provide a rich air/fuel mixture upon a warm engine starting period. The engine control routine of the present invention accommodates for such a richer than normal air/fuel mixture during starting.  
         [0052]    As seen in FIG. 6, different graphs,  6   a ,  6   b ,  6   c ,  6   d  of various engine parameters are shown. Each graph represents an engine parameter before engine starting, during engine starting, and directly after engine starting all with reference to time.  
         [0053]    Referring to FIG. 5, in one embodiment, the engine control system incorporates an engine temperature sensor  108  located in the engine block  40  as well as cylinder head temperature sensors  110 ,  112  in each cylinder head member  42  to transmit to the ECU  88  signals corresponding to engine and individual cylinder head temperatures. An audible alarm  111  and a visual alarm  113  are activated when the cylinder head temperature sensors  110 , 112  or the engine temperature sensor detect an overheating temperature of the engine  28 . When an overheating temperature of the engine  28  is detected, the ECU  88  initiates an engine overheat control whereby the engine speed is lowered be reducing the fuel injection amount or retarding the ignition timing.  
         [0054]    As seen in FIG. 4, the ECU  88  is programmed to perform methods for accurately evaluating and adjusting parameters of the engine  28 . Through the ignition triggering sensors  100  along with an engine speed determination method  114 , the engine speed can be calculated. Other methods include a warm-start determination method  116  as well as a starting mode determination method  118 .  
         [0055]    Through the information acquired from the engine temperature sensors  108 ,  110 ,  112 , and the combination of the methods  114 ,  116 ,  118 , the ECU  88  accurately provides for a smooth, safe engine start and running condition.  
         [0056]    [0056]FIG. 6 a  shows the ignition timing curve of the engine control system. Before and during engine starting the ignition timing is set at a retarded value to ease cranking and allow for a quick, easy engine start. After engine starting, the ignition value follows an advance curve  120  to raise the engine speed and improve engine responsiveness. The ignition advance value range  122  after engine starting and during an idle speed can also be seen.  
         [0057]    [0057]FIG. 6 b  shows the amount of fuel injected during a period from before starting until an idle speed is reached. A time duration  124  represents how long fuel is injected at a specific amount while the engine is starting. This amount of fuel injected decreases as seen by the curves  126  and  128 . The curve  126  represents a decrease in fuel injected after a cold engine start whereas the curve  128  represents a decrease in fuel injected after a warm engine start. A total fuel injection reduction range  130  can also be seen.  
         [0058]    [0058]FIG. 6 c  represents the operation of the ISC valve  71 . Initially, the ISC valve is opened during the starting period after the ignition power switch is turned on. After the starting period at a point  132 , the ISC valve  71  begins to close and regulate the additional air allowed to the engine. When the engine speed has reached a predetermined idle speed, at point  134  the ISC valve continuously changes its opening to properly regulate the engine speed.  
         [0059]    [0059]FIG. 6 d  represents the engine speed in revolutions per minute (RPM). As the engine speed rises, it reaches an engine start determination speed  136  where the ECU  88  determines that the engine  28  has reaches a speed, e.g. 500 RPM, that represents a successful engine start. The engine speed continues to rise and finally settles to a steady predetermined idle speed  138 .  
         [0060]    [0060]FIG. 7 shows a control routine  150  implemented by ECU  88  arranged and configured in accordance with certain features, aspects, and advantages of the present invention. The control routine  150  begins and moves to a first decision block P 10  in which it is determined if the engine is starting. The engine  28  is considered to be in the starting mode starting if the engine is revolving at a speed less than or equal to a predetermined value. By way of specific example, 500 RPM or less can define the starting mode. If the engine is not being started, the control routine  150  returns to the block P 10 . If it is determined that the engine is starting, the control routine  150  moves to decision block P 12 .  
         [0061]    In decision block P 12 , it is determined if the engine is at a normal operating temperature. A normal operating temperature may be considered to be in the range of 80 degrees Celsius. If, in decision block P 12  it is determined that the engine is not at a normal operating temperature, the control routine moves to operation block P 14 . If, however, in decision block P 12  it is determined that the engine is at a normal operating temperature, the control routine moves to operation block P 16 .  
         [0062]    In operation block P 14 , a cold engine start control is initiated. In such a cold engine start control, various aspects of engine management are initiated such as longer fuel injection duration. The control routine  150  then moves to decision block P 18 .  
         [0063]    In operation block P 16 , a warm engine start control operation is initiated. In such a warm engine start control, various aspects of engine management are initiated such as shorter fuel injection duration as described above and shown in FIG. 6 b . The control routine  150  then moves to decision block P 18 .  
         [0064]    In decision block P 18  it is determined if the engine has started. The engine is started if the engine rpm is above 500 rpm or greater. If in decision block P 18  it is determined that the engine has not started, e.g., the engine rpm is less than 500 rpm, the control routine moves back to decision block P 12 . If, however, in decision block P 18  it is determined that the engine has started, e.g., the engine rpm is above 500 rpm, the control routine then moves to decision block P 20 .  
         [0065]    In decision block P 20 , it is determined if the engine is at a normal operating temperature. Normal operating temperature can be classified as a temperature in the range of 80 degrees Celsius. If, in decision block P 20  it is determined that the engine is not at a normal operating temperature, the control routine moves to operation block P 22 . If, however, in decision block P 20  it is determined that the engine is at a normal operating temperature, the control routine moves to operation block P 24 .  
         [0066]    In operation block P 22 , a cold engine operation control procedure is initiated. Such a cold engine operation control involves compensating various engine control parameters in order to allow the engine to run smoothly at a decreased engine temperature.  
         [0067]    In operation block P 24 , a warm engine operation control procedure is initiated. Such a warm engine operation control involves compensating various engine parameters in order to allow the engine to run successfully and smoothly at an increased engine temperature. The control routine  150  then returns.  
         [0068]    It is to be noted that the control system described above may be in the form of a hard-wired feedback control circuit in some configurations. Alternatively, the control system may be constructed of a dedicated processor and memory for storing a computer program configured to perform the steps described above in the context of the flowchart. Additionally, the control systems may be constructed of a general-purpose computer having a general-purpose processor and memory for storing the computer program for performing the routine. Preferably, however, the control system are incorporated into the ECU  110 , in any of the above-mentioned forms.  
         [0069]    Although the present invention has been described in terms of a certain preferred embodiments, other embodiments apparent to those of ordinary skill in the art also are within the scope of this invention. Thus, various changes and modifications may be made without departing from the spirit and scope of the invention. For instance, various steps within the routines may be combined, separated, or reordered. In addition, some of the indicators sensed (e.g., engine speed and throttle position) to determine certain operating conditions (e.g., rapid deceleration) can be replaced by other indicators of the same or similar operating conditions. Moreover, not all of the features, aspects and advantages are necessarily required to practice the present invention. Accordingly, the scope of the present invention is intended to be defined only by the claims that follow.