Abstract:
A service alarm system for a boat propulsion unit monitors a lubricant service life. The system informs the watercraft operator when the lubricant is no longer suitable to provide proper lubricating properties for the boat propulsion unit. The alarm system informs the operator by sounding an audible alarm or illuminating a visual alarm through at least one light. By informing the operator inadequate lubrication properties, the user can perform proper service of the watercraft to ensure safe and enjoyable watercraft operation.

Description:
PRIORITY INFORMATION  
         [0001]    This application is based on and claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2002-318768, filed on Oct. 31, 2002, the entire contents of which are hereby expressly incorporated by reference herein.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The invention relates to a watercraft service alarm system for monitoring a lubrication service interval. The system informs the watercraft operator when the lubrication service interval has expired according to a predetermined time duration.  
           [0004]    2. Description of the Related Art  
           [0005]    Watercraft (e.g., personal watercraft or boats) typically incorporate internal combustion engines along with propulsion units to provide power and propel the watercraft in a variety of popular applications. The internal combustion engines can operate according to the two-cycle (two-stroke) operating principle or the four-cycle (four-stroke) operating principle. Internal combustion engines use lubricants to lubricate various engine components allowing the engine to operate correctly and provide a long service life.  
           [0006]    Although modern lubricants do retain their lubricating properties for extended lengths of time, lubricants do have a limited service period. Before the lubricant begins to lose its operating properties, the lubricant must be renewed to continue providing the internal combustion engine with adequate lubricating properties.  
           [0007]    It is possible that the operator of the watercraft forgets to renew the lubricant in the internal combustion engine, therefore a need exists for an improved lubrication service alarm that reminds the operator of the proper time to renew the lubricant in the internal combustion engine.  
         SUMMARY OF THE INVENTION  
         [0008]    It is an object of this invention to provide a            
           [0009]    One aspect of an embodiment in accordance with the present invention is a            
           [0010]    Another aspect in accordance with embodiments of the present invention is a           
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    Preferred embodiments in accordance with aspects of the present invention will be described below in connection with the accompanying drawing figures in which:  
         [0012]    [0012]FIG. 1 illustrates a side view of a watercraft with an outboard motor including a lubrication service alarm;  
         [0013]    [0013]FIG. 2 illustrates a block diagram illustrating various communication paths and components of a watercraft service control system;  
         [0014]    [0014]FIG. 3 illustrates a front view of a display panel that shows a switch, alarm lights, and reset buttons;  
         [0015]    [0015]FIG. 4 illustrates a flowchart of a control routine performed by the watercraft service control system that illustrates control of a service alarm;  
         [0016]    [0016]FIG. 5 illustrates another front view of a display panel that shows a switch, an alarm light, and a reset button;  
         [0017]    [0017]FIG. 6 illustrates another front view of a display panel that shows a switch and a plurality of alarm lights, and  
         [0018]    [0018]FIG. 7 illustrates another front view of a display panel that shows a switch and an alarm light.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]    [0019]FIG. 1 shows a watercraft  10  equipped with a service control system  11  (FIG. 2) that comprises a lubrication service interval warning device and a system for reminding the operator of a lubrication service interval. The watercraft comprises a hull  12  and an outboard motor  14 . The outboard motor  14  includes an engine  16  that drives a propeller  18  through a transmission (not shown).  
         [0020]    The engine  16  in the illustrated embodiment preferably operates on a four-cycle combustion principle. The engine  16  has a cylinder block (not shown). The presently preferred cylinder block defines at least on cylinder bore (not shown). When more than one cylinder bore is defined, the cylinder bores extend generally horizontally and are generally vertically spaced from one another. As used in this description, the term “horizontally” means that the subject portions, members or components extend generally in parallel to the water line (not shown) when the associated watercraft  10  is substantially stationary with respect to the water line and when a drive unit (not shown) is not tilted. The term “vertically” in turn means that portions, members or components extend generally normal to those that extend horizontally.  
         [0021]    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 and having other cylinder arrangements (V, W, opposing, etc.) 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. Regardless of the particular construction, the engine preferably comprises an engine body that includes at least one cylinder bore.  
         [0022]    The engine  16  also comprises an air induction system or device (not shown). The air induction system draws air from within a cavity (not shown) to at least one combustion chamber (not shown). The air induction system preferably comprises at least one intake passage (not shown). Each cylinder bore preferably has at least one intake port (not shown) defined in a cylinder head member (not shown). The intake port can be selectively opened and closed by at least one intake valve (not shown).  
         [0023]    The engine  16  also comprises an exhaust system that guides burnt charges, i.e., exhaust gases, to a location outside of the outboard motor  14 . Each cylinder bore preferably has at least one exhaust port (not shown) defined in the cylinder head member. The exhaust port can be selectively opened and closed by at least one exhaust valve (not shown). The construction of each exhaust valve and the arrangement of the exhaust valve are substantially the same as the intake valve and the arrangement thereof, respectively.  
         [0024]    An exhaust manifold (not shown) preferably is disposed next to the exhaust port and extends generally vertically. The exhaust manifold communicates with the combustion chamber through the exhaust ports to collect exhaust gases therefrom. The exhaust manifold is coupled with an exhaust passage of an exhaust guide member (not shown). When the exhaust port is opened, the combustion chamber communicates with the exhaust passage through the exhaust manifold.  
         [0025]    The engine  16  preferably has a carburetor or a fuel injection system. The fuel injection system can be a port or a manifold fuel injection system. The fuel injection system preferably comprises at least one fuel injector (not shown) with one fuel injector allotted for each of the respective combustion chambers through suitable fuel conduits. Each fuel injector preferably has an injection nozzle directed toward the associated intake passage adjacent to the intake ports.  
         [0026]    The engine  16  further comprises an ignition or firing system. An electronic control unit (ECU)  22  controls various aspects of the engine  16 . Each combustion chamber is provided with at least one spark plug (not shown) that is connected to the ECU  22  through an igniter (not shown) so that ignition timing is also controlled by the ECU  22 . Each spark plug or igniter has electrodes that are exposed into the associated combustion chamber and are spaced apart from each other with a small gap. The spark plug generates a spark between the electrodes to ignite an air/fuel charge in the combustion chamber at selected ignition timing under control of the ECU  22 .  
         [0027]    In the illustrated engine  16 , at least one piston (not shown) reciprocates between top dead center and bottom dead center. When a crankshaft (not shown) makes two rotations, the piston generally moves 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, at least one camshaft (not shown) makes one rotation and actuates the intake valve and the exhaust valve to open the intake ports during the intake stroke and to open exhaust ports during the exhaust stroke, respectively.  
         [0028]    During engine operation, heat builds in the engine  16 . The illustrated engine  16  thus includes a cooling system to cool the engine  16 . The outboard motor  14  preferably employs an open-loop type water cooling system that introduces cooling water from the body of water surrounding the outboard motor  14  and then discharges the water to the body of water. The cooling system includes one or more water jackets defined within the engine  16  through which the water travels to remove heat from the engine  16 .  
         [0029]    The engine  16  also preferably includes a lubrication system. A closed-loop type system preferably is employed in the illustrated embodiment. The lubrication system comprises a lubricant tank defining a reservoir, which preferably is positioned within a driveshaft housing (not shown). An oil pump (not shown) is provided at a desired location, such as atop the driveshaft housing, 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. The engine portions that need lubrication include, for example, but not limited to crankshaft bearings (not shown), connecting rods (not shown) and the pistons. Lubricant return passages (not shown) also are provided to return the oil to the lubricant tank for re-circulation. The lubrication system includes the service control system  11 , which will be described in greater detail below.  
         [0030]    The transmission preferably is provided between a driveshaft (not shown) and a propulsion shaft (not shown), which lie generally normal to each other (i.e., at a 90° shaft angle) to couple together the two shafts by bevel gears. The transmission includes a switchover mechanism (not shown) that is configured to change a rotational direction of the propeller  18  between forward, neutral or reverse. The switchover mechanism typically comprises a dog clutch and a shift unit that operates the dog clutch. At the forward and reverse positions, which are propulsion positions, the propeller  18  propels the watercraft  10  forward and backward, respectively. At the neutral position, which is a-non-propulsion position, the propeller  18  does not propel the watercraft  10  because the propulsion shaft is disconnected from the driveshaft.  
         [0031]    Preferably, the switchover mechanism is interconnected with a throttle valve linkage (not shown). A single control lever, which is the foregoing throttle lever, is connected to not only a throttle valve (not shown) but also to the switchover mechanism. The single control lever therefore controls both the throttle valve and the switchover mechanism in an interrelationship such that the throttle valve is always closed (or almost closed) when the transmission is placed in the neutral position by the switchover mechanism. The throttle linkage can be released from the switchover mechanism for an engine revving operation.  
         [0032]    With reference to FIG. 2, the service control system  11  is shown. Along with the engine  16  the outboard motor  14  includes a generator  24 , a rectifier  26 , an ignition unit or module  28 , and a tachometer signal unit or module  16 . The ECU  22  includes a central processing unit (CPU)  34 ; at least two memory allocations comprising a random access memory (RAM)  36  and an electrically erasable programmable read-only memory (EEPROM)  38 . A lubricant service timer  42  records the engine  16  run time, i.e. the time that the engine  16  is actually being operated.  
         [0033]    The hull  12  also includes a display unit  44  (FIGS. 3 and 5- 7 ) that includes a main switch  46 . The main switch  46  generally starts or stops the engine  16  through a key (not shown). When the main switch  46  is closed, a starter relay (not shown) transfers a voltage from a battery (not shown) to activate a starter motor (not shown) to initiate engine operation. An engine stop switch (not shown) can cause the ECU  22  to cease engine operation. The watercraft  10  may also include other systems for controlling when the engine is stopped, as is well known by persons skilled in the art.  
         [0034]    The battery also supplies power to other various watercraft components. The battery is charged by the generator  24  mounted on the engine  16 . The generator  24  delivers an AC output voltage to the rectifier  26  to supply the battery with a rectified DC input voltage.  
         [0035]    With reference to FIG. 3, the display unit  44  is shown. One preferred embodiment of the display unit  44  comprises at least one service alarm light  50 , a service alarm light reset button  52  to reset the service alarm light  50 , a lubricant level warning light  54 , and a lubricant level warning light reset button  56  to reset the lubricant level warning light  54 .  
         [0036]    When the amount of lubricant inside the engine  16  falls below a predetermined level the lubricant level warning light  54  illuminates informing the operator that an insufficient amount of lubricant is present in the engine  16 . An insufficient amount of lubricant inside the engine  16  can cause harm to engine surfaces that require lubrication to operate such as, but not limited to bearings, pistons, and cylinders. The lubricant level warning light reset button  56  allows the operator of the watercraft  10  to confirm that there is an insufficient amount of lubricant inside the engine  10  and to turn off the lubrication level warning light  54 . Turning off the lubrication level warning light  54  not only allows the operator to confirm the insufficient amount of lubricant inside the engine  16 , it also allows the operator to operate the watercraft safely by preventing any distraction from the lubrication level warning light  54 .  
         [0037]    The lubrication level warning light  54  can be initiated at any time when the lubricant level is too low. The lubrication level warning light  54  can also be initiated or for a predetermined amount of time during engine starting when the lubricant level is too low. Alerting the operator for a predetermined amount of time every time during starting that the lubricant level is too low consistently reminds the operator to remedy the low lubricant level.  
         [0038]    The service alarm light  50  allows the operator to be reminded when the lubricant should be renewed. When the engine  16  is running the tachometer signal device  32  sends a tachometer signal to the ECU  22 . The ECU  22  initiates the lubricant service timer  42  whenever the tachometer signal  32  is received. Therefore, whenever the engine  16  is running the lubricant service timer  42  records the amount of engine operating time. The ECU  22  stores the engine operating time data received from the lubricant service timer  42  in the RAM  36 . The ECU  22  then transfers the engine operating time data into the EEPROM  38 . The process with which the ECU  22  determines when to initiate the service alarm light  50  will be explained in further detail by a control routine  200  of FIG. 4.  
         [0039]    [0039]FIG. 4 illustrates a control routine  200  that it is arranged and configured in accordance with certain features, aspects, and advantages of the present invention. The control routine  200  begins at a first operation block P 10  an moves to an operation block P 12  where the total engine operating time stored in the EEPROM  38  is read and entered into the RAM  36 . The control routine  200  then moves to an operation block P 14 .  
         [0040]    In operation block P 14  the lubrication service alarm light  50  is activated according to the amount of stored engine operating time. For example, if the total amount of engine operating time stored in memory ranges from 0 to 33.3 hours, the alarm light  50  can flash once. If the total amount of engine operating time stored in memory ranges from 33.3 to 66.6 hours, the alarm light  50  can flash twice. If the total amount of engine operating time stored in memory ranges from 66.6 to 99.9 hours, the alarm light  50  can flash 3 times. The control routine  200  then moves to a decision block P 16 .  
         [0041]    In decision block P 16  it is determined if the timer reset button  52  has been pushed. In decision block P 16  if it is determined that the timer reset button  52  has been pushed, the control routine  200  moves to an operation block P 18 . If, however, in decision block P 16  it is determined that the timer reset button has not been pushed, the control routine  200  moves to a decision block P 22 .  
         [0042]    In operation block P 18  all timer values are cleared from all memory. The memory can now accept new engine operating time from a new lubrication time interval. The control routine then moves to an operation block P 20  where the lubrication alarm light  50  is turned off. The control routine  200  then returns to decision block P 16 .  
         [0043]    In decision block P 22  it is determined if the ECU  22  has received a tachometer signal from the tachometer signal device  32 . The signal received from the tachometer signal device  32  initiates from a signal received from the ignition unit  28 . The tachometer signal device takes the ignition signal from the ignition unit  28  and delivers a tachometer signal indicative of engine operation. In decision block P 22  if it is determined that the ECU  22  has not received the tachometer signal from the tachometer signal device  32 , i.e. the engine is not operating, the control routine  200  moves to a decision block P 32 .  
         [0044]    If, however, in decision block P 22  it is determined that the ignition has received a tachometer signal, i.e. the engine is running, the control routine  200  moves to a decision block P 24 .  
         [0045]    In decision block P 24  it is determined if a time T 1  has elapsed since the last time the total engine operating time was updated, i.e. the last time the ECU updated the total engine operating time in the RAM. Therefore, T 1  represents a time interval frequency when the engine operating time data is recorded to the RAM. The time T 1  can represent a predetermined amount of engine operating time, for example 10 milliseconds. If in decision block P 24  the time T 1  has not elapsed, the control routine bypasses an operation block P 26  to a decision block P 28 .  
         [0046]    If, however, in decision block P 24  it is determined that the time T 1  has elapsed, the control routine moves to the operation block P 26 .  
         [0047]    In operation block P 26  the time T 1  is added to the total engine operating time in memory (RAM). The control routine  200  then moves to a decision block P 28 .  
         [0048]    In decision block P 28  it is determined if a time T 2  has elapsed. T 2  can represent a time interval frequency when the engine operating time data is transferred from the RAM to the EEPROM. The time T 2  can represent a predetermined amount of engine operating time, for example 1 second. In decision block P 22  if the time T 2  has not elapsed, the control routine  200  moves to the decision block P 32 . If, however, in decision block P 28  it is determined that the time T 2  has elapsed, the control routine  200  moves to an operation block P 30 .  
         [0049]    In operation block P 30  the total engine operating time is saved into memory (EEPROM and RAM). The control routine  200  allows the total engine operating time to be constantly updated and preserved in the EEPROM. When the engine is shut off only the engine operating time recorded in the RAM memory is lost. The total amount of engine operating time located in the RAM that can be lost due to engine shut down is one second because T 2  represents a time period of one second. The control routine  200  then moves to the decision block P 32 .  
         [0050]    In decision block P 32  it is determined if the total number of operating hours equals 100 hours. In decision block P 32  if it is determined that the total number of operating hours does not equal 100 hours, the control routine  200  returns to the decision block P 16 .  
         [0051]    If, however, in decision block P 32  it is determined that the total number of operating hours does equal 100 hours, the control routine  200  moves to an operation block P 34  where the ECU  22  initiates the alarm light  50 . The control routine  200  then returns to the decision block P 16 .  
         [0052]    With reference to FIGS.  5 - 7 , various preferred embodiments of the display unit  44  will be described.  
         [0053]    The display unit  44  illustrated in FIG. 5 comprises the main switch  46 , a warning light  60  that can inform the operator when the lubricant level is below a predetermined level and when the total number of operating hours exceeds a predetermined amount, and a reset button  62 . The warning light  60  of the preferred embodiment of FIG. 5 can inform the operator of both the lubricant level and the total operating time of the engine through various possibilities including, but not limited to an audible alarm and/or a visual alarm. The visual alarm can comprise different color light emitting diodes (LED) (not shown) and a number of different flashing light frequencies. Using one warning light with numerous LEDs and/or different flashing frequencies allows for a simple, compact design and less expensive construction. The reset button  62  allows the operator to reset the total accumulated engine operating time after a lubricant service has been performed on the engine  16 .  
         [0054]    [0054]FIG. 6 illustrates another preferred embodiment of the display unit  44 . The display unit  44  comprises the main switch  46  and a lubricant warning light display  66 . The warning light display  66  comprises three different colored lights including, but not limited to a green light  68 , a yellow light  70 , and a red light  72 . As the predetermined lubricant service time period elapses, the different colored lights illuminate to inform the operator of the remaining time until a lubricant service is necessary.  
         [0055]    For example, when the operator turns the main switch  46  to start the engine  16  at least one light from the warning light display  66  illuminates. If a first predetermined lubricant time period has not yet elapsed the green light  68  can illuminate to inform the operator that the lubricant can still provide the engine with the required lubrication properties.  
         [0056]    If the first predetermined lubricant time period has elapsed, however a second predetermined lubricant time period has not elapsed, the yellow light  70  can illuminate. The illumination of the yellow light  70  can inform the operator that the lubricant can still provide the engine with required lubrication properties, however the lubricant is approaching a state where it will no longer be able to provide the engine with the required lubrication properties. During this predetermined lubricant time period the lubricant should be changed to continue to provide the engine  16  with the required lubrication properties.  
         [0057]    If the second predetermined lubricant time period has elapsed the red light  72  can illuminate to inform the operator that the lubricant no longer possesses the correct required lubrication properties for the engine  16 . When the red light  72  illuminates the lubricant should be renewed immediately to allow the engine to provide the operator with a long service life.  
         [0058]    [0058]FIG. 7 illustrates another preferred embodiment of the display unit  44 . The display unit  44  comprises the main switch  46  and a single lubricant warning light  76 . The single lubricant alarm light  76  can flash at different frequencies during a predetermined time period according to the amount of the predetermined lubricant time period that has already elapsed. For example, if a predetermined lubricant time period of 0 to 9 hours has not elapsed, the single lubricant alarm warning light  76  can flash once informing the operator that the lubricant can still provide the engine with the required lubrication properties.  
         [0059]    For a predetermined lubricant time period of 9-19 hours, the single lubricant warning light  76  can flash twice. The single warning lubricant light  76  flashing twice can inform the operator that the lubricant can still provide the engine with required lubrication properties, however the lubricant is approaching a state where it will no longer be able to provide the engine with the required lubrication properties.  
         [0060]    If the predetermined lubricant time period exceeds 19 hours, the single warning lubricant light  76  can inform the operator that the lubricant no longer possesses the correct required lubrication properties for the engine  16 . When the single lubricant alarm light  76  illuminates, the lubricant should be renewed immediately to allow the engine to provide the operator with a long service life.  
         [0061]    The length of the predetermined lubricant time periods can vary depending on the type of engine and the environment in which the engine is operated. The lubricant time periods described above are only some of the possible lubricant time periods and are not meant to limit the preferred embodiments of the present invention. Other lubricant time periods can be used and are dependent on manufacturer discretion.  
         [0062]    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.