Engine control unit for water vehicle

Abstract

A watercraft includes a performance mode selector which enables a rider to select normal operation of the watercraft or an economy mode operation. In the economy mode operation, the watercraft either disables cylinders or reduces fuel injection and ignition in order to limit the maximum engine speed obtained by the engine when the throttle lever is fully depressed Additionally, the watercraft can disable cylinders or selectively reduce fuel injection or ignition when an abnormal operating parameter has been detected.

What is claimed is:  
     
         1 . A watercraft comprising a hull defining an engine compartment, an engine disposed in the engine compartment, a rider's area supported by the hull, a throttle lever disposed in the rider's area, a controller configured to control fuel supply and ignition for engine operation, a user-operable performance mode switch having a normal operation position and an economy mode position, the controller being configured to limit engine speed through at least one of cylinder disablement, fuel injection reduction, and ignition reduction, to a predetermined engine speed which is less than the maximum rated speed of the engine when the performance mode switch is in the economy mode position.  
     
     
         2 . The watercraft according to  claim 1 , wherein the controller is configured to disable a cylinder for a predetermined time, then change the disabled cylinder to a different cylinder.  
     
     
         3 . The watercraft according to  claim 1 , wherein the engine includes at least a first and second cylinders, the controller being configured to disable the first cylinder for a predetermined time, then enable the first cylinder and disable the second cylinder after the predetermined time has elapsed.  
     
     
         4 . The watercraft according to  claim 1 , wherein the controller is configured to determine whether an operational parameter of the engine is outside a range of normal operational values, and to limit engine speed through at least one of cylinder disablement, fuel injection reduction, and ignition reduction, to a predetermined engine speed which is less than the maximum rated speed of the engine when the operational parameter is outside the range of normal operational values.  
     
     
         5 . The watercraft according to  claim 4 , wherein the operational parameter is engine temperature and the range of normal operational values is the normal operating temperature of the engine.  
     
     
         6 . The watercraft according to  claim 4 , wherein the controller is configured to increase at least one of the number of disabled cylinders, the reduction of fuel injection, and the reduction of ignition when a second operational parameter of the engine exceeds a predetermined value.  
     
     
         7 . The watercraft according to  claim 6 , wherein the second operational parameter is a speed of the engine.  
     
     
         8 . The watercraft according to  claim 1 , wherein the engine includes a plurality of cylinders, the controller being configured to group the cylinders into at least two groups and to alternately disable the groups of cylinders when the performance mode switch is in the economy mode position.  
     
     
         9 . The watercraft according to  claim 1 , wherein the controller is configured to reduce fuel injection frequency by a first factor when a speed of the engine exceeds the first predetermined engine speed.  
     
     
         10 . The watercraft according to  claim 9 , wherein the controller is configured to reduce fuel injection frequency by a second factor, which is less than the first factor, when the speed of the engine exceeds a second predetermined speed.  
     
     
         11 . A method of controlling an engine of a watercraft having an engine and a user-operable performance mode switch, the method comprising determining if the performance mode switch is in a first or second position, limiting engine speed to a first predetermined speed with at least one of cylinder disablement, fuel injection reduction, and ignition reduction when the performance mode switch is in the first position.  
     
     
         12 . The method as set forth in  claim 11 , wherein the step of cylinder disablement comprises supplying fuel to the first cylinder and preventing the supply of fuel to a first cylinder for a predetermined time.  
     
     
         13 . The method as set forth in  claim 12  additionally comprising supplying fuel to the first cylinder and preventing the supply of fuel to the second cylinder after the predetermined time period has elapsed.  
     
     
         14 . The method as set forth in  claim 11 , wherein the step of fuel injection reduction comprises reducing the frequency of fuel injection such that fuel is not supplied to a cylinder during an intake stroke of a piston reciprocating in the cylinder.  
     
     
         15 . The method as set forth in  claim 11 , wherein the step of fuel injection reduction comprises reducing the frequency of fuel injection below the frequency of fuel injection used during normal operation.  
     
     
         16 . A watercraft comprising a hull defining an engine compartment, an engine disposed in the engine compartment, a rider's area supported by the hull, a throttle lever disposed in the rider's area, a controller configured to control fuel supply and ignition for engine operation, a user-operable performance mode switch having a normal operation position and an economy mode position, and means for limiting engine speed to a predetermined engine speed which is less than the maximum rated speed of the engine when the performance mode switch is in the economy mode position.  
     
     
         17 . A watercraft comprising a hull defining an engine compartment, an engine disposed in the engine compartment, a controller configured to control fuel supply and ignition for engine operation, the controller being configured to detect an operational parameter of the engine and to disable a first cylinder of the engine when a speed of the engine is above a predetermined engine speed and when the operation parameter is outside a normal range of values, the controller also being configured to increase the number of disabled cylinders if the speed of the engine continues to be greater than the predetermined engine speed.  
     
     
         18 . The watercraft as set forth in  claim 17  wherein the controller is configured to decrease the number of disabled cylinders when the engine speed is below the predetermined engine speed.  
     
     
         19 . The watercraft as set forth in  claim 17 , wherein the controller is configured to disable a second cylinder and enable the first cylinder after a predetermined time has elapsed.  
     
     
         20 . The watercraft as set forth in  claim 17 , wherein the operational parameter of the engine is a temperature of the engine.  
     
     
         21 . A method of controlling a watercraft engine comprising detecting an operational parameter of the engine, disabling a first cylinder if a speed of the engine is above a predetermined speed, and increasing the number of disabled cylinders if the engine speed continues to be higher than the predetermined speed.  
     
     
         22 . The method as set forth in  claim 21  additionally comprising decreasing the number of disabled cylinders when the engine speed is below the predetermined engine speed.  
     
     
         23 . The method as set forth in  claim 21  additionally comprising disabling a second cylinder and enabling the first cylinder after a predetermined time has elapsed.  
     
     
         24 . The method as set forth in  claim 21 , wherein disabling the first cylinder comprises preventing fuel supply to the first cylinder.  
     
     
         25 . The method as set forth in  claim 21  wherein detecting an operational parameter comprises detecting a temperature of the engine.