Induction system for small watercraft

Abstract

An induction system for a 4-cycle engine of a small watercraft includes an improved construction that insulates the fuel injectors from engine-produced vibration and heat. The air induction system includes an air intake box defining the plenum chamber. The air intake box is supported from the engine by one or more stays. An insulating grommet is positioned between the air intake box and the stays. The air induction system also includes one or more throttle bodies within the plenum chamber which are connected to intake pipes external of the plenum chamber. The throttle bodies each support a fuel injector. Insulating sleeves are positioned between the throttle bodies and the intake pipes. Insulating rings are positioned between the throttle bodies and the air intake box.

What is claimed is:  
     
         1 . A watercraft comprising a hull defining an engine compartment, an internal combustion engine disposed in the engine compartment, the engine including an engine body defining a combustion chamber, an air induction system comprising an intake air chamber configured to guide air toward the combustion chamber, an electrical component disposed within the air chamber, and an insulating member supporting the air chamber relative to the engine body.  
     
     
         2 . The watercraft according to  claim 1 , wherein the electrical component is a fuel injector.  
     
     
         3 . The watercraft according to  claim 1  additionally comprising a throttle body connected to the air chamber, the engine body including at least one intake port, the insulating member comprising an elastic member connecting the throttle body to the intake port.  
     
     
         4 . The watercraft of  claim 3 , additionally comprising an intake runner extending from the intake port toward the throttle body, the elastic member connecting the intake runner to the throttle body.  
     
     
         5 . The watercraft of  claim 1  additionally comprising a throttle body having an outlet end, a collar connected to the outlet end of the throttle body, wherein the insulating member comprises an inlet end configured to engage the collar.  
     
     
         6 . The watercraft according to  claim 5 , when the throttle body is connected to the air chamber, the insulating member comprising an elastic member having an inlet end configured to engage the collar sufficiently to support at least part of the air chamber.  
     
     
         7 . The watercraft according to  claim 5 , wherein the inlet end of the insulating member comprises an annularly shaped channel configured to extend along an inner surface of the collar and an outer surface of the collar.  
     
     
         8 . The watercraft according to  claim 1  additionally comprising at least one stay extending from a portion of the engine body other than the intake port to the air chamber.  
     
     
         9 . The watercraft according to  claim 8  wherein the portion of the engine body comprises a cam chamber cover.  
     
     
         10 . The watercraft according to  claim 1 , wherein the insulating member is elastic.  
     
     
         11 . A marine-duty engine including an engine body defining a combustion chamber, an air induction system configured to guide air into the combustion chamber, the air induction system comprising an intake air chamber configured to guide intake air toward the combustion chamber, an electrical component disposed within the air chamber, and an insulating member connecting the air chamber with the engine body.  
     
     
         12 . The engine according to  claim 11 , wherein the electrical component is a fuel injector.  
     
     
         13 . The engine according to  claim 11  additionally comprising a throttle body connected to the air chamber, the engine body including at least one intake port, the insulating member comprising an elastic member connecting the throttle body to the intake port.  
     
     
         14 . The engine of  claim 13 , additionally comprising an intake runner extending from the intake port toward the throttle body, the elastic member connecting the intake runner to the throttle body.  
     
     
         15 . The engine of  claim 11  additionally comprising a throttle body having an outlet end, a collar connected to the outlet end of the throttle body, wherein the insulating member comprises an inlet end configured to engage the collar.  
     
     
         16 . The engine according to  claim 15 , when the throttle body is connected to the air chamber, the insulating member comprising an elastic member having an inlet end configured to engage the collar sufficiently to support at least part of the air chamber.  
     
     
         17 . The engine according to  claim 15 , wherein the inlet end of the insulating member comprises an annularly shaped channel configured to extend along an inner surface of the collar and an outer surface of the collar.  
     
     
         18 . The engine according to  claim 11  additionally comprising at least one stay extending from a portion of the engine body other than the intake port to the air chamber.  
     
     
         19 . The engine according to  claim 18  wherein the portion of the engine body comprises a cam chamber cover.  
     
     
         20 . The engine according to  claim 11 , wherein the insulating member is elastic.  
     
     
         21 . A watercraft comprising a hull defining an engine compartment, an internal combustion engine disposed in the engine compartment, the engine including an engine body defining a combustion chamber, an air induction system configured to guide air into the combustion chamber, the air induction system comprising an intake air chamber configured to guide intake air toward the combustion chamber, an electrical component disposed in the air chamber, and means for insulating the electrical component from engine produced vibrations.  
     
     
         22 . The watercraft according to  claim 21 , wherein the electrical component is a fuel injector.  
     
     
         23 . The watercraft according to  claim 21  additionally comprising a throttle body connected to the air chamber, the electrical component being connected to the throttle body.  
     
     
         24 . A small watercraft comprising a hull defining an engine compartment, an internal combustion engine disposed in the engine compartment, the engine including an engine body defining a combustion chamber, an air induction system configured to guide air into the combustion chamber, the air induction system comprising and intake air chamber configured to guide intake air toward the combustion chamber, an electrical component disposed in the air chamber, and means for insulating the electrical component from engine produced heat.  
     
     
         25 . The watercraft according to  claim 24 , wherein the electrical component is a fuel injector.  
     
     
         26 . The watercraft according to  claim 24  additionally comprising a throttle body connected to the air chamber, the electrical component being connected to the throttle body.