Induction System for a Four Cycle Engine

Abstract

A four cycle engine having at least one cylinder unit is disclosed. The engine includes a continuously variable transmission (CVT) connected to the engine on one side of the engine. An air box is also provided that is located on the same side of the engine as the CVT. The engine further includes an intake manifold operatively connected to the air box for connecting the air box to each cylinder unit and a throttle assembly operatively connected to air box and the intake manifold. The intake manifold may have a generally Y-shaped manifold having a connector leg connected to the throttle assembly and a pair of branches. One branch is operatively connected to one of the cylinder units and another branch is connected to another of the cylinder units. The connector leg is generally parallel to the axis of the crankshaft. The intake manifold may further include a baffle assembly, which directs gas flow within the intake manifold.

1 . A snowmobile comprising: 
 a frame having a longitudinal axis;    a track for propelling the snowmobile, the track being secured to the frame; and    a four cycle engine disposed on the frame, the engine having a crankshaft, a first side disposed on one side of the longitudinal axis, and a second side disposed on the other side of the longitudinal axis;    a continuously variable transmission (CVT) disposed on the first side of the engine and including a drive pulley operatively connected to the crankshaft, and a driven pulley operatively connected to the drive pulley via a drive belt, the engine driving the track via the CVT;    an air box in fluid communication with the engine;    a supercharger in fluid communication with the air box and disposed on the second side of the engine; and    a starter operatively connected to the crankshaft on the second side of the engine.    
   
   
       2 . The snowmobile of  claim 1 , wherein the engine comprises: 
 a crankcase through which the crankshaft extends, the crankshaft having a crankshaft axis being transverse to the longitudinal axis;    at least one cylinder unit connected to the crankcase, wherein each cylinder unit includes a cylinder and a cylinder head;    an intake manifold fluidly connected to the air box for fluidly connecting the air box to each of the at least one cylinder unit; and    a throttle assembly fluidly connecting the air box to the intake manifold.    
   
   
       3 . The snowmobile of  claim 2 , wherein the air box includes first and second chambers; 
 wherein the first chamber has at least one opening for fluidly connecting the first chamber to the atmosphere; and    wherein air enters the first chamber through the at least one opening, flows from the first chamber to the supercharger, flows from the supercharger to the second chamber, flows from the second chamber to the throttle body, flows from the throttle body to the air intake manifold, and flows from the air intake manifold to each of the at least one cylinder unit.    
   
   
       4 . The snowmobile of  claim 1 , wherein the starter is operatively connected to the crankshaft via a plurality of gears, the plurality of gears being disposed on the second side of the engine.  
   
   
       5 . The snowmobile of  claim 1 , further comprising a charge-air cooler for cooling air flowing from the supercharger to the engine.  
   
   
       6 . The snowmobile of  claim 2 , further comprising a charge-air cooler located forwardly of the crankshaft axis.  
   
   
       7 . The snowmobile of  claim 6 , wherein at least a portion of the charge-air cooler is located above the crankshaft axis.  
   
   
       8 . The snowmobile of  claim 2 , wherein the supercharger has a center of gravity being located rearwardly of the crankshaft axis.  
   
   
       9 . The snowmobile of  claim 8 , further comprising a charge-air cooler located forwardly of the crankshaft axis for cooling air flowing from the supercharger to the air box.  
   
   
       10 . The snowmobile of  claim 8 , wherein the starter has a center of gravity being located rearwardly of the crankshaft axis.  
   
   
       11 . The snowmobile of  claim 2 , wherein the starter has a center of gravity being located rearwardly of the crankshaft axis.  
   
   
       12 . The snowmobile of  claim 1 , wherein the air box is located on the first side of the engine.  
   
   
       13 . The snowmobile of  claim 1 , wherein the supercharger is connected to the crankcase and is operatively driven by the crankshaft.  
   
   
       14 . The snowmobile of  claim 13 , wherein the supercharger is driven by the crankshaft via gears.  
   
   
       15 . The snowmobile of  claim 2 , wherein the at least one cylinder unit includes a pair of cylinder units located on opposite sides of the crankshaft axis.  
   
   
       16 . The snowmobile of  claim 15 , wherein the pair of cylinder units are arranged at an angle with respect to each other; and 
 wherein a space is formed between the pair of cylinder units.    
   
   
       17 . The snowmobile of  claim 16 , wherein the intake manifold is located in the space between the pair of cylinder units.  
   
   
       18 . The snowmobile of  claim 16 , wherein the supercharger is located adjacent to the one of the pair of cylinder units which is located rearwardly of the crankshaft axis.  
   
   
       19 . The snowmobile of  claim 1 , wherein the supercharger includes a centrifugal blower.  
   
   
       20 . The snowmobile of  claim 2 , further comprising a fuel-injection system fluidly connected to the at least one cylinder unit.