Engine

Abstract

An engine comprising a cylinder housing ( 105 ) and an engine cylinder ( 110 ) at least partially housed within the housing ( 105 ). The cylinder ( 110 ) has a cylinder wall ( 118 ) extending about a cylinder axis ( 119 ), and a first cylinder end ( 120 ) provided at one axial end of the cylinder wall ( 118 ). A piston ( 115 ) is mounted for movement within the cylinder ( 110 ) in the direction of the cylinder axis ( 119 ). The piston ( 115 ), the cylinder wall ( 118 ) and the first cylinder end ( 120 ) define a cylinder chamber ( 140 ). The cylinder ( 110 ) is moveable in the direction of the cylinder axis ( 119 ) relative to the housing ( 105 ) to vary the volume of the cylinder chamber ( 140 ) for any given position of the piston ( 115 ) relative to the housing ( 105 ).

1 . An engine comprising: 
 a cylinder housing;    an engine cylinder at least partially housed within the housing;    the cylinder having a cylinder wall extending about a cylinder axis, and a first cylinder end provided at one axial end of the cylinder wall;    a piston mounted for movement within the cylinder in the direction of the cylinder axis;    the piston, the cylinder wall and the first cylinder end defining a cylinder chamber;    the cylinder being moveable in the direction of the cylinder axis relative to the housing to vary the volume of the cylinder chamber for any given position of the piston relative to the housing;    control means configured to control the position of the cylinder along the cylinder axis;    a first cam shaft;    a crank shaft;    coupling means arranged to couple rotation of the crank shaft to the first cam shaft; and    a first actuating means configured to actuate the coupling means to selectively retard and advance the rotation of the first cam shaft relative to rotation of the crank shaft.    
   
   
       2 . An engine comprising: 
 a cylinder housing;    an engine cylinder at least partially housed within the housing;    the cylinder having a cylinder wall extending about a cylinder axis, and a first cylinder end provided at one axial end of the cylinder wall;    a piston mounted for movement within the cylinder in the direction of the cylinder axis;    the piston, the cylinder wall and the first cylinder end defining a cylinder chamber; and    the cylinder being moveable in the direction of the cylinder axis relative to the housing to vary the volume of the cylinder chamber for any given position of the piston relative to the housing.    
   
   
       3 . An engine according to  claim 2 , wherein the cylinder is movable between a first position relative to the housing where the cylinder has a first ratio between a maximum volume and a minimum volume of the cylinder chamber during a predetermined movement of the piston within the cylinder; and a second position where the cylinder has a second ratio between the maximum and minimum volumes of the cylinder chamber during the same movement of the piston.  
   
   
       4 . An engine according to  claim 2  or  3 , wherein the engine comprises control means configured to control the position of the cylinder along the cylinder axis relative to the housing.  
   
   
       5 . An engine according to  claim 4 , wherein the control means comprises a hydraulic circuit for moving the cylinder relative to the housing.  
   
   
       6 . An engine according to  claim 5 , wherein the hydraulic circuit comprises a control valve arranged to selectively prevent hydraulic fluid flow through the circuit to prevent movement of the cylinder along the cylinder axis relative to the housing.  
   
   
       7 . An engine according to  claim 6 , wherein the control valve is configured to selectively allow flow of the hydraulic fluid through the hydraulic circuit to move the cylinder along the cylinder axis relative to the housing to thereby increase or decrease the effective volume of the cylinder chamber, as desired, for any given position of the piston relative to the housing.  
   
   
       8 . An engine according to  claim 7 , comprising a plurality of cylinder/piston combinations mounted in the housing, with the position of each cylinder relative to the housing, being controlled by the hydraulic circuit.  
   
   
       9 . An engine according to  claim 4  comprising: 
 a first cam shaft; a crank shaft; coupling means arranged to couple rotation of the crank shaft to the first cam shaft; and a first actuating means configured to actuate the coupling means to selectively retard and advance the rotation of the first cam shaft relative to rotation of the crank shaft.    
   
   
       10 . An engine according to  claim 9 , wherein the control means are configured to move each cylinder relative to the housing on activation of the first actuating means.  
   
   
       11 . An engine according to  claim 9 , wherein the coupling means comprises a timing belt.  
   
   
       12 . An engine according to  claim 9 , wherein the first actuating means comprises at least one solenoid.  
   
   
       13 . An engine according to  claim 9 , further comprising: 
 a second cam shaft; and a second actuating means, wherein the coupling means is arranged to couple rotation of the crank shaft to the second cam shaft, and the second actuating means is configured to actuate the coupling means to selectively retard and advance rotation of the second cam shaft relative to the first cam shaft.    
   
   
       14 . An engine according to  claim 13 , further comprising: 
 a third actuating means, wherein the coupling means is arranged to couple rotation of the crank shaft to the second cam shaft, and the third actuating means is configured to actuate the coupling means to selectively retard and advance rotation of the second cam shaft relative to rotation of the crank shaft.    
   
   
       15 . An engine, comprising: 
 a first cam shaft; a crank shaft; coupling means arranged to couple rotation of the crank shaft to the first cam shaft; and a first actuating means configured to actuate the coupling means to selectively retard and advance the rotation of the first cam shaft relative to rotation of the crank shaft.    
   
   
       16 . An engine according to  claim 15 , wherein the coupling means comprises a timing belt.  
   
   
       17 . An engine according to  claim 15 , wherein the first actuating means comprises at least one solenoid.  
   
   
       18 . An engine according to  claim 15 , further comprising: 
 a second cam shaft; and a second actuating means, wherein the coupling means is arranged to couple rotation of the crank shaft to the second cam shaft, and the second actuating means is configured to actuate the coupling means to selectively retard and advance rotation of the second cam shaft relative to the first cam shaft.    
   
   
       19 . An engine according to  claim 18 , further comprising: 
 a third actuating means, wherein the coupling means is arranged to couple rotation of the crank shaft to the second cam shaft, and the third actuating means is configured to actuate the coupling means to selectively retard and advance rotation of the second cam shaft relative to rotation of the crank shaft.