Variable compression ratio device for internal combustion engine

#The present invention relates generally to the field of internal combustion engines, and more specifically to engines operated under homogenous charge compression ignition principles and piston arrangements therefor.

#An internal combustion engine combusts a fuel and air mixture within one or more combustion cylinders, and converts the energy from the combustion process into mechanical output energy. It has been known for many years to use spark ignition and combustion ignition concepts in internal combustion engines. In spark ignition engines, a mixture of fuel and air is provided to a combustion cylinder and compressed. A spark plug initiates combustion through the creation of an open spark sufficient to ignite the air and fuel mixture in the cylinder. Both two and four stroke operating sequences are known.

#In a direct injection combustion ignition engine, such as a diesel engine, it also is common to use both two and four stroke operating sequences. Turbochargers are often used to supply a charge of air to the combustion cylinders at higher pressure and density than existing ambient conditions. On an upward stroke of the cylinder, the air intake ports are closed and the air is highly compressed. At the desired level of compression, fuel is sprayed into the cylinder by a fuel injector. The fuel ignites immediately, as a result of the heat and pressure inside the cylinder. The pressure created by the combustion of the fuel drives the piston downward in the power stroke of the engine.

#FIG. 1 is a sectional, partially fragmentary view of an embodiment of an internal combustion engine of the present invention within a work machine;

#FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1; and

#FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2.

#Referring now to the drawings, and more particularly to FIGS. 1 and 3, there is shown an embodiment of an internal combustion engine 10 of the present invention which is incorporated within a work machine such as an on-road vehicle, off-road vehicle, tractor, excavator or the like. An engine 10 according to the present invention is also suited to engines intended primarily for stationary single-speed operation installations, such as, for example, powering a generator. The work machine includes a frame 12 that carries internal combustion engine 10, as designated schematically by phantom line 14.

#Engine 10 includes an engine block 16 that defines one or more combustion cylinders 18, and typically defines a plurality of combustion cylinders 18, which in preferred embodiments may be four, six, eight, twelve, sixteen or twenty combustion cylinders 18. At an end 20 of combustion cylinders 18, a head 22 is provided on block 16 above all cylinders 18.

#While in most applications of the present invention a plurality of cylinders 18 are provided in engine 10, for purposes of simplicity, only one such cylinder 18 is shown in the drawings. A primary piston 24 is reciprocally disposed within combustion cylinder 18, and movable between a top dead center position adjacent head 22 (as shown in FIG. 1) and a bottom dead center position at an opposing end of combustion cylinder 18. Primary piston 24 includes a rod 26 coupled therewith on a side opposite from head 22.