Multiple cylinder engine

An internal combustion engine comprising:

• a first piston reciprocatingly disposed in a first cylinder;
• a combustion chamber fluidly coupled with the first cylinder;
• an ignition source at least partially disposed within the combustion chamber;
• an intake valve providing selective fluid communication between an intake system and the combustion chamber;
• an exhaust valve providing selective fluid communication between an exhaust system and the combustion chamber;
• a second piston reciprocatingly disposed within a second cylinder, wherein the second piston includes a reciprocating mass configured to at least partially counterbalance reciprocating movement of the first piston, and wherein the second cylinder includes a vent allowing air to enter and exit the second cylinder during reciprocation of the second piston, and wherein the second piston is a non-fired piston that does not effectuate fluid transfer between the second cylinder and the combustion chamber;
• and
• a crankshaft coupled with the first piston and the second piston for rotational motion associated with reciprocating movement of the first piston and the second piston.

An internal combustion engine comprising:

• a first piston reciprocatingly disposed in a first cylinder;
• a combustion chamber fluidly coupled with the first cylinder;
• an ignition source at least partially disposed within the combustion chamber;
• an intake valve providing selective fluid communication between an intake system and the combustion chamber;
• an exhaust valve providing selective fluid communication between an exhaust system and the combustion chamber;
• a second piston reciprocatingly disposed within a second cylinder, wherein the second piston includes a reciprocating mass configured to tune a vibrational characteristic of the internal combustion engine, and wherein the second cylinder includes a vent allowing air to enter and exit the second cylinder during reciprocation of the second piston;
• and
• a crankshaft coupled with the first piston via a first crank journal for rotational motion associated with reciprocating movement of the first piston, and coupled with the second piston via a cam for reciprocating motion of the second piston in response to rotation motion of the crankshaft.