Abstract: An internal combustion engine having six in-line piston and cylinder assemblies providing a center pair, an intermediate pair and an outer pair, each pair having crankshaft connected pistons mounted in cylinders through simultaneous repetitive strokes four of which together constitute simultaneous repetitive cycles including a drive event injectors selectively (1) in a (Mode 1) to inject fuel in both cylinders and (2) in a (Mode 2) to inject fuel in only one cylinder, the cylinders of the center pair being intercommunicated by a passage. The effect of skipping an injection in (Mode 2) in the center pair is a pair of shared power drive events and in the other pairs the effect in one of the cylinders is a directly fired power drive shaft and the effect in the other cylinder is deactivation and a method of operating the engine in a vehicle.

Abstract: One non-limiting object of the present invention is to provide modifications to conventional in line 6 cylinder engines capable of increasing their efficiency in operation. This includes modifying the central two adjacent piston and cylinder assemblies of the engines. The modifications involve (1) changing the camshaft so that the central two adjacent piston and cylinder assemblies have their four stroke cycles in phase rather than 180° out of phase, (2) providing a communicating passage between the combustion chambers of the central two piston and cylinder assemblies and (3) modifying either the hardware or programming for the control of the fuel injectors of the central two piston and cylinder assemblies so that they can be selectively controlled not to inject fuel during the operation cycle thereof.