Abstract: Torque multiplier engines, and associated methods and systems, are disclosed herein. An internal combustion engine in accordance with a particular embodiment can include a connecting rod operably coupling a pair of opposing pistons. The engine can further include a first bearing coupled to the connecting rod and positioned to engage a first cam groove of an inner cam drum. A second bearing coupled to the connecting rod can be positioned to engage a second cam groove on an outer cam drum. The first and second bearings can translate linear motion of the opposing pistons to rotation of the cam drums.

Abstract: The present disclosure is directed to various embodiments of systems and methods for cooling a combustion chamber of an engine. One method includes introducing fuel into the combustion chamber of an engine having an energy transfer device that moves through an intake stroke, a compression stroke, a power stroke, and an exhaust stroke. The method further includes monitoring a temperature of the combustion chamber. When the temperature reaches a predetermined value, the method also includes introducing coolant into the combustion chamber only during at least one of the power stroke and the exhaust stroke of the energy transfer device.

Abstract: Embodiments of injectors configured for adaptively injecting multiple different fuels and coolants into a combustion chamber, and for igniting the different fuels, are disclosed herein. An injector according to one embodiment includes a body having a first end portion and a second end portion. The injector further includes a first flow channel extending through the body, and a second flow channel extending through the body that is separate from the first flow channel and electrically isolated from the first flow channel. The first flow channel is configured to receive a first fuel, and the second flow channel is configured to receive at least one of a second fuel and a coolant. The injector further comprises a valve carried by the body that is movable between a closed position and an open position to introduce at least one of the second fuel and the coolant into a combustion chamber.

Abstract: An internal combustion engine is described in which the piston movement is parallel to the drive shaft. The engine cylinders are arranged in opposed pairs and the piston rods directly coupled so that the power stroke in one cylinder can assist with the compression stroke in the associated cylinder. The coupled or common piston rods have attached thereto a carriage that engages in a cam groove in the drive shaft. The drive shaft cam groove receives the force of the carriage as it is propelled by the pistons and the resulting torque causes a rotation of the drive shaft. The cylinders include a precompression chamber that assists in the exchange of combustion products with air. The internal combustion engine does not require special cooling and does not require a starter motor.