Abstract: A hydraulic system for use in engines having reciprocating pistons and rotary piston rods wherein hydraulic fluid is supplied to each cylinder to not only lubricate the piston and cylinder but also to facilitate the movement of the piston to the top dead center position.

Abstract: A metering pulse pump for metering an additive liquid into a liquid carrier under high pressure. A high-pressure, rapidly reciprocating piston pump is provided at its outlet end with a pressure-relief valve including a spring pressure control permitting the valve to open under varying pre-set pressure differentials across the valve. A diaphragm pump having first and second chambers separated by a diaphragm is provided with one of the chambers communicating directly with the outlet of the piston pump upstream of the pressure-relief valve, liquid carrier emitted under pressure from the piston pump serving to drive the diaphragm pump in a pumping stroke, the second chamber of the diaphragm pump having inflow and outflow ports with respective check valves permitting only inflow and outflow of an additive liquid into and out of the second chamber.