A pump element (1), such as a piston pump element, for conveying lubricant. The pump element (1) can be fitted in a pump unit. The pump element (1) has a first housing portion (2) and a second housing portion (4). The first housing portion (2) moves into engagement with the pump unit. The second housing portion (4) receives lubricant through a lubricant inlet (32) and conveys the received lubricant to a lubricant outlet (14, 46). The first housing portion (2) and the second housing portion (4) are in the form of separate elements.

A two-stroke engine comprises a first oiling system and a second oiling system. The first oiling system includes a low-pressure pump that distributes oil from a first oil tank to the two-stroke engine. The second oiling system includes a pump mechanically coupled to a crankshaft of the two-stroke engine, wherein the pump distributes oil from a second oil tank to an accessory at a pressure greater than the first oil pressure, wherein oil distributed to the accessory is returned to the second oil tank.

A two-stroke engine comprises a first oiling system and a second oiling system. The first oiling system includes a low-pressure pump that distributes oil from a first oil tank to the two-stroke engine. The second oiling system includes a pump mechanically coupled to a crankshaft of the two-stroke engine, wherein the pump distributes oil from a second oil tank to an accessory at a pressure greater than the first oil pressure, wherein oil distributed to the accessory is returned to the second oil tank.

A lubricant dosing device for a gaseous fuel delivery system of an internal combustion engine, in particular a hydrogen engine, includes a body having therein a pumping bore extending along a pumping axis and defining, at an end, a pumping chamber which volume is varied by a piston reciprocating in the pumping bore. An inlet valve assembly is arranged in an inlet section. An outlet section includes an outlet valve assembly to control the discharge of pressurized lubricant fluid from the pumping chamber. The outlet valve assembly is configured as a check-valve with an outlet valve seat and an outlet valve member downstream thereof. The outlet valve member includes a sealing surface adapted to cooperate with the outlet valve seat the sealing surface being formed of or coated with a resilient polymer.