Pre-Oiling System during Cold-Start of SI Engine

Cold-startability of a modern SI-engine is no longer a problem, thanks to advanced fuel injection and ignition systems as well as engine pre-heaters. However, the engine lubrication does not work as required before the oil pressure has been built up at even the farmost end of the lube system. In subzero conditions down to -30 °C this means the engine may run 30 … 70 seconds after turning the ignition key without the camshaft and valve mechanism receiving sufficient lubrication /1/. Daily cold-starts in very low ambient temperatures may be critical to the engine life, especially if the lubricant has not been chosen carefully.

By using a pre-oiling device generating pressure in the main oil gallery before starting, the lubrication delay can be significantly shortened if the lubricant is a mineral oil. However, the pre-oiling also needs pre-heating