Starting-enrichment control for a fuel-injected engine

Claim 1

In a multi-cylinder internal-combustion engine having a starter-operated fuel pump and an electronically controlled fuel-injection system wherein a pulse generator provides fuel-injection control pulses of time duration proportioned to desired throttle setting among other factors, the pulses each having a duration which is at all times a small fraction of the duration of a full cycle of operation of a given cylinder of the engine, and wherein engine-cranking starter-operated means are operative upon starting the engine to temporarily enrich the fuel supplied to the engine by temporarily providing fuel-injection control pulses of greater time duration than that which applies for maximum throttle setting, the improvement in which the starter-operated means includes: (1) pressure-sensitive means which is responsive to pumped fuel pressure to delay generation of any greater-duration pulses until sensed achievement of a predetermined adequate level of fuel-injection pressure, whereby engine-priming is initiated only with adequate fuel pressure, (2) means limiting engine-priming to a single priming pulse of relatively great duration for each cylinder for any given continuous period of engine cranking, (3) temperature-sensitive means which is responsive to engine temperature to determine the duration of said single priming pulse as an inverse function of sensed engine temperature, and (4) time-delay means responsive to an engine-priming operation of said pressure-sensitive means to determine a further delay period in which the generation of any greater-duration pulse is materially suppressed, whereby the danger of engine-flooding is avoided or substantially reduced for attempted starting within said further delay period.