Fuel-optimizing electronic control circuit for a fuel-injected marine engine or the like

Claim 1

A fuel control system for providing maximum fuel economy over a wide range of engine throttle conditions of an internal combustion marine engine, comprising: storage means for storing a fuel control signal whose magnitude is related to the operating r.p.m. of the internal combustion engine; means for reducing the magnitude of said stored fuel control signal in response to achieving a steady state of the operating r.p.m. of the internal combustion engine; fuel control means for controlling fuel flow to the internal combustion engine in response to the instantaneous reducing magnitude of said stored fuel control signal whereby the fuel/air ratio of the internal combustion engine is reduced as the magnitude of said stored fuel control signal is reduced; first comparative means for comparing a steady state r.p.m.-representative signal representing said steady state operating r.p.m. of the internal combustion engine with an actual operating r.p.m. signal representing the reducing actual operating r.p.m. of the internal combustion engine; and means responsive to said first comparative means for causing an increase in said magnitude of said stored fuel control signal in said storage means when said actual operating-r.p.m. signal falls below said steady state r.p.m. signal by a predetermined amount.

Claim 8

A method of increasing fuel efficiency in the operation of a marine internal combustion engine, for a given one of a plurality of engine-throttle settings, the method comprising the steps of: allowing the operating r.p.m. of the internal combustion engine to increase to a steady state value; storing an r.p.m.-signal value corresponding to said steady state value; fuel-leaning the air/fuel ratio of the internal combustion engine, whereby engine r.p.m. reduces from said steady-state value; monitoring a decrease in said operating r.p.m. of the internal combustion engine with respect to said stored r.p.m.-signal value; and fuel-enriching said air/fuel ratio by a predetermined amount when said operating r.p.m. of the internal combustion engine has been reduced with respect to said stored r.p.m.-signal value by a predetermined amount.

Claim 9

A method of increasing fuel efficiency in the operation of a marine internal combustion engine, for a given one of a plurality of engine-throttle settings, the method comprising the steps of: allowing the operating r.p.m. of the internal combustion engine to increase to a steady state value; storing an r.p.m.-signal value corresponding to said steady state value; fuel-leaning the air/fuel ratio of the internal combustion engine, whereby engine r.p.m. reduces from said steady-state value; monitoring a decrease in said operating r.p.m. of the internal combustion engine with respect to said stored r.p.m.-signal value; and fuel-enriching said air/fuel ratio by a predetermined amount when said operating r.p.m. of the internal combustion engine has been reduced with respect to said stored r.p.m.-signal value by a predetermined amount.