Method and apparatus for controlling the fuel supply of an internal combustion engine

Claim 1

A method for controlling the fuel injection system of an internal combustion engine, comprising the steps of providing sensor means for generating signals related to at least one of the operational variables in the group comprising: engine speed (rpm), air flow rate through the induction tube of the engine, air pressure in the induction tube, and engine temperature; providing means for processing the signals from said sensor means to generate fuel injection control pulses for said fuel injection system to thereby determine the fuel quantity fed to said engine; sensing engine speed; determining whether the engine speed is higher or lower than a predetermined speed: sensing the position of an engine throttle valve corresponding to the throttle valve opening; determining whether the throttle valve opening is larger or smaller than a predetermined opening; an engine overrunning condition (negative output torque) when the engine speed is higher than said predetermined speed and simultaneously the throttle valve opening is smaller than said predetermined opening; interrupting the fuel injection for said engine when said engine is operating in the overrunning condition; and increasing the pulse length of said fuel injection control pulses for a predetermined time after the termination of said overrunning condition, to increase the fuel quantity fed to said engine, over the fuel quantity normally supplied, for said predetermined period of time after the termination of said overrunning condition.

Claim 2

A method for controlling the fuel injection system of an internal combustion engine, comprising the steps of providing sensor means for generating signals related to at least one of the operational variables in the group comprising: engine speed (rpm), air flow rate through the induction tube of the engine, air pressure in the induction tube, and engine temperature; providing means for processing the signals from said sensor means to generate fuel injection control pulses for said fuel injection system to thereby determine the fuel quantity fed to said engine; sensing engine speed; determining whether the engine speed is higher or lower than a predetermined speed: sensing the position of an engine throttle valve corresponding to the throttle valve opening; determining whether the throttle valve opening is larger or smaller than a predetermined opening; an engine overrunning condition (negative output torque) when the engine speed is higher than said predetermined speed and simultaneously the throttle valve opening is smaller than said predetermined opening; interrupting the fuel injection for said engine when said engine is operating in the overrunning condition; and increasing the pulse length of said fuel injection control pulses for a predetermined time after the termination of said overrunning condition, to increase the fuel quantity fed to said engine, over the fuel quantity normally supplied, for said predetermined period of time after the termination of said overrunning condition.

Claim 3

An apparatus for controlling the fuel injection system of an internal combustion engine, said fuel injection system including: sensor means for generating signals related to at least one operating variable of said engine; pulse generating means for generating fuel injection control pulses on the basis of said signals from said sensor means; fuel metering means for injecting a metered quantity of fuel to said engine proportional to said fuel injection control pulses from said pulse generating means; transducer means for generating a signal to indicate the condition of engine overrunning (negative output torque), which includes timing signal generating means for generating timing output signals, a tacho-generator connected to said engine for generating output signals indicating engine speed, a comparator for comparing the output signals from said timing signal generating means with the output signals from said tacho-generator, a throttle valve position indicator and circuit means for indicating the simultaneous condition of the output of said comparator and the output from said throttle valve position indicator, thereby signaling said condition of engine overrunning; fuel shut-off means for inhibiting the injection of fuel to said engine during said condition of engine overrunning; electronic fuel boosting circuit means connected to said fuel injection system for providing a fuel boosting control signal for a predetermined period of time subsequent to termination of said condition of engine overrunning; and pulse correcting circuit means, disposed intermediate said pulse generating means and said fuel metering means and connected to receive said fuel boosting control signal, for increasing the pulse length of said fuel injection control pulses on the basis of said fuel boosting control signal, to provide an increased quantity of fuel to the engine during said predetermined period of time, to thus insure rapid re-heating of the engine subsequent to termination of said condition of engine overruning.

Claim 4

An apparatus for controlling the fuel injection system of an internal combustion engine, said fuel injection system including: sensor means for generating signals related to at least one operating variable of said engine; pulse generating means for generating fuel injection control pulses on the basis of said signals from said sensor means; fuel metering means for injecting a metered quantity of fuel to said engine proportional to said fuel injection control pulses from said pulse generating means; transducer means for generating a signal to indicate the condition of engine overrunning (negative output torque), which includes timing signal generating means for generating timing output signals, a tacho-generator connected to said engine for generating output signals indicating engine speed, a comparator for comparing the output signals from said timing signal generating means with the output signals from said tacho-generator, a throttle valve position indicator and circuit means for indicating the simultaneous condition of the output of said comparator and the output from said throttle valve position indicator, thereby signaling said condition of engine overrunning; fuel shut-off means for inhibiting the injection of fuel to said engine during said condition of engine overrunning; electronic fuel boosting circuit means connected to said fuel injection system for providing a fuel boosting control signal for a predetermined period of time subsequent to termination of said condition of engine overrunning; and pulse correcting circuit means, disposed intermediate said pulse generating means and said fuel metering means and connected to receive said fuel boosting control signal, for increasing the pulse length of said fuel injection control pulses on the basis of said fuel boosting control signal, to provide an increased quantity of fuel to the engine during said predetermined period of time, to thus insure rapid re-heating of the engine subsequent to termination of said condition of engine overruning.