Fuel control system having an auxiliary circuit for correcting the signals generated by the pressure sensor during transient operating conditions
AssigneeThe Bendix Corporation
InventorLael Brent Taplin
Life of this patent
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Abstract
A fuel control system having an auxiliary circuit for correcting the signals generated by a pressure sensor under transient operating conditions is disclosed. The circuit generates a pressure correction signal directly proportional to the first time derivative of the intake manifold pressure and inversely proportional to rotational speed of the engine which is added to the signal generated by the pressure sensor. The added signals are utilized by the electronic control unit for computing the fuel requirements of the engine to maintain a constant fuel/air ratio during steady state and transient operating conditions.
Claims23
An electronic fuel injection system for an internal combustion engine comprising:
- engine sensor means for generating signals indicative of engine operating conditions, said sensor means including pressure sensor means for generating a pressure signal indicative of engine air intake manifold pressure, and speed sensor means for generating a speed signal indicative of engine operating speed;
- pressure signal correction circuit means for generating a corrected pressure signal having a value equal to the sum of said pressure signal and a correction signal generated in response to said pressure signal and said speed signal, when the pressure signal is changing and indicative of a transient condition;
- electronic control unit means for generating electrical signals indicative of engine fuel requirements in response to signals generated by said engine sensors, including said speed signal and said corrected pressure signal;
- and
- fuel delivery means for delivering fuel in response to the signals generated by said electronic control unit means.
In combination with an electronic fuel injection system for an internal combustion engine, said electronic fuel injection system having engine sensors generating signals indicative of engine operating conditions, including pressure sensor means generating pressure signals indicative of engine air intake manifold pressure and speed sensor means generating speed signals indicative of engine speed, and an electronic control unit generating electrical signals indicative of engine fuel requirements, and at least one injector means for delivering fuel in response to the electrical signals generated by the electronic control unit, a pressure signal correction circuit means electrically disposed between said pressure sensor and said electronic control unit for generating corrected pressure signals in response to said pressure signals and said speed signals, said corrected pressure signal being indicative of the actual engine air flow during steady state and transient operating conditions.
In an electronic fuel injection equipped internal combustion engine system having an internal combustion engine, engine sensors generating signals indicative of the engine's operating conditions, including pressure sensor means generating pressure signals indicative of the pressure in the engine's air intake manifold and speed sensor means generating speed signals indicative of the rotational speed of the engine, an electronic control unit responsive to at least said pressure and said speed signals for generating electrical signals indicative of the engine's fuel requirements, and at least one injector means for injecting fuel into the engine in response to the electrical signals generated by the electronic control unit, an improvement for correcting the pressure signals generated by the pressure sensor means during transient modes of operation comprising:
- means responsive to the signals generated by the pressure sensor means and the speed sensor means for generating pressure correction signals to compensate for the compressibility of air intake manifold when the engine is in a transient mode of operation;
- and
- means for summing said pressure correction signals to said pressure signals to generate a corrected pressure signal;
- wherein said electronic control unit generates said electrical signals in response to said corrected pressure signal.
A circuit for use in combination with a pressure sensor and an internal combustion engine having an air intake manifold and electronic fuel control to correct the signals generated by the pressure sensor during transient operating conditions, wherein said pressure sensor generates pressure signals indicative of the pressure in the engine's air intake manifold and said engine has at least one other sensor generating a speed signal indicative of the rotational speed of the engine comprising:
- differentiator circuit means receiving said pressure signals and said speed signals for generating pressure correction signals having a value proportional to the first time derivative of the pressure in the intake manifold and inversely proportional to the rotational speed of the engine;
- and
- means for summing said pressure correction signal to said pressure signal to generate a corrected pressure signal.
In combination with a utilization device having a fluid intake manifold and a pressure sensor generating a signal indicative of the fluid pressure in the intake manifold, a circuit for correcting the pressure signal generated by a pressure sensor for the compressibility of the fluid flowing in the intake manifold of the utilization device comprising:
- sensor means generating speed signals indicative of the speed of fluid flow through the utilization device;
- circuit means receiving said pressure signals and said speed signals for generating a pressure correction signal having a value proportional to the first time derivative of the pressure signal and inversely proportional to the speed signal;
- and
- means for adding said pressure correction signal to said pressure signal.
A method for correcting the pressure signals generated by a pressure sensor monitoring the pressure in the intake manifold of an internal combustion engine for the compressibility of the air during transient modes of operation comprising the steps of:
- detecting the pressure in the engine's intake manifold with a pressure sensor to generate pressure signals;
- differentiating the pressure signals generated by the pressure sensor to generate a differentiated signal having a value proportional to the first time derivative of pressure in the intake manifold;
- detecting the rotational speed of the engine to generate a speed signal;
- dividing the differentiated signal by said speed signal to generate a correcton signal having a value proportional to the first time derivative of the pressure and inversely proportional to the rotational speed of the engine;
- and
- adding said correction signal to pressure signal to generate a pressure signal compensated for the compressibility of the air.
Dependencies are inferred from the claim text.