System for producing a pulse signal for controlling an internal combustion engine
First Claim
1. A system for normally producing a first pulse signal for controlling an automotive internal combustion engine in response to engine operating parameters, such as engine crankshaft reference angle position pulses, air intake volume and engine temperature, and for producing a second pulse signal for controlling the engine in the event of a failure of circuitry responsive to the parameters, comprising:
- (A) a digital computer responsive to the parameters for controlling the derivation of engine control pulses in accordance with the parameters, said computer including;
(a) a first output circuit responsive to the reference angle pulses for deriving engine control pulses, and(b) a second output circuit for deriving a marker pulse signal having a regular pulse interval; and
(B) a circuit for producing a dummy control signal in response to a computer malfunction, including;
(a) a first retriggerable monostable multivibrator responsive to the marker pulse signal derived by said second output circuit, said first retriggerable monostable multivibrator deriving a first switching signal in response to the pulse interval of the pulse signal produced by the second output circuit exceeding a first predetermined length of time;
(b) a monostable multivibrator responsive to the reference angle pulse signal for deriving further control pulses synchronized with the reference angle position pulses; and
(c) switching means having an output terminal and an input connected to be controlled by said first retriggerable monostable multivibrator for normally coupling the control pulses derived by said first output circuit to the output terminal and for coupling the further pulses derived by said monostable multivibrator to the output terminal while said first switching signal is derived.
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Accused Products
Abstract
In a system for producing a pulse signal for controlling an internal combustion engine, an engine control pulse signal is calculated by a digital computer during normal operation. If a failure or a malfunction of the digital computer is detected, the engine control pulse signal is replaced with a dummy signal produced by an auxiliary pulse generator.
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Citations
16 Claims
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1. A system for normally producing a first pulse signal for controlling an automotive internal combustion engine in response to engine operating parameters, such as engine crankshaft reference angle position pulses, air intake volume and engine temperature, and for producing a second pulse signal for controlling the engine in the event of a failure of circuitry responsive to the parameters, comprising:
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(A) a digital computer responsive to the parameters for controlling the derivation of engine control pulses in accordance with the parameters, said computer including; (a) a first output circuit responsive to the reference angle pulses for deriving engine control pulses, and (b) a second output circuit for deriving a marker pulse signal having a regular pulse interval; and (B) a circuit for producing a dummy control signal in response to a computer malfunction, including; (a) a first retriggerable monostable multivibrator responsive to the marker pulse signal derived by said second output circuit, said first retriggerable monostable multivibrator deriving a first switching signal in response to the pulse interval of the pulse signal produced by the second output circuit exceeding a first predetermined length of time; (b) a monostable multivibrator responsive to the reference angle pulse signal for deriving further control pulses synchronized with the reference angle position pulses; and (c) switching means having an output terminal and an input connected to be controlled by said first retriggerable monostable multivibrator for normally coupling the control pulses derived by said first output circuit to the output terminal and for coupling the further pulses derived by said monostable multivibrator to the output terminal while said first switching signal is derived. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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- 8. In an apparatus for controlling timing of fuel injection valves or ignition of an automotive internal combustion engine in response to engine performance parameters, such as air intake volume engine temperature and crankshaft rotation angle, the apparatus comprising a digital computer responsive to the parameters for deriving a first pulsed engine control signal with pulses having widths dependent upon the values of the parameters and an occurrence time in synchronism with the crankshaft passing predetermined reference angles, a triggered monostable pulse generator responsive to crankshaft rotation for deriving a second pulsed engine control signal with pulses having an occurrence time in synchronism with the crankshaft passing the predetermined reference angles, means for sensing abnormal operation of the computer, and switch means responsive to the sensing means for coupling the first signal to a means for controlling the timing to the exclusion of the second signal while the computer operates normally and for coupling the second signal to the means for controlling the timing to the exclusion of the first signal while the computer operates abnormally.
Specification