The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 27, 1978
Filed:
Oct. 04, 1976
Rajamouli Gunda, Rochester, MI (US);
The Bendix Corporation, Southfield, MI (US);
Abstract
A frequency modulated control circuit for an electronic fuel injection system to control the pulse-type injection of fuel at a single point of the fuel intake of an internal combustion engine in accordance with the derived mass air flow rate into the engine comprising a pressure sensor for sensing the manifold pressure of the internal combustion engine, and an engine speed sensor, both of which generate an analog signal which are multiplied by a multiplier circuit to provide a signal representative of the mass air flow to the engine. The multiplier circuit includes a separate control input for varying the output signal level of the multiplier circuit by a preselected factor determined by the final output of the control circuit. The output of the multiplier circuit is fed to a voltage controlled oscillator to produce an output signal taking the form of a pulse train, the frequency of which varies with the amplitude of the mass air flow signal. The output of the voltage controlled oscillator is fed to a pulse generator which generates a fixed on-time pulse for each pulse in the pulse train being fed from the voltage controlled oscillator. The output of the pulse generator is sensed by a duty cycle switch which senses when the output frequency of the voltage controlled oscillator results in a high duty cycle for the output pulses. In this high duty cycle situation, the output analog signal of the multiplier is reduced by a preselected fraction. The duty cycle switch also generates an output signal which varies the duration of the pulse output from the pulse generator as a reciprocal of the variation being applied to the multiplier from the duty cycle switch or enable a secondary injector. The system also includes a temperature sensor and coolant temperature circuit which generates an analog voltage signal which varies as a function of the engine coolant temperature. The temperature analog signal, designated V.sub.H.sbsb.2.sub.O, is fed to a cold start circuit to control the output pulse width from the cold start circuit.