×

Air-fuel ratio feedback type fuel injection system

  • US 3,895,611 A
  • Filed: 10/12/1973
  • Issued: 07/22/1975
  • Est. Priority Date: 10/17/1972
  • Status: Expired due to Term
First Claim
Patent Images

1. An air-fuel ratio feedback type fuel injection system having electromagnetic valve means connected to a constant pressure fuel line to inject the fuel into an internal combustion engine mounting the fuel injection system and a computing unit connected through an electromagnetic valve actuating circuit to the electromagnetic valve means for generating an injection pulse signal to determine the opening duration of the electromagnetic valve means thereby to control the quantity of said fuel to suitable various operating conditions of the internal combustion engine, comprising:

  • an oxygen concentration detector mounted in an exhaust pipe of said engine for detecting the concentration of oxygen contained in the exhaust gases of said engine, an air-fuel ratio discriminating circuit means connected to said oxygen concentration detector for comparing an output signal of said detector with a predetermined value to generate an output signal, a sampling signal generating circuit means for generating a sampling signal having a predetermined frequency, an addition and subtraction command circuit means connected to said sampling signal generating circuit means and said air-fuel ratio discriminating circuit means for generating an output command signal in accordance with the output signal of said air-fuel ratio discriminating circuit each time said sampling signal is applied thereto, a reversible counter connected to said addition and subtraction command circuit means to perform the operation of addition or subtraction on the count thereof in accordance with said output command signal of said addition and subtraction command circuit means for generating a correction signal, and valve opening duration correcting means connected to said reversible counter and further to said computer unit for controlling the opening duration of said electromagnetic valve means in accordance with said correction signal of said reversible counter in cooperation with said computing unit to reverse the output signal of said air-fuel ratio discrimination circuit means by changing the quantity of said fuel through said valve means.

View all claims
  • 0 Assignments
Timeline View
Assignment View
    ×
    ×