US 5,983,877 A · Apparatus and a method for adjusting the air fuel ratio of an internal combustion engine

Abstract

The present invention overcomes these problems by providing an oxygen sensor located in the exhaust stream of an internal combustion engine, a load sensing device which generates a signal indicative of an internal combustion engine load, a central processing unit which calculates a running average of the oxygen content in the exhaust stream indicated by the oxygen sensor and a fuel injection device which supplies fuel to the combustion air in response to the central processing unit. The central processing unit uses the running average of the oxygen content in the exhaust stream, in lieu of the instantaneous oxygen content, to modify the fuel equation for determining the proper air fuel mix when transitioning from closed to open loop operation. The resulting air fuel mixture thus reflects the average oxygen value in the exhaust over a period of time. This average serves to cancel out the extreme surplus and deficiency of oxygen in the exhaust stream due to dithering.

Claims9

Dependent claims

An apparatus for adjusting the air fuel ratio of an internal combustion engine, said apparatus comprising:

an oxygen sensor located in an exhaust stream of said internal combustion engine, said oxygen sensor generating an oxygen signal indicative of an amount of free oxygen in said exhaust stream;
a load sensing device generating a load signal indicative of said internal combustion engine load;
a speed sensing device generating a speed signal indicative of said internal combustion engine speed;
a central processing unit calculating a running average of values of said oxygen signals in a closed loop condition, said central processing unit freezing said running average to obtain a frozen running average when said internal combustion engine transitions from a closed loop to an open loop condition, said central processing unit generating a fuel signal based on said frozen running average when said load signal is indicative of said internal combustion engine transitioning from a closed loop condition to an open loop condition;
and
a fuel injection device fluidly communicating with an air steam supplying combustion air to said internal combustion engine, said fuel injection device adding fuel to said combustion air based on said fuel signal.

3 more elements

Dependencies are inferred from the claim text.

Apparatus and a method for adjusting the air fuel ratio of an internal combustion engine

Life of this patent

Apparatus and a method for adjusting the air fuel ratio of an internal combustion engine

Life of this patent

Abstract

Claims9