Patent Document ID: 4655188
Application ID: 06768480
Patent Flag: 1

Claim One:
1. An apparatus for learning control of the air-fuel ratio of an air-fuel mixture in an electronically controlled fuel injection type internal combustion engine, wherein comprises engine-driving state detecting means including at least first detecting means 21 for detecting a flow quantity Q of intake air in the engine, second detecting means 31 for detecting a rotation speed N of the engine and third detecting means 26 for detecting an actual air-fuel ratio .lambda. of the air-fuel mixture sucked in the engine by detecting a concentration of an exhaust component, fuel injection means 25 for injecting and supplying a fuel to the engine in an on-off manner in response to a driving pulse signal, basic fuel injection quantity operating means 201 for operating a basic injection quantity Tp of the fuel to be supplied to the engine based on the flow quantity Q of intake air in the engine, which is put out by said first detecting means 21, and the engine rotation speed N put out by said second detecting means 31, reloadable memory means 205 in which a learning correction coefficient .alpha.o for correcting said basic fuel injection quantity Tp is stored in advance for each of engine-driving state areas of a predetermined range, learning correction coefficient retrieval means 206 for retrieving the learning correction coefficient .alpha.o from said memory means 205 according to the actually detected driving state of the engine, feedback correction coefficient setting means 202 for increasing, for decreasing, and for setting a feedback correction coefficient .alpha. for correcting said basis fuel injection quantity Tp so that the actual air-fuel ratio .lambda. put out by said third detecting means 26 is brought close to a preset aimed air-fuel ratio .lambda.t, learning correction coefficient renewal means 207 for setting a new learning correction coefficient .alpha.o(new), which is operated based on the feedback correction coefficient .alpha. set by said feedback correction coefficient setting means 202 and the learning correction coefficient .alpha.o retrieved by said learning correction coefficient retrieval means 206 according to the detected driving state of the engine, as the learning correction coefficient .alpha.o of the corresponding engine-driving state area of said memory means, learning advance degree judging means 209 for judging a degree of the advance of learning in each engine-driving state area by a frequency C of renewal of the learning correction by said correction renewal means 210 for estimating and operating the learning correction coefficient .alpha.o of the engine-driving state area, in which the degree of the advance of learning is judged as being small by said learning advance degree judging means 209, with a certain relation to the learning correction coefficient .alpha.o of the engine-driving state area in which the learning advance degree is judged as being large and setting said estimated learning correction coefficient .alpha.s as the learning correction coefficient .alpha.o of the corresponding engine-driving state area of said memory means 205, fuel injection quantity operating means 203 for correcting the basic fuel injection quantity Tp based on retrieval and on renewed learning correction coefficients .alpha.o and further correcting the basic fuel injection quantity Tp based on the feedback correction coefficient .alpha. set by said feedback correction coefficient setting means 202, and operating a fuel injection quantity Ti based on said corrected value, and driving pulse signal output means 204 for putting out the driving pulse signal corresponding to the fuel injection quantity Ti to said fuel injection means 25.