Electronic fuel injection method and apparatus for internal combustion engine

Claim 2

A fuel injection method for an internal combustion engine, comprising following steps: - for detecting a quantity of air sucked by said engine; - detecting a revolution speed of said engine; - judging whether said engine is in a high-load state or not; - calculating a basic pulse width of a valve opening pulse for an injection valve means on the basis of the detected quantity of sucked air and the detected engine speed; - providing a first correction factor map (Fig. 5) storing a first set of predetermined correction factors corresponding to various values of the revolutional speed of said engine and various values of the to be calculated opening pulse width of said injection valve means; - providing a second correction factor map (Fig. 7) storing a second set of correction factors corresponding to various values of the revolution speed of said engine, whereby when said judging step judges that there is no high-load state a correction factor is read out corresponding to the momentarily detected revolution speed and the momentarily calculated basic valve opening pulse to thereby correct the basic valve opening pulse width calculated at that time with the read-out correction factor, while when said judging step judges that there is a high-load state a correction factor is read out corresponding to the momentarily detected revolution speed of said engine and corresponding to the basic valve opening pulse width calculated at that time and further another correction factor is read out to thereby correct the basic valve opening pulse width calculated at that time with a sum of said two read-out correction factors.

Claim 3

A method according to. Claim 1, wherein the judgment step judges whether said engine is in a highly loaded state or not on the basis of the detected revolution speed of said engine and on the basis of the calculated basic valve opening pulse width.

Claim 4

A fuel injection apparatus in an internal combustion engine according to Claim 2, wherein the judgment step is carried out on the basis of a threshold map ( F ig. 6) in which various threshold values of the basic valve opening pulse for judging the load state corresponding to the revolution speed of said engine are predetermined in advance, so as to judge said engine to be in a high-load state when said calculated basic pulse width has a value larger than a threshold value in said threshold map corresponding to the revolution speed of said engine.

Claim 5

A fuel injection apparatus in an internal combustion engine according to Claim 3, in which said threshold value varies depending on the revolution speed of said engine.

Claim 6

A fuel injection apparatus in an internal combustion engine according to Claim 3, in which having judged once that said engine is in a highly loaded state, said judgment step judges that said engine is in said high-load state unless the basic valve opening pulse width is reduced to a value lower than one of said threshold values corresponding to the revolution speed of said engine by a predetermined ratio.

Claim 7

A fuel injection apparatus for an internal combustion engine, comprising: fuel injection valve means (40) for supplying said engine with fuel; air flow rate detection means (36) for detecting a quantity of air sucked by said engine; engine revolutional speed detection means (23) for detecting a revolutional speed of said engine; load state judgement means (26) for judging whether said engine is in a highly loaded state or not; control means (26) for calculating a basic pulse width of a valve opening pulse for said injection valve means on the basis of respective output signals of said air flow detection means and said engine speed detection means; a first correction factor map (Fig. 5) storing a first set of predetermined correction factors cor=e-sponding to various values of the revolutional speed of said engine and various values of the valve opening pulse width for said injection valve means (40) to be calculated by said control means (26); a second correction factor map (Fig. 7). storing a second set of correction factors corresponding to various values of the revolutional speed of said engine; and said control means (26) being arranged such that when said load state judgement means judges threre is no highly loaded state said control means reads out a correct factor corresponding to the revolutional speed of said engine detected at that time by said revolutional speed detection means and the basic valve opening pulse width calculated at that time by said calculation means to thereby correct the basic valve opening pulse width calculated at that time with the read-out correction factor, while when said load state judgement means judges there is a highly loaded state said control means reads out a correct factor corresponding to the revolutional speed of said engine detected at that time by said . revolutional speed detection means and the basic valve opening pulse width calculated at that time by said calculation means and further reads out another correction factor to thereby correct the basic valve opening pulse width calculated at that time with a sum of said two read-out correction factors, said control means supplying said injection valve means with a valve opening pulse having the thus corrected pulse width.

Claim 8

A fuel injection apparatus for an internal combustion engine, comprising: fuel injection valve means (40) for supplying said engine with fuel; air flow rate detection means (36) for detecting a quantity of air sucked by said engine; engine revolutional speed detection means (23) for detecting a revolutional speed of said engine; load state judgement means (26) for judging whether said engine is in a highly loaded state or not; control means (26) for calculating a basic pulse width of a valve opening pulse for said injection valve means on the basis of respective output signals of said air flow detection means and said engine speed detection means; a first correction factor map (Fig. 5) storing a first set of predetermined correction factors cor=e-sponding to various values of the revolutional speed of said engine and various values of the valve opening pulse width for said injection valve means (40) to be calculated by said control means (26); a second correction factor map (Fig. 7). storing a second set of correction factors corresponding to various values of the revolutional speed of said engine; and said control means (26) being arranged such that when said load state judgement means judges threre is no highly loaded state said control means reads out a correct factor corresponding to the revolutional speed of said engine detected at that time by said revolutional speed detection means and the basic valve opening pulse width calculated at that time by said calculation means to thereby correct the basic valve opening pulse width calculated at that time with the read-out correction factor, while when said load state judgement means judges there is a highly loaded state said control means reads out a correct factor corresponding to the revolutional speed of said engine detected at that time by said . revolutional speed detection means and the basic valve opening pulse width calculated at that time by said calculation means and further reads out another correction factor to thereby correct the basic valve opening pulse width calculated at that time with a sum of said two read-out correction factors, said control means supplying said injection valve means with a valve opening pulse having the thus corrected pulse width.

Claim 9

A fuel injection apparatus in an internal combustion engine according to Claim 6, in which said load state judgement means (26) judges whether said engine is in a highly loaded state or not on the basis of the revolutional speed of said engine detected by said engine revolutional speed detection means and the basic valve opening pulse width calculated by said control means.

Claim 10

A fuel injection apparatus in an internal combustion engine according to Claim 7, in which said load state judgement means (26) has a threshold map (Fig. 6) in which various threshold values of the basic valve' opening pulse for judging the load state corresponding to the revolutional speed of said engine are predetermined in advance, so as to judge said engine to be in a highly loaded state when said calculated basic pulse width has a value larger than a threshold value in said threshold map corresponding to the revolutional speed of said engine detected by said engine revolutional speed detection means.

Claim 11

A fuel injection apparatus in an internal combustion engine according to Claim 8, in which said threshold value varies depending on the revolutional speed of said engine.

Claim 12

A fuel injection apparatus in an internal combustion engine according to Claim 9, in which having judged once that said engine is in a highly loaded state, said load state judgement means (26) judges that said engine is in said highly loaded state unless the basic valve opening pulse width is reduced to a value lower than one of said threshold values corresponding to the revolutional speed of said engine by a predetermined ratio.