Fuel supply control method for internal combustion engines under high load conditions

Claim 1

A method of electronically controlling the quantity of fuel being supplied to an internal combustion engine having an intake passage, and a throttle valve arranged in said intake passage, in response to operating conditions of said engine, so as to achieve desired air-fuel ratios of a mixture being supplied to said engine, the method comprising the steps of: (a) detecting the rotational speed of said engine; (b) detecting absolute pressure in said intake passage of said engine at a zone downstream of said throttle valve therein; (c) detecting the valve opening of said throttle valve; (d) comparing a detected value of the rotational speed of said engine with a predetermined value; (e) comparing a detected value of said intake passage absolute pressure with a first predetermined valve and also comparing a detected value of said throttle valve opening with a predetermined value, when the detected value of the rotational speed of said engine is lower than said predetermined value thereof; (f) determining that said engine is operating in a first predetermined mixture-enriching region, when at least one of the detected values of said intake passage absolute pressure and said throttle valve opening is higher or larger than a corresponding one of said first predetermined value and said predetermined value thereof as results of the comparisons of the step (e); (g) comparing the detected value of said intake passage absolute pressure with a second predetermined value, when the detected value of the rotational speed of said engine is higher than said predetermined value thereof; (h) determining that said engine is operating in a second predetermined mixture-enriching region, when the determined value of said intake passage absolute pressure is higher than said second predetermined value thereof as a result of the comparison of the step (g); and (i) controlling the air-fuel ratio of said mixture to a predetermined value smaller than a stoichiometic mixture ratio, when it is determined in the step (f) or the step (h) that said engine is operating in a corresponding one of said first and second predetermined mixture-enriching regions.

Claim 2

A method of electronically controlling the quantity of fuel being supplied to an internal combustion engine having an intake passage, and a throttle valve arranged in said intake passage, in response to operating conditions of said engine, so as to achieve desired air-fuel ratios of a mixture being supplied to said engine, the method comprising the steps of: (a) detecting the rotational speed of said engine; (b) detecting absolute pressure in said intake passage of said engine at a zone downstream of said throttle valve therein; (c) detecting the valve opening of said throttle valve; (d) comparing a detected value of the rotational speed of said engine with a predetermined value; (e) comparing a detected value of said intake passage absolute pressure with a first predetermined valve and also comparing a detected value of said throttle valve opening with a predetermined value, when the detected value of the rotational speed of said engine is lower than said predetermined value thereof; (f) determining that said engine is operating in a first predetermined mixture-enriching region, when at least one of the detected values of said intake passage absolute pressure and said throttle valve opening is higher or larger than a corresponding one of said first predetermined value and said predetermined value thereof as results of the comparisons of the step (e); (g) comparing the detected value of said intake passage absolute pressure with a second predetermined value, when the detected value of the rotational speed of said engine is higher than said predetermined value thereof; (h) determining that said engine is operating in a second predetermined mixture-enriching region, when the determined value of said intake passage absolute pressure is higher than said second predetermined value thereof as a result of the comparison of the step (g); and (i) controlling the air-fuel ratio of said mixture to a predetermined value smaller than a stoichiometic mixture ratio, when it is determined in the step (f) or the step (h) that said engine is operating in a corresponding one of said first and second predetermined mixture-enriching regions.

Claim 7

A method of electronically controlling the quantity of fuel being supplied to an internal combustion engine having an intake passage, and a throttle valve arranged in said intake passage, in response to operating conditions of said engine, so as to achieve desired air-fuel ratios of a mixture being supplied to said engine, the method comprising the steps of: (a) detecting the rotational speed of said engine; (b) detecting absolute pressure in said intake passage of said engine at a zone downstream of said throttle valve therein; (c) detecting the valve opening of said throttle valve; (d) comparing a detected value of the rotational speed of said engine with a predetermined value; (e) comparing a detected value of said intake passage absolute pressure with a first predetermined value, when the detected value of the rotational speed of said engine is lower than said predetermined value thereof; (f) determining that said engine is operating in a first predetermined mixture-enriching region, when the detected value of said intake passage absolute pressure is higher than said first predetermined value thereof as a result of the comparison of the step (e); (g) comparing the detected value of said throttle valve opening with a predetermined value, when the detected valve of said intake passage absolute pressure is lower than said first predetermined value thereof; (h) determining that said engine is operating in a second predetermined mixture-enriching region, when the detected value of said throttle valve opening is larger than said predetermined value thereof as a result of the comparison of the step (g); (i) comparing the detected value of said intake passage absolute pressure with a second predetermined value, when the detected value of predetermined value thereof; (j) determining that said engine is operating in a third predetermined mixture-enriching region, when the detected value of said intake passage absolute pressure is higher than said second predetermined value thereof; (k) controlling the air-fuel ratio of said mixture to a predetermined value smaller than a stoichiometic mixture ratio, when it is determined in the step (f), the step (h), or the step (j) that said engine is operating in a corresponding one of said first, second and third predetermined mixture-enriching regions.

Claim 8

A method of electronically controlling the quantity of fuel being supplied to an internal combustion engine having an intake passage, and a throttle valve arranged in said intake passage, in response to operating conditions of said engine, so as to achieve desired air-fuel ratios of a mixture being supplied to said engine, the method comprising the steps of: (a) detecting the rotational speed of said engine; (b) detecting absolute pressure in said intake passage of said engine at a zone downstream of said throttle valve therein; (c) detecting the valve opening of said throttle valve; (d) comparing a detected value of the rotational speed of said engine with a predetermined value; (e) comparing a detected value of said intake passage absolute pressure with a first predetermined value, when the detected value of the rotational speed of said engine is lower than said predetermined value thereof; (f) determining that said engine is operating in a first predetermined mixture-enriching region, when the detected value of said intake passage absolute pressure is higher than said first predetermined value thereof as a result of the comparison of the step (e); (g) comparing the detected value of said throttle valve opening with a predetermined value, when the detected valve of said intake passage absolute pressure is lower than said first predetermined value thereof; (h) determining that said engine is operating in a second predetermined mixture-enriching region, when the detected value of said throttle valve opening is larger than said predetermined value thereof as a result of the comparison of the step (g); (i) comparing the detected value of said intake passage absolute pressure with a second predetermined value, when the detected value of predetermined value thereof; (j) determining that said engine is operating in a third predetermined mixture-enriching region, when the detected value of said intake passage absolute pressure is higher than said second predetermined value thereof; (k) controlling the air-fuel ratio of said mixture to a predetermined value smaller than a stoichiometic mixture ratio, when it is determined in the step (f), the step (h), or the step (j) that said engine is operating in a corresponding one of said first, second and third predetermined mixture-enriching regions.