Abstract A method of controlling the quantity of fuel to be injected into an intake manifold (2) for an engine (1) by a fuel injection unit (5) comprising the steps of identifying parameters indicative of a change in the dynamic characteristic of the fuel supply system due to changes in the environmental conditions including the atmospheric pressure and engine temperature, estimating the quantity of fuel to be supplied to the engine cylinder on the basis of the identified parameters, and controlling the quantity of fuel to be injected so that the ratio between the measured quantity of air supplied to the engine cylinder and the estimated quantity of fuel supplied to the engine cylinder attains the desired air-fuel ratio.
A method of fuel injection control in an engine control apparatus in which the quantity of fuel injected by fuel injection means (5) is controlled to maintain the air-fuel ratio at the desired value on the basis of an information output from an air-fuel ratio sensor (7) sensing the air-fuel ratio between the quantities of air and fuel supplied to a cylinder of an engine (1) and an information output from an air flow meter (6), an intake manifold pressure sensor or an engine rotation speed sensor (4) indicating the quantity of air supplied to the engine cylinder, characterized by following steps: a) identifying parameters indicative of a change in the dynamic characteristic of the fuel supply system due to changes in the environmental conditions on the basis of computations on the signals indicative of the air-fuel ratio, quantity of supplied air and engine rotation speed together with the signal indicative of the quantity of fuel injected by said fuel injection means, b) estimating the quantity of fuel actually supplied to the engine cylinder due to an observation delay from said air-fuel ratio sensor owing to a retarded flow of exhaust gases in the exhaust manifold, on the basis of the parameters identified in step a), and c) controlling the quantity of fuel to be injected by said fuel injection means so that the ratio between the measured quantity of air supplied to the engine cylinder and the estimated quantity of fuel supplied to the engine cylinder attains the desired air-fuel ratio.
Claim 2
Independent Claim
252 words
A method of fuel injection control in an engine control apparatus in which the quantity of fuel injected by fuel injection means (5) is controlled to maintain the air-fuel ratio at the desired value on the basis of an information output from an air-fuel ratio sensor (7) sensing the air-fuel ratio between the quantities of air and fuel supplied to a cylinder of an engine (1) and an information output from an air flow meter (6), an intake manifold pressure sensor or an engine rotation speed sensor (4) indicating the quantity of air supplied to the engine cylinder, characterized by following steps: a) identifying parameters indicative of a change in the dynamic characteristic of the fuel supply system due to changes in the environmental conditions on the basis of computations on the signals indicative of the air-fuel ratio, quantity of supplied air and engine rotation speed together with the signal indicative of the quantity of fuel injected by said fuel injection means, b) estimating the quantity of fuel actually supplied to the engine cylinder due to an observation delay from said air-fuel ratio sensor owing to a retarded flow of exhaust gases in the exhaust manifold, on the basis of the parameters identified in step a), and c) controlling the quantity of fuel to be injected by said fuel injection means so that the ratio between the measured quantity of air supplied to the engine cylinder and the estimated quantity of fuel supplied to the engine cylinder attains the desired air-fuel ratio.
Claim 3
Dependent Claim
43 words
A method as claimed in Claim 1, wherein, when said intake manifold pressure sensor is not provided, the quantity of air supplied to the engine cylinder is estimated on the basis of the quantity of air measured by said air flow meter (6).
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