Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
174 words
A system for controlling fuel metering for an internal combustion engine having a plurality of cylinders, including: an air/fuel ratio sensor installed at an exhaust system of the engine for detecting an air/fuel ratio of the engine; engine operating condition detecting means for detecting engine operating conditions at least including engine speed and engine load; fuel injection quantity determining means for determining a quantity of fuel injection TiM-F, Tcyl for individual cylinders at least based on the detected engine operating conditions; feedback loops having a plurality of controllers that input an output of said air/fuel ratio sensor as a controlled variable and operate with a manipulated variable of the quantity of fuel injection to determine feedback correction coefficient KFB such that the controlled variable KACT, Gfuel is brought to a desired value KCMD, Gfuel-str; and a fuel injector for injecting fuel in the individual cylinders of the engine in response to the manipulated variable; wherein: at least one of the controllers is input with the output of the air/fuel ratio sensor through a filter.
Claim 2
Dependent Claim
31 words
A system according to claim 1, wherein said plurality of controllers are input with the output of the air/fuel ratio sensor through respective filters whose characteristics are different from each other.
Claim 3
Dependent Claim
97 words
A system according to claim 1 or 2, further including: individual cylinder air/fuel ratio estimating means comprising: a model describing behavior of the exhaust system of the engine and inputting an output of said air/fuel ratio sensor; observing means for observing an internal state of the exhaust system described by said model; and estimating means for estimating the air/fuel ratios of the individual cylinders based on an output of said observing means; and wherein at least one of the controllers calculates the feedback correction coefficient for individual cylinders of the engine based on the estimated air/fuel ratio.
Claim 4
Independent Claim
51 words
A system according to any of preceding claims 1 to 3, wherein at least one of the controllers is a controller based upon a control law expressed in a recursion formula and calculates the feedback correction coefficient using the controlled variable and the manipulated variable in accordance with the recursion formula.
Claim 5
Independent Claim
22 words
A system according to any of preceding claims 1 to 4, wherein at least one of the filters is a low-pass filter.
Claim 6
Independent Claim
144 words
A system according to any of preceding claims 1 to 5, further including: individual cylinder air/fuel ratio estimating means comprising: a model describing behavior of the exhaust system of the engine and inputting an output of said air/fuel ratio sensor through a first filter; observing means for observing an internal state of the exhaust system described by said model; and estimating means for estimating the air/fuel ratios of the individual cylinders based on an output of said observing means; and said plurality of controllers includes a first controller that calculates feedback correction coefficient based on the estimated air/fuel ratio, and a second controller using a control law expressed in a recursion formula that calculates a feedback correction coefficient using an input of the air/fuel ratio sensor through a second filter as the controlled variable and the manipulated variable in accordance with the recursion formula.
Claim 7
Dependent Claim
15 words
A system according to claim 6, wherein said first and second filters are low-pass filters.
Claim 8
Dependent Claim
25 words
A system according to claim 7, wherein the low-pass filter of the second filter has a cutout frequency less than that of the first filter.
Claim 9
Independent Claim
50 words
A system according to any of preceding claims 1 to 8, wherein at least one of the controllers is a controller using a control law expressed in a recursion formula and calculates the feedback correction coefficient using the controlled variable and the manipulated variable in accordance with the recursion formula.