Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – With indicator or control of power plant
Reexamination Certificate
2002-02-13
2004-04-27
Wolfe, Willis R. (Department: 3747)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
With indicator or control of power plant
C701S110000, C123S090150, C073S117020
Reexamination Certificate
active
06728624
ABSTRACT:
This application claims the priority of Italian Application No. B02001A 000076 filed Feb. 13, 2001, the disclosure of which is being incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention concerns a method for estimating the filling of a cylinder in an internal combustion engine.
This invention can be advantageously applied in internal combustion engines with variable cam stroke, to which the following description will explicitly refer without losing out in general terms.
The known internal combustion engines are provided with a control unit which, at every engine cycle, determines the adjustment values for optimising combustion in the individual cylinders in order to obtain maximum efficiency possible in all operating conditions. To determine these adjustment values (for example opening of the throttle valve, injection advance, injection duration), the control unit requires certain information concerning the current operating status of the engine; among this information, estimation of the filling of each cylinder is important, i.e. estimation of the mass of fresh air (combustion agent) sucked in by each cylinder during the induction phase.
Estimation of the filling of each cylinder is particularly complicated in internal combustion engines with variable cam stroke because modification of the induction and/or exhaust phase affects the cylinder filling capacity, thus modifying the “acoustic” characteristics of the induction and/or exhaust subsystems. In particular, the actual position of the stroke variator in induction/exhaust with respect to the rest position determines both the different induction capacity of the cylinders and the amount of exhaust gas trapped inside them.
To estimate the filling of each cylinder, an air flow rate meter is normally used, fitted upstream of the cylinder inlet valve; the use of air flow rate meters is expensive, however, due to the high cost of the devices themselves.
Another known solution for estimating the filling of each cylinder is to parameterise reconstruction of the cylinder load in two-dimensional planes according to assigned induction/exhaust timing values; by linear interpolation between two adjacent two-dimensional planes, the cylinder filling is determined for all permitted induction/exhaust timing values. Again, however, this solution is fairly expensive as it involves the use of a large-capacity and therefore costly memory in the control unit to store all the necessary two-dimensional planes; furthermore, said solution requires fairly lengthy engine test bench set-up times.
SUMMARY OF THE INVENTION
The aim of the present invention is to provide a method for estimating the filling of a cylinder in an internal combustion engine which has none of the disadvantages described and, in particular, is easy and inexpensive to implement.
According to one embodiment of the present invention, a method is provided for estimating the filling of the cylinder in an internal combustion engine that includes estimation of a theoretical induction efficiency which the cylinder would have if it operated with an optimum induction/exhaust timing value (VVT), i.e. with the induction/exhaust timing value (VVT) that permits maximisation of the mass (m
a
) of a combustion agent that can be sucked in by the cylinder, determination of the value of a correction factor (K
vvt
) according to the induction/exhaust timing value (VVT) actually used an estimation of induction efficiency, i.e. a standardized measurement of the filling of the cylinder, multiplying the theoretical induction efficiency by correction factor (K
vvt
).
REFERENCES:
patent: 4633403 (1986-12-01), Asmus
patent: 5211146 (1993-05-01), Pischinger
patent: 5520153 (1996-05-01), Milunas
patent: 5690065 (1997-11-01), Janse van Vuuren
patent: 5714683 (1998-02-01), Maloney
patent: 6371066 (2002-04-01), Cullen
patent: 199 06 707 (2000-08-01), None
patent: WO 01 42641 (2001-06-01), None
Minichetti Jean Charles
Palazzi Alessandro
Kinberg Robert
Magneti Marelli Powertrain S.p.A.
Venable LLP
Voorhees Catherine M.
Wolfe Willis R.
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