US 9,309,814 B2 · Method and device for controlling a variable valve train of an internal combustion engine

Abstract

A method for controlling a variable valve train of an internal combustion engine including multiple cylinders is disclosed. At a first operating point of the engine, an intake air amount is determined and cylinder-individual values for a fuel amount reduction are determined by successively reducing the respectively supplied fuel amount for each cylinder until a characteristic representing uneven running of the engine has reached a predetermined uneven running threshold value. A ratio of a change in the intake valve lift to the resulting change in the intake air amount is determined for the first operating point. Cylinder-individual deviations of the intake valve lift from a reference value are determined based on the ratio, the intake air amount at the first operating point, and the associated value for the fuel amount reduction. The variable valve train is then controlled on the basis of the cylinder-individual deviations of the intake valve lift.

Claims10

Dependent claims

A method for controlling a variable valve train of an internal combustion engine with a plurality of cylinders, comprising:

determining an intake air quantity at a first operating point of the internal combustion engine,
at the first operating point, determining cylinder-specific values for a reduction of the fuel quantity by successively reducing the respective delivered quantity of fuel for each cylinder until a parameter representing the uneven running of the internal combustion engine has reached a specified uneven running limit value,
determining a ratio of a change of the inlet valve lift to a resulting change of the intake air quantity for the first operating point,
determining cylinder-specific deviations of the inlet valve lift from a valve reference value based on the ratio, the intake air quantity at the first operating point, and the associated fuel quantity reduction value, and
controlling the variable valve train based on at least one of the cylinder-specific deviations of the inlet valve lift.

2 more elements

A control device for an internal combustion engine with a plurality of inlet valves and a device for varying the lift of the inlet valves, wherein the control device is programmed to control a variable valve train of an internal combustion engine with a plurality of cylinders by:

determining an intake air quantity at a first operating point of the internal combustion engine,
at the first operating point, determining cylinder-specific values for a reduction of the fuel quantity by successively reducing the respective delivered quantity of fuel for each cylinder until a parameter representing the uneven running of the internal combustion engine has reached a specified uneven running limit value,
determining a ratio of a change of the inlet valve lift to a resulting change of the intake air quantity for the first operating point,
determining cylinder-specific deviations of the inlet valve lift from a valve reference value based on the ratio, the intake air quantity at the first operating point, and the associated fuel quantity reduction value, and
controlling the variable valve train based on at least one of the cylinder-specific deviations of the inlet valve lift.

2 more elements

Dependencies are inferred from the claim text.

Method and device for controlling a variable valve train of an internal combustion engine

Life of this patent

Method and device for controlling a variable valve train of an internal combustion engine

Life of this patent

Abstract

Claims10