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

Abstract

An improved method for controlling a variable valve train (80, 110) of an internal combustion engine (1) having a plurality of cylinders (2) is disclosed, wherein each Each cylinder (2) reduces the amount of fuel supplied to each cylinder until it reaches a predetermined limit value of rough driving. The variable valve train ( 80 , 110 ) is controlled taking into account a cylinder-specific fuel quantity reduction value in a first operating point.

Description

technical field [0001] The invention relates to a method and a device for controlling a variable valve train of an internal combustion engine having a plurality of cylinders. Background technique [0002] In an effort to further reduce the fuel consumption and pollutant emissions of modern internal combustion engines, internal combustion engines with variable valve trains for variably controlling the intake and / or exhaust valves are increasingly being used. In this case, internal combustion engines with variable valve lift control and / or variable control of the valve opening times have proven to be particularly effective, since they can be operated virtually without throttle in the low and medium load range ( fully open the throttle valve) for operation. Among them, the load control is realized only by the lift or opening time of the intake valve. In this unthrottled operating range, there are fewer gas exchange losses, which lead to reduced consumption. However, producti...

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Problems solved by technology

However, manufacturing-induced tolerances in the valve train and the valves produce deviations in the filling of the cylinders

Especially in the low load range and idling speed (intake valve lift or opening time is very small in unthrottled operation), compared with the perceivable torque difference, the deviation in cylinder filling is clearly already small, and this limited driving comfort

Torque differences can arise not only between different internal combustion engines, but also between cylinders of the same internal combustion engine, which in the worst case lead to a perceived rough ride in the low load range or at idle speed and thus to Reduced ride comfort

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