Abstract: In an intake system for an internal combustion engine having an air filter with a fresh-air line opening into the fresh-air side of the air filter and a clean-air line leading from a clean-air side of the air filter to the internal combustion engine, an additional line which is in communication with the engine compartment extends into the fresh-air side of the air filter starting from the engine compartment, so as to be tapered in the direction toward the clean air side of the air filter with the inlet opening of the additional line being directed toward the adjacent passenger compartment.

Abstract: In an intake system for an internal combustion engine having a cylinder head with at least one inlet duct per cylinder, an essentially flat control flap is supported in the inlet duct on a pivot shaft pivotally about an axis which is disposed in spaced relationship upstream from the control flap by way of side support arms such that, in an open position, the control flap rests against a wall portion of the inlet duct from where it can be swiveled into the intake duct into a flow directing turbulence generating position.

Abstract: In a method for detecting knocking combustion during the operation of an internal combustion engine with a device for measuring the ionic current, the raw ionic current signal or the evaluated value of the knocking intensity are normalized. This enables the value of the knocking intensity to be reliably compared with a threshold value. The normalization avoids the falsifying influence of large intensity fluctuations of the raw ionic current signal from one combustion cycle to the next without any relation to the true knocking intensity.

Abstract: In an intake system for an internal combustion engine having a cylinder head with at least one inlet duct per cylinder, an essentially flat control flap is supported in the inlet duct on a pivot shaft pivotally about an axis which is disposed in spaced relationship upstream from the control flap by way of side support arms such that, in an open position, the control flap rests against a wall portion of the inlet duct from where it can be swiveled into the intake duct into a flow directing turbulence generating position.

Abstract: The present invention relates to a method for detecting knocking combustion during the operation of an internal combustion engine with a device for measuring the ionic current, in which the raw ionic current signal or the evaluated value of the knocking intensity are normalized, which enables the value of the knocking intensity to be reliably compared with a threshold value.