Apparatus for controlling internal combustion engine provided with turbocharger

Abstract

The present invention enables an exhaust gas to quickly pass through a spatial resonance region in an exhaust gas passage space ranging from a turbine housing to a catalyst, by increasing the flow velocity (VN passing flow velocity) of the exhaust gas passing through a nozzle vane when the exhaust gas reaches the spatial resonance region at the time of acceleration in an internal combustion engine provided with a variable nozzle vane turbocharger. When the exhaust gas reaches the spatial resonance region at the time of deceleration, the VN passing flow velocity is decreased to enable the exhaust gas to quickly pass through the spatial resonance region. By this control, it is possible to reduce the time during which the frequency of pressure pulsation generated at the rear end of the nozzle vane is amplified in the spatial resonance region. It is also possible to suppress the generation of abnormal noise caused by the pressure pulsation.

Description

technical field [0001] The present invention relates to a control device for an internal combustion engine with a supercharger, and more specifically, to a control device for an internal combustion engine including a variable nozzle diaphragm type supercharger. Background technique [0002] An internal combustion engine (hereinafter also referred to as an engine) mounted on a vehicle is equipped with a supercharger (hereinafter also referred to as a turbocharger) that utilizes exhaust energy. A turbocharger generally has a turbine that is rotated by exhaust gas flowing through the exhaust passage of the engine, and a compressor wheel that forcibly sends air in the intake passage to the combustion chamber of the engine. a chamber; and a connecting shaft connecting the aforementioned turbine and compressor wheels. In the turbocharger with such a structure, the energy of the exhaust gas is used to rotate the turbine arranged in the exhaust passage, and the impeller of the comp...

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Problems solved by technology

Furthermore, if the frequency of such pressure pulsation is amplified by the spatial resonance of the space in the turbine housing and the space in the exhaust pipe (exhaust gas passage from the turbine housing to the catalyst), it will become Discharge sound, the abnormal noise becomes a problem

[0010] Here, in order to avoid the above-mentioned pressure pulsation problem, even if it is intended to control the frequency of the space resonance of the turbine housing and the catalyst system, which is the main cause of the amplification, due to constraints such as supercharging efficiency, emissions, and installation requirements, the hardware design The degree of freedom is low, so it is difficult to suppress the generation of abnormal noise

Furthermore, even if the frequency of the spatial resonance is changed, since the pressure pulsation has a frequency component proportional to the flow velocity of the exhaust gas as described above, amplification (resonance) of the pulsation in the changed frequency band of the spatial resonance cannot be avoided.

[0011] In addition, it is also considered to add a sound-absorbing structure to the exhaust pipe of the vehicle, but due to the constraints of installation requirements, appearance, and cost, the degree of freedom in countermeasures for a single abnormal noise phenomenon is low

In addition, even if the vehicle countermeasures are taken against the sound emitted from the exhaust pipe of the vehicle, the problem of sound outside the vehicle remains (especially the problem of abnormal noise during idling (high-speed idling) while parked)

[0012] For the above reasons, in order to suppress the abnormal noise caused by the pressure pulsation generated at the rear end of the nozzle diaphragm, it is necessary to take countermeasures on the engine (turbocharger) side located upstream of the variable nozzle diaphragm mechanism, but the current situation is that the technology has not yet been established

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