Internal combustion engine and control method thereof

Abstract

In order to avoid a surge state of the compressor (5b) of a turbocharger (5), an ECU (20) is configured to be provided with a surge avoidance means (process) which, during vehicle deceleration, determines whether or not the compressor (5b) of the turbocharger (5) enters a surge state; if the compressor (5b) is determined to enter a surge state, then, as surge avoidance control, the surge avoidance means acquires a first target opening degree (TAn) of the nozzle vane (5c) of a turbine (5a) of the turbocharger (5) based on the driving state and a first opening degree map (M1); if the first target opening degree (TAn) is less than a pre-set surge avoidance first target opening degree (TAx), then the surge avoidance means controls the nozzle vane (5c) to the surge avoidance first target opening degree (TAx), and if the first target opening degree (TAn) is greater than or equal to the surge avoidance first target opening degree (TAx), controls the nozzle vane (5c) to the first target opening degree (TAn).

Description

technical field [0001] The present invention relates to an internal combustion engine and a control method thereof. The internal combustion engine includes a turbocharger having a turbine arranged in an exhaust passage, and a compressor arranged in an intake passage and driven by the turbine, so that the compressor can be prevented from being damaged. Surge condition. Background technique [0002] Conventionally, a turbocharger that rotates a turbine at a high speed with exhaust gas discharged from an engine and drives a compressor with the rotational force to send compressed air into the engine is provided, thereby effectively utilizing the energy of the exhaust gas. [0003] The turbocharger includes a wastegate turbocharger and the like, and the wastegate turbocharger is provided with a nozzle vane mounted on the turbine side of the turbocharger that controls the rotation speed of the engine according to the rotational speed of the engine. , thereby increasing boost effi...

AI Technical Summary

Problems solved by technology

[0010] In the device described in Patent Document 1, when the vehicle is decelerating, the opening of the EGR valve is controlled to the closed side relative to the opening set during normal operation, and the turbine nozzle opening is controlled to the open side, However, especially when the engine speed is high, excessive increase in EGR rate and boost pressure will affect other performances such as fuel consumption and exhaust gas.

[0011] In the device described in Patent Document 2, the diffuser vane is controlled using an opening map different from that in normal operation, but the control method using a plurality of opening maps can suppress excessive However, it is necessary to refer to multiple opening maps, and the control becomes complicated due to the increase in man-hours

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