Cam Switching Device Noise Reduction via Controlled Pin Seating
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Solution Overview
Problem
Internal combustion engine systems experience collision noise during the operation of the cam switching device due to the protrusion of the engagement pin into the cam groove, which affects the quietness of the engine.
Innovation Solution
The cam switching device is controlled to seat the engagement pin on the forward outer peripheral surface of the camshaft before inserting it into the cam groove, reducing the stroke amount and protruding speed, thereby minimizing collision noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the engagement pin is directly protruded into the cam groove to switch cams, then the cam switching operation is completed, but collision noise occurs during the protruding operation
Solution Approach 1:
The engagement pin is made to contact the forward outer peripheral surface of the camshaft before being inserted into the cam groove. This preliminary action allows the pin to be gradually guided into the groove, reducing the protruding speed and preventing direct impact, thereby suppressing collision noise while completing the cam switching operation
Solution Approach 2:
The forward outer peripheral surface of the camshaft serves as an intermediary element between the engagement pin and the cam groove. By contacting this intermediate surface first, the engagement pin's insertion is softened and controlled, reducing the harmful collision noise during the cam switching process
Data Source
AI summary
An internal combustion engine system is provided with a cam switching device including a cam groove provided on the outer peripheral surface or a camshaft and an actuator capable of protruding, toward the camshaft, an engagement pin that is engageable with the cam groove. The internal combustion engine system is configured, in causing the cam switching device to perform a cam switching operation, to control the actuator such that the engagement pin is seated on a forward outer peripheral surface which is located more forward than an end of the cam groove on the forward side with respect to an insert section of the cam groove in the rotational direction of the camshaft.