Axial Cam Shifting Position Detection via Hall Effect Sensor
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Solution Overview
Problem
Current axial cam shifting systems face challenges in accurately determining whether the camshaft is in the first or second position, which affects the optimization of valve lift profiles for improved fuel economy and reduced emissions.
Innovation Solution
The system incorporates an axial cam shifting assembly with a camshaft, first and second cam profiles, an actuator with pins, a carriage with a track, and a position sensor. A controller receives signals from the position sensor over a predetermined time, determining the carriage position based on edge detection and direction within a detection window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a two position axial cam shifting system is used to provide discrete valve lift profiles, then fuel economy and emissions are improved, but the ability to accurately determine camshaft position deteriorates
Solution Approach 1:
A magnetic marker is introduced as an intermediary element attached to the camshaft, and a magnetic sensor (such as a Hall effect sensor) is used to detect its position. This intermediary magnetic field-based system allows precise position detection without interfering with the mechanical two-position cam shifting mechanism, thereby maintaining fuel economy benefits while solving the position determination problem.
2Device complexity
If a simple actuation system with two discrete positions is used, then device complexity is reduced, but the reliability of position identification deteriorates
Solution Approach 1:
The mechanical position identification system is replaced with a magnetic field-based detection system. Instead of relying on mechanical features or complex mechanical sensors to determine camshaft position, a magnetic marker and magnetic sensor provide reliable electrical signal-based position identification, maintaining the simplicity of the mechanical actuation system while improving position identification reliability.
3Object-generated harmful factors
If discrete valve lift profiles are implemented through axial cam shifting, then emissions are reduced, but the difficulty of detecting and measuring camshaft position increases
Solution Approach 1:
A magnetic marker is introduced as an intermediary element attached to the camshaft, and a magnetic sensor (such as a Hall effect sensor) is used to detect its position. This intermediary magnetic field-based system allows precise position detection without interfering with the mechanical two-position cam shifting mechanism, thereby maintaining fuel economy benefits while solving the position determination problem.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables precise determination of the axial cam shifting system's position, allowing for accurate control of valve lift profiles, which improves fuel efficiency and reduces emissions.
Implementation Method 1
In one embodiment, the sensor is a hall-effect sensor.
Data Source
AI summary
An axial cam shifting system configured to selectively open and close engine valves includes an axial cam shifting assembly and a controller. The axial cam shifting assembly includes a camshaft, a first cam assembly, an actuator, a carriage and a position sensor. The first cam assembly is received on the camshaft and has two distinct cam profiles. The actuator has a first pin and a second pin. The carriage is arranged on the camshaft and defines a track that selectively receives the first and second pins, wherein the axial shifting cam assembly is movable between a first, and a second position corresponding to alignment of the respective two distinct cam profiles. The position sensor communicates a signal indicative of a position of the carriage. The controller receives the signal and determines whether the carriage is in one of the first and second positions based on the signal.