Sensor Assembly for Sliding Camshaft Position Detection
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Solution Overview
Problem
Current sensors for variable valve actuation systems in internal combustion engines are prone to mechanical damage, internal short circuits, and interrupted connections, necessitating a more reliable sensor assembly for detecting camshaft positions and angular speeds.
Innovation Solution
A sensor assembly with a detection element having distinct annular profiles for different camshaft positions, coupled with sensors that generate unique signals indicative of axial and angular positions, and angular speeds, allowing for accurate monitoring and actuation of valve operations without dedicated camshaft angular position sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple separate sensors (barrel sensors, camshaft trigger wheel sensor) are used to detect camshaft position and angular speed, then detection coverage is improved, but device complexity and reliability worsen due to multiple connection points and potential failure modes
Solution Approach 1:
The patent combines multiple detection functions (axial position detection and angular position/speed detection) into a single integrated sensor assembly. The sensor head simultaneously reads both the annular profile features on the camshaft barrel and the trigger wheel teeth, eliminating the need for separate barrel sensors and camshaft trigger wheel sensors, thus reducing device complexity while maintaining comprehensive detection coverage
Solution Approach 2:
The single sensor assembly performs multiple functions: it detects axial position of the camshaft barrel through annular profile features, detects angular position through trigger wheel teeth, and derives angular speed from the trigger wheel signals. This multi-functional sensor replaces what would traditionally require multiple specialized sensors, reducing the number of connection points and potential failure modes
2Measurement precision
If multiple separate sensors are used to detect camshaft parameters, then detection capability is improved, but reliability worsens due to increased risk of mechanical damage, internal short circuits, and interrupted connections
Solution Approach 1:
By merging multiple detection functions into a single sensor assembly with one electrical connection point, the patent eliminates multiple potential failure points. The single connector design removes the risk of interrupted connections between multiple sensors and the control unit, while the integrated structure reduces mechanical damage risks associated with multiple separate sensor components
Solution Approach 2:
The universal sensor assembly that performs axial position detection, angular position detection, and speed calculation in one unit reduces the overall sensor count. Fewer sensors mean fewer potential failure modes including mechanical damage, internal short circuits, and connection interruptions, thereby improving system reliability while maintaining comprehensive detection capability
3Measurement precision
If dedicated camshaft angular position sensors are used, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The sensor assembly achieves angular position detection as part of its multi-functional capability. By reading the trigger wheel teeth mounted on the camshaft, the sensor generates signals that provide angular position information without requiring a dedicated angular position sensor. This integrated approach maintains measurement accuracy while reducing device complexity
Data Source
AI summary
A sensor assembly for a sliding camshaft of a motor vehicle is provided. The sliding camshaft includes a base shaft that extends along a longitudinal axis and rotates about the longitudinal axis. The sliding camshaft further includes lobe banks rotationally fixed to the base shaft. Each lobe bank is axially movable between first and second positions relative to the base shaft. The sensor assembly includes a detection element rotationally fixed relative to the base shaft and axially movable between first and second positions relative to the base shaft. The sensor assembly further includes a sensor operably coupled to the detection element and configured to generate a signal indicative of an axial position of the detection element relative to the base shaft and at least one of an angular speed of the base shaft and an angular position of the base shaft about the longitudinal axis.