RFID Tag Crankshaft Position Sensing for Engine Start-Up
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Solution Overview
Problem
Current internal combustion engines face delays in engine start-up due to reliance on pattern recognition methods for determining crankshaft and camshaft positions, which require a complete revolution and can be faulty, leading to delayed fuel and spark delivery.
Innovation Solution
A system using RFID tags positioned around the perimeter of the crankshaft and camshaft wheels, with an RFID transceiver to immediately determine the wheel's position by transmitting and receiving coded signals, enabling prompt engine control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pattern recognition method with removed teeth is used, then engine position can be determined, but engine start-up is delayed
Solution Approach 1:
The RFID tags are pre-positioned around the wheel at predetermined intervals, and their identification codes are predetermined. This preliminary setup eliminates the need for the wheel to complete a full revolution to determine position, as the transceiver can immediately identify which tag is closest and calculate position accordingly, thus reducing start-up time while maintaining measurement precision
Solution Approach 2:
The patent replaces the mechanical pattern recognition system (physical teeth and sensors detecting rising/falling edges) with an RFID-based electromagnetic system. The RFID transceiver uses radio frequency signals to interrogate tags and determine wheel position, eliminating the mechanical dependency on wheel rotation and sensor pulse detection, thereby enabling immediate position determination at start-up
2Reliability
If complete revolution of crankshaft is required, then reference location can be detected, but fuel and spark delivery is delayed
Solution Approach 1:
Reference locations are predetermined by placing RFID tags at specific angular intervals around the wheel, with at least one tag positioned at the desired reference location. This eliminates the need for the crankshaft to complete a full revolution to establish reference, as the system immediately knows the position based on which tag is detected, enabling immediate fuel and spark delivery
Solution Approach 2:
The mechanical reference detection method (physical teeth alignment with sensor) is replaced with RFID tag detection using electromagnetic fields. The transceiver can detect the reference tag immediately upon wheel rotation without requiring mechanical alignment and pulse counting, thus improving productivity by enabling immediate fuel and spark delivery while maintaining reliable reference location detection
3Measurement precision
If magnetic reluctant sensor or Hall effect sensor is used, then wheel position can be sensed, but sensor faults may occur
Solution Approach 1:
The patent replaces magnetic sensors (magnetic reluctant or Hall effect sensors) with an RFID-based electromagnetic system. Instead of detecting changes in magnetic field caused by physical teeth, the RFID transceiver uses radio frequency signals to interrogate passive tags attached to the wheel. This substitution eliminates sensor drift, magnetic interference, and mechanical wear issues while maintaining precise wheel position sensing capability
Solution Approach 2:
The RFID tag acts as an intermediary between the wheel and the transceiver. Rather than having the sensor directly detect wheel features, the tag carries the position information and communicates it wirelessly to the transceiver. This intermediary approach isolates the sensing system from mechanical and magnetic interference, improving reliability while maintaining measurement precision
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
Enables immediate determination of engine position, allowing for quicker engine start-up and reliable fuel and spark delivery by providing accurate position sensing independent of wheel orientation.
Implementation Method 1
A plurality of RFID tags are disposed at predetermined intervals around the wheel, and an RFID transceiver is positioned proximate the wheel. As the wheel rotates, the RFID transceiver transmits a signal that interrogates the RFID tags
Data Source
AI summary
A system for determining the position of a rotating wheel using RFID. In one embodiment, the system includes a position sensing wheel mounted to one or both of a crankshaft and a camshaft in the engine. A plurality of RFID tags are disposed at predetermined intervals around the wheel, and an RFID transceiver is positioned proximate the wheel. As the wheel rotates, the RFID transceiver transmits a signal that interrogates the RFID tags, which then transmit a coded signal to the transceiver identifying the wheel's position relative to the transceiver. Therefore, regardless of the position of the wheel, the RFID transceiver can interrogate the closest RFID tag and immediately know the position of the engine so that an engine controller can provide fuel and spark to the cylinders as soon as possible.