Flexplate Torque Sensing via Strain Gauges
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Solution Overview
Problem
Conventional engine torque sensors are complex, costly, and have packaging and reliability issues, limiting their implementation in mass production and providing insufficient bandwidth for advanced powertrain control strategies.
Innovation Solution
A direct engine torque sensing system that measures deformations on a flexplate, using sensors attached to the disk transmitting torque to the gearbox, offering a larger surface area for measurement and reduced complexity, with strain gauges and piezoelectric components to generate and transmit strain-related data for accurate torque calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional crankshaft-mounted sensors are used for direct torque measurement, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent uses strain gauges that create an electrical copy of the mechanical strain on the flexplate through the Wheatstone bridge circuit. This electrical signal replicates the torque information without requiring complex mechanical sensing elements on the crankshaft, thereby maintaining measurement precision while reducing device complexity
Solution Approach 2:
The patent replaces complex mechanical torque sensing mechanisms with an electrical measurement system. Strain gauges convert mechanical deformation into electrical signals that can be processed electronically, substituting mechanical complexity with simpler electrical components and signal processing
2Measurement precision
If conventional crankshaft-mounted sensors are used, then torque measurement capability is improved, but packaging space requirements increase
Solution Approach 1:
The patent transitions from measuring torque directly on the cylindrical crankshaft surface to measuring it on the flat, two-dimensional surface of the flexplate. This dimensional change provides abundant mounting area for strain gauges and associated electronics, eliminating packaging space constraints while maintaining torque measurement capability
3Measurement precision
If conventional direct torque sensors are implemented, then torque measurement accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs inexpensive strain gauge elements that can be mass-produced and replaced if necessary. These simple resistive sensors are far cheaper than complex mechanical torque sensors, enabling accurate torque measurement at a cost suitable for mass production while maintaining measurement precision
Solution Approach 2:
The patent changes the measurement parameter from direct mechanical torque sensing to electrical resistance measurement. By measuring the change in electrical resistance of strain gauges in response to mechanical strain, the system achieves accurate torque measurement using low-cost electrical components instead of expensive mechanical sensors
4Measurement precision
If conventional torque sensors are used, then basic torque measurement is achieved, but bandwidth is insufficient for advanced control strategies
Solution Approach 1:
The patent replaces mechanical torque sensing with electrical measurement using strain gauges and Wheatstone bridges. Electrical signals have inherently higher bandwidth and faster response times compared to mechanical systems, enabling the sensor to capture rapid torque transients and support advanced control strategies requiring high measurement speed
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
Facilitates faster and more accurate engine torque measurement, improving powertrain calibration, driveability, and transmission control with lower costs and minimal modifications, enabling real-time feedback for efficient engine torque control.
Implementation Method 1
The sensor may include at least one strain gauge attached to the flexplate
Implementation Method 2
with strain gauges and piezoelectric components to generate and transmit strain-related data
Data Source
AI summary
An engine torque sensory system (10), adapted for use with an engine-driven vehicle (12) having a flexplate (18), including at least one sensor (26) fixedly attached on the surface of the flexplate (18) and operable to detect deformations along the surface of the flexplate (18) caused by the generated engine torque, and further including a receiver (28) communicatively coupled to the sensor (26), spaced from the rotating flexplate (18), and operable to convert sensor readings to correlative engine torque values.