Vehicle Torque Control via Accelerometer Verification
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Solution Overview
Problem
Conventional methods for determining whether a vehicle's powertrain is delivering the correct amount of torque based on driver demand become complex in hybrid electric vehicles with multiple prime movers, as they rely on indirect measurements of engine speed and fluid flow rates, which are not reliable or efficient.
Innovation Solution
A control system that monitors the accelerator control signal and measures the vehicle's rate of acceleration and yaw rate using an accelerometer, allowing for direct determination of torque correspondence and enabling adjustments to torque application by the powertrain, including the option to apply negative torque or disconnect prime movers to prevent unintended acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If indirect measurements of engine speed and fluid flow rates are used to determine torque, then the system complexity is reduced and manufacturing cost is lowered, but the measurement precision and reliability of torque determination deteriorate
Solution Approach 1:
The patent replaces indirect mechanical measurement methods (engine speed and fluid flow rate calculations) with direct mechanical measurement using an accelerometer to measure vehicle acceleration. This substitution provides more reliable torque verification while maintaining system simplicity, as the accelerometer directly measures the physical effect of torque on vehicle motion without requiring complex multi-parameter calculations.
2Power
If multiple prime movers are used in hybrid electric vehicles, then the power and versatility of the vehicle is improved, but the complexity of monitoring and verifying torque delivery increases
Solution Approach 1:
The patent applies a universal monitoring approach using a single accelerometer device that can verify torque delivery from multiple different prime movers (engine and electric motor) regardless of their type or configuration. This multi-functional system simplifies the monitoring of complex hybrid powertrains by using one measurement device to verify the combined torque output of all prime movers, eliminating the need for separate monitoring systems for each power source.
3Measurement precision
If direct torque measurement devices such as strain gauges on crankshaft are installed, then the measurement precision of torque is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent introduces an intermediary measurement approach by measuring vehicle acceleration rather than directly measuring torque at the crankshaft. The accelerometer measures the intermediate physical quantity (vehicle acceleration) that results from torque application, providing reliable torque verification without the complexity and cost of direct crankshaft instrumentation. This intermediary measurement bypasses the need for complex direct torque sensors while maintaining measurement accuracy.
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 approach provides a reliable and efficient method to ensure the vehicle responds correctly to driver inputs by directly measuring acceleration, reducing the risk of unintended acceleration and enabling independent verification of torque delivery without the need for multiple torque measuring devices, thus enhancing safety and performance.
Implementation Method 1
an accelerometer device operable to measure a rate of acceleration and a yaw rate of the vehicle
Data Source
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AI summary
The present invention relates to a control system for a vehicle (100), the system comprising: control means operable to monitor an accelerator control signal of the vehicle and to control a powertrain of the vehicle to apply an amount of torque to one or more wheels (111, 112,114, 115) of the vehicle (100) corresponding to the accelerator control signal, the powertrain comprising prime mover means (121, 123); and means for determining whether the measured rate of acceleration of the vehicle and the accelerator control signal have an expected correspondence, wherein if the measured rate of acceleration and the accelerator control signal do not have the expected correspondence, the control means is operable to command a change in the amount of torque applied to the one or more wheels by the powertrain.