Electric Vehicle Weight Determination Using Motor Torque and Acceleration
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Solution Overview
Problem
Electric and hybrid vehicle owners lack accurate methods to determine their vehicle's gross combined weight, which affects range estimates and operational efficiency, potentially leading to unsafe driving conditions due to unknown load weights.
Innovation Solution
A system and method that calculates the total weight of a vehicle by measuring drive force, speed, and longitudinal acceleration, using motor current, voltage, and motor speed to determine torque, and combining this data with accelerometer and engine torque information to account for both positive and negative drive forces, allowing for accurate weight determination and display to the driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vehicle weight is not measured using external scales, then vehicle owners cannot obtain accurate weight information, but using external scales requires loss of time and convenience
Solution Approach 1:
The vehicle uses its own existing sensors (accelerometer, motor current, voltage, speed sensors) to self-determine its weight without external assistance. The control unit calculates weight by processing data from these self-contained components, eliminating the need for external weighing scales and making the vehicle self-sufficient for weight measurement.
Solution Approach 2:
The patent replaces the mechanical/physical weighing scale system with an electronic calculation system. Instead of mechanically weighing the vehicle, the system uses electronic sensors to measure acceleration, motor current, voltage, and speed, then calculates weight through computational algorithms in the control unit.
2Reliability
If vehicle weight is unknown, then range estimates and operational efficiency cannot be optimized, but obtaining accurate weight requires complex measurement systems
Solution Approach 1:
The control unit performs multiple functions: it manages motor control, monitors vehicle operation, and simultaneously calculates weight determination. The existing sensor network serves both primary vehicle control functions and weight measurement functions, eliminating the need for dedicated weight measurement hardware and reducing overall system complexity.
Solution Approach 2:
The vehicle's existing control system serves dual purposes by incorporating weight determination capabilities into the primary control unit. The same sensors used for motor control (current, voltage, speed sensors) and the accelerometer are repurposed for weight calculation, making the system self-sufficient without additional specialized equipment.
3Ease of operation
If load weight is not monitored, then vehicle performance and safety cannot be optimized, but implementing weight monitoring requires additional sensors and processing
Solution Approach 1:
The system continuously monitors weight by processing real-time data from accelerometers and motor sensors, providing ongoing feedback to the control unit. This feedback mechanism enables dynamic adjustment of vehicle operation based on actual load conditions, improving performance and safety through continuous information about vehicle weight status.
Solution Approach 2:
The control unit integrates weight monitoring into its existing multi-function role. The same processing unit that manages motor control and vehicle operation also performs weight calculation and monitoring, eliminating the need for separate dedicated monitoring hardware and reducing system complexity while maintaining comprehensive vehicle management capabilities.
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
Provides accurate and real-time weight information to the driver, enhancing safety and operational efficiency by enabling informed decisions about vehicle performance and load management, eliminating the need for external weighing scales.
Implementation Method 1
an accelerometer configured to measure a longitudinal acceleration of the vehicle
Implementation Method 2
the motor current, voltage, and motor speed, must be known to determine the torque. This torque may be used to calculate a drive force
Data Source
AI summary
In various example embodiments, a system and method for determining a gross combined weight of an electric or hybrid vehicle and its load is disclosed. A method includes: providing predetermined calibration settings relating engine drive force to engine speed and electric motor drive force to motor speed for a vehicle travelling at various speeds, altering accelerometer data based on filtered vehicle pitch and roll data, determining that one or more vehicle performance parameters fall within a threshold range, storing a plurality of data pairs that include longitudinal acceleration and drive force, and determining a slope of a line that linearly approximates the plurality of data pairs, the slope indicating a total weight, the total weight comprising a weight of the vehicle and a weight being hauled by the vehicle; and transmitting the total weight to a display.