Doppler Intrusion Sensor for Vehicle Key-Off Load Reduction
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Solution Overview
Problem
Vehicles experience a key-off load due to various actions even when turned off, which is difficult to reduce without sacrificing premium features or increasing battery size, weight, and fuel economy costs.
Innovation Solution
Incorporating an intrusion sensor to detect Doppler shifts in the passenger compartment, allowing the door ajar sensors to be turned off during key-off cycles, thereby reducing the key-off load while maintaining intrusion detection features, and using a smaller battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If door ajar sensors and other premium features are kept active during key-off cycles, then vehicle security and feature completeness are maintained, but key-off load increases requiring larger batteries
Solution Approach 1:
The system dynamically adjusts sensor operation modes based on vehicle state. During key-off cycles, the intrusion sensor transitions from a standard monitoring mode to a specialized Doppler-shift detection mode, which consumes less power while maintaining security. This dynamic adaptation allows the system to maintain security functionality while reducing energy consumption during specific operational phases.
Solution Approach 2:
The patent changes the operational parameters of the intrusion sensor by switching from traditional sensor types to Doppler-shift detection technology. This parameter change enables the system to detect intrusions through frequency shift analysis of reflected sound waves, which requires less power than continuous operation of traditional door ajar sensors, thereby reducing key-off load while maintaining security.
2Power
If larger batteries are installed to handle increased current draw, then key-off load capacity is improved, but vehicle weight and fuel economy worsen
Solution Approach 1:
The system implements periodic action by enabling intrusion detection during key-off cycles through Doppler-shift detection rather than continuous operation of traditional sensors. The ultrasonic transmitter sends periodic sound waves and the receiver detects frequency shifts, providing intermittent but effective monitoring. This periodic detection mechanism reduces average power consumption compared to continuous sensor operation, allowing smaller battery capacity and reduced vehicle weight.
3Measurement precision
If traditional door ajar sensors are used during key-off cycles, then door status monitoring is maintained, but current draw increases requiring larger batteries
Solution Approach 1:
The patent replaces mechanical door ajar sensors with an acoustic field-based Doppler detection system. Instead of using mechanical switches or contact-based sensors that require continuous power, the system uses ultrasonic waves to detect door movement through Doppler frequency shifts. This substitution eliminates the need for powered mechanical sensors during key-off cycles, reducing current draw and allowing for smaller battery size while maintaining detection 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
This approach reduces the key-off load by disabling non-essential sensors during key-off cycles, enabling the use of a smaller battery without compromising security features, thus improving fuel economy and reducing vehicle costs.
Implementation Method 1
an intrusion sensor configured to detect a Doppler shift in a passenger compartment
Data Source
AI summary
A vehicle includes an intrusion sensor configured to detect a Doppler shift in a passenger compartment and output an intrusion signal representing the Doppler shift. The vehicle further includes a processing device configured to receive the intrusion signal and activate an alarm if the Doppler shift exceeds a predetermined threshold. A method includes measuring a Doppler shift in a passenger compartment of a vehicle, comparing the Doppler shift to a predetermined threshold, and activating an alarm system if the Doppler shift exceeds the predetermined threshold.