Vehicle Sensor Assembly With Emergency Current Bypass
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Solution Overview
Problem
Existing sensor assemblies for vehicles lack effective emergency protection mechanisms to ensure continuous evaluation of sensor currents in case of voltage drops, leading to potential system failures and increased costs due to redundant sensor elements.
Innovation Solution
A sensor assembly with a first emergency protection circuit that monitors the low-side path and provides an alternative path when the voltage drop exceeds a breakover value, reducing the voltage drop to a holding value and allowing continuous evaluation of sensor currents, and optionally a second emergency protection circuit for the high-side path, with voltage detection and current sinks to manage sensor currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sensor assembly uses a single sensor element with emergency protection circuits, then cost is reduced and device complexity is minimized, but reliability is worsened due to potential voltage drops and measurement errors
Solution Approach 1:
The patent implements emergency protection circuits that are pre-configured to activate when voltage drops occur. These circuits include alternative measurement paths and protection elements (such as diodes or transistors) that are dormant during normal operation but automatically engage when voltage thresholds are exceeded, thereby cushioning against measurement errors and system failures before they can compromise reliability
Solution Approach 2:
The patent introduces intermediary protection circuits between the sensor element and the evaluation unit. These circuits act as mediators that monitor voltage levels and intervene when anomalies occur, providing an additional layer of protection without requiring redundant sensor elements. The intermediary circuits can redirect current paths or isolate faulty sections, maintaining system reliability while using a single sensor element
2Reliability
If emergency protection circuits are added to monitor voltage drops, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the emergency protection functions with the existing sensor assembly structure. The protection circuits are integrated into the same housing and electrical pathways as the sensor element, sharing common components such as connection terminals and evaluation units. This merging approach allows reliability enhancement without proportionally increasing device complexity, as the protection features are embedded within the existing architectural framework
Solution Approach 2:
The emergency protection circuits are designed to perform multiple functions: monitoring voltage drops, providing alternative measurement paths, protecting against overvoltage, and maintaining signal integrity. By making the protection circuits multi-functional, the patent achieves comprehensive reliability improvement without requiring separate dedicated components for each protective function, thereby limiting the increase in device complexity
3Device complexity
If the emergency protection circuit uses a Zener diode structure, then simplicity is maintained, but voltage drop is excessive leading to measurement errors
Solution Approach 1:
The patent changes the electrical parameters of the protection circuit by using active components (such as transistors or operational amplifiers) instead of passive Zener diodes. This parameter change allows for dynamic adjustment of voltage thresholds and current paths, enabling the circuit to maintain low voltage drops during normal operation while still providing protection when voltage exceeds safe levels. The active components can amplify weak signals and compensate for voltage losses, thereby maintaining measurement precision
4Reliability
If redundant sensor elements are used per measuring point, then reliability is improved, but cost increases
Solution Approach 1:
Instead of physically copying redundant sensor elements, the patent creates a functional copy through the emergency protection circuit's alternative measurement path. When the primary measurement path fails or experiences voltage drops, the protection circuit activates an alternative path that replicates the measurement function using the same sensor element. This virtual copying approach provides redundancy without the cost and complexity of installing multiple physical sensor elements at each measuring point
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
The solution enables continuous evaluation of sensor currents with reduced voltage drops, cost savings by using a single sensor element per measuring point, and enhanced reliability with redundant evaluation by two control devices, while automatically disconnecting alternative paths when voltage conditions are met.
Implementation Method 1
The first emergency protection circuit becomes active if the voltage drop at the second measuring connection of the sensor element exceeds, for example, a breakover voltage value which can be specified in the range from 2.0 V to 4.0 V
Implementation Method 2
The active first emergency protection circuit limits the voltage drop at the second measuring connection of the sensor element, for example, to a holding voltage value in the range from approximately 0.8 V to 1.5 V and is able to accept a sensor current of up to 50 mA
Data Source
AI summary
The disclosure relates to a sensor assembly for a vehicle, comprising a sensor element for detecting a measurement variable and at least two control devices, each having a measuring circuit and a power source. A first connection of the sensor element is connected to the power source of a first control device. A second connection of the sensor element is connected to a ground connection via a measuring circuit of a second control device. The measuring circuit of the first control device evaluates sensor current detected in a high side path of the sensor element. The measuring circuit of the second control device evaluates sensor current detected in a low side path of the sensor element. A first emergency protective circuit provides an alternative low side path for the sensor element and receives the sensor current if the voltage drop reaches a predefined breakover voltage value.