Solenoid Valve Type Detection Circuit Using Constant Current Source
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Solution Overview
Problem
Existing anti-lock braking system (ABS) devices for utility vehicles cannot accurately identify solenoid valves installed with incorrect voltage ratings, leading to non-functional valves in 12 V systems and overload in 24 V systems, due to their inability to detect high-resistance loads effectively.
Innovation Solution
A circuit arrangement that determines the type of solenoid valve by measuring the resistance of its coils using a constant current source and current mirror circuit, allowing identification of the correct voltage range without activating the solenoid valve, and is integrated into existing control devices or modules for initialization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage feedback evaluation is used to monitor solenoid valve end states, then short circuits to ground and supply voltage can be detected, but high-resistance loads (incorrectly installed solenoid valves) cannot be reliably identified below very high resistance values
Solution Approach 1:
The patent replaces the conventional voltage feedback evaluation method with a current measurement method. Instead of monitoring voltage at the solenoid valve to detect faults, the system measures the actual current flowing through the coil. This substitution enables reliable detection of high-resistance loads (incorrectly installed solenoid valves) by comparing measured current against expected current values for correct voltage ratings, thereby resolving the limitation of detecting only very high resistance values.
2Adaptability or versatility
If solenoid valves with different coil resistances are used for 12 V and 24 V systems, then appropriate valve operation can be achieved, but incorrect installation leads to non-functional valves in 12 V systems or overload in 24 V systems
Solution Approach 1:
The patent implements a feedback mechanism where the actual current flowing through the solenoid valve coil is continuously measured and compared against expected current values. When a mismatch is detected (indicating incorrect voltage rating installation), the system provides feedback to the control device, which can then issue a fault message or prevent operation. This feedback loop prevents valve failure in 12 V systems and overload in 24 V systems by enabling early detection of incorrect installations.
3Ease of manufacture
If previous ABS control devices monitor only end states for short circuits and load interruptions, then basic fault protection is provided, but incorrectly installed solenoid valves with high resistance remain undetected
Solution Approach 1:
The patent changes the monitoring parameter from voltage feedback to current measurement. By measuring the actual current flowing through the solenoid valve coil and comparing it against expected current values for different voltage ratings, the system gains the ability to detect incorrectly installed solenoid valves. This parameter change maintains the simplicity of monitoring while significantly improving fault detection capability, as current measurement directly reflects the load condition and voltage compatibility.
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
Enables reliable identification of solenoid valve types within existing systems, preventing non-response or failure by distinguishing between 12 V and 24 V coils without affecting ABS system operations, and allows for detection of faulty installations or temperature changes.
Implementation Method 1
If a low measurement current is now impressed into each of the coils provided, the voltage resulting from this can be measured at the solenoid valve coil and evaluated via a microcontroller
Implementation Method 2
a current mirror circuit, which is arranged so as to generate a second voltage on a detection section of the circuit arrangement from a first voltage produced as a result of the impressed measurement current
Data Source
AI summary
A circuit arrangement for detecting a solenoid valve type in vehicles, including at least one solenoid valve in the circuit arrangement for detecting the solenoid valve type and having at least one coil winding having a resistance of the typical order of magnitude for a predetermined vehicle electrical distribution system supply voltage, a constant current source, arranged to impress a predetermined measurement current into the one coil winding of the solenoid valve, a current mirror circuit, arranged to generate a second voltage on a detection section of the circuit arrangement from a first voltage produced as a result of the impressed measurement current on the at least one coil winding of the at least one solenoid valve, in which the second voltage produced on the detection section is passed out, on the detection section, directly to a microcontroller in a control device for determining the type of solenoid valve.