PTC Controller Control Input as Error Output
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Solution Overview
Problem
Existing methods for testing the functionality of electrical heating devices in motor vehicles, particularly those with PTC elements, are inadequate as they require integration into the vehicle's bus system and lack efficient error signaling for malfunctions like short circuits, open loads, and excess temperature.
Innovation Solution
A method where the control input of the PTC controller doubles as an error output, grounding in case of malfunction, allowing direct error detection without additional output signals, and using pulse width modulation to communicate the type of error, enabling diagnosis without bus system integration and providing actionable feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the control input is used as an error output by grounding in case of malfunction, then the device complexity is reduced and bus system integration is avoided, but the ability to communicate detailed error types is limited
Solution Approach 1:
The control input of the PTC controller is designed to serve dual functions: it acts as a control signal input during normal operation and as an error output during malfunctions. When an error occurs, the controller grounds this multi-functional input, allowing error detection without requiring a separate dedicated error output line. This eliminates the need for additional wiring and integration into the vehicle's bus system, directly reducing device complexity while maintaining error detection capability.
2Loss of information
If pulse width modulation is used to communicate error types through the control input, then error type information is transmitted, but the ease of operation and interpretation is reduced
Solution Approach 1:
The system implements feedback by modulating the control input signal with pulse width modulation (PWM) when an error occurs. The PWM duty cycle encodes specific error types, allowing the diagnostic device to receive and interpret detailed error information through the existing control input line. This feedback mechanism enables comprehensive error communication without adding physical complexity, as the same control line carries both control commands and diagnostic information in different operational states.
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 efficient and cost-effective functional testing of electrical heating devices by allowing direct error detection and communication of error types, facilitating immediate corrective actions without requiring bus system integration, thus improving reliability and simplicity.
Implementation Method 1
at least one PTC element which—controlled by a PTC controller—generates heat when voltage is applied as a result of a current flow
Implementation Method 2
the control input at the same time forms an error output that the PTC controller draws to ground in the event of a malfunction
Data Source
Figure 1
Figure 2~4
AI summary
The method for function testing of an electric heating device, especially a PTC-heater (10), for a motor vehicle, in which an operating device produces a control signal at a control input of a PTC-controller (1), is carried out in such a way that the control input simultaneously forms an error output which the PTC-controller discharges to earth in the case of a malfunction. In the case of a malfunction, no return signal is transmitted over the error output. An independent claim is included for an electric heating device, especially a PTC-heater for a motor vehicle.