Vehicle engine operation
First Claim
1. A system for detecting an operating state of a vehicle engine, the system comprising:
- an input configured to couple in a signal from a power line of a vehicle engine;
a low-pass filter configured to filter the signal received from the power line to remove transient noise components of the signal which exceed 1 kHz, the transient noise components being induced on the power line by signalling activity on a control area network of the vehicle;
a first detector configured to receive the filtered signal and detect when transient noise in the filtered signal rises above a first voltage threshold, the first voltage threshold being set at a voltage level that is lower than the voltage level of transient noise associated with operation of a high current electrical ignition system for starting the vehicle engine, and generate a first detection signal in response thereto;
a second detector configured to receive the filtered signal and detect when the transient noise in the filtered signal falls below a second voltage threshold, which is lower than the first voltage threshold and indicates that the engine has been switched off, and generate a second detection signal in response thereto; and
a circuit configured to generate a first output signal in response to the first detection signal and a second output signal in response to the second detection signal.
3 Assignments
0 Petitions
Accused Products
Abstract
Disclosed is a system for detecting an operating state of a vehicle engine, for example, in order to arm or disarm a vehicle alarm system. The system comprises: an input coupled to a power line of a vehicle; means to filter out relatively high frequency transient noise components of a signal received from the power line; a first detector for receiving the filtered signal and detecting when transient noise associated with the power line rises above a first threshold and generating a first detection signal in response thereto; a second detector for receiving the filtered signal and detecting when the transient noise falls below a second threshold, which is lower than the first threshold, and generating a second detection signal in response thereto; and means for generating a first output signal in response to the first detection signal and a second output signal in response to the second detection signal.
31 Citations
11 Claims
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1. A system for detecting an operating state of a vehicle engine, the system comprising:
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an input configured to couple in a signal from a power line of a vehicle engine; a low-pass filter configured to filter the signal received from the power line to remove transient noise components of the signal which exceed 1 kHz, the transient noise components being induced on the power line by signalling activity on a control area network of the vehicle; a first detector configured to receive the filtered signal and detect when transient noise in the filtered signal rises above a first voltage threshold, the first voltage threshold being set at a voltage level that is lower than the voltage level of transient noise associated with operation of a high current electrical ignition system for starting the vehicle engine, and generate a first detection signal in response thereto; a second detector configured to receive the filtered signal and detect when the transient noise in the filtered signal falls below a second voltage threshold, which is lower than the first voltage threshold and indicates that the engine has been switched off, and generate a second detection signal in response thereto; and a circuit configured to generate a first output signal in response to the first detection signal and a second output signal in response to the second detection signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A security system for a vehicle comprising:
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an input configured to couple in a signal from a power line of a vehicle engine; a low-pass filter configured to filter the signal received from the power line to remove transient noise components of the signal which exceed 1 KHz, the transient noise components being induced on the power line by signaling activity on a control area network of the vehicle; a first detector configured to receive the filtered signal and detect when transient noise in the filtered signal rises above a first voltage threshold, the first voltage threshold being set at a voltage level that is lower than the voltage level of transient noise associated with operation of a high current electrical ignition system for starting the vehicle engine, and generate a first detection signal in response thereto; a second detector configured to receive the filtered signal and detect when the transient noise in the filtered signal falls below a second voltage threshold, which is lower than the first voltage threshold and indicates that the engine has been switched off, and generate a second detection signal in response thereto; and a circuit configured to generate a first output signal in response to the first detection signal and a second output signal in response to the second detection signal; wherein the security system is configured to disarm on the basis of the first output signal and to arm on the basis of the second output signal. - View Dependent Claims (9, 10)
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11. A non-transitory computer-readable storage medium comprising computer-executable instructions which, when executed by a processor, cause a computing device to perform a method of detecting an operating state of a vehicle engine, the method comprising:
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receiving a signal from a power line of a vehicle engine; filtering the signal received from the power line to remove transient noise components of the signal which exceed 1 kHz, the transient noise components being induced on the power line by signalling activity on a control area network of the vehicle; detecting when transient noise in the filtered signal rises above a first voltage threshold, the first voltage threshold being set at a voltage level that is lower than the voltage level of transient noise associated with operation of a high current electrical ignition system for starting the vehicle engine, and generating a first detection signal in response thereto; detecting when the transient noise in the filtered signal falls below a second voltage threshold, which is lower than the first voltage threshold and indicates that the engine has been switched off, and generating a second detection signal in response thereto; and generating a first output signal in response to the first detection signal and a second output signal in response to the second detection signal.
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Specification