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 output a filtered signal by filtering the signal received from the power line to remove transient noise components of the signal which exceed a cut-off frequency, the cut-off frequency being selected to remove transient noise components 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 which indicates 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 transient noise in the filtered signal falls below a second voltage threshold, which is lower than the first voltage threshold, and indicates that the vehicle 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.
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Accused Products
Abstract
Disclosed is a system for detecting an operating state of a vehicle engine. 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.
28 Citations
19 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 output a filtered signal by filtering the signal received from the power line to remove transient noise components of the signal which exceed a cut-off frequency, the cut-off frequency being selected to remove transient noise components 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 which indicates 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 transient noise in the filtered signal falls below a second voltage threshold, which is lower than the first voltage threshold, and indicates that the vehicle 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, 8)
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9. 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; a low-pass filter configured to output a filtered signal by filtering the signal received from the power line to remove transient noise components of the signal which exceed a cut-off frequency, cut-off frequency being selected to remove transient noise components 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 which indicates 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 receiving the filtered signal and detect when transient noise in the filtered signal falls below a second voltage threshold, which is lower than the first voltage threshold, and indicates that the vehicle 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 arm in response to the second output signal and to disarm in response to the first output signal. - View Dependent Claims (10, 11)
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12. A non-transitory computer-readable storage medium comprising computer-executable instructions which, when executed by a processor, cause a computing device to:
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output a filtered signal by filtering a signal received from a power line of a vehicle to remove transient noise components of the signal which exceed a cut-off frequency, cut-off frequency being selected to remove transient noise components induced on the power line by signalling activity on a control area network of the vehicle; detect when transient noise in the filtered signal rises above a first voltage threshold which indicates operation of a high current electrical ignition system for starting the vehicle engine, and generate a first detection signal in response thereto; detect when transient noise in the filtered signal falls below a second voltage threshold, which is lower than the first voltage threshold, and indicates that the vehicle engine has been switched off, and generate a second detection signal in response thereto; and 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 (13, 14, 15, 16, 17, 18, 19)
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Specification