Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
199 words
An apparatus for detecting undesirable combustion characteristics in the combustion process in a spark-ignited internal combustion engine and discriminating those characteristics from disturbances having similar characteristics which do not originate in the combustion process, the apparatus comprising sensor means for sensing solid borne signals and for providing a knocking frequency output signal in response thereto, band-pass filter means tuned to the frequency of an engine knocking vibration, wherein the output signal of the sensor means is fed to the band-pass filter means resulting in a knocking frequency signal, and band-blocking filter means for surpressing frequencies below a predetermined knocking vibration frequency lower than the knocking vibration frequency and frequencies above a predetermined knocking vibration frequency higher than the knocking vibration frequency, rotational speed evaluation means for evaluating an output signal from the band-blocking filter means, r.m.s. rectifier means arranged in series with the band-blocking filter means and evaluation means for forming a reference knock signal, comparator means for comparing the reference knock signal with the knocking frequency signal, and timer means responsive to the comparator means for supplying an output pulse of a predetermined duration when the comparator means senses the knocking frequency signal exceeds the reference knock signal.
Claim 2
Independent Claim
199 words
An apparatus for detecting undesirable combustion characteristics in the combustion process in a spark-ignited internal combustion engine and discriminating those characteristics from disturbances having similar characteristics which do not originate in the combustion process, the apparatus comprising sensor means for sensing solid borne signals and for providing a knocking frequency output signal in response thereto, band-pass filter means tuned to the frequency of an engine knocking vibration, wherein the output signal of the sensor means is fed to the band-pass filter means resulting in a knocking frequency signal, and band-blocking filter means for surpressing frequencies below a predetermined knocking vibration frequency lower than the knocking vibration frequency and frequencies above a predetermined knocking vibration frequency higher than the knocking vibration frequency, rotational speed evaluation means for evaluating an output signal from the band-blocking filter means, r.m.s. rectifier means arranged in series with the band-blocking filter means and evaluation means for forming a reference knock signal, comparator means for comparing the reference knock signal with the knocking frequency signal, and timer means responsive to the comparator means for supplying an output pulse of a predetermined duration when the comparator means senses the knocking frequency signal exceeds the reference knock signal.
Claim 3
Dependent Claim
15 words
An apparatus according to claim 1, wherein the timer means is a monostable flip flop.
Claim 4
Dependent Claim
44 words
An apparatus according to claim 2, wherein the evaluation means is a monostable timer means controllable by an ignition signal from an ignition system of the engine for short-circuiting an input to the r.m.s. rectifier means for a predetermined time period after each ignition.
Claim 5
Independent Claim
36 words
An apparatus according to claims 1, 2, or 3, wherein an amplifier means is provided for amplifying the reference knock signal of the r.m.s. rectifier means and for providing an output signal to the comparator means.
Claim 6
Dependent Claim
51 words
An apparatus according to claim 4, wherein an input amplifier means is disposed between the sensor means and the band-pass filter means and band-blocking filter means for amplifying the output signal of the sensor means prior to an output signal being fed to the band-pass filter means and band-blocking filter means.
Claim 7
Dependent Claim
20 words
An apparatus according to claim 4, wherein the evaluation means is adapted to influence an amplification of the amplifier means.
Claim 8
Dependent Claim
59 words
An apparatus according to claim 3, wherein an amplifier means is provided for amplifying the reference knock signal of the r.m.s. rectifier means and for providing an output signal to the comparator means, and in that evaluation means includes an engine ignition means for providing a rotational speed control signal to the amplifier means to change an amplification thereof.