초록 ▼

In order to eliminate from an ion current sensor signals which are not derived from knocking of an engine, the ion current sensor signal is evaluated by a high-pass - low-pass filter to filter out signals of frequencies extraneous to knocking frequencies, using, preferably, a digital filter includin

In order to eliminate from an ion current sensor signals which are not derived from knocking of an engine, the ion current sensor signal is evaluated by a high-pass - low-pass filter to filter out signals of frequencies extraneous to knocking frequencies, using, preferably, a digital filter including two timing stages (11, 13) connected to a counter; to inhibit response of the circuit, an interrupter switch (8) is included in the evaluation circuit, which is opened upon sensing of disturbance signals due to ignition events, for example upon occurrence of ignition, by setting a timing stage (20) which maintains the switch open, and thus inhibits evaluation of oscillatory signals from the ion current sensor (1) for the timing duration thereof. To store previously counted oscillatory signals, a further timing stage (21) can be provided, likewise connected to the ignition signal and enabled at the initiation of current flow through the primary of an ignition coil to prevent resetting of the counter for the timing duration thereof.

대표청구항 ▼

In combination with an internal combustion engine, a knock sensing system having an ion current sensor (1) located in a combustion chamber of the engine and providing an ion current signal upon sensing occurrence of combustion in the chamber; means (2, 3, 4) supplying an energizing voltage to the io

In combination with an internal combustion engine, a knock sensing system having an ion current sensor (1) located in a combustion chamber of the engine and providing an ion current signal upon sensing occurrence of combustion in the chamber; means (2, 3, 4) supplying an energizing voltage to the ion current sensor; an evaluation circuit means connected to the ion current sensor for evaluating and analyzing the ion current supplied by the sensor, and comprising means coupled to the internal combustion engine responsive to engine operation which results in disturbance signals in the current sensor, for providing disturbance control output signals; and interruption means connected in said evaluation circuit means inhibiting analysis and evaluation in said evaluation circuit means of the signals from the sensor upon sensing of disturbance signals in the ion current signal.