SU1553871A1 - Apparatus for determining top dead center of i.c.engine - Google Patents

Abstract

This invention relates to an instrumentation technique for diagnosing an internal combustion engine (ICE). The signal from inductive sensor 1 is fed to the input of the amplifier-limiter 3 offset from its maximum amplitude when passing the top dead center mark (TDC), applied, for example, on a rotating engine flywheel. The comparator 4 generates pulses at the "tops" of the TDC mark pulses, through which trigger 7 is inserted. When the unbiased signal of the inductive sensor 1 passes through a zero threshold level according to the signal from comparator 6, trigger 7 is reset, thereby forming a TDC time stamp. Interference occurring in the output signal of inductive sensor 1, while falling into the limiting zone of the amplifier - limiter 3 and does not lead to false positives of the device. 1 hp f-ly, 2 ill.

Description

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The invention relates to instrumentation engineering and can be used, for example, in electronic diagnostic devices to control the operation of internal combustion engines.

The purpose of the invention is to simplify and increase reliability by increasing the noise immunity.

FIG. 1 shows a circuit diagram of the device; in fig. 2 - timing charts of the device.

The device contains an inductive sensor 1, a block 2 bindings, the first 3 and second 4 amplifiers-limiters, the first 5 and second 6 comparators, RS-trigger 7 and the output bus 8. Block 2 bindings contains a capacitor 9 and connected to it in parallel a diode 10 and a resistor 11, the capacitor terminals being the terminals of the anchor block 2. Inductive sensor 1 is connected via a series of 2 locking units, the first amplifier-limiter 3 and the first comparator are connected to the S-input of the RS flip-flop 7 "and to the R-input - through the second connected amplifier of the limiting device 4 and a closed comparator. Diode Yu and resistor 11 are connected in parallel to the input of the first amplifier-limiter 3. The output of RS-trigger 7 is connected to the output bus.

The device works as follows.

The signal corresponding to the position of the piston at the top dead center (TDC) (and removed from the output of the inductive sensor 1 (Fig. 2a) is fed to the input of the amplifier-limiter 3 offset from the maximum amplitude that occurs when the piston passes TDC past the inductive sensor 1 (FIG. 26). The comparator 5 in this case generates pulses along the tops of the TDC-mark pulses (Fig. 2c), which leads to the triggering of the RS flip-flop 7 (Fig. 2 #.

The comparator 6 generates pulses at the transitions of the unbiased signal of the inductive sensor removed from the output t, through the zero line oports. (Fig. 2d), thereby providing a reset of the RS flip-flop 7 at the moment when the piston passes the EMG mark past the inductive sensor t (Fig. 2e.

The falling edge of the signal entering the output bus 8 of the device, with

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This exactly corresponds to the mark Btlf piston engine.

Comparator 5 must have a threshold level of pickup Unop and Cr Cds, where U at - the level of reference of block 2 {CUs - gain gain of amplifier-limiter 3. Comparators 5 and 6 may have, for example, zero threshold levels.

By tying the formation of output signals to the tops of the TDC markers, high noise immunity of the device operation is provided, since minor interferences occurring in the output signal of inductive sensor 1 fall into the limiting zone of the amplifier-limiter 3 and do not arrive at the computer input. rator 5 and thus do not lead to false triggerings of trigger 7. This ensures high reliability of the device for detecting TDC in a wide dynamic frequency range of the engine crankshaft and makes it uncritical for installing, for example, inductive sensor 1 relative to a rotating flywheel. with TDC mark.

Claims (2)

1. Device for determining the top dead center of an internal combustion engine, comprising an inductive sensor, first and second comparators and an RS flip-flop, characterized in that, in order to simplify and increase reliability, the device further comprises an anchor block, the first and second limiting amplifiers, the output of the inductive sensor being connected to the S-input of the RS flip-flop via the first amplifier-limiter and the first comparator, and with the R-input of the RS-flip-flop through a serially connected second amplifier-limiter and the second comparator, and the output of the trigger is connected to the output bus. 2. Device pop. 1, characterized in that the anchor block comprises a capacitor, a diode and - a resistor, the input of the capacitor being the input of the binding, and the output of the capacitor, which is the output of the coupling module, is connected to the parallel connected by a diode and a resistor. Mr. JULLJ r ҐҐTJlJJirinJlJLfLiJ-UilL BUT r4BHT FIG. 2