SU1002860A1 - Internal combustion engine indicating device - Google Patents

Description

(54) DEVICE FOR INDICATING INTERNAL COMBUSTION ENGINES

The invention relates to a measuring technique, namely, to ectrometric devices for indirirovanie internal combustion engines.

A device for indirirovanie heat engines of internal combustion, which contains an electronic device, a recording device made in the form of a drum with special paper wound around it, a mechanical switch, and the recording device is mechanically connected to the crankshaft of the engine 1.

A disadvantage of the known device is the complexity of processing indsh: the atom diagram due to the large instability of the working process. In addition, a high vibrass recorder is characterized by low reliability.

It is also known a device for measuring dantuni in an engine cylinder, containing a capacitive sensor, an electric converter and a recording device.

Through a capacitive sensor and an electric converter, the pressure in the combustion chamber is converted into an electrical signal, which is recorded by a recording device.

five . The device is characterized by high sensitivity, as well as by the fact that it is possible to remove the pressure indicator up to ten meters from the point where the sensor is turned on without significant loss of sensation.

10 values of C 2.

A significant drawback of the device is the low measurement accuracy due to the fact that the capacitive transducer is temperature sensitive.

15

The closest to the proposed technical essence and the achieved effect is a device that contains a pressure sensor, made in the form of a piezoelectric transducer with a large-scale capacitance connected in parallel to the sensor, an electrometric amplifier, a mechanical switch 3i button connected in parallel to the large-scale capacitance and a registering device CS Disadvantages of the device The accuracy and inconvenience of measurements are low. When measuring the pressure in the engine compartment of the engine, the electrical signal of the sensor, proportional to the magnitude of the laziness, is amplified by an electrometric amplifier and recorded by an electron oscilloscope. It is known that when using pressure sensors with a piezoelectric effect to measure pressure fluctuations, an image of the pressure-curved image is observed on the screen of an optical ray tube in the measurement process. The speed of displacement mainly depends on the time constant of the electrometric amplifier and the resistances of the insulation of the sensor and the connecting line. The displacement of the pressure curve is due to the fact that the static charge of the grid of the metric cascade occurs during pressure measurement, which leads to the appearance of a static potential on the capacitance capacitor connected in parallel with the sensor. At the same time, the working point of the electrometric amplifier is shifted and, consequently, the image of the pressure curve on the screen of the oscilloscope tube is mixed. Before measurement, the operator presses the button, thereby discharging the scale capacitance to zero potential and returns the operating point of the electrometric amplifier to the optimum position. When operating the device, the following is characteristic: Constantly distracts the attention of the operator from the main measurement due to the need to manipulate the button. At each measurement, it is necessary to press the button at least five times even in the case of good isolation of the connecting line. The electrometric amplifier, sensor AND connect the line must meet the following technical characteristics: the time constant of the amplifier is no less than 10 °; resistance isolator sensor and connecting line no less. The aim of the invention is to improve the accuracy and convenience of measurement. The goal is achieved by those. WHAT IN THE ENGINE INDICATOR

Leu of the innermost} slurani, including a pressure sensor, made in the form of a piezoelectric converter with

the first differential diode circuit 9 and the first diode limit 4, which are made in series with one another, the electric booster, the mechanical switch button and the registering device, have an electronic switch, an amplifier-limiter and a delay circuit made in the form of a series-connected differential circuit, diode limiter, waiting multivibrator, the second differential; the electronic circuit and the second diode limiter, and the electronic key is connected in parallel with the mechanical switch, and its control input is connected via a delay circuit to the output of the output of the body — the limiter, whose input is connected to the output of the electrometric amplifier. Such an embodiment of the proposed device provides a periodic discharge of the scale capacitance to zero potential, as a result, the working point of the electrometric amplifier is returned after each engine operating cycle, using the measured signal itself, converted accordingly. Since the return of the operating point of the electrometric amplifier will be made at short intervals (about 8.5 Hz at h 1000 rpm), the image of the pressure curve on the electronic oscilloscope will not shift even with less stringent requirements for the electrometric amplifier. and the connecting line, as well as the temperature and humidity of the surrounding air .. FIG. 1 shows a block diagram of the proposed device; in fig. Part 2 of the block diagram with the corresponding blocks and time diagrams of the conversion v of the snake of the 8Moh signal. The device contains a sensor 1, made in the form of a piezoelectric transducer, large-scale capacitance 2, electrometric amplifier 3, mechanical switch-button 4, connected in parallel with large-scale capacitance 2, electronic oscilloscope 5, electronic switch 6 connected to the output of electrometric amplifier, connected in parallel with the contacts of the mechanical switch 4, the limiting amplifier 7, the input of which is connected to the output of the electrometric amplifier 3, and the output is connected to the control input of the electronic switch 6 through tion of the delay circuit 8,

wichtel 10, the waiting multivibrator 11, the second differentiating circuit 12 in the second diode limiter 13.

The device works as follows.

An electric charge proportional to the measurement of pressure in the engine combustion chamber, which occurs on sensor 1, leads to the appearance of) on the base container 2, and therefore on the electrometric amplifier 3 of the electric signal (diagram a of Fig. 2). Reinforced by an electrometric amplifier 3, this signal is fed to an electronic oscilloscope 5 and to the input of the amplifier-limiter 7. The signal amplified and limited by an amplifier-limiter 7, and having an almost rectangular shape (plot b of Fig. 2) is fed to the input of the delay circuit 8, where the differentiating circuit 9 is transformed into two oppositely short pulses corresponding in time to the leading and falling edges of the signal of the amplifier-limiter 7 (the diagram in Fig. 2). A pulse corresponding to the trailing edge through the diode limiter 10 (plot g of Fig. 2) is triggered by a blown-down multivibrator 11, which outputs a rectangular pulse at the output (plot d of Fig. 2). The pulse duration of the standby multivibrator 11 can be varied. Then the rectangular impulse of the multivibrator 11 is transformed by the second differentiating circuit 12. In this case, two different-polarized short pulses are also produced (plot e of Fig. 2), corresponding in time to the anterior and posterior rectangular pulses of the multivibrator 11. The impulse corresponding to the leading front is cut off by the second diode the limiter 13, namely, the pulse corresponding to the rear (|) ontu (diagram of Fig. 2), enters the control input of the electronic switch 6, which short-circuits the contacts of the switch button 4 on em pulse effect. In this case, the large-scale capacitance 2 is discharged to zero potential, as a result of which the operating point of the electrometric amplifier 3 returns to the nominal position.

The cycle is repeated after each power stroke of the engine. The start of the operation of the electronic key 6 can be moved in time relative to the working volume of the drive, the pulse width of the waiting multivibrator, which ensures the operability of the proposed device at various CKt engine growth modes.

The use of a device for the inspection of internal combustion engines will increase the accuracy of measurement, imply less requirements for an elec- trograph amplifier and sensor insulation resistance and a connecting LIBIUM and, in addition, increase productivity in the internal combustion engines.

Claims (3)

1. Electropneumatic strobe indicator MAI-2. Instructions. M., 1956. 2. Kartov RG Electronics in the testing of heat engines. M., 1963, with. 19-31. 3. Karpov RG Electronics in the test “Research Institute of Heat Engines. M., 1963, with. 37 (prototype). P (t) 1