RU32275U1 - Device for detecting detonation in an internal combustion engine - Google Patents

Description

The proposed utility model is aimed at solving the problem of increasing the reliability and reliability of detecting detonation in an internal combustion engine and in simplifying a device for detecting detonation in an internal combustion engine.

This problem is solved in that in a device for detecting detonation in an internal combustion engine, comprising a knock sensor, an amplifier, a bandpass filter, a half-wave rectification unit for electric signals, a device for determining the integral value of the rectified electric signals, a unit for calculating a vibration signal parameter and evaluating the presence of detonation , the block of half-wave rectification of electrical signals contains a first capacitor, the first output of which is connected to a strip iltrom, and the second with the first output of the first resistor, the second output of which is connected to the first input of the diode bridge and to the inverting input of the operational amplifier, the output of which is connected to the second input of the diode bridge and through the second resistor to the first output of the first resistor, and the device for determining the integral the magnitude of the rectified electrical signals is made in the form of an integrating capacitor installed parallel to the outputs of the half-wave rectification unit of the electrical signal, the outputs of which are connected are coupled to a comparator, the output of which is connected to the first input of the current pulse shaper, to the second input of which a clock signal source is connected, and the output of the pulse shaper. current is connected to the input of the dosing device and to the unit for calculating the parameter of the vibration signal and evaluating the presence of detonation, and the outputs of the dosing device are connected to the terminals of the integrating capacitor.

The implementation of the half-wave rectification block of electrical signals containing the first capacitor, the first output of which is connected to a bandpass filter, and the second to the first output of the first resistor, the second output of which is connected to the first input of the diode bridge and to the inverting input of the operational amplifier, the output of which is connected to the second input of the diode bridge and through the second resistor to the first output of the first resistor, improves the reliability and reliability of the detection of detonation in an internal combustion engine due to the fact that the presence of the first capacitor provides separation

useful signal from the constant and low-frequency component, the first resistor allows you to set the optimal current conversion coefficient, the second resistor installed in the feedback line of the operational amplifier, minimizes the output bias of the operational amplifier to reduce distortion when rectifying small amplitude signals.

The implementation in the proposed technical solution of a device for determining the integrated value of rectified electrical signals in the form of an integrating capacitor installed parallel to the outputs of the half-wave rectification unit of electrical signals, the outputs of which are connected to a comparator, the output of which is connected to the first input of the current pulse shaper, to the second input of which a signal source is connected clock frequency, and the output of the current pulse shaper is connected to the input of the dosing device in addition to the unit for calculating the parameter of the vibration signal and evaluating the presence of detonation, and the outputs of the metering device are connected to the terminals of the integrating capacitor, which improves the accuracy of detecting detonation in the internal combustion engine due to the possibility of accurate integration of the rectified electric signals with the help of an integrating capacitor in a wide amplitude range of these signals, which takes place during operation of an internal combustion engine, as well as small relative levels of intrinsic noise and comm Discount interference due to the lack of hardware strobe, due to the aforementioned one for the elements included in the device. The simplification of the device for detecting detonation in an internal combustion engine is generally achieved through the implementation of a device for determining the integral value of rectified electrical signals based on simple and reliable circuitry with the possibility of eliminating an analog-digital converter.

Figure 1 presents a diagram of the proposed device for detecting detonation in an internal combustion engine, and figure 2 is a block diagram of a half-wave rectification of electrical signals.

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for example, on the walls of the cylinder block, amplifier 2, band-pass filter 3, block 4 half-wave rectification of electrical signals, which can be performed on an operational amplifier with a diode bridge (see figure 2). In parallel with the outputs of unit 4 of the half-wave rectification of electrical signals, an integrating capacitor 5 is installed, the outputs of which are connected to a comparator 6, the output of which is connected to the first input of the current pulse shaper 7, to the second input of which a clock signal source 8 is connected (a clock source can be used microprocessor suitable frequency output). The output of the shaper 7 of the current pulses is connected to the input of the metering device 9 and to the block 10 for calculating the parameter of the vibration signal and assess the presence of detonation, and the outputs of the metering device 9 are connected to the terminals of the integrating capacitor 5.

As a current pulse shaper 7, for example, a K-MOS D-flip-flop fast-acting of any company or a Phillips microcircuit 74AHC74PW can be used.

As the metering device 9, for example, resistive-diode circuits can be used, connected on the one hand to the outputs of the D-flip-flop, or contacts 8 and 9 of the 74AHC74PW chip, and on the other hand, to the conclusions of the integrating capacitor 5, controlled current sources or a switched capacitor with analog keys.

The unit 10 for calculating the parameter of the vibration signal and evaluating the presence of detonation (a microprocessor in which there is a counting input of the number of pulses) operates with the integral values of the rectified electric signals already received before it (taking into account the conversion of the number of pulses into the value of the integral) and its specific implementation depends on a specific parameter on the basis of which an assessment is made of the presence of detonation, and an algorithm for such an assessment, and, accordingly, can be implemented in a similar way, as, for example, in the described above known technical solutions.

Block 4 of the half-wave rectification of electrical signals (figure 2) is made containing the first capacitor 11, the first output of which is connected to a band-pass filter 3, and the second to the first output of the first resistor 12, the second

the output of which is connected to the first input of the diode bridge 13 and to the inverting input of the operational amplifier 14, the output of which is connected to the second input of the diode bridge 13 and through the second resistor 15 to the first output of the first resistor 12.

The proposed device for detecting detonation in an internal combustion engine operates as follows.

In a predetermined time interval of the duty cycle of the internal combustion engine, vibration signals caused by the combustion process of the air-fuel mixture are measured using a detonation sensor 1, for example, of the piezoelectric type, which are converted into an electrical signal (electrical voltage) at its output. These electrical signals, in the same way as in the prototype, are amplified by an amplifier 2, filtered by a band-pass filter 3, and fed to the input of a half-wave rectification unit 4 of electric signals, in which through the first capacitor 11, which separates the useful signal from the constant and low-frequency components, through the first resistor 12, which sets the current conversion coefficient, inverts the input of the operational amplifier, the operational amplifier 14, the diode bridge 13 are connected to the conclusions I integrate its capacitor 5 and charge it with current 1. where Uf is the voltage value of the electrical signal at the output of unit 4 of the half-wave rectification of electrical signals, / f is the resistance at the input of this unit, which is mainly determined by the resistance of the first resistor 12, while the second resistor 15 minimizes the output bias of the operational amplifier 14 to reduce distortion during rectification of small amplitude signals. In this case, the voltage value at the integrating capacitor 5 increases and, accordingly, the voltage value at the input to the comparator 6 increases. When this voltage exceeds the threshold value of the voltage value of the comparator 6, the latter generates a signal (logic level) to the current pulse shaper 7, which, in in accordance with the clock frequency of the clock source 8, generates a signal to the metering device 9, causing the formation of a current pulse supplied to the integrating capacitor 5, and reduce ayuschegonapryazhenienanemnaodindiskret

{(Щ

 where / is the magnitude of the current in the pulse, 2 is the duration of the current pulse,

 at

f capacitance of the integrating capacitor. At the same time, the current pulse shaper 7 also provides a signal supplied to the external counting input of the vibration parameter parameter calculating unit 10 and detonation assessment.

With a further (after receipt of the current pulse from the metering device 9) increase in the voltage value at the integrating capacitor 5, due to the corresponding amplitude of the electric signal after block 4 of the half-wave rectification of electric signals, and exceeding this value of the threshold value of the comparator 6, the latter, in the same way as described above , gives a signal to generate the next current pulse and the counting input of the block 10 calculates the parameter of the vibration signal and estimates the presence of detonation.

If, in accordance with the clock frequency at the time of the formation of the next pulse, the voltage on the integrating capacitor 5 did not manage to exceed the threshold value of the comparator 6, the latter does not give a signal to the shaper 7 of the current pulses and the counting input of the unit 10 for detecting the vibration parameter and evaluating the presence of detonation and accordingly, a current pulse is not formed, that is, it is not supplied to the integrating capacitor.

Thus, the larger the amplitude of the electric signal coming from the output of unit 4 of the half-wave rectification of electric signals for the same period of time, and, accordingly, the larger the integral value of this signal, the faster the voltage at the integrating capacitor 5 increases and the greater the number of pulses current should be supplied to the integrating capacitor 5 to compensate for the increase in voltage across it.

In accordance with the above, we can consider

//

JIi ,, t .Hu / 24.,/ f - C /.

where c is the number of pulses.

The value of the number of pulses obtained as a result of the operations described above, carried out using the appropriate circuitry, is fed to the counting input of the block 10 for calculating the parameter of the vibration signal and evaluating the presence of detonation, in which the integral value of the rectified electric signals is used to determine any

Dd) // y

a specific parameter of the vibration signal and estimates based on it the presence of detonation in the internal combustion engine, which is not the subject of the proposed technical solution.

Thus, the proposed utility model allows with high reliability and reliability to detect the presence of detonation in an internal combustion engine using simple and reliable circuitry.

Claims (1)

A device for detecting detonation in an internal combustion engine, comprising a knock sensor, an amplifier, a bandpass filter, a half-wave rectification unit for electrical signals, a device for determining the integral value of the rectified electric signals, a unit for calculating a vibration signal parameter and evaluating the presence of detonation, characterized in that the half-wave block rectification of electrical signals contains a first capacitor, the first output of which is connected to a band-pass filter, and in the second - with the first output of the first resistor, the second output of which is connected to the first input of the diode bridge and to the inverting input of the operational amplifier, the output of which is connected to the second input of the diode bridge and through the second resistor to the first output of the first resistor, and a device for determining the integral value of the rectified electric The signal is made in the form of an integrating capacitor installed parallel to the outputs of the half-wave rectification unit of the electrical signal, the terminals of which are connected to a parator, the output of which is connected to the first input of the current pulse shaper, to the second input of which a clock signal source is connected, the output of the current pulse shaper is connected to the input of the dosing device and to the unit for calculating the vibration signal parameter and evaluating the presence of detonation, and the outputs of the dosing device are connected to the conclusions integrating capacitor.