SU553352A1 - Apparatus for determining the duration of fuel injection into an internal combustion engine - Google Patents

Description

(54) DEVICE FOR DETERMINING THE CONTINUOUS AND INPUT FUEL INJECTION OF THE ENGINE BffiTPEHHEFO

 HorjbicoKOi (u "rchchpp / pshsy okchoGshosgyyo ikdnKarofKj, no KOTOpiiM) iroichBodits definition of x x MoMcirroB. as well as cJiyfaiiuwNni optbkami operagor.

f Icjibjo p1b is the simplification and higher accuracy of the measurement process.

To achieve this goal, the output of the amplifier is connected in parallel with the signaling input of the injection channel, which is connected to the reference input, the device, the sample and memory connected to the reference unit, and the measurement interval generation unit, a pulse valve is connected between the reference unit and the valves. the record, a memory register is connected between the valves and the visual indication unit, and the output of the injection signal generator unit is connected to the control input of the interval generator unit and measuring, the output of which is coupled in parallel with the control inputs of sample and storage device and the valve device and the recording pulses are grappling.

The measuring interval shaping unit contains a low-pass filter connected to one input of the comparator through a sample and memory device, and the other directly, and a trigger, one input of which forms the control input of the measurement interval shaping unit and the other connected through the back front driver to the output a comparago that is also connected to the control input of the sampling and memory device, and the trigger output forms the output of the measuring interval shaping unit, the signal input of which forms the input Filtering lowpass.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 - voltage pins at the outputs of individual units of the device.

The device contains a pressure sensor I, for example, of the piezoelectric type, embedded in the high pressure fuel line before the injector and connected via an amplifier 2 signals of the pressure sensor to the injection start signal generation unit 3, which consists of the threshold device 4, executed, for example, according to a trigger circuit Schmitt, connected via a single vibrator 5 in parallel with the circuit of the extremum extraction unit 6 and the extraction circuit of the first pulse, also connected to each other. The input of block 6 is connected to the input of block 4 and serves as a signal input of block 3, and the output of circuit 7 is output of block 3. At the output of amplifier 2, a memory device 8 is connected in series, a comparison block 9, a write pulse valve 10, and block 9 is connected by another input to the input of the device 8. The output of the amplifier 2 is connected to the measuring interval forming unit 11, which is shown as a series-connected low-pass filter 12 of the sampling and storage device 13, the comparator 14, the back side of the pulse former and the rigger 16, another

the input of which is CBHsati with the output of block 3, is the control of the input of block P, and the output of CfXiwneii with control inputs of the device 8 and the valve 10. The output of the comparator 14 is also connected to another input of the device 13, and the other input of the comparator 14 together with the input of the filter 12 forms the signal input of the block 11. The generator 1 pulses of a fixed frequency in series through the counter 18, valves 19 and the memory register 20 is connected to the block 21 of the visual INDIKRTSIN, at the input of which the control device 22 is connected, also connected to the output of the trigger 16 The valve is operated and is connected to another input of the valves 19, and the other input of the counter 18 is connected to the output of the unit 3.

The low pass filter 12 is constant. time, which is chosen, based on the inequalities:

.

P) P2),

where T and TV are the period of the following and the duration of the injection pulses, respectively;

Trp is the time constant of a circuit consisting of device 13 and comparator 14.

The principle of operation of the device is to automatically detect the characteristic points of the pressure curve at the start and end points of the injection, followed by measuring the time interval between these moments. The moment of the start of fuel injection is determined by the moment of the occurrence of the first extremum (time tj on the seal and Fig. 2) on the leading front of the increasing injection pressure. The moment of the end of the injection (the moment ts on the plug in Fig. 2) is determined at the falling edge of the falling injection pressure at the moment of equality of the current pressure and the level of the start of the injection UB (with the proportionality coefficient, 75-1) recorded at the moment of the start of the injection. Since the injection process may cause pressure fluctuations relative to the level UB, and the current pressure value may be less than the value of UB, an additional feature is used to determine the true portion of the pressure drop caused by the fuel cut-off at the end of its supply. As the latter, the fact of reaching or intersecting is used (the moment tg on the chart in Fig. 2) by the falling pressure of the steady-state pressure signal Uy recorded at the moment of the start of the fuel supply (the moment ti on the chart in Fig. 2) o

Claims (3)

The moment of the start of injection is determined by the block 3, the formation of the signal of the start of injection. Sampling and memorizing device 8 fixes the signal UB proportional to the level UB, and comparison unit 9 generates pulses at the moment of equality of the decreasing pressure signal and level UB- The fact that the current value of the pressure signal Uy reaches or intersects is measured by the measurement interval shaping unit 11. The measurement of the fuel injection duration is carried out by the numerical impulse method. In the measurement process, the current injection time code te is recorded in the counter 18 with a reference point at the moment of the start of the injection (plot point a1; Fig. 2). At the time of the end of the injection (the moment ts on the plot of Fig. 2), the counter code 18 counts the signal of the comparison unit 9 and then transmits it to the visual indication unit 21. The signals of pressure sensor 1, which follow with period T, amplified by amplifier 2, are fed to the signal inputs of the block 3 forming the injection start signal of the comparison block 9, the measuring interval shaping block 11 and the signal input of the sampling and memorizing device 8. The pulses from the output of the generator 17 are fed to the input of the counter 18. Before the fuel supply starts, when the inequality (1) is fulfilled, the signal at the output of the low-pass filter 12 of the block 11 is almost equal to the signal Uy at the output of the amplifier 2 corresponding to the steady-state pressure level of the fuel before injection. As a result, the signals at both inputs of the comparator 14 are equal and, accordingly, the signal at the output of the comparator 14 is equal to or close to zero. Starting from the moment of supplying the fuel 11, the signal at the input of the comparator 14 connected to the output of amplifier 2 directly increases and becomes greater in magnitude of the signal at the other input of the comparator 14 connected to the output of the sampling and memorizing device 13. The comparator 14 triggers and generates the output signal 1 (plot b in Fig. 2) by which the output of the device 13 is sampled and stored due to the fulfillment of inequality 2, the level Uy is fixed (plot and fig. 2) with a further increase in the pressure signal, the output signal of the comparator 14 does not change. When the rising edge of the rising pressure reaches the injection level Ug, the injection start signal formation unit UB, the injection start signal formation block 3, generates a pulse of a fixed duration (plot in Fig. 2), the leading front of which corresponds to the moment of the fuel injection start. The injection start momentum enters the installation input of sensor 1. By this pulse, the counter 18 is set to the zero state, as a result of which, as it is filled with the pulses of the generator 17 of the counter 18, the code is fixed, the value of which is proportional to the current duration of the fuel injection process tg. At the same time, the signal from the output of block 3 is fed to the single input of the trigger 16 and sets the latter into a single state (plot g in Fig. 2). The signal 1 from the output of the trigger 16 unlocks the valve 10 of the write pulses and sets the device 8 to sample and memorize the input signal from the output of the amplifier 2. Thus, at the time of injection, the output of the device 8 is fixed at a signal level UB proportional to the signal for injection start pressure UB (plot a in fig. 2). The fixed signal level from the output of the device 8 is fed to the input of block 9 of the comparison, to another input of which a varying signal comes from the output of amplifier 2. During the fuel injection process, with a decrease in drove the pressure at the output of the amplifier 2 at the moments of equality of the pressure signal to the value UB (moments tj, t4 on the plot a of Fig. 2). Comparison unit 9 generates pulses of a fixed duration (plot d in Fig. 2) received through the open valve 10 on the control input valves 19. By these signals, the valves 19 are unlocked and the counter code 18 is copied to memory register 20. Similarly, when the pressure signal decreases at the injection end at time ts, counter code 18 is copied to memory register 20, the value of which is proportional to STI injection ts. At the site of the fuel injection end, in the process of further slashing pressure, the signal at the output of amplifier 2 becomes equal to or less than the level Uy recorded at the output of device 13 for selecting and storing unit 11. At this point, the comparator 14 returns to reverse its value from 1 to O (plot b in Fig. 2). The differential signal level at the output of the comparator 14 triggers the trailing edge shaper 15 (plot e in Fig. 2) and generates a pulse of fixed duration, which arrives at the zero input of the trigger 16, and sets the latter to the initial zero state. The signal O from the output of the trigger 16 blocks the pulse valve of the front 10 and switches the sampling and storage device 8 into the sampling mode of the signal from the output of the amplifier 2. At the same time, by the difference in the signal at the output of the trigger 16, the control unit 22 generates a signal at the control input of the visual indication unit 21. By this signal, a memory register number code 20, proportional to the duration of the fuel injection, is recorded in the memory of the unit 21, decrypted and indicated. With the subsequent appearance of the signal at the output of block 3, the operation of the device is repeated. The refresh rate shown on the display of the unit 21 is set by the operator using the controls of the control device 22. Claim 1: A device for determining the duration of fuel injection into an internal combustion engine, comprising a pressure sensor with an amplifier associated with a block, an impulse generator closed through a counter with valves and an extra indoor unit with a control device at the input, characterized in that, in order to simplify the measurement process and improve accuracy , the amplifier output is connected in parallel with the signal inputs of the injection start signal generation unit, connected to the installation input of the counter, the sampling and storage device connected to the comparator unit, the spacing unit for measuring the interval, between the comparator unit and the valves the recording pulses valve is inserted between the valves and a block of extra-visual indication is connected to the memory register register, and the output of the form block; an; The injection start signal is connected to the / control input of the forming unit, the measurement interval, the output of which is connected in parallel with the control inputs of the sampling and memory device and the valve of the recording pulses and the control device. 2. The device according to claim 1, characterized in that the measuring interval shaping unit comprises a low-pass filter connected to one input of the comparator via a sample and memory device, and directly to the other, and a trigger, one input of which forms the control input of the forming unit the measurement intervals, and the other is connected through the back-edge driver to the comparator output, which is also connected to the control input of the sampling and memory device, and the trigger output forms the output of the interval shaping unit , SignalnSh input of which forms the input of a lowpass filter. Sources of information taken into account in the examination of the invention: 1. England patent No. 811910, cl. G 1 N, 1953. 2. US Patent N 3503255, cl. 73-117.2, 1969. 3.Technical diagnostics of internal combustion engines according to the parameters of working processes, M, GOSNITI, 1973, p. 137-149. L and A.LL Ui, ; y v / H h h at h