SU979685A1 - Fuel injection advance angle indicator - Google Patents

Description

The invention relates to the measuring technique and is intended to measure the angles of advance of the fuel supply to the cylinder of an internal combustion engine.

Known fuel advance angle indicators I containing dates. injector needle lift, driver, trigger, top dead center sensor (TDC) 1 zero-level detector, valve, frequency meter, synchronization unit and external control and potential sources, the elevator lift sensor is connected through the driver to one trigger input, the TDC sensor is connected through a zero level detector with a different trigger input, valve inlets are connected to the formers, trigger and frequency meter outputs, and the valve output is connected to the counter input of the frequency meter.

The signal from the nozzle lift sensor of such an indicator goes through a driver to one trigger input, to the second input of which an TDC sensor signal is received through the zero level detector. A trigger signal is generated at the trigger output that is equal to the fuel advance. This signal comes

to the input of the converter and further to the recorder P 3.

A disadvantage of the known indicator is the low measurement accuracy due to the presence of an analog converter and a recorder.

The purpose of the invention is to improve the accuracy of measuring the angle of advance injection as fuel.

ten

The goal is achieved by the fact that, in the fuel injection advance angle indicator, the synchronization unit is designed as a 0-flip-flop and a one-shot, connected in series, the one-shot output is connected to the control input of the frequency meter. The D-flip-flop input is connected to the driver's output, D-input - to the source of the potential of a logical unit, and

20 S-out - to the source of external control.

Fig.1.1 shows a diagram of the fuel injection advance indicator; 2 is a diagram, as shown in FIG.

The fuel injection advance angle indicator includes a nozzle needle lift sensor 1 connected to a driver 2; TDC sensor 3 connected via zero-level detector 4

with one input of the trigger 5, the second, the input of which is associated with the output of the driver 2; valve b, the inputs of which are connected to the output of the trigger 5, the driver 2 and the output of the reference frequency of the frequency meter, the counting input of which is connected to the output of the valve 6, the synchronization unit 8, consisting of D-T.frigger 9 and the single-oscillator 10 in series, the output the one-shot 10 is connected to the control input of the frequency meter 8. The C input of the D flip-flop is connected to the output of the imaging unit 2, the D input to the potential of a logic unit, and the S-input to the external control.

The operation of the indicator is as follows.

The signal from the nozzle needle lift sensor 1 (output in Fig. 2) is fed to the inlet of the former 2. A positive polarity pulse (output 2) is formed at its output (the leading edge of which corresponds to the start of fuel injection). - Signal of the 3 TDC sensor (output 3) to the post; it goes to the detector input 4 of zero level, the output of which forms a rectangular pulse (output 4) of positive polarity, the leading edge of which corresponds to the moment of transition through the zero signal of the TDC sensor 3. The first input of the trigger 5 receives a rectangular pulse from the output of the imaging unit 2, which does not change the state of the trigger 5. The second input of the trigger 5 receives a pulse from the output of the detector 4, which transfers the trigger 5 to another stable state, and at the output the voltage decreases from a logic unit level to a logic zero level.

A rectangular impulse from the output of the former 2- comes to the first input of the valve b, a pulse from the output of trigger 5 arrives at the second, and a reference frequency from the output of the frequency meter 7 to the third impulse voltage. The reference frequency pulses pass to the output of the valve b only those time intervals when signals of logical units are present on the first and second inputs, i.e. from the start of injection to TDC (exit 6). Thus, at the output of the valve b, an electric pulse packet appears, the number of which is equal to

hh.

(one)

where ton is the time interval corresponding to the advance of fuel injection; T - the period of the pulse

reference frequency Frequency meter 7 operates in frequency measurement mode. In this mode

The inner unit automatically generates a precision time interval t during which the pulses received at its input are counted. The number of packets arriving at the input of the frequency meter 7 is determined by the ratio of the measurement time interval tn and the pulse following period Ti, i.e.

K. (2)

t 60 (3)

.1 is the coefficient of engine tact ((two-stroke, i-four-stroke), n is the frequency of crankshaft rotation.

Rare number of pulses, arriving at a frequency meter,

m

ter,

N is the total number of pulses, SfeOi

tn

(five)

Considering that the injection advance angle can be expressed

(b)

 one

op

(7)

 N,

op av w p

where i, T, n, t are constant values known in advance.

Therefore, a number proportional to the average angle of fuel injection, expressed in degrees of rotation of the crankshaft, is indicated on the indicator board of the frequency meter.

The synchronization unit 8 makes it possible to synchronize the start of the frequency meter in the measurement mode simultaneously with the commencement of the fuel supply to the diesel cylinder.

When an S-input of a D-flip-flop 9 of an external control pulse is applied, its potential is set to a logic zero at its output. This potential is preserved until the front of the pulse arrives from the driver 2 at the C input, after which the output of the D flip-flop 9 again sets the potential of the logical one. During the transition from a logical zero to a unit of potentials at the output of the trigger 9 at the output of the one-shot 2, a direct coal electric impulse is formed, the front of which coincides with the start of fuel supply (output 7).

Claims (1)

Thus, the odds of the interval t and In the frequency meter begins with the beginning of the fuel supply, i.e. synchronized. Without synchronization, due to the arbitrary orientation of the measuring time interval t, the number of packets of the impulse placed in the time interval t can differ by ± 1 packet, i.e. The measurement error without synchronization is "7s (8J or Taking into account equations (1) and (7) 1000L ... f If there are ciks, the loss of information is one pulse, i.e. the measurement error F" "-re ° For example, for four-contact diesel, at rpm, at tn 1 s and T 1.39-10 s (. 720 kHz), the measurement error is without the synchronization unit ± 40%, with the synchronization unit d 0.0047% (the errors are determined only by the loss of information ) The proposed indicator allows you to measure ii for a period of 1 sec in the protocol, the fuel injection advance angle averaged over several Formula of Invention A fuel advance fuel angle indicator comprising a nozzle needle lift sensor, a driver, a trigger, a dead center sensor, a zero level detector, a valve, a frequency meter, a synchronization unit, and external potential control sources, the needle lifting sensor being connected through the driver one trigger input, the top dead center sensor is connected via a zero level detector to another trigger input, valve inputs are connected to the output of the driver, the trigger and the frequency meter, and the valve output is connected to a counting input of a frequency meter, which is characterized by the fact that, in order to improve the accuracy of measuring the fuel injection advance angle, the synchronization unit is designed as a D-trigger and a one-shot connected in series, the one-shot output of the frequency meter G, The C input of the D flip-flop is connected to the output of the driver, the D input to the source of the potential of the logical unit, and the S input to the source of external control. Sources of information taken into account in the examination 1. French patent (f 2168665, class G 01 M 15/00, published 1973. External delight