SU1684538A1 - Internal combustion engine ignition system - Google Patents

Abstract

The invention relates to electrical equipment of vehicles and can be used to create electronic ignition systems for internal combustion engines. The aim of the invention is to increase reliability by increasing the stability of the energy of sparking. The pulse generator is made controlled from the supply voltage, which ensures the stabilization of the time of current flow through the electrical switch when the supply voltage changes. 2 yl

Description

The invention relates to electrical equipment of vehicles and can be used to create electronic ignition systems for internal combustion engines / two /.

The aim of the invention is to increase the reliability of the system while at the same time increasing the stability of the energy of the neoplasm.

Fig. 1 is a diagram of the ignition system; figure 2 - diagrams of signals.

The ignition system contains a crankshaft position sensor 1, a pulse shaping unit 2, terminal 3, a control unit 4, a controlled pulse generator 5, a frequency divider 6, a multiplexer 7, a reversing counter 8, a decoder 9, an arithmetic unit 10, terminal 11, RS -trigger 12, electrical switch 13, ignition coil 14, power bus 15, spark gap 16. Sensor 1 is connected to the input of pulse shaping unit 2, the output of which is connected to the multiplexer control input through the input of the reversing counting input of the control unit 8, the first output of which is connected to the R input of the reversible counter 8 and the R input of the RS flip-flop 12. The second output of the control unit 4 is connected to the input of the PE - preset - reversing counter 8. Information outputs of the reversing the counter 8 is connected to the first information input of the arithmetic unit 10 and the input of the decoder 9, the output of which is connected via terminal 11 to the S-input of the RS flip-flop 12, the output of the latter is connected to the input of the electrical switch 13. The first output of the switch 13 is connected to the common bus power supply, and the second is connected to the common output of the primary and secondary windings of the ignition coil 14. The second output of the primary winding of the ignition coil 14 is connected to the second power supply bus 15, the second output of the secondary winding is connected through a spark gap 16 to a common power supply bus. The information input of the reversible counter 8 is connected to the information output of the arithmetic unit 10, to the second information input of which

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ABOUT

00 4 SL CO 00

Bus 17 (Z1) of the initial installation code is connected. The counting input of the reversible counter 8 is connected to the output of a multiplexer 7, the first input of which is connected to the output of frequency divider 6. The input of the frequency divider and the second input of multiplexer 7 is connected to the output of a controlled pulse generator 5, the input of which is connected to the second power bus 15.

The system works as follows.

Through a constant angle of rotation of a rotating motor shaft, a level 1 signal is applied to terminal 3, and an angle of 0 at the angle a, with (a- + az) a constant value determined by the design of the engine and distributor. The end of the angular sector ai (time instant ts in Fig. 2) corresponds to the moment of spark formation. At the beginning of the counting cycle, the falling edge of the pulse from the sensor (time ti) of the control unit 4 generates a pulse R of setting the reversible counter 8 to its initial state. Throughout the angle a (level 1), the reversible counter 8 is turned to the right through the input ± 1 of the counting direction (addition). At the same time, under the influence of the signal from the sensor, the counter pulses with a frequency fi are sent through the multiplexer 7 to the counting input C of the reversible counter 8. At the same time, the numerical value Z, which can be read from the counter output (solid line in FIG. 2), increases. In the arithmetic unit 10, the numerical value of Z is summed with the constant numerical value of Zi so that the numerical value of the reversible counter 8 all the time is applied the numerical value of Z - Zi. At the time point ta, the control unit 4 generates a pulse PE of the installation of the reversible counter 8 and the numerical value Z - Zi is entered into the counter, i.e. the numerical value that can be read from the counter output at the time of step 2 decreases by the ZL value. Due to the change in the signal level at the input ± 1, the counting direction of the counter changes at the same time, as well as due to the change in the signal level at the input multiplexer 7, the counting frequency fi is changed to f2. The numerical value Z read from the outputs of the reversible counter 8 decreases even when the value Z0 0 is reached. At the output of the decoder 9 a logical level 1 appears (time instant ts). Under the influence of the signal from the output of the decoder 9, the output of the RS-flip-flop 12 appears at a logic level 1, which is fed to the input of the electrical switch 13 and the current flow circuit in the primary winding of the ignition coil 14 is closed. In the primary winding of the ignition coil 14, a ramp current I. flows at the moment ts on the pulse front from sensor 1, control unit 4 generates a reset pulse for RS flip-flop 12 and for counter 8. At the numerical outputs of the counter a numeric value is set Z0 0, and at the output of RS-flip-flop 12, a logic level O appears, which, acting on the electrical switch 13, breaks the current flow circuit in the primary winding of the ignition coil 14. As a result, an electrical discharge occurs in the spark gap 16. A reset pulse for the RS flip-flop 12 for the reversible counter 8 prepares the circuit for the next counting cycle.

When performed for the frequency counting ratio fi / fz ac / a. 1 time At closure

electrical switch 13 will be determined by the formula At Zi / f2 and at a constant value Zi depends only on the counting frequency. As is known, the flow of current in the primary winding of the ignition coil

from the moment it is turned on, is described by the equation

1 (1) 1o (1-e-1 / P

where i (t) is the current in the primary winding of the ignition coil at the current time t; o. U / R is the maximum possible current value in the primary winding of the coil with an infinite rise time; R is the resistance in the current flow circuit; U is the voltage of the power source connected to the primary winding of the ignition coil; С L / R is the time constant of the current flow circuit; L is the inductance of the primary winding of the ignition coil,

At the initial linear portion of the current rise, the expression

45

i (t) lo

t U-t

In order to maintain the current constant p of the opening of the electric switch, which is necessary for stabilization, the spark energy, the value At of the time of rise of the current in the primary winding of the coil must be determined from the ratio

55

At

and

If Zi is the number of clock pulses received at a frequency f at the counting input of the counter during At, then At Zi / f.

Equality follows from the last two equations.

I U 21.

IP - -J-TL Thus, in order to obtain a constant energy of a neoplasm with changes in the supply voltage, the frequency of the clock pulses must be directly proportional to the supply voltage.

Fig. 2 shows the variant of the operation of the ignition system with a proportional increase in the voltage of the power source connected to the ignition coil 14 and the frequency of the clock pulses produced by the controlled generator 5. The increase in the amplitude of the signals at terminals 3 and 11 as well as the inputs R and A PE counter may not be available if the circuit is powered by a stabilized secondary source.

Claims (1)

An ignition system for an internal combustion engine comprising an engine crankshaft position sensor, wherein the sensor output is connected to an input of a pulse shaping unit whose output is connected to a control input of a multiplexer, an input of the counting direction of a reversible counter, an input of a control unit, the first input of which connected to the R input of the reversible counter and the R input 0 five 0 50 RS-flip-flop, the second output of the control unit is connected to the presetting input of the reversible counter, the information outputs of which are connected to the first information input of the arithmetic unit and the input of the decoder, the output of which is connected to the S input of the RS-flip-flop, the output of which is connected to the input of the electrical switch , the first output of which is connected to the common power rail, and the second output to the common output of the primary and secondary windings of the ignition coil, the second output of the primary winding of the ignition coil is connected to the second another power supply, the second output of the secondary winding is connected to the common power supply bus through the spark gap, the information input of the reversible counter is connected to the information output of the arithmetic unit, the second information input of which is connected to the initial setting code bus, the counting input of the reversible counter is connected to the multiplexer output, the first input of which is connected to the output of a frequency divider, the input of which and the second input of the multiplexer are connected to. an output of a pulse generator, characterized in that, in order to increase the reliability of the device, while simultaneously increasing the stability of the sparking energy, the pulse generator is controllable, the input of the generator being connected to the second power bus. 15 tx