SU1442688A1 - Contactless ignition system - Google Patents

Abstract

The invention relates to contactless ignition systems for reciprocating internal combustion engines and can be used in the automotive industry for models with improved toxicity and economy. The purpose of the invention — improving reliability — is achieved by reducing the number of semiconductor and resistive elements of an electrical circuit of an adaptation unit. The ignition system contains an angle marker sensor 1, in which the Hall-effect micro switch can be used, the accumulation time control unit 2, which contains the integrator 3 times, the time comparator 4 connected in series and the source 5 of the reference voltage. The ignition system also contains a synchronization device 6, an adaptation block 7 comprising an integrator 8 and a comparison block 9, a power stage 10, the primary winding 11 of the ignition coil 12, sources 14 and 19 of the reference voltage, resistors, capacitors, diodes shown in the drawing. The execution of the comparator unit and the integrator adaptation unit on current-difference amplifiers and the introduction of bias resistors improve the reliability of the ignition system. 2 Il. e (L

Description

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The invention relates to contactless ignition systems for reciprocating internal combustion engines and can be used in the automotive industry for models with improved toxicity and economy.

The purpose of the invention is to increase reliability by reducing the number of semiconductor and resistive elements of the electrical circuit of the adaptation unit.

FIG. 1 shows a circuit diagram of a contactless ignition system; in fig. 2 - voltage and current diagrams on the main nodes of the circuit.

The contactless ignition system contains a sensor of 1 angle mark, which can be used as a Hall effect microswitch, a accumulation time control unit 2, a integrator 3 times, a time comparator 4 connected in series and a voltage source 5 (t / oni), sparking timing synchronization device 6 with a time comparator 4 output signal, the first time integrator input 3 is connected to the output of sensor 1, the second time integrator input 3 is connected to the input of adaptation block 7, Yerzhash, his integrator 8 with the first and second inputs and the comparison unit 9 (comparator), the output of the accumulation time control unit 2, which is the output of the comparator 4, is connected to the input of the power stage 10 equipped with at least one commutator, its first element the output of the power stage 0 is connected via the primary winding 11 of the ignition coil 12 to the first power bus, its second output is connected to the second power bus through the measuring resistor 13, the first input of the adaptation unit 7, which is the first input of the reference block 9, is connected to The second output of the power stage 10, the second output of the adaptation unit 7, which is the second input of the comparison unit 9, is connected to the source 14 of the reference voltage connected to the power buses, the first input of the integrator 8 is connected via the charging resistor 15 , the second input of the integrator 8 through the discharge resistor 16 is connected to the output of the co.parator 4 of the accumulation time control unit 2, the resistors 17 and 18 are mixed between the inputs of the integrator 8 of the adaptation block 7 and the additional source 19 of the reference voltage Connected between the supply rails.

The ignition system works as follows.

The signal of the angle mark sensor 1 (Fig. 2 and), which carries information about the rotational speed of the engine crankshaft, controls the process of charging and discharging the capacitor of the intogtor 3 to the time of the accumulation time control unit 2. Signal sawtooth integrator 3 (/ 721) cf.

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The comparator 4 times with the level of the reference voltage (/ op, resulting in the output of the comparator 4 produces a square voltage signal (i / as), the duration of which corresponds to the energy accumulation time in the primary winding of the ignition coil. This signal controls time of the open state of the output transistor of the power stage 10, as a result of which the primary current 11 of the ignition coil 12 flows the primary current (/ 4 °), which stores energy in the ignition coil 12. In the absence of a rectangular signal at the output When the comparator 4 is closed, the output transistor is closed, and the energy stored in the primary winding 11 of the ignition coil 12 is transformed into the secondary winding of the ignition coil 12 and released as spark energy in the spark gap. The output transition of the output transistor from the open to the closed state is synchronized with the signal front sensor 1 of the angular marks by the block 6 synchronization of the moment of sparking, namely the low level of the output signal of the sensor 1 of the angular marks locks the transistor of the synchronization circuit, in As a result, the input from the comparator 4 receives a current from the power supply 8. With this current, the comparator switches from a state of logical 1 to a state of logical "O (t / 25). The rising primary current of the ignition coil 12 creates a voltage drop across the resistor 13 of the current primary value measurement circuit. The voltage signal of the current value of the primary current of the ignition coil 12 is compared in comparator 9 with the signal of the set value of the primary current / o (/ 4o) specified by the level of the source 14 of the reference voltage, and for convenience of comparing the signals the reference voltage level is equal to half of the signal of the specified value current supplied to the comparator 9, i.e. / 3. The set value of the primary current is selected based on the optimal, from the point of view of heat heating, the ignition coil 12 and the power stage 10. Comparing the signals of the current and set values, the primary current at the output of the comparator 9, a signal characterizing the current error ((745). This signal is rectangular the form, the duration of which is greater, the greater the magnitude of the mismatch of the currents, controls the charging process, the time of the driving capacitor of the integrator 8 of the adaptation block 7. The higher the level of the capacitor a, the greater the level of the signal acting on the integrator 3 of the accumulation time control unit 2, the higher the charge level of the integrator capacitor. oor 3, the longer the discharge signal of the sawtooth shape of its capacitor, the smaller the square signal at the comparator 4 output.

the transistor of the power stage 10 is opened for a shorter time and the current flow has time to increase to a smaller value. This causes the current value of the primary current to be closer in magnitude to the signal of the given value of the primary current, while the magnitude of the current mismatch decreases as compared to the previous value "as long as the signals of the current and given value of the primary current do not match amplitude ((/ 5o). in this case, the signal of the integrator 8, controlling the charge of the capacitor of the integrator 3, does not cause a change in the current value of the primary current of the ignition coil 12, and therefore the amount of stored energy in its primary winding 11. Discharge of the capacitor of the integrator 8 is carried out by the signal of the comparator 4 time and continues until the signal on the charge time of the driving capacitor is received, and the feature of the Norton current-difference amplifiers used in the invention is used to control its operation differences of currents at the amplifier inputs, for this, the resistors on the first and second inputs of the integrator 8, characterizing respectively the constant charging and discharging times of the driving capacitor, are chosen in the ratio II 1: 2.

The amplitude of the correction level signal varies depending on the magnitude of the current mismatch and reaches a certain value, and when the amplitude of the current value signal becomes equal to the amplitude of the signal of the specified current value. In this case, the level of the discharge voltage Up The time of the driving capacitor of the integrator 8 becomes equal to the level of the charging voltage, i.e.

The discharge voltage Up with a sufficient degree of accuracy is calculated by the formula

Ua ip / C- tp,

where ip is the discharge current and time of the driving capacitor of the integrator 8; C - capacitance time of the reference capacitor of the integrator 8;

discharge time setpoint capacitor integrator 8. Thus, the implementation of the comparison device and the integrating device of the adaptation unit on the current-difference amplifiers tp - time

L x with the connection of the first input of the integrator 8 with the output of the comparison unit 9, and the second input with the output of the comparator 4 of the accumulation time control 2, as well as the introduction of bias resistors connecting the inputs of the integrator 8 with the voltage source increase the reliability of the ignition system by reducing the number of semiconductor and resistive elements of the unit

adaptation.

Claims (1)

Invention Formula 0 A contactless ignition system containing an angle marker sensor, an accumulation time control unit containing a serially connected time integrator and a comparator, the first time integrator input of the accumulation time regulating unit is connected to the output of an angular level sensor, the second time integrator input is connected to the output of the adaptation unit containing an integrator with the first and second inputs and a comparison unit; the output of the accumulation time control unit, which is the comparator output, is connected to the input the power stage supplied with at least one switching element, the first output of the power stage is connected via the primary winding of the ignition coil to the first power bus, its second output is connected to the second power bus through the measuring resistor, the first input of the adaptation unit, which is the first input of the unit comparison, is connected to the second output of the power stage, the second input of the adaptation unit, which is the second input of the comparison unit, is connected to the source of the reference voltage, which differs from the fact that, in order to increase reliability, the first and second bias resistors and an additional voltage source are introduced, in the adaptation unit the first integrator input is connected via a charging resistor to the output of the comparator unit, the second integrator input is connected to the output of the accumulation time control comparator through the discharge resistor, and The first and second bias resistors are connected between an additional voltage source connected between the power rails and the inputs of the integrator of the adaptation unit. 21 Vonl ag.2