DE2541885A1 - IGNITION ARRANGEMENT - Google Patents

Description

The invention relates to a contactless ignition arrangement, in particular with a duty cycle control element that is used to switch the ignition timing of internal combustion engines suitable is.

The ignition point (ignition timing) of an ignition arrangement for internal combustion engines is preferably according to the technical data or the specification of the relevant Internal combustion engine or designed to achieve the cleanest possible exhaust gas.

To achieve this, an arrangement that has already been developed has a switching device with two measuring sensors (to be used for advance and retardation), which are each assigned to different ignition times, so that a desired measuring transducer is used depending on the state of the environment of the machine.

81 (Al111-05) KoIs

6098U / 0926

For example, if the water temperature of the machine is low is detected by a water temperature sensor, a start signal is generated to thereby create a start sensor to energize while a lead sensor is operated for continuous operation.

However, this method has the disadvantage that the number of parts, e.g. B. a transducer coil, a resistor and the like, is large, resulting in a higher cost.

It is therefore the object of the invention to provide a contactless ignition arrangement for internal combustion engines that is simple is built up and the ZUndZeitpunkt-delay angle can control according to the operating status of the machine; the characteristic of the delay angle should be able to be changed automatically according to the machine speed.

According to the invention, a first transistor is through a AC signal controlled that is synchronous with the machine speed is generated, and a power transistor for Control of the primary current of the ignition coil is controlled by the output of the first transistor. To the Ignition timing by detecting the operating state of the machine, e.g. B. the temperature of the machine's cooling water, control is an additional ignition timing control device via the ordinary or main ignition arrangement also provided. This additional ignition timing control device generates a signal in synchronism with the output signal of the first transistor accordingly the operating status of the machine. This signal is combined with one on the output of the first

6098H / 0926

Transistor-based signal fed into an OR gate, the output signal of which is used to control the power transistor serves. In this way, the ignition timing is through under normal operating conditions that based on the output of the first transistor Signal controlled, while under special operating conditions the ignition timing is controlled by the duration corresponding to the output signal of the additional ignition timing control device delayed from the time of generation of the output signal of the first transistor which enables more precise and sophisticated control. So around the ignition timing accordingly Delaying the engine operating condition is one beyond a main ignition timing controller additional ignition timing control device is provided. The additional ignition timing control device a delay angle signal in synchronism with the signal generated by the main ignition timing controller will. A transistor for controlling the primary current of the ignition coil receives the through via an OR gate the main ignition timing control device and the additional ignition timing control device generated Signals so that the primary current of the ignition coil is controlled to adjust the ignition timing.

The invention is described below with reference to the drawing explained in more detail. Show it:

1 shows a circuit diagram of a contactless ignition arrangement according to a first embodiment of the invention;

6098 U / 0926

Pig. 2 shows the course of the output signal of the measurement receiver -S coil j

Fig. 3 is a timing chart for explaining the operation of the first embodiment (Fig. l) i

4 shows a comparison diagram for the crank angles versus various engine speeds;

Fig. 5 is a circuit diagram of a further embodiment of the invention, and

Fig. 6 is a timing diagram for explaining the operation of the further embodiment (Fig. 5).

In Fig. 1, a transducer coil 1 is in one Distributor provided, one end of which is connected to a diode 2, the cathode of which is grounded a current source (mains) - VB is connected via a resistor 3. The other end of the transducer coil l is connected to the base of a transistor 8 via a filter element made up of a resistor 4 and a Capacitor 5 and a compensating element from one Capacitor 6 and a resistor 7 connected. Furthermore, a collector resistor 9, a signal shaper 10 and an amplifying transistor 11 are provided, the emitter of which is grounded and the base of which is via a resistor 12 is connected to the signal shaper 10. The collector of the amplification transistor 11 is via a resistor 13 connected to the network VB. A transistor 14 of the second stage is grounded with its emitter and

6098U / 0926

with its base with the base of the transistor 11 connected to the first stage. A collector resistor 15 is also provided. A switching transistor 16 including a Darlington member has its base connected to the collector of the amplifying transistor 14 and with its collector with the primary winding 17a of the ignition coil 17 is connected. Furthermore are a Current limiter resistor l8 and a spark plug 19 are provided.

The following is the additional ignition timing controller 20 explained in more detail. A diode 21 has its cathode connected to the collector of transistor 8 and with its anode on the one hand via the resistor 22 to the supply line and on the other hand via a Capacitor 23 connected to the base of a transistor 24. Furthermore, a resistor 25 and a changeover switch 26 are provided between the supply line and the transistor 24 and is excited in response to the actuation of the water temperature sensor. The switch 26 is connected to the collector via a resistor 27 of the transistor 'connected and can be a bimetal member. Furthermore, there is a resistor 28 between the base of the transistor 11 and the collector of the transistor 24.

With this circuit structure it should be assumed that the engine is started and the distributor is operated. An output signal with that shown in FIG The course shown is obtained in the transducer coil. Since the forward or forward voltage drop Vf across diode 2 is greater than the base-emitter-front

6098U / 0926

If the voltage drop V _n ^ of the transistor 8 is, the circuit is constructed so that the transistor 8 conducts when the output signal of the transducer coil is zero.

Assuming the output voltage of the transducer coil 1 becomes negative with respect to the base of transistor 8, a pulse signal occurs with the Course (A) of Fig. 3 at the collector of the transistor. While the pulse signal (A) of Fig. 3 in positive Increases in the direction of zero, a signal of increasing voltage, as shown with (B) in Fig. 3, on Point (B) in Fig. 1 obtained, which is charged with the time constants of the resistor 22 and the capacitor 23 if it is held at zero by the collector voltage of transistor 8. In this condition it flows the charging current for the capacitor 23 in the form of the Base current for transistor 24, so that transistor 24 is turned on is held. The electric charges stored in the capacitor 23 are re-energized of transistor 8 released. After that point (B) is again with the time constant of the resistance 25 and the capacitor 23 charged. (The one in the condenser 23 stored charges are in particular via the resistor 25, the diode 21 and the transistor 8 enabled.) During this time, the transistor 24 is kept in the off state. The peak voltage values at points (B) and (C) agree with coincide with each other, as shown in Fig. 3 with (B) and (C), since the loading and unloading operation of the Capacitor 23 is used to generate the voltages (B) and (C). It is to be assumed that

6098U / 0926

the resistors 22 and 25 have large values and the current changes at a fixed rate (cycle) over time. When the speed is twice as high is reduced, the peak value is approximately halved (the period also halved), since the Time constant remains unchanged. The duty cycle at point (C) is also reduced to half, and therefore, it is possible to adjust the ignition timing by means of a certain delay angle with respect to the engine speed to control.

Assume that switch 26 is on when a high water temperature is sensed will. The output signal (E) of the signal shaper 10 is with the output signal (D) of the additional ignition timing control device are combined, whereby the transistors 11 and 14 perform a switching operation and feed a signal to the power transistor 16. as As a result, a signal designated by (F) in FIG. 3 is generated at point (F) on the primary side, which signal is delayed by θ is.

At the start-up time of the machine, when the temperature of the cooling water is low, on the other hand, the switch 26 is turned off and therefore there is no output from the additional ignition timing control device generated.

For the above-explained circuit experimental results show that the duty cycle of the signal (A) of Figure 3 is. About 20%, so that the charging voltage curve (B) of FIG. J> is sufficiently extended at a low speed level (by the

609814/0926

Distributor intended) not to be saturated while the charging voltage curve (C) one third of that of the Signal (B) is. In this way, an accuracy of approximately 2 ° crank angle is compared to the mechanical lead angle characteristic (a) between 600 and 5000 rpm machine speed reached, such as this is shown in FIG. Furthermore, dxe according to the invention Arrangement in contrast to a conventional two i-point arrangement, which is a relatively Requires large numbers of parts to be realized with only a few parts, resulting in low manufacturing costs leads.

The signal shaper converts the signal form (A) in Fig. 3 into the signal form (E) in FIG. 3, and can have two current or inverters connected in series. The signal shaper 10 does not always have to be used; instead, the resistor 12 can be connected directly the collector of the transistor 8 can be connected, an arrangement then being achieved with less effort will.

Another embodiment of the invention is explained below with reference to FIG. In this figure, corresponding parts are provided with the same reference numerals as in FIG. 1. A resistor R ₁₀ in the additional ignition timing control device 20 has one connection to the supply line and the other connection to a capacitor CU and the collector of a transistor Qg connected. The emitter and the base of a transistor Q ₇ ■ are connected to the supply line via resistors R and R, ^, while the collector is connected to the capacitor

6098H / 0926

CU is connected. The base of the transistor Qn is connected to the collector of the transistor Q ₇ , while the collector of the transistor Qn via a resistor R -., _ To the base of the transistor Qg via a resistor Rg and the changeover switch 26 to the supply line and a resistor R _{17 is} connected to the base of transistor 11. A capacitor Cp and a resistor R ... are also provided.

In this circuit construction, a rotation signal induced in the transducer coil 1 is formed by the transistor 8, as indicated by (A) in FIG. 6, and reversed in phase by the transistor Q. The base of the transistor Qg is activated at the off time of the transistor Q ₂ , whereby a signal with the curve designated in FIG. 6 with (B) is generated at point (B). The transistors Qg and Qg then act as a monoflop (monostable multivibrator). Subsequently, the base of the transistor Qg is driven at the on-time of the collector of the transistor Qg, whereby a signal with the waveform denoted by (D) in FIG. 6 is obtained. In this way, a precise control of the duty cycle is achieved, the charging current for the capacitor Q- flows as a constant current in the resistor R ₁₂ ', transistor Q ₇ , capacitor C-, and transistor Qg.

When the switch 26 is on, the fall Points (E) and (D) in Fig. 5 together, so that point (F) retards the ignition by a certain angle is, as shown in Figure 6 with (F).

609814/0926

On the other hand, as long as the changeover switch 2.6 is switched off, there is no angular delay, since the on-off operation is only carried out with the signal (E) in FIG.

In the embodiment shown in FIG the signal conditioner can consist of an ordinary switching element, i.e. a converter itself.

This exemplary embodiment, like the exemplary embodiment, is also made possible 1 shows an ignition timing control with a relatively simple circuit arrangement.

609814/0926

Claims (4)

Claims ( I. i ignition arrangement for internal combustion engines, with an ignition timing signal generator for generating an alternating current signal synchronous to the engine speed, with a first switch that can be excited by an output signal from the ignition timing signal generator, with an ignition coil including a primary winding and a secondary winding, with a Le is processing transistor for controlling the primary current in the primary winding of the ignition coil, whereby a high voltage can be generated in the secondary winding of the ignition coil, and with a second switch for controlling the base current of the power transistor, v / above the second switch through a The output signal of the first switch can be excited, characterized by an additional ignition timing control device (20), which is responsive to the operating conditions of the internal combustion engine and the first switch to a delay angle signal to generate an OR gate, a device for feeding in an output signal of the first switch in the OR gate, and a device for feeding in an output signal of the additional Ignition timing control device (20) in the OR gate, wherein the second switch can be controlled by the output signal of the OR gate. 609814/0926 2. Ignition arrangement according to claim 1, characterized in that that the additional ignition timing control device (20) one according to the operating conditions the internal combustion engine has excited third switch and depending on the operation of the third Switch generates an output signal. 3. Ignition arrangement according to claim 2, characterized in that the additional ignition timing control device (20) a diode (21) which has an output signal receives from the first switch, comprises a capacitor (2J) and a second transistor (24), wherein the charging current for the capacitor (23) through the base of the second transistor (24) and the discharge current from Capacitor (23) flows through the diode (21). 4. ignition arrangement according to claim I ^ characterized in that that the additional ignition timing control device (20) has a monoflop (Qg, Qg) (FIG. 5). 6098U / 0926 , ts . Blank page