Ignition system. Ignition system Show the principle of operation of the switch 131.3734

CAR CLUB

picky selection

VOLGA IGNITES

Hello, editorial? Advise something: for half a year already I change the third switchboard on "Volga"!

Mikhail KOLODOCCHKIN

When such calls began to be heard almost every day, the need for a "disassembly" became obvious. Indeed, why on earth did the ignition system of such familiar "402" engines suddenly become capricious on brand new "Volzhankas"?

Before grabbing an oscilloscope and a soldering iron, let's make a short but absolutely necessary

HISTORICAL FLASHBACK

Volga has always been distinguished by its originality. Having mastered contactless ignition back in the mid-eighties, at the same time she preferred a rotating magnet and a fixed stator winding to the Hall sensor. Such a decision required a switch that was completely different from the "eight". As a result, the scheme shown in Fig. 1 materialized under the "Volga" hoods.

The system responded to the principle of "nowhere easier". When the magnet rotates in the winding, a signal is generated that looks like a sinusoid - remember the school physics lessons. When the signal level is low, the switch connects the primary winding of the ignition coil to the on-board network, and when the signal is high, it turns it off. The magnitude of the current in the coil does not bother him at all - he stubbornly works on the principle of a switch: "opened - closed." And since the resistance of the primary winding of the B116 coil is only 0.43 Ohm, when it is directly connected to the on-board network, the current strength will reach 30 A - neither the coil nor the switch in this mode will last even a minute. To avoid trouble, an additional resistor with a nominal value of approximately 1.2 ohms is connected between the switch and the coil.

With the advent of the VAZ 2101, it became clear that a modern motor does not need such concessions - the resistor was refused a Togliatti residence permit. But it turned out to be more difficult to drive him out of Nizhny Novgorod ... Moreover, on the Volga there is not a simple resistor, but a two-section one! The first section is short-circuited at start-up - this is understandable, the “402nd” engine needs help. The second section is always on - frankly, not the best engineering solution.

The expulsion of the resistor from the non-contact ignition of the Volga dragged on for a dozen years. Finally, instead of a switch of type 13.3734, under the hood of the GAZ 3102 9 / "> GAZ 31029, almost the same-looking 131.3734 appeared, and the yellowish box with three terminals disappeared. It is not surprising that even electricians shrugged their shoulders at first, and rumors spread around the new product, one is more mysterious than the other. I have heard that the resistor was "hidden" inside the switch, that it was "withdrawn" according to a rationalization proposal to save money, and also that the malicious parts were simply not delivered to the conveyor ... It is not surprising that many unfortunate craftsmen began to correct " error" of the factory on its own, returning the resistor "in place".

Meanwhile, the new switch is an order of magnitude smarter than the old one. It automatically maintains the amount of current in the primary winding. To do this, a small but very important indicator resistance is installed in the transistor circuit, the voltage drop across which is monitored by a special microcircuit. If the current is small, the microcircuit “opens” the transistor, if it is large, it “closes” it. The same microcircuit saves electricity by connecting the coil to the on-board network back to back in time so that by the time of sparking it has time to accumulate the necessary energy. Finally, with the engine stopped, the new switch will turn off the coil altogether. As a result, despite the fact that instead of the variator resistor, the transistor itself is now blown away, the power dissipated on semiconductors has decreased.

An interesting fact: when you try to connect the mentioned resistor 1402.3729 in series with the coil, the power dissipated on the switch will not decrease, but increase! The reason is simple - the resistor increases the "time constant" of the system, and therefore, to achieve the desired breaking current, the switch will have to work longer (Fig. 2). Why do the car a disservice?

OPTIONS ARE POSSIBLE

So, why did the owners of the new GAZ 3110, who chose the good old “402nd” motor instead of the unpredictable “406th”, find not peace, but a headache. Is it really possible to get lost in three pines - a switch, a coil, a resistor?

Reference literature suggested that three types of switches can be used in the Volga ignition system: 131.3734, 90.3734 and 94.3734. The market made a correction - our collection was replenished with a product with a long name 468 332 008 ANALOGUE 131.3734. In addition, helpful sellers, as if by chance, offered outdated 13.3734, 13.3734-01, as well as another strange product - 468 332 007 ANALOGUE 13.3734. There were fewer ignition coils - modern 31.3705 was added to the old B116. Resistor 1402.3729 has not changed much.

It remains to solve a simple problem - from seven switches, two coils and one resistor, make up a team capable of controlling the ignition of the Volga and not experiencing mutual allergies.

First, let's deal with the coils. The electrical parameters of B116 and 31.3705 are practically the same, so any of them can ride the Volga. At the same time, the oil-filled "old woman" B116 has a higher survivability in case of overheating and other troubles, and therefore it is not worth sending her into retirement.

Switches will be divided into two groups - "old" and "new". "Old" (photo 1-3) do not know how to regulate the rise time of the current in the coil, "new" (photo 4-7) should be able to do everything.

Of the "old men", the most "solid" Iskra was Starooskolsky (photo 1) - a well-thought-out and tested design. The Ulyanovsk product (photo 2) looks almost the same, but worse. As for the other Ulyanovsk (photo 3), this is a complete failure. Those who made the switch housing from plastic doomed the power transistor (by the way, it is unmarked) to martyrdom in a slow fire: the heat sink area was reduced by a factor of three...

Let's move on to the "contemporaries". Stary Oskol traditions are inherited - there are no complaints about the switch 131.3734 (photo 4). Heredity can also be traced in Ulyanovsk (photo 5), but there is nothing to rejoice here. A parody of indicator resistance in the form of a printed conductor on the board was added to the disgusting heat sink. The Kaluga switchboard (photo 6) was made in good faith. Indicator resistance - purchased, with a stable characteristic. The ancient "Cheboksary" (photo 7) frankly did not like. Indicator resistance - in the form of a sloppy spiral of thin copper wire. Maintainability is poor - the screws are soldered to the board. And vertically mounted elements can easily fall off when shaking.

Thus, out of four "contemporaries" on the "Volga" two can ride - "Starooskolets" (photo 4) and "Kaluzhanin" (photo 6). The resistor 1402.3729 is contraindicated for them, and the coil can be any - both B116 and 31.3705. Unfortunately, under the hoods of the current "Volzhanki" outright hack-work periodically leaks out, ruthlessly killing the memories of the once trouble-free car.

Rice. 1. The classic scheme of contactless ignition of the "Volga": 1 - sensor-distributor; 2 - switch; 3 - additional resistor; 4 - ignition coil.

Rice. 2. Graph of the current rise in the coil with and without an additional resistor. The shaded area is the overheating of the switch.

Photo 1. Switch 13.3734–01 (Stary Oskol). The ancestor of non-contact ignition systems for the Volga. A kind of standard - the layout of the components is carefully thought out, the heat sink from the power transistor is good. Applicable only with additional resistor. Break current - 6.5 A.

Photo 2. Switch 13.3734 (Ulyanovsk). "Double" of the Stary Oskol "grandfather". The location of the components in terms of vibration and shock resistance is somewhat worse, but in general it is acceptable. The choice of the power transistor is unfortunate. Applicable only with additional resistor. Break current - 6.5 A.

Photo 3. Switch 468 332 007 ANALOGUE 13.3734 (Ulyanovsk). Illustration for the proverb "The best is the enemy of the good." For some reason, there was not enough space for the elements on one side of the board - I had to use the "wrong side". The thermal regime of the transistor is catastrophic. Applicable only with additional resistor. Break current - 6.5 A.

Photo 4. Switch 131.3734 (Stary Oskol). A solid product with a well-thought-out arrangement of elements and good heat dissipation from the transistor. The indicator resistor is a nichrome spiral of two or three turns. It is used without additional resistor. Break current - 7.3 A.

Photo 5. Switch 468 332 008 ANALOGUE 131.3734 (Ulyanovsk). Very heavy thermal regime of the transistor. The indicator resistor in the form of a printed conductor on the board does not provide accurate adjustment of the breaking current. The elements are very poorly located, the wiring is illiterate. It is used without additional resistor. Break current - 6.6 A.

Photo 6. Switch 90.3734 (Kaluga). Best in class. Indicator resistor - purchased, with a stable characteristic. Excellent heat dissipation from a foreign-made power transistor. High vibration and shock resistance design. It is used without additional resistor. The only puncture is too high a break current: 9.8 A, the coil may not withstand ...

Photo 7. Switch 94.3734 (Cheboksary). Degraded copy of Starooskolsky 131.3734. Indicator resistor - a spiral of copper wire, the resistance of which strongly depends on temperature. Low maintainability. Poor vibration and shock resistance. It is used without additional resistor. Break current - 6.8 A.

Ignition coils - "old" B116 and "new" 31.3705.

In the electronic ignition system, which is one of the most important components of a modern car, a high voltage current is created and distributed thanks to electronic devices. The electronic system has many distinct advantages and also makes it easier to start the engine in winter.

Ignition systems: from simple to better!

The ignition system is an essential attribute of any gasoline or gas engine. With all the variety of technical nuances in this matter, all ignition systems with dynamic distribution of the supplied voltage can be divided into contact and non-contact. The following article is devoted to their main features, as well as the reasons for the emergence of systems with static voltage distribution (electronic ignition).

Comparison of switches 13.3734 and 131.3734

Judging by the materials of the conference, many UAZ owners changed the standard switch 13.3734 to "Volgovsky" 131.3734 or similar. At the same time, a lot of stories are told about how much the dynamics, economy, idle speed stability, etc. have improved.

I also "decided to try it, took the bottle, opened it" (c). The miracle, as expected, did not happen, since the engine was already working quite well, so it was decided to dig deeper and replace the sensations and impressions with more accurate data.

So, starting positions. There are two switches: native - 13.3734 and 94.3734, produced by "ELARA". There are diagrams of both, one from the manual, the other from an article on UAZBUK. Datasheet for the L497 chip. Pointer ammeter and oscilloscope S1-94.

A decent amount of "information for reflection" (s) can be obtained by looking at the voltage waveform at the output of the switch. Therefore, the main efforts were directed to obtaining it for competing devices. I ask for pictures that show the output voltage of both switches. The time parameters correspond to approximately 1000 rpm. Let's start with native:

A spark is like a spark. Everything is in order - high voltage surge, gap breakdown, arc burning, its extinction after the energy in the coil is exhausted, after a while the switch turns on again and remains in this state until the next spark. The output transistor switch has two states - on and off. Moreover, the duration of the off state decreases with an increase in the number of engine revolutions (sparking frequency).
Those. almost all the time current flows through the coil, and if it is not further limited, it and the transistor key will have a bad time (based on the parameters of the coil, the current can reach 20 amperes with a tail). Well, yes, the authors of the ignition system took care of this, and provided us with a limiting resistor - a variator that limits the direct current through the coil at a level of about 7.5A. (It is a variator, apparently, because it has a tap for closing its part at start-up.)

Be curious about the dependence of the current through the coil on the engine speed. It turns out that the heaviest mode in terms of heat is idling. So, if your machine works for a long time at low speeds or at idle - the bobbin does not stay cold! Moreover, the variator is located below the reel, additionally heats it.
With the engine turned off, but the ignition on, the switch periodically spontaneously generates a spark, somewhat reducing the current consumption and making it easier to start the engine at very low speeds (in cold weather or from the handle). Let's count for dignity.

And here is the same voltage generated by the "Volgovsky" switch. It's smarter.
The cycle (phase 1) begins with the opening of the key. The current in the coil increases exponentially, tending to the above 20A. But does NOT reach them! Since the output transistor is transferred by the L497 control chip to the active mode (phase 2) and limits the current. Takes on the function of the variator. Variator NOT NEEDED! The transistor limits the current to 6A, providing a constant energy stored in the bobbin, and therefore given to the spark. The variator with this switch is HARMFUL! It does not allow the current, especially at low voltage in the on-board network during start-up, to reach the limit value and violates the stabilization of the pulsed current through the coil.

A little trouble - during the operation of the output transistor in the current stabilization mode, about 50 W of power is dissipated on it! Not for long, of course, but still ...
Finally, the transistor closes on a signal from the distributor sensor - a high voltage pulse and a spark are formed. The voltage pulse is higher than that of the 13th switch, but shorter. Most likely, this is due to the fact that they have capacitors of different capacities in parallel with the transistor. The 13th has 1uF, and the 131st has 0.1uF. But the areas under the half-wave are close, i.e. the energy is about the same. And the duration of the spark is almost the same as the 13th. At the end of the spark, the key does not think to open (phase 4). The commutator waits for phase 1 calculated by the control chip from the previous half revolution of the motor. Those. most of the time, the output transistor of the switch is closed. At least at low speeds.
Look at the dependence of the average current through the bobbin on the speed. Here everything is "exactly the opposite" in comparison with the 13th switch. XX is the easiest mode for the reel. Moreover, if the engine stalls, after about 1 second, the output transistor will be closed by the control chip. The consumption of the ignition system will be equal to the consumption of the control circuit - 50 milliamps ... But no more sparking without a signal from the distributor. If the engine rotates slowly, and the amplitude of the signal from the sensor is insufficient to trigger the shaper, you will be left without a spark!

A little about the L497 chip, invented by the glorious SGS Thomson. This is a specialized analog-pulse computing device, where the time parameters are set by capacitors. These are not the most accurate and stable radio elements.
The microcircuit has the following functions, partially mentioned earlier:

• Controlling the opening angle of the output transistor.
• Output current limitation.
• Output high voltage limitation.
• Turning off the output transistor in the absence of a signal from the sensor.
• Formation of a signal for a tachometer.
• Protecting itself from electrical overloads.

1. The dialectic is there. Each device has its own advantages and disadvantages. And both are not masterpieces of ignition engineering.
2. The energy of the spark generated by both ignition systems is approximately the same. So with good spark plugs, wires and a distributor, you should not expect a noticeable improvement in engine performance. The "Volgovsky" switch has a higher breakdown voltage and a steeper high-voltage pulse front, which, they say, has a positive effect on starting characteristics and reduces the requirements for the quality of candles.
3. The higher voltage generated by the 131st increases the risk of breakdown of the distributor cap and reduces the reverse voltage margin for the output transistor.
4. The 13th switch is simpler, and therefore more reliable. It uses an ordinary high-voltage transistor as an output, which in itself is more reliable than the Darlington transistor used with the L497 chip. Especially at 50 watts dissipated on the collector during current stabilization.
5. The 131st switch ensures more efficient use of the energy of the onboard network. The average current through the coil in the most used speed range is less than the 13th. So, if your "gene" is dead, with the 131st you will go almost twice as far. And the coil will be colder.
6. It is easier to start the engine with the handle with the 13th. A spark is formed regardless of the speed of rotation of the HF!
7. Well, the last. If your native ignition system works quite well, there is no reason to replace the switch with a Volgovsky one. And if she has already "got you", try something more modern.

Judging by the materials of the conference, many UAZ owners changed the standard switch 13.3734 to "Volgovsky" 131.3734 or similar. At the same time, a lot of stories are told about how much the dynamics, economy, idle speed stability, etc. have improved.

I also "decided to try it, took the bottle, opened it" (c). The miracle, as expected, did not happen, since the engine was already working quite well, so it was decided to dig deeper and replace the sensations and impressions with more accurate data.

So, starting positions. There are two switches: native - 13.3734 and 94.3734, produced by "ELARA". There are diagrams of both, one from the manual, the other from articles. Datasheet for the L497 chip. Pointer ammeter and oscilloscope S1-94.

A decent amount of "information for reflection" (s) can be obtained by looking at the voltage waveform at the output of the switch. Therefore, the main efforts were directed to obtaining it for competing devices. I ask for pictures that show the output voltage of both switches. The time parameters correspond to approximately 1000 rpm. Let's start with native:

A spark is like a spark. Everything is in order - high voltage surge, gap breakdown, arc burning, its extinction after the energy in the coil is exhausted, after a while the switch turns on again and remains in this state until the next spark. The output transistor switch has two states - on and off. Moreover, the duration of the off state decreases with an increase in the number of engine revolutions (sparking frequency).
Those. almost all the time current flows through the coil, and if it is not further limited, it and the transistor key will have a bad time (based on the parameters of the coil, the current can reach 20 amperes with a tail). Well, yes, the authors of the ignition system took care of this, and provided us with a limiting resistor - a variator that limits the direct current through the coil at a level of about 7.5A. (It is a variator, apparently, because it has a tap for closing its part at start-up.)

Be curious about the dependence of the current through the coil on the engine speed. It turns out that the heaviest mode in terms of heat is idling. So, if your machine works for a long time at low speeds or at idle - the bobbin does not stay cold! Moreover, the variator is located below the reel, additionally heats it.
With the engine turned off, but the ignition on, the switch periodically spontaneously generates a spark, somewhat reducing the current consumption and making it easier to start the engine at very low speeds (in cold weather or from the handle). Let's count for dignity.

And here is the same voltage generated by the "Volgovsky" switch. It's smarter.
The cycle (phase 1) begins with the opening of the key. The current in the coil increases exponentially, tending to the above 20A. But does NOT reach them! Since the output transistor is transferred by the L497 control chip to the active mode (phase 2) and limits the current. Takes on the function of the variator. Variator NOT NEEDED! The transistor limits the current to 6A, providing a constant energy stored in the bobbin, and therefore given to the spark. The variator with this switch is HARMFUL! It does not allow the current, especially at low voltage in the on-board network during start-up, to reach the limit value and violates the stabilization of the pulsed current through the coil.

A little trouble - during the operation of the output transistor in the current stabilization mode, about 50 W of power is dissipated on it! Not for long, of course, but still ...
Finally, the transistor closes on a signal from the distributor sensor - a high voltage pulse and a spark are formed. The voltage pulse is higher than that of the 13th switch, but shorter. Most likely, this is due to the fact that they have capacitors of different capacities in parallel with the transistor. The 13th has 1uF, and the 131st has 0.1uF. But the areas under the half-wave are close, i.e. the energy is about the same. And the duration of the spark is almost the same as the 13th. At the end of the spark, the key does not think to open (phase 4). The commutator waits for phase 1 calculated by the control chip from the previous half revolution of the motor. Those. most of the time, the output transistor of the switch is closed. At least at low speeds.
Look at the dependence of the average current through the bobbin on the speed. Here everything is "exactly the opposite" in comparison with the 13th switch. XX is the easiest mode for the reel. Moreover, if the engine stalls, after about 1 second, the output transistor will be closed by the control chip. The consumption of the ignition system will be equal to the consumption of the control circuit - 50 milliamps ... But no more sparking without a signal from the distributor. If the engine rotates slowly, and the amplitude of the signal from the sensor is insufficient to trigger the shaper, you will be left without a spark!

A little about the L497 chip, invented by the glorious SGS Thomson. This is a specialized analog-pulse computing device, where the time parameters are set by capacitors. These are not the most accurate and stable radio elements.
The microcircuit has the following functions, partially mentioned earlier:

• Controlling the opening angle of the output transistor.
• Output current limitation.
• Output high voltage limitation.
• Turning off the output transistor in the absence of a signal from the sensor.
• Formation of a signal for a tachometer.
• Protecting itself from electrical overloads.

1. The dialectic is there. Each device has its own advantages and disadvantages. And both are not masterpieces of ignition engineering.
2. The energy of the spark generated by both ignition systems is approximately the same. So with good spark plugs, wires and a distributor, you should not expect a noticeable improvement in engine performance. The "Volgovsky" switch has a higher breakdown voltage and a steeper high-voltage pulse front, which, they say, has a positive effect on starting characteristics and reduces the requirements for the quality of candles.
3. The higher voltage generated by the 131st increases the risk of breakdown of the distributor cap and reduces the reverse voltage margin for the output transistor.
4. The 13th switch is simpler, and therefore more reliable. It uses an ordinary high-voltage transistor as an output, which in itself is more reliable than the Darlington transistor used with the L497 chip. Especially at 50 watts dissipated on the collector during current stabilization.
5. The 131st switch ensures more efficient use of the energy of the onboard network. The average current through the coil in the most used speed range is less than the 13th. So, if your "gene" is dead, with the 131st you will go almost twice as far. And the coil will be colder.
6. It is easier to start the engine with the handle with the 13th. A spark is formed regardless of the speed of rotation of the HF!
7. Well, the last. If your native ignition system works quite well, there is no reason to replace the switch with a Volgovsky one. And if she has already "got you", try something more modern.