FR2483528A1 - CIRCUIT IGNITION AND COLD START OF FOUR-TIME CAR ENGINES, FOR 12 V POWER SUPPLY - Google Patents

Abstract

The circuit arrangement according to the invention for the ignition and cold starting of 4-stroke vehicle engines with a 12V network, and for increasing the voltage for a cold starter (A), generates an increased DC voltage from a DC voltage. In order to compensate for voltage drops, and to generate an effective high-power spark without modifying the motor vehicle ignition circuit, a control electrode (3) of the cold starter (A) is connected to the unearthed terminal (30) of the starting magnet (E) and a contact (4) of the same is connected to the vehicle ground potential, and the cold starter (A) receives the energy required for continuous operation of the ignition transformer (B) via two terminals (1, 2). The circuit preferably contains silicon semiconductors.

Description

The invention relates to a circuit for forming a voltage of 12 - 14 V for

starting engines during a cold start and when the battery voltage

is greatly reduced.

  The rotation of the electric starter requires high power. As a result, the voltage, when cold, of a low-capacity, discharged battery can be reduced to such an extent that the spark necessary for the explosion (for combustion) of the mixed; in other words, the required power is not obtained. In the case of a discharged battery - significantly discharged - this phenomenon is even more marked, and repeated starts-up can

  lead to a complete discharge of the battery.

  It has been proposed to use ignition transformers - designed for a lower operating voltage -,

  the normal operation of these transformers being-

obtained through additional resistances-, which are-

  short-circuited at startup. This solution results in a damping effect on the oscillations in the ignition circuit, and the performance therefore becomes poor. Coils with divided primary circuit, operating at start-up with a higher voltage ratio

high, have not proven to be a better solution.

  The recently used double batteries, the so-called "tandem" batteries known as the TO-GA with two batteries in a single block, the lower capacity battery supplying the energy necessary for the ignition circuit, do not constitute either better solution, since a double charge is necessary and that,

at startup, the use of a switch is essential

thinkable.

  The most recently proposed solutions -

  for example, capacitors with transistors and thyristors activated by converter (oscillator) or any other device making it possible to stabilize the supply voltage at ignition - do not have the disadvantages previously listed; but, given their stabilizing role, they cannot take into account the fact that, in unfavorable conditions, it is necessary to form a stronger spark with a

increased power.

  The ignition in vehicles must be

  fully reliable during operation. The electronic systems used until now often fall

  broken down due to their complexity.

0 As a result of their design, the majority of electronic ignition circuits must include a

switch- with manual control allowing to pass immediately

  diat in normal ignition if necessary. It must also be taken into account that the electronic ignition circuits operate continuously and,

  as a result, break down more frequently.

Given these problems, a solution must be found, by which one can compensate for the drop in voltage due to repeated starts and obtain a high ignition power, without it being necessary.

  to design a new ignition circuit, interrupting

  pant the primary circuit of the ignition transformer

to insert the device.

  The main objective pursued during the study was that the normal ignition system could operate continuously without disturbance in the event of failure of the equipment; were then studied the questions of cost, the device having to be of a cost

  acceptable compared to electric ignition systems

tronic known, produced in an aesthetic form with advantageous geometric dimensions, and

maintenance to be removed.

The new circuit according to the invention includes a DC / DC converter to bring the voltage to 12-14 V during the period when a voltage drop occurs - due to the rotation of the starter motor, hereinafter also designated " automatic starter ". To this end, it suffices that the starter motor can carry out as many revolutions as is necessary to effect a single interruption by means of the ignition switch. This implies that an effective spark is formed capable of exploding the mixture in the compressed space of the cylinder; from

  from there, the operation becomes permanent.

The needs listed can be met so that the brief additional increase

desired voltage is provided by a generator of -

low internal resistance voltage, in series with the original ignition supply voltage, this,

during the period when the starter motor is running.

  It should be noted that the voltage generator is designed such that it includes silicon semiconductors; as is known, these semiconductors have good thermal stability, and it will be noted that the

  system can oscillate with a control current ex-

  very low (300-400 mA). A very good energy efficiency can be obtained despite the small geometric dimensions of the DC / DC converter which is at

  the basis of the invention. Mounted in its case, the

  cooked according to the invention - which will subsequently be designated - "cold starter" - can be installed anywhere 4.

of the engine compartment.

  Given the series connection (booster circuit), the power required by the transformer

  continuous / continuous according to the invention is substantially-

  lower than the required power, by the circuit

complete ignition.

  The boosted primary circuit voltage appearing at the output terminals of the assembly, doubled (compared to the instantaneous battery voltage), allows fast starting of vehicles with high operating safety, even in cold weather, by example when the ambient temperature is -250C, assuming that the oil and petrol used

are of correct quality.

  The rest of the description relates to a

preferred embodiment of the invention, with reference to the accompanying drawings which represent FIG. 1, the diagram of the starter, FIG. 2, the connection of the starter,

  20. figure 3, the connection with the references

  digital and literal references in use in industry

automotive (Bosch system).

  The power output 1 of the cold starter A is connected to point 15 of the ignition coil B (Figures 1 and 2), point 2 being connected to point 15 of the ignition switch D (Figure 3). Point 3 of

  cold starter A has several connection possibilities

ment, and can be connected either to terminal 30 of winding E of the starter relay, or to point 50 of the automatic starter motor F, or to point 30h of contact H of the starter relay; by using these different connections, a control voltage can be obtained which gives the maximum output voltage. Point 4 of the cold starter is connected to the chassis of the

  vehicle, i.e. with mass potential.

sition and connection of elements Cl, C2, C3, L3, Ri, R2 and T whose role is known and which are used in the apparatus, are illustrated in FIG. 1, the contact breaker C and the ignition capacitor being illustrated in FIGS. 2 and 3. The device operates as follows: The voltage is applied to the cold starter A and to the electromagnet E by actuation of the ignition switch D. Consequently, the winding E switches the starting motor automatic F to battery G; - the automatic starting motor starts to run and

  drives the contact breaker C. Simultaneous-

  voltage is applied to the oscillator of the

cold starter via coil LI-

  (Figure 1) and the control electrode 3. The oscillator begins to oscillate and the increased voltage arrives by

through the coils L2, LÀ of the primary-circuit

  and rectifier Di, on the primary circuit 15 of the

ignition coil B. Given the repeated operation

  of the contact breaker-C, a voltage is induced-

  in the secondary circuit, the amplitude of this voltage corresponding to the ratio of the ignition transformer B.

  There is therefore a spark of great power.

- With the engine started, the switch

  ignition D - having been released from the off position

  automatic start-up - permanently supplies voltage to the primary circuit of the ignition coil B, via point 2 of the cold starter,

the coil L2 and the diode Di.

  The semiconductors of the cold starter, the

  diode Di and the transistor T, are elements suscep-

tibles to operate at a high intensity, ensuring

- 2483528

perfectly reliable operation, of dimensions

advantageous, and of a recent type.

  The long useful life and the high reliability

operational reliability are due to the fact that, despite its advantageous small dimensions and its relatively low requirements for control current, the starter

when cold is capable of transferring extreme power

high. At start-up, it immediately supplies twice the output voltage of the battery, even if the battery voltage is reduced to 8-9 V for example, so much so that the automatic starter motor turns

  with difficulty, while being capable, however, of provo-

  at least one opening of the contact breaker.

The size of the circuit is small, as well as its weight.

  - In another preferred embodiment in accordance with the invention, the cold starter control electrode can be connected - at the same time as the automatic start circuit - to the contact points 30, -30h, 301 which become positive, or at point 5.0-o passes a

  -high current, or at a selected point near the de-

cold feeder A, so that the minimum tension required

  for oscillation is always available. The main

  pal advantage of the cold starter according to the invention

  is that it can be made in a very aesthetic form

tick, with advantageous geometric dimensions and low weight. It requires no maintenance, its

  operating reliability is high, its re-

comes is weak and it adapts perfectly to others

vehicle electrical components.

  In an embodiment according to the invention, the transformer of the oscillator included a ferrite core of high magnetic permeability, so that despite the small dimensions, this transformer

  ensured the transfer of a high power.

  The cold starter can perfectly be adapted to the ground polarity of the vehicle, so that, for a negative polarity, the transistor T is of the NPN type, and, for a positive polarity, the transistor T

  is of the PNP type, the diode Di being connected accordingly

quence.

RV; VENDICATI ONS

1. Ignition and cold start circuit of four-stroke car engines for 12V power supply, allowing to increase the voltage during cold starts to obtain a higher direct current from the initial direct current, characterized in what the elect

  cold start (A) control unit (3) is connected

  strung to the terminal not to the ground of the winding (i) of the

  starting relay, in that the contact (4) of this

the cold starter is connected to the ground potential and

that the cold starter (A) receives the necessary energy

  for the permanent operation of the power coil

light (B) and transmits it through its connections (2, 1).

  2. Circuit according to claim 1, character-

  rised in that the circuit includes silicon semiconductors making it possible to form a spark. efficient, stable and reliable for combustion chambers, in a wide range of ambient temperatures between - 25C and + 700 C and so that the increase in

voltage is only possible during the start-up

automatic age.

3. Cold starter circuit according to the res-

  dications 1 and 2, characterized in that, simultaneously with the automatic start, the control electrode (3) can be connected at any point becoming positive (30, 30h, 301, 50) in order to obtain the. maximum voltage of

  command required for oscillation.

AT*