WO2006121368A2

WO2006121368A2 - Ignition system for an internal combustion engine

Info

Publication number: WO2006121368A2
Application number: PCT/RU2006/000204
Authority: WO
Inventors: Mikhail Panteleimonovich Brizhinev
Original assignee: Institute Of Applied Physics Ras
Priority date: 2005-05-05
Filing date: 2006-04-25
Publication date: 2006-11-16
Also published as: CN100575696C; WO2006121368A3; RU2287080C1; CN101213366A; EP1887217A2

Abstract

The invention relates to the automobile industry, in particular to spark ignition systems for internal combustion engines. Said invention makes it possible to improve the engine performance reliability, in particular at low-temperature and high-humidity conditions. The ignition coil of the ignition system is embodied in such a way that the self-surge impedance ρ of an oscillating circuit formed in a secondary coil by inductance and effective capacitance, taking into account a current leakage, lies within a range of 1.4•Ubreak/ Imax<ρ<4,5•Ubreak/ Imax, wherein Ubreak is a minimum voltage value in a discharge gap at which the break-down is guaranteed, Imax is a maximum sparking current at which the spark is not converted into a low-voltage arc discharge. The self-surge impedance value ρ from said gap is adjusted with the spark discharge parameters (break-down voltage, discharge current), thereby reducing undesirable energy loss in the ignition system and increasing a spark power.

Description

Ignition system of an internal combustion engine

Technical field

The invention relates to the automotive industry, namely, to electronic ignition systems of internal combustion engines (ICE). The invention can be used in spark ignition systems for more reliable engine operation at low temperatures and / or high humidity, as well as with not very high quality air-fuel mixture.

State of the art

A device is known for increasing the plasma volume of a spark in a spark plug (US Pat. RU 2171909, M.kl.7 F02PZ / 04, F02PZ / 08, publ. 2001). This device contains a series LC circuit connected in parallel with the spark gap directly near the spark plug to eliminate the influence of the high-resistance secondary circuit wire of the ignition coil. The device, extending the burning time of the spark by 8-10 times, increases its volume by 3-4 times, increases the ionizing and thermal effects. This known device solves the problem of increasing the spark current, but additional elements are introduced into the circuit. The main disadvantage of such an ignition system is the high wave impedance of the oscillation circuit p ~ IMOM formed by the secondary winding of the ignition coil and the effective capacitance in the high-voltage circuit of the ignition coil, which is easily shunted by the leakage resistance in this circuit.

To obtain the necessary, adjustable in time, the duration of the continuous discharge allows the relaxation-vibrational system of electronic ignition of the internal combustion engine (US Pat. RU 2054575, Mcl 7 F02PZ / 04, publ. 1996). Two additional diodes are introduced into the internal combustion engine ignition system, which contains a thyristor-capacitor block of a high voltage, a low-voltage block of a voltage boost and a transistor switch in the primary circuit of the ignition coil. The first diode is connected in parallel to the thyristor and capacitor circuit and connects the thyristor anode to the voltage boost unit. In this case, the second diode connects the midpoint of the thyristor-capacitor circuit with the output of the primary winding of the ignition coil. The ignition system creates relaxation oscillations, which allows you to maintain a continuous discharge current for the right time and forms a wide initial flame front. The ignition system provides an efficient combustion process of the fuel mixture and increases fuel economy. The disadvantage of this system is the introduction of additional elements. Using standard existing ignition coils does not solve the problem of high wave resistance p of the oscillatory circuit of the secondary coil. This reduces the reliability of operation and starting the engine in adverse conditions due to shunting of the discharge gap of the candle with leakage resistance.

Facilitate starting the engine in adverse conditions, especially in winter, allows the spark ignition system of the internal combustion engine, known according to patent RU 2107184, M. cl. 7 F02PЗ / 04, publ. 1998. This ignition system contains a series-connected voltage converter, voltage doubler, voltage stabilizer, chopper, included in the primary winding of the ignition coil. And in the secondary circuit of the ignition coil before the discharge gap of the spark plug, a larger additional spark gap is introduced. This design reduces the undesirable effect of leakage currents, with almost all the energy spent on the formation of a spark in the spark plug. But this does not exclude the capacitive phase of the discharge, when most of the current energy in the discharge gap goes to the destruction of the spark electrodes. Another disadvantage is the complication of the circuit, the introduction of a number of additional blocks to stabilize the voltage, and additional erosion of the material in the added spark gap.

The largest number of common elements with the proposed ignition system contains a standard ignition system (see, for example, S.V. Akimov, Yu. P. Chizhov ((Electrical equipment of automobiles)). Textbook for universities, pp. 188-191. Edition. “3a en - Lem ", 2001), which is selected as the closest analogue (prototype). Ignition system - the prototype contains a power source, a switch, an ignition coil, consisting of a primary and secondary winding and magnetic circuit, a spark gap, as well as capacities and active resistances in the primary and secondary winding circuits of the coil. The disadvantage of the standard ignition system is its unreliable operation. Soot and moisture on the spark plug insulator, dirt and condensation in the ignition distributor and on the high-voltage wires lead to interruptions in the engine or a complete failure of the entire ignition system. Especially often, such situations arise when operating a car in winter at low temperatures. The analysis shows that in typical ignition systems a significant part of the energy stored in the ignition coil is lost during the formation of a high voltage on the spark plug and when the discharge current flows in it. The main losses are associated with leakage currents in the high voltage circuit and, in addition, there are significant induction losses in the magnetic circuit of the coil and during the course of the capacitive phase of the discharge.

Disclosure of invention

The problem solved by the present invention is to increase the power of the spark and the reliability of the sparking of the ignition system by eliminating the "non-productive" losses by matching the wave impedance p of the circuit formed by the inductance and capacitance included in the ignition system with the parameters of the spark discharge - breakdown voltage and discharge current.

The technical result is achieved by the fact that the proposed ignition system, as well as the prototype, contains an ignition coil consisting of primary and secondary windings and a magnetic circuit, and a spark gap included in the secondary circuit of the ignition coil.

New in the developed ignition system is that the ignition coil is made in such a way that the wave resistance p of the oscillatory circuit formed by the inductance and effective capacitance in the secondary winding, taking into account leakage currents, lies in the range:

U _samples - the minimum voltage value at the discharge gap, at which a breakdown is guaranteed, I _add - the maximum allowable spark discharge current. The maximum value of the discharge current is limited by the condition that the combustion process of the high-voltage spark switches to the low-voltage plasma-arc discharge mode, in which the main arc energy is not used to heat the TBC, but to destroy the spark electrodes.

In the particular case, it is advisable to exclude losses during the capacitive phase of the discharge, in the manufacture of the windings of the ignition coil, to make them with an increased magnetic flux scattering flux, for example, in the form of a biscuit. In another particular case, in order to reduce eddy current losses, it is advisable to produce the magnetic circuit of the ignition coil from a material with low specific losses, for example, from transformer iron, designed for a frequency of 400 Hz. During the formation of high voltage, uncontrolled energy losses are associated with leakage currents. Calculations show that the most typical value of the wave resistance of an ignition system with a standard coil is p ~ 1 MΩ. In the presence of leakage currents in such a system through a leakage resistance equal to the wave one, the voltage across the spark gap is almost halved, which leads either to a failure of the ignition system or to a significant decrease in the spark energy.

In the process of burning a spark, the main energy loss is associated with the thermal conductivity of the fuel-air mixture, and with a low power of the spark, even with an increase in its duration, the fuel-air mixture may not ignite. The provision of the claimed technical result can be explained as follows.

The solution of the wave equation for a parallel oscillatory circuit, which is the secondary circuit of the ignition system, can be written as the voltage in the circuit: t

2-rym-C

U = U - e ₇ (+ i-ω-ή U = U _a - e '^" - ^ (1) where U _a is the amplitude value of the voltage, ω and t are the frequency and time, respectively, and L, C, R _yx are the parameters of the contour in the conventional notation.

After turning off the key in the primary circuit of the ignition coil, the voltage

reaches its maximum value at R _π = p at the time instant * _max ^{= 1} JeT • A necessary condition for the appearance of a spark in the spark plug at THIS moment is

Umax ≥ U _np , WHERE

2 _t

P '' max

From equation (2) for leakage resistance, at which the condition of the breakdown of the discharge gap is maintained, we find: P '^ max

L _™ ≥

^USH ~ 2 L s ^{Idop 'p *} ^

Sample

From equation (3) we find the value of the wave impedance p at the minimum value of the leakage resistance:

Considering an acceptable condition for reliable operation of the ignition system at Rug, increased by 1.5 times relative to the minimum, for wave resistance p we find the range of acceptable values:

Given that the typical values of U _p0b are ~ 10–15 kV, I _dop is

~ 0.3 A, we obtain the interval of numerical values of p corresponding to condition (5):

50 kΩ <p <180 kΩ. (5a)

The leakage resistance at which the operability of the ignition system is maintained is found from the same equation (3) and it can be shown that its minimum value is equal to the wave impedance, that is, Ry ₁ - = p.

Brief Description of the Drawing FIG. 1. The equivalent circuit of the proposed ignition system is shown.

The best embodiment of the invention

The ignition system contains a power source 1, active resistance 2, a capacitor 3 and a switch 4 included in the primary circuit 5 of the ignition coil. The ignition coil also includes a magnetic core, made in the form of a magnetic core 6, and a secondary winding 7, the circuit of which contains its own inductance 8 of the secondary winding 7, a capacitance 9, counted from the primary circuit, leakage resistance 10 and the discharge gap 11 of the spark plug.

As a power source 1, a rechargeable battery is used, the resistance 2 is the active resistance of the primary circuit. The ignition coil is made in such a way that the transformation ratio is the value of K "15 ÷ 3. In this case, we obtain a system with wave impedance of about 100 kOhm corresponding to the calculated one (4). The maximum voltage in the primary winding 5 of the ignition coil reaches 1000 ÷ 1500 V, which increases the requirement for the selection of the element base for the switch 4. The magnetic core 6 of the ignition coil can be made of material with low specific losses, for example, of transformer iron, designed for working frequency of 400 Hz.

The secondary winding 7 can also be made in the form of a biscuit. In this case, the self-inductance 8 of the secondary winding 7 (not connected with the primary magnetic flux) limits the spark current and eliminates losses during the capacitive phase of the discharge.

Based on the requirement to accumulate a certain energy in the system necessary for the formation of a spark, we choose the parameters of the coil the same as for a serial ignition coil of industrial manufacture. In the case of a specific implementation, the primary coil inductance 5 of the ignition coil is L 4 4 mH, the current in it is I I 6 ÷ 8 A, the capacitance of the capacitor 3, which protects the electronic switch (switch 4) from voltage overload C 0,1 0.1 μF .

The proposed ignition system shown in FIG. 1, operates as follows: when switch 4 is turned on, the current flowing from source 1 appears in the primary winding 5 of the ignition coil, through the primary winding 5 of the coil and switch 4. When the current reaches the maximum allowable value, enough energy is stored in the coil to form subsequent spark discharge candles. When turned off by a signal from the crankshaft position sensor (not shown) of the switch 4, the current of the primary winding 5 charges the capacitor 3, inducing a high voltage in the secondary winding 7. When the voltage in this circuit is sufficient for the breakdown of the spark gap 11, a breakdown occurs and a current begins to flow through the secondary winding 7 of the ignition coil. This current is composed of the current of the ignition coil itself and the discharge current of the capacitor 3, which is converted into the secondary circuit of the ignition coil into a capacitance 9 by the formula C ₂ = C JK ² , where K is the ratio of the number of turns in the secondary winding 7 of the coil to the number of turns in primary winding 5 of the ignition coil. The use of a modern element base in the manufacture of an electronic key (switch 4) and an ignition coil with a changed ratio of turns in the primary 5 and secondary 7 windings made it possible to obtain an ignition system with a low wave impedance p ~ 100 kOhm corresponding to condition (5), significantly less sensitive to currents leakage, and significantly increased spark power with an increased spark discharge current up to I _dop ~ 0.3 A.

An ignition system with the declared properties is obtained with constant energy consumption (the maximum current of the ignition coil). The system turns out to be less sensitive to leakage currents compared to known analogues, since the value of leakage resistance 10 almost always remains greater than the wave impedance p of the secondary winding circuit 7 and cannot bypass it, which eliminates "non-productive" losses, thereby solving the problem .

A feature of the operation of the ignition system according to claim 2 of the formula is the limitation of the spark discharge current due to an increase in the magnetic field scattering flux compared to analogs, for example, due to the manufacture of the secondary winding 7 of the ignition coil in the form of a biscuit, which eliminates losses during the capacitive phase .

A feature of the operation of the ignition system according to claim 3 of the formula is that during the formation of a high-voltage voltage, energy losses (heating of the magnet wire) are significantly reduced due to the manufacture of core 6 of the coil from transformer iron with low specific losses.

Tests of the ignition system, made as indicated in the specific implementation example on page 6, confirmed the high stability of sparking in candles, which preserved their operability even with a car mileage of about 100 thousand km. The presence of soot, gasoline and antifreeze on the spark plug insulator did not affect the stable operation of the engine.

The increase in discharge energy provided by the developed ignition system leads to a more complete combustion of the fuel mixture, and thereby reduces the toxicity of the exhaust. Industrial applicability

The engine ignition system developed is made on the basis of a modern element base (components). The number of turns of the secondary winding of the ignition coil was ~ 2000, which in serial production should reduce its cost, since usually this number lies in the range of 16-40 thousand turns.

Currently, 3 samples of the developed engine ignition system have been tested on cars of various brands, which have shown high efficiency of ignition of the fuel-air mixture.

The engine ignition system developed is ready for mass production.

Claims

Claim

1. ICE ignition system, comprising an ignition coil consisting of a primary and secondary windings and a magnetic circuit, and a discharge gap included in the secondary circuit of the ignition coil, characterized in that the ignition coil is made in such a way that the wave impedance p of the oscillating circuit, formed by inductance and effective capacitance in the secondary winding, taking into account leakage currents, lies in the range:

U _sample - the minimum voltage value at the discharge gap, at which a breakdown is guaranteed,

I _add - the maximum permissible spark discharge current at which the spark does not go into a low-voltage arc discharge.

2. The ignition system according to claim 1, characterized in that the windings of the ignition coil are structurally designed with an increased magnetic flux scattering flux, for example, in the form of a biscuit.

3. The ignition system according to claim 1 or claim 2, characterized in that the magnetic circuit of the ignition coil is made of material with low specific losses, for example, from transformer iron, designed for a frequency of 400 Hz.