JPS5819856B2 - Ninenkikanten Kajikichiyousouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention controls ignition timing based on the exhaust gas temperature and engine load of an internal combustion engine, reduces harmful components in the exhaust gas, and allows the exhaust gas purification device to work efficiently. This invention relates to an internal combustion engine ignition timing adjustment device.

Conventionally, manifold reactors, catalytic converters, ignition timing retarders, and the like are generally known as exhaust gas purification devices.

Among these, manifold reactors in particular are recently used without secondary air injection in engines with subchambers, etc.
Lean reactors are being reviewed.

This has the great advantage of being a simple system that does not require air pumps, control valves, etc.

The problem with this is that since lean combustion is performed, there is little CO in the exhaust gas, and the exhaust gas temperature is low, so the manifold reactor does not work effectively.

For this reason, HC reacts with 0□ in the manifold reactor and is oxidized to CO, causing a major problem in that more CO is produced than when the engine is exhausted.

To prevent this, the ignition timing should be adjusted at low idle speed (deceleration).
Methods such as retarding the temperature and increasing the temperature, or increasing the heat capacity of the manifold reactor (making it less likely to cool down), etc., have been taken.

However, these methods have many problems in terms of cost and cannot cope with the increase in engine load and the amount of exhaust gas passing through the manifold reactor per unit time.

The present invention has been made in view of the above-mentioned points, and is intended to constantly detect the exhaust gas temperature and engine load, and control the exhaust gas temperature based on the signals.

In other words, when the engine load increases and the amount of exhaust gas increases, if the exhaust gas temperature is lower than a predetermined temperature, the engine will be retarded until it reaches the predetermined temperature, and if it is above the predetermined temperature, it will be advanced, and if the exhaust gas temperature is lower than the predetermined temperature, it will be advanced. If it does, it will be delayed.

Alternatively, when the engine load decreases, if the exhaust gas temperature is higher than a predetermined temperature, the ignition timing is advanced until the predetermined temperature is reached, and if the exhaust gas temperature is below the predetermined temperature, the ignition timing is retarded. To provide an internal combustion engine ignition timing adjustment device that is compact, has a simple configuration, and has the great feature of being able to effectively operate an exhaust gas purification device such as a manifold reactor because the exhaust gas temperature is always maintained at an optimum temperature. The purpose is -.

Embodiments of the apparatus of the present invention shown in the drawings will be described below.

First, let's explain the general configuration. Figures 1 and 2
In the figure, 10 is the engine body, 11 is the combustion chamber, and 12
13 is an intake valve, 13 is an exhaust valve, 20 is an intake manifold, 30 is an exhaust manifold, 40 is an exhaust master near the exhaust valve outlet, a temperature sensor attached to the second hold 30, 50 is a manifold reactor, 200
300 is an engine load detector; 100 is an ignition interrupter that receives a signal from the determination circuit 200 and changes the ignition timing.

After combustion in the combustion chamber 11, the exhaust gas passes through the exhaust valve 13, the exhaust manifold 30, and the manifold reactor 50.
is discharged through the

Therefore, the temperature detector 40 and the engine load detector 300.4
= Exhaust gas temperature and engine load are detected and judgment circuit 2
00 determines the advance or retard angle and activates the ignition interrupter 1.
Controls the ignition timing of 00.

Next, details will be explained with reference to FIGS. 1 to 5.

101 is an ignition interrupter case of the engine, 102 is a camshaft that rotates in proportion to the rotational speed of the engine, and 103 is a camshaft 1.
This is an ignition cam cylinder rotatably supported on the 02.

A support plate 104 is fixed to the cam shaft 10, and a pin 107 is provided at the tip of an advance centrifugal weight 106 connected to the support plate 104 to engage with the ignition cam cylinder.

Therefore, as the speed of the engine changes, the cam cylinder 103 changes to the cam shaft 1.
Rotate relative to 02.

110 is a board fixed to the case 101, and the ignition interrupter 112 is pivotally supported by a shaft 113 on an annular moving plate 111 which is pivotally supported in its center hole, and the cam face 103 of the cam cylinder 103 and the sliding plate are provided in the center of the board. A sliding contact piece 114 is provided, and a movable contact 115 is provided at the tip.

116 is a fixed contact corresponding to the movable contact 11;
A spring 17 is attached to the ignition interrupter 112 so as to push the sliding piece 114 toward the cam surface 103A, and both springs are attached to the annular moving plate 111.

If contact 115116 is then disconnected, a spark discharge will occur at the engine spark plug, as is conventional.

118 is a connecting rod 1 attached to the annular moving plate 111.
The connecting rod 119 is connected to the driving rod 121 by the pin 120 at the pivot point 19.
is connected to.

Reference numeral 125 is a reversible motor, and its drive shaft 124 and cam 123 are coupled via a slip mechanism (not shown) consisting of a well-known friction clutch. The slipping of the friction clutch prevents excessive torque from being applied to the motor drive shaft 124.

Note that the motor may be stopped immediately at the cam stop position using a switch or the like without using a friction clutch.

The coil spring 122 is adapted to push the drive rod 121 towards the cam 123, and therefore the reversible motor 1
25 rotates forward as shown by arrow A, the annular moving plate 111 also rotates as shown by arrow B.
Since it rotates as shown in the figure, the ignition timing is delayed accordingly.

Next, the drive determination circuit 200 for the reversible motor 125 will be specifically explained, taking the engine speed as an example of the engine load.

Figure 5 shows ignition timing on the horizontal axis and exhaust gas temperature on the vertical axis.
This is a graph showing the relationship between ignition timing and exhaust gas temperature using engine speed as a parameter.

In general, advancing the ignition timing will lower the exhaust gas temperature and retard the ignition timing.
The exhaust gas temperature rises due to the cracks.

Furthermore, as the engine speed increases, the exhaust gas temperature also increases, but the amount of exhaust gas also increases.

Now, the engine speed is 200°rpm and the ignition advance is '.
CBTDC (BTDC indicates the cam closing angle before top dead center.

(the same applies hereafter), and the exhaust gas temperature at which the manifold reactor is efficiently purified is γ°C.

Next, when the rotational speed is lowered to 1100 orp while maintaining the same advance angle, the exhaust gas temperature drops significantly from γ°C to 1°C, and the purification rate of the manifold reactor etc. bottoms out.

Therefore, if the exhaust gas temperature is maintained at γ℃, then
It is necessary to delay the advance angle from C'BTDC to A' BTDC.

However, if the engine is dropped at 11,000 rpm, the amount of exhaust gas passing through the manifold reactor per unit time will decrease, so in order to maintain the self-purification rate, the exhaust gas temperature can be lowered to β℃. The lead angle can be advanced to B'BTDC.

As a result, it is possible to expect an increase in engine torque by one degree when A'BTDC is lowered.

Similarly, when the rotational speed becomes 300 rpm, the exhaust gas temperature becomes as high as ε°C, but if this continues, the torque will decrease even if the purification rate improves.

Therefore, in order to maintain the same temperature γ℃, the advance angle should be set to E”BTDC.
We will proceed to

However, when the temperature is maintained at γ° C., the amount of exhaust gas increases at 3000 rpm, so the purification rate by the manifold reactor decreases.

Therefore, in order to increase the exhaust gas temperature to the same purification rate, the advance angle is set to tD'BTDc.

In this way, the exhaust gas temperature and engine load are constantly detected and the ignition timing is adjusted to optimize purification by the manifold reactor.

Next, the ignition timing adjustment determination circuit 200 and engine load detector 300 will be explained.

The exhaust gas temperature signal from the thermocouple temperature detector 40 is input to the discrimination circuit 200 .

The discrimination circuit 200 includes resistors 211, 212°213.21
4. A non-inverting amplifier 210 composed of an amplifier 215;
Temperature detection circuit 2 composed of a resistor 221 and a comparator 222
20, a resistor 231° transistor 232, a back electromotive force absorption diode 233, and a movable contact 234 al
s 234 bt as fixed contacts 234a2, 234a
3,234b2, 234b3°, and a relay circuit 230 including a relay coil 234 that drives 3,234b2, 234b3°.

When the engine load detector 300 detects the rotation speed, the opening/closing signals of the ignition interrupter contacts 115 and 116 are detected by the engine load detector 30.
It's at 0.

The engine load detector 300 includes resistors 31L312, 313,
An ignition interrupter signal waveform shaping circuit 310 consisting of a 314° capacitor 315 and a transistor 316, and a resistor 32
2.323, a monostable circuit 320 composed of a capacitor 321, and a transistor 324, and an integrating circuit 330 composed of a resistor 332 and a capacitor 331.

401 is an ignition coil, 402 is a spark plug, 40
3 is a switch, and 404 is a power supply.

The exhaust gas temperature signal is amplified by non-inverting amplifier 210 to increase the output voltage linearly with temperature and is applied to one of the input terminals of comparator 222.

- The opening/closing signals of the power and interrupters 115 and 116 are provided by the shaping circuit 31.
0, the signal is shaped into a square wave, and the monostable circuit 320 converts it into a pulse with a constant width.

Therefore, a number of pulses corresponding to the rotational speed are sent to the integrating circuit 330 to charge the capacitor 331, and the terminal voltage thereof increases as the rotational speed increases.

The temperature detection circuit 220 compares the exhaust gas temperature signal and the rotation speed signal, and when the temperature is below a predetermined temperature due to the engine load, the output of the temperature detection circuit 220 is 0 level, and when it is above the predetermined temperature, the output is level.

When the level is 0, the transistor 232 of the relay circuit is OFF.
The reversible motor 12 is in the F state and the contacts 234at-234a3 and 234bl-234b3 are connected.
5 rotates forward and retards the ignition timing.

When the power is on, the transistor 232 is turned on, and the contacts 234al-234a2 and 234bl-2
34b2 is connected, the reversible motor 125 rotates in reverse, and the ignition timing advances.

In this way, the exhaust gas temperature is maintained at a temperature at which exhaust gas purification is performed optimally even if the engine speed changes.

Although the engine speed has been taken as an example of the engine load above, it goes without saying that intake negative pressure, intake air amount, etc. can also be used as parameters easily by using an appropriate detector.

As described above, in the present invention, the temperature detector detects the exhaust gas temperature, the engine load detector detects the engine load state, and the temperature detector signal and the engine load signal are provided to the discrimination circuit. The output of the discrimination circuit advances or retards the ignition timing control means such as a reversible motor that performs advance/retard control of the ignition interrupter (distributor) to achieve a set temperature that changes in response to this engine negative signal. As a result, excellent effects can be achieved as described below.

(1) By simply equipping an exhaust gas temperature detector, engine load detector, reversible motor, and discrimination circuit, the exhaust gas temperature can be controlled to the optimum temperature for purification according to the engine load, not only during warm seasons but also during normal operation. , HC and NOX, harmful components of exhaust gas, can be easily reduced in the engine.

(2) At startup, since the exhaust gas temperature is low, the ignition timing can be retarded, and warm-up can be carried out quickly without significantly increasing the rotational speed of the engine.

(3) Since the control method is performed in an analog manner, unlike the case where the ignition timing is controlled by the ON-OFF method used conventionally, the engine drive is smooth and the driving feeling is good.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing the overall system of the internal combustion engine ignition timing adjustment device according to the present invention, FIG. FIG. 3 is a sectional view of essential parts showing an example of an ignition interrupter used in the device of the present invention, and FIG. 4 is a cross-sectional view taken along line CC' in FIG. 3.
FIG. 5, which is a sectional view of the main part along the line, is a graph showing the relationship among the ignition timing, exhaust gas temperature, and engine speed of the internal combustion engine. 40...Temperature detector, 100...Ignition interrupter, 125...Reversible motor, 200...
...Discrimination circuit, 300... Engine load detector.

Claims (1)

[Claims] 1. A temperature detector that detects the exhaust gas temperature of the internal combustion engine;
an engine load detector; ignition timing control means for advancing or retarding ignition timing of the internal combustion engine relative to normal operation; a temperature detector signal from the temperature detector; and an engine load signal from the engine load detector. and a discrimination circuit for determining advance or retard operation of the ignition timing control means to achieve a set temperature that changes in accordance with the engine load signal.