JPH06185444A - Ignition device for spark ignition type engine - Google Patents

Abstract

(57) [Summary] [Structure] The ignition device of a spark ignition type engine is configured as follows. The ignition control device 4 can detect the engine operating state based on the detection of the intake negative pressure and the engine speed. Then, based on the fact that the ignition control device 4 detects that the engine operating state is in the partial load region, the ignition control device 4 stops the auxiliary ignition by the auxiliary spark plug 3 in the partial load region. [Effect] In the partial load region, the unnecessary auxiliary ignition by the auxiliary ignition plug 3 is stopped, and the single ignition is performed only by the main ignition plug 2. In the case of single ignition, the NO _x emission concentration becomes lower than in the case of 2-plug ignition. In this way, the NO _X emission concentration becomes low in the partial load region where the operating time is long, so that the total NO _X emission amount is significantly reduced. Moreover, since unnecessary auxiliary ignition is not performed in the partial load region, the life of the auxiliary ignition plug 3 is not unnecessarily shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition device for a spark ignition type engine, and more particularly to an ignition device capable of adjusting an ignition state according to an engine operating state.

[0002]

2. Description of the Related Art As a prior art of an ignition device for a spark ignition type engine, there is one having a basic structure similar to that of the present invention.
That is, there is a structure in which a main spark plug and an auxiliary spark plug are provided in a combustion chamber, both of these spark plugs are linked to an ignition control device, and two-plug ignition is performed by both spark plugs in the combustion chamber.

The two-plug ignition has an advantage that the ignition stability is improved as compared with the case of single ignition. Further, since the combustion speed is higher than in the case of single ignition, there is also an advantage that the output performance is improved. Therefore, this type of ignition device is an effective means for solving these problems in a lean burn type or exhaust gas recirculation type combustion device that leaves problems in ignition stability and output performance.

Normally, the two-plug ignition is performed with a predetermined ignition timing difference, and this ignition timing difference takes into consideration the trade-offs of the performances of improving output performance and reducing NO _X emission concentration. It is set. Incidentally, the smaller the difference in the ignition timing, the output performance increased burn rate increases, on the other hand, the discharge concentration of N0 _X increasing maximum combustion temperature tends to be higher.

By the way, in the conventional ignition device, as shown in FIG. 3, in all operating states, two-plug ignition is always performed with a constant ignition timing difference. Moreover, this ignition timing difference is usually determined on the basis of a size that can secure the required output in the full load region (when the engine speed is 1800 rpm, the crank angle is about 30 °).

[0006]

The above-mentioned conventional techniques have the following problems. When the two-plug ignition is performed, NO _{X is} more than that in the case of single ignition.
However, there is an advantage that the output performance is higher than in the case of single ignition. Therefore, starting region requiring high output, the entire load range, second plug ignition in the overload region is the expense to tolerate the increased emission concentration of NO _X, the resulting benefits that can ensure a high output required. However, the second plug ignition in not requiring part-load region of high output, simply only disadvantage the growing emission concentration NO _X.
According to this aspect, the above prior art, performed unnecessary second plug ignition in the partial load range, thereby increasing the discharge concentration of the NO _X in the long part load region of the operating time, total emission of the NO _X This means that the amount has been greatly increased. In addition, the life of the auxiliary spark plug is unnecessarily shortened by unnecessary 2-plug ignition.

If the ignition timing difference between the two plugs is reduced, the output performance tends to be improved. Therefore, in the overload region and the starting region, which require higher output than the full load region, it is desirable to adjust the ignition timing difference to be smaller than that in the full load region to enhance the output performance. However, in the above-mentioned conventional technique, the ignition timing difference is set to a magnitude based on the output performance in the full load region, and since the ignition timing difference is maintained in all operating states, in the overload region and the starting region. Sufficient output was not obtained, engine stall was likely to occur in the overload region, and starting performance was low.

An object of the present invention is to provide an ignition device for a spark ignition type engine that can adjust the ignition state according to the engine operating state.

[0009]

Means for Solving the Problems The first invention to the third invention are
As illustrated in FIG. 1 (A), the main ignition plug 2 and the auxiliary ignition plug 3 are provided in the combustion chamber 1, both ignition plugs 2 and 3 are linked to the ignition control device 4, and the combustion chamber 1 An ignition device for a spark ignition type engine, which is configured to perform two-plug ignition by both ignition plugs 2 and 3, is characterized by the following.

That is, in each of the first to third inventions, as illustrated in FIG. 1A, a negative pressure sensor 5 for detecting an intake negative pressure and a speed sensor 6 for detecting an engine rotation speed are provided. The negative pressure sensor 5 and the speed sensor 6 are made to cooperate with the ignition control device 4 so that the ignition control device 4 can detect the engine operating state based on the detection of the intake negative pressure and the engine rotation speed.

Then, in the first invention, as illustrated in FIG. 1B, the ignition control device 4 detects that the engine operating state is in the partial load region, and The auxiliary ignition by the auxiliary ignition plug 3 in the partial load region is stopped.

In the second aspect of the invention, as shown in FIG. 2B, the ignition control device 4 is based on the fact that the ignition control device 4 detects that the engine operating condition is in the overload region.
However, the ignition timing difference between the two plugs in the overload region is made smaller than the ignition timing difference in the full load region at the same engine speed.

In the third invention, as shown in FIG. 1 (B), the ignition control device 4 detects that the engine operating state is in the starting region, and
The ignition timing difference between the two plugs in the starting range is set to be smaller than the ignition timing difference in the full load range at the same engine speed.

[0014]

[Operation and effect of the invention]

(First Invention) As illustrated in FIG. 1B, in the partial load region, unnecessary auxiliary ignition by the auxiliary ignition plug 3 is stopped and only the main ignition plug 2 is ignited. In the case of single ignition, the NO _x emission concentration becomes lower than in the case of 2-plug ignition. In this way, the NO _X emission concentration becomes low in the partial load region where the operating time is long, so that the total NO _X emission amount is significantly reduced. Moreover, since unnecessary auxiliary ignition is not performed in the partial load region, the life of the auxiliary ignition plug 3 is not unnecessarily shortened.

(Second Invention) As shown in FIG. 1B, in the overload region, the ignition timing difference is made smaller than in the full load region, so that the output performance in the overload region is the full load region. Higher than in the case of. Therefore, a high output can be secured in the overload region, and engine stall is unlikely to occur. In order to make the ignition timing difference smaller than that in the full load range, NO
_Although the emission concentration of _X is higher than that in the full load range, the operating time in the overload range is usually short, so NO
The total increase in the amount of _X emissions is slight, and there is no actual harm in terms of exhaust gas measures.

(Third invention) As illustrated in FIG. 1B, in the starting region, the ignition timing difference is made smaller than that in the full load region. Therefore, when the output performance in the starting region is the full load region. Higher than. Therefore, high output can be secured in the starting region, and the starting performance is improved. Since the ignition timing difference is made smaller than in the full load range, the NO _X emission concentration becomes higher than in the full load range. However, since the operating time in the starting region is usually short, the increase in the total amount of NO _x emission is small, and there is no actual harm in terms of exhaust gas measures.

[0017]

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram for explaining an ignition device of a spark ignition type engine according to an embodiment of the present invention, and FIG. 1 (A) is a schematic diagram of the engine,
FIG. 1B is a graph showing the relationship between the engine operating state and the ignition state when the engine rotation speed is 1800 rpm. FIG. 2 is a graph showing the relationship between the intake negative pressure and the engine operating state when the engine rotation speed is 1800 rpm.

This engine is a spark ignition type three-cylinder gas engine having the following structure. As shown in FIG. 1 (A), a piston 9 is fitted inside a cylinder 8, and the piston 9 is interlockingly connected to a crankshaft 11 via a connecting rod 10. A combustion chamber 1 is formed in the cylinder 8 and an intake passage 12 and an exhaust passage 13 are connected to the combustion chamber 1. A venturi 14 is provided in the intake passage 12, and a throttle valve 15 is arranged downstream thereof. A gas cylinder 16 is connected to the venturi 14. The throttle valve 15 is linked to a speed control lever (not shown) via a governor device (not shown).

The structure of this engine ignition device is as follows. Main spark plug 2 and auxiliary spark plug 3 in combustion chamber 1
And the both ignition plugs 2 and 3 are linked to the ignition control device 4 via the ignition coil 17. The ignition control device 4 is a microcomputer. A battery 18 is connected to the ignition control device 4. A disk-shaped ignition instruction rotor 19 is externally fitted and fixed to the crankshaft 11,
The ignition instruction detection sensor 20 is exposed to the outer periphery of the sensor and is linked to the ignition control device 4. Ignition instruction rotor 19
Has a single starting point setting projection 21 with a short circumference on its outer circumference.
And three ignition indicating protrusions 22 having a long circumference. The three ignition instruction projections 22 are distributed according to the crankpin angle. Since this engine has three cylinders, it is arranged every 120 °.

In this ignition device, when the starting point setting projection 21 and each ignition instruction projection 22 pass near the ignition instruction detection sensor 20, a detection signal having a length proportional to the circumference is ignited from the ignition instruction detection sensor 20. It is transmitted to the control device 4. In the ignition control device 4, the detection signal indicates that the starting point setting protrusion 21
It is discriminated whether it is the starting point setting signal based on the above or the ignition instruction signal based on the ignition instruction protrusion 22 by the difference in the length. Further, the three kinds of ignition instruction signals based on the three kinds of starting point setting protrusions 21 are specified by the reception order starting from the reception of the starting point setting signal. Then, the corresponding three cylinders are ignited in order in the order of receiving the ignition instruction signal. This ignition is performed by either single ignition by the main ignition plug 2 or two-plug ignition by the main ignition plug 2 and the auxiliary ignition plug 3.

In order to adjust the ignition state according to the engine operating state, this ignition device has the following structure. A negative pressure sensor 5 for detecting an intake negative pressure is arranged downstream of the throttle valve 15 in the intake passage 12, and is linked to the ignition control device 4. Further, the ignition instruction detection sensor 2
0 is also used as the speed sensor 6 for detecting the engine rotation speed. The negative pressure detection sensor 6 sends an intake negative pressure signal corresponding to the intake negative pressure, and the speed sensor sends a speed signal corresponding to the rotation speed to the ignition control device 4.

The ignition control device 4 identifies the engine operating state based on the detection of these signals. That is,
When the engine speed is detected to be less than 800 rpm by the speed signal, it is identified that the engine operating condition is in the starting range. Further, when it is detected by the speed signal that the engine rotation speed is 800 rpm or more, the engine operating state is determined by the speed signal and the intake negative pressure signal in any of the partial load region, the full load region, and the overload region. Identify if there is. That is, in this engine, due to the action of the governor mechanism, at a constant rotation speed, as the load increases, the opening degree of the throttle valve increases and the intake negative pressure on the downstream side of the throttle valve 15 decreases. The engine operating state can be identified by detecting the intake negative pressure.

The case where the engine rotation speed is 1800 rpm will be described as a specific example. As shown in FIG. 2, the ignition control device 4 identifies the engine operating state based on the intake negative pressure as follows. That is, it is identified as a partial load region when the intake negative pressure exceeds 200 mmHg, a full load region when the intake negative pressure is near 200 mmHg, and an overload region when the intake negative pressure is below 200 mmHg. The value of the intake negative pressure is displayed as a gauge pressure with the atmospheric pressure set to 0.

The ignition control device 4 adjusts the ignition state as follows based on the detection of the engine operating state. Figure 1
As shown in (B), when the engine operating state is in the full load region, the two-plug ignition by the main spark plug 2 and the auxiliary spark plug 3 is performed in this full load region. When the engine operating condition is in the partial load region, the auxiliary ignition by the auxiliary spark plug 3 is stopped in this partial load region. In this case, the ignition state is the single ignition by the main spark plug 1. Also, when the engine operating condition is in the overload region,
Two-plug ignition is performed in this overload region, but the ignition timing difference is made smaller than the ignition timing difference in the full load region at the same engine speed. Further, when the engine operating state is in the starting region, the two-plug ignition is performed in this starting region, but the ignition timing difference is made smaller than the ignition timing difference in the full load region.

A case where the engine speed is 1800 rpm will be explained as a specific example. As shown in FIG. 1B, in the full load region, the ignition timing of the main ignition by the main ignition plug 2 is set to 15 ° before the top dead center. The ignition timing of the auxiliary ignition by the auxiliary ignition plug 2 is set to 15 ° after top dead center, that is, the ignition timing difference is set to 30 °. In the partial load region, the ignition timing of the main ignition by the main ignition plug 2 is set to 15 ° before the top dead center, and the auxiliary ignition by the auxiliary ignition plug 2 is not performed. Further, in the overload region, the ignition timing of the main ignition of the main ignition plug 2 is 15 ° before top dead center, and the ignition timing of the auxiliary ignition by the auxiliary ignition plug 2 gradually increases from 15 ° before top dead center as the load increases. Move closer to 0 ° of top dead center. Further, in the starting region, both the ignition timing of the main ignition by the ignition timing of the main ignition plug 2 and the ignition timing of the auxiliary ignition by the auxiliary ignition plug 3 are 15 ° before top dead center, that is, the ignition timing difference is zero. Simultaneous ignition. In addition, the frequency of the ignition timing is displayed by the crank angle.

The specific values of the above-mentioned intake negative pressure, ignition timing, and ignition timing difference are such that the engine speed is 1
This is only an example in the case of 800 rpm, and these specific numerical values fluctuate according to the fluctuation of the engine rotation speed.
These proper numerical values at a specific engine speed are selected in advance based on experiments, etc., stored in the ignition control device as map data, and the corresponding data is extracted based on the detection of the engine speed, and this data is stored. Based on the above, the engine operating state is identified and the ignition state is controlled.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an ignition device of a spark ignition type engine according to an embodiment of the present invention, FIG. 1 (A) is a schematic diagram of the engine, and FIG. 1 (B) is a case where an engine rotation speed is 1800 rpm. It is a graph which shows the relationship between an engine operating state and an ignition state.

FIG. 2 is a graph showing a relationship between an intake negative pressure and an engine operating state when the engine rotation speed is 1800 rpm.

FIG. 3 is a view corresponding to FIG. 1 (B) of a conventional technique.

[Explanation of symbols]

1 ... Combustion chamber, 2 ... Main spark plug, 3 ... Auxiliary spark plug,
4 ... Ignition control device, 5 ... Negative pressure sensor, 6 ... Speed sensor.

Claims (3)

[Claims] 1. A main spark plug (2) and an auxiliary spark plug (3) are provided in a combustion chamber (1), and both spark plugs (2) and (3) are linked to an ignition control device (4). In a spark ignition engine ignition device configured to perform two-plug ignition by both spark plugs (2) and (3) in a combustion chamber (1), a negative pressure sensor (5) for detecting intake negative pressure and A negative pressure sensor is provided with a speed sensor (6) for detecting the engine rotation speed.
(5) and the speed sensor (6) are linked to the ignition control device (4), and based on the detection of the intake negative pressure and the engine rotation speed,
The ignition control device (4) is capable of detecting an engine operating state, and the ignition control device (4) detects that the engine operating state is in a partial load region.
The spark ignition engine ignition device is characterized in that the auxiliary ignition by the auxiliary spark plug (3) in the partial load region is stopped. 2. A main ignition plug (2) and an auxiliary ignition plug (3) are provided in a combustion chamber (1), and both ignition plugs (2) and (3) are linked to an ignition control device (4), In a spark ignition engine ignition device configured to perform two-plug ignition by both spark plugs (2) and (3) in a combustion chamber (1), a negative pressure sensor (5) for detecting intake negative pressure and A negative pressure sensor is provided with a speed sensor (6) for detecting the engine rotation speed.
(5) and the speed sensor (6) are linked to the ignition control device (4), and based on the detection of the intake negative pressure and the engine rotation speed,
The ignition control device (4) is capable of detecting an engine operating state, and the ignition control device (4) detects that the engine operating state is in an overload region.
However, the ignition timing difference of the two-plug ignition in the overload region is set to be smaller than the ignition timing difference in the full load region at the same engine rotation speed. 3. A main ignition plug (2) and an auxiliary ignition plug (3) are provided in a combustion chamber (1), and both ignition plugs (2) and (3) are linked to an ignition control device (4). In a spark ignition engine ignition device configured to perform two-plug ignition by both spark plugs (2) and (3) in a combustion chamber (1), a negative pressure sensor (5) for detecting intake negative pressure and A negative pressure sensor is provided with a speed sensor (6) for detecting the engine rotation speed.
(5) and the speed sensor (6) are linked to the ignition control device (4), and based on the detection of the intake negative pressure and the engine rotation speed,
The ignition control device (4) enables detection of the engine operating state, and the ignition control device indicates that the engine operating state is in the starting region.
Based on the detection by (4), the ignition control device (4)
An ignition device for a spark ignition type engine, wherein an ignition timing difference between two plug ignitions in a starting region is made smaller than an ignition timing difference in a full load region at the same engine speed.