JP2000018141A - Ignition energy control device using in-cylinder pressure sensor - Google Patents

Abstract

(57) [Problem] To provide an ignition energy control device using an in-cylinder pressure sensor capable of optimally setting the energization time of an ignition coil in accordance with the load condition of an engine determined according to the in-cylinder pressure. provide. SOLUTION: In an ignition control device including an engine 1 spark-ignited by an ignition coil 13 and an in-cylinder pressure sensor 17 for detecting an in-cylinder pressure Pcyl of the engine 1, in accordance with an output signal of the in-cylinder pressure sensor 17. , The ignition coil 1
3 is provided with an energization time determining means (steps 1 and 2) for determining an energization time Ton for the power supply 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition energy control device using an in-cylinder pressure sensor, and more particularly, to a device for determining a current supply time to an ignition coil in accordance with an in-cylinder pressure.

[0002]

2. Description of the Related Art In an internal combustion engine, the ignition timing is set at an optimum position slightly before the top dead center of the compression stroke in accordance with the engine load and the engine speed. Here, the ignition is performed by the back electromotive force when a current flows through the primary coil and the ignition energy stored in the secondary coil is cut off. Therefore, the problem is how much ignition energy is stored in the ignition coil, that is, how long the energizing time for the ignition coil is set. Generally, the time for energizing the ignition coil is set to be substantially constant in order to secure ignition energy.
On the other hand, when the ignition timing is set to an optimum position (crank angle position) in accordance with the engine load and the engine speed, the energization start timing for the ignition coil is determined based on the crank angle. For example, Japanese Patent Application Laid-Open No. 6-129333 discloses a technique in which the crank angle position is advanced as the engine speed increases in accordance with the engine speed.

[0003]

However, in the above-mentioned prior art, the energization start timing is set from the energization time to the crank angle position according to the engine speed on the basis of the case where the engine speed is stable. Therefore, for example, at the time of starting or the like in which the displacement of the crank angle per unit time is small, the time from the start of energization to the cutoff is longer than that in the case where the displacement of the crank angle per unit time is large. In addition, there is a problem in that the ignition energy becomes excessive, the electrode of the ignition plug is consumed greatly, the durability is reduced, and the fuel consumption is deteriorated.

On the other hand, if the energizing time is set on the basis of starting or the like, the energizing time is shortened when the engine speed is high, and the flame is extinguished even if the ignition is performed.
There is a problem that unburned gas is emitted, leading to air pollution. On the other hand, it is known that air in a cylinder acts as an insulator as a factor inhibiting ignition in a combustion chamber. Therefore, the present invention provides an ignition energy control device using an in-cylinder pressure sensor that can optimally set the energization time of an ignition coil in accordance with a load condition of an internal combustion engine obtained according to an in-cylinder pressure. Things.

[0005]

In order to solve the above-mentioned problems, in the present invention, an internal combustion engine (the engine 1 in the embodiment) which is spark-ignited by an ignition coil (the ignition coil 13 in the embodiment), and the internal combustion engine is provided. In an ignition control device provided with an in-cylinder pressure sensor (in-cylinder pressure sensor 17 in an embodiment) for detecting an in-cylinder pressure of an engine (in-cylinder pressure Pcyl in the embodiment), the ignition is performed in accordance with an output signal of the in-cylinder pressure sensor. An energization time determining means (steps 1 and 2 in the embodiment) for determining an energization time (Ton in the embodiment) to the coil is provided.

With this configuration, when the in-cylinder pressure is detected by the in-cylinder pressure sensor, the energization time of the ignition coil is determined by the energization time determination means in accordance with the output signal of the detected pressure. Since the energization time corresponds to the pressure in the cylinder, that is, the load condition of the internal combustion engine according to the pressure in the cylinder, the optimum ignition energy at that time is given. In other words, when the cylinder pressure increases, the amount of air in the cylinder increases, so that the air serving as an insulator becomes an obstacle to ignition. Therefore, the higher the cylinder pressure, the more ignition energy is required. Therefore,
It is effective to control the ignition energy, that is, the energization time to the ignition coil, by the cylinder pressure.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 1A showing an embodiment of the present invention, air is sucked into an engine (internal combustion engine) 1 from an air cleaner 2 through an intake duct 3, a throttle valve 4 and an intake manifold 5. A fuel injection valve 6 is provided at a branch of the intake manifold 5 for each cylinder. The fuel injection valve 6 is an electromagnetic fuel injection valve that is energized to open, is energized, is stopped when energized, and is energized by a drive pulse signal output from the control unit 7. Is intermittently injected and supplied with pressure-adjusted fuel at a predetermined pressure by a pressure regulator.

An ignition plug 8 is provided in each combustion chamber of the engine 1, and the mixture is ignited and burned by spark ignition by the ignition plug 8. Then, exhaust gas is discharged from the engine 1 through an exhaust manifold 9, an exhaust duct 10, a three-way catalyst 11, and a muffler 12. Here, as shown in FIGS. 2 and 3, the high voltage V generated by the ignition coil 13 (conducted for a predetermined time t with the current I) is sequentially distributed to the ignition plug 8 through the distributor 14. Thus, the ignition indicated by IG in FIG. 3 is executed for each cylinder.

That is, the distributor 14 is attached to a camshaft connected to the crankshaft of the engine 1 via a timing belt, and the camshaft rotates once every two rotations of the crankshaft, thereby causing the ignition coil 13 to rotate. The generated high voltage is sequentially distributed to the ignition plugs 8 of the respective cylinders. The control unit 7 is a CPU, ROM, RAM, A / D
A well-known microcomputer including a converter and an input / output interface receives input signals from various sensors, controls the fuel injection amount by the fuel injection valve 6 based on the input signals, 8 controls the ignition timing. As the various sensors, an air flow meter 15 is provided in the intake duct 3 and outputs a signal corresponding to the amount of intake air of the engine 1.

Further, a crank angle sensor 16 is provided on the crankshaft or camshaft. In a four-cylinder engine, a crank angle signal REF for each compression TDC of each cylinder and, for example, a compression TDC position for each cylinder of the # 1 cylinder are provided. And a cylinder discrimination signal. The engine speed Ne is calculated by measuring the cycle of the crank angle signal REF. Each ignition plug 8 is provided with an in-cylinder pressure sensor 17 as shown in FIG. The in-cylinder pressure sensor 17 is formed as a washer for the ignition plug 8 and detects the in-cylinder pressure Pcyl of each cylinder as a relative pressure by means of a piezoelectric element, as disclosed in Japanese Utility Model Application Laid-Open No. Sho 62-146941. . The in-cylinder pressure sensor 17 is of a type formed as a washer for the ignition plug 8 as described above, and also has a pressure sensor directly provided in the combustion chamber as disclosed in Japanese Patent Application Laid-Open No. 4-81557. There may be.

The throttle valve 4 is provided with a throttle sensor 18 for detecting the opening of the throttle valve 4. Here, the control for determining the energizing time to the ignition coil 13 by the control unit 7 is performed according to the flowchart shown in FIG. 4, and the ignition control is performed according to the flowchart shown in FIG.

First, in the flowchart of FIG. 4, the in-cylinder pressure sensor 17 detects the in-cylinder pressure Pcyl two cylinders ahead.
Are sampled (step 1). Here, at the time of the start where there is no data of two cylinders before, the cylinder pressure Pcyl at the time of the previous start stored in the RAM or the like in advance can be read. And, this cylinder pressure Pc
yl, an average effective pressure Pmi is obtained. Based on the average effective pressure Pmi, the control unit 7
Is provided by software, that is, as shown in FIG. 6, a map in which the energization time Ton of the ignition coil (primary-side coil) 13 that increases as the average effective pressure Pmi increases is stored. The table is searched (step 2). By using this map to determine the energization time Ton corresponding to the average effective pressure Pmi that accurately represents the load condition of the engine 1, optimal spark ignition is realized.
Here, in determining the energization time Ton, this is performed including correction by the battery voltage Vb. For example, when the battery voltage Vb is low, the energization time Ton is lengthened to reduce the ignition energy due to the decrease in the battery voltage Vb. Make up for it. Then, the obtained energization time Ton is stored in the RAM.

On the other hand, in the ignition control flowchart shown in FIG. 5, the ignition timing θi given as an advance value by the negative pressure Pb in the intake manifold 5 and the engine speed Ne.
g (see FIG. 3) is determined (step 10). Next, the energizing time Ton to the ignition coil 13 obtained in the flowchart in FIG. 4 is read from the RAM, and the energizing time Ton and the ignition timing θig of the previous step 10 are read.
And the engine speed Ne, the energization start timing θon (see FIG. 3) given as an advance value is determined (step 11). A known ignition energization cutoff (for example, described in JP-A-6-129333) is performed by the energization start time θon, the energization time Ton, and the ignition timing θig (step 12). That is, the ignition is performed in the optimal energizing time according to Pcyl.

Therefore, according to this embodiment, the cylinder pressure Pcy is obtained by the map showing the relationship between the average effective pressure Pmi based on the cylinder pressure Pcyl and the energization time Ton.
Optimal energization time To corresponding to the engine load that appears as l
Since n can be given, there is no problem such as extinction of flame as when the energizing time is too short, or exhaustion of the electrode of the spark plug 8 as when the energizing time is too long. Spark plug 8 that prevents contamination
Can extend the life and contribute to improving fuel efficiency. The embodiment of the present invention is not limited to the above-described embodiment. For example, the above-described control is performed only when the cooling water temperature has not risen and is not stable, and the engine is cooled by constant speed running or the like. When the water temperature becomes constant, normal ignition control can also be performed by reading a fixed energization time Ton in advance. Further, the case where the energization time Ton is obtained by the above-described map has been described, but this may be obtained by calculation.

[0015]

As described above, according to the present invention, when the in-cylinder pressure is detected by the in-cylinder pressure sensor,
According to the output signal of the detected pressure, the optimal energizing time of the ignition coil is determined by the energizing time determining means.
This eliminates problems such as extinguishment that occurs when the power-on time is too short, or exhaustion of the spark plug electrode when the power-on time is too long, thus preventing air pollution and extending the life of the spark plug. There is an effect that it can contribute to improvement of fuel economy as well as extension.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention;
(A) is an overall schematic explanatory view, and (b) is an enlarged view of a part X in (a).

FIG. 2 is a circuit diagram of an ignition device.

FIG. 3 is a graph showing the state of energization of an ignition coil.

FIG. 4 is a flowchart for determining an energization time.

FIG. 5 is a flowchart illustrating ignition control.

FIG. 6 is a graph showing average effective pressure and energization time of a cylinder.

[Description of Signs] 1 Engine (internal combustion engine) 13 Ignition coil 17 In-cylinder pressure sensor Pcyl In-cylinder pressure Pmi Average effective pressure Ton Energizing time Steps 1, 2 Energizing time determining means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazunori Sawamura 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Kenji Nakano 1-4-chuo Chuo, Wako-shi, Saitama No. 1 In Honda R & D Co., Ltd. (72) Inventor Hiroaki Kato 1-4-1 Chuo, Wako-shi, Saitama Prefecture Incorporated Honda R & D Co., Ltd. (72) Inventor Shunichi Tsuzuki 1-4-chuo, Wako-shi, Saitama No. 1 Inside Honda R & D Co., Ltd. (72) Inventor Kenji Abe 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside Honda R & D Co., Ltd. (72) Hideyuki Oki 1-4-4 Chuo, Wako-shi, Saitama Pref. No. 1 F-term in Honda R & D Co., Ltd. (reference) 3G019 CA00 DC01 DC06 EA16 GA01 GA05 GA07 GA08 GA09 GA15 KA28 3G084 BA16 DA02 DA10 EB11 FA03 FA07 FA10 FA21 FA33 FA38

Claims (1)

[Claims] 1. An ignition control device comprising: an internal combustion engine that is spark-ignited by an ignition coil; and an in-cylinder pressure sensor that detects an in-cylinder pressure of the internal combustion engine, wherein the ignition is performed in accordance with an output signal of the in-cylinder pressure sensor. An ignition energy control device using an in-cylinder pressure sensor, comprising an energization time determining means for determining an energization time to a coil.