JP2007040264A - Engine ignition control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition control device adaptable to a change in ignition timing without causing the deterioration of an ignition coil. <P>SOLUTION: The ignition control device comprises the ignition coil 45 having a primary coil 45a to be connected to a battery via a switch and a secondary coil 45b to be connected to an ignition plug 41 for igniting the ignition plug 41 with the energization/deenergization of the primary coil 45a, ignition timing control means (Steps S40, S50, S110) for igniting the ignition plug 41 in a delayed ignition mode or in an advanced ignition mode depending on the operated condition of an engine, a catalyst activation determining means (Step S10) for determining whether an exhaust purifying catalyst 36 is in a partially activated condition or not, and coil energization control means (Steps S20, S30) for starting the energization of the primary coil 45a at a timing in the advanced ignition mode independently of the operated condition of the engine when the exhaust purifying catalyst 36 is in the partially activated condition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus for controlling ignition of an engine.

A catalyst for purifying exhaust gas is provided in the exhaust passage of the engine. This catalyst cannot exhibit exhaust purification performance unless it is at a temperature higher than the activation temperature. Therefore, conventionally, in order to activate the catalyst early, the ignition timing is delayed from the normal ignition timing (MBT (Minimum Spark Advance for Best Torque)) during warm-up of the catalyst. It was horny.
JP-A-6-146955

  However, since the exhaust gas purification performance of the catalyst is insufficient during such warming-up, unburned hydrocarbons (hereinafter referred to as “emissions”) are discharged from the engine even if it takes time until the catalyst is fully activated. Decreasing the amount of emission of “unburned HC”) may reduce the amount of unburned HC discharged to the atmosphere as a whole vehicle. According to the inventors, under predetermined operating conditions, the ignition timing of the spark plug is advanced from the ignition timing after warm-up, thereby reducing exhaust components such as unburned hydrocarbons discharged from the engine. It was confirmed that it was possible. Therefore, the inventors of the present invention have a mode in which the ignition timing is retarded from MBT (hereinafter referred to as “retarded ignition mode”) and a mode in which the ignition timing is advanced from MBT (hereinafter referred to as “advanced ignition mode”). ”), The unburned HC discharged into the atmosphere as a whole vehicle is reduced.

  However, when the ignition timing is changed from the advanced state to the retarded state, the ignition coil is charged too long, and there is a possibility of deterioration due to heat generation. On the other hand, when the ignition timing is changed from the retarded state to the advanced angle state, there is a possibility that the ignition coil cannot be charged in time.

  The present invention has been made paying attention to such conventional problems, and an object of the present invention is to provide an ignition control device that can cope with changes in ignition timing without causing deterioration of the ignition coil. Yes.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

  The present invention includes a primary coil (45a) connected to a battery (62) via a switch (61) and a secondary coil (45b) connected to a spark plug (41), and the primary coil (45a). The ignition coil (45) that ignites the ignition plug (41) by intermittently energizing the ignition plug and the ignition plug (41) according to the operating state of the engine are ignited at an ignition timing advanced from the ignition timing in normal operation. An ignition timing control means (steps S40, S50, S110) for igniting in an advanced ignition mode for performing ignition or a retarded ignition mode for igniting with an ignition timing delayed from that in normal operation, and an exhaust purification catalyst (36) When the catalyst activity determining means (step S10) for determining whether or not the engine is partially activated and the exhaust purification catalyst (36) are partially activated, the engine operating condition is related. Not, and having a coil energization control means for starting the energization of the the advanced ignition mode the primary coil at the timing of (45a) (step S20, S30).

  According to the present invention, the ignition plug is ignited in the retarded ignition mode or the advanced ignition mode according to the operating state of the engine, and when the exhaust purification catalyst is partially activated, regardless of the operating state of the engine, Since the primary coil is energized at the timing of the advance ignition mode, the ignition coil can be sufficiently charged even when the ignition timing is changed from the retarded state to the advanced state. is there.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

  FIG. 1 is a diagram showing an embodiment of an engine ignition control apparatus according to the present invention.

  The engine 1 is an in-cylinder direct injection type spark ignition engine. The engine 1 connects an intake passage 21 and an exhaust passage 31 to the combustion chamber 11 via an intake valve 22 and an exhaust valve 32. The intake cam 23 opens and closes the intake valve 22. The exhaust cam 33 opens and closes the exhaust valve 32.

  The exhaust purification catalyst 36 is a three-way catalyst that simultaneously purifies nitrogen oxides (NOx), hydrocarbons (HC), and carbon monoxide (CO) when the catalyst atmosphere is at the stoichiometric air-fuel ratio.

  The air-fuel ratio sensor 34 is provided upstream of the exhaust purification catalyst 36 and detects the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst 36.

  The fuel injection valve 42 is disposed in the vicinity of the approximate center of the combustion chamber 11 and offset and inclined toward the front side of the engine. The fuel injection valve 42 is a multi-hole injection valve. The spark plug 41 is disposed so as to be inclined toward the rear side of the engine opposite to the fuel injection valve 42. The spark plug 41 is connected to the ignition coil 45 and generates a high voltage.

  The piston 12 has a circular cavity formed in the crown surface when viewed from above.

  The controller 50 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 50 may be composed of a plurality of microcomputers. The controller 50 determines the fuel injection timing of the fuel injection valve 42 and the spark plug 41 based on the air flow meter signal, accelerator opening signal, crank angle sensor signal, water temperature sensor 13 signal, air-fuel ratio sensor 34 signal, and catalyst temperature sensor 35. Control the ignition timing. Specific control of the controller 50 will be described later.

  FIG. 2 is a view for explaining the ignition coil.

  As shown in FIG. 2A, the ignition coil 45 includes a primary coil 45a and a secondary coil 45b. The primary coil 45 a connects the battery 62 via the switch 61. The secondary coil 45b connects the spark plug 12.

As shown in FIG. 2 (B), for example, by closing the switch 61 current flows in the primary coil 45a at time t _21, when opening the switch 61 at time t _22, the electromotive force by the self-induction effect in the primary coil 45a At the same time, an electromotive force is induced in the secondary coil 45b by a mutual induction action, and a high voltage is generated.

  FIG. 3 is a diagram showing the spray and mixture behavior in the retarded ignition mode.

  In the retarded ignition mode, fuel is injected in the latter half of the compression stroke (for example, about 50 degBTDC) (FIG. 3A). Then, the injected fuel collides with the bottom surface of the cavity, is further guided to the side surface of the cavity (FIG. 3B), and circulates and flows in the combustion chamber (FIG. 3C). In such a state, even if the ignition timing is set after top dead center (for example, about 20 degATDC), stable combustion can be obtained. Further, by retarding the ignition timing, the combustion becomes slow, the exhaust temperature rises, and the emission of unburned hydrocarbons (unburned HC) is suppressed.

  In the advance ignition mode, fuel is injected in the intake stroke. Then, the injected fuel spreads in the combustion chamber while mixing with the air sucked from the intake port, and a homogeneous air-fuel mixture is generated in the combustion chamber in the latter half of the compression stroke. The ignition timing in this case is advanced from MBT (for example, about 40 degBTDC). This lengthens the combustion period in the combustion chamber and reduces unburned HC.

  FIG. 4 is a diagram showing the relationship between the engine load, the air-fuel ratio, and the exhausted unburned HC in the retarded ignition mode and the advanced ignition mode.

  As the load increases, the amount of fuel injection increases, and therefore the spark plug is excessively rich in the retarded ignition mode (compression stroke injection), and there is a concern that smoke may be generated. Therefore, it is necessary to make the air-fuel ratio lean (FIG. 4A). As a result, under a certain load, the amount of unburned HC discharged becomes smaller in the advance ignition mode (intake stroke injection) (FIG. 4B).

  Therefore, the retarded ignition mode (compression stroke injection) is set when the load is low, and the advanced ignition mode (intake stroke injection) is set when the load is high.

  Here, the points of the present invention will be described.

  According to the knowledge of the inventors, when the catalyst is partially activated, the vehicle as a whole is discharged to the atmosphere by properly using the retard ignition mode and the advance ignition mode according to the operating state of the engine. Unburned HC generated can be reduced. However, when the ignition timing is changed from the retarded state to the advanced state, the ignition coil may not be charged in time.

  Therefore, in the present invention, when the catalyst is partially active, charging is always performed by starting energization of the primary coil of the ignition coil at the timing of the advance ignition mode regardless of the retard ignition mode or the advance ignition mode. I tried to do that.

  However, if energization of the primary coil of the ignition coil is always started at the timing of the advance ignition mode as described above, the ignition coil may be charged too long and deterioration due to heat generation may occur. Therefore, in the case of the retard ignition mode, it is determined whether or not the primary coil charging time can be secured. If the primary coil charging time can be secured, the ignition coil is protected by flash firing once.

  Below, the concrete control logic of the controller 50 is demonstrated along the flowchart of FIG.

  In step S10, the controller 50 determines whether or not the catalyst 36 is in a partially activated state (a state in which it is activated in at least a part of the region). Specifically, for example, the determination may be made based on the catalyst temperature detected by the catalyst temperature sensor 35, or the catalyst state may be estimated based on the water temperature detected by the water temperature sensor 13. If it is partially activated, the process proceeds to step S20. If not partially activated, the process is exited.

  In step S20, the controller 50 determines whether or not the primary coil energization start timing of the advance ignition mode has passed. The ignition timing in the advance ignition mode is determined based on a characteristic map stored in the ROM in advance, and the primary coil energization start timing necessary for securing the charging time for ignition at the ignition timing is also determined in advance in the ROM. It is determined based on the characteristic map stored in If the primary coil energization start time has passed, the process proceeds to step S30, but if not, the process is exited.

  In step S30, the controller 50 closes the switch 61 and energizes the primary coil 45a.

  In step S40, the controller 50 determines whether or not the advance ignition mode is set. If it is the advance ignition mode, the process proceeds to step S50, and if it is the retard ignition mode, the process proceeds to step S60.

  In step S50, the controller 50 ignites at the ignition timing in the advance ignition mode.

  In step S60, the controller 50 calculates the ignition timing in the retarded ignition mode. The ignition timing in this retarded ignition mode is also determined based on a characteristic map stored in advance in the ROM.

  In step S70, the controller 50 determines whether or not the primary coil energization start timing has passed in the retarded ignition mode. That is, the primary coil energization start timing necessary for securing the charging time for ignition at the ignition timing in the retarded ignition mode is determined based on the characteristic map stored in advance in the ROM. If the primary coil energization start time has not passed, the process proceeds to step S80, and if it has passed, the process proceeds to step S110.

  In step S80, the controller 50 determines whether or not fuel has been injected. If it is before injection, the process proceeds to step S90, and if after injection, the process proceeds to step S110.

  In step S90, the controller 50 ignites with a spark plug (colored ignition). That is, since no fuel is injected into the combustion chamber, no explosion occurs even when the ignition plug is ignited.

  In step S100, the controller 50 resumes energization from the primary coil energization start timing in the retarded ignition mode.

  In step S110, the controller 50 ignites at the ignition timing in the retarded ignition mode.

  FIG. 6 is a time chart when this control is performed. In order to make the correspondence with the flowchart of FIG. 5 easier to understand, the step numbers of FIG.

  In the advance ignition mode, as shown in FIG.

When the primary coil energization start timing in the advance ignition mode has passed at time t ₀ , the primary coil is energized, and ignition is performed at the ignition timing in the advance ignition mode at time t _A1 (S10 → S20 → S30 → S40 → S50).

  In the retarded ignition mode, there are a case where there is no color firing and a case where there is a color firing. First, with reference to FIG. 6 (B), a case where no color strike is performed will be described.

When the primary coil energization start timing in the advance ignition mode has passed at time t ₀ , the primary coil is energized (S10 → S20 → S30). Since the fuel has already been injected at the time t _{B1 at which} the stroke is determined, ignition is performed at time t _B2 , which is the normal ignition timing in the retarded ignition mode (S60 → S70 → S80 → S110).

  Next, with reference to FIG. 6 (C), a case where the spark firing is performed will be described.

When the primary coil energization start timing in the advance ignition mode has passed at time t ₀ , the primary coil is energized (S10 → S20 → S30). Since the fuel is not yet injected at the time of tapping judgment at time t _C1, the tapping ignition is performed (S60 → S70 → S80 → S90). Then, energization of the primary coil is resumed from time t _C2 which is the primary coil energization start timing in the retarded ignition mode, and ignition is performed at time t _C3 which is the normal ignition timing in the retarded ignition mode (S100 → S110).

  According to the present embodiment, when the catalyst is partially active, the primary coil of the ignition coil is always energized and charged in the advance ignition mode regardless of the retard ignition mode and the advance ignition mode. I did it. Since it did in this way, even if it is a case where ignition timing is changed from a retarded state to an advanced state, an ignition coil can fully be charged.

  Further, when the ignition mode is retarded and the primary coil charging time can be secured, the flash firing is temporarily performed. By doing in this way, the durability performance of an ignition coil increases.

  The present invention is not limited to the embodiment described above, and various modifications and changes can be made within the scope of the technical idea, and it is obvious that these are equivalent to the present invention.

  For example, as shown in FIG. 7, an engine that directly ignites the fuel injected from the fuel injection valve 42 with a spark plug 41 without passing through a piston cavity may be used.

It is a figure which shows one Embodiment of the ignition control apparatus of the engine by this invention. It is a figure explaining an ignition coil. It is a figure which shows the spraying and air-fuel | gaseous mixture behavior in retard ignition mode. It is a figure which shows the relationship between the engine load in a retarded ignition mode and an advanced ignition mode, an air fuel ratio, and discharge | emission unburned HC. It is a flowchart shown about the specific control logic of a controller. It is a time chart when this control is implemented. It is a figure which shows the engine which ignites directly the fuel injected from the fuel injection valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 11 Combustion chamber 36 Exhaust purification catalyst 41 Spark plug 42 Fuel injection valve 45 Ignition coil 45a Primary coil 45b Secondary coil 50 Controller 61 Switch 62 Battery Step S10 Catalyst activity determination means Steps S20, S30, S100 Coil energization control means Step S40 , S50, S110 Ignition timing control means Steps S70, S80 Kara firing ignition determination means Step S90 Kara firing ignition means

Claims (9)

An ignition coil comprising a primary coil connected to the battery via a switch and a secondary coil connected to the spark plug, and igniting the spark plug by intermittently energizing the primary coil;
Depending on the operating condition of the engine, the ignition plug is ignited at an ignition timing that is ignited at an ignition timing that is advanced from the ignition timing at the normal operation, or a retard that ignites at an ignition timing that is retarded from the ignition timing at the normal operation. Ignition timing control means for igniting in ignition mode;
Catalyst activity determination means for determining whether or not the exhaust purification catalyst is partially active;
Coil energization control means for starting energization of the primary coil at the timing of the advance ignition mode regardless of the operating state of the engine when the exhaust purification catalyst is partially active;
An ignition control device for an engine. A color-hit ignition determination means for determining whether or not the spark plug can be light-fired based on the operating state of the engine in the retard ignition mode;
When it is determined that it is possible to perform flash firing, the blow ignition means for firing the spark plug by firing,
Have
The coil energization control means resumes energization to the primary coil after igniting the ball,
The ignition timing control means ignites a spark plug in the retard ignition mode;
The engine ignition control device according to claim 1. When in the retarded ignition mode, there is a color-igniting determination unit that determines whether the ignition plug can be color-ignited based on the operating state of the engine,
The coil energization control means maintains the energization state to the primary coil when the impact firing cannot be performed.
The engine ignition control device according to claim 1. The idle firing determination means determines that the idle firing cannot be performed when the primary coil energization start timing has passed in the retard ignition mode.
The engine ignition control device according to claim 2 or 3, wherein the engine ignition control device is provided. The idle firing determination means determines that the idle firing cannot be performed after the fuel is injected,
The engine ignition control device according to claim 2 or 3, wherein the engine ignition control device is provided. A fuel injection valve that injects fuel directly into the combustion chamber;
A piston which receives a fuel injected from the fuel injection valve and has a cavity on the crown surface capable of forming a stratified mixture near the fuel injection valve;
Have
The fuel injection valve injects fuel in a compression stroke in the retard ignition mode;
The engine ignition control device according to any one of claims 1 to 5, wherein the engine ignition control device is provided. The fuel injection valve injects fuel in an intake stroke in the advance ignition mode;
The engine ignition control device according to claim 6. A fuel injection valve that is disposed substantially at the center of the combustion chamber roof surface and directly injects fuel into the combustion chamber;
A spark plug disposed in the vicinity of the fuel injection valve;
The engine ignition control device according to any one of claims 1 to 5, wherein the engine ignition control device is provided. The igniter plug ignites the fuel injected from the fuel injection valve directly without passing through a piston cavity during stratification operation after the entire catalyst is activated.
The engine ignition control device according to claim 8, comprising:

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