JP2792081B2 - Ignition timing control device for spark ignition type internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ignition timing control device for a spark ignition type internal combustion engine such as a gasoline engine (hereinafter, “internal combustion engine” may be simply referred to as “engine”). .

[Related Art] Conventionally, for example, ignition timing control of a gasoline engine has been performed as follows. That is, the flow rate sensor for detecting the intake air amount of the engine (a pressure sensor for detecting the intake passage pressure may be used instead of the flow rate sensor) and the engine speed sensor for detecting the engine speed determine the operating state of the engine. Based on detection results from these sensors, a volume efficiency Ev (A / N) obtained by dividing the intake air amount A by the engine speed N or an advance angle determined by the intake passage pressure and the engine speed N Basic ignition timing information is obtained from a two-dimensional map having values (ignition timing information), and the basic ignition timing information is appropriately corrected.
The ignition timing of the engine is controlled by operating an ignition device (ignition plug, ignition coil, etc.) based on the ignition timing information obtained in this manner.

[Problems to be Solved by the Invention] The appropriate correction to be performed on the basic ignition timing information described above includes a correction based on an engine cooling water temperature and a correction based on an intake air temperature. Since knocking (knocking) occurs, some correction must be made to the ignition timing information even when the engine is accelerating.

Incidentally, one of the causes of knocking during acceleration of the engine is that the vaporization characteristics of each fuel component are not uniform.

That is, gasoline usually comprises a plurality of components having different octane numbers, and these components usually have different vaporization characteristics. Also, in a fuel injection type gasoline engine, not all the injected fuel enters the combustion chamber at the same time,
Part of the gas adheres to the intake passage, and then gradually evaporates and is sucked into the combustion chamber. In this case, since the vaporization characteristics of each fuel component are not uniform, the octane number at the time of combustion in the combustion chamber does not always match that of the original fuel. Therefore, particularly when a large amount of fuel is injected, such as during rapid acceleration, the octane number is reduced, and knock is likely to occur.

Therefore, conventionally, in order to prevent the occurrence of knock, control is generally performed to delay the ignition timing, but in this case, it is impossible to detect a decrease in octane number at the time of combustion, which leads to the occurrence of knock. For this reason, a control method is adopted in which the ignition timing is delayed to a safe side so that knock does not occur even in the worst condition.

The present invention was devised under such a circumstance, and uses a required mathematical model to estimate an octane number during combustion in a combustion chamber in real time, and obtain ignition timing information based on the estimated octane number. Accordingly, it is an object of the present invention to provide an ignition timing control device for a spark ignition internal combustion engine, which is capable of realizing optimal ignition timing control for improving output and improving fuel efficiency.

Means for Solving the Problems In order to achieve the above object, an ignition timing control apparatus for a spark ignition type internal combustion engine according to the present invention provides an ignition timing for setting an ignition timing according to an operation state of the spark ignition type internal combustion engine. Setting means;
In an ignition timing control device for a spark ignition type internal combustion engine having an ignition device operating device for operating an ignition device based on ignition timing information set by the ignition timing setting device, the ignition timing setting device sends the ignition timing to the internal combustion engine. Supply fuel amount measuring means for measuring the amount of fuel supplied, vaporization characteristic / octane number setting means for specifying the composition of the fuel and setting the vaporization characteristic and octane number for each fuel component contained in the specified composition Octane number estimation for estimating the actual octane number of the fuel in the combustion chamber based on the supplied fuel amount measured by the supplied fuel amount measuring means and the octane number of each fuel component set by the vaporization characteristic / octane number setting means. Means, and ignition timing calculation means for obtaining the ignition timing based on the actual octane number estimated by the octane number estimation means. It is characterized in that there.

[Operation] In the ignition timing control device for a spark ignition type internal combustion engine of the present invention described above, the ignition device is operated based on the ignition timing information set by the ignition timing setting means. At this time, the ignition timing is as follows. Is required. That is, first, the composition of the fuel is specified by the vaporization characteristic / octane number setting means, and the vaporization characteristic and the octane number are set for each fuel component included in the specified composition. Next, the octane number estimating means, the supplied fuel amount obtained by the supplied fuel amount measuring means,
The actual octane number of the fuel in the combustion chamber is estimated based on the vaporization characteristic and the octane number for each fuel component set by the vaporization characteristic / octane number setting means. The ignition timing is determined based on the octane number.

[Embodiment] Hereinafter, an ignition timing control apparatus for a spark ignition type internal combustion engine as an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram showing a control system and an engine schematic system, FIG. FIG. 3 is a diagram for explaining the combustion octane number estimation model, and FIG. 3 is a flowchart for obtaining the ignition timing.

The vehicle-mounted gasoline engine system (spark ignition type internal combustion engine system) controlled by this device is the first type.
As shown in FIG. 1, in FIG. 1, a gasoline engine E (hereinafter simply referred to as engine E) has a combustion chamber 1 thereof.
The intake passage 2 and the exhaust passage 3 communicate with each other. The communication between the intake passage 2 and the combustion chamber 1 is controlled by an intake valve 4, and the communication between the exhaust passage 3 and the combustion chamber 1 is controlled by an exhaust valve 5. It has become so.

In addition, an air cleaner is provided in the intake passage 2 in order from the upstream side.
6, a throttle valve 7 and an electromagnetic combustion injection valve (injector) 8 are provided. In the exhaust passage 3, a catalytic converter (three-way catalyst) for purifying exhaust gas and a muffler (muffler) Device) is provided.

Note that the injectors 8 are provided in the intake manifold portion by the number of cylinders. Now, assuming that the engine E of this embodiment is an in-line four-cylinder engine, four injectors 8 are provided. That is, it can be said that the engine is a so-called multipoint fuel injection (MPI) type engine.

Further, the throttle valve 7 is connected to the accelerator pedal via a wire cable, so that the opening degree changes according to the amount of depression of the accelerator pedal.

Further, each cylinder is provided with an ignition plug 9 toward the fuel chamber 1, and each ignition plug 9 is connected to an ignition coil 10 via a distributor (not shown). And a power transistor with an ignition coil 10
A high voltage is generated in the ignition coil 9 by the OFF operation of the ignition coil 9 and the ignition plug 9 connected to the distributor
Is sparked (ignited).
The ignition coil 10 is started to be charged by the battery when the power transistor 11 is turned on. And these spark plug 9, distributor, ignition coil 1
0, The power transistor 11 constitutes an ignition device.

With such a configuration, the air sucked through the air cleaner 6 according to the opening degree of the throttle valve 7 is mixed with the fuel from the injector 8 at the intake manifold portion so as to have an appropriate air-fuel ratio. 9 is ignited at an appropriate timing to be burned to generate engine torque, and then the air-fuel mixture is discharged to the exhaust passage 3 as exhaust gas, and the catalytic converter converts CO, HC, and NO _{X in} the exhaust gas. After purifying the three harmful components,
The sound is muted by the muffler and released to the atmosphere.

Further, various sensors are provided to control the engine E. First, on the side of the intake passage 2, an air flow sensor (engine load sensor) 13 as a volume flow meter for detecting an intake air amount from Karman vortex information, an intake air temperature sensor for detecting an intake air temperature, and a large An atmospheric pressure sensor for detecting the atmospheric pressure is provided, and a potentiometer type throttle sensor for detecting the opening degree of the throttle valve 7 and an idle switch for detecting an idling state are provided in a portion where the throttle valve is provided.

Further, on the exhaust passage 3 side, the oxygen concentration (O ₂ concentration) in the exhaust gas is located in a portion near the combustion chamber 1 on the upstream side of the catalytic converter.
Is provided with an oxygen concentration sensor (O ₂ sensor) for detecting the pressure.

Further, in addition to a water temperature sensor for detecting an engine cooling water temperature, a crank angle sensor 14 for detecting a crank angle (the crank angle sensor 14 also serves as an engine speed sensor for detecting the engine speed N, If necessary, the crank angle sensor 14 may be referred to as an engine speed sensor) and a TDC sensor for detecting the top dead center of the first cylinder (reference cylinder) is provided in each distributor.

By the way, the detection signals from the above-mentioned sensors are input to an electronic control unit (ECU) 15.

In terms of hardware, the ECU 15 has a CPU, RAM (including backup RAM), ROM, and an appropriate input / output interface circuit, and each sensor directly or directly from each sensor through the input interface circuit. Is input to the CPU, an ignition timing control signal from the CPU is output to the power transistor 11 through the output interface circuit, and further, each spark plug 9 is sequentially sparked from the ignition coil 10 via the distributor. It has become.

A fuel injection control signal is output from the CPU to the injector 8 through an output interface circuit, whereby fuel is injected from the injector 8 for a time determined by the fuel injection control signal to obtain a desired air-fuel ratio. Is controlled so that

Now, focusing on the ignition timing control, the ECU 15 is shown by using a functional block for such ignition timing control, as shown in FIG. That is, the ignition timing control device includes a supplied fuel amount measuring unit 20, a vaporization characteristic / octane number setting unit 21, an octane number estimating unit 22, an ignition timing calculating unit 23, and an ignition signal generating unit 24.

Here, the supplied fuel amount measuring means 20 measures the amount of fuel supplied to the engine ventilation passage 2 through the injector 8, and is obtained, for example, based on the time width of the fuel injection pulse supplied to the injector 8 or by the air flow sensor 13. The fuel amount is measured based on the intake air amount.

The vaporization characteristic / octane number setting means 21 presets the component ratio, the vaporization characteristic, and the octane number for each component of the fuel. The ratio, the vaporization characteristic, and the octane number are set in the fuel tank. The measurement may be automatically performed immediately or in the inserted state. The detection of the composition of the fuel and the measurement of the octane number of each component can be performed by using a known sensor technology. In this embodiment, the specific configuration of the vaporization characteristic / octane number setting means 21 is omitted. .

The octane number estimating means 22 includes the supplied fuel amount obtained by the supplied fuel amount measuring means 20 and the vaporization characteristics / octane number setting means.
The actual octane number (equivalent octane number) of the fuel in the combustion chamber 1 is estimated based on the vaporization characteristics and the octane number for each fuel component obtained in 21. For this purpose, the octane number estimation means 22 Vaporization / suction estimation means 22A for estimating the vaporization suction amount for each component from the information on the vaporization characteristics and the octane number preset for each component of the supplied fuel amount and the fuel obtained by the amount measurement means 20,
An equivalent octane number calculating means 22B for calculating an equivalent octane number from the vaporization / inhalation amount estimated by the vaporization / inhalation estimation means 22A is provided.

The ignition timing calculating means 23 calculates the ignition timing based on the equivalent octane number estimated by the octane number estimating means 22. The ignition timing calculating means 23 further determines the operating state of the engine E (this operating state is determined by an engine load sensor ( Two-dimensional ignition timing data (advance angle data) for determining the ignition angle (ignition timing) according to the engine load information from the air flow sensor 13 and the engine speed information from the engine speed sensor 14) is stored. Ignition timing map 23-1 to 23-
n has a plurality (n) of equivalent octane numbers. In the example shown in FIG. 1, the map 23-1 is for the minimum equivalent octane number, and the map 23-1n is for the maximum equivalent octane number. The maps having numbers between 23-1 to 23-n are for the equivalent octane number between the minimum equivalent octane number and the maximum equivalent octane number, and the maps with smaller suffix numbers are for the equivalent octane number. It is.

The ignition signal generating means 24 outputs an ignition signal for operating the power transistor 11 based on the ignition timing information calculated from the ignition timing calculating means 23. An ignition device operating means for operating an ignition device such as the power transistor 11 based on ignition timing information obtained according to the operating state of the engine. Further, the supplied fuel measuring means 20, the vaporization characteristics / octane number setting means 21, the octane number estimating means 22, and the ignition timing calculating means 23 constitute an ignition timing setting means.

Next, a method for estimating the equivalent octane number will be described.

First, consider a single composition fuel. in this case,
As shown in FIG. 2, assuming that the injection amount at the time _i is u _i , it is considered that the fuel is directly sucked at the rate of b and the remaining fuel adheres to the intake passage 2, and only a of the fuel adhering x _i is vaporized. Probably inhaled.

Then, the following equation is established for the amount of intake yi into the combustion chamber 1 and the increase (x _{i + 1} −x _i ) in the amount of adhesion to the inner wall surface of the intake passage.

_{yi = ax i + bu i ......} (1) x i + 1 -x i = (1-b) when u _i -ax _i ...... (2) further _{organize, x i = (1-a} ) x i-1 + (1-b) u _i-1 (3)

 Next, the above logic is extended to fuels having a plurality of compositions.

The adhesion vector for each component is Inhalation volume vector for each component And the vaporization coefficient matrix for each component is AA (this
AA diagonal components a _11, a _22, ··, sequential vaporization coefficient _{a nn a 1, a 2,} ·
· A _n is a matrix whose many parts are 0), and the vector is the weight ratio of each component x the direct inhalation rate And the weight ratio matrix for each component is W (where W is a diagonal component w ₁₁ , w ₂₂ ,..., W _nn is a weight ratio coefficient w ₁ , w ₂ ,.
_n , and the other parts are 0)
For multi-component fuels, Holds.

here, Is a unit vector, and I is a unit matrix.

 Next, the estimation of the equivalent octane number will be described.

First, a vector in which the octane number of each component is α _j is And And for some fuels, (weight ratio x
Since the equivalent octane number is obtained from the sum of the octane numbers, the following equation can be approximately used.

Here, O _Ni is the equivalent octane number at time i, and t is the transposition of the vector.

In this manner, the equivalent octane number of the fuel having a plurality of compositions can be obtained.

When the error is large in the equation (6), a data table in which the octane number for each weight ratio is obtained in advance is used. in this case, Becomes

Next, the ignition timing calculation procedure will be described with reference to the flowchart of FIG.

First, in step a1, the vaporization characteristics of each component of the fuel
The octane number is read, and in step a2, the amount of injected fuel is measured, and in step a3, the above-described vaporization / inhalation model is calculated from the information to obtain the adhesion amount vector for each component. Inhalation volume for each component Ask for.

Next, in step a4, the equivalent octane number is calculated, and in step a5, the engine speed and load parameters are fetched. In step a6, the ignition angle is determined based on the equivalent octane number, engine speed, and engine load.

Then, as described above, when the ignition angle is determined (this ignition angle is settled for each ignition timing), an ignition signal is output from the ignition signal generating means 24 to the power transistor 11 based on this information. The ignition plug 9 is ignited at a timing corresponding to.

As described above, the equivalent octane number during combustion in the combustion chamber 1 can be estimated in real time using the required mathematical model, and the ignition timing information can be obtained based on the equivalent octane number. It is possible to realize optimal ignition timing control for improving output and improving fuel economy without delaying the ignition angle. In particular, since the optimal ignition angle at which no knock occurs during acceleration can always be set, knocking during acceleration can be reliably prevented while preventing rapid acceleration as much as possible. As a result, the engine output can be increased, the engine efficiency can be increased, and the acceleration performance can be significantly improved.

The ignition timing calculation means 23 is provided with an ignition timing map for the nominal octane number. If the estimated octane number does not significantly deviate from the nominal octane number, the ignition timing map for the nominal octane number is used to perform the estimation. The ignition timing correction may be performed only when the octane number thus set deviates greatly from the nominal octane number.

In controlling the ignition timing, a correction according to the water temperature or the intake air temperature may be added.

Further, the ignition timing calculation means 23 is constituted by basic ignition timing setting means, ignition timing correction amount setting means, and addition means for adding information obtained by these means, and the basic timing obtained according to the engine operating state is obtained. The ignition timing corrected by an ignition timing correction amount obtained according to the equivalent octane number may be used as the ignition timing information.

Further, the present invention can be applied to an engine that can use a plurality of fuels having different octane numbers, for example, an engine that can use a gazoline fuel or an alcohol blend fuel by using the same device.

Further, the present invention relates to a spark ignition type internal combustion engine employing an L jetro system using an air flow sensor, and a spark ignition type internal combustion engine employing a D jetro system (speed density system) using an intake passage pressure sensor. Is also applicable.

[Effects of the Invention] As described in detail above, according to the ignition timing control device of the spark ignition type internal combustion scoop of the present invention, the octane number during combustion in the combustion chamber is calculated in real time using a required mathematical model. Since the ignition timing information can be obtained based on the estimated octane number, it is possible to realize the optimum ignition timing control for the improvement of the output and the fuel consumption without unnecessarily delaying the ignition angle. Even if the octane number decreases, appropriate ignition timing information is taken out, whereby the optimal ignition angle at which knock does not occur can always be set. The advantage is that the engine output can be increased, the engine efficiency can be increased, and the acceleration performance can be greatly improved. There is.

[Brief description of the drawings]

1 to 3 show an ignition timing control device of a spark ignition type internal combustion engine as one embodiment of the present invention, FIG. 1 is an overall configuration diagram showing a control system and an engine schematic system, and FIG. A diagram for explaining the combustion octane number estimation model,
FIG. 3 is a flowchart for obtaining the ignition timing. 1 ... combustion chamber, 2 ... intake passage, 3 ... exhaust passage, 4 ...
... intake valve, 5 ... exhaust valve, 6 ... air cleaner, 7 ...
Throttle valve, 8 ... Solenoid valve (injector), 9 ...
Spark plug constituting ignition device, 10 Ignition coil, 11
… Power transistor, 13… Air flow sensor (volume flow meter) as engine load sensor, 14… Crank angle sensor (engine speed sensor), 15… ECU, 20
………………………………………………………………………………………………………………………… ······································
Inhalation estimation means, 22B ... equivalent octane number calculation means, 23
... Ignition timing calculation means, 23-1, 23-n ... Ignition timing map, 24 ... Ignition signal generation means, (Ignition device operation means),
E ... Engine.

Continuing on the front page (72) Inventor Jun Takemura 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Eiichi Shinji 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi (56) References JP-A-2-40057 (JP, A) JP-A-1-76567 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02P 5/15 F02D 45/00 368

Claims (1)

(57) [Claims] 1. An ignition timing setting means for setting an ignition timing according to an operation state of a spark ignition type internal combustion engine, and an ignition device operating means for operating an ignition device based on ignition timing information set by the ignition timing setting means An ignition timing control device for a spark ignition type internal combustion engine, comprising: a supply fuel amount measurement unit for measuring an amount of fuel supplied to the internal combustion engine; and A vaporization characteristic / octane number setting means for setting a vaporization characteristic and an octane number for each fuel component included in the specified composition; and a supply fuel amount measured by the supplied fuel amount measurement means and the vaporization characteristic / octane number setting means. Octane number estimating means for estimating the actual octane number of the fuel in the combustion chamber based on the set octane number for each fuel component; In characterized in that it is configured to include an ignition timing calculation means for calculating the ignition timing based on the estimated the actual octane number, the ignition timing control apparatus for a spark ignition internal combustion engine.