JPH02223676A - Ignition timing control device for spark ignition type internal combustion engine - Google Patents

Abstract

PURPOSE:To enable improvement of an output by a method wherein based on information on a feed fuel amount, and gasifying characteristics and an octane number preset classified by a component, the octane number of fuel in a combustion chamber is estimated, and an ignition timing is determined according to the estimated octane number. CONSTITUTION:An octane number estimating means 22 of an ECU 15 has an estimating means 22A estimating a gasifying and suction amount and a calculating means 22B calculating an equivalent octane number of fuel in a combustion chamber 1, based on information on a feed fuel amount obtained by a measuring means 20, a component ratio, gasifying characteristics, and an octane number preset classified by a fuel component by means of a setting means 21. An ignition timing calculating means 23 selects either of a plurality of ignition timing maps 231 - 23n based on the estimated equivalent octane number, an ignition timing is determined through map retrieve of an ignition timing responding to signals from a load sensor 13 and a number of revolutions of engine sensor 14 to output it to an ignition signal generating means 24. This constitution enables reliable prevention of the occurrence of knock as acceleration performance is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is applicable to spark ignition internal combustion engines (such as gasoline engines).
The present invention relates to an ignition timing control device for an "internal combustion engine" (hereinafter sometimes referred to simply as an "engine").

[Prior Art] Conventionally, for example, ignition timing control of a gasoline engine has been performed as follows. In other words, the operating state of the engine is determined from a flow rate sensor that detects the intake air amount of the engine (a pressure sensor that detects the intake passage pressure may be used instead of this flow rate sensor) and an engine rotation speed sensor that detects the engine rotation speed. Based on the detection results of these sensors, the volumetric efficiency Ev (A/N) obtained by dividing the intake air amount A by the engine speed N, or the advance angle determined by the intake passage pressure and the engine speed N. Basic ignition timing information is obtained from a two-dimensional map with values (ignition timing information), appropriate corrections are made to this basic ignition timing information, and the ignition system (spark plug and The engine's ignition timing is controlled by operating the ignition coil (ignition coil, etc.).

[Problems to be Solved by the Invention] Appropriate corrections made to the above-mentioned basic ignition timing information include corrections based on the engine cooling water temperature and corrections based on the intake air temperature. Because knocking occurs.

It is necessary to make some kind of correction to the ignition timing information even when the engine is accelerating.

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

That is, gasoline typically consists of multiple components with different octane numbers, and the vaporization characteristics of these components typically differ. In addition, in a fuel-injected gasoline engine, not all of the injected fuel enters the combustion chamber at the same time; a portion of the fuel adheres to the intake passage, vaporizes at each plug, and is sucked into the combustion chamber.

In this case, since the vaporization characteristics of each fuel component are not uniform, the octane number during combustion within the combustion chamber does not always match that of the original fuel.

Therefore, especially when a large amount of fuel is injected during sudden acceleration, the octane number decreases, making knocking more likely.

Therefore, conventionally, control has been generally performed to delay the ignition timing in order to prevent the occurrence of such knock, but in this case, it is impossible to detect the decrease in octane number during combustion that leads to the occurrence of knock. Therefore, a control method is used to delay the ignition timing to a safe side that prevents knocking even under the worst conditions.

The present invention was devised under these circumstances, and involves estimating the octane number during combustion in the combustion chamber in real time using a required mathematical model, and obtaining ignition timing information based on this estimated octane number. An object of the present invention is to provide an ignition timing control device for a spark ignition internal combustion engine that can achieve optimal ignition timing control for improving output and improving fuel efficiency.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the ignition timing control device for a spark-ignition internal combustion engine of the present invention provides an ignition timing control device that sets the ignition timing according to the operating state of the spark-ignition internal combustion engine. A supply system comprising a setting means and an ignition device operating means for operating an ignition device based on ignition timing information set by the ignition timing setting means, the ignition timing setting means measuring an amount of fuel to be supplied to the internal combustion engine. The octane number of the fuel in the combustion chamber is determined based on a fuel amount measuring means, the amount of supplied fuel obtained by the supplied fuel amount measuring means, and information regarding the vaporization characteristics and octane number preset for each component of the fuel. The present invention is characterized in that it includes an octane number estimating means for estimating the octane number, and an ignition timing calculating means for calculating the ignition timing based on the octane number estimated by the octane number estimating means.

[Function] In the above-described ignition timing control device for a spark ignition internal combustion engine of the present invention, the ignition device is operated based on the ignition timing information set by the ignition timing setting means, but at this time, the ignition timing is determined as follows. required. That is, first, the octane number estimating means uses the amount of supplied fuel obtained by the supplied fuel amount measuring means, as well as information about the vaporization characteristics and octane number preset for each component of the fuel.

The octane number of the fuel in the combustion chamber is estimated, and then the ignition timing calculation means calculates one ignition timing based on the octane number estimated by the octane number estimation means.

[Embodiment] Hereinafter, an ignition timing control device for a spark ignition internal combustion engine as an embodiment of the present invention will be explained with reference to the drawings.
Figure 2 is an overall configuration diagram showing the control system and engine schematic system, Figure 2 is a diagram explaining the combustion octane number estimation model, and Figure 3 is a flowchart for determining the ignition timing.

Now, the in-vehicle gasoline engine system (spark ignition internal combustion engine system) controlled by this device is as shown in Fig. 1. In this Fig. 1, gasoline engine E (hereinafter simply referred to as engine E) is It has an intake passage 2 and an exhaust passage 3 that communicate with the combustion chamber 1, and the intake passage 2 and the combustion chamber 1 are controlled to communicate with each other by an intake valve 4, and the exhaust passage 3 and the combustion chamber 1 are connected with each other by an exhaust valve 5. Communication is controlled by.

In addition, an air cleaner 6 is installed in the intake passage 2 in order from the upstream side.
, a throttle valve 7 and an electromagnetic fuel injection valve (injector) 8 are provided in the exhaust passage 3, and a catalytic converter (not shown) for exhaust gas purification is installed in the exhaust passage 3 in order from the upstream side.
A three-way catalyst) and a muffler (silencer) are provided.

Note that the injectors 8 are provided in the intake manifold portion for the same number of cylinders. Now, the engine E in this example is an inline 4
Assuming that the engine is a cylinder engine, four injectors 8 are provided.

That is, it can be said to be a so-called multi-point 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 depending on the amount of depression of the accelerator pedal.

Further, each cylinder is provided with a spark plug 9 facing toward the combustion chamber 1 thereof, and each spark plug 9 is connected to an ignition coil 10 via a distributor (not shown). When the power transistor 11 with the ignition coil 10 is turned off, a high voltage is generated in the ignition coil 9, causing one of the ignition plugs 9 connected to the distributor to spark (ignite). By turning on the power transistor 11, the ignition coil 1o starts being charged by the battery. And these spark plugs9. Distributor, ignition coil 10. The power transistor 11 constitutes one ignition device.

With this configuration, the air taken in through the air cleaner 6 according to the opening degree of the throttle valve 7 is mixed with the fuel from the injector 8 in the intake manifold part so as to have an appropriate air-fuel ratio, and the spark plug is mixed in the combustion chamber 1. By igniting 9 at the appropriate timing, it is combusted,
After generating engine torque, the air-fuel mixture is discharged to the exhaust road 3 as exhaust gas, and the three harmful components of CO, HC, and NOx in the exhaust gas are purified by the catalytic converter, and then the noise is muffled by the muffler and released into the atmosphere. It is designed to be emitted to the side.

Furthermore, in order to control this engine E, various sensors are provided. First, on the intake passage 2 side, there is an air flow sensor (engine load sensor) 13° as a volume flow meter that detects the amount of intake air from Karman vortex information, an intake air temperature sensor that detects the intake air temperature, and a large An atmospheric pressure sensor for detecting 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 the idling state are provided in the throttle valve disposed portion of the atmospheric pressure sensor.

In addition, on the exhaust passage 3 side, the oxygen concentration (O2 concentration) in the exhaust gas is measured at the upstream side of the catalytic converter and close to the combustion chamber 1.
An oxygen concentration sensor (08 sensor) is provided to detect.

Furthermore, in addition to a water temperature sensor that detects the engine cooling water temperature, a crank angle sensor 14 that detects the crank angle (this crank angle sensor 14 is connected to the engine rotation speed N) is provided.
Since the crank angle sensor 14 also serves as an engine rotation speed sensor that detects the engine rotation speed sensor, the crank angle sensor 14 may be referred to as the engine rotation speed sensor hereinafter as needed) and the top dead center of the first cylinder (reference cylinder). A TDC sensor is provided at each distributor.

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

In addition, when looking at the configuration from a bird-aware perspective, the ECU 15 has a CPU, RAM (including backup RAM)
, ROM, and appropriate input/output interface circuits. Signals from each sensor are input to the CPU through the input interface circuit or directly, and ignition timing control signals from the CPU are input to the power source through the output interface circuit. The signal is outputted to the transistor 11, and further, the spark plugs 9 are sequentially distributed from the ignition coil 10 via the distributor.

Note that the CPU outputs an injection fuel control signal to the injector 8 through the output interface circuit, so that fuel is injected from the injector 8 for a time determined by this injection fuel control signal, and the desired air-fuel ratio is achieved. 2 Now, focusing on ignition timing control, the ECU 15 is shown using functional blocks for such ignition timing control.
The result will be as shown in the figure. That is, this ignition timing control device includes a supply fuel amount measuring means 20, a vaporization characteristic/octane number setting means 21. It has an octane number estimating means 221, an ignition timing calculating means 232, and an ignition signal generating means 24.

Here, the supplied fuel amount measuring means 20 measures the amount of fuel supplied through the engine intake passage 2 and 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 amount of fuel is measured based on the amount of intake air.

The vaporization characteristic/octane number setting means 21 is for presetting the component ratio, vaporization characteristic, and octane number for each component of the fuel. The measurement may be performed automatically when the device is in use or when it is inserted.

The octane number estimating means 22 calculates the amount of fuel in the combustion chamber 1 based on the supplied fuel amount obtained by the supplied fuel amount measuring means 20, the component ratio set in advance for each fuel component, the vaporization characteristics, and the octane number information. For this purpose, the octane number estimating means 22 estimates the octane number (equivalent octane number) of vaporization/inhalation estimating means 22A for estimating the vaporization/inhalation amount of each component from information about the vaporization/inhalation amount; and equivalent octane number calculation means for calculating an equivalent octane number from the vaporization/inhalation amount estimated by the vaporization/inhalation estimation means 22A. 22B.

The ignition timing calculating means 23 calculates the ignition timing based on the equivalent octane number estimated by the octane number estimating means 22, and furthermore, this ignition timing calculating means 23 calculates the ignition timing based on the operating state of the engine E (this operating state is determined by the engine load sensor). Two-dimensional ignition timing data (advanced angle data) in which the ignition angle (ignition timing) is determined according to the engine load information from the airflow sensor 13 and the L engine rotational speed information from the engine rotational speed sensor 14. Ignition timing map to be memorized 23
It has a plurality (n) of isometric octane deviations ranging from -1 to 23-n. In the example shown in FIG. 1, map 23-1 is for the minimum equivalent octane rating, and map 23-n
is for the maximum equivalent octane number. In addition,
Maps with numbers between 23-1 and 23-1 are for equivalent octane numbers intermediate between the minimum equivalent octane number and the maximum equivalent octane number, and the lower the suffix number, the lower the equivalent octane number. be.

Further, the ignition signal generation means 24 includes an ignition timing calculation means 23
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 information calculated from the ignition timing information calculated based on the engine operating state. An ignition device actuation means for actuating an ignition device such as the power transistor 11 based on the power transistor 11 is formed.

Next, methods for estimating the equivalent octane rating will be explained.

First, consider a fuel with a single composition. In this case, as shown in Fig. 2, if the injection amount at one time is ul, it is thought that b of the amount is directly inhaled and the rest is deposited in the intake passage 2, and of the adhering fuel xi, a
It is thought that it can only be inhaled through vaporization.

Then, the following equation holds true for the amount of intake yi into the combustion chamber 1 and the increase in the amount of adhesion to the inner wall surface of the intake passage (X-XI).

y, t= a X1+ b u, t" (1) Xi+1-
x1= (1-b)u, 1-a xl" (2) Further organizing, x1= (1-a)xt-t+ (1-b)ui-x"
(3) becomes.

Next, we extend the above theory to fuels with multiple compositions.

The adhesion amount vector for each component is χ1, the intake amount vector for each component is y, and the vaporization coefficient matrix for each component is AA (this AA is the diagonal component a.+azz+・
・A matrix in which tann is the vaporization coefficient a1t azt...an in sequence, and the other parts are O, and the weight ratio of each component x direct inhalation rate is set as a vector, and the weight ratio matrix for each component is W (this W is the diagonal component W
i,,W,,...Wnn are sequentially weight ratio coefficients w,,w,
, ..., Wyl, and the other parts are O), then for multicomponent fuel, xi= (1-AA)
ui, 1”(4)yl=AAxl+TotWul”(5
) holds true.

Here, e is a unit vector and ■ is a unit matrix.

Next, the estimation of the 1-equivalent octane number will be explained.

First, let α be a vector in which αJ is the octane number of each component. For some types of fuel, the equivalent octane number can be determined by the sum of (weight ratio x octane number), so
Approximately, the following formula can be used.

0NL= t tyt/ etyt゛-(6) Here,
ONi is the equivalent octane number at time i, and t is the transpose of the vector.

In this way, equivalent octane numbers for fuels of multiple compositions can be determined.

Note that if the error in equation (6) is large, use a data table in which the octane numbers for each weight ratio are determined in advance. In this case, 0Ni=f (gty) (7).

Next, the ignition timing calculation procedure will be explained using the flowchart in FIG. 3.6 First, in step a1, the vaporization characteristics of each fuel component
The octane number is read, the amount of injected fuel is measured in step a2, and the vaporization/intake model as described above is calculated from this information in step a3, thereby obtaining the adhesion amount vector χ1 for each component. Inhalation amount Vi for each component
seek.

Next, in step a4, the equivalent octane number is calculated, and in step a5, the engine speed and load parameters are taken in. In step a6, the ignition angle is calculated as the equivalent octane number and the engine speed.

Determined by engine load.

Then, when the ignition angle is determined as described above (this ignition angle is calculated for each ignition timing), the power transistor 11 is
An ignition signal is sent to the ignition signal, and the ignition plug 9 ignites at a timing corresponding to the ignition signal.

In this way, the equivalent octane number during combustion within 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 this equivalent octane number. Optimum ignition timing control for improving output and fuel efficiency can be achieved without delaying the ignition angle. In particular, since it is possible to always set the optimal ignition angle that will not cause knock during acceleration, it is possible to reliably prevent knock during acceleration while minimizing the hindrance to rapid acceleration, and thereby increase engine output. This increases engine efficiency and significantly improves acceleration performance.

The ignition timing calculation means 23 is provided with an ignition timing map for the nominal octane number, and if the estimated octane number does not deviate much from the nominal octane number, the ignition timing map for the nominal octane number is used to calculate the estimated octane number. It is also possible to correct the ignition timing only when the octane number determined is significantly different from the nominal octane number.

Furthermore, when controlling the ignition timing, corrections may be added in accordance with the water temperature and the intake air temperature.

Further, the ignition timing calculation means 23 is configured with a basic ignition timing setting means, an ignition timing correction amount setting means, and an addition means for adding the information obtained by these means, so that The ignition timing may be corrected by an ignition timing correction amount obtained according to the equivalent octane number and used as the ignition timing information.

Furthermore, the present invention can be applied to engines that can use a plurality of fuels with different octane numbers, such as engines that can use either gasoline fuel or alcohol blend fuel, with the same device.

Furthermore, the present invention applies not only to spark-ignition internal combustion engines that use the Jetro method using an air flow sensor, but also to spark-ignition internal combustion engines that use the D-Jetro method (speed density method) that uses an intake passage pressure sensor. It is applicable.

[Effects of the Invention] As detailed above, according to the ignition timing control device for a spark-ignition internal combustion engine of the present invention, using a required mathematical model,
The octane number during combustion in the combustion chamber can be estimated in real time, and ignition timing information can be obtained based on this estimated octane number, so the ignition timing can be optimized to improve output and fuel efficiency without unnecessarily delaying the ignition angle. Ignition timing control can be realized, and even when the octane number decreases, especially during acceleration, appropriate ignition timing information can be retrieved.

This allows you to always set the optimum ignition angle that will not cause knock, so you can reliably prevent knock during acceleration while ensuring that rapid acceleration is not hindered as much as possible.As a result, you can increase engine output and improve engine efficiency. This has the advantage of increasing acceleration performance and significantly improving acceleration performance.

[Brief explanation of the drawing]

1 to 3 show an ignition timing control device for a spark ignition internal combustion engine as an embodiment of the present invention. FIG. 1 is an overall configuration diagram showing the control system and a schematic engine system. A diagram explaining the combustion octane number estimation model,
FIG. 3 is a flowchart for determining the ignition timing. Consists of 1-combustion chamber, 2-intake passage, 3-exhaust passage, 4-intake valve, 5-exhaust valve, 6-air cleaner, 7-throttle valve, 8-electromagnetic valve (injector), 9-ignition device Spark plug, 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 - Supply fuel amount Measuring means, 21--vaporization characteristics/octane number setting means, 2
2-octane number estimation means, 22A-vaporization/intake estimation means, 22B-equivalent octane number calculation means, 23-ignition timing calculation means, 23-1.23-n-ignition timing map,
24-Ignition signal generating means, (igniter operating means), E-
engine. Figure 2

Claims (1)

[Claims] The engine is equipped with an ignition timing setting means for setting the ignition timing according to the operating state of the spark ignition internal combustion engine, and an ignition device operating means for operating the ignition device based on the ignition timing information set by the ignition timing setting means. The ignition timing setting means includes a supply fuel amount measuring means for measuring the amount of fuel supplied to the internal combustion engine, a supply fuel amount obtained by the supply fuel amount measuring means, and vaporization preset for each component of the fuel. Octane number estimating means for estimating the octane number of the fuel in the combustion chamber based on each information about the characteristics and the octane number;
An ignition timing control device for a spark-ignition internal combustion engine, comprising: ignition timing calculation means for calculating the ignition timing based on the octane number estimated by the octane number estimation means.