JPH03217645A - Control value calculation - Google Patents

Abstract

PURPOSE:To calculate a target control value with a small memory capacity by determining maximum and minimum control values and compensation coefficient with a pair of mapping and interpolation mapping for two variables and the third variable, and using a particular equation. CONSTITUTION:In the engine control of a FFD vehicle, for example, an engine 10 is controlled by a controller 25. A control program, two three-dimensional mappings and respective control value calculation mapping are memorized in the memory circuit 40 of the controller 25. The most suitable ignition timing for air-fuel ratio and engine speed of two variables is memorized in the three- dimensional mapping for maximum and minimum values. The interpolation coefficient K based on the blend rate which is the third variable is calculated with interpolation mapping. A target control value D is calculated according to D=D0+(K/100)(D100-D0) as the most suitable blend rate from the maximum and minimum values D100, D0 of the blend rate by a control circuit 39 in the controller 25. It is thus possible to calculate the most suitable value with a small capacity memory.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for calculating control values performed by a control means installed in a control device using a data map.

(Prior art) A control means installed in a control device, for example, an engine controller attached to an engine, calculates a control value based on each input information, and drives a control actuator with an output corresponding to the first shift. and performs the necessary control processing.

However, when a controller calculates a control value from input information, it often uses a calculation formula set in advance, or uses a map to calculate a value that matches each characteristic.2 For example, A normal vehicle has various data maps in its controller to calculate the control value of the ignition timing.As shown in Figure 5, this ignition timing map is based on the intake air amount A/N and the engine speed N. The ignition timing D is determined from two variables, and this map is stored in the memory circuit of the controller as each ignition timing map for regular gasoline or high-octane gasoline.

(The problem that Yumei is trying to solve) Recently, there has been a development in which vehicles can automatically detect the blend ratio, which is the mixture ratio of methanol and gasoline, and can run on that mixed fuel, in other words, there is flexibility in the fuel used. (hereinafter simply FF
It has been proposed to introduce a

Due to the differences in the stoichiometric air-fuel ratio, octane conversion, calorific value, etc. of methanol and gasoline, it is necessary to set various control data maps for each different blend ratio to perform optimal control. do not have.

Therefore, it is also necessary to prepare an ignition timing map for every 10% increase in blend ratio from 0% to looqr.

That is, it is necessary to prepare ignition timing maps for each blend ratio for each 10% increase as shown in FIG. 6.7 In this case,
One map requires 10xlOxlbyt, and l1 maps require more than I Kbyt. Moreover, in addition to the ignition timing map, the controller is also equipped with various correction coefficient calculation maps used for calculating the fuel injection amount, and if these maps are also provided with an ignition timing map every time the blend ratio changes, the controller's Memory is required to have an extremely large capacity, which is becoming a problem.

An object of the present invention is to provide a control value calculation method that can calculate target control values over a relatively wide range using a memory with a relatively small storage capacity.

(Means for Solving the Problems) In order to achieve the above object, the present invention is capable of calculating control values according to two different variables, and each control value is set based on the maximum and minimum values of a third variable. A pair of maximum/minimum three-dimensional maps, and interpolation that can calculate each set interpolation coefficient according to each set interval value obtained by dividing the maximum and minimum values of the third variable by a set amount. map and
a control means for calculating the control value from the source of the third variable; A pair of maximum and minimum control values D4 based on each particular element of three different variables.

. , Do are respectively calculated from the pair of maximum/minimum three-dimensional maps, and then the target control value D for a specific element of the third variable is calculated using the following formula D=D0+(K/100)(D). -Do).

(Operation) The control means calculates an interpolation coefficient K based on a specific element of the third variable from the interpolation map, and calculates a pair of maximums based on each specific element of two different variables using a pair of maximum/minimum three-dimensional manob. Minimum control value D. . , Do is calculated, and then the target control direction D is calculated using the following formula D = Do + (K/too) (D, . . 1 D.) (Example) Below, the six inventions The following describes a control 1-direct calculation method.

In this control value calculation method, as shown in FIG.
, 2, interpolation maps 3 and 5, and a control means 4 that calculates a control value D from the third variable 2 is used.

Here, a pair of maximum and minimum three-dimensional maps Mzmin,
Mzmax 1 and 2 can calculate control values D according to two different variables xy, and each control value D is set based on the maximum and minimum values z min and zmax of the third variable 2.

The interpolation map 3 is a two-dimensional map, and each set interval value z n . z (n+1),
Each interpolation coefficient -0 according to z (n+2)...
... is set.

An interpolation coefficient calculation device 5 in the control means 4 first calculates an interpolation coefficient Kn based on a specific element zn of the third variable Z based on the interpolation map 3. Similarly, the maximum/minimum control value calculation means 6 in the direct calculation means 4 calculates a pair of maximum/minimum control values D based on specific elements of two different variables xy from a pair of maximum/minimum three-dimensional maps 1 and 2. . , Do are calculated respectively.

After this, the control value calculation means 7 uses K. D, Oo, Do?
Substituting one value into equation (1), the specific element zn of the third variable
Calculate the target control value D for.

D=D. +(K/100)(D■..-D.)-...(
Calculate and output based on 1).

Next, an ignition timing control device for an FFV vehicle that employs the control value calculation method of the present invention will be described below.

First, the engine control system for the FFV vehicle will be briefly explained with reference to FIG. 2.

Here, the combustion chamber 11 of the engine 10 has an intake FfpI12
and the exhaust passage 13 in a timely manner. The intake passage 12 is connected to an air cleaner 14. The exhaust passage 13 is formed by the first intake pipe 15, the expansion pipe 16, and the second intake pipe 17, and the exhaust passage 13 is formed by the first exhaust pipe 18.
, a second exhaust pipe 21), and a muffler 21.

Inside the air cleaner 14, an air flow sensor 22 that outputs passing air amount information, an atmospheric pressure sensor 23 that outputs atmospheric pressure information, and an atmospheric temperature sensor 24 that outputs air temperature information are arranged, and these are connected to the engine control unit (hereinafter referred to as (simply referred to as a controller) 25.

A throttle valve 26 is installed inside the expansion pipe 16, and a throttle position sensor 27 is provided opposite to the valve.Moreover, this throttle valve 26 has its idle position determined by an idle speed control motor (ISC motor) 28.
It is configured to be controlled by the controller 25 via the controller 25.

A water jacket is provided opposite to a part of the second intake pipe l7, and a water temperature sensor 29 is attached thereto.

In the middle of the first exhaust pipe 18 is an O. which outputs information on changes in oxygen concentration in the exhaust gas. , a sensor 30 is installed at the end, and a fuel injection valve 31 is installed at the end of the intake air 112. The second fuel injection valve 31 is connected to a fuel pipe 33 via a branch pipe 32.
Connected to ;tt. This fuel pipe 33 is the fuel pump 3
4 and the fuel tank 35, and in the middle: 2 is the blend rate sensor 43 and the fuel pressure regulator 36 for adjusting the fuel pressure.
It is installed nine times. Note that the blend rate sensor 43 is
A well-known configuration is used in which fuel blend ratio information that changes depending on the refractive index is detected by an optical system, and the change in the amount of light is photoelectrically converted and output to the controller 25. Further, the regulator 36 here is configured to be able to increase or decrease the fuel pressure depending on the boost pressure.

An ignition plug 46 is attached to the combustion chamber 11 of the engine 10, and the plug 46 is connected to an ignition circuit 45 consisting of a power transistor (not shown) and an ignition coil that is driven to open and close by the power transistor. It is connected to a drive circuit 44 for ignition, which will be described later.

In FIG. 4, reference numeral 37 indicates a crank angle sensor that outputs crank information, and reference numeral 38 indicates a top dead center sensor that outputs top dead center information of the first cylinder.

The controller 25 includes a control circuit 39, a memory circuit 40, an input power circuit 41, and drive circuits 42 and 44.

Here, the control circuit 3I1 receives each input signal from each sensor, and executes a predetermined control program! , and outputs a control signal.

The memory circuit 40 stores a well-known main routine for engine control,
Various control programs such as the ignition timing calculation routine shown in Fig. 4 and the fuel injection routine (not shown), as well as those shown in Fig. 3(a),
The two three-dimensional maps 47 shown in (b) and (C),
48, one two-dimensional map 49, and other control value calculation maps are stored.

Furthermore, the area for capturing correction coefficients, calculated data, and other values used during control is reduced.

Here, the three-dimensional map for maximum and minimum M Z Inl n
H M Z ma : ('. 7 and 48 are two variables, respectively, air-fuel ratio A/N. Optimum ignition timing data according to the engine speed Ne is stored. In particular, the minimum three-dimensional map Mzmin The data with a blending rate of 0 is stored in the maximum three-dimensional map Mzmax2, and the data with a blending rate of 100 is stored in the maximum three-dimensional map Mzmax2.Interpolation map 4
The first is a set value for the blend rate B, which is the third variable, and here it is divided into 10 sections, and a different interpolation coefficient is set for each section value. An appropriate value for this engagement is set in consideration of the characteristic that as the blend ratio increases, the amount of methanol that can delay the ignition timing increases.

The input/output circuit 41 operates to take in the output signals of the above-mentioned sensors as appropriate, and also outputs a valve drive signal to open the fuel injection valve 31 at a predetermined time via the valve drive circuit 42 or to the ignition circuit 45. The ignition signal is outputted via the drive circuit 44, and other control signals are outputted via a non-illustrated control circuit.

Here, ignition timing control will be explained with the control circuit 39 in the controller 25 being regarded as a control means.

When a key switch (not shown) of the engine is turned on, the controller and each sensor are driven, and the main routine is executed. Then, the ignition timing calculation routine is reached.

Here, the controller 25 first takes in the latest data of the air-fuel ratio A/N and the engine speed N5, and also takes in the blend ratio B (here, 37)7, and then creates a maximum/minimum three-dimensional map Mzmin. Mzmax47
, 48, the maximum and minimum values D of the blending ratio according to the current data. (Here it is 27>, 0e. (Here it is 4
5).

When step a4 is reached, the interpolation coefficient at the set interval value B=30 before and after the current blend rate 37 is 20, and the set interval value B=
The interpolation coefficient for 40 is 47, which is calculated from the rain map 47.48. Therefore, the interpolation coefficient K at B=37 is K=20+
7710(47-20)=38.9.

Furthermore, when step a4 is reached, the formula below becomes D. , D. .

, K.

D=D0+(K/100)(D,,,-D.)=27+
(38.9/too) (45-27) = 34.0 When the calculation of the optimal ignition timing is completed in this way, the process returns to the main routine, and the other
A valve opening signal to open the valve at a predetermined time is applied via the valve drive circuit 42, or the ignition circuit 4 is activated every time a set time limit is reached.
5 through the drive circuit 44, and performs other control processing.

In the above control value calculation method, the ignition timing is used as a control value, and it is explained that this is determined as the optimum value for each blend ratio, but other control values such as fuel injection amount, etc., or various correction coefficients, etc. The present invention can also be adopted when calculating .

(Effects of the Invention) As described above, in the method of the present invention, only three maps, the three-dimensional maps Mzmin and Mzmax for maximum and minimum, and the interpolation coefficient map are provided, and the third variable can be obtained by dividing the third variable into set amounts. Data for each set interval value can be calculated, and optimal control values can be calculated in detail without excessively increasing the memory capacity.

[Brief explanation of drawings]

Fig. 1 is a block diagram explaining the method of the present invention, Fig. 2 is a schematic configuration diagram of an engine control device adopting the method of the present invention, and Fig. 3 (a), (b), and (c) are in Fig. 2. FIG. 4 is a flowchart of the ignition timing calculation routine included in the controller in FIG. 2, FIG. 5 is an explanatory diagram of the characteristics of the ignition timing map, and FIG. shows an explanatory diagram of a conventional three-dimensional map. 1,47, 2,48...3D map, 3,49
...Interpolation coefficient map, 4...Control means, 39...
Control circuit, 25... Controller, K... Interpolation coefficient, D... Control value. Chi7 mouth

Claims (1)

[Claims] A pair of maximum/minimum three-dimensional maps capable of calculating control values according to two different variables and in which each control value is set based on the maximum/minimum value of a third variable; An interpolation map that can calculate each set interpolation coefficient according to each set interval value obtained by dividing the maximum and minimum values of the variable by a set amount, and the above control value from the third variable. The control means calculates at least an interpolation coefficient K based on a specific element of the third variable from the interpolation map, and also calculates a pair of interpolation coefficients K based on specific elements of the two different variables. Maximum and minimum control value D_1_0_0
, D_0 are calculated from the pair of maximum/minimum three-dimensional maps, and then the target control value D for a specific element of the third variable is calculated using the following formula D=D_0+(K/100)(D_1_0_0-D_0
) A control value calculation method characterized by calculating based on the following.