JPH0544490A - Supercharging pressure control method for engine - Google Patents

Abstract

PURPOSE:To enable setting of target supercharging pressure which is adequate to engine in accordance with changes of various running environment by setting target supercharging pressure whose characteristics differ per running mode three-dimensionally based on the results of judgement of running mode which is obtained by applying fuzzy theory. CONSTITUTION:An engine ECU4 and an automatic transmission ECU5 are connected to a power plant 1 which consists of an engine 2 and an automatic transmission 3, and a computer 6 for setting target supercharging pressure is connected to the ECU4 and ECU5. When target supercharging pressure is set, parameters for judging running mode are computed based on input values of various engine data and automatic transmission data. Next, degree of satisfaction is computed in parallel depending on running mode from membership function of fuzzy control theory which is set per running mode based on the parameters for judging each mode. Running mode of vehicle is judged at real time based on the degree of satisfaction of each running mode, and target value of supercharging pressure is set based on the running mode which is judged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercharging pressure control method for an engine, which determines a driving mode of a vehicle by using a fuzzy theory and determines a target value of the supercharging pressure.

[0002]

2. Description of the Related Art Conventionally, various technologies relating to supercharging pressure control of engines have been proposed. For example, in Japanese Utility Model Publication No. 61-10935 and Japanese Utility Model Publication No. 61-160235, engine load and engine The method for controlling the supercharging pressure of the engine, which controls the supercharging pressure according to the operating state of the engine, is shown.

Further, in Japanese Patent Application Laid-Open No. 63-208634, an engine capable of changing a supercharging region given by an engine load and an engine speed to control a supercharging pressure in response to more complicated changes in engine operating conditions. The supercharging pressure control method of is shown.

That is, a plurality of types of supercharging characteristics of the supercharger are set and stored in advance, and the power mode or the economy mode is appropriately selected according to the driver's selection, and the supercharging according to the operating state of the engine is performed. The pressure control can be performed.

However, the above technique does not change the supercharging pressure itself but only the region of whether or not the supercharging is performed. Therefore, the optimum target supercharging pressure is set according to the operating state. Cannot be set. For example, it is not possible to separately set the appropriate target boost pressure for the engine according to changes in the traveling environment such as mountain climbing, mountain descending, high speed traveling, urban traveling and traffic congestion.

Further, for example, when the supercharging characteristic is selected when traveling on a mountain climbing road and when traveling on a traffic jam, the driver has to switch the switch, which is very troublesome.

By the way, at present, fuzzy control as an application of fuzzy theory is performed in various fields.

The applicant of the present invention also proposed in Japanese Patent Application No. 3-95778 a driving mode judging method which applies a fuzzy theory which enables the driving mode to be judged accurately in real time according to the driver's sensitivity. There is.

However, the above-mentioned technique attempts to determine the traveling mode by applying the fuzzy theory, and merely proposes an application example of the determined traveling mode.

[0010]

As described above, in the conventional supercharging pressure control method for an engine, the supercharging region can be changed so that the supercharging pressure characteristic can be selected with respect to the change in the engine operating state. However, it is not possible to separately set the appropriate target boost pressure for the engine according to various changes in the driving environment, and it is necessary to provide a means for the driver to change the switch, etc. Could have been a factor.

On the other hand, the technique capable of determining the traveling mode by applying the fuzzy theory to determine the traveling mode corresponding to the driver's sensitivity merely proposes an application example of the determined traveling mode.

The present invention has been made in view of the above circumstances, and as a specific application technique based on the traveling mode determination result that can be obtained by applying the fuzzy theory, it can be adapted to various traveling environment changes. The target supercharging pressure can be set separately for each engine, and a supercharging pressure control method for an engine with extremely high drivability that does not require a driver's switch changeover or the like is provided. The purpose is to do.

[0013]

In order to achieve the above object, a method for controlling supercharging pressure of an engine according to the present invention is a procedure for calculating a physical quantity during driving based on a driving state of a vehicle, and using this physical quantity as an input variable. A procedure for calculating the satisfaction degree from the membership function of the fuzzy theory set for each traveling mode, a procedure for determining the traveling mode of the vehicle in real time based on the satisfaction degree for each traveling mode, and a procedure for determining the traveling mode determined above It is provided with a procedure for determining the target value of the boost pressure and a procedure for outputting based on the determined target value of the boost pressure.

[0014]

[Operation] In the supercharging pressure control method for an engine according to the present invention, first, a physical quantity during driving is calculated based on the driving state of the vehicle, and the physical quantity is set as an input variable from the membership function of the fuzzy theory set for each running mode. Calculate each satisfaction.

Then, the running mode of the vehicle is judged in real time based on the satisfaction of each running mode, the target value of the supercharging pressure is determined based on the judged driving mode, and the determined supercharging pressure is determined. The target boost pressure is output based on the target value.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a flowchart showing a procedure for setting a target supercharging pressure, FIG. 2 is a system schematic diagram, FIG. 3 is a running mode determination system block diagram,
FIG. 4 is a schematic diagram of membership functions by traveling mode, and FIG. 5 is a schematic explanatory diagram of a target supercharging pressure map.

Reference numeral 1 in FIG. 2 denotes a power plant, which is an engine (E / G) 2 and an automatic transmission (A /
T) 3 and this engine 2 and automatic transmission 3
E / GECU with data communication function that can communicate with each other
4, A / T ECU5 is connected. Also, both EC
The target boost pressure setting computer 6 is connected to U4 and U5.

Next, the target supercharging pressure setting procedure in the target supercharging pressure setting computer 6 will be described with reference to the flowchart of FIG.

The steps 101 to s105 in the flowchart (hereinafter abbreviated as "S") are a running mode judging program to which the fuzzy theory is applied. This running mode judging procedure is particularly shown in FIG. This will be described with reference to the system block diagram.

The target supercharging pressure setting procedure is executed every predetermined calculation cycle.

First, the system is initialized in S101, and the engine data obtained from the E / GECU 4 is input in s102.

As the engine data, (a) engine speed N, (b) basic fuel injection pulse width Tp, (c) switch input (key switch, starter switch, air conditioner switch, neutral switch, parking switch, Idle switch, full accelerator switch, etc.).

Next, in s103, the automatic transmission data obtained from the A / TECU 5 is input.

As the automatic transmission data,
There are (d) vehicle speed VSP, (e) shift (1st to 4th speed, etc.), and (f) brake switch.

After that, in s104, the drive mode determination parameter (physical quantity) is calculated based on the above input values.

This traveling mode determination parameter is (1)
Average vehicle speed every 10 seconds (10S), (2) average vehicle speed every 60 seconds (60S), (3) travel distance from stop, (4) travel distance to stop, and (5) climbing resistance.

The parameters for determining each driving mode are obtained from the following equations.

(1) 10S average vehicle speed: VAVE10 [Km / h] VSP: Vehicle speed [Km / h] SAMPT: Calculation cycle [S] (Sample time) (2) 60S Average vehicle speed: VAVE60 [Km / h] (3) Travel distance from stop: DTSA [m] DTSA = Σ (VSP ・ (1000/3600) ・ SAMPT) (4) Travel distance to stop: DTSBAK [m] DTSBAK ＝ DTSA (VSP = 0) (5 ) Climbing resistance 30S average: FAVE [Kgf] FEX ＝ F- (REI + RAI) F ＝ TETP ・ IM ・ IF ・ (ET / r) ・ ETR ・ ETI FEX: Uphill resistance [Kgf] F: Driving force [Kgf] REI: Running resistance [Kgf] RAI: Acceleration Resistance [Kgf] TETP: Net engine torque [Kgf ・ m] IM: Transmission gear ratio IF: Final reduction ratio ET: Transmission efficiency r: Tire effective radius [m] ETR: Torque converter torque ratio ETI: Torque converter efficiency Then, in s105, the above-mentioned mode determination parameter VAVE1
Based on 0, VAVE60, DTSA, DTSBAK and FAVE, the satisfaction function for each driving mode is calculated in parallel from the membership function of the antecedent part of the fuzzy control set for each driving mode, and the minimum satisfaction value MIN in each driving mode is calculated. Is determined as the degree of satisfaction of the driving mode.

As shown in FIG. 4, the driving modes in this embodiment are: (1) super high speed (2) normal high speed (3) high speed traffic jam (4) suburban road (5) mountain climbing (6) mountain There are 9 modes of downhill (7) city road (8) city congestion (9) stop, and membership functions for each driving mode and each driving judgment parameter are obtained in advance by experiments and tabulated.

Referring to FIG. 4, for example, when looking at the ultra-high speed mode, the travel determination parameter is VAVE10 = 90 [Km /
h], VAVE60 = 100 [Km / h], and DTSA = 700 [m], VAVE10 satisfaction is 0.5, VAVE60 satisfaction is 1.0, DT
The SA satisfaction is 0.4, so the minimum value MIN is
Since it is 0.4, the satisfaction degree of the travel distance DTSA from the stop is the satisfaction degree in the super high speed mode.

Then, such mode satisfaction determination is calculated in parallel for each of the traveling modes.

After that, the minimum value MIN for each traveling mode obtained by the mode satisfaction determination is compared, and the mode having the maximum value MAX among them is determined to be the traveling mode in the current traveling state.

The vehicle speed is displayed on the display, recording paper, etc.
Display the current driving mode together with various data such as VSP and proceed to s106.

As described above, the membership function for calculating the degree of satisfaction of the parameters in each traveling mode can be set separately for each traveling determination parameter, and the relationship with other modes and other parameters need not be adjusted. Therefore, it is possible to obtain a macro determination result corresponding to the traveling change. Therefore, it is possible to flexibly deal with the increase and decrease of the traveling mode and the increase and decrease of the parameters.

As a result of the running mode judgment in this way, the running mode judgment ability is 90% or more, that is,
Judgment results were obtained that were almost suitable for actual running, and the time required for judgment was within 10 [s].

Next, in S106, it is determined whether or not the determined traveling mode is the mountain climbing mode. If it is the mountain climbing mode, the process proceeds to S108. If it is not the mountain climbing mode, the process proceeds to S107. , It is determined whether or not the determined traveling mode belongs to any one of mountain downhill, high speed traffic jam, urban traffic jam and stop mode, and if any of these modes, proceed to S109, and If none of the modes (super high speed, normal high speed, suburban road and city road mode), proceed to S110.

Here, steps S108, S109 and S110 are steps for indexing the target supercharging pressure map MP created in advance corresponding to each step and setting the target supercharging pressure. ing.

The target supercharging pressure map MP is, for example, as shown in FIG. 5, a three-dimensional map for setting the basic supercharging pressure by the engine speed N and the accelerator opening (throttle opening). If it is determined that the vehicle is in the mountain climbing mode in S106 and the process proceeds to S108, the target supercharging pressure is calculated from the map MP1 forming the uppermost surface (maximum supercharging pressure portion) in FIG.
And the accelerator opening.

Further, in S107, it is determined that the vehicle belongs to one of the mountain descending slope, the high speed traffic jam, the city traffic jam and the stop mode S1.
Proceeding to 09, the map MP2 forming the lowermost surface (non-supercharging portion) of FIG. 5 is called and no supercharging is performed.

Furthermore, in S107, it is determined that the mode is not one of mountain downhill, high speed traffic jam, urban traffic jam and stop mode (super high speed, normal high speed, suburban road and city road mode) and S110.
As shown by the broken line in FIG. 5, the map MP of the characteristic that the maximum boost pressure is obtained when the accelerator opening is ½ or more.
3 is called and the target supercharging pressure is set.

When the target supercharging pressure corresponding to each step is set in S108, S109 and S110, the process proceeds to S111, the supercharging pressure control actuator is duty-controlled, and the program is terminated.

As described above, by effectively combining the driving mode determination applying the fuzzy theory and the setting of the target supercharging pressure, the supercharging pressure map emphasizing the output is used at the time of mountain climbing, and the engine It is possible to drive with maximum output, and fuel efficiency is emphasized when driving downhill mountains, high-speed traffic jams, urban traffic jams, and when stopped, so it is possible to prevent unnecessary supercharging due to rough accelerator operation and improve fuel efficiency. Can be made Furthermore, even in other running conditions,
Since the optimum target supercharging pressure can be obtained in the running state, it is possible to achieve an appropriate output and an improvement in fuel consumption.

Since the target supercharging pressure is automatically set, the driver does not have to bother with the switch operation, and a comfortable ride that is suitable for the driver can be obtained.

In this embodiment, the target boost pressure map MP
Map MP1 in mountain climbing mode, mountain downhill, high speed traffic jam, city traffic jam and map MP2 in stop mode, super high speed, normal high speed, map M in suburban road and city road mode
I used three types of P3, but for each mode,
The target boost pressure map MP may be formed by further creating a map.

[0046]

As described above, according to the present invention,
Based on the driving mode judgment results that can be obtained by applying the fuzzy theory, the target boost pressure with different characteristics is set three-dimensionally for each driving mode. Appropriate target boost pressure can be set separately for the engine, and there is no need for the driver to change the switch, etc., and a good ride comfort that matches the driver's sensitivity is obtained. It becomes possible.

[Brief description of drawings]

FIG. 1 is a flowchart showing a target boost pressure setting procedure.

FIG. 2 Schematic diagram of the system

FIG. 3 is a block diagram of a driving mode determination system

FIG. 4 is a schematic diagram of membership functions by driving modes.

FIG. 5 is a schematic explanatory diagram of a target supercharging pressure map.

Claims (1)

[Claims] 1. A procedure of calculating a physical quantity during driving based on a driving state of a vehicle, a step of calculating a satisfaction degree from a membership function of fuzzy theory which is set for each traveling mode using the physical quantity as an input variable, and Based on the satisfaction of the driving mode, the procedure of determining the driving mode of the vehicle in real time, the procedure of determining the target value of the boost pressure based on the determined driving mode, and the procedure of determining the target value of the boost pressure determined above A method for controlling supercharging pressure of an engine, comprising: a procedure for outputting.