Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
2002-08-06
2004-01-27
Solis, Erick (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
C701S104000, C701S115000, C123S674000
Reexamination Certificate
active
06681745
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel injection apparatus for an internal combustion engine for controlling a fuel injection quantity on the basis of data corresponding to CO (carbon monoxide) regulating correction quantities. More particularly, the present invention is concerned with a fuel injection apparatus for an internal combustion engine in which data input processing and data search processing are moderated while the amount of data to be held is decreased for thereby realizing implementation of the fuel injection apparatus at a low cost without impairing accuracy of the fuel injection control.
2. Description of Prior Art
In general, in the fuel injection apparatus for the internal combustion engine, the fuel injection quantity is arithmetically determined or calculated in dependence on the operation state of the internal combustion engine determined on the basis of the detection information outputted from various type of sensors. In that case, with a view to decreasing the discharge quantity of CO (carbon monoxide) contained in the engine exhaust gas, a basic fuel injection quantity is additively corrected with map data (CO regulating correction quantity data) which also depends on the operation state of the engine, whereby the fuel injection quantity is optimally adjusted or regulated.
Through the procedure mentioned above, influence of dispersion of the engine and the various types of sensors can be canceled out or compensated for, and thus it becomes possible to control the fuel injection quantity with high accuracy in conformance with the operation state of the engine.
For better understanding of the concept underlying the present invention, description will first be made of a conventional fuel injection apparatus for an internal combustion engine known heretofore.
FIG. 4
of the accompanying drawings is a block diagram showing schematically and generally a conventional fuel injection apparatus for the internal combustion engine.
Referring to
FIG. 4
, the internal combustion engine (hereinafter also referred to simply as the engine) is provided with various types of sensors for detecting the operation state of the engine, as generally designated by a reference numeral
10
, a control unit which may be constituted by a microprocessor or microcomputer
20
for arithmetically determining engine control quantities in dependence on the operation states of the engine, and a fuel injector
30
for injecting fuel into the engine.
The various types of sensors
10
include a throttle position sensor
11
for detecting an opening degree Th of a throttle valve (not shown) and a crank angle sensor
12
for detecting a rotation number or speed Ne [rpm] of the engine. The throttle opening degree Th and the rotation speed Ne [rpm] of the engine are inputted into the microcomputer
20
together with other sensor information indicative of the operation state of the engine.
The microcomputer
20
incorporates an EEPROM (Electrically Erasable and Programmable ROM)
21
as a storage means for storing or holding therein the results of the arithmetic operations (i.e., various control quantities).
Further, connected to the microcomputer
20
is an external terminal unit
40
which may be constituted by a computer so that bi-directional data communication can be effectuated between the external terminal unit
40
and the microcomputer
20
through the medium of a serial communication interface.
Set previously in the EEPROM
21
which belongs to the microcomputer
20
are basic fuel injection quantities in correspondence to the operation states, respectively, of the engine.
In this conjunction, it should be added that the EEPROM
21
also serves as a data map means for holding individual data (described later on) corresponding to the CO regulating correction quantities in a plurality of areas as determined in dependence on the throttle opening degree Th and the engine rotation speed Ne [rpm].
The microcomputer
20
is comprised of a basic fuel injection quantity arithmetic means for calculating (i.e., arithmetically determining) basic quantity of fuel injected from the fuel injector
30
on the basis of the operation state of the engine and a correcting arithmetic means for arithmetically determining the fuel injection quantity by additively correcting the basic fuel injection quantity with the data corresponding to the relevant area of the EEPROM
21
.
The microcomputer
20
is so arranged as to reference the data values stored in the EEPROM
21
on the basis of the operation state determined from the output of the various types of sensors
10
to thereby arithmetically determine the final fuel injection quantity.
Next, referring to
FIGS. 5
to
7
of the accompanying drawings together with
FIG. 4
, description will be directed to the fuel injection quantity control operation carried out by the conventional fuel injection apparatus for the internal combustion engine.
FIG. 5
is a flowchart for illustrating a fuel injection quantity calculation routine executed by the microcomputer
20
.
Further,
FIG. 6
is a view for illustrating a data map of the CO regulating correction quantity known heretofore, and
FIG. 7
is a view for illustrating data values at individual points based on the data map shown in FIG.
6
.
Referring to
FIGS. 6 and 7
, data D
1
to D
16
for the CO regulating correction quantity are arrayed in a three-dimensional data map with the throttle opening degree Th and the engine rotation speed Ne [rpm] being used as parameters, wherein sixteen areas determining the individual data D
1
to D
16
, respectively, result from division by four throttle opening degrees Th
1
to Th
4
on one hand and four engine rotation speeds Ne
1
to Ne
4
on the other hand.
At this juncture, it is noted that the relation among the throttle opening degrees Th
1
to Th
4
is given by
Th
1
<Th
2
<Th
3
<Th
4
.
Further, relation among the engine rotation numbers or speeds Ne
1
to Ne
4
is given by
Ne
1
<Ne
2
<Ne
3
<Ne
4
.
In more concrete, the throttle opening degrees and the engine rotation speeds may be set, by way of example, as follows:
Th
1
=10 [deg]
Th
2
=12 [deg]
Th
3
=30 [deg]
Th
4
=32 [deg]
Ne
1
=3000 [rpm]
Ne
2
=3200 [rpm]
Ne
3
=4500 [rpm]
Ne
4
=4750 [rpm]
In the exemplary case mentioned above, in the area for the data D
1
shown in
FIG. 6
, the throttle opening degree Th is not greater than Th
1
[deg] with the engine rotation speed Ne being not greater than Ne
1
[rpm]. This area thus corresponds to an idling and low-speed operation range.
Further, in the areas corresponding to the data D
4
, D
8
and the like, the engine rotation speed is not higher than Ne
4
[rpm] and represent a high-speed operation range.
Further, the data D
2
, D
3
and the like are represented by point data values (see
FIG. 7
) in point regions determined by the throttle opening degree and the engine rotation speed. In this case, the data value within a range of the engine rotation speeds [rpm] Ne
2
to Ne
3
can be determined through a linear interpolation calculation between two points.
Furthermore, in
FIG. 7
, individual CO regulating correction quantity data values exist at the prints (grids), respectively, which are determined by the throttle opening degrees Th
1
to Th
4
and the engine rotation speeds [rpm] Ne to Ne
4
, respectively.
Now referring to
FIG. 5
, the basic fuel injection quantity and the various correcting values for the basic fuel injection quantity are arithmetically determined or calculated on the basis of the input information from the various types of sensors
10
(indicating the engine operation state) in a step S
1
, which is then followed by a step S
2
where the CO regulating correction quantity conforming to the throttle opening degree Th and the engine rotation speed Ne [rpm&
Mitsubishi Denki & Kabushiki Kaisha
Solis Erick
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