JPH03160138A - Internal combustion engine fuel injection device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an internal combustion engine fuel injection system that allows a speed density type fuel injection amount to be determined easily and efficiently.

[Conventional technology]

FIG. 1 is a block diagram showing the structure of the internal combustion engine fuel injection system of the present invention, which will be described later. The structure of the blocks is the same as the conventional one, and this FIG. 1 will be referred to when explaining the conventional example. I will explain it as follows. In FIG. 1, 1 is an internal combustion engine, 2 is an intake pipe connected to the internal combustion engine 1, and 3 is a throttle valve provided in the intake pipe 2. In FIG.

A pressure sensor 4 is provided in the intake pipe 2 downstream of the throttle valve 3, and the pressure sensor 4 detects intake pressure.

The detection output of the pressure sensor 4 is sent to an AD (analog/digital) converter 91. Further, the rotation of the internal combustion engine l is detected as a pulse by the rotation sensor 5, and the output of the rotation sensor 5 is sent to the human power circuit 92. Further, the intake pipe 2 is provided with an injector 6, and the injector 6 injects fuel into the intake pipe 2.

The injector 6 is driven by the output of the output circuit 96 in response to instructions from the microprocessor 93. Further, a throttle angle sensor 8 for detecting the opening degree of the throttle valve 3 is connected to the throttle valve 3, and an output corresponding to the throttle opening degree is sent to the AD converter 91. 9 in FIG. 1 indicates pressure sensor 4. This figure shows a control device that calculates the required amount of fuel based on information sent from the rotation sensor 5, throttle angle sensor 8, etc., and generates drive pulses for the injector 6. AD in this control device 9
The converter 9l converts analog signals from the throttle opening sensor 8 and pressure sensor 4 into digital values and sends them to the microprocessor 93. Further, the human power circuit 92 converts the level of the pulse output signal of the rotation sensor 5 and sends the output to the microprocessor 93.

Microprocessor 93 calculates the amount of fuel to be supplied to internal combustion engine 1 based on the digital and pulse signals obtained from AD converter 9l and input circuit 92, and outputs a drive signal for injector 6 according to the result.

In the control device 9, the control iI11 of the microprocessor 93
Data is stored in advance in a ROM (read-only memory) 94, and data used in the calculation process is temporarily stored in a RAM (random access memory) 95. microprocessor 9
3, the injector 6 is driven by the output of the output circuit 96. Further, the microprocessor 93 as a basic fuel amount calculation means receives a pulse signal input from the rotation sensor 5, that is, the engine rotation speed P. and the intake pipe pressure (absolute pressure) value P obtained from the pressure sensor 4, the first coefficient (volume efficiency {a) set in the map as shown in FIG. is read from ROM94, and this first
It is obtained by multiplying the coefficient of , the intake pipe pressure value, and the injector flow rate characteristic by a second coefficient determined from the engine exhaust capacity.

[JiB to be solved by the invention] Since the conventional internal combustion engine fuel injection system is configured as described above, a large number of map points are required for the two-dimensional map, and as the capacity of the ROM 94 increases, the map The lookmap operations for this will also become complicated. In particular, if you want to improve accuracy by narrowing the map interval for a specific area, the operation becomes extremely complicated. In addition, the determination (matching) of the map value requires matching at each grid point of the two-dimensional map, which takes a huge amount of time and effort.This invention solves the above problems. The purpose of this invention is to provide an internal combustion engine fuel injection system that can accurately determine basic tPA#Jt using map points and with simple operations.

[Means to solve the problem]

The internal combustion engine fuel injection device according to the present invention is provided with a basic amount calculation means for calculating a basic fuel amount using a specific calculation formula from a one-dimensional map based on intake pipe pressure and a one-dimensional map based on rotational speed. [Operation] In this invention, the basic amount of fuel is calculated using the following formula from a one-dimensional map based on intake pipe pressure and a one-dimensional map based on rotational speed. A=BXx, ,: Fuel correction value in the rotational speed direction [Example] An example of the internal combustion engine fuel injection device of the present invention will be described below based on the drawings. Fig. 1 is a block diagram showing the configuration of one example.
As already mentioned in the ``Prior Art'' column regarding Bronok's horizontal command, I will avoid redundant explanations of ill power here, and will mainly focus on the features of this invention. Figure 2 is a diagram showing the volumetric efficiency of an internal combustion engine using intake pipe pressure and rotational speed as parameters to explain this invention. This shows the pipe pressure on the Y-axis. As shown in Fig. 2, the volumetric efficiency has an uneven curve in the rotational speed direction, but it can be seen that the shape is roughly similar even if the intake pipe pressure changes. Furthermore, it can be seen that the pressure in the intake pipe increases slowly and monotonically. From a detailed examination of experimental data? It was found that the value of the volumetric efficiency can be determined by approximate calculations from representative values in the rotational speed direction and pressure direction. That is, for example, in Fig. 2, the representative value in the rotation speed direction is 3000 rpm, and the representative value in the pressure direction is 460 mmH.
g, physical efficiency C (third
The value of (shown at point C in the figure) is obtained using the microprocessor 93 as C=XIX■Xe. Here, XO X6 Xz x++ As shown in Figure 3, The correction value is a fuel correction value in the rotational speed direction under any operating condition.

Therefore, the basic fuel amount calculated by the micro processor 93 as the basic amount calculation means is A=B
XI X XO. Here, A is the basic fuel amount B, which is determined by a value corresponding to the intake pipe pressure, cylinder volume, and injector gain, and the approximation error can be kept to about 3%. Value IO of the point where the rotation speed direction and the intake pipe pressure direction intersect
, pressure direction fuel correction in any operating state {direct xl, rotational speed direction fuel correction value X, in any operating state is the rotation axis.
Representative points on each pressure axis, e.g. pressure 460mHg
every 250 or 500 rpm on the axis of
The volumetric efficiency can be easily determined by measuring the volumetric efficiency for each mHg, and calculating the distance between measurement points by linear interpolation between two adjacent points. When calculating the basic fuel amount using the microprocessor sensor 93, the calculation processing speed should be made as fast as possible, and the ROM used should be
From the viewpoint of reducing the capacity of 94 as much as possible, it is desirable to calculate the above-mentioned X z / X 6 in advance and store it as one correction coefficient according to the rotation speed. Furthermore, since BXx+ is also a value that depends on the intake pipe and pressure value, it is desirable to store it in advance as a function of pressure. However, in this case, due to the resolution of the fuel supply amount required for the internal combustion engine (10 bits or more is required), when using an 8-bit microprocessor 93, two one-dimensional map values with different resolutions It is necessary to add it or store it as 2-byte data. [Effects of the Invention] As described above, according to the present invention, the basic injection amount is calculated using a specific arithmetic formula using a l-dimensional map based on intake pipe pressure and a one-dimensional map based on rotational speed. The basic fuel amount can be calculated using map points (ROM capacity) with high accuracy and simple operation, reducing the calculation load on the software and microprocessor, thus further improving other processing performance and reducing costs. This has the effect that it is possible to obtain an internal combustion engine fuel injection device that can perform

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the structure of a conventional internal combustion engine fuel injection system and an embodiment of the present invention. FIG. FIG. 3 is an explanatory diagram for determining the volumetric efficiency using the arithmetic formula in this invention, and FIG. This is an explanatory diagram of what is required. l... Internal combustion engine, 2... Intake pipe, 3... Throttle valve, 4... Pressure sensor, 5... Rotation sensor, 6...
...Injector, 8...Throttle opening sensor, 9
...Control device, 93...Microprocessor, 94
...ROM, 95...RAM. Fig. l Internal combustion engine intake pipe throttle valve pressure sensor rotation sensor injector throttle opening sensor control device Fig. 2 Fig. 3 2nd year September 14th

Claims (1)

[Scope of Claims] An intake pipe pressure detection means for detecting the intake pipe pressure of an internal combustion engine, a rotation speed detection means for detecting the rotation speed of the internal combustion engine, the intake pipe pressure detection means and the rotation speed detection means. In the internal combustion engine fuel injection device, the basic amount calculating means calculates the basic amount of fuel to be supplied to the internal combustion engine based on the detection result of the basic amount using the following formula. An internal combustion engine fuel injection device characterized by calculating. A= B x_2: Fuel correction value in rotational speed direction