JPS6371552A - Throttle valve opening degree detector - Google Patents

Abstract

PURPOSE:To prevent the deterioration of exhaust component and operation performance by installing a throttle valve opening degree sensor in two track system for a throttle valve and installing a controller for selecting the control signal for an engine when the throttle valve opening degree detecting means is in anomaly, thus maintaining the air fuel ratio control. CONSTITUTION:A means 2 for detecting the anomaly of a throttle valve opening degree detecting means 1 from the variation rate of the opening degree signals which a plurality of throttle valve opening degree detecting means 1 transmit is installed. A means 3 for selecting the signals of the throttle valve opening degree detecting means 1 in the normal state as the engine control signal on the basis of the detection for anomaly is installed. When cut-off is generated in the throttle valve opening degree detecting means 1, the opening degree signal varies sharply, and anomaly can he judged. Since only the signal of the throttle valve opening degree detecting means in normal state is always selected as the control signal for the engine, no influence is given into the air fuel control, and deterioration of the exhaust component and operation performance is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in a device for detecting the opening of a throttle valve in an internal combustion engine.

Conventional technology As a type of fuel injection device for gasoline engines, etc., there is one that determines the amount of intake air from the throttle valve opening and the engine speed, and controls the amount of fuel injection accordingly.
E Paper 850293J etc./This is disclosed. In this case, the throttle valve opening degree is detected using a throttle valve opening sensor consisting of, for example, a potentiometer configured to change the resistance value by sliding a brush on a printed resistor. , in low load areas such as idle, the detection error of the throttle valve opening has a very large effect on the air-fuel ratio, so the above r SAE Paper 85029
The device described in J uses a two-track type throttle valve opening sensor, which improves detection accuracy in a region where the opening is small. In other words, a throttle valve opening sensor is used that has a track with a high slope characteristic in which the sensor output changes greatly depending on the throttle valve opening, and a track with a low slope characteristic in which the change is gentle. A configuration in which the signal V8 is selectively used in a small opening region where the detected opening signal Vs is below a predetermined opening, and the signal VRfs detected by a track with a low slope characteristic is used in a large opening region where the detected opening is more than the predetermined opening. It becomes. , Problems to be Solved by the Invention For example, in the above-mentioned throttle valve opening sensor in which a brush slides on a printed resistor, the resistor may become damaged due to scratches or dirt on the sliding surface. Momentary interruptions between the brush and the brush often occur, but with the conventional device described above, abnormal detection values that occur due to momentary interruptions are read in as they are.
There is a risk that a sudden throttle valve operation (acceleration, deceleration) will be mistakenly detected and correction will be performed for transient times such as an increase in acceleration or a decrease in deceleration. Even with the two-track system mentioned above, one track is simply selected depending on the opening degree of the throttle valve, and if a momentary interruption occurs in the selected track, a similar problem will occur. do.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a plurality of throttle valve opening degree detection means 1 which generates a signal corresponding to one throttle valve opening degree as shown in FIG.・This throttle valve opening detection means 1...
Means 2 detects an abnormality in the detection means l from the rate of change of the opening signal issued by the valve opening, and based on the detection of this abnormality, a normal signal from the throttle valve opening detection means 1 is selected as the engine control signal. The present invention is characterized in that it is provided with means 3 for doing so.

If an instantaneous interruption occurs in the throttle valve opening detecting means 1, the opening signal changes rapidly, so it can be determined that there is an abnormality. At this time, the selection means 3 selects the normal signal of the throttle valve opening detection means 1 other than the one in which this abnormality was detected as the engine control signal.

Embodiment FIG. 2 is a configuration explanatory diagram showing an embodiment of a fuel injection device using the throttle valve opening detection device according to the present invention.
1 is an internal combustion engine; 12 is an intake passage 13 of the internal combustion engine 11;
The throttle valve 14 installed in the throttle valve 12 is a single-point fuel injection valve disposed upstream of the throttle valve 12.

Fuel is fed under pressure to the fuel injection valve 14 from a fuel tank 15 through a fuel filter 16, and the pressure of the fuel is maintained at a constant value by a pressure regulator 17.

Further, for the throttle valve 12, a two-track type throttle valve opening sensor 18, which will be described later, is used to detect the opening degree of the throttle valve 12.
is provided.

Reference numeral 19 denotes a crank angle sensor for detecting engine speed, which is built into the distributor 20 and is configured to emit a pulse signal at every fixed crank angle. Note that 21 represents an ignition coil, and 22 represents a battery. Reference numeral 23 denotes a control device using a microcomputer system, and this control device ff23 centrally controls the amount of fuel injection, injection timing, ignition timing, etc. in addition to detecting the opening of the throttle valve, which will be described later. .

3 and 4 show a specific configuration of the throttle valve opening sensor 18. As shown in FIG. This throttle valve opening sensor 18 is connected to a sensor body 25 mounted on the side of the throttle body 24.
and a throttle shaft 26 to which the throttle valve 12 is attached.
rotor arms 27 and 28 that fit into the tips of the rotor arms 27 and 28 and rotate together with the throttle valve 12; brushes 29 and 30 provided at the tips of the rotor arms 27 and 28, respectively; Correspondingly, two tracks of resistors are roughly constructed from a resistor substrate 31 printed with a pattern (not shown). Reference numerals 32, . . . are electrode portions provided at the ends of each resistor, which are respectively connected to terminals 33, .

That is, the throttle valve opening sensor 18 is equipped with two potentiometers each serving as a throttle valve opening detection means, and the first potentiometer constituted by the brush 29 on the outer circumferential side is shown in FIG. The second potentiometer constituted by the inner brush 30 has the characteristics as shown in (If) of FIG. 5. Specifically, the first potentiometer has a detectable throttle valve opening degree of 0 to α.

On the other hand, the change in the sensor output Vs with respect to the change in the throttle valve opening is rapid, and the second potentiometer is limited to a range of 0 when the throttle valve is fully open (α, ).
~α, while the sensor output VR changes slowly with respect to the change in the throttle valve opening. Therefore, in the small opening range within α1, for example in the range from 0 to α, the first potentiometer exhibits higher detection accuracy.

The control device 23 controls the fuel injection amount based on the throttle valve opening detected by the throttle valve opening sensor 18 and the engine speed detected by the crank angle sensor 19. When detecting the opening or opening of the throttle valve, the detection signal v8 from the first potentiometer and the detection signal VFI from the second potentiometer are selectively used as appropriate.

FIG. 6 is a flowchart showing a program for selecting this detection signal, which will be explained below. This program runs every hour.

First, in steps 1 and 2, as shown in FIG.
Read R, and in step 3.4, set the value V read this time.
sn, VRn and the previously read value Vsn-1°Vp
The differences ΔVsn and ΔVnn from n−x are determined, respectively.

The rate of change of each differential signal determined in this way is related to the operation stray current of the throttle valve 12, so if the value is excessively large, it can be determined that it is an abnormal value due to a momentary interruption or the like.

In step 6.7, each change rate △Vsn, △Vy+
By comparing n to a predetermined value and K, the abnormality is determined. That is, in a region where detection by both potentiometers is possible, specifically in a small opening region where the opening detected by the signal Vsn is less than α3 (step 5), if the rate of change △Vsn is less than 1 (step 6). , the detection signal Vsn is determined to be a normal value, and the detection signal Vsn and the rate of change ΔVsn are output as control signals (step 8). Further, in the small opening range less than α1, the rate of change ΔVsn is 75KK+ or more, and the rate of change ΔVan is K.

If it is less than that, normal values VRn and ΔVHn are output (step 10). Therefore, as shown in FIG. 7, even if pulse-like noise occurs in the first potentiometer due to a momentary interruption or the like, it will not affect the fuel injection amount control in any way. Furthermore, the rate of change of both △Vsn, △
If VRn is equal to or greater than , K (this applies to cases where instantaneous interruption occurs in both potentiometers at the same time, etc.), both detection signals Vsn and VRn are abnormal values, so the previously read value Vsn -1 and the previously determined rate of change ΔVsn-+ are output as control signals (step 9). The opening degree detected by the signal Vsn is α9
In the above-mentioned large opening range, since the opening is substantially detected by a single potentiometer, the detection signals VRn and △VRn are always detected by the second potentiometer.
is output as a control (goods) signal (step 5.10)
.

In the above embodiment, a two-track type throttle valve opening sensor 18 with different output characteristics is used, but it goes without saying that the present invention is not limited to this. If the valve opening degree detecting means is capable of detecting the opening degree, it is possible to eliminate abnormal values due to instantaneous interruptions etc. at the full opening degree.

Effects of the Invention As is clear from the above explanation, according to the throttle valve opening detection device according to the present invention, even if an abnormal value is detected by the throttle valve opening detection means consisting of a potentiometer or the like due to a momentary interruption, etc. Since only the signal from the normal throttle valve opening detection means is always selected as the engine control signal, it does not affect the air-fuel ratio control at all and does not cause deterioration of exhaust components or drivability.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram showing the configuration of the present invention, FIG. 2 is a configuration explanatory diagram showing an embodiment of the invention, FIG. 3 is a plan view of the throttle valve opening sensor, and FIG. 4 is a cross-sectional view of the same. , Fig. 5 is an output characteristic diagram of the throttle valve opening sensor, Fig. 6 is a flowchart of the detection signal selection program, and Fig. 7 is a characteristic showing an example of changes in the output signals Vs and VR of the throttle valve opening sensor. It is a diagram. 1. Throttle valve opening detection means, 2.0 abnormality detection means, 3.
Exposure/selection means. 2 people outside

Claims (1)

[Claims] (1) A throttle valve opening detection device that detects the opening of a throttle valve of an internal combustion engine includes a plurality of throttle valve opening detection means that generate signals according to the throttle valve opening, and the throttle valve opening detection means. means for detecting an abnormality in the detecting means from the rate of change of the opening signal generated; and means for selecting a normal signal from the throttle valve opening detecting means as an engine control signal based on the detection of the abnormality. A throttle valve opening detection device featuring: