JPS61118557A - Apparatus for diagnosing electronic type fuel injection device - Google Patents

Abstract

PURPOSE:To enable a plurality of types of injection units to be diagnosed by counting the number of pulses of injection valve opening controlling signal for a predetermined time to judge whether it is of current controlling system or of voltage controlling one and process necessary data on the basis of the result of judgment. CONSTITUTION:A data processing unit 5 receives one drive signal of an injection valve coil 1 through a wave from shaping circuits 2, 3 and the other through an AD converting circuit 4. And first, cylinders are checked and then pulses are checked. When either one of the signals has pulses, the leading portion of the pulse is detected to judge whether or not the pulse width exceeds a predetermined value T1. If the pulse width is larger than T1 and N or more of pulses are present between T1 and T2, whether or not they are in a half or more of total number of cylinders is checked. If they exceeds a half of total number of cylinders, a fuel injection unit is judged to be of current controlling system. Also if less than N pulses, the cylinders are renewed. After the repetition of these operation to complete the renewal of the total cylinders said unit is judged to be of voltage controlling system to process data respectively according to the result of judgment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a diagnostic device for an electronic fuel injection system, and particularly to a diagnostic device suitable for improving versatility.

[Background of the invention]

As a method for diagnosing an electronic fuel injection device of an automobile engine, for example, as shown in Japanese Utility Model Application Publication No. 58-142373, electric signals etc. applied to the fuel injection valve are processed by a data processing device to determine whether the fuel injection device is OK or not. is being diagnosed. However, this method is applicable to a fuel injection device called the so-called rL-Jetro method, and there is a problem in that it cannot be applied to a device called a “current control type” that has been realized over the past few years. In addition, regarding injection time measuring instruments, such as the engine scope ES-900 commercialized by Okuda Koki Co., Ltd. in 1982, the signal waveform projected on the CRT screen is read by the scale on the screen. However, the problem is that it is difficult to obtain accurate values.

FIG. 7 is an overview diagram of a current-controlled fuel injection device, where 21 is the main body of the device, 22 is an injection valve coil, 23 is fuel, and one terminal of the injection valve coil 22 is directly connected to a battery (voltage Vs) 24. Then, the other terminal B is connected to the transistor 26 of the control device 25, and the voltage signal VL is chopper-controlled to drive the fuel injection valve and finally adjust the injection amount of the fuel 23. be.

FIG. 8 is an overview diagram of a voltage-controlled fuel injection device. Similar to FIG. 7, the terminal B of the injector coil 22 is connected to the transistor 26 of the control device 25, but the terminal is connected to the current-limiting resistor 27. The voltage signal VL is connected to the battery 24 through the terminal 24, and the voltage signal VL is pulse-controlled to ultimately adjust the injection amount t of the fuel 23.

The one shown in FIG. 8 has a current limiting resistor 27 between the injection valve coil 22 and the battery 24, so there is a limit in reducing the delay in electrical response time.

Therefore, the current control type shown in FIG. 7 has appeared, but in this case, the current applied to the injection valve coil 22 is chopper controlled.

FIG. 9 is a drive signal waveform diagram of the injection valve coil 22 in FIGS. 7 and 8, and FIG. 9(a) shows that in FIG.
b) shows that of FIG. In the case of FIG. 9(a), the granger of the injection valve is driven to open by the first pulse (approximately 1.2 m%), and thereafter, the valve is held open by limiting electric power to chopper control.

In FIG. 9(b), the injection valve drive signal is one pulse per injection, and the opening and holding of the plunger of the injection valve are controlled by the same pulse.

FIG. 10 is a schematic diagram of a device disclosed in Japanese Patent Application Laid-Open No. 58-142373, in which a signal from a terminal (or B) of an injection valve coil 22 is transferred to a waveform shaping circuit 28, an A-D conversion circuit 29t-
The data is input to the data processing device 30 via the injector waveform, and the data processing device 30 processes data such as injection time and injection timing from the injection valve waveform, and diagnoses whether or not these data are normal. Here, regarding the injection time, the signal from terminal A or B in FIG.
0.1m5ec), and then combine this with a constant potential [for example, (V
m2) volts]. Therefore, if this is applied to FIG. 7, a problem arises in that the first pulse is regarded as the injection time.

Furthermore, there is a problem that the chopper pulse period is faster than the A/D conversion time, which also causes problems when processing other data.

[Purpose of the invention]

The present invention has been made in view of the above, and an object thereof is to provide a diagnostic device for an electronic fuel injection system that is capable of diagnosing a plurality of types of electronic fuel injection systems.

[Summary of the invention]

Injector control in electronic fuel injection systems is classified into two types: voltage control type and current control type, and there are significant differences between the two types. It is designed to obtain results and consists of a waveform shaping circuit that converts the injection valve drive signal into a pulse wave and a data processing device that receives the valve opening control signal from this waveform shaping circuit and processes the data. a counting means for counting the number of pulses of the control signal from a first predetermined time period to a second predetermined time period after the start of the valve opening control signal of the injection valve; and a number of pulses counted by the counting means. The data processing device is equipped with a discriminating means for discriminating whether the electronic fuel injection device is a current control type or a voltage control type, and a processing means for performing necessary data processing based on the discrimination by the discriminating means. It is a feature.

[Embodiments of the invention]

The present invention will be explained in detail below with reference to the embodiments shown in FIGS. 1, 3, 4, and 6, as well as FIGS. 2 and 5.

FIG. 1 is a functional block diagram showing one embodiment of the fuel injection valve drive signal processing device of the diagnostic device of the present invention. In Fig. 1, 1 is an injection valve coil, and terminal A of the injection valve coil 1 (
Alternatively, the drive signal of B) is inputted to the waveform shaping circuits 2 and 3, and the output of the waveform shaping circuit 2 is converted into a digital signal by the A-D conversion circuit 4 and inputted to the data processing device 5.
The output of the waveform shaping circuit 3 is also input to the data processing device 5.

Figure 2 is a waveform diagram of the signal that has passed through the waveform shaping circuit 3 of Figure 1. Figure 2 (a) is for Figure 9 (a), Figure 2 (b) is for Figure 9 (b). It is a matter of the case.

FIG. 3 is a flowchart showing an embodiment for determining the control method of the fuel injection device in the data processing device 5 of FIG. First, after starting, perform a cylinder check in step S1, perform all pulse checks in steps 82 and 83, and if there is a pulse on one side or the other, proceed from step S3 to step S4, find the beginning of the pulse, and check the pulse. Check whether the width is a predetermined value of 11 or more.

If it is T1 or more, check whether there are N or more K pulses between T1 and T2 in step 85. This means that there are vehicles that have only a trigger signal, so in order to exclude those that only have this signal. If there are N or more cylinders, it is checked in step S6 whether or not the number of cylinders exceeds 1/2 of the total number of cylinders.
In step S7, it is determined that the fuel injection device is a current control type, and in step S8, data processing corresponding to the determination is performed. If the number of cylinders is not N or more in step S5 [FIG. 2(b)], the cylinders are updated in step S9, the process returns to step S1, and this process is repeated until all the cylinders are completed. In step S10, the fuel injection device performs voltage control. It is determined that the expression is an expression, and data processing corresponding to the expression is performed in step 811.

According to the embodiment of the present invention described above, for example, in a four-jet, current-controlled type that determines the injection time, the initial pulse width (
Valve opening drive section) t-measurement, and then the width of the chopper part (
It is only necessary to perform a processing procedure of measuring the valve open holding interval), and it can be applied to any method.

Next, a method for measuring the injection time of the current-controlled fuel injection device will be described in detail.

FIG. 4 is a circuit diagram showing an embodiment of a waveform shaping circuit for a drive signal of an injection valve coil. The drive signal 6 for the injection valve coil is divided into voltages by two resistors 7 and 8, and after being clamped to a constant voltage by a Zener diode 9, the injection is performed via an inverter 10 in the case of the current control type of the data processing device 5 shown in FIG. It is configured to be input into a time measuring device 11.

FIG. 5 is a time chart of voltage waveforms at various parts in FIG. 4. FIG. 5(a) shows the drive signal (vL) 12, which is applied to the pace of the transistor 26 of the control device 25 in FIG. That is, first, a voltage is applied for a certain period of time TA to start the plunger, and then chopper control is performed for a period of time T1 to limit the current and keep the plunger open. Under such control, the voltage signal 13 generated at one terminal of the injection valve coil 22 becomes as shown in FIG. 2(b). The control signal 14 in FIG. 5(C) is obtained by processing this voltage signal 13 (corresponding to 6 in FIG. 4) by the waveform shaping circuit in FIG. The open/closed state is shown in FIG. 4(d).

That is, the fuel injection time is determined by processing and calculating by a microcomputer based on the control signal 14.

FIG. 6 is a flowchart showing an example of the processing contents. First, in step 821, the time TA of the plunger control signal 14 is measured. Here, TAd is a constant value (1.2 to 1.5 m5ec) regardless of the vehicle speed.

In other words, the injection time is controlled by making the holding time Tm of the plunger variable. Next, step 822
In consideration of the variation in time TA, a counter that counts every 204 times TA, that is, 1.2 TA, is set to N, and in step S23, the counter N is reset.

In step 824, the low voltage level time ΔT t, ()c) (k is a positive integer) of the plunger control signal is measured every 1.2Tm. Then, in step 825, +1 is added to the counter N every time 1.2 TA. In step 826, it is fully determined whether ΔT L,(k) is larger than the set time ΔT, and if it is smaller, the process returns to step 824, and if it is larger, it is assumed that there is no granger control signal.
Proceeding to step 827, the fuel injection time Tr is calculated using the following equation.

T v = N X 1.2 X TA-ΔT L (
k) ・” = (1) The above allows the fuel injection time of the current-controlled fuel injection device to be accurately measured.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to diagnose a plurality of types of electronic fuel injection devices.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing an embodiment of the fuel injector drive signal processing device of the electronic fuel injection device diagnostic device of the present invention, and FIG. 2 is a waveform diagram of the signal passing through the waveform shaping circuit shown in FIG. M1. , FIG. 3 is a flowchart showing an embodiment for determining the control method of the fuel injection device in the data processing device shown in FIG. 1, and FIG. A circuit diagram showing an example, FIG.
Figure 6 is a 70-chart showing an example of the processing content of the injection time measuring device in Figure G4, Figure 7 is a schematic diagram of the current-controlled fuel injection device, Sa is a schematic diagram of a voltage-controlled fuel injection system, and Fig. 9 is a schematic diagram of a voltage-controlled fuel injection device.
FIG. 8 is a drive signal waveform diagram of an injection valve coil, and FIG. 10 is a schematic diagram of a conventional diagnostic device. l... Injection valve coil, 2.3... Waveform shaping circuit, 4
...A-D conversion circuit, 5...de! ri processing equipment, 7,
8...Resistor, 9...Zena diode, 10...
- Inverter, 11... Injection time measuring device.

Claims (4)

[Claims] 1. A diagnostic device comprising a waveform shaping circuit that converts a fuel injection valve drive signal of an electronic fuel injection device into a pulse wave, and a data processing device that takes in a valve opening control signal from the waveform shaping circuit and processes the data. a counting means for counting the number of pulses of the control signal from a first predetermined time period to a second predetermined time period after the start of the valve opening control signal; The data processing device is characterized in that the data processing device is equipped with a discriminating means for discriminating whether the type fuel injection device is a current control type or a voltage controlled type, and a processing means for performing necessary data processing based on the discrimination by the discriminating means. A diagnostic device for electronic fuel injection systems. 2. The electronic fuel injection system according to claim 1, wherein the counting means is configured to provide a non-opening control signal when the valve opening control signal becomes zero within the first predetermined time period. Equipment diagnostic equipment. 3. The electronic fuel injection system according to claim 1 or 2, wherein the determining means is configured to determine that the electronic fuel injection system is a current control type when the number of pulses counted by the counting means is several or more. Equipment diagnostic equipment. 4. The waveform shaping circuit includes a voltage dividing circuit and a clamp circuit that clamps a signal from the voltage dividing circuit to a constant voltage, and the processing means adjusts the waveform when it is determined that the electronic fuel injection device is a current control type. The electronic device according to claim 1, 2, or 3, which is configured to calculate the fuel injection time by measuring the voltage level time of the valve opening control signal from the shaping circuit at predetermined intervals. Diagnostic device for type fuel injection system.