JPH0551795B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a fuel pump used in automobiles, etc., which monitors abnormal conditions due to overcurrent or wire breakage, and self-diagnoses these abnormal conditions. This invention relates to a self-diagnosis device.

[Conventional technology]

2. Description of the Related Art Conventionally, a roller vane fuel pump has been used as a fuel pump for automobiles, which has an eccentric rotor rotatably provided within a casing, and a plurality of rollers that are retractable and retractable from the outer peripheral surface of the eccentric rotor. This roller vane type fuel pump is designed to prevent damage to the coil due to excessive current flowing through the motor, and to detect disconnections in the harness that supplies power, the coil wound around the armature, etc. A self-diagnosis device as shown in FIG. 5 is attached to the machine.

Therefore, a fuel pump self-diagnosis device according to the prior art will be explained based on FIG. 5.

In the figure, 1 is a conventionally used roller vane type fuel pump, and the fuel pump 1 includes a motor section 1A that is rotated by a DC power source 2, and is rotationally driven by the motor section 1A, and directs fuel toward an injector. It consists of a pump section 1B that discharges water. The motor section 1A is located between the DC power supply 2 and the ground, and is connected in series with a voltage control circuit 3 having a Darlint connection and a resistor 4 for detecting current. The change can be derived as a change in the voltage V ₁ across the resistor 4. Reference numeral 5 denotes a motor control device provided between an arithmetic device 11 and a voltage control circuit 3, which will be described later.
Voltage control circuit 3 based on the voltage control signal from 1
The drive voltage of the motor section 1A is controlled by making the current value of the motor variable.

6 and 7 are voltage dividing resistors provided in series between the DC power supply 2 and the ground, and are set to derive the voltage V ₂ as 0.6V at the high voltage side connection point a of the voltage dividing resistor 6; At the high voltage side connection point b of the piezoresistor 7, the voltage
It is set to derive V ₃ as 0.1V.
Further, 8 indicates an overcurrent detector, and 9 indicates a disconnection detector. The non-inverting input terminal of the overcurrent detector 8 is applied with voltage V ₁ from the current detection resistor 4, and the inverting input terminal is connected. It is connected so that voltage V ₂ is applied from point a, and when voltage V ₁ becomes larger than V ₂ , it outputs an overcurrent detection signal to arithmetic unit 11 via OR circuit 10 . Furthermore, the non-inverting input terminal of the disconnection detector 9 receives a voltage V ₃ from the connection point b.
is applied, and at the same time, a voltage V ₁ from the current detection resistor 4 is applied to the inverting input terminal, and this voltage V ₁
When the voltage drops below V ₃ , a disconnection detection signal is outputted via the OR circuit 10 .

Further, numeral 11 is a calculation device constituted by, for example, a microcomputer, and the calculation device 11
has a first function of outputting a voltage control signal to the motor control device 5 according to a predetermined arithmetic expression, and an OR circuit 10.
It has a second function of outputting an abnormality signal to an alarm 12 such as a lamp or a buzzer provided in the driver's seat of the automobile when an overcurrent detection signal or a disconnection detection signal is input from the driver's seat.

The operation of the fuel pump self-diagnosis device configured as described above will be described.

First, when the current flowing through the motor section 1A of the fuel pump 1 becomes high and an overcurrent state occurs, the voltage _V1 across the current detection resistor 4 also becomes high.
When the voltage V ₁ becomes equal to or higher than the set voltage V ₂ of the overcurrent detector 8 , an overcurrent detection signal is output from the overcurrent detector 8 to the arithmetic unit 11 .

On the other hand, the current flowing through the motor section 1A decreases, resulting in a disconnection state, and the voltage V ₁ across the current detection resistor 4 decreases.
falls below the set voltage _V3 of the disconnection detector 9,
A disconnection detection signal is output from the disconnection detector 9 to the arithmetic unit 11 .

Thus, in response to the input of the overcurrent detection signal or the disconnection signal, the arithmetic unit 11 outputs an abnormality signal to the alarm 12 to notify the abnormality of the fuel pump 1, and outputs a motor stop signal to the motor control device 5 as necessary. . In this manner, the state of the fuel pump 1 can be monitored and self-diagnosis can be performed appropriately when an abnormality occurs.

[Problem that the invention seeks to solve]

Conventionally, roller vane fuel pumps have been widely used as the fuel pump 1, but in recent years, turbine fuel pumps, which are non-displacement pumps, have been developed in order to discharge fuel at higher pressure and with less pulsation. It has become like that.

Here, when comparing the characteristics of the roller vane type fuel pump and the turbine type fuel pump in Figure 6, the rotation speed increases from 2500 rpm to 4300 rpm, and the motor current flowing through the motor section increases to 4.0 A.
The winding resistance of the coil wound around the armature of the motor has increased from 20 _nΩ to 6.5A.
It has increased to 30 _nΩ .

Now, in the case of the roller vane type fuel pump applied to the self-diagnosis device shown in Fig. 5, the motor current is
Since the rated current is 4A, the overcurrent detector 8 that constitutes this self-diagnosis device detects the corresponding set voltage V ₂ (=0.6V) when the current is higher than the rated current by a predetermined minute current. It is set to output an overcurrent detection signal.

On the other hand, in the case of a turbine-type fuel pump, the rated current is when the motor current is 6.5V, so the voltage V of the current detection resistor 4 is naturally 0.6V.
be higher than As a result, when a turbine type fuel pump is installed in place of the roller vane type fuel pump 1 and an attempt is made to detect an overcurrent state of the turbine type fuel pump using the conventionally used overcurrent detector 8, the motor Even though the current is rated at 6.5A, it always operates in an overcurrent state.

As described above, the conventional self-diagnosis device shown in Fig. 5 cannot be immediately applied to turbine-type fuel pumps, and it is thought that roller vane-type and turbine-type fuel pumps will be used together in the future depending on the type of automobile. However, there is a problem in that a separate self-diagnosis device must be manufactured for each type of fuel pump.

The present invention has been made in view of the problems of the prior art, and provides a fuel pump that can be applied to multiple types of fuel pumps by automatically changing self-diagnosis criteria according to the type of fuel pump. The purpose of this invention is to provide a self-diagnosis device.

[Means for solving problems]

In order to solve the above-mentioned problems, a self-diagnosis device according to the present invention is provided with a plurality of pump parts each consisting of a motor part and a pump part which is rotationally driven by the motor part and discharges fuel, as shown in the functional block diagram of FIG. fuel pumps A and B of the following types, and a type determination means for determining the type of fuel pump A that is actually used based on the characteristics of each of the types of fuel pumps A and B;
Judgment value setting means for setting an overcurrent judgment value and a disconnection judgment value for the fuel pump A as two voltage values based on the type result obtained by the type discrimination means, and a judgment value setting means connected in series with the fuel pump A actually used , a resistance means for detecting the current flowing through the fuel pump A as a voltage, and a voltage value at both ends of the resistance means and each set voltage value set by the judgment value setting means are compared to determine whether the fuel pump A is in an overcurrent state or not. The present invention is comprised of an abnormality detection means for detecting two types of abnormalities, including a disconnection state.

In this case, the characteristics of the fuel pumps A and B are preferably any one of rotation speed, motor current, and motor winding resistance, or a combination thereof.

[Effect]

Of the various types of fuel pumps A and B, when the fuel pump A that is actually used is connected to a power source in series with the resistance means, the type discrimination means determines the characteristics that this fuel pump A has, such as the number of revolutions, motor current, motor The type is determined from characteristic values such as winding resistance, and the determination value setting means automatically sets an overcurrent determination value and a disconnection determination value unique to the fuel pump A as a voltage value based on the determination result as a self-diagnosis standard. Thus, the abnormality detection means monitors the voltage value input from the resistance means based on this self-diagnosis standard, and detects overcurrent or wire breakage.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 2 to 4.

Note that in FIG. 2, the same components as in FIG. The difference is that the voltage V ₁ from the current detection resistor 4 is directly input to the arithmetic unit 23, and the voltage V 1 from the current detection resistor 4 is not provided.

However, in this embodiment, a conventionally used roller vane type fuel pump 1 or a recently developed turbine type fuel pump 1' is interchangeably provided in series with the voltage control circuit 3 and the current detection resistor 4. It is something.

A pump rotation sensor 21 detects the rotation speed of the fuel pumps 1, 1', and a search coil is used as the rotation sensor 21, for example.
22 is the motor part 1A, 1 of the fuel pump 1, 1'
A motor drive voltage detector detects the motor drive voltage that drives A', and detection signals from the rotation sensor 21 and the motor drive voltage detector 22 are input to an arithmetic unit 23, which will be described later. Furthermore, since the number of turns of the coil wound around the armature is different between the roller vane type fuel pump 1 and the turbine type fuel pump 1', the motor winding resistance is also different as shown in the characteristic values shown in Fig. 6. However, depending on the magnitude of the voltage detected by the motor drive voltage detector 22, the magnitude of the motor winding resistance can be determined.

Furthermore, 23 is an arithmetic unit used in this example,
The arithmetic unit 23 is composed of a microcomputer including a processing circuit (CPU), a storage circuit (RAM and ROM), etc. The storage circuit such as the ROM contains programs and determination operations shown in FIGS. 3 and 4. The required values (resistance R ₀ , rotation speed M ₀ , current I ₀ ),
Numerical values required for setting operation (judgment voltage V _t , V _r , υ _t ,
υ _r ) etc. are stored. The arithmetic device 23 has a first function of outputting a voltage control signal and a second function of operating the alarm 12, similar to the arithmetic device 11 according to the prior art.

The circuit configuration used in this embodiment is as described above. Next, referring to FIG. 3, the operation of the format determining means and the determination value setting process by the arithmetic unit 23 will be described.

First, the arithmetic unit 23 reads the voltage applied to the DC power supply 2 (step 1), reads the motor drive voltage from the motor drive voltage detector 22 (step 2),
The pump rotation speed is read from the pump rotation sensor 21 (step 3), and the voltage V ₁ across it is read from the current detection resistor 4 (step 4).

Next, the arithmetic unit 23 determines the type of fuel pump actually used in steps 5-7.

That is, as a first determination procedure, it is determined in step 5 whether the motor winding resistance of the fuel pump is greater than or equal to a predetermined resistance R ₀ stored in advance in a ROM or the like, for example, greater than or equal to 25 _nΩ . Regarding this judgment result,
It can be determined directly or indirectly by the magnitude of the motor drive voltage input from the motor drive voltage detector 22. If "YES", proceed to the next step 6.
If the answer is “NO”, proceed to step 10.

As a second determination procedure, in step 6, if the pump rotation speed from the pump rotation sensor 21 is M ₀ or more,
For example, it is determined whether the rpm is 3500 rpm or more, and if ``YES'', the process goes to the next step 7, and if ``NO'', the process goes to step 7.
Move to 10.

Furthermore, as a third determination procedure, step 7 determines that the current flowing through the motor section is greater than or equal to _I0 , e.g.
Determine whether it is 5.5A or more. This determination process can be determined directly or indirectly based on the magnitude of the voltage V ₁ across the current detection resistor 4 . Then, the judgment result of step 7 is “YES”.
If so, it can be determined that the fuel pump actually used is the turbine type fuel pump 1', and if all of steps 5 to 7 are "NO", it is the roller vane type fuel pump 1.

Thus, steps 5 to 7 according to this embodiment are
This is a specific example of the pump type determining means according to the present invention. Note that the step discriminating means according to the present invention does not need to include all of the steps 5 to 7 described above, and may use any one of these steps, or may include any one of these steps in combination. may be configured.

Next, the determination value setting process by the arithmetic unit 23 will be described. First, when it is determined in step 7 that the fuel pump is a turbine type fuel pump, in step 8, the overcurrent determination voltage V _t corresponding to the motor current of 6.5A is determined as follows.
For example, set it as 0.8V in a storage area such as ROM, and in the next step 9 set the disconnection judgment voltage υ _t , for example.
Set as 0.1V.

Furthermore, when it is determined in steps 5 to 7 that the fuel pump is a roller vane type fuel pump, in step 10 the overcurrent judgment voltage _Vr for a motor current of 4.0A is set in the memory area as, for example, 0.6V, and in the next step 11, a disconnection is detected. The determination voltage υ _r is set to, for example, 0.1V.

In this way, if the overcurrent judgment voltage V _t or V _r and the disconnection judgment voltage υ _t , υ _r are set, these set values are fixed self-diagnosis standards for the fuel pump installed in a certain automobile, This value will not be changed thereafter, and the process ends at step 12. Thus, steps 8 to 11 according to this embodiment are specific examples of the judgment value setting means according to the present invention.

Now, once the type of fuel pump to be actually used has been determined and the judgment value setting process has been performed as described above, overcurrent detection and disconnection detection are performed as a routine through the abnormality detection process shown in FIG. .

That is, when the arithmetic unit 23 reads the voltage V ₁ across the current detection resistor 4 (step 21), it reads the overcurrent judgment voltage V _t (V _r ) in the storage area, and the voltage V _{1 is set to the judgment voltage V 1} . It is determined whether or not it is equal to or higher than _r (V _r ) (step 22), and if "YES", an overcurrent alarm signal is output to the alarm 12, and a motor stop signal is output to the motor control device 5 as necessary. On the other hand, if the determination in step 22 is "NO", the process moves to step 24.
It is determined whether the voltage V ₁ is lower than the disconnection determination voltage υ _t (υ _r ), and if "YES", a disconnection notification signal is output to the alarm 12, and a motor stop signal is sent to the motor control device 5 as necessary. Output. If the determination in step 24 is "NO", the process returns to step 21 and monitors abnormalities due to overcurrent or disconnection according to a predetermined program cycle.

Thus, steps 21 to 25 according to FIG. 4 constitute a specific example of the abnormality detection means according to the present invention.

In addition, in the embodiment of the present invention, as a fuel pump,
Although roller vane type and turbine type fuel pumps are illustrated, it is needless to say that the present invention is not limited to these types.

In addition, in the embodiment, the type determination means, the judgment value setting means, and the abnormality detector means are described as being realized by the programs shown in FIGS. 3 and 4. It may also be realized by a hard circuit.

〔Effect of the invention〕

As described in detail above, according to the fuel pump self-diagnosis device according to the present invention, the type of fuel pump is determined from the characteristics of the fuel pump actually used, and the overcurrent judgment value is set according to the type. Since the disconnection judgment value is automatically set and the configuration is configured to use these as self-diagnosis standards, it can be automatically set based on the applicable overcurrent judgment value and disconnection judgment value for any type of fuel pump. It is possible to perform self-diagnosis of abnormal conditions, and not only is manufacturing easy, but also erroneous diagnosis can be reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram showing the basic configuration of a self-diagnosis device for a fuel pump according to the present invention, FIGS. 2 to 4 relate to embodiments of the present invention, and FIG. FIG. 3 is a flowchart showing format discrimination processing and judgment value setting processing; FIG. 4 is a flowchart showing abnormality detection processing; FIGS. 5 and 6 are related to the prior art; FIG. 5 is a circuit configuration diagram showing a self-diagnosis device for a fuel pump according to the prior art, and FIG. 6 is a comparison diagram comparing the characteristics of a roller vane type fuel pump and a turbine type fuel pump. 1...Roller vane type fuel pump, 1'...Turbine type fuel pump, 1A, 1A'...Motor part,
1B, 1B'...Pump section, 3...Voltage control circuit,
4... Current detection resistor, 5... Motor control device,
12... Alarm, 21... Pump rotation sensor, 2
2...Motor drive voltage detector, 23...Arithmetic device.

Claims (1)

[Claims] 1. A plurality of types of fuel pumps consisting of a motor section and a pump section that is rotationally driven by the motor section and discharges fuel, and an actual fuel pump based on the characteristics of each type of fuel pump. Type determination means for determining the type of fuel pump used; Judgment value setting means for setting an overcurrent determination value and a disconnection determination value regarding the fuel pump as two voltage values based on the determination result by the type determination means. , a resistance means that is connected in series with the fuel pump actually used and detects the current flowing through the fuel pump as a voltage, and a voltage value across the resistance means is compared with each set voltage value by the judgment value setting means. A self-diagnosis device for a fuel pump comprising an abnormality detection means for detecting two types of abnormalities of the fuel pump: an overcurrent state and a disconnection state. 2. The fuel pump self-diagnosis device according to claim 1, wherein the characteristic of the fuel pump is any one of rotation speed, motor current, motor winding resistance, or a combination thereof.