JP5461380B2 - Pumping unit - Google Patents

Description

  The present invention relates to a pump unit that is controlled so that a discharge pressure becomes a target pressure, and more particularly to abnormality determination of a pressure detection unit that detects the discharge pressure and control in the event of an abnormality.

2. Description of the Related Art Recent fuel injection systems for internal combustion engines include a fuel injection system using a so-called in-cylinder injection system that directly injects higher pressure fuel into a high pressure cylinder.
In the fuel supply device in the in-cylinder injection system, a low-pressure fuel pump and a high-pressure fuel pump are arranged in series, and the fuel in the fuel tank is temporarily controlled at the low-pressure side target pressure by the low-pressure fuel pump. Is controlled to a high-pressure side target pressure by a high-pressure fuel pump disposed at a position close to the injector, and fuel at the high-pressure side target pressure is injected from the injector.
In the conventional fuel supply device, the high pressure fuel pump performs feedback control using the high pressure side pressure sensor so as to achieve the high pressure side target pressure, and the low pressure fuel pump uses the low pressure side pressure sensor so as to achieve the low pressure side target pressure. Feedback control is performed.

For example, in the prior art described in Patent Document 1, fuel in a fuel tank is pumped to a low pressure region by a feed pump, fuel in a low pressure region is pumped to a high pressure region by a high pressure pump, and fuel in the high pressure region is fed. A fuel injection device for an internal combustion engine that injects from an injector is disclosed. A dedicated pressure sensor for detecting the pressure in the low pressure region is provided in the low pressure region, and a dedicated high pressure sensor for detecting the pressure in the high pressure region is provided in the high pressure region. In the low pressure region, the feed pump is controlled based on the pressure detected by the pressure sensor (for the low pressure region), and in the high pressure region, the high pressure pump is controlled based on the pressure detected by the high pressure sensor (for the high pressure region).
Further, for example, in the prior art described in Patent Document 2, the pressure detected by the pressure sensor or the pump motor is not used without using a relatively expensive hydraulic pressure sensor for detecting the supply pressure of the hydraulic pressure source (gear pump). There is disclosed a brake fluid pressure control device for a vehicle that reduces the cost and simplifies the device by controlling the braking force based on the fluid pressure estimated from the rotation speed and the supply current.
Further, for example, in the prior art described in Patent Document 3, the fuel pressure is estimated from the pump rotation speed, the actual fuel pressure detected by the pressure sensor is compared with the estimated fuel pressure, and abnormality of the relief valve of the pump is determined. A fuel supply control device is disclosed.

Special table 2009-540205 gazette JP 2006-175905 A JP 2009-281184 A

In any of Patent Documents 1 to 3, if an abnormality occurs in the pressure sensor, the correct discharge pressure (hydraulic pressure) of the pump cannot be detected, and normal control may not be performed. However, there is no disclosure regarding a method for determining an abnormality of the pressure sensor or a measure when an abnormality occurs in the pressure sensor.
The present invention was devised in view of such points, and an abnormality occurs in the pump unit that can appropriately detect that an abnormality has occurred in the pressure detection means that detects the discharge pressure of the pump, and the pressure detection means. It is an object of the present invention to provide a pump unit that can continue normal control without falling into an uncontrollable state.

In order to solve the above problems, the fuel supply apparatus according to the present invention takes the following means.
The first aspect of the present invention is a pump unit comprising a sensorless brushless motor and a control means for controlling the brushless motor, wherein pressure detecting means is provided on the discharge side of the pump unit. The control means controls the brushless motor so that a detected pressure, which is a pressure detected by the pressure detecting means, becomes a target pressure.
The control means can further detect the amount of current supplied to the brushless motor and the number of rotations of the brushless motor. When the pressure detection means is abnormal, the detected current amount and the detected current amount are detected. Based on the rotational speed, an estimated pressure obtained by estimating the pressure on the discharge side is obtained, and the brushless motor is controlled so that the obtained estimated pressure becomes the target pressure.

According to the first aspect, when an abnormality occurs in the pressure detection means, the discharge pressure is set to the target by using the estimated pressure obtained from the amount of current supplied to the brushless motor and the rotation speed of the brushless motor. Control to be pressure.
The estimated pressure is slightly less accurate than the pressure detected by the pressure detection means, but normal control is continued using the estimated pressure even if the detected pressure cannot be used due to an abnormality in the pressure detection means. be able to.

Next, according to a second aspect of the present invention, there is provided a pump unit comprising a sensorless brushless motor and a control means for controlling the brushless motor, wherein a pressure detection means is provided on the discharge side of the pump unit. The control means controls the brushless motor so that a detected pressure, which is a pressure detected by the pressure detecting means, becomes a target pressure.
Further, the control means can detect the amount of current supplied to the brushless motor and the rotation speed of the brushless motor, and discharge based on the detected current amount and the detected rotation speed. An estimated pressure obtained by estimating the pressure on the side is obtained, and it is determined whether or not the pressure detecting means is abnormal based on the detected pressure and the estimated pressure.

  In the second aspect of the invention, for example, the accuracy of abnormality determination is further improved based on the deviation between the estimated pressure estimated from the rotational speed and current amount of the brushless motor and the detected pressure detected by the pressure detecting means. Can be made. For example, in addition to simple disconnection abnormalities (circuit open) and short circuit abnormalities (circuit shorts), more accurate abnormalities such as whether the output detection signal is close to the signal that should be output originally Judgment can be made.

  Next, a third invention of the present invention is the pump unit according to the second invention, wherein the control means includes a deviation between the target pressure and the detected pressure, and the detected pressure and the estimated pressure. Whether or not the pressure detecting means is abnormal is determined on the basis of the deviation.

  According to the third aspect of the invention, the abnormality of the pressure detecting means is determined based on the deviation between the estimated pressure and the detected pressure, and further the abnormality of the pressure detecting means is determined based on the deviation between the target pressure and the detected pressure. This makes it possible to make a more accurate determination.

It is a figure explaining one Embodiment of the fuel-injection system to which the pump unit 20 of this invention is applied. It is a figure explaining the example of a structure of the pump unit. It is a figure explaining the example of this application and the conventional control block diagram. It is the electric current and rotation speed-pressure characteristic in the low-pressure fuel pump measured in advance. It is a flowchart explaining the example of the process sequence of the low voltage | pressure side control means CL, and the example of the process sequence of the feedback process in the said process sequence. It is a figure explaining the example of the process sequence of the abnormality determination process in the process sequence of the low voltage | pressure side control means CL. It is a figure explaining the other example of the process sequence of an abnormality determination process.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. FIG. 1 is a diagram illustrating an embodiment of a fuel injection system for an internal combustion engine to which a pump unit 20 of the present invention is applied. The pump unit of the present invention is a pump unit provided with a sensorless brushless motor, and corresponds to the pump unit 20 (low pressure fuel pump unit) shown in FIG.

● [Configuration of fuel injection system (Fig. 1)]
The fuel injection system shown in FIG. 1 has a fuel supply device 1 constituted by a pump unit 20 (low pressure fuel pump unit) and a high pressure fuel pump unit 30 of the present invention.
The fuel tank 10 stores fluid fuel.
The pump unit 20 includes a low-pressure fuel pump ML (corresponding to a sensorless brushless motor) and a low-pressure side control means CL (corresponding to a control means).
The low-pressure side control means CL receives a low-pressure side target pressure from a separate external control device 50 (engine control computer or the like), and the discharge pressure of the low-pressure fuel pump ML (pressure in the pipe HL) is equal to the low-pressure side target pressure. The low-pressure fuel pump ML is controlled so that the fuel in the fuel tank 10 is pumped into the pipe HL (corresponding to the low-pressure region).
The low-pressure fuel pump ML is a sensorless brushless motor, and details will be described later.
Note that the pressure detection means 40L is provided in the discharge side pipe HL of the low pressure fuel pump ML, and the low pressure side control means CL is low pressure so that the detected pressure detected by the pressure detection means 40L becomes the low pressure side target pressure. The fuel pump ML is controlled.

The high pressure fuel pump unit 30 includes a high pressure fuel pump MH and a high pressure side control means CH.
The high pressure side control means CH receives a high pressure side target pressure from a separate external control device 50, and the discharge pressure of the high pressure fuel pump MH (pressure in the pipe HH) becomes the high pressure side target pressure. The MH is controlled, and the fuel in the pipe HL (corresponding to the low pressure region) is pumped into the pipe HH (corresponding to the high pressure region).
In addition, the pressure detection means 40H is provided in the discharge side pipe HH of the high pressure fuel pump MH, and the high pressure side control means CH has a high pressure so that the detected pressure detected by the pressure detection means 40H becomes the high pressure side target pressure. The fuel pump MH is controlled.

The injectors 61 to 64 inject high-pressure fuel in the delivery 60 connected to the pipe HH based on a drive signal from the external control device 50.
For example, when the fuel pressure in the delivery 60 greatly exceeds the assumed pressure, it is returned to the pipe HL via the valve 70.
Further, the external control device 50 receives detection signals from various input means (sensors, etc.), outputs control signals for various output means (actuators, etc.), and drives the drive signals of the injectors 61 to 64 and the low pressure side. Outputs the target pressure and high-pressure side target pressure.

● [Configuration of pump unit 20 (FIG. 2)]
As shown in FIG. 2, the low-pressure fuel pump ML is a sensorless brushless motor, and has, for example, three-phase coils of U phase, V phase, and W phase.
The low pressure side control means CL for controlling the brushless motor includes a calculation means 21 such as a CPU, a position detection circuit 22 for detecting the rotational position of the brushless motor, and a drive for outputting a drive current to the U phase, V phase, and W phase. It has a circuit (Tu1-Tw2).
The computing means 21 detects the rotational position of the brushless motor based on the detection signal from the position detection circuit 22 and outputs a drive signal corresponding to the rotational position from the drive circuit (Tu1 to Tw2).
For example, the position detection circuit 22 is a counter electromotive current detection circuit, and a pulse signal is input every time the brushless motor reaches a predetermined rotational position, and the calculation means 21 outputs a drive signal (PWM signal) every time the pulse signal is input. Etc.).
Further, the low pressure side target pressure is inputted from the external control device 50 and the detection signal is inputted from the pressure detecting means 40L to the calculating means 21.

The calculating means 21 can determine the rotation speed of the brushless motor from the interval time of the pulse signal from the position detection circuit 22.
Further, the calculation means 21 calculates the brushless motor from the signal output to the drive circuit (Tu1 to Tw2) (for example, in the case of a PWM signal, the duty of the PWM signal (ratio of ON pulse width to the pulse period [%])). The amount of current supplied to can be obtained.
Thus, in order to control the sensorless brushless motor, the input state from the position detection circuit 22 originally necessary for rotation control and the output state to the drive circuits (Tu1 to Tw2) are used to newly detect a detection circuit or the like. The calculating means 21 can detect the rotation speed and current amount of the brushless motor.

[Control block diagram of the present application (FIG. 3A) and conventional control block diagram (FIG. 3B)]
FIG. 3A shows a control block diagram of the present application for controlling the low-pressure fuel pump ML, and FIG. 3B shows a conventional control block diagram.
[Conventional Control Block Diagram (FIG. 3B)]
As shown in the control block diagram of FIG. 3B, conventionally, the target pressure (in this case, the low-pressure side target pressure) and the detected pressure (actually the low-pressure fuel pump ML detected by the pressure detection means 40L) at the node N1A. And the calculated deviation is input to the calculation block B1.
In the calculation block B1, the control amount is calculated based on the input deviation, and the optimal control amount is calculated for each of the drive circuits (Tu1 to Tw2) based on the rotational position detection signal from the position detection circuit 22, and calculated. The controlled amount is input to the drive block B2 (drive circuit (Tu1 to Tw2)).
The drive block B2 outputs a drive signal to the low-pressure fuel pump ML based on the input control amount.
Then, the discharge pressure of the low-pressure fuel pump ML is detected by the pressure detecting means 40L, and the detected actual pressure (detected pressure) is negatively fed back to the node N1A.

[Control Block Diagram of the Present Application (FIG. 3A)]
As shown in FIG. 3 (A), in the control block diagram of the present application, a calculation block B3 for calculating an estimated pressure, and a switching means for selecting a pressure to be negatively fed back to the node N1, compared to the conventional (FIG. 3 (B)). A calculation block B4 for outputting a switching signal to the SW and switching means SW is added. With this configuration, either (estimated pressure) or (detected pressure) is negatively fed back to the node N1. Hereinafter, differences from the conventional control block diagram (FIG. 3B) will be mainly described.

The calculation block B3 includes a current amount (current amount supplied to the low-pressure fuel pump ML) based on the control amount obtained in the calculation block B1 and a rotation speed (low-pressure fuel based on the detection signal from the position detection circuit 22). The rotational speed of the pump ML) is input. In the calculation block B3, the discharge pressure (estimated pressure) is calculated based on the amount of current and the rotation speed. A method for calculating the estimated pressure will be described later.
The calculation block B4 receives the estimated pressure calculated in the calculation block B3, the detected pressure detected by the pressure detection means 40L, and the target pressure (low pressure side target pressure) input to the node N1. Then, it is determined whether or not an abnormality has occurred in the pressure detection means 40L. If the calculation block B4 determines that no abnormality has occurred in the pressure detection means 40L, the switching means SW is set to the (detection pressure) side, and the (detection pressure) is negatively fed back to the node N1, so that the pressure detection means When it is determined that an abnormality has occurred in 40L, the switching means SW is set to the (estimated pressure) side, and (estimated pressure) is negatively fed back to the node N1.
The processing of the calculation block B4 (processing for determining an abnormality of the pressure detection means 40L) will be described later.

● [Method for obtaining pressure from current and rotational speed (Fig. 4)]
Next, a method for obtaining the estimated pressure from the current amount and the rotational speed (processing of the calculation block B3 in FIG. 3A) will be described with reference to FIG.
The characteristic graph shown in FIG. 4 is a characteristic graph of the low-pressure fuel pump ML, and the relationship between the current [A] and the rotational speed [rpm] when the discharge pressure is A1 [KPa] is indicated by the first dotted line. The relationship between the current [A] and the rotation speed [rpm] when the pressure is A2 [KPa] is shown by the second dotted line, and the relationship between the current [A] and the rotation speed [rpm] when the discharge pressure is A3 [KPa]. Is indicated by a solid line, the relationship between the current [A] at a discharge pressure of A4 [KPa] and the rotational speed [rpm] is indicated by a one-dot chain line, and the current [A] at a discharge pressure of A5 [KPa] The relationship of the rotational speed [rpm] is shown by a two-dot chain line. Note that A1 <A2 <A3 <A4 <A5.

The pressure (discharge pressure) is higher when the current is larger (the load is higher) even at the same speed, and the pressure (discharge pressure) is higher when the speed is lower (the load is higher) even at the same current. Become.
The calculating means 21 stores the low-pressure fuel pump characteristics shown in FIG. 4 and can determine the pressure from the detected current amount and the rotational speed as follows. For example, if the detected (current amount [A], rotation speed [rpm]) is (C1 [A], R1 [rpm]), as shown in the example of FIG. By interpolating between the point P (A2) on the basis A2 [KPa] and the point P (A3) on A3 [KPa], the pressure of (C1, R1) can be obtained.
As described above, when the rotation speed is known but the load (current) of the brushless motor is not known, it is difficult to estimate the discharge pressure more accurately, and the current (load) is known but the rotation speed (flow rate) is not known. Even in this case, it is difficult to estimate the discharge pressure more accurately. In the present application, a more accurate discharge pressure of the brushless motor can be estimated from the rotation speed (flow rate) and current (load).

[Example of processing procedure of low-pressure side control means CL (FIG. 5A) and processing procedure of feedback processing in the processing procedure (FIG. 5B)]
Next, an example of the processing procedure of the low-pressure side control means CL (calculation means 21) will be described with reference to FIG.
The low-pressure side control means CL starts the processing shown in FIG. 5A at a predetermined timing such as every predetermined time interval or every time a detection signal from the position detection circuit 22 is inputted.

In step S10, the low pressure side control means CL takes in the target pressure (in this case, the low pressure side target pressure) from the external control device 50, and proceeds to step S11.
In step S11, the low-pressure side control means CL acquires the detection signal of the pressure detection means 40L, acquires the detection pressure based on the detection signal (converts the detection signal into the detection pressure), and proceeds to step S12.
In step S12, the low-pressure side control means CL obtains the current rotation speed of the low-pressure fuel pump ML from the interval (cycle) of the pulse signal from the position detection circuit 22. Further, the current amount is obtained based on the drive signal output to the drive circuit (Tu1 to Tw2). And based on the detection signal from the voltage detection means which detects the voltage of the power supply used with the fuel supply apparatus 1, the measurement voltage which is the voltage of the power supply is obtained, and based on the preset reference voltage and the measurement voltage, Correct the amount of current. For example, when the low-pressure fuel pump characteristic shown in FIG. 4 is a characteristic measured on the basis of 12V, the reference voltage is 12 [V]. For example, when the measured voltage is 10 [V], the current amount is corrected as follows.
Current amount (after correction) = Current amount (before correction) * (12 [V] / 10 [V])
Then, an estimated pressure is obtained based on the obtained rotational speed, the corrected current amount, and the low-pressure fuel pump characteristic shown in FIG. 4, and the process proceeds to step S20.
The process of step S12 corresponds to the process of the operation block B3 shown in FIG.
Note that the correction of the current amount by the measurement voltage may be omitted.

In step S20, the low pressure side control means CL determines whether or not an abnormality has occurred in the pressure detection means 40L, and proceeds to step S30.
In step S30, the low-pressure side control means CL performs feedback control on the low-pressure fuel pump ML so that the discharge pressure of the low-pressure fuel pump ML becomes the low-pressure side target pressure, and ends the process.

Next, the feedback process in step S30 in the flowchart of FIG. 5A will be described with reference to FIG. Note that the processing in step S30 corresponds to the processing by the switching means SW, the node N1, the arithmetic block B1, and the driving block B2 in FIG.
In step S31, the low pressure side control means CL determines whether or not the pressure detection means 40L is normal (determined in step S20). When it determines with it being normal (Yes), it progresses to step S32, and when it determines with it being abnormal (No), it progresses to step S33.
When the process proceeds to step S32, the low-pressure side control means CL obtains a deviation between the target pressure taken in step S10 (low-pressure side target pressure) and the detected pressure obtained in step S11, and the low-pressure side control means CL The control amount of the fuel pump ML is calculated, and the process proceeds to step S34.
When the process proceeds to step S33, the low pressure side control means CL obtains a deviation between the target pressure taken in step S10 (low pressure side target pressure) and the estimated pressure calculated in step S12, and based on the deviation, the low pressure side The control amount of the fuel pump ML is calculated, and the process proceeds to step S34.
In step S34, the low-pressure side control means CL drives the drive circuit (Tu1 to Tw2) based on the calculated control amount and the rotational position detection signal detected in step S12 to drive the low-pressure fuel pump ML, and performs processing. finish.

[Processing procedure for determining abnormality of pressure detecting means 40L (FIG. 6)]
Next, the abnormality determination process in step S20 in the flowchart of FIG. 5A will be described with reference to FIG. Note that the processing in step S20 corresponds to the processing by the arithmetic block B4 in FIG.
In step S21, the low-pressure side control means CL takes in the detection signal of the pressure detection means 40L, and determines whether or not the detection signal (detection voltage) exceeds the upper limit threshold value. In the example of the present embodiment, the detection voltage is input as an analog voltage of 0 [V] to 5 [V] corresponding to the pressure, and 4.5 [V], which is not normally possible, is set as the upper threshold. ing. If the upper limit threshold is exceeded (Yes), the process proceeds to step S21T. If the upper limit threshold is not exceeded (No), the process proceeds to step S22.
When the process proceeds to step S21T, the low-pressure side control means CL proceeds to step S21X when the state in which the upper limit threshold is exceeded continues for the first predetermined time (Yes), and does not continue for the first predetermined time (No). Ends the process.
When the process proceeds to step S21X, the low-pressure side control means CL determines that the pressure detection means 40L is abnormal and ends the process (in this case, determines that the disconnection is abnormal).

When the process proceeds to step S22, the low pressure side control means CL determines whether or not the detection signal (detection voltage) of the pressure detection means 40L is below the lower limit threshold value. In the example of the present embodiment, the detection voltage is input as an analog voltage of 0 [V] to 5 [V] corresponding to the pressure, and 0.5 [V], which is not normally possible, is set as the lower limit threshold. ing. If it is below the lower threshold (Yes), the process proceeds to step S22T, and if it is not below the lower threshold (No), the process proceeds to step S23.
When the process proceeds to step S22T, the low-pressure side control means CL proceeds to step S22X when the state of being below the lower limit threshold continues for the second predetermined time (Yes), and does not continue for the second predetermined time (No). Ends the process.
When the process proceeds to step S22X, the low pressure side control means CL determines that the pressure detection means 40L is abnormal and ends the process (in this case, it is determined that the short circuit is abnormal).

When the process proceeds to step S23, the low pressure side control means CL determines that the deviation between the target pressure (in this case, the low pressure side target pressure) and the detected pressure (pressure detected by the pressure detection means 40L) is the first pressure difference (for example, 50 [KPa]) or not is determined. If it is greater than or equal to the first pressure difference (Yes), the process proceeds to step S23A, and if it is less than the first pressure difference (No), the process proceeds to step S25T.
When the process proceeds to step S23A, the low-pressure side control means CL determines whether or not the deviation between the detected pressure and the estimated pressure (pressure estimated from the rotation speed and the current amount) is equal to or greater than a second pressure difference (for example, 30 [KPa]). Determine. If it is greater than or equal to the second pressure difference (Yes), the process proceeds to step S23T, and if it is less than the second pressure difference (No), the process proceeds to step S24.
When the process proceeds to step S23T (Yes), it is determined whether or not this state (the first pressure difference or more in step S23 and the second pressure difference or more in step S23A) continues for a third predetermined time. When it continues for the third predetermined time (Yes), the process proceeds to step S23X, and when it does not continue for the third predetermined time (No), the process ends.
When the process proceeds to step S23X, the low pressure side control means CL determines that the pressure detection means 40L is abnormal, and ends the process. In this case, although the level of the detection signal is within the range between the upper limit threshold and the lower limit threshold, it is determined that the detection signal corresponding to the pressure is not abnormal (indefinite abnormality or characteristic abnormality).

When the process proceeds to step S24, the low-pressure side control means CL determines whether or not the maximum current is being supplied. For example, it is determined whether the duty of the PWM signal is 100 [%] (maximum duty). When the maximum current is being supplied (Yes), the process proceeds to step S24T, and when the maximum current is not being supplied (No), the process proceeds to step S25T.
When the process proceeds to step S24T (Yes), it is determined whether or not this state (supplying the maximum current) continues for a fourth predetermined time. If it has continued for the fourth predetermined time (Yes), the process proceeds to step S24X, and if it has not continued for the fourth predetermined time (No), the process ends.
When the process proceeds to step S24X, the low-pressure side control means CL determines that the system (piping etc.) of the fuel supply device 1 is abnormal and ends the processing (in this case, the pressure detecting means 40L is not abnormal but a pipe leak Etc.).

When the process proceeds to step S25T, the low pressure side control means CL determines whether or not the state (that is, a state in which no abnormality is found) flowing in the determination of step S25 continues for the fifth predetermined time. If it has continued for the fifth predetermined time (Yes), the process proceeds to step S25X, and if it has not continued for the fifth predetermined time (No), the process ends.
When the process proceeds to step S25X, the low pressure side control means CL determines that the pressure detection means 40L is normal (no abnormality is found) and ends the process.

[Another example of processing procedure for determining abnormality of pressure detection means 40L (FIG. 7)]
Next, another example of the abnormality determination processing procedure shown in the flowchart of FIG. 6 will be described with reference to FIG.
The flowchart shown in FIG. 7 is different from the flowchart shown in FIG. 6 in that the process of step S20A (first step) is added and that steps S23, S23A, S24, S24T, and S24X are omitted. Different. Hereinafter, differences from the flowchart shown in FIG. 6 will be mainly described.

In step S20A, the low pressure side control means CL determines whether or not the deviation between the target pressure (in this case, the low pressure side target pressure) and the estimated pressure is greater than or equal to the first pressure difference (for example, 50 [KPa]). When the difference is equal to or greater than the first pressure difference (Yes), the process proceeds to step S21. When the difference is less than the first pressure difference (No), the process proceeds to step S25T.
When the process proceeds to step S21, the low pressure side control means CL determines whether or not the detection signal (detection voltage) exceeds the upper limit threshold value. If the upper limit threshold is exceeded (Yes), the process proceeds to step S21T. If the upper limit threshold is not exceeded (No), the process proceeds to step S22.
When the process proceeds to step S22, the low-pressure side control means CL determines whether or not the detection signal (detection voltage) is below the lower limit threshold value. If it is below the lower threshold (Yes), the process proceeds to step S22T, and if it is not below the lower threshold (No), the process proceeds to step S23T.
The processing of other steps is the same as the processing described with reference to FIG.
As described above, in the process of the flowchart shown in FIG. 7, the process of the flowchart shown in FIG. 6 is simplified, and the determination of the system abnormality (step S24X) is omitted.

As described above, in the pump unit 20 described in the present embodiment, whether or not an abnormality has occurred in the pressure detection means 40L can be determined with higher accuracy without providing a new pressure detection means. Therefore, the system can be simplified and the cost can be reduced.
Further, when it is determined that an abnormality has occurred in the pressure detection means 40L, the low-pressure fuel pump ML is controlled using the estimated pressure, so that the control can be continued more safely without causing control failure. .

The pump unit 20 of the present invention is not limited to the appearance, configuration, circuit, processing, and the like described in the present embodiment, and various modifications, additions, and deletions are possible without departing from the spirit of the present invention. For example, the characteristics of the low-pressure fuel pump ML are not limited to those shown in FIG. 4, and the low-pressure side control means CL and the low-pressure fuel pump ML are not limited to the configuration example shown in FIG.
The pump unit 20 described in the present embodiment is not limited to the fuel pump of the internal combustion engine, and can be applied to various pump units using a sensorless brushless motor.

DESCRIPTION OF SYMBOLS 1 Fuel supply apparatus 10 Fuel tank 20 Pump unit 21 Calculation means (CPU)
22 position detection circuit 30 high pressure fuel pump unit 40L, 40H pressure detection means 50 external control device 61-64 injector CH high pressure side control means CL low pressure side control means (control means)
HH piping (high pressure area)
HL piping (low pressure area)
MH high pressure fuel pump ML low pressure fuel pump (sensorless brushless motor)
Tu1-Tw2 drive circuit

Claims (3)

A sensorless brushless motor,
In a pump unit comprising a control means for controlling the brushless motor,
Pressure detection means is provided on the discharge side of the pump unit,
The control means includes
Controlling the brushless motor so that the detected pressure, which is the pressure detected by the pressure detecting means, becomes the target pressure;
Furthermore, the amount of current supplied to the brushless motor and the number of rotations of the brushless motor can be detected,
When the pressure detecting means is abnormal, an estimated pressure obtained by estimating the pressure on the discharge side based on the detected current amount and the detected rotation speed is obtained,
Controlling the brushless motor so that the obtained estimated pressure becomes the target pressure;
Pumping unit. A sensorless brushless motor,
In a pump unit comprising a control means for controlling the brushless motor,
Pressure detection means is provided on the discharge side of the pump unit,
The control means includes
Controlling the brushless motor so that the detected pressure, which is the pressure detected by the pressure detecting means, becomes the target pressure;
Furthermore, the amount of current supplied to the brushless motor and the number of rotations of the brushless motor can be detected,
Obtain an estimated pressure that estimates the pressure on the discharge side based on the detected current amount and the detected rotation speed,
Determining whether or not the pressure detecting means is abnormal based on the detected pressure and the estimated pressure;
Pumping unit. The pump unit according to claim 2,
The control means includes
Determining whether or not the pressure detecting means is abnormal based on a deviation between the target pressure and the detected pressure and a deviation between the detected pressure and the estimated pressure;
Pumping unit.

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