JP2012172634A - Leakage inspection device, and leakage inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leakage inspection device and leakage inspection method which allow leakage inspection of a high pressure system in a fuel injection device to be quantitatively executed.SOLUTION: The leakage inspection device 10 inspects the leakage of a high pressure system HPL of a fuel injection device 100. The fuel injection device 100 includes a supply pump 20, a common rail 30, an injector 40, a pressure sensor 51 for detecting pressure of a fuel pressure-accumulated in the common rail 30, and an ECU 50 for controlling fuel injection of the fuel injection device 100. The leakage inspection device 10 includes an inspection controller which pressure-accumulates the fuel in the common rail 30 by a supply pump 20 until reaching a prescribed pressure P1 by controlling the fuel injection device 100 through the ECU 50 and which determines that no leakage occurs in the high pressure system HPL of the fuel injection device 100 when common rail pressure P detected by the pressure sensor 51 is constant during prescribed time T1 under a state of stoppage of the injector 40.

Description

  The present invention relates to a leakage inspection device and a leakage inspection method technology for inspecting leakage of a high-pressure system of a fuel injection device.

  A fuel injection device is a device that injects fuel directly into a combustion chamber of an engine. For example, in a diesel engine, a common rail fuel injection device is used. A common rail type fuel injection device is a device that accumulates fuel boosted by a supply pump in a common rail, distributes fuel accumulated in the common rail to each injector, and controls the injection amount and injection timing by the injector to perform fuel injection. . For example, Patent Document 1 discloses a common rail fuel injection device.

  In the common rail fuel injection device, the pressure of the fuel is increased to a maximum of about 160 MPa by a supply pump. In the common rail fuel injection device, a device or piping through which high pressure fuel boosted by a supply pump passes is defined as a high pressure system of the common rail fuel injection device. Specifically, the path from the supply pump to the injector via the common rail is the high-pressure system of the common rail fuel injection device.

  After the product is assembled as a common rail type fuel injection device, a leak test is performed to check whether there is a leak in each assembled part. Usually, the leak inspection is performed by enclosing air or nitrogen gas inside the apparatus or piping instead of fuel. However, in the high-pressure system of the common rail type fuel injection device, when the supply pump is driven in a state where fuel is not supplied, the seizure of the pump occurs. Moreover, it is practically difficult to increase the pressure of air or nitrogen to 160 MPa.

  At present, after the product is assembled as a common rail type fuel injection device, only a low pressure system such as a fuel escape pipe from the common rail and the injector can be inspected for leakage. In the low pressure system of the common rail fuel injection device, air or nitrogen gas is sealed inside the device or piping to perform an air leak inspection. The air leak test is a quantitative leak test in which air or nitrogen gas is sealed in a device or pipe to be inspected to obtain a predetermined pressure, and whether there is a leak is determined by a change in the predetermined pressure after a predetermined time has elapsed. .

  On the other hand, after the product is assembled as a common rail fuel injection device, the high-pressure system has not been inspected for leakage. In the high-pressure system of the common rail fuel injection device, when the diesel engine is test-started, the fuel is boosted to a maximum of about 160 MPa by a supply pump, and a visual leak inspection is only performed. That is, in the high-pressure system of the common rail fuel injection device, quantitative leak inspection is not performed, and it cannot be said that sufficient quality assurance is provided for fuel leakage.

JP 2010-216383 A

  The problem to be solved by the present invention is to provide a leakage inspection device and a leakage inspection method capable of quantitatively performing a leakage inspection of a high-pressure system of a fuel injection device.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, according to the present invention, there is provided a leakage inspection device for inspecting a leakage of a high-pressure system of a fuel injection device, wherein the fuel injection device is pressure-fed and pumped from a supply pump and the supply pump. A common rail for accumulating fuel, an injector for injecting fuel supplied from the common rail into a combustion chamber, a pressure detecting means for detecting the pressure of fuel accumulated in the common rail, and controlling fuel injection of the fuel injection device Control means, and the leakage inspection device accumulates fuel until the predetermined pressure is reached in the common rail by the supply pump under the control of the fuel injection device via the control means, and stops the injector If the pressure detected by the pressure detection means during a predetermined time is constant, the fuel injection device Those having a test control unit for determining leakage of the high pressure system is not.

  3. A leak inspection method for inspecting a fuel leak in a high-pressure system of a fuel injection device, wherein the fuel injection device includes a supply pump that pressurizes and pumps fuel, and a fuel that is pumped from the supply pump. A common rail for accumulating pressure, an injector for injecting fuel supplied from the common rail into a combustion chamber, pressure detecting means for detecting the pressure of fuel accumulated in the common rail, and control for controlling fuel injection of the fuel injection device And the fuel inspection method is configured to accumulate fuel until the common rail reaches a predetermined pressure by the supply pump under the control of the fuel injection device via the control means, and stop the injector. If the pressure detected by the pressure detecting means during a predetermined period is constant, the fuel injection device Leakage of pressure system are those determined not.

  According to the leakage inspection apparatus and the leakage inspection method of the present invention, the leakage inspection of the high-pressure system of the fuel injection device can be quantitatively performed.

The block diagram which showed the whole structure of the leak test | inspection apparatus which is embodiment. The flow figure which shows the flow of leak inspection control similarly. The time chart figure which similarly shows the flow of leak test control. The another time chart figure which shows the flow of leak inspection control similarly.

A leak inspection apparatus 10 according to the embodiment will be described with reference to FIG.
The configuration of the leak inspection apparatus 10 will be described.
The leak inspection apparatus 10 is an apparatus that inspects for a leak in the high-pressure system HPL of the fuel injection device 100. The leak inspection apparatus 10 includes an inspection controller 5 as inspection control means. The inspection controller 5 has a function of determining whether or not there is a leak in the high-pressure system HPL of the fuel injection device 100. The high-pressure system HPL of the fuel injection device 100 will be described later in detail. The inspection controller 5 is connected to an engine control unit 50 (hereinafter referred to as an ECU 50) as control means (to be described later) of the fuel injection device 100 and a pressure sensor 51 (to be described later).

The configuration of the fuel injection device 100 will be described.
The fuel injection device 100 is an inspection object by the leak inspection device 10. The fuel injection device 100 is provided in a diesel engine (not shown). The fuel injection device 100 includes a supply pump 20, a common rail 30, a plurality (four in this embodiment) of injectors 40, 40, 40, 40, an ECU 50 as control means, and a fuel tank 70. ing.

  The supply pump 20 is a pump that boosts the fuel. The supply pump 20 is connected to the fuel tank 70 via the low-pressure pipe LL1. A fuel filter 60 is disposed in the middle of the low-pressure pipe LL1. The supply pump 20 is connected to the common rail 30 via the high-pressure pipe HL1.

  The common rail 30 is a container that accumulates fuel in a high pressure state. The common rail 30 is connected to the supply pump 20 via the high-pressure pipe HL1. The common rail 30 is connected to the injectors 40, 40, 40, and 40 via high-pressure pipes HL2, HL2, HL2, and HL2. The common rail 30 is provided with a relief valve 31. The common rail 30 is connected to the fuel tank 70 via a relief valve 31 and a low pressure pipe LL2. A fuel filter 60 is disposed in the middle of the low-pressure pipe LL2. The common rail 30 is provided with a pressure sensor 51 as pressure detection means.

  The injectors 40, 40, 40, and 40 are valves that inject fuel by being opened. The injectors 40, 40, 40, 40 are arranged in a cylinder of a diesel engine. The injectors 40, 40, 40, 40 are connected to the common rail 30 via high-pressure pipes HL2, HL2, HL2, HL2. The injectors 40, 40, 40, 40 are connected to the fuel tank 70 via low-pressure pipes LL2, LL2, LL2, LL2. A fuel filter 60 is disposed in the middle of the low-pressure pipe LL2.

  The ECU 50 has a function of controlling fuel injection of the fuel injection device 100. More specifically, the ECU 50 has a function of controlling fuel injection by adjusting the injection timing or injection time of the injectors 40, 40, 40, 40. The ECU 50 has a function of driving the supply pump 20 to recognize the fuel pressure of the common rail 30 by the pressure sensor 51 and maintaining the common rail 30 at a constant fuel pressure. The ECU 50 is connected to a supply pump 20, a relief valve 31, injectors 40, 40, 40, 40, and a pressure sensor 51.

The function of the fuel injection device 100 will be described.
With the above-described configuration, the ECU 50 pressurizes the fuel by the supply pump 20 and pumps the fuel to the common rail 30. At this time, since the injectors 40, 40, 40, and 40 are closed, the pressure-fed fuel is accumulated in the common rail 30. The ECU 50 drives the supply pump 20, recognizes the pressure of the common rail 30 by the pressure sensor 51, and maintains the common rail 30 at a constant pressure. On the other hand, the ECU 50 causes the fuel in the common rail 30 to escape to the fuel tank 70 and maintain the common rail 30 at a constant pressure when the relief valve 31 reaches a set pressure or higher. The ECU 50 opens the injectors 40, 40, 40, 40 to inject fuel in the common rail 30 that is maintained at a constant pressure into the cylinder.

The high-pressure system HPL of the fuel injection device 100 will be described.
In the fuel injection device 100, the fuel is boosted to a maximum of about 160 MPa by the supply pump 20. Here, in the fuel injection device 100, a device or a pipe through which high-pressure fuel boosted by the supply pump 20 passes is defined as a high-pressure system HPL of the fuel injection device 100. In the fuel injection device 100, the path from the supply pump 20 through the common rail 30 to the injectors 40, 40, 40, 40 is the high-pressure system HPL. That is, in the fuel injection device 100, the supply pump 20, the high pressure pipe HL1, the common rail 30, the high pressure pipes HL2, HL2, HL2, and HL2, and the injectors 40, 40, 40, and 40 are connected to the high pressure system HPL (FIG. 1). In the shaded area).

The low pressure system LPL of the fuel injection device 100 will be described.
In the fuel injection device 100, the fuel is boosted to a maximum of about 160 MPa by the supply pump 20. However, in the fuel injection device 100, a device or piping that is not affected by the high-pressure fuel that is boosted by the supply pump 20 is defined as a low-pressure system LPL of the fuel injection device 100. In the fuel injection device 100, the fuel filter 60, the fuel tank 70, the low pressure pipe LL1, and the low pressure pipes LL2, LL2, LL2, LL2, and LL2 are included in the low pressure system LPL.

The flow of the leakage inspection control S100 will be described with reference to FIG.
In FIG. 2, steps performed by the operator are shown in parentheses, and steps performed by the inspection controller 5 via the ECU 50 are surrounded by a frame.

  The leakage inspection control S100 is control for performing a leakage inspection of the high-pressure system HPL of the fuel injection device 100. Note that the leak inspection of the low-pressure system LPL of the fuel injection device 100 is performed by a normal air leak inspection. The air leak test is a quantitative leak test in which air or nitrogen gas is sealed in a device or pipe to be inspected to obtain a predetermined pressure, and whether there is a leak is determined by a change in the predetermined pressure after a predetermined time has elapsed. .

  In step S <b> 110, the operator connects the inspection controller 5 to the ECU 50 and the pressure sensor 51. The inspection controller 5 and the ECU 50 are connected by a wire harness or the like. In the following steps, it is assumed that the inspection controller 5 issues a command to the fuel injection device 100 via the ECU 50. In step S120, the inspection controller 5 closes the relief valve 31 and the injectors 40, 40, 40, and 40. At this time, the high-pressure system HPL is in a sealed state. In addition, since the check valve is provided in the supply pump 20, the high pressure pipe HL1 and the low pressure pipe LL1 are cut off.

  In step S130, the inspection controller 5 drives the supply pump 20. In step S140, the inspection controller 5 recognizes the pressure of the common rail 30 (hereinafter, common rail pressure P) by the pressure sensor 51 while driving the supply pump 20. In step S150, the inspection controller 5 recognizes the common rail pressure P by the pressure sensor 51, and stops the supply pump 20 when the common rail pressure P reaches the predetermined pressure P1. In step S160, the inspection controller 5 stops the supply pump 20 in a state where the common rail pressure P becomes the predetermined pressure P1, and waits for a predetermined time T1. At this time, it is assumed that the inspection controller 5 continuously recognizes the common rail pressure P by the pressure sensor 51. The predetermined pressure P1, the predetermined time T1, and an allowable range ΔP described later are stored in advance in the inspection controller 5.

  In step S170, the inspection controller 5 confirms whether the common rail pressure P at the predetermined time T1 is constant. Specifically, the inspection controller 5 confirms whether the increase or decrease in the common rail pressure P within the predetermined time T1 is within the allowable range ΔP. The allowable range ΔP is a range in which the measurement error of the pressure sensor 51 is taken into consideration for the value of the predetermined pressure P1. In step S170, if the increase / decrease in the common rail pressure P is within the allowable range ΔP, the inspection controller 5 proceeds to step S180 and determines that there is no leakage in the high-pressure system HPL of the fuel injection device 100. On the other hand, if the increase / decrease in the common rail pressure P exceeds the allowable range ΔP in step S170, the inspection controller 5 proceeds to step S190 and determines that there is a leak in the high-pressure system HPL of the fuel injection device 100.

The flow along the time series of the leakage inspection control S100 will be described with reference to FIG.
Note that the horizontal axis of FIG. 3 indicates time series, and the vertical axis of FIG. 3 indicates the common rail pressure P. FIG. 3 shows a change in the common rail pressure P for the fuel injection device 100 when there is no leakage.

  With the start of the leak inspection control S100, the fuel is boosted by the supply pump 20 and is pumped to the common rail 30. At this time, since the high-pressure system HPL is in a sealed state, the common rail pressure P increases. When the common rail pressure P reaches the predetermined pressure P1, the supply pump 20 is stopped.

  If there is no leakage in the high-pressure system HPL of the fuel injection device 100, the common rail pressure P maintains the predetermined pressure P1. In the leakage inspection control S100, the common rail pressure P is assumed to be constant if the measurement error of the pressure sensor 51 is taken into consideration and the common rail pressure P is within the allowable range ΔP. If the common rail pressure P is maintained at the predetermined pressure P1 for the predetermined time T1, it is determined that there is no leakage in the high-pressure system HPL of the fuel injection device 100. The fuel is returned to the fuel tank 70 by the end of the leak inspection control S100. Thereafter, a test run of the diesel engine is performed.

The flow along the time series of the leakage inspection control S100 will be described with reference to FIG.
Note that the horizontal axis of FIG. 4 indicates time series, and the vertical axis of FIG. 4 indicates the common rail pressure P. FIG. 4 shows the change in the common rail pressure P for the fuel injection device 100 when there is a leak.

  With the start of the leak inspection control S100, the fuel is boosted by the supply pump 20 and is pumped to the common rail 30. At this time, since the high-pressure system HPL is in a sealed state, the common rail pressure P increases. When the common rail pressure P reaches the predetermined pressure P1, the supply pump 20 is stopped.

  If there is a leak in the high-pressure system HPL of the fuel injection device 100, the common rail pressure P decreases without being able to maintain the predetermined pressure P1. When the common rail pressure P cannot be maintained at the predetermined pressure P1 for the predetermined time T1, that is, when the common rail pressure P falls below the allowable range ΔP, it is determined that there is a leak in the high-pressure system HPL of the fuel injection device 100.

The effect of the leakage inspection control S100 will be described.
Conventionally, after a product has been assembled as the fuel injection device 100, only the low-pressure system LPL has been able to perform a leak test. In the low-pressure system LPL of the fuel injection device 100, air leak inspection is performed by enclosing air or nitrogen gas inside the device or piping.

  On the other hand, after the product was assembled as the fuel injection device 100, the high-pressure system HPL could not be inspected for leakage. In the high-pressure system HPL of the fuel injection device 100, when the diesel engine is test-started, the fuel is boosted to a maximum of about 160 MPa by the supply pump 20 and a visual leak inspection is only performed. In other words, the high-pressure system HPL of the fuel injection device 100 has not been subjected to quantitative leak inspection, and it cannot be said that sufficient quality assurance has been provided for fuel leakage.

  However, according to the leakage inspection control S100, the leakage inspection of the high-pressure system HPL of the fuel injection device 100 can be quantitatively performed. In addition, since the leakage inspection control S100 performs inspection using the ECU 50 and the pressure sensor 51 included in the fuel injection device 100, a device for the leakage inspection control S100 is not necessary, and it can be put into a production line at a low cost. Can be thrown in.

5 Inspection controller (Inspection control means)
DESCRIPTION OF SYMBOLS 10 Leak inspection apparatus 20 Supply pump 30 Common rail 40 Injector 50 Engine Control Unit (ECU) (control means)
100 Fuel injector HPL High pressure system LPL Low pressure system

Claims (2)

A leakage inspection device for inspecting leakage of a high-pressure system of a fuel injection device,
The fuel injection device includes:
A supply pump that boosts and pumps fuel,
A common rail for accumulating fuel pumped from the supply pump;
An injector for injecting fuel supplied from the common rail into a combustion chamber;
Pressure detecting means for detecting the pressure of fuel accumulated in the common rail;
Control means for controlling fuel injection of the fuel injection device;
Comprising
The leak inspection device is:
By the control of the fuel injection device through the control means, fuel is accumulated in the common rail by the supply pump until a predetermined pressure is reached, and the injector is stopped and detected by the pressure detection means during a predetermined time. If the pressure is constant, it comprises an inspection control means for determining that there is no leakage of the high-pressure system of the fuel injection device,
Leak inspection device. A leakage inspection method for inspecting fuel leakage in a high-pressure system of a fuel injection device,
The fuel injection device includes:
A supply pump that boosts and pumps fuel,
A common rail for accumulating fuel pumped from the supply pump;
An injector for injecting fuel supplied from the common rail into a combustion chamber;
Pressure detecting means for detecting the pressure of fuel accumulated in the common rail;
Control means for controlling fuel injection of the fuel injection device;
Comprising
The fuel inspection method includes:
By the control of the fuel injection device via the control means, fuel is accumulated in the common rail by the supply pump until a predetermined pressure is reached, and detected by the pressure detection means during a predetermined period in a state where the injector is stopped. If the pressure is constant, it is determined that there is no leakage of the high-pressure system of the fuel injection device.
Leak inspection method.

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