JP2013194649A - Fuel injection valve inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection valve inspection device capable of minimizing the time required for inspecting a fuel injection valve.SOLUTION: In inspecting a fuel injection valve before shipment, when an injection amount, a common rail pressure, an EGR valve, and various sensors are normal (S400: Yes), an intake temperature is in a predetermined range (S404: Yes), and an engine operating condition changes stably along with fuel injection from the fuel injection valve (S406: Yes), a fuel injection valve inspection device continues fuel injection from a fuel injection value for a predetermined judgment time which is shorter than the time taken until a measured value for an injection amount or a physical quantity related to the injection amount reaches a certain value so as to run the engine (S408). With an elapse of the predetermined judgment time, the measured value is compared with a judgment value (S410). When a difference between the measured value and the judgment value is in a predetermined range ( S412: Yes), the fuel injection valve is judged to be normal (S414). When the difference is not in the predetermined range (S412: No), the fuel injection valve is judged to be abnormal (S416).

Description

  The present invention relates to a fuel injection valve inspection device that inspects whether a manufactured fuel injection valve is normal or abnormal.

  Conventionally, it is inspected whether or not the fuel injection valve operates normally by actually operating the manufactured fuel injection valve before shipping (see, for example, Patent Document 1). In this case, it is conceivable to install a fuel injection valve in the internal combustion engine and measure a fuel injection valve injection quantity or a physical quantity related to the injection quantity in an environment where the fuel injection valve is actually used. By comparing the measured value with a target value corresponding to the measured value, it is checked whether or not the fuel injection valve is normal.

  However, when inspecting whether the fuel injection valve is normal or not in a new state before shipment, the fuel injection valve can be used even if the measured value measured immediately after the fuel injection valve is operated is compared with the target value. It is not possible to accurately check whether or not is normal or abnormal.

  This is because, for example, the contact amount between the nozzle needle that opens and closes the nozzle hole of the fuel injection valve and the valve seat and the sliding portion between the movable member and the support member are adapted by wear or the like, so that the injection amount becomes the injection command value. This is because the corresponding target injection amount is reached and becomes constant.

  Therefore, in order to inspect the fuel injection valve by comparing the measured value with a target constant value corresponding to the measured value, it is necessary to perform a break-in operation during the break-in time until the measured value reaches a constant value. . On the other hand, if the fuel injection valve or the physical quantity related to the injection amount is measured immediately after the break-in operation is started and the measured value is compared with the target constant value to determine whether the fuel injection valve is normal or abnormal, There is a risk of judging.

  Therefore, the running-in operation is performed for a normal fuel injection valve, and a predetermined running-in time until the measured value reaches a certain value is measured in advance. Based on the measured value when the running-in time has elapsed, the fuel injection valve It is conceivable to determine whether it is normal or abnormal.

  If the fuel injection valve is normal, the contact point and the sliding point become familiar after the break-in time has elapsed, and the measured value reaches a constant value. On the other hand, if the fuel injection valve is abnormal, the contact point and the sliding point become too fast or too slow, so that a constant value is reached before the break-in time has passed, or a constant value even if the break-in time has passed. Not reach.

JP 2003-328892 A

However, if the fuel injection valve is operated until the break-in time has passed for product inspection before shipment of the fuel injection valve, there is a problem that the inspection time becomes long.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fuel injection valve inspection device that shortens the inspection time of the fuel injection valve as much as possible.

  According to the invention described in claims 1 to 3, in the product inspection of the fuel injection valve, the measured value of the physical quantity related to the injection amount or the injection amount is acquired, and the measured value is obtained as the operating time of the fuel injection valve elapses. Before a predetermined time required to change and reach a certain value elapses, it is determined whether the fuel injection valve is normal or abnormal by comparing the measured value with a preset determination value.

  If the fuel injection valve is a normal fuel injection valve, the inventor determines that the measurement value varies for each fuel injection valve until the measurement value of the injection quantity or the physical quantity related to the injection quantity reaches a certain value after a predetermined time has elapsed. We focused on the fact that it does not change to reach a constant value, but changes within a predetermined range over time and reaches a constant value.

  Thereby, for example, a value before a predetermined time elapses can be set in advance as a determination value as a measurement value of a normal fuel injection valve. As a result, even before the predetermined time required for the measurement value to reach a certain value has elapsed, the fuel injection valve is normal or abnormal by comparing the measurement value with a preset determination value. Since it can be determined whether or not there is, the inspection time of the fuel injection valve can be shortened.

  According to the second aspect of the present invention, whether the fuel injection valve is normal or abnormal by comparing the amount of time change of the measured value with a preset determination value before the predetermined time elapses. Determine.

  As described above, the measured value changes within a predetermined range as time passes, so if the time variation of the measured value stabilizes after the start of inspection, the time variation of the measured value is set in advance as soon as possible after the start of inspection. By comparing with the determined determination value, it can be determined whether the fuel injection valve is normal or abnormal.

  Even if there is an error in the measured value itself, if the fuel injection valve is normal, the amount of time variation of the measured value should be within a predetermined range. Therefore, by comparing the time change amount of the measurement value with the determination value, it is possible to determine with high accuracy whether the fuel injection valve is normal or abnormal before the predetermined time elapses.

According to the invention described in claim 3, the physical quantity related to the injection quantity is the exhaust temperature or the output torque of the internal combustion engine.
Since the exhaust temperature and the output torque increase or decrease depending on the injection amount, the fuel injection valve can be inspected by measuring the exhaust temperature or the output torque. Further, since an exhaust sensor is installed in a normal exhaust system, the fuel injection valve can be inspected without preparing a measuring device for inspection at an exhaust temperature.

  The functions of the plurality of means provided in the present invention are realized by hardware resources whose functions are specified by the configuration itself, hardware resources whose functions are specified by a program, or a combination thereof. The functions of the plurality of means are not limited to those realized by hardware resources that are physically independent of each other.

The block diagram which shows the inspection system of the fuel injection valve by this embodiment. The flowchart which shows an inspection process. The time chart which shows the relationship between the operating time of a fuel injection valve, and a measured value.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. An inspection system 2 shown in FIG. 1 is a system that performs a product inspection before shipment with respect to a fuel injection valve 20 for a diesel engine (hereinafter also simply referred to as “engine”) 10, for example. 20, a flow rate measuring device 30, a torque measuring device 40, and an electronic control unit (ECU) 50. The fuel injection valve 20 is extracted for inspection every predetermined number of groups and attached to the engine 10.

  The engine 10 is provided with an intake / exhaust system, an EGR (Exhaust Gas Recirculation) system, a supercharging system, and a common rail type fuel supply system, as in the configuration actually used.

  The fuel supplied from the pump 22 is accumulated in a common rail (not shown) and supplied to the fuel injection valve 20. The flow rate measuring device 30 is injected from the fuel injection valve 20 installed in each of the four cylinders from the difference between the fuel flow rate supplied from the pump 22 to the engine 10 side and the fuel flow rate returned from the engine 10 side. Measure the injection amount.

The torque measuring device 40 is connected to the crankshaft of the engine 10 and measures the output torque of the engine 10.
The ECU 50 is an ECU that controls the operating state of the engine 10 during normal operation. From an unillustrated temperature sensor, pressure sensor, and intake air amount sensor, exhaust purification such as exhaust temperature, supercharging pressure, DPF (Diesel Particulate Filter), etc. Inputs signals for detecting engine operating conditions such as the differential pressure of the device, common rail pressure, and intake air amount.

  Further, the ECU 50 shifts from the normal operation mode to the check mode in which the fuel injection valve 20 is inspected in accordance with an instruction from an operation terminal such as a personal computer (not shown) connected to the ECU 50. In the check mode, the ECU 50 inputs the fuel injection amount from the flow rate measuring device 30 and inputs the output torque of the engine 10 from the torque measuring device 40.

(Inspection process)
Next, the inspection process of the fuel injection valve 20 will be described based on the flowchart of FIG. The flowchart in FIG. 2 is executed by the ECU 50 based on an inspection program stored in the ROM when a check mode for inspecting the fuel injection valve 20 is instructed by an instruction from the operation terminal.

When the check mode is instructed, the ECU 50 determines whether (1) the injection amount, (2) the common rail pressure, (3) the EGR valve, and (4) various sensors are normal or abnormal. When the following conditions are satisfied, it is determined as normal.
(1) Injection amount The injection command value is not a value at the time of fail-safe but a value at a normal operation state.
(2) Common rail pressure The difference between the actual common rail pressure and the target common rail pressure is within the specified range.
(3) EGR valve The EGR valve that controls the exhaust gas circulation amount in the EGR system normally opens and closes, and the difference between the actual opening and the target opening is within a predetermined range.
(4) Various sensors The output is not fixed at a low level or a high level, and changes within a predetermined range.

If there is an abnormality in any of the items (1) to (4) in the above determination (S400: No), the check mode is stopped and the operation proceeds to fail-safe operation (S402).
When all the items are normal in the above determination (S400: Yes), it is determined whether or not the intake air temperature is within a predetermined range, that is, whether or not the external environment of the inspection system 2 is suitable for the inspection (S404). . If the intake air temperature is outside the predetermined range and too high or too low (S404: No), the process proceeds to S400, and if the intake air temperature is within the predetermined range (S404: Yes), the process proceeds to S406.

  Next, when the operating state of the engine 10 is unstable, the inspection of the fuel injection valve 20 cannot be performed properly, so that the engine operation is performed in response to an increase in the injection amount of the fuel injection valve 20 due to the break-in operation for the inspection. It is determined whether or not the state has changed stably (S406).

  Whether or not the engine operating state is stably changing is determined by measuring the measured value and the target value for the intake air amount, the boost pressure, the differential pressure of the exhaust purification device such as DPF, the exhaust temperature, and the like as parameters representing the engine operating state. This is done by determining whether or not the difference is within a predetermined range. The target value to be compared with each measured value is obtained from a map that is referred to from the engine speed and the target injection amount.

  The target injection amount corresponding to the injection command value for the fuel injection valve 20 is a constant value regardless of the elapsed time of the inspection, but as the inspection time elapses, the contact location and the sliding location of the fuel injection valve 20 become familiar. The amount increases. When the engine speed increases due to an increase in the injection amount, the target value of the parameter representing the engine operating state also increases.

  If the difference between the measured value and the target value of any of the above parameters representing the engine operating state is out of the predetermined range (S406: No), the process returns to S400. If the difference between all the measured values of the above parameters representing the engine operating state and the target value is within a predetermined range (S406: Yes), the fuel injection from the fuel injection valve 20 is continued for a predetermined determination time and the engine 10 is operated. Drive (S408).

  At this time, the contact point and the sliding point of the fuel injection valve 20 are adjusted by wear or the like along with the operation of the fuel injection valve 20, and as shown in FIG. This is a time shorter than a predetermined break-in time required for the measured value of the related physical quantity to change to reach a target value. The predetermined break-in time is measured and set in advance by attaching a normal fuel injection valve 20 to the engine 10 and running-in.

  After a predetermined determination time has elapsed, the fuel injection amount acquired from the flow measuring device 30, the output torque of the engine 10 acquired from the torque measuring device 40, or the exhaust temperature acquired from the exhaust temperature sensor installed in the exhaust pipe of each cylinder. The measured value of the physical quantity that changes in relation to the injection quantity, for example, is compared with the judgment value that is reached after a predetermined judgment time if the fuel injection valve 20 is normal (S410). The output torque and the exhaust temperature increase as the inspection time elapses and the injection amount increases.

  When comparing the measured value and the judgment value, the value of the measurement value itself after a predetermined judgment time has passed may be compared with the corresponding judgment value, or the time variation of the measurement value and the judgment value corresponding thereto May be compared. The determination value is measured and set in advance by attaching a normal fuel injection valve 20 to the engine 10 and running-in.

  When comparing the time change amount and the determination value, the average time change amount from the determination that the engine operating state has stably changed in S406 to the elapse of a predetermined determination time is used as the determination value. You may compare, and you may compare the amount of time change at that time when predetermined determination time passed with a determination value.

  In FIG. 3, the solid line indicates the reference characteristic value 200 of the measurement value when the fuel injection valve 20 is normal, and the dotted line and the alternate long and short dash line indicate examples of the actual measurement values 202 and 204 of the fuel injection valve 20 to be inspected. ing. When a predetermined determination time has elapsed, if the difference between the reference characteristic value 200 as the determination value itself or the amount of change over time is within a predetermined range, such as the measured value 202 (S412: Yes), fuel injection It is determined that the valve 20 is normal (S414). In this case, the corresponding group of fuel injection valves 20 is shipped.

  If the difference from the reference characteristic value 200, which is a determination value, or the time change amount is out of the predetermined range as in the measurement value 204 (S412: No), it is determined that the fuel injection valve 20 is abnormal. (S416). In this case, the shipment of the group of the corresponding fuel injection valve 20 is temporarily stopped.

  When the exhaust temperature is used as a measured value, the exhaust temperature is acquired from an exhaust temperature sensor installed in the exhaust pipe of each cylinder, so whether the fuel injection valve 20 is normal or abnormal is determined for each cylinder based on the exhaust temperature. it can. On the other hand, the injection amount or the output torque is acquired as the total of all four cylinders. That is, it can be determined that all the fuel injection valves 20 of the four cylinders are normal or any of the fuel injection valves 20 is abnormal, but it is not possible to specify which cylinder of the fuel injection valves 20 is abnormal.

  Therefore, in order to identify the abnormal fuel injection valve 20, it is effective to inspect based on the exhaust temperature. In addition, since the exhaust temperature sensor is a sensor that is normally installed to control the engine operating state, it is not necessary to install a new measuring device to inspect the fuel injection valve 20.

On the other hand, it is effective to use the injection amount as a measured value from the point of checking the normality and abnormality of the fuel injection valve 20 with high accuracy. In this case, any configuration that can measure the injection amount for each cylinder is desirable.
In the above-described embodiment, if the fuel injection valve 20 is a normal fuel-injection valve 20, when a break-in operation is performed in a new state, the contact portion and the sliding portion become familiar with wear over time, and the injection amount or the injection amount. A predetermined break-in time in which the physical quantity related to is gradually changed from the initial value and reaches a constant value is measured in advance, and before the elapsed time of the break-in operation reaches the break-in time, the injection amount or injection of the fuel injection valve 20 Whether the fuel injection valve is normal or abnormal is determined based on whether the measured value of the physical quantity related to the quantity is within a predetermined range with respect to the determination value. Thereby, the inspection time of the fuel injection valve 20 can be shortened compared with the case where it is determined whether or not the measured value of the fuel injection valve 20 has reached a constant value after the break-in time has elapsed.

  In the above embodiment, the predetermined break-in time corresponds to the predetermined time of the present invention, and the ECU 50 corresponds to the fuel injection valve inspection device of the present invention. The ECU 50 functions as a measurement value acquisition unit, a determination unit, and a change amount calculation unit of the present invention.

  Further, the process of acquiring the measured value of the fuel injection amount, output torque or exhaust temperature in S410 of FIG. 2 corresponds to the function executed by the measured value acquisition means of the present invention, and the fuel injection amount, output torque or exhaust temperature in S410. When calculating the time change amount from the measured value, the process corresponds to the function executed by the change amount calculating means of the present invention, and the process of S412 corresponds to the function executed by the determining means of the present invention.

[Other Embodiments]
In the above embodiment, the present invention is applied to the inspection of the fuel injection valve 20 for the diesel engine. However, if the manufactured fuel injection valve before shipment is inspected to be normal or abnormal, the present invention is applied. The inspection object is not limited to a fuel injection valve for a diesel engine, but may be a fuel injection valve for a gasoline engine, for example.

  In the above embodiment, the ECU 50 for engine control also serves as an inspection device for the fuel injection valve 20. However, even if the fuel injection valve 20 is judged normal or abnormal by a device dedicated to product inspection of the fuel injection valve 20. Good.

  In the above-described embodiment, the functions of the measurement value acquisition unit, the determination unit, and the change amount calculation unit are realized by the ECU 50 whose functions are specified by the inspection program. On the other hand, at least some of the functions of the plurality of means may be realized by hardware whose functions are specified by the circuit configuration itself.

  As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

10: engine (internal combustion engine), 20: fuel injection valve, 50: ECU (fuel injection valve inspection device, measurement value acquisition means, determination means, change amount calculation means)

Claims (3)

Measurement value acquisition means for acquiring a measurement value of an injection amount of the fuel injection valve or a physical quantity related to the injection amount in a product inspection performed by operating the fuel injection valve with the fuel injection valve assembled in an internal combustion engine When,
The measured value is preset with the measured value acquired by the measured value acquisition means before the predetermined time required for the measured value to change and reach a certain value as the operating time of the fuel injection valve elapses. Determining means for determining whether the fuel injection valve is normal or abnormal by comparing with a determined value;
A fuel injection valve inspection device comprising: A change amount calculation means for calculating a time change amount of the measurement value acquired by the measurement value acquisition means;
The determination means compares the time change amount calculated by the change amount calculation means with a predetermined determination value before the predetermined time elapses to determine whether the fuel injection valve is normal or abnormal. Determine if there is,
The fuel injection valve inspection device according to claim 1.   The fuel injection valve inspection device according to claim 1, wherein the physical quantity is an exhaust temperature or an output torque of the internal combustion engine.

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