JPH11153070A - Inspection device for fuel injection pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate inspection of an injection maximum pressure by unevenness in a machine difference by a novel constitution. SOLUTION: A pump 1 is provided with an electromagnetic spill valve 22 to intercommunicate a pump 11 to pressurize fuel through operation of a plunger 10 and a fuel chamber 5 on the low pressure side for terminating fuel injection and a cam angle sensor. An ROM 38 stores a machine difference correction amount at a rated point A and the machine difference correction amount at a low load correction point B in a relation between the number of revolutions and a fuel injection completion timing, and corrects unevenness in the machine difference based on a fuel injection completion timing according to engine operation. A microcomputer 50 calculates a difference between the machine difference correction amount at a rated point A and the machine difference correction amount at a correction point B. When a difference in the machine difference correction amount is deviated from a given range, it is decided that the injection maximum pressure of the pump 1 is outside an allowance range, the pump is eliminated and a delivery is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection device for a fuel injection pump in a diesel engine, and more particularly to an inspection device for checking a pumping capacity.

[0002]

2. Description of the Related Art In order to realize a high-output diesel engine that satisfies exhaust gas regulations, a particularly high pumping pressure has recently been required for a fuel injection pump. More specifically, as shown in FIG. 10, the higher the maximum injection pressure of the pump, the higher the engine output can be. That is, the higher the injection pressure, the more excellent the fuel atomization and atomization, and a higher output can be obtained. Further, as shown in FIG. 11, in relation to NO _x emissions and particulate emissions, in order to clear the regulation value for satisfying the low NO _x emissions, lower particulate emissions, high injection It must be a pressure pump.

[0003] Against this background, the maximum injection pressure of the fuel injection pump is measured, and pumps that do not produce the desired maximum injection pressure due to machine-to-machine variation (variation in pumping capacity) must be eliminated at the stage of shipment from the factory. I have to do it.

For this purpose, as shown in FIG. 12, a pressure sensor 61 is attached to a discharge portion of a fuel injection pump 60,
As shown in FIG. 13, there is a method of measuring the maximum pressure directly from the output signal of the pressure sensor 61.

However, in order to inspect the maximum injection pressure of the fuel injection pump by such a method, a pressure sensor 61 is required. If the pressure sensor 61 is incorrectly calibrated, the pressure cannot be detected accurately and the injection cannot be performed. It is difficult to determine the quality of the pump.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a fuel injection pump inspection apparatus that can easily inspect the maximum injection pressure due to machine-to-machine variation with a novel configuration. Its purpose is to provide.

[0007]

According to a first aspect of the present invention, there is provided an apparatus for inspecting a fuel injection pump including an electromagnetic spill valve, a cam angle sensor, and a machine difference correction amount storage means, A calculating means for calculating a difference or a ratio between the machine difference correction amount at the high speed / high load correction point and the machine difference correction amount at the other correction points; and a difference or ratio of the machine difference correction amount by the calculating means within a predetermined range. In addition, the gist of the present invention is a fuel injection pump inspection device including: a determination unit that determines that the maximum injection pressure of the pump is out of an allowable range.

Accordingly, the calculating means calculates the difference or ratio between the machine difference correction amount at the high speed / high load correction point and the machine difference correction amount at the other correction points, and the judging means calculates the machine difference correction amount by the calculating means. When the difference or the ratio is out of the predetermined range, it is determined that the maximum injection pressure in the pump is outside the allowable range.

For example, when making a determination based on the difference between the machine difference correction amounts, as shown in FIG. 9, the difference between the correction amount at the rated point and the correction amount at the other correction points is determined by the fact that the injection maximum pressure is The lower the difference, the greater the difference from the correction amount. Therefore, by setting the threshold at the time of determining the difference between the correction amount corresponding to the injection maximum pressure P _MAX in need (determination level), to identify and eliminate pump less than the injection maximum pressure P _MAX in need be able to.

That is, as the breakdown of the correction amount due to the machine-to-machine variation, there are (i) a variation in a pumping ability due to an error in a cam profile and a clearance error in a sliding portion, and (ii) a variation due to a mounting error in a cam angle sensor. Therefore, at the rated point, the sum of (i) and (ii) is the correction amount, and at the other correction points, the correction amount is only (ii). The difference between the correction amount at the rated point and the correction amount at the correction point is By taking the ratio, it is possible to detect variations in the pumping capacity (injection maximum pressure).

As described above, when the method as shown in FIG. 12 is employed, the pressure sensor 61 is required, and if the calibration of the sensor 61 is wrong, the pressure cannot be accurately detected, and it is difficult to determine the quality of the injection pump. However, according to the present invention, it is possible to easily inspect the maximum injection pressure due to the machine-to-machine variation without using a pressure sensor with a novel configuration.

[0012] Here, as described in claim 2, the calculating means is configured to calculate the machine difference correction amount at the point of high speed and high load and the low speed / high load.
If the difference or ratio with the machine difference correction amount at the low load correction point is calculated, it is practically preferable.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an overall configuration of a fuel injection device including a fuel injection pump to be inspected. The fuel injection device according to the present embodiment uses an inner-cam type distribution type fuel injection pump to inject and supply fuel from the pump to a diesel engine. The fuel injection amount and fuel injection timing are controlled by an electronic control unit (hereinafter referred to as an ECU). ). Hereinafter, the configuration of the fuel injection control device will be described in detail.

As shown in FIG. 1, a drive shaft 3 that rotates at a half speed in synchronization with a crankshaft (not shown) of the engine is inserted through a pump housing 2 of the fuel injection pump 1. A pump housing 2 is provided with a vane-type feed pump 4 (shown in a 90-degree view in FIG. 1). The feed pump 4 sucks up fuel and pressurizes the fuel as the drive shaft 3 rotates, and a passage (not shown). To the feed gallery 5a forming a part of the low pressure side fuel chamber 5.

A distribution rotor 6 that rotates integrally with the drive shaft 3 is connected to a tip end (right end in the figure) of the drive shaft 3. The distribution rotor 6 is rotatably housed in a cylinder 7 provided in the pump housing 2. Have been. An inner cam ring 8 is attached to the pump housing 2, and the head portion 6 a of the distribution rotor 6 slides and rotates along a cam surface 8 a on the inner circumference of the inner cam ring 8. In addition,
The cam surface 8a has the number of engine cylinders (4 in this embodiment).
One) cam mountain. The details are shown in FIG. 2, a radially extending cylindrical hole 9 is formed in the head portion 6a of the distribution rotor 6, and a pair of plungers 10 are slidably disposed in the cylindrical hole 9. A pump chamber 11 as a fuel pressurizing chamber is formed between the pair of plungers 10. A shoe 12 is disposed at an outer end of the plunger 10, and a roller 13 is rotatably held on the shoe 12.

Therefore, when the roller 13 slides along the cam surface 8a of the inner cam ring 8 with the rotation of the distribution rotor 6, the roller 13, the shoe 12, and the plunger 10 reciprocate integrally in the radial direction of the distribution rotor 6. I do. Then, fuel is sucked into the pump chamber 11 when the plunger 10 moves outward in the radial direction of the distribution rotor 6 according to the cam profile defined by the cam surface 8a, and the fuel is pressurized when moving inward in the radial direction. The fuel is pumped from the pump chamber 11.

The distribution rotor 6 includes the pump chamber 1.
A suction port 14, a distribution port 15, a spill port 16, and a spill annular groove 16a communicating with 1 are formed.
The suction port 14 communicates with the feed gallery 5a via the communication passage 17a of the cylinder 7 in FIG.
Is communicated with the injection passage 18 via the communication passage 17b of the cylinder 7. The spill port 16 communicates with the spill annular groove 16a.
The communication path 17c communicates with the spill passage 19. The spill passage 19 communicates with the low pressure side fuel chamber 5. In addition, the delivery valve 20 is provided in the aforementioned injection passage 18.
The fuel is supplied from the delivery valve 20 to the fuel injection nozzle 21.

In the middle of the spill passage 19, an electromagnetic spill valve (electromagnetic injection amount control valve) 22 is arranged. The electromagnetic spill valve 22 includes a valve 23 for opening and closing the spill passage 19, a spring 24 for urging the valve 23 in a valve opening direction (upward in the figure), and a valve closing direction by excitation. (Downward in the figure). An annular high-pressure fuel chamber 26 for introducing high-pressure fuel is formed around the valve body 23. That is, when the solenoid coil 25 is not energized, the electromagnetic spill valve 22 is opened (the state shown in the drawing), and the fuel pumped from the pump chamber 11 is spilled to the low-pressure side fuel chamber 5 via the spill passage 19 and the high-pressure fuel chamber 26. (Leaked). Also, when the solenoid coil 25 is energized, the electromagnetic spill valve 22 is closed, fuel spill from the pump chamber 11 to the low-pressure side fuel chamber 5 is stopped, and the distribution port 1
The fuel is sent to the fuel injection nozzle 21 via 5.

Further, a hydraulic timer 27 (shown in a 90-degree development in FIG. 1) is built in the lower part of the pump housing 2. The timer 27 is operated by the fuel pressure of the feed gallery 5a. A timer piston 29 disposed in a timer housing 28 is connected to the inner cam ring 8 via a slide pin 30. In the timer housing 28, fuel sucked into the feed pump 4 is introduced into the low-pressure chamber 31, and fuel from the feed gallery 5 a (fuel discharged from the feed pump 4) is introduced into the high-pressure chamber 32. Then, due to the balance between the urging force of the timer spring 33 disposed on the low-pressure chamber 31 side and the fuel pressure in the high-pressure chamber 32, the timer piston 29 slides in the left-right direction in the drawing, and the inner cam ring 8 rotates.

The fuel pressure of the timer 27 is adjusted by a timer control valve (TCV) 34. That is, in the timer housing 28, the low-pressure chamber 31 and the high-pressure chamber 32 communicate with each other through the communication passage 35, and the fuel pressure in the high-pressure chamber 32 is adjusted by opening and closing the timer control valve 34 by duty ratio control. Then, the position of the timer piston 29 is adjusted with the adjustment of the fuel pressure in the high-pressure chamber 32 by the timer control valve 34. Then, the lift timing of the plunger 10 is adjusted according to the rotation of the inner cam ring 8, and the fuel injection timing is controlled. The longer the drive (ON) time of the timer control valve 34, that is, the larger the command duty ratio signal, the more the fuel injection timing is controlled to the retard side, and the shorter the drive (ON) time, that is, the command duty ratio signal. Is smaller, the fuel injection timing is controlled to be advanced.

On the other hand, a pulsar 36 having a plurality of protrusions on the outer peripheral surface is attached to the drive shaft 3, and the pulsar 36 rotates in synchronization with the drive shaft 3. A cam angle sensor 37 facing the outer peripheral surface of the pulsar 36 is attached to the inner cam ring 8. As shown in FIG. 3, the pulsar 36 has 96
Protruding teeth are provided at equal intervals, and the tooth spacing is 3.75 ° (corresponding to 7.5 ° CA). Further, on the outer periphery of the pulsar 36, there are provided toothless portions 36a in which a predetermined number (for example, two) of teeth are missing at four positions corresponding to the number of all cylinders. Cam angle sensor 3
7 is a magnet 37a and an electromagnetic pickup coil 37b
And detects passage of teeth on the outer periphery of the pulsar 36, and outputs a detection signal at each predetermined cam angle. This detection signal is input to the ECU 40 of FIG. 1 and the waveform is shaped (binarized) in the ECU 40. The cam angle corresponding to the cam lift accompanying the rotation of the drive shaft 3 can be detected from the signal after the waveform shaping.

In FIG. 1, an ECU 40 includes a CPU (Central Processing Unit) 4 for executing various arithmetic programs.
1 and a memory 42 for storing various arithmetic programs and map data. In addition, the present apparatus includes an accelerator opening sensor 43 for detecting the amount of depression of the accelerator pedal by the driver, a water temperature sensor 44 for detecting the temperature of the engine cooling water, and the like. The signal is input to ECU40.

The CPU 41 detects a cam angle based on a detection signal from the cam angle sensor 37, determines a cylinder, calculates an engine speed (pump speed), and based on a detection signal from the accelerator opening sensor 43. The calculated accelerator opening is calculated. Further, the CPU 41 controls the opening and closing of the electromagnetic spill valve 22 for adjusting the fuel injection amount and the timer control valve for adjusting the fuel injection timing based on these engine operating conditions (engine speed, accelerator opening, etc.). The duty control of 34 is performed. Particularly, in the present embodiment, the control target is the electromagnetic spill valve 22, and the fuel injection control by opening and closing the spill valve 22 will be mainly described.

The fuel injection is performed as follows. FIG.
Indicates the operation at the time of injection. In the figure, time t1 is N
The output timing of the reference position (corresponding to the rising edge of the pulse immediately after the tooth missing portion) obtained based on the tooth missing portion 36a of the e-pulse (binary signal of the signal detected by the cam angle sensor 37) is shown. Time t2 indicates the timing at which the electromagnetic spill valve 22 is opened.

In such a case, the pressure feeding start time corresponds to the lift start time of the plunger 10. Further, the pressure feed end timing is determined by the valve opening timing (time t2) of the electromagnetic spill valve 22, which is determined by the angle θ (de) from the reference position (time t1).
g). At this time, “θ” is obtained based on the engine operating conditions (engine speed, accelerator opening, etc.) at that time, and a desired fuel injection amount (mm ³ / st) is obtained. Is a spill timing (spill timing) at which the electromagnetic spill valve 22 is opened to spill high-pressure fuel, and at the same time, is an injection end timing at which fuel injection is ended. That is, the electromagnetic spill valve 22 functions as an injection amount control valve. Note that the fuel pressure changes as shown.

As described above, the present injection control device detects the cam phase based on the signal from the cam angle sensor 37 synchronized with the cam phase (cam lift), and outputs the cam phase commanded by the ECU 40 to obtain a predetermined injection amount. At this time, the spill valve (injection amount control valve) 22 opens and the injection ends.

The pump 1 shown in FIG. 1 is provided with a ROM 38 as storage means, and this ROM 38 stores in advance data relating to machine difference (injection amount machine difference correction data). Specifically, as shown in FIG. 5, the pump rotation speed N is set on the first axis (x-axis) in the orthogonal three-axis system coordinates.
P, the second axis (y-axis) takes the valve opening timing θ (corresponding to the injection amount Q) of the spill valve 22, and the third axis (z-axis) relates to the valve opening timing of the spill valve 22. The correction amount Δθ is taken. In FIG. 5, eight points are set as correction points for performing the correction. Specifically, the rotation speed N
1 (for example, 100 rpm) and the rotation speed N2 (for example, 500
rpm), the rotation speed N3 (for example, 1000 rpm), and the spill timing θ1 at the rotation speed N4 (for example, 1500 rpm).
(For example, 10 mm ³ / st) and the correction amount Δθ at the spill timing θ 2 (for example, 70 mm ³ / st) are stored in advance. Here, the point (N4, θ2) is the maximum rotation speed and the maximum load, and is the rated point A. That is, the rated point A is a condition that requires a high injection pressure (high speed / high injection amount). The correction point B is (N3, θ1) where the number of revolutions and the load are one rank lower than the rated point A.

As described above, the ROM 38 stores the mechanical error correction amount Δθ ₄₂ at the rated point A and the mechanical error correction amount Δθ at at least another correction point B in relation to the pump rotation speed NP and the fuel injection end timing θ. I remember ₃₁ . Based on this data (correction amount Δθ), correction relating to the machine-to-machine variation is performed on the fuel injection end timing θ according to the engine operation.

The measurement of the correction amount Δθ stored in the ROM 38 is carried out prior to the inspection as to whether or not the pump has a maximum injection pressure when shipped from a factory. In addition, FIG.
The PU 41 performs fuel injection control as follows. As shown in FIG. 6, the CPU 41 determines in step 100 that the pump speed N
P, the accelerator opening ACCP and the engine coolant temperature TW are taken in, and in step 101, the basic injection amount Q _BASE is calculated from the pump rotation speed NP and the accelerator opening ACCP. And C
PU41 calculates the correction injection amount Q _REV from the engine coolant temperature TW at step 102. Further, in step 103, the CPU 41 _obtains the sum of the basic injection amount Q _BASE and the corrected injection amount Q _REV (= Q _BASE + Q _REV ), and calculates this as the final injection amount Q _FIN.
To be stored.

Then, in step 104, the CPU 41 performs a conversion process of the injection amount Q / spill timing θ. More specifically, a plurality of characteristic lines for obtaining the pre-correction spill timing θbef using the final injection amount Q _FIN and the pump rotation speed NP as elements are prepared, and correction is performed based on the final injection amount Q _FIN and the pump rotation speed NP at that time. Find the previous spill timing θbef. In step 105, the CPU 41 calculates a correction amount Δθ by interpolation from the pump rotation speed NP and the spill timing θbef before correction using the data of FIG.

Then, in step 106, the CPU 41 adds the correction amount Δθ to the spill timing θbef before correction to obtain the final spill timing θ _FIN . In step 107, the CPU 41 outputs the final spill timing θ _FIN as a command signal.

As described above, since each pump has a variation in pumping capacity and a phase shift between the pump and the cam / cam angle sensor 37, the electromagnetic spill valve (injection amount control valve) has the same timing. In fact, even when the valve 22 is opened, the injection amount varies. For this reason, as shown in FIG. 5, in other words, how much the injection amount of each pump differs from the master pump at the center (standard as designed) at a plurality of points of the rotational speed NP and the spill timing θ. For example, it is detected how much the phase (timing) of opening the spill valve 22 should be corrected to obtain the same injection amount as that of the master pump, and this value is written in the ROM 38 provided for each pump, and the pump is shipped.

FIG. 7 is a configuration diagram of the inspection device for the fuel injection pump 1 described above. In FIG. 7, a microcomputer 50 as a calculation means and a determination means is for calculating a correction amount in the ROM 38 of the fuel injection pump 1 and for inspecting the maximum injection pressure. The microcomputer 50 includes a memory 51, and can temporarily store various data. Also,
The fuel injection pump 1 is connected to the microcomputer 50. That is, the electromagnetic spill valve 22, the ROM 38, and the timer control valve (TCV) 34 are connected to the microcomputer 50. Further, an injection fuel amount measuring device 39 is attached to the discharge side of the fuel injection pump 1. Injected fuel meter 3
Numeral 9 measures the amount of fuel discharged from the fuel injection pump 1, and the measurement result is sent to the microcomputer 50. Further, an alarm lamp 52 is connected to the microcomputer 50.

Next, the operation of the inspection device for the fuel injection pump 1 configured as described above will be described. After assembling the pump 1 at the factory, the connection is made as shown in FIG. Then, the microcomputer 50 causes the fuel injection to be performed at a predetermined pump rotational speed NP and a predetermined injection end timing θ in order to obtain the correction amount Δθ at each point in FIG. The difference Δθ is converted into a difference Δθ of the injection end timing, and this is temporarily stored in the memory 51. This operation is performed for all eight points in FIG.

Subsequently, the microcomputer 50
The processing of FIG. 8 is executed. The microcomputer 50 is
Correction amount [Delta] [theta] ₄₂ at the rated point A at step 200 is read (see FIG. 5), reads the correction value [Delta] [theta] ₃₁ at the correction point B (see FIG. 5) at step 201. Then, the microcomputer 50 calculates Δθ ₄₂ −Δθ ₃₁ in step 202 to obtain a difference X (= Δθ ₄₂ −Δθ ₃₁ ). That is, the difference X between the correction amounts of the two points on the high injection pressure side and the low injection pressure side is obtained.

Then, the microcomputer 50 determines whether or not the value of X is within a predetermined range in step 203. If the value is within the range, the microcomputer 50 compares each correction amount Δθ temporarily stored in the memory 51 in step 204 with the pump 1. In a predetermined storage area of the ROM 38. On the other hand, the microcomputer 50
Turns on the alarm lamp 52 in step 205 when the value of X exceeds a predetermined range. As a result, the worker is inferior in the maximum injection pressure of the pump 1 (abnormal pumping ability).
Is excluded at the shipping stage and is not shipped.

That is, as shown in FIG.
Injection pressure and X value (= Δθ ₄₂−Δθ₃₁Relationship with
The maximum injection pressure at rated point A is
The absolute value of X tends to become smaller as it gets closer,
Injection pressure P_MAXIf you know
The X value is equal to a predetermined value (threshold) in step 203 of FIG.
Is set.

That is, FIG. 9 shows the difference X between the "ROM entry information at point A in FIG. 5 where the highest pressure is required" and the "ROM entry information at point B in FIG. 5 where the pressure is low".
This indicates that there is a close correlation between the pump information and the pumping performance. When the difference between the above described information at the two points A and B exceeds a predetermined range, the pump has abnormal pumping performance. Can be determined (determined as defective).

That is, as a breakdown of the correction amount due to the machine-to-machine variation, (i) an error of the cam profile and an error of the clearance of the sliding portion as shown by L1 in FIG. (Ii) mounting error of the cam angle sensor 37 in FIG. 3 (output of the cam lift and cam angle sensor as indicated by L2 in FIG. 4) due to the clearance error of the outer peripheral surface and the clearance error of the outer peripheral surface of the plunger 10. There is variation due to signal phase shift). At the rated point A, the sum of (i) and (ii) becomes the correction amount, and at the correction point B, only (ii) becomes the correction amount.
By taking the difference between the correction amount at the correction point B and the correction amount at the correction point B, the variation in the pumping ability, that is, the maximum injection pressure can be detected.

As described above, this embodiment has the following features. (A) The microcomputer 50 of FIG. 7 calculates the difference X between the machine difference correction amount at the rated point A and the machine difference correction amount at the correction point B in steps 200 to 202 in FIG.
In step 3, if the difference X in the machine difference correction amount is out of the predetermined range, it is determined that the maximum injection pressure of the pump 1 is out of the allowable range.
Was turned on.

That is, as shown in FIG. 9, the difference X between the correction amount at the rated point A and the correction amount at the correction point B reflects the variation in pumping capacity (injection maximum pressure). By using the difference in the correction amount corresponding to the required maximum injection pressure as the threshold value for determination, it is possible to specify and exclude a pump that does not satisfy the required maximum injection pressure.

In addition to those described above, the present invention may be implemented as follows. In the above embodiment, the case where the present invention is applied to an inner cam type distribution type fuel injection pump is described. However, the present invention may be applied to a face cam type distribution type fuel injection pump.

Further, a difference X between the correction amount at the rated point A and the correction amount at the correction point B is obtained. If the difference X is out of a predetermined range, it is determined that the maximum injection pressure of the pump is out of the allowable range. Although the judgment was made, the ratio between the correction amount at the rated point A and the correction amount at the correction point B was obtained, and when the ratio was out of the predetermined range,
It may be determined that the maximum injection pressure of the pump is outside the allowable range.

Further, instead of calculating the difference or ratio between the correction amount at the rated point A and the correction amount at the correction point B in FIG. 5, the correction amount at the rated point A in FIG. The difference or ratio between the correction amount and the correction amount at the correction point may be determined, and if the difference or ratio is out of the predetermined range, the maximum injection pressure of the pump may be determined to be outside the allowable range.

Further, in the above-described embodiment, the microcomputer 50 is provided in the ROM 3 of the fuel injection pump 1.
8 and the inspection of the maximum injection pressure were performed.
After the correction amount has been stored in the pump 38, a microcomputer for inspection is connected to the pump 1, and the microcomputer calculates the difference between the correction amount at the rated point A and the difference amount at the correction point B in the ROM 38. The difference or ratio with the correction amount may be calculated, and if the difference or ratio deviates from a predetermined range, it may be determined that the maximum injection pressure of the pump is outside the allowable range.

Further, a case will be described where the correction data stored in the ROM 38 is a correction amount Δθ in the relationship between the rotational speed and the fuel injection end timing, and the fuel injection end timing θ according to the engine operation is corrected for the machine difference Δθ. However, the correction data stored in the ROM 38 is defined as a correction amount ΔQ in the relationship between the rotation speed N and the injection amount Q, and the machine difference correction amount at the rated point A and the machine difference correction amount at at least another correction point are stored. Alternatively, the present invention may be applied to a case in which a correction relating to a machine difference is performed on the fuel injection amount Q according to the engine operation. That is, since the fuel injection end timing (spill timing) θ and the injection amount Q have a 1: 1 relationship, any of them may be used.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a fuel injection control device for a diesel engine having an inner cam type fuel injection pump.

FIG. 2 is a perspective view showing a configuration of an inner cam pressure feeding portion.

FIG. 3 is a diagram showing a pulsar and a cam angle sensor.

FIG. 4 is a time chart for explaining an injection operation.

FIG. 5 is a view for explaining correction data stored in a ROM.

FIG. 6 is a flowchart showing a fuel injection control routine.

FIG. 7 is a configuration diagram of an inspection device.

FIG. 8 is a flowchart showing an inspection process.

FIG. 9 is an explanatory diagram showing a relationship between a difference between a maximum injection pressure and a correction amount.

FIG. 10 is a diagram showing a relationship between a pump maximum pressure and an engine output.

FIG. 11 is a diagram showing a relationship between a NO _x emission amount and a particulate emission amount.

FIG. 12 is a configuration diagram for measuring a pump maximum pressure.

FIG. 13 is a diagram showing a sensor output waveform for measuring a pump maximum pressure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel injection pump, 3 ... Drive shaft, 5 ... Low pressure side fuel chamber, 10 ... Plunger, 11 ... Pump chamber as fuel pressurization chamber, 22 ... Electromagnetic spill valve, 36 ... Pulser, 3
7 cam angle sensor, 38 ROM as storage means, 5
0: microcomputer as arithmetic means and determination means

Claims (2)

[Claims] 1. An electromagnetic spill valve for terminating fuel injection by communicating a fuel pressurizing chamber for pressurizing fuel by operation of a plunger according to a cam profile and a low-pressure side fuel chamber, and operating the plunger. A cam angle sensor that generates a signal for detecting the cam angle corresponding to the cam lift associated with the rotation of the drive shaft, and at the point of high speed and high load in relation to the rotation speed and the injection amount or the rotation speed and the fuel injection end timing Storage means for storing the machine difference correction amount and the machine difference correction amount at at least another correction point, and performing correction relating to the machine difference variation with respect to the fuel injection amount or the fuel injection end timing according to the engine operation, A device for inspecting a fuel injection pump comprising: a difference between the machine difference correction amount at the point of high speed and high load and the machine difference correction amount at the correction point or Calculating means for calculating the ratio; and determining means for determining that the maximum injection pressure of the pump is out of an allowable range when the difference or ratio of the machine difference correction amount by the calculating means is out of a predetermined range. An inspection device for a fuel injection pump. 2. The calculation means calculates a difference or a ratio between the machine difference correction amount at the point of high speed and high load and the machine difference correction amount at the low speed and low load correction point. Inspection apparatus for a fuel injection pump according to claim 1.