JPH03141844A - Fuel injection device - Google Patents

Abstract

PURPOSE:To inject the accurate fuel quantity into combustion chambers from injection nozzles by providing a solenoid valve control means for controlling solenoid valves taking account of position difference between pumps due to the torsion of a driving mechanism, thereby correcting the phase difference of each pump. CONSTITUTION:A phase detecting means is formed of can angle sensors 52, 54 disposed facing the protrusions 511-516, 531-536 of rotary discs 51, 53 and a cylinder discriminating sensor 62 disposed facing the protrusion 611 of a rotary disc 61. A phase difference operating means, a correction value operating means and a solenoid valve control means are formed of programs memorized in a memory in an electronic control unit 11. The correction valve operating means computes the correction value of timing on the basis of the phase and the phase difference detected by the phase detecting means, and the solenoid valve control means controls solenoid valves 46a-46f on the basis of the correction value computed pump by pump by the correction value operating means. The accurate fuel quantity can be thereby injected into the combustion chamber of each cylinder from injection nozzles 17a-17f.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a fuel injection device that corrects fuel injection amount in an internal combustion engine.

[Prior art]

Conventionally, the pressure feeding mechanism in the injection pump of a fuel injection device is
As disclosed in Japanese Patent Application Laid-Open No. 59-147836 "Fuel Injection Control Device for Internal Combustion Engine", by the operation of a solenoid valve disposed between the high pressure chamber and the low pressure chamber of the injection pump,
It is a time-controlled type that controls the injection amount and injection timing.

[Problem to be solved by the invention]

By the way, in a pressure feeding mechanism using a square-type injection pump or a unit injector as a fuel injection device, a plunger is reciprocated by a camshaft that is linked to the crankshaft of an internal combustion engine and has a cam corresponding to each cylinder. It is conceivable to use a time-controlled system in which the injection amount and injection timing are controlled by the operation of electromagnetic valves disposed in each cylinder. For example, in a time-controlled format injection pump, the angle determined geometrically from a certain reference point is converted into time to operate the solenoid valve of each cylinder of the format injection pump, so each cylinder is pressed. It is not possible to compensate for variations in the pumping timing of each cylinder caused by the torsion of the camshaft that reciprocates. Therefore, compared to a size-type injection pump in which the pumping stroke is mechanically determined, there is a problem in that the variation in injection amount between cylinders is rather large. The present invention was developed to solve the above problems, and its purpose is to obtain the phase angle of each cylinder due to the twist of the camshaft, and to calculate the difference in injection timing with respect to the pumping stroke of each cylinder. It is an object of the present invention to provide a fuel injection device that can feed back and correct the command time to a solenoid valve. C Means for Solving the Problems] The structure of the invention for solving the above problems is such that the fuel flowing from the fuel supply source is pressurized by being pressed and reciprocated by a drive mechanism interlocked with the crankshaft of the internal combustion engine. In a fuel injection device having a plurality of pumps corresponding to injection nozzles of the combustion chamber, in order to inject the fuel from the injection nozzle into the combustion chamber of the internal combustion engine when the pressure exceeds a predetermined pressure, detecting the phase at a predetermined position of the drive mechanism. and a discharge gear connected to the pump, and controls the timing at which fuel is pumped from the pump to the injection nozzle by a closing operation or when fuel is transferred from the pump to the injection nozzle by an opening operation. a solenoid valve, a phase difference calculation means for calculating a phase difference due to the torsion of the drive wJ mechanism according to the position of the pump, and correction of the timing based on the phase detected by the phase detection means and the phase difference. The present invention is characterized by comprising a correction value calculation means for calculating a value, and a solenoid valve control means for controlling the electromagnetic valve based on the correction value calculated by the correction value calculation means for each pump.

[Effect]

The phase detection means detects the phase at a predetermined position of the drive mechanism. Further, the electromagnetic valve is disposed between the discharge gears connected to the pump, and when the solenoid valve is closed, fuel is forcefully delivered from the pump to the injection nozzle, and when the solenoid valve is opened, the timing at which fuel is leaked from the pump is controlled. Further, the phase difference calculating means calculates a phase difference due to the twisting of the drive mechanism according to the position of the pump. Then, the correction value calculation means calculates the correction value of the timing corresponding to the time delay for each pump based on the phase detected by the phase detection means and the phase difference due to the torsion of the drive mechanism. Since the solenoid valve is controlled by the solenoid valve control means based on the correction value calculated by the correction value calculation means, an accurate amount of fuel is supplied to each injection nozzle in the combustion chamber of each cylinder of the internal combustion engine. It will be sprayed from.

【Example】

The present invention will be described below based on specific examples. FIG. 1 is a configuration diagram showing a fuel injection device using a six-cylinder in-line injection pump according to the present invention. In FIG. 1, a portion surrounded by a dashed line indicates an injection pump 20 of a six-cylinder in-line type. The injection pump 20 includes a camshaft 21 as a pump drive shaft that rotates at a speed of 172 engine revolutions. Six cams 22a to 22f are integrally formed on the camshaft 21, and each cam 22a to 22f is connected to a plunger 31a to 31a through a foa 32a to 32f.
1f is pressed downward in the figure by springs 38a to 38f. Plungers 31a-31f are plunger barrels 41a-
41f in an oil-tight manner, and the plungers 31a to 3
Pump chambers 40a-40f are created between the top of 1f and plunger barrels 41a-41f. The pump chambers 40a to 40f pass through check valves 45a to 45f,
It is connected to the injection nozzles 17a to 17'' of each cylinder.The plunger barrels 41a to 41f have feed holes 4
2a to 42f are arranged. These feed holes 42a to 42f are provided with a low pressure supply pump 1 from the tank 18.
9 is connected to a low pressure fuel gear gallery 49 filled with fuel fed at a constant low pressure. In addition, the pump chambers 40a to 40f further include a spill passage 4.
3a to 43f are arranged. Those spill passages 43
Solenoid valves 46a to 46'' for performing spill control are disposed in correspondence with each cylinder in the middle of the exhaust gears 48a to 48f, which are passages from a to 43f to the low pressure fuel gear gallery 49. The exhaust galleys IJ 48a to 48f are configured to be closed only while the solenoid valves 46a to 46f are energized.In order to control the solenoid valves 46a to 46f, a carrot is installed coaxially with the camshaft 21. In accordance with the number of cylinders, in this embodiment, rotating disks 51 and 5 having protrusions at six locations are used.
3 is on the 1st cylinder side (drive side) and 6th cylinder side,
They are installed so that they are statically in phase. Cam angle sensors 52 and 54, which are known electromagnetic pickups, are arranged opposite to these six protrusions. A signal is output to the electronic control unit (ECU) 11 each time the protrusions 511 to 516 and 531 to 536 of the rotating disks 51 and 53 pass near the cam angle sensors 52 and 54. Here, the mounting phase of the rotating disks 51 and 53 is the cam 22.
It is determined that the cam angle sensors 52 and 54 are approached at rotational phases near the bottom dead center of each of a to 22f. Further, a rotating disk 61 is coaxially disposed on the camshaft 21, and a projection 611 is formed at one location on the outer periphery of the rotating disk 61. The protrusion 6 of the rotating disk 61
A cylinder discrimination sensor 62 is provided corresponding to the cylinder number 11. A signal is output from the cylinder discrimination sensor 62 to the electronic control device 11 every time the rotating disk 61 rotates once. Therefore, from the signals from the cam angle sensors 52, 54 and the cylinder discrimination sensor 62, the electronic control device 11 can accurately discriminate and capture the bottom dead center signal of a specific cylinder. Further, the plungers 31a to 31f are provided with a camshaft 2.
At the end of the pressure feeding step 1, the feed holes 42a~
Spill grooves 33a to 33'' are formed which coincide with the pump chambers 42f.Furthermore, the pump chambers 40a to 40f and the spill grooves 33a to 33f are constantly in communication through communication holes 34a to 34f. , the camshaft 21, the rotating disk 5
1, 53, rotating disk 61, etc. are shown rotated by 90" for convenience. In this embodiment, the phase detection means is a rotating disk !51.53
Cam angle sensors 52 and 54 arranged opposite to the protrusions of
and a cylinder discrimination sensor 62 disposed facing the protrusion of the rotating disk 61. Further, the phase difference calculation means, the correction value calculation means, and the electromagnetic valve control means are achieved by a program stored in a memory in the electronic control device 11. Next, the operation of the fuel injection device according to the present invention will be explained based on the time chart of FIG. 2 and with reference to the above-mentioned FIG. 1 and FIG. 3 showing the method of calculating the correction value. FIGS. 2(a) to 2(i) show each time chart of the operating state of the injection pump 20 of the fuel injection device of this embodiment during approximately one rotation, that is, during approximately 360° rotation of the camshaft 21. . Note that for the sake of simplicity, only the first cylinder and the sixth cylinder are illustrated. FIG. 2(a) shows the signal of the cylinder discrimination sensor 62 in FIG. 1, and FIG. The cam phase (for example, near bottom dead center) can be known. In addition, Fig. 2 (C) and Fig. 2 (0 indicate the first cylinder and the sixth cylinder, respectively)
It shows the cylinder cam lift. The one-dot chain line (1) in the time chart for the cam lift of the first cylinder shown in FIG. Dashed line (I
T) indicates a spill timing line where the spill groove 33a matches the feed hole 42a. 2(d) and 2(g) show the solenoid valve 46 of FIG.
The control timings of a and 46f are shown. The electronic control device 12 starts energizing (i.e., closes the valves) after a time TTh corresponding to the required injection start timing, which will be described later, from the cam angle signal corresponding to the solenoid valves 46a to 46f of the cylinders that will next undergo the pressure feeding process, Time T commensurate with the required injection amount of the system
After , energization is terminated (that is, the valve is opened). Therefore, for example, the pressure feeding stroke of the first cylinder of the injection pump 20 is set from after the timing (I) in FIG. 2(C) to before the timing (n), and
) is determined by spill control that starts when the solenoid valve 46a is closed and ends when the solenoid valve 46a opens, using the solenoid valve (first cylinder) control signal. Therefore, an amount of fuel corresponding to the shaded area in FIG. 2(C) is injected from the injection nozzle 17a into the engine cylinder. Here, the time T Tfi is a value determined by the operating state of the engine. And plungers 31a to 31
The downward load when pumping f, that is, the plunger 31a~
There is no twisting of the camshaft 21 due to the reaction force of 31f,
If there is no phase difference in the cam lift of each cylinder, the time T
TTl has the same value for each cylinder. However, during actual driving, the above-mentioned blanket 31a~
The reaction force 31f causes the camshaft 21 to twist. Therefore, in the sixth cylinder, since it is farthest from the drive side, the twist of the camshaft 21 is large, and if the solenoid valve 46f is closed at the same timing as the first cylinder, the cam lift usage range will be different. Plunger 31
Since the pumping stroke of f changes, the injection amount decreases (Fig. 2 (f), (g), (h), (i)
)reference). Therefore, the injection amount is corrected as follows. Cam angle sensor 5 installed on the 1st cylinder side and 6th cylinder side
1.53, find the phase difference ΔTa between the two. Then,
The phase difference between the second to fifth cylinders is the phase difference of the first cylinder △TTI
(=0) and the phase difference ΔTts between the 6th cylinder, if the cams 22a to 22f are arranged at equal intervals on the camshaft 21 as shown in FIG. demand. That is, From the phase difference ΔT Tn obtained in this way, the correction value, ie, time T? , is determined by the following formula. Tyn=T7++ΔTfn (n=1
．． 2.3.4.5.6) And the determined time TT,
, the opening/closing timing of the electromagnetic valves 46a to 46f is controlled to correct the injection amount. In the embodiment described above, two of the cam angle sensors 5254
However, as only the cam angle sensor 52 is used, the cam angle sensor 52 is used to determine the phase difference between the two and calculate a correction value according to the position of each cylinder of the injection pump 20. It is possible to measure the torsion of the shaft 21 and map the relationship therebetween. That is, the torsion of the camshaft 21 is caused by the drive reaction force during pressure feeding by the plunger, and the amount of torsion is determined by the engine rotation speed (= twice the injection pump rotation speed) and the injection amount (-accelerator opening). Ru. Therefore, it is also possible to experimentally measure the phase difference for each cylinder using the engine speed and the accelerator opening as parameters, create a map, store it in advance, and calculate the correction value. Further, the present invention provides direct 1'l rt at the cams 22a to 22''.
Needless to say, the present invention can also be applied to a unit injector.

【Effect of the invention】

The present invention is equipped with a solenoid valve control means that controls the solenoid valve by taking into account the phase difference between the pumps due to the torsion of the drive mechanism, so that the phase difference due to the torsion of the drive mechanism is corrected for each pump, and the internal combustion engine A precise amount of fuel is injected into the combustion chamber through an injection nozzle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram showing a fuel injection device according to a specific embodiment of the present invention. FIG. 2 is a time chart illustrating the operation of the fuel injection device according to the same embodiment. FIG. 3 is an explanatory diagram showing a method of calculating a correction value according to the same embodiment. 1 7 1 1 0 1 6 8 51゜52゜2 Electronic control unit (ECU) a~17''-Injection nozzle 20 Camshaft 22a~22f a~31f ・Plunger a~40f ・Pump chamber a~41f Pub plunger barrel a~46f°--Solenoid valve a~48f°Exhaust gear 53.61°'-Rotating disk 54-Cam angle sensor Cylinder discrimination sensor Injection pump cam 3rd ring

Claims (1)

[Scope of Claims] Pressurized by a drive mechanism linked to the crankshaft of the internal combustion engine to reciprocate, fuel flowing from the fuel supply source is pressurized and when the pressure reaches a predetermined pressure or higher, the fuel is injected into the combustion chamber of the internal combustion engine. A fuel injection device having a plurality of pumps corresponding to injection nozzles of the combustion chamber for injecting from the nozzles, comprising: a phase detection means for detecting a phase at a predetermined position of the drive mechanism; and a discharge gallery connected to the pumps. an electromagnetic valve disposed in the pump, which controls the timing of pressurizing the fuel from the pump to the injection nozzle by a closing operation or leaking fuel from the pump by an opening operation; and a torsion of the drive mechanism depending on the position of the pump. a phase difference calculation means for calculating a phase difference; a correction value calculation means for calculating a correction value for the timing based on the phase detected by the phase detection means and the phase difference; and a correction value calculation means for calculating the correction value for each pump. A fuel injection device comprising: solenoid valve control means for controlling the solenoid valve based on the correction value calculated by the means.