JPS59103958A - Distribution type fuel injection pump - Google Patents

Abstract

PURPOSE:To easily control an injection time and an injection amount, by adjusting the flow of high pressure fuel from a distribution pump chamber to a low pressure section. CONSTITUTION:When a timing electromagnetic valve 30 is opened so that fuel is injected by a controller 1 at the optimum time of an engine, communication between a timing passage 8 and a feed passage 9 is shut off, the fuel in a distribution pump chamber 26 starts to be compressed into a high pressure, and with a feed check valve 32 closed, the fuel is forcibly fed from a discharge valve 24 to inject it through a nozzle. After injection continues only during a time for which an optimum injection amount is obtained according to the load of an engine, the electromagnetic valve 3 is opened to intercommunicate a spill passage 5 and a drain passage 42, and the high pressure fuel in the distribution pump chamber 26 is discharged to a tank 52 through a control port 6, the spill passage 5, and a drain passage 42.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a distribution type fuel injection pump suitable for use in controlling fuel injection timing, fuel injection amount, cylinder reduction operation, etc. for an internal combustion engine.

In conventional distribution-type fuel injection pumps, the injection timing was controlled by the position where the face cam rode on the cam roller, and the injection amount was controlled by the spill ring position.

However, a large force is required to rotate the cam roller, a complicated governor mechanism is required to control the spill ring position, and the cam is lubricated with fuel, so high fuel injection pressure is required. The drawback was that it couldn't be done.

An object of the present invention is to provide a device that can easily control injection timing and injection amount.

The present invention will be explained below based on examples.

The embodiment shown in FIGS. 1 to 4 will be described. In addition, the first
In the figure, a 90° exploded view of the feed pump 13 is shown superimposed to make the structure of the feed pump 13 easier to understand.

+i[ is rotationally driven by a feed pump 13, a cam plate 16, and a distribution plunger 12 in conjunction with a drive shaft 20 driven by an engine (not shown).

The dispensing plunger 12 is slidably fitted into the dispensing cylinder 11 , and the dispensing pump chamber 26 formed by the dispensing cylinder 11 and the dispensing plunger 12 includes the dispensing cylinder 11 .
A control boat 6 formed within the dispensing plunger 12 communicates with a communication passage 12 formed within the dispensing plunger 12. Control boat 6 is in communication with spill solenoid valve 3 via spill passage 5 and with timing solenoid valve 30 via timing passage 8 . In addition, the communication path 21 includes a discharge boat 22 and a distribution path 2.
3. Connected to a nozzle (not shown) via the discharge valve 24,
It is also connected to a feed pump 13 via a feed boat 10, a feed check valve 32, a feed passage 9, and a pressure regulating valve 14, which are integrally formed in the housing 7. Oil is supplied to the oil chamber 4 of the housing 7 by an oil pump 31 of the engine. Further, the rotation speed detector 2 is set close to the timing gear 15, and sends the rotation speed NE to the controller 1 together with information from the detector such as the accelerator position, temperature of each part, pressure, etc.

Next, the operation will be explained. First, timing solenoid valve 30
is energized, and the timing passage 8 and the feed passage 9 are in communication. The spill solenoid valve 3 is also energized, and the spill passage 5 and drain passage 42 are cut off. At this time, the face cam 17 formed on the cam plate 16
is in a state where it has not yet run onto the cam roller 18. The feed pump 13 connects the tank 52 to the feed passage 5.
The fuel is sucked up through 0 and supplied under pressure, and the pressure is set to a predetermined pressure by the pressure regulating valve 14. 6 to supply fuel to the distribution pump chamber 26.

The engine rotates to rotate the drive shaft 20,
When the face cam 17 rides on the cam roller 18, the distribution plunger 12 is rotated and driven in its axial direction. The discharge boat 22 and the distribution passage 23 communicate with each other, making it possible to forcefully feed the fuel in the distribution pump chamber 26 and send the fuel to the nozzle. However, since the timing solenoid valve 30 is energized, the timing boat 8 and the feed passage 9 are in communication and the fuel in the distribution pump chamber 26 is discharged from the control boat 6, so the pressure is not high and the fuel is not injected from the nozzle.

When the controller 1 de-energizes the timing solenoid valve 30 and closes the solenoid valve 30 so that fuel is injected at the optimum timing for the engine, the communication between the timing passage 8 and the feed passage 9 is cut off, and the distribution pump chamber The fuel in 26 begins to be compressed to a high pressure, and the feed check valve 32 closes to forcefully feed the fuel from the discharge valve 24 and inject it from the nozzle. After continuing the injection for a period of time to obtain the optimum injection amount depending on the engine load, etc., the controller 1 stops energizing the spill solenoid valve 3, and the solenoid valve 3 is opened to open the spill passage 5 and the drain passage 42. The high-pressure fuel in the distribution pump chamber 26 is discharged to the tank 52 via the control boat 6, the spill passage 5, and the drain passage 42. The dispensing plunger is driven a little further until it reaches top dead center and then begins to descend. The feed check valve 32 opens and the distribution pump chamber 26 is filled with fuel again, and the distribution plunger 12 reaches the bottom dead center and stops driving in the axial direction, but continues to rotate and starts moving in the next cylinder. A discharge boat 22 communicates with the distribution passage (not shown) and repeats the operations described above.

In the distribution type injection pump having this configuration, reduced-cylinder operation is also possible, and this can be carried out as follows. reduced cylinder,
That is, during the pressure feeding stroke of the distribution plunger 12 of the cylinder in which fuel is not injected, the timing solenoid valve 30 is energized and kept open, or the spill solenoid valve 3 is not energized and kept open. Capable of reduced cylinder operation.

Next, how the two solenoid valves 30.3 are controlled will be explained with reference to FIGS. 2-4. First, the timing electromagnetic valve 30 is controlled by interpolation based on the engine speed NE and injection amount Q as shown in FIG. 2 using a stored two-dimensional map showing the injection timing. In other words, as shown in Figures 3 and 4, the engine operating state (engine speed NE, etc.) and the accelerator position are detected by the engine speed detector 2, etc., and the valve closing time TQ of the spill solenoid valve 3 and the vehicle's running state are detected. Read the state (vehicle speed V, etc.), interpolate the injection timing Tb from Fig. 2, and then command the corrected timing 'I''b by adding a judgment as to whether or not to perform reduced-cylinder operation based on the vehicle running condition. According to this command value Tb, the timing solenoid valve 3 is adjusted for the valve opening time.
Current is output so that valve 0 opens. Actual injection timing'l
``b'' is fed by a nozzle needle valve lift sensor, etc. Also, the valve opening timing TQ' of the spill solenoid valve 3 is also fed back to correct the command value and achieve the target ``rb''.
Repeat this action until you reach .

Next is the control of the spill solenoid valve 3, but in the same way the rotation speed NE
The required injection amount Qo is calculated by reading the accelerator position, injection timing command value 'b, driving conditions, etc., and then the QO is corrected according to the driving conditions (increase amount ΔQc during cylinder reduction operation, etc.) (i.e., Q = QO + Qc). ), which indicates the memorized N
From the two-dimensional map of E and Q, when the spill solenoid valve 3 is required to close, 11JI ``I' Q.

is interpolated and corrected by the injection timing Tb (i.e., T
Q = T Q o + T b), and the opening timing T Q o of the spill solenoid valve 3 is output.

Similarly, Tb' and TQ' are fed back, engine speed NE, accelerator position, etc. are read again, and this is repeated until the target TQ is achieved. In the high speed range, the timing solenoid valve 3o remains closed (that is, in the most advanced state) and the injection amount Q is controlled by the opening/closing valve of the spill solenoid valve 3, and the timing solenoid valve 30 also controls the injection path. By controlling the injection by dividing the number of cylinders into two using 21[1 solenoid valves, the responsiveness of the solenoid valves and power consumption can be reduced.

Since oil is used for the lubricant d1 of the cam roller 18 and the face cam 17, oil lubrication is possible and high-pressure injection is also possible.

Although two solenoid valves are used in this embodiment, it is of course possible to use only one solenoid valve.

AC: As described in detail above, the present invention includes a control boat opening into the distribution pump chamber, a solenoid valve provided in the middle of a passage communicating between the control boat and the low pressure section, and the solenoid valve. The controller drives a solenoid valve to adjust the flow of high-pressure fuel from the distribution pump chamber to the low-pressure section, and controls the fuel injection timing and fuel injection amount. The fuel injection amount can be easily and precisely controlled with a simple mechanism, and the face cam, cam roller, etc. formed on the cam plate can be lubricated with oil, which has the effect of enabling high-pressure injection.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the overall configuration of an embodiment of the present invention, and FIG.
The figure is a perspective view showing a two-dimensional map of fuel injection timing control, Figure 3 is a block diagram of the system, and Figure 4 is a part of a flowchart in the calculation section. (al is the target value of the timing solenoid valve. '1b shows the calculation, (bl shows the calculation of the target value 'rQ of the injection quantity solenoid valve. 1... Controller, 3.30... Spill solenoid valve forming the solenoid valve, timing solenoid valve, 5,8.9゜42
... Spill passage, timing passage, feed passage, drain passage forming a passage communicating between the control boat and the low pressure section, 6... Control boat, 11... Distribution cylinder, 12... Distribution plunger, 2G...Distribution pump room. (a) Figure 4 (b)

Claims (1)

[Claims] The distribution plunger is oil-tightly fitted into the distribution cylinder and the distribution plunger is rotated and reciprocated within the distribution cylinder to pressurize the fuel in the distribution pump chamber formed by the distribution cylinder and the distribution plunger and supply fuel to each cylinder. In a distribution type fuel injection pump that performs distributed pressure feeding, a control boat opening in the distribution pump chamber, a solenoid valve provided in the middle of a passage communicating between the control port and a low pressure section, and an opening/closing signal to the solenoid valve are provided. A distribution type fuel injection pump characterized in that the controller drives a solenoid valve to adjust the flow of high pressure fuel from the distribution pump chamber to the low pressure section and control the fuel injection timing and fuel injection amount. .