WO2013147078A1

WO2013147078A1 - Hydraulic-drive fuel injection device and internal combustion engine

Info

Publication number: WO2013147078A1
Application number: PCT/JP2013/059370
Authority: WO
Inventors: 昭仁青田; 浩二江戸
Original assignee: 三菱重工業株式会社
Priority date: 2012-03-30
Filing date: 2013-03-28
Publication date: 2013-10-03
Also published as: KR101623679B1; JP2013209948A; KR20140126768A; JP5881505B2; CN104169565B; CN104169565A

Abstract

The purpose of the present invention is to shorten heat receiving time that corresponds to a shortening in fuel injection time and to make a fuel injection pressure mode after a prescribed amount of time has passed since the start of fuel injection to become an injection mode with a high rate of increase in injection pressure. Provided are the following: a first electromagnetic valve (34) that controls the opening and closing of an open-side logic valve (31) that governs the supply of operating oil to a pressurization device (6) that increases operating oil pressure through a pressurization piston (22) and transmits such pressure to a plunger (4) of a fuel injection pump (1) and of an closed-side logic valve (32) that governs the discharge of operating oil from the pressurization device (6)respectively; a second electromagnetic valve (35) that controls the opening and closing of an open-side logic valve (71) that governs the supply of operating oil to the pressurization device (6); and a controller that controls the opening and closing of the electromagnetic valves (34, 35). The controller controls the opening and closing timing of the electromagnetic valves (34, 35) and adjusts the lift of the electromagnetic valves (34, 35) so that the injection pressure of the fuel injected from the fuel injection pump (1) reaches a desired fuel injection pressure.

Description

Hydraulic drive fuel injection device and internal combustion engine

The present invention relates to a hydraulically driven fuel injection device and an internal combustion engine that inject fuel into an internal combustion engine such as a diesel engine.

As a hydraulic drive fuel injection device which injects a fuel to internal combustion engines, such as a diesel engine, what was indicated by patent documents 1 is known, for example.

JP 2004-100644 A

In an internal combustion engine, it is generally required to shorten a heat receiving period to improve an in-cylinder combustion cycle, but a rapid increase in combustion temperature causes an increase in NOx (nitrogen oxide). Therefore, the fuel injection pressure mode after a certain period from the start of fuel injection becomes the injection pressure mode with a large injection pressure increase rate, that is, by setting it as a so-called high fuel injection pressure mode. It is said that fuel consumption is reduced as well as the increase is suppressed and NOx emissions are reduced.

On the other hand, in the one disclosed in the above-mentioned Patent Document 1, there is room for further shortening the heat receiving period (while shortening the period of the high fuel injection pressure mode) although it is in the high fuel injection pressure mode. There has been a need for further improvement of what has been disclosed in the above-mentioned Patent Document 1.

The present invention has been made in view of the above circumstances, and shortens the heat receiving period corresponding to the shortening of the fuel injection period, and the fuel injection pressure mode after a predetermined period from the start of fuel injection is the injection pressure increase rate. An object of the present invention is to provide a hydraulically driven fuel injection device and an internal combustion engine capable of being in a so-called high fuel injection pressure mode which is a large injection pressure mode.

The hydraulically-driven fuel injection system according to the present invention includes a pressure-increasing device for increasing the pressure of hydraulic fluid by a pressure-increasing piston and transmitting the pressure to a plunger of a fuel injection pump, and an open side logic that controls supply of hydraulic fluid to the pressure booster. A first solenoid valve for controlling the opening and closing of a valve and a closed side logic valve for controlling the discharge of hydraulic fluid from the pressure booster, and at least one open side logic valve for controlling the supply of hydraulic fluid to the pressure booster; A hydraulically driven fuel injection device comprising: at least one second solenoid valve for opening and closing control; and a controller for opening and closing control of the first solenoid valve and the second solenoid valve, the controller Controls the opening / closing timing of the first solenoid valve and the second solenoid valve, and adjusts the lift of the first solenoid valve and the second solenoid valve to control the fuel injection. Fuel injection pressure to be injected from the pump and reach the desired fuel injection pressure.

According to the hydraulically driven fuel injection device of the present invention, the fuel injection pressure injected from the fuel injection pump is reduced to a desired fuel injection pressure, that is, the heat reception period corresponding to the shortening of the fuel injection period and The fuel injection pressure mode after a predetermined period of time can be the injection pressure mode with a large injection pressure increase rate, that is, a so-called post-high fuel injection pressure mode.

In the above-described hydraulically driven fuel injection device, the diameters of the lift and the throttle of the first solenoid valve and / or the number of the second solenoid valve, the lift of the first solenoid valve and / or the second solenoid valve may be appropriately selected. A wide variety of fuel injection pressure modes may be created by selecting as needed.

According to such a hydraulic drive fuel injection device, it is possible to create a wide variety of fuel injection pressure modes by selecting the number of solenoid valves, lifts of solenoid valves, and diameters of throttles as needed. The degree of freedom in injection rate control can be expanded.

An internal combustion engine of the present invention comprises the above-described hydraulically driven fuel injection device.

According to the internal combustion engine of the present invention, the heat receiving period corresponding to the shortening of the fuel injection period is shortened, and the fuel injection pressure mode after a predetermined period from the start of the fuel injection becomes the injection pressure mode having a large injection pressure increase rate. It has a hydraulically driven fuel injection device capable of being in the so-called high fuel injection pressure mode. Therefore, it is possible to suppress the in-cylinder maximum pressure and the increase in combustion temperature, reduce the amount of NOx (nitrogen oxide) emissions, and reduce fuel consumption.

According to the hydraulically driven fuel injection device of the present invention, the heat reception period corresponding to the shortening of the fuel injection period is shortened, and the fuel injection pressure mode after a predetermined period from the start of fuel injection shows an injection pressure with a large injection pressure increase rate. It can be a so-called back high fuel injection pressure mode which becomes a mode.

It is a systematic diagram of a hydraulic drive fuel injection device concerning one embodiment of the present invention. FIG. 1 is a cross-sectional view of a fuel injection pump which is a component of a hydraulic pressure-driven fuel injection device according to an embodiment of the present invention. (A) is a chart showing the relationship between time and the lift of the open side logic valve (main valve) which is one component of the hydraulic drive fuel injection device according to one embodiment of the present invention, (b) is the present embodiment It is a graph which shows the relationship between the fuel injection pressure of the fuel injection pump which is one component of the hydraulic drive fuel injection system which concerns on these, and time. FIG. 1 is a cross-sectional view of an open side logic valve (main valve) which is a component of a hydraulic pressure-driven fuel injection device according to an embodiment of the present invention.

Hereinafter, a hydraulic pressure-driven fuel injection device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4.
FIG. 1 is a system diagram of a hydraulic drive fuel injection device according to the present embodiment, and FIG. 2 is a cross sectional view of a fuel injection pump which is one component of the hydraulic drive fuel injection device according to the present embodiment. FIG. 3 (a) is a chart showing the relationship between time and the lift of the open side logic valve (main valve) which is one component of the hydraulic drive fuel injection device according to the present embodiment, and FIG. 3 (b) is a diagram. It is a graph which shows the relationship between the fuel injection pressure of the fuel injection pump which is one component of the hydraulic-drive fuel-injection apparatus concerning this embodiment, and time. FIG. 4 is a cross-sectional view of an open side logic valve (main valve) which is a component of the hydraulically driven fuel injection device according to the present embodiment.

As shown in FIG. 2, the fuel injection pump 1 includes a pump case 2, a plunger barrel 3 fixed in the pump case 2, a plunger 4 slidably fitted in the plunger barrel 3, and a plunger A discharge valve 5 fixed to the top of the barrel 3 and a pressure booster 6 are provided. A plunger chamber 7 is defined by the inner peripheral surface of the plunger barrel 3 and the upper surface of the plunger 4.
Reference numeral 8 in FIG. 2 denotes a tappet connected to the lower part of the plunger 4, reference numeral 9 denotes a plunger spring for urging the plunger 4 in a direction to push down, and reference numeral 10 denotes a spring support for supporting the plunger spring 9. It is.

The pressure increasing device 6 includes a pressure increasing portion case 21 fixed to the lower portion of the pump case 2. In the pressure increasing portion case 21, two stepped pistons having different inner diameters, that is, a large cross-sectional area are provided. The large diameter piston 22 and the piston rod 23 integral with the large diameter piston 22 and smaller in diameter than this are fitted in a reciprocally slidable manner. The piston rod 23 is fixed to the large diameter piston 22, and the upper surface of the piston rod 23 is in contact with the lower surface of the tappet 8.
In addition, the code | symbol 24 in FIG. 2 is the small oil chamber which the piston rod 23 faces, and the small oil chamber 24 is always supplied with hydraulic fluid from the low voltage | pressure hydraulic fluid pump not shown via the low voltage | pressure hydraulic fluid pipe 60. .
Further, reference numeral 25 in FIG. 2 is a large oil chamber in which the large diameter piston 22 faces, and the hydraulic fluid is supplied and discharged by the two open

side logic valves

31, 71 and one close side logic valve 32. There is.

In FIG. 1,

reference numerals

31 and 71 denote open side logic valves (main valves) for controlling the supply of hydraulic oil to the large oil chamber 25 of the pressure booster 6, and reference numeral 32 denotes a large valve of the pressure booster 6. It is a closed side logic valve that controls the discharge of hydraulic fluid from the oil chamber 25. The outlet ports of the open

side logic valves

31 and 71 and the inlet port of the closed side logic valve 32 are connected to the large oil chamber 25 of the pressure booster 6 via the hydraulic oil pipe 33, respectively.
Reference numeral 34 is a (first) solenoid valve for opening and closing control of the opening side logic valve 31 and the closing side logic valve 32, and reference numeral 35 is a (second) solenoid valve for opening and closing control of the opening side logic valve 71. is there. The

solenoid valves

34 and 35 are each controlled to open and close by a controller (not shown).
Reference numeral 36 in FIG. 1 denotes a hydraulic oil pump for supplying hydraulic oil for controlling the start and end of fuel injection, and reference numeral 37 denotes a hydraulic oil supply pipe connected to the discharge port of the hydraulic oil pump 36. It is. Reference numeral 38 is an accumulator provided in the hydraulic oil supply pipe 37.
Further, reference numeral 39 in FIG. 1 denotes an oil tank, and reference numeral 40 denotes a hydraulic oil return pipe connected to the oil tank 39 from the outlet port of the closing side logic valve 32.

The hydraulic oil inlet ports of the open

side logic valves

31 and 71 are respectively connected to the hydraulic oil supply pipe 37, and the outlet port of the closed side logic valve 32 is connected to the oil tank 39 via the hydraulic oil return pipe 40 . Also, the back pressure port of the open side logic valve 31 is connected to the solenoid valve 34 via the back pressure pipe 41, and the back pressure port of the close side logic valve 32 is connected to the solenoid valve 34 via the back pressure pipe 42 The back pressure port of the open side logic valve 71 is connected to the solenoid valve 35 via the back pressure pipe 43.
The back pressure port of the closing logic valve 32 is always open to the side of the oil tank 39 by the solenoid valve 34 except during fuel injection.

Reference numeral 51 in FIG. 1 is a hydraulic oil pipe branched from the hydraulic oil supply pipe 37 and connected to the inlet port of the solenoid valve 34, and reference numeral 52 is a branch from the hydraulic oil supply pipe 37 and inlet of the solenoid valve 35. It is a hydraulic oil pipe connected to the port. The code | symbol 53 is a throttle provided in the middle of the hydraulic fluid pipe 51, and the code | symbol 54 is a throttle provided in the hydraulic fluid pipe 52 in the middle.
Further, reference numeral 55 in FIG. 1 denotes a back pressure return pipe connected to the hydraulic fluid return pipe 40 from the closing side logic valve return port of the solenoid valve 34 and the closing side logic valve return port of the solenoid valve 35. Reference numeral 56 denotes a throttle provided in the middle of the back pressure return pipe 15 extending from the close side logic valve return port of the solenoid valve 34 to the hydraulic fluid return pipe 40. Reference numeral 57 denotes a throttle provided in the middle of the back pressure return pipe 15 extending from the close side logic valve return port of the solenoid valve 35 to the hydraulic fluid return pipe 40.

Reference numeral 58 in FIG. 1 is connected from the open side logic valve return port of the solenoid valve 34 to the hydraulic fluid return pipe 40 to the oil tank 39 via the back pressure return pipe 55 (or directly operated from the return port) Reference numeral 59 denotes a throttling provided in the middle of the escape oil passage.

During operation of a diesel engine equipped with such a hydraulically driven fuel injection device 81, a hydraulic oil pipe is connected to the back pressure port of the open side logic valve 31 via the back pressure pipe 41 during a period in which fuel injection is not performed. The hydraulic pressure controlled at the flow rate is applied by the throttle 53 provided at 51, and the flow rate is controlled by the throttle 54 provided at the hydraulic fluid pipe 52 via the back pressure pipe 43 at the back pressure port of the open side logic valve 71 Applied hydraulic pressure is applied. Further, the back pressure port of the closing side logic valve 32 is opened to the back pressure side return pipe 55 whose flow rate is controlled by the throttle 56.
On the other hand, at the start of fuel injection, the back pressure port of the open side logic valve 31 is opened by the solenoid valve 34, and the back pressure port of the close side logic valve 32 which is always open is closed. The back pressure port of the open logic valve 71 is opened by the valve 35.

Thereby, the inlet port and the outlet port of the open side logic valve 31 are communicated, the inlet port and the return port of the closed side logic valve 32 are shut off, and the hydraulic oil from the hydraulic oil pump 36 is supplied to the hydraulic oil supply pipe. 37 is supplied to the large oil chamber 25 of the pressure increasing device 6 through the opening side logic valve 31 and the hydraulic oil pipe 33, and after a predetermined time, the inlet port and the outlet port of the opening side logic valve 71 are communicated and operated The hydraulic oil from the oil pump 36 is supplied from the hydraulic oil supply pipe 37 to the large oil chamber 25 of the pressure intensifier 6 through the open side logic valve 71 and the hydraulic oil pipe 33.
When the hydraulic oil is introduced into the large oil chamber 25, the operation supplied to the large oil chamber 25 due to the difference in sectional area between the large oil chamber 25 and the small oil chamber 24, that is, the sectional area difference between the large diameter piston 22 and the plunger 4 Increase the pressure of the oil.

Then, as shown in FIG. 2, the hydraulic pressure in the large oil chamber 25 pushes up the plunger 4 against the spring force of the plunger spring 9 via the piston rod 23 and the tappet 8 so that the fuel in the plunger chamber 7 is pressurized. The pressure is increased and pressure-fed to a fuel injection valve (not shown) via the discharge valve 5 to start fuel injection.

Thus, by opening the open logic valve 31 first and then opening the open logic valve 71, the fuel injection pressure (fuel injection rate) in the first half of the fuel injection period per injection stroke Is reduced, and the fuel injection pressure in the second half is increased (Fig. 3 (shows the opening and closing states of the open

side logic valve

31, 71 per lift stroke (lift vs. time) and changes in fuel injection pressure). a) and as shown in FIG. 3 (b)).

At the end of the injection, the back pressure port of the open side logic valve 31 is closed by the solenoid valve 34, the back pressure port of the close side logic valve 32 is opened, and the back pressure port of the open side logic valve 71 is opened by the solenoid valve 35. It is closed.
Thereby, the hydraulic oil inlet port and the outlet port of the open side logic valve 31 are shut off, and the hydraulic oil inlet port and the outlet port of the open side logic valve 71 are shut off. The hydraulic fluid in the large oil chamber 25 of the pressure booster 6 communicates with the return port, and the hydraulic fluid in the large oil chamber 25 of the pressure booster 6 is oil via the back pressure return pipe 55 and the hydraulic oil return pipe 40 whose flow rate is regulated by the throttle 56. It is returned to the tank 39.
When the hydraulic oil is discharged from the large oil chamber 25, the plunger 4 is lowered by the spring force of the plunger spring 9 and the hydraulic pressure of the low pressure hydraulic oil introduced to the small oil chamber 24 via the low pressure hydraulic oil pipe 60.

Here, the lifts of the open

side logic valves

31, 71 shown in FIG. 3A are provided at one end of a valve body 92 fitted so as to be reciprocably slidable in the valve casing 91 shown in FIG. The stroke (moving range) S of the piston 93 integrally formed with the body 92 is adjusted (increased or decreased) by changing the thickness (height) of the stroke adjusting piece 94 that adjusts (increases or decreases) S.
As shown in FIG. 3, the lift of the open side logic valve 31 is smaller than the lift of the open side logic valve 71, that is, the thickness of the stroke adjustment piece 94 of the open side logic valve 31 is the open side logic valve It is set to be thicker than the thickness of the stroke adjustment piece 94 of FIG.

Further, the inclination when the open side logic valve 31 shown in FIG. 3A is opened is determined by the throttle 59, and the inclination when the open side logic valve 71 shown in FIG. On the other hand, the inclination when the open side logic valve 31 shown in FIG. 3A is closed is determined by the aperture 53, and the inclination when the open side logic valve 71 shown in FIG. 3A is closed is determined by the aperture 54.
In addition, the code | symbol 95 in FIG. 4 is a spring which biases the valve body 92 and the piston 93 in the closing direction.

According to the hydraulically driven fuel injection device 81 according to the present embodiment, the fuel injection pressure injected from the fuel injection pump 1 is shortened to a desired fuel injection pressure, that is, a heat receiving period corresponding to shortening of the fuel injection period. At the same time, the fuel injection pressure mode after a predetermined period from the start of fuel injection can be the injection pressure mode with a large injection pressure increase rate, that is, the so-called high fuel injection pressure mode.

Further, according to the internal combustion engine equipped with the hydraulically driven fuel injection device 81 according to the present embodiment, the heat reception period corresponding to the shortening of the fuel injection period is shortened, and the fuel injection pressure after a predetermined period from the fuel injection start The mode can be a so-called post-high fuel injection pressure mode in which the injection pressure mode has a large injection pressure increase rate. Therefore, it is possible to suppress the in-cylinder maximum pressure and the increase in combustion temperature, reduce the amount of NOx (nitrogen oxide) emissions, and reduce fuel consumption.

The present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the scope of the present invention.
For example, various types of fuel injection pressure modes can be created by selecting the number of solenoid valves, lift of solenoid valves, and diameter of throttle as needed, and the degree of freedom of fuel injection rate control can be expanded. it can.

1 fuel injection pump 4 plunger 6 pressure booster 22 large diameter piston (pressure booster piston)
31 opening side logic valve 32 closing side logic valve 34 (first) solenoid valve 35 (second) solenoid valve 71 opening side logic valve

Claims

A pressure increasing device for increasing the pressure of hydraulic fluid by a pressure increasing piston and transmitting the pressure to a plunger of a fuel injection pump;
An open side logic valve that controls supply of hydraulic fluid to the pressure intensifier, and a first solenoid valve that opens and closes a closed side logic valve that controls discharge of hydraulic fluid from the pressure intensifier;
At least one second solenoid valve that opens and controls at least one open side logic valve that controls supply of hydraulic fluid to the pressure intensifier;
And a controller for controlling the opening and closing of the first solenoid valve and the second solenoid valve, respectively.
The controller controls the opening / closing timing of the first solenoid valve and the second solenoid valve, and adjusts the lift of the first solenoid valve and the second solenoid valve to thereby control the fuel injection pump. A hydraulically driven fuel injection system in which the fuel injection pressure injected from the fuel injection pressure is set to a desired fuel injection pressure.
By selecting the number of the first solenoid valve and / or the second solenoid valve, the lift of the first solenoid valve and / or the second solenoid valve, and the diameter of the throttle as needed, The hydraulically powered fuel injector according to claim 1, wherein a wide variety of fuel injection pressure modes are created.
An internal combustion engine comprising the hydraulically driven fuel injection device according to claim 1.