JPH05332217A - Hydraulic drive type water injector - Google Patents

Abstract

PURPOSE:To enable a constant amount of water to be discharged for a long period of time by a hydraulic drive type water injector applied to a water distributer of a diesel engine using a water injection fuel valve in which a discharge spool is driven by oil pressure so that water in a water chamber is pressurized to be discharged. CONSTITUTION:While a discharge spool 1 is inserted in a cylinder 3, a spool stopper 4 is fixed movably axially of the cylinder 3 to determine the stroke volume of the discharge spool 1. While an oil chamber 11 partitioned by the discharge spool 1 in the cylinder 3 is connected through a solenoid valve 7 to the discharge side of a high pressure oil pump 12, a water chamber at the opposite side to the oil chamber 11 is connected through a feed water check valve 5 to a water pump 13 and through a discharge check valve 6 to a fuel valve respectively. After the solenoid valve 7 is disposed at the discharge side to send low pressure water to the water chamber 10 by the water pump 13, the discharge spool 1 is moved left by pressurized oil with the solenoid valve 7 being disposed at the discharge side so that water in the water chamber 10 is pressurized to be discharged through the discharge check valve 6 to the fuel valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The hydraulically driven water injector of the present invention relates to a water injector applied to a water distribution device of a diesel engine using a water injection fuel valve.

[0002]

2. Description of the Related Art Conventionally, there is no hydraulic drive type water injector.

[0003]

Problems to be solved by the invention will be described with reference to FIGS. Figure 2 shows the outline of the water injection system of a water injection diesel engine. The spool valve system is shown in FIG. In FIG. 2, 14 is an engine crankshaft, and 15 is a fuel valve, which is provided on the cylinder head of the engine. 16 is a high-pressure water pump. Reference numeral 17 denotes a water distributor, which distributes high-pressure water to each fuel valve 15 in synchronization with the engine crankshaft 14. Reference numeral 18 denotes a water shutoff alarm provided on the water supply pipe of each fuel valve. Reference numeral 19 is an abnormality diagnosis device to which a water shutoff alarm 18 is connected. A fuel injection pump 20 is connected to the fuel valve 15. Reference numeral 21 is a rack limiter provided on the fuel injection pump 20. The effect of the system has been described in Japanese Patent Application No. 03-207147. The water distributor (water injector) of this system must always supply a constant amount of high pressure water to the fuel valve of the cylinder. FIG. 3 is a diagram of the spool valve system. In FIG. 3, 3 is a cylinder, 0
The reference numeral 1 designates a discharge spool whose sliding surface is chrome-plated or WC-sprayed and fitted in the cylinder 3 so as to be movable in the axial direction. A spool stopper 4 is provided on the cylinder 3 and is fixed so that its position can be adjusted. A pump chamber 010 is one of the chambers partitioned by the discharge spool 01 of the cylinder 3 and is a side where the spool stopper 4 is provided. 011 is a source chamber, which is a chamber on the side opposite to the pump chamber 010 partitioned by the discharge spool 01 of the cylinder 3. A fuel valve 15 is attached to a cylinder head of an engine (not shown). A solenoid valve 07 is provided between the cylinder 3 and the high pressure water / fuel valve 15. Next, the operation of the discharge spool system will be described.

When the solenoid valve 07 is on the suction side, the source drive chamber 011
Is connected to a drain pipe, the pump chamber 010 is connected to a high-pressure water pipe, high-pressure water flows into the pump chamber 010, and the discharge spool 0
1 is moved to the right to fill the pump chamber 010 with high-pressure water and drain the water from the source moving chamber 011. Next, when the solenoid valve 07 is set to the discharge side, the pump chamber 010 is connected to the fuel valve 15 and the source moving chamber 01
1 is connected to the high-pressure water pipe, and the pressure of the high-pressure water acts, and the discharge spool 01 is pushed leftward until it hits the stopper 4 to push the water in the pump chamber 010 into the fuel valve 15. The discharge spool system has the following problems. (1) Since it is water lubricated, a combination of a chrome-sprayed or WC-sprayed spool and a chrome-deposited SUS or AlBc-sprayed cylinder is combined, but the number of reciprocating slides is the same as the number of fuel injections (6. 7 × 10 ⁷ times) There is concern about wear resistance. (2) On the other hand, in terms of jetting characteristics, the amount of water must always be controlled to ± 1.5% (variation 3%), and if the sliding surface is worn (by increasing the gap by several μm), water will leak from the gap and will be discharged. The amount of water changes. A change in the water amount of water injection leads to a change in the fuel, resulting in a change in the engine output. An object of the present invention is to solve the above-mentioned problems and to provide a hydraulic drive type water injector having a large amount of abrasion resistance, a constant amount of water for a long period of time, and stable discharge characteristics.

[0005]

In a water injection system of an internal combustion engine, a discharge spool for adjusting the amount of water discharged from a pump to a fuel valve and supplying it to a fuel valve has an airtight seal on a sliding surface in a cylinder. A reciprocatingly provided discharge spool that forms two chambers facing both end faces in the cylinder, and supplies high-pressure oil to a chamber on one end face side of the discharge spool to serve as a drive source for the discharge spool. , Introducing water into the chamber on the other side and providing a check valve for water supply and discharge to create a water discharge chamber,
Moreover, a spool stopper for adjusting the stroke of the discharge spool is provided. A mold packing represented by U packing or V packing is applied as the airtight seal.

[0006]

The spool stopper 4 is set by adjusting the left stop position of the discharge spool. When water is introduced into the water discharge chamber and then high-pressure oil is supplied to the chamber on the other side, the high-pressure oil pushes the discharge spool and pushes the stroke volume of water injection in the water discharge chamber into the fuel valve through the check valve. High-pressure oil lubricates the sliding surface.

[0007]

EXAMPLE An example will be described with reference to FIG. FIG. 1 is a cross-sectional view of a hydraulically driven water injector of the embodiment. In the figure, 3 is a cylinder, and 1 is a discharge spool, which is loosely fitted in the cylinder 3. Reference numeral 2 denotes an airtight seal, such as a U packing or a V packing provided on the outer surface of the discharge spool 1. Four
Is a spool stopper provided on the cylinder 3
It is movable and fixed in the axial direction. Reference numeral 11 denotes an oil chamber, which is one chamber partitioned by the discharge spool 1 in the cylinder 3. A water chamber 10 is a chamber on the opposite side of the oil chamber 11 which is partitioned by the discharge spool 1 in the cylinder 3. Reference numeral 13 is a low-pressure water pump, and 5 is a water supply check valve, which is provided in a pipe connecting the low-pressure water pump 13 and the water chamber 10 and is opened only to the water chamber 10 side. A discharge check valve 6 is provided in a pipe that connects the water chamber 10 and the fuel valve, and opens only to the fuel valve side. 12 is a high pressure oil pump with a discharge pressure of 150 k
It is gf / cm ² . A solenoid valve 7 is provided in a pipe that connects the high-pressure oil pump 12 and the oil chamber 11.

The operation of the above embodiment will be described. By adjusting and fixing the position of the spool stopper 4, the stroke volume of the discharge spool 1 can be arbitrarily determined. Low pressure water pump 1
3 is operated and the solenoid valve 7 is set to the discharge side, the oil chamber 11 is connected to the oil discharge pipe, and the water discharged from the low-pressure water pump 13 is supplied to the water supply check valve 5
Open to fill the water chamber 10 and fill it. High pressure oil pump 1
2 is operated and the solenoid valve 7 is set to the refueling side, the high pressure oil pump 12
The discharged oil of (1) flows into the oil chamber 11, pushes the discharge spool 1 to the left, and the discharge spool contacts the spool stopper 4 and stops. As described above, the water in the water chamber 10 pushed by the discharge spool 1 opens the discharge check valve 6 and is pushed into the fuel valve. A pushing spring may be inserted between the discharge spool 1 and the spool stopper 4 to assist the returning force of the discharge spool 1. In this case, the discharge pressure of the low pressure water pump 13 can be further reduced. In the usual case, the discharge pressure of the low-pressure water pump is determined in consideration of the opening of the check valve and the spool resistance passage resistance.

[0009]

Since the present invention is configured as described above, (1) the sliding surface can be lubricated with oil, and (2) the application of the soft seal prevents the direct contact between the spool and the cylinder to prevent the sliding surface from being worn. It is possible to secure a certain amount of water over a long period of time to stabilize the discharge characteristics, and to reciprocate repeatedly to ensure the freedom of packing selection by the number of slides and to maintain the characteristics by regular packing replacement. I chose Therefore, the present invention can provide a hydraulically driven water injector having a large amount of wear resistance, a constant amount of water for a long period of time, and stable discharge characteristics.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a hydraulically driven water injector according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a water injection system of a diesel engine.

FIG. 3 is a diagram of a spool valve system.

[Explanation of symbols]

1 ... Discharge spool, 2 ... Airtight seal, 3 ... Cylinder, 4
... Spool stopper, 5 ... Water check valve, 6 ... Discharge check valve, 7 ... Solenoid valve, 10 ... Water chamber, 11 ... Oil chamber, 12 ... High pressure oil pump, 13 ... Low pressure water pump.

Claims (1)

[Claims] 1. A water injection system for an internal combustion engine, comprising: a reciprocating discharge spool (1) having an airtight seal (2) on a sliding surface in the cylinder and partitioning the inside of the cylinder into two chambers (11, 10). , The chamber (11) to which high-pressure oil that serves as a drive source of the discharge spool is supplied, the chamber (10) into which low-pressure water is introduced and which discharges water by the piston action of the discharge spool, and the discharge A hydraulic drive type water injector having a spool stopper (4) for adjusting the stroke of the spool.