CN86206152U

CN86206152U - Pumpless fuel injection unit for diesel engine

Info

Publication number: CN86206152U
Application number: CN 86206152
Authority: CN
Inventors: 李宗奎
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-08-22
Filing date: 1986-08-22
Publication date: 1987-06-10

Abstract

Disclosed is a pumpless fuel-injection unit, relating to the fuel system of the diesel engine. The fuel is inputted in the fuel-injection unit under the ordinary pressure and can enter in the mixing-chamber of an injector at the suction stroke of the engine. The fuel and the mixing gas of the air can enter in a precombustion chamber arranged in the injection unit, and the fuel and the mixing gas of the air can enter in a cylinder after injected out the injection unit by compression ignition. As a consequence, a piston can be pushed to do work through the complete combustion. The utility model has the advantages of simple structure, convenient operation and low failure rate. The engine using the utility model has stable work, small shock, smooth and soft running. The fuel injector of the utility model can be designed into the one whose appearance is similar to the conventional fuel injector to be installed on the conventional diesel engine.

Description

Pumpless fuel injection unit for diesel engine

The utility model relates to the fuel system of diesel engine, relates to the injection apparatus of normal pressure fuel feeding particularly.

In the evolution of modern diesel engine, people have proposed many different theories to the mode and the combustion process of fuel oil and the formation of Air mixing gas, can be divided into two kinds of citation forms of space atomizing hybrid mode and fuel film vaporization hybrid mode basically.The diesel engine of high-pressure injection fuel oil mainly relies on high-pressure system that high pressure fuel is sprayed into the high atomisation state to form mixed gas, and it belongs to space atomizing hybrid mode.Therefore the high pressure fuel pump of traditional diesel engine using and the device of oil sprayer guarantee engine running work.But the technological requirement height of the manufacturing of high pressure fuel pump and oil sprayer and material, price is expensive, in use be out of order easily, for example in the using process of the very big agricultural equipment Diesel engine of owning amount, fuel system trouble rates such as high-pressure service pump are higher than the rate of fault of other system.

In the fuel system of diesel engine, improved method and test were proposed once.Germany doctor Miu Leier propose " M process " be before the piston arrives top dead center, compression stroke phase not, fuel oil once sprays into the formation oil film.U.S.'s Southwest Research Institute has been carried out a series of no pumps to the single-cylinder double stroke diesel engine and has been started test (referring to the 2nd～10 page of " external internal-combustion engine " the 1st phase in 1972).Above-mentioned no pump starts test, projection is installed and is made projection before piston rises to top dead center at piston head, formed a main combustion chamber and a precombustion chamber between piston, projection and the cylinder head three, oil fuel handling plant is set and has linked up mutually with main combustion chamber and precombustion chamber.At piston stroking upward to top dead center in a flash, under the air pressure effect in main combustion chamber of fuel oil and air, through the passage of above-mentioned feedway, enter precombustion chamber, take fire under the set glow plug effect of precombustion chamber, motor promptly starts running.The no pump burner oil system of this test, high pressure oil pump, injector nozzle matching parts have been omitted, relatively simple for structure, realized the trial run of motor, but it need change the shape or the structure of members such as cylinder, piston, need be by glow plug ability startup work, its deficiency is that the formation and the combustion process of mixed gas is abundant inadequately, and need set up glow plug and annex thereof.

A kind of reasonable in design, no pump oil-fired system that can realize the diesel engine proper functioning is that people urgently wish the test that solves or the problem of application.

The purpose of this utility model is to propose a kind of fuel of realizing diesel engine normal pressure fuel feeding with air formation mixed gas and burn, and is provided with the no pump fuel injection apparatus of mixing chamber, precombustion chamber.

Mixture formation process of the present utility model, basically the type that belongs to fuel film vaporization, just oil-feed and form oil film when the aspirating stroke of motor, be heated evaporation, negative pressure when it has made full use of the cylinder aspirating stroke, air swirl during compression stroke and the high temperature of motor, form fuel oil and Air mixing gas and finally voluntarily fire burns, generation volumetric expansion and work done.The formation and the combustion step of mixed gas are: fuel oil enters injection apparatus inside when the engine charge stroke; When being compressed, injection apparatus intermediate fuel oil and air form mixed gas and finally by compression ignite; By compression ignite and the mixed gas of volumetric expansion sprays into cylinder, firing chamber by injection apparatus inside, perfect combustion and promote the piston work done.

Realize the injection apparatus of said method, comprise oil fuel handling plant, oil transport pipeline and spout.The inside of injection apparatus is provided with the space of precombustion chamber, the space of the mixing chamber that links by connection mouth with precombustion chamber, and mixing chamber links with fuel oil oil transportation road and is provided with and outer spout that cylinder, firing chamber are linked up mutually.

The utility model can be obtained following good effect:

(1) reformed diesel fuel system, annex such as exempted that traditional high pressure fuel pump and transmission device thereof, high pressure fuel injector are chewed reduces the manufacture cost of diesel engine;

(2) fuel injection apparatus is simple in structure, does not need glow plug heating can make mixture combustion, and in use good reliability, rate of fault are low;

Vibration when (3) diesel engine of the present utility model being set than conventional diesel engine work running is little, work is smooth-goingly gentlely closed, noise is low, for example installs and uses the fatigue that will reduce hull structure on marine diesel engine, extends using period, improves a travelling comfort of taking advantage of;

When (4) fuel injector was in use with Maintenance and Repair, it was easy to have an installing/dismounting, and the maintenance verification is advantage easily, and it does not need to be equipped with high-pressure service pump checking apparatus or oil injecting nozzle calibrator;

(5) profile of the utility model sparger can be designed to profile similar to high pressure fuel injector or installation dimension on demand, therefore can replace conventional fuel system, is installed on the existing conventional diesel engine.

Below in conjunction with embodiment and accompanying drawing, the utility model is described in detail.

Fig. 1 is a workers and peasants 195-C2 type single-cylinder four-stroke diesel engine, and the schematic representation of conventional high pressure fuel injector is installed;

Fig. 2 is the schematic representation that a kind of sparger of the present utility model is installed in running work on Fig. 1 motor;

Fig. 3 is the structural representation that can be used for a kind of fuel injector example of Fig. 1 diesel engine;

Fig. 4 is a kind of variation of Fig. 3 fuel injector;

Fig. 5 is the exploded view of Fig. 3 fuel injector part.

With reference to Fig. 1, the utility model with workers and peasants 195-C2 type single-cylinder four stroke diesel engine 30 as a kind of test engine.This motor has been installed conventional high pressure fuel injector 31, as shown in the figure.

With reference to Fig. 2, the fuel injector 20 of a kind of example of the utility model is installed on the single-cylinder four-stroke diesel engine 30 shown in Figure 1, the outer nozzle holes 11 of sparger 20 is linked up with cylinder 33, firing chamber 32, and its mounting point is identical with the mounting point of former engine high pressure oil sprayer.The needle-valve 1 of oil fuel handling plant is connected with flow control mechanism, connects oil inlet pipe 2 and cooling water intake 8 and outlet 9, can ato unit 30.

With reference to Fig. 2 and Fig. 3, the formation of the air of no pump diesel engine and burning working procedure are: fuel oil enters the space of sparger mixing chamber 5 when suction stroke; When being compressed, air and fuel oil form mixed gas through mixing chamber 5, and in the space of sparger precombustion chamber 7 by compression ignite; The mixed gas volume expansion that takes fire sprays into engine chamber 32 and cylinder 33 by the inside of sparger 20, thus perfect combustion and the work done of promotion piston.

Upper half part of Fig. 3 is the fuel delivery part, and lower half portion is the main body of sparger 2.The fuel oil input flow rate of needle-valve 1 control oil inlet pipe 2, fuel oil is equipped with safety check 3, oil transportation road 4 and the mixing chamber fuel inlet 16 of spring 14, to the mixing chamber 5 of sparger bottom through fuel oil chamber 15.Main jet pipe 6 is set in the space of mixing chamber 5, and the top of mixing chamber 5 is provided with precombustion chamber 7, and connecting port 12 is communicated with each other the space of mixing chamber 5 and the space of precombustion chamber 7.The lower end of mixing chamber 5 is provided with the outer nozzle holes 11 that links with engine chamber 32, cylinder 33.

Fig. 3 lower half portion, the inside of sparger 20 are established and are caused cover 13.The inner space of causing cover 13 is a precombustion chamber 7, matches with precombustion chamber shell 25 and contact in the outside of initiation cover 13.Cooling jacket 10 is arranged in the precombustion chamber shell 25, and it is equipped with the pipeline of cooling water intake 8 and outlet 9.Cooling water makes precombustion chamber shell 25 keep suitable operating temperature, and the part periphery 29 that causes cover 13 matches with precombustion chamber shell 25 and contacts, thereby feasible precombustion chamber 7 spaces of causing cover 13 and its inside, remains on the scope of appropriate operating temperature.

For four stroke engine, fuel injector 20 is as follows in the working condition of each stroke.(1) aspirating stroke; Because of the quick descending negative pressure that in cylinder, produces of piston, a large amount of air enter cylinder through intake valve, the fuel oil of some is by oil inlet pipe 2, needle-valve 1, fuel oil chamber 15, safety check 3, oil transportation road 4 and the fuel inlet 16 of feedway in addition, enter mixing chamber 5, adhere to the periphery that is distributed in main jet pipe 6 and the space of mixing chamber 5, and, make the part fuel oil that enters mixing chamber be heated, evaporate because of the high temperature that the last working stroke of motor is produced; (2) compression stroke: piston stroking upward, with the air compression in the cylinder, compressed-air actuated air communication is crossed outer nozzle holes 11, main jet pipe 6 and mixing chamber 5, make the fuel oil in the mixing chamber 5 be forced to atomizing, and further be compressed by connecting port 12 and enter the precombustion chamber 7 that links with mixing chamber 5, certain that will arrive budc at the compression stroke piston in a flash, fuel oil and Air mixing gas in precombustion chamber 7 beginnings by compression ignite; (3) working stroke: when being arrived greater than cylinder pressure by the expansion of the mixed gas volume of compression ignite, increased pressure, the mixed gas of precombustion chamber 7 internal combustion begins back spray, clear away the periphery of main jet pipe 6 and fuel oil or the evaporative gas in mixing chamber 5 spaces once more through connecting port 12, mixing chamber 5 and main jet pipe 6, make their further mixing, pass through outer nozzle holes 11 at last, spray to firing chamber 32 cylinders 33, thus with cylinder in air perfect combustion.(4) exhaust stroke: waste gas after burning is pushed out cylinder, and sparger is prepared to begin task again from suction stroke next time.

As mentioned above, oil-fired system of the present utility model is to carry fuel oil under the situation of common pressure, and it need not be provided with high pressure fuel pump.In order to ensure the reliability of feedway, generally can adopt the discharge pressure of 0.3～0.8kg/cm at oil inlet pipe 2.Precombustion chamber 7, UNICOM's interface 12, mixing chamber 5, main jet pipe 6 and outer spray orifice oral pore 11 Position Design generally speaking are the center line setting generally along sparger 20.

For the multiple cylinder diesel motor, oil-fired system of the present utility model can be carried fuel oil to a plurality of fuel injectors 20 by the oil transportation road 4 of fuel oil, makes engine running work.

With reference to Fig. 4, for different designing requirements, perhaps different engine operation requirements, the design parameter of fuel injection apparatus, the for example bore of the bore of the shape of the latus rectum of the spatial form of the spatial form of mixing chamber 5 and volume, precombustion chamber 7 and volume, main jet pipe 6 and jet pipe and length, connecting port 12 and shape, outer nozzle holes 11 and shape or the like, can be as calculated or test obtain appropriate numerical value.The cylindrical precombustion chamber 7 of sparger shown in Figure 3 can adopt spherical precombustion chamber 7, as shown in Figure 4.

With reference to Fig. 5, the part of fuel injector can be made knockdown assembly structure according to the designing requirement of its working principle.Sparger 20 shown in Figure 3 is exactly a kind of assembly structure, and its component part puts in order the position by the part installation by the axis of sparger.Begin spout cap 21 from the ejection end of sparger 20 for nozzle holes outside having 11, have the main jet pipe 6 that installs and fixes ring 22 and spout 28, mixing chamber shell 23, be provided with the mixing chamber of UNICOM's mouth 12 and the connecting sheet 24 of precombustion chamber, inner initiation cover 13 for precombustion chamber 7 outer installment annular protrusions 29, the precombustion chamber shell 25 that causes cover 13 is installed, above-mentioned part is assembled into the main body of sparger 20, promptly constitutes the outer spray orifice mouth 11-mixing chamber 5 shown in Figure 3 and the luminal space structure of the main jet pipe 6-mouth 12-of UNICOM precombustion chamber 7.

The upper end of sparger 20 is the fitting seat 27 that needle-valve 1 and oil inlet pipe 2 are housed, and it is connected with precombustion chamber shell 25 by connecting packing ring 26, thereby constitutes the fuel injection apparatus that comprises fuel delivery, flow control device and injector body.

The profile of sparger 20, comprise spout cap 21, mixing chamber shell 23, precombustion chamber shell 25 and fitting seat 27, can be designed as profile similar and size to conventional high pressure fuel injector, establish the through hole 35 that is used for fixing on the fitting seat 27, pass through fastening piece, sparger is fixed on the oil sprayer position of motor, as shown in Figure 2.

Present embodiment is through overtesting, situation such as following table:

The former motor of project uses no pump fuel oil

The injector testing of workers and peasants 195-C2 type

Compression ratio 19.5 19.5

The fuel system high pressure fuel pump does not have the fuel injection of pump

The high pressure fuel injector apparatus

Starting performance is easier to

1900 rev/mins 300～2200 rev/mins of full rotating speeds

Moving commentaries on classics situation normal temperature, idling is low and steady

Oil consumption 200 gram/horsepower-hour close

Exhaust is except that at a high speed, and is smokeless substantially

10 horsepowers of output powers 1976 70%

1978 93%

1980 100～113.9%

Claims

1, a kind of fuel injector of diesel engine normal pressure fuel feeding, comprise oil fuel handling plant, oil transport pipeline and spout,, the space of the mixing chamber 5 that it is characterized in that being provided with in the shell 25 of described sparger 20 space of precombustion chamber 7, links by connection mouth 12 with precombustion chamber 7, described mixing chamber 5 link with oil transportation road 4 and are provided with and outer spout 11 that engine chamber, cylinder are linked up mutually.

2, sparger as claimed in claim 1 is characterized in that precombustion chamber 7 is provided with heat conduction spacer 13.

3, sparger as claimed in claim 1 is characterized in that being provided with main jet pipe 6 in the space that mixing chamber 5 limited.

4,, it is characterized in that the position of precombustion chamber 7, mixing chamber 5, UNICOM's interface 12, main jet pipe 6 and outer nozzle holes 11, generally along the center line setting of sparger 20 as claim 1 or 3 described spargers.

5, sparger as claimed in claim 2 is characterized in that being shaped as of sparger precombustion chamber 7 is cylindrical.

6, sparger as claimed in claim 2 is characterized in that the sphere that is shaped as of sparger precombustion chamber 7.

7, sparger as claimed in claim 1 or 2 is characterized in that described shell 25 is provided with cooling jacket 10 at the position that holds precombustion chamber heat conduction spacer 13.