JPH02140459A - Fuel injector for engine - Google Patents

Abstract

PURPOSE:To control the injection feeding of fuel mixed with vapor by connecting in offset an injector holder portion to a fuel feeding passage portion, and providing an injecting opening and fuel intake openings at specific positions. CONSTITUTION:An injector holder portion 17 is connected in offset in the radius direction of a fuel supply pipe 12. The injecting opening 16a of an injector 16 is located at the lower part than the annular fuel supply pipe 12. Fuel-taking in openings 31 that open at the lower half portion of the annular fuel supply pipe 12, are provided at the injector 16. Thus, to make the perimeter of an air intake passage 5 compact is realized. In addition, fuel mixed with vapor being injected and supplied to the inside of a cylinder can be firmly restrained.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a fuel injection device for an engine.

(Prior Art) Generally, in a fuel injection device for an engine, a fuel distribution pipe is branched from a fuel supply pipe located at the back of the injector, an injector is connected to this fuel distribution pipe, and the injector is connected so that its injection port is in the intake passage. The injector is fitted and supported so as to face the injector, and the fuel led from the fuel supply pipe to the fuel distribution pipe is taken in from the fuel intake port of the injector and injected into the intake passage from the injection port.

However, in the case where a fuel distribution pipe is provided in the fuel supply pipe as described above, fuel remains in the fuel distribution pipe and injector while the engine is stopped, so some of this accumulated fuel is absorbed when the engine is stopped. The fuel then evaporates due to heat and other factors, creating bubbles in the fuel, resulting in paper-laced fuel, which is then injected from the injector when the engine is restarted. In that case, the amount of fuel injected from the injector is controlled so that its volume value (pressure x opening time x opening area) is the target value, so if "fuel mixed with vapor" is supplied, the injector There was a problem in that the amount of fuel injected would be inconsistent, making it impossible to obtain an appropriate amount of fuel injected.

Therefore, in order to solve the above-mentioned problems, conventionally, for example, in the method disclosed in Japanese Utility Model Application Publication No. 165470/1982, a fuel supply pipe is attached to the intake manifold, and a fuel intake port is connected to the fuel supply pipe. The bottom flow type injector is installed directly on the side near the injection port.

According to this, the above-mentioned fuel distribution pipe can be eliminated, and the amount of the above-mentioned stagnant fuel is reduced accordingly, thereby reducing the amount of "pepper-containing fuel", which is preferable.

(Problem to be solved by the invention) However, even in this device, bubbles are generated near the injection ports of each injector due to heat from the engine cylinder during engine operation, and these bubbles are generated downstream of the fuel supply pipe. As paper accumulates in a snowballing manner toward the side, a considerable amount of paper-containing fuel is delivered into the injector holder (fuel intake port of the injector) located downstream of the fuel supply pipe. There is a problem.

In this case, a bypass pipe is provided that bypasses the injector holder separately from the above fuel supply pipe, and a constriction part is provided in the fuel supply pipe upstream of each injector holder to prevent the flow of "fuel mixed with vapor." By “
A system has been proposed in which fuel mixed with paper escapes into a bypass pipe so that it is not sent to the fuel supply pipe (see Japanese Patent Laid-Open No. 61-4861). However, in this system, a separate bypass pipe is Therefore, there is a problem in that the fuel supply layout cannot be made more compact.

The present invention uses paper-mixed fuel that is lighter in specific weight than paper-free fuel in the fuel supply pipe.
The purpose of this system is to use a single fuel supply pipe, in which only ``fuel without vapor contamination'' is delivered to the fuel intake port of the injector. It is about guiding.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention provides a fuel supply passage section and an injector holder section that is attached to an intake passage constituent member of an engine and connected to the fuel supply passage section. and an injector fitted into and supported by the injector holder, the fuel in the fuel supply passage being taken in from the fuel intake port of the injector and injected into the intake passage from the injection port. This assumes a fuel injection system for an engine with a The injector holder section is offset and connected to the fuel supply passage section, the injection port is positioned below the fuel supply pipe, and the fuel intake port is positioned a predetermined distance below the top of the fuel supply pipe. The structure is such that the opening is made at a certain position.

(Function) With the above configuration, in the present invention, in the fuel supply pipe, the fuel with light specific weight "fuel mixed with vapor" is distributed in the upper layer, and the "fuel not mixed with paper" with heavy specific weight is distributed in the lower layer. I will do it.

In that case, the "vapor-containing fuel" in the upper layer passes through a position a predetermined distance higher than the top of the offset portion (injector holder portion) of the fuel supply pipe that passes along the outer circumferential side of the injector.

On the other hand, since the injection port of the injector is located below the fuel supply pipe, and the fuel intake port of the injector opens at a predetermined distance lower than the top of the fuel supply pipe, vapor from the lower layer may be mixed in. The remaining fuel is taken into the injector from the fuel intake port and guided to the injection port.

For this reason, for example, in a case where each injector is arranged in series with the fuel supply pipe, even if "fuel mixed with vapor" increases as you go downstream of the fuel supply pipe, "fuel mixed with paper" will increase. No fuel is supplied to the injector.

Furthermore, since no piping is provided other than the fuel supply pipe, the area around the intake passage can be made more compact.

(Example) Embodiments of the present invention will be described below based on the drawings.

3 to 5 show a V-type six-cylinder engine to which a fuel injection device according to an embodiment of the present invention is applied. In these figures, 1 is a cylinder block, 2.3 is a cylinder head disposed on the cylinder block 1, and the cylinder block 1 and cylinder heads 2 and 3 form a left bank L and a right bank R. 3 cylinders 4. ...
are formed respectively.

On the bank open side of the cylinder head 2.3, there is an intake passage 5.3 that supplies intake air to the cylinders 4 of each bank L, R. ... are provided for each. Above intake passage 5. . . . is a cylinder 4. whose one end is in each bank L and R.・
..., and the other ends are gathered from the front in odd numbers and even numbers, respectively, and face forward and rearward in the cylinder row direction, and are reversed at the front and rear ends of the right bank R to face rearward and forward in the cylinder row direction. , are connected to the surge tank 6 above the right bank R, respectively. The surge tank 6 is exposed to the atmosphere via an air cleaner (not shown). In addition, 7.8 is a cylinder head cover arranged on the cylinder heads 2 and 3, respectively.

Also, bank L of the cylinder heads 2 and 3.

Between R, the above-mentioned intake passage 5. . . . communicates with one end of the cylinders 4 in each bank L, R. A cover member 11 is provided as an intake passage constituent member that connects the intake passages 5° with each other. Moreover, the cover member 11 on which the upper front and rear surfaces and the left and right side surfaces of the cover member 11 are located
An annular fuel supply pipe 12 (fuel supply pipe) is attached to the outer peripheral surface side of the fuel supply pipe. On the left bank side of the annular fuel supply pipe 12, the other end of a first fuel supply pipe 14 is connected at one end to a pulsation damper 13 for reducing noise caused by pulsation of fuel by a fuel pump (not shown). are connected. The pulsation damper 13 is connected to the other end of a second fuel common supply pipe 15 whose one end is connected to a fuel tank (not shown), and the fuel pump pumps the fuel in the fuel tank. is introduced to the pulsation damper 13 via the second fuel supply pipe 15 and then flows through the annular fuel supply pipe 12 via the first fuel common supply pipe 14. Also, the cylinders 4. in each bank L, R of the cylinder head 2.3 are An injector holder 17 . ... (injector holder parts) are connected in series, and the injector holder 1
7, each bank L, R of the cylinder head 2゜3.
Intake passage inside 5. Six injectors 16. ... are respectively inserted and supported.

Each of the above-mentioned injectors 16 is of a bottom flow type, in which a fuel intake port 31 (described later) is provided on the side near the injection port 16a, is directly attached to the annular fuel supply pipe 12, and the inside of the annular fuel supply pipe 12 is injected. The circulating fuel is guided to the injection port 16a of the injector 16.

Furthermore, 21 is a pressure regulator that adjusts the fuel pressure in the annular fuel supply pipe 12 of each of the injectors 16, and the pressure regulator 21 has a pressure regulator on the left bank side (first fuel supply side) of the annular fuel supply pipe 12. The other end of the pressure regulating passage 22, one end of which communicates with the other end of the pipe 14 (closer to the front than the other end of the pipe 14), and the other end of the fuel return passage 23, one end of which communicates with a fuel tank (not shown), are connected to each other. , a negative pressure passage 2 whose one end communicates with the surge tank 6
The other ends of 4 are connected. Furthermore, a stopper 25 that prevents the flow of fuel is provided in the annular fuel supply pipe 12 located between the first fuel common supply pipe 14 and the other end of the pressure adjustment passage 22. The fuel in the annular fuel supply pipe 12 flows through the annular fuel supply pipe 12 on the side opposite to the stopper 25 and is returned from the pressure adjustment passage 22. When the pressure value of the fuel from the pressure adjustment passage 22 is higher than the intake negative pressure value from the negative pressure passage 24, the pressure regulator 21 returns the fuel to the fuel tank via the fuel return passage 23 to lower the fuel pressure value. On the other hand, when the fuel pressure value from the pressure adjustment passage 22 is lower than the intake negative pressure value from the negative pressure passage 24, communication between the pressure adjustment passage 22 and the fuel return passage 23 is cut off to increase the fuel pressure value. There is.

As a feature of the present invention, as shown in FIG. 1 and FIG. The injector holder 17 is fitted into the injector holder 17 with the center line l inclined by α (12'). The center line l of the injector 16 and the center line 1' of the injector holder 17 coincide, and the center line 1) of the injector 16 coincides with the center line n of the annular fuel supply pipe 12. The injector holder 17 is offset in the radial direction (outward side) of the annular fuel supply pipe 12 so that the injector holders 17 are not orthogonal to each other.
The cross-sectional shape of 7 and the cross-sectional shape of the annular fuel supply pipe 12 are integrally connected in an overlapping state, and the annular fuel supply pipe 12 communicates with the injector 16 by bypassing the outer peripheral surface side thereof. ing. Further, the injection port 16a of the injector 16 is located below the annular fuel supply pipe 12. The injector 16 is provided with a fuel intake port 31 that opens in the lower half of the annular fuel supply pipe 12.

In FIG. 1, reference numeral 33 denotes an injector fixing holder that holds the injector 16 in the injector holder 17 via a presser rubber 35 while closing the opening 34 that opens above the ζ injector holder 17. The injector fixing holder 33 is fastened to the injector holder 17 with bolts 36, 36.

Further, in FIG. 2, 37 is an electrode that applies an electric pulse to a solenoid (not shown) provided in the injector 16.

Next, the operation and effect of the above embodiment will be explained. In the annular fuel supply pipe 12, the fuel with light specific weight "fuel mixed with paper" is in the upper layer, and the fuel with heavy specific weight "fuel not mixed with vapor" is in the upper layer. '' will be distributed in the lower layer.

In that case, the "vapor-containing fuel" in the upper layer will pass through a position a predetermined distance higher than the top of the offset portion (injector holder 17 side) of the annular fuel supply pipe 12 that passes along the outer circumferential side of the injector 16. .

On the other hand, the injection port 16a of the injector 16 is located below the annular fuel supply pipe 12, and the fuel intake port 31 of the injector 16 opens at a predetermined distance lower than the top of the annular fuel supply pipe 12. Therefore, the "vapor-free fuel" in the lower layer is taken into the injector 16 from the fuel intake port 31 of the injector 16 and guided to the injection port 16a. For this reason, by arranging the injector 16 in series with the annular fuel supply pipe 12, as you go downstream of the annular fuel supply pipe 12, "
Even if “vapor-contaminated fuel” snowballs,
"Fuel mixed with vapor" is not supplied to the injector 16.

Moreover, since no piping is provided other than the annular fuel supply pipe 12, the intake passage 5. ...The surrounding area is made more compact.

As a result, the intake passage 5. ...It is possible to reliably suppress "fuel mixed with vapor" from being injected into the cylinder 4 from the injection port 16a of the injector 16 through the annular fuel supply pipe 12 while making the surroundings more compact.

Incidentally, in the above embodiment, the application was described to an engine having a plurality of cylinders (cylinder 4), but it goes without saying that the invention may be applied to an engine having a plurality of cylinders arranged in series or a single cylinder engine. It is.

(Effect of the invention)

Claims (1)

[Claims] (1) A fuel supply pipe that is attached to an intake passage constituting member of an engine and has a fuel supply passage section and an injector holder section connected to the fuel supply passage section, and an injector that is fitted and supported in the injector holder section. In the fuel injection device for an engine, the fuel in the fuel supply passage is taken in from the fuel intake port of the injector and injected and supplied from the injection port to the intake passage, wherein the injector holder is connected to the fuel supply passage. An engine characterized in that the injection ports are connected in an offset manner, the injection port is located below the fuel supply pipe, and the fuel intake port opens at a predetermined distance lower than the top of the fuel supply pipe. Fuel injection device.