JPH04241770A - Fuel supply device for internal combustion engine - Google Patents

Abstract

PURPOSE:To ensure an atomized condition of fuel at both cold and warm times of an internal combustion engine so as to always obtain a good combustion condition by selectively directing an injection direction of fuel to both a fuel heating means and except this means while providing a fuel injection means and the fuel heating means. CONSTITUTION:An intake manifold 5 is mounted to a cylinder head 2 through a gasket 4B to fix an injector 7 to a branch pipe 5a of the intake manifold. A heater 8 is fixed to the branch pipe 5a in an intake port lower side part 2a of the cylinder head 2. When an engine is cold, mixed gas, jetted from the injector 7, collides against the heater 8 to perform atomization and efficient combustion in a combustion chamber 18. On the other hand, when the engine is warmed, the mixed gas is directed not to the heater 8 but to the center of an intake valve seat 11. Then, the mixed gas, without coming into contact with the heater 8 cooled with no electrification, is atomized by heat of the engine to efficiently perform combustion in the combustion chamber.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply system for an internal combustion engine.

0002

2. Description of the Related Art In a spark ignition internal combustion engine, such as a gasoline engine, a carburetor is used to mix gasoline with intake air and supply the mixture to a combustion chamber. The carburetor has the function of atomizing gasoline using negative pressure inside the engine and automatically supplying an appropriate amount of air as needed to create a flammable gas (mixed gas).

To explain this with reference to FIG. 12, the throttle body 71 is formed as a venturi tube with a narrowed diameter in the intermediate region, and air 72 is supplied from the air supply port through a choke valve 73 to the float chamber. (
(not shown) is atomized at the tip of the nozzle 75. This mixed gas MG of atomized gasoline and air is preheated via a butterfly valve 74 from a carburetor 76 and passes through a honeycomb heater 77, and then passes through a branch pipe of the intake manifold 5 to the combustion chamber of the engine (both not shown). be guided. Note that the throttle body 71 and the intake manifold 5 are made of an insulating material (
They are airtightly integrated with an insulator 78 sandwiched therebetween and a gasket 79 interposed therebetween. The honeycomb heater 77 has a large number of densely formed gas passages 77a, and by energizing the heater itself, it heats the passing mixed gas to a predetermined temperature, thereby preventing knocking and saving fuel consumption. is being done. A hot water passage 5f is formed in the manifold 5, through which heated cooling water passes through a water cooling jacket surrounding a cylinder liner (not shown). Generally, the honeycomb heater 77 is activated when the engine coolant temperature rises (for example, 70°C) to save battery power.
), the device is configured to stop energizing.

[0004] Particularly in passenger cars, fuel injectors have recently become popular in place of carburetors for the purpose of purifying exhaust gas. The fuel injector actively atomizes and injects gasoline without relying on negative pressure inside the engine, and can be installed near the combustion chamber, so it can be used at low temperatures (especially when starting the engine in winter or in cold regions). ), it liquefies the fuel, reduces wall flow, approaches ideal combustion, purifies exhaust, and improves engine response (startability and acceleration). In particular, an electronically controlled fuel injection system in which the amount of intake air is detected by a sensor and the amount of gasoline injected is controlled by a computer has the advantage of always supplying a mixed gas under optimal conditions.

FIG. 13 is a sectional view showing the main parts of an engine provided with a fuel injector. A fuel injector (hereinafter simply referred to as an injector) 7 is provided for each branch pipe 5a of the intake manifold 5, and fuel is injected into the cylinder head 2 across the straight line connecting the injector 7 and the center of the intake valve seat 11. A heating device (hereinafter referred to as a heater) 80 is provided.

A mixed gas of atomized gasoline and air (hereinafter simply referred to as mixed gas) injected from the injector 7.
The MG contacts the heater 80, enters the combustion chamber 18 through the open valve seat 11 when the intake valve 9 is opened, and is ignited by the spark plug 17 after the intake valve 9 is closed.
It burns and the engine runs.

[0007] When the engine is started in winter or early in the morning, the engine is cold, and the mixed gas MG is efficiently combusted by being heated by contacting the heater 80 whose temperature has been raised by supplying electricity.

[0008] In summer or after a considerable amount of engine operation time has elapsed,
Since the engine is warmed up, there is no need to heat the mixed gas MG, and the power supply to the heater 80 is stopped. For this reason, when the engine is warm, the mixed gas MG comes into contact with the heater 80, which is not energized and is cold, resulting in ■ a decrease in engine output due to an increase in intake fluid resistance, and ■ a delay in combustion due to gasoline scattering, resulting in a deterioration in response. (2) The scattered gasoline adheres to the inner surface of the cylinder head 2 and the intake manifold branch pipe 5a, condenses and becomes droplets, and even worse, wall flow occurs, increasing the production rate of HC and CO, and contaminating the exhaust gas. Further, there arises a problem that fuel efficiency also deteriorates.

[0009] As described above, installing a heater is convenient when the engine is cooled, but becomes more inconvenient when the engine is warmed up. On the other hand, if the heater is not installed, the above-mentioned problem does not occur when the engine is warm, but when the engine is cold, the inconvenience of low fuel combustion efficiency occurs. In other words, the heater has antinomic characteristics.

For this reason, as shown in FIG. 13, the injector 7
Either the fins 80a of the finned heater 80 are arranged on a straight line connecting the center of the intake valve seat 11 and the center of the intake valve seat 11, thereby causing the above-mentioned problem when the engine warms up, or the heater is positioned slightly away from the straight line. Compromise designs have also been attempted, such as arranging the engine to accommodate both cold and warm engine conditions. However, the latter design is not satisfactory because it does not provide ideal fuel supply to the combustion chamber both when the engine is cold and when it is warm.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel supply device for an internal combustion engine that can maintain an atomized state of fuel both when the engine is cold and when it is warm, and can always supply fuel under appropriate combustion conditions. It is said that

0012

SUMMARY OF THE INVENTION The present invention comprises a fuel injection means and a fuel heating means for heating the fuel injected from the fuel injection means, and the injection direction of the fuel is directed toward the fuel heating means. The present invention relates to a variable-direction fuel supply device for an internal combustion engine that is configured to be oriented toward either of the following directions (for example, toward the inlet of a combustion chamber 18, which will be described later). Note that the above-mentioned "injection direction" refers to the direction of the central axis of the region where fuel is injected.

[0013]

[Examples] Examples of the present invention will be described below.

FIG. 1 is a sectional view of the vicinity of a combustion chamber of an overhead camshaft (OHC) type gasoline engine.

Gasket 4A is placed on the cylinder block 1.
Cylinder head 2 is fixed via. Note that the cylinder head 2 is made of aluminum alloy. The intake valve 9 is fitted into the valve guide 13 press-fitted into the cylinder head 2 so as to be able to reciprocate, and comes into contact with the intake valve seat 11 . In the figure, 9a is a valve head, 9b is a valve face, and 9c is a valve stem. The intake valve 9 is biased by a spring 14 and comes into contact with a camshaft 16 via a tappet 15. The exhaust valve is also attached to the cylinder head 2 using the same mechanism as the intake valve 9, but
This is hidden in the intake valve and is not visible in the diagram. The piston 19 is inserted into a cylinder liner 3 press-fitted into the cylinder block 1, sealed by a first pressure ring 20A and a second pressure ring 20B, and the supply of lubricating oil is controlled by an oil scraper ring 20C. A water cooling jacket 23 is formed on the outside of the cylinder liner 3, and the water cooling prevents the cylinder liner 3 from overheating. The lower portion 2a is heated. An intake manifold 5 is attached to the cylinder head 2 via a gasket 4B, and an injector 7 is fixed to a branch pipe 5a of the intake manifold 5. A heater 8 is embedded and fixed with its surface exposed near the intake manifold branch pipe 5a in the lower intake port portion 2a of the cylinder head 2.

FIG. 1 shows the state of the piston 19 just before it reaches the top dead center, and 22 is a connecting rod that is swingably attached to the piston 19 by a piston pin 21. As shown in FIG. In this position of the piston 19, the intake valve 9 is moved by the spring 1 due to the rotation of the camshaft 16.
4 to the position shown by the solid line, the space between the intake valve 9 and the intake valve seat 11 is opened, and the mixed gas enters the combustion chamber 18. The mixed gas that has entered the combustion chamber 18 is ignited by the spark emitted from the spark plug 17 and explodes, pushing down the piston 19 and pushing down the connecting rod 22.
Rotate the crankshaft (not shown) located below clockwise in the figure. At this time, the intake valve 9 is in its original position shown by the imaginary line, and the valve face 9b is in contact with the face 11a of the intake valve seat, sealing the combustion chamber 18 together with the intake valve seat 11.

When the engine is cold, the mixed gas MG1 ejected from the injector 7 shown by the phantom line collides with the heater 8, is heated, becomes atomized, and is further directed to the combustion chamber 18 together with the intake air (or mixed gas) A. is rectified and burns efficiently.

When the engine is warmed up, the center of the injection direction of the mixed gas is directed not toward the heater 8 but toward the center of the intake valve seat 11. Then, the mixed gas MG2 ejected from the injector 7 shown by the solid line is atomized by the heat of the engine,
It is directly introduced into the combustion chamber 18 through the opening in the valve seat 11 without contacting the heater 8 . Therefore, the above-mentioned problems caused by the heater do not occur, and efficient combustion is achieved in the same way as when the engine is cold.

When the engine is warmed up, the following effects can be obtained. The mixed gas MG2 collides with the curved surface of the valve head 2a located immediately near the intake valve seat 11 of the intake valve 9, is supplied with heat from the valve head 9a, becomes atomized, and spreads in a fan shape into the combustion chamber 18. and ideal combustion takes place. At the same time, the intake valve 9
Since heat is removed by the mixed gas MG2 for cooling, good dimensional accuracy is maintained even when the engine is warm.

As described above, the center line of the injection area of the mixed gas is displaced by the angle α between CL1 and CL2, and the mixed gas is in an ideal state both when the engine is cold and when it is warm. is supplied to the combustion chamber, ensuring efficient combustion at all times.

FIG. 2 is a schematic front view (partially in section) showing how to change the mixed gas injection direction. The injector 7 is swingably supported at its tip via a flexible packing 38 in an injector support cylinder 5c provided in the intake manifold branch pipe 5a. The rear end of the injector 7 is connected to a solenoid 42 attached to the branch pipe 5a via a stand 44.
The solenoid 42 is connected to a coil spring 43.
It is urged toward the stand 44 side by.

When the solenoid 42 is energized, the solenoid 42 rises against the biasing force of the coil spring 43, and the injector center axis CL is located as shown by the dashed line. When the energization to the solenoid is stopped, the solenoid 42 is lowered by the biasing force of the coil spring 43, and the injector center axis CL is located at the position shown by the two-dot chain line. The angle formed by both central axes is α.

The structure of the injector 7 is as shown in FIG. The injector body 27 is supported within the adapter 29 by a body support 28 . A needle 31 is inserted into the main body 27, and a core 32 is attached to the rear end side. The needle 31 is urged forward by a return spring 34 to close the nozzle 30 at the tip of the main body. When the electromagnetic coil 33 disposed at the rear of the core is energized, the core 32 is attracted by the electromagnetic coil 33 and moves rearward, the nozzle 30 opens, and gasoline from the fuel introduction pipe 36 is ejected from the nozzle 30. In the figure, 37 is a terminal for operating the electronic coil.

FIG. 4 is an enlarged cross-sectional view of the tip of the injector (
FIG. 5 is an enlarged sectional view taken along the line V-V in FIG. 4). The injector 7 is supported within an injector support cylinder 5c provided in the intake manifold branch pipe 5a via a flexible packing 38 and an O-ring 39A. An air introduction pipe 41 is attached within the injector support cylinder 5c, and a through hole 5d communicating with the air introduction pipe 41 is provided. The adapter 29 is provided with through holes 29a at six locations,
At the tip of the adapter 29, a truncated conical opening 29c is formed by an inclined surface 29b. Air supplied from the air introduction pipe 41 enters the space 40 between the injector support cylinder 5c and the adapter 29 as shown by the arrow in FIG. The mixed gas MG is mixed with gasoline ejected from the nozzle 30 to form a mist-like mixed gas MG.

FIG. 6 is a schematic diagram showing the outline of gasoline supply to the injector. Multiple cylinders (4 cylinders in this example)
The injectors 7 provided corresponding to each cylinder of the engine are connected to a common fuel supply main pipe 45 through a fuel introduction pipe 36 on the rear end side. The gasoline in the fuel tank 48 is driven by the fuel pump 49 and returns to the fuel tank 48 via the pipe 47 and the fuel supply main pipe 45 . Gasoline is
The pressure is regulated by a pressure regulator 46 disposed at the rear end of the fuel supply main 45. A solenoid 42 is attached to the fuel supply main pipe 45, and each injector 7 changes the direction of its central axis by driving the common solenoid 42, as explained in FIG. Therefore, the direction of the central axis of each injector 7 is changed simultaneously.

FIG. 7 is an enlarged sectional view of the heater. A PTC (positive temperature) as a heating element is attached to the top plate 51 made of aluminum alloy through a conductive adhesive 52.
A perature efficient element 53 (made of ceramics such as barium titanate) is attached. The bottom plate 56 is made of heat-resistant resin (for example, epoxy or phenolic resin) or ceramics,
On top of that, a terminal plate 55, a contact 54 and a stud 57 are placed in this order.
The contact 54 is in elastic pressure contact with the PTC element 53. The top plate 51 and the bottom plate 56 each have one end facing downward to form an attachment part 8a to the cylinder head, and terminals 59A and 59B fixed in the attachment part 8a connect to the cable 58 and the top plate 51. are electrically connected to the terminal plate 55 and the PTC element 53, respectively. The heater 8 is configured as described above, and the heater 8 is attached to the inward flange 2b of the cylinder head 2 in FIG.
Fixed.

The energization and de-energization of the heater 8 and the energization and de-energization of the solenoid 42 are automatically performed based on the result of engine coolant temperature detection by a temperature sensor (for example, a thermocouple) not shown. Figures 8 to 11 described later
The same applies to the example of changing the mixed gas injection direction by introducing air. Instead of a solenoid, for example, a diaphragm valve of an air valve can be used to change the direction of the injector.

FIG. 8 is an enlarged partial sectional view similar to FIG. 4 (FIGS. 9 and 1) showing a mechanism for changing the mixed gas injection direction according to another example.
0), FIG. 9 is a cross-sectional view taken along line VIII-VIII of FIG.
10 is an enlarged sectional view taken along the line XX of FIG. 8. In this example, adapter 2 in Figures 4 and 5
An adapter 69 is used instead of 9. adapter 69
Through holes 69a are provided at six locations, and air ejection through holes 69d are provided diagonally downward toward an inclined surface 69b forming a truncated conical opening 69c. adapter 69
is supported by the injector support cylinder 5c via the packing 38 and two O-rings 39B, 39B. An air introduction pipe attachment part 62 is fixed to the injector support cylinder 5c,
A small diameter air introduction pipe 61 is attached to this. Further, on the extension thereof, a through hole 62a for blowing out air is provided in the air introduction pipe attachment portion 62, and a through hole 5e is provided in the injector support cylinder 5c.
However, the adapter 69 is provided with the same through hole 69d. The injector 7 does not swing and is fixed to the injector support cylinder 5c. The rest is the same as in the examples shown in FIGS. 4 and 5.

When the engine is warmed up, air introduced from the air introduction pipe 41 passes through the space 40 and six through holes 69d (arrows in FIG. 9), as in the examples shown in FIGS. 4 and 5.
The mixed gas MG2 mixed with the gasoline ejected from the nozzle 30 is injected in a direction whose central axis CL2 coincides with an extension of the central axis of the injector 7. At this time, air introduction from the small diameter air introduction hole 61 is stopped. The central axis CL2 points toward the center of the intake valve seat (11 in FIG. 1).

When the engine is cold, air is not introduced from the air introduction pipe 41, but air is introduced from the small diameter air introduction pipe 61. This introduced air has a high pressure because the introduction pipe 61 has a small diameter, and this high pressure air flows through the through holes 62a, 5e,
The water passes through the region 40a between the O-rings 39B, 39B in the space 40 and the through hole 69d in order, and is ejected from the opening 69e opening into the adapter inclined surface 69b to the truncated conical opening 69c. This ejected air swirls along the inclined surface 69b and mixes with gasoline ejected from the nozzle 30, and the injection center line CL1 of this mixed gas MG1 is displaced by an angle α with respect to the central axis extension CL2 of the injector 7. The heater 8 shown in FIG. 7 is arranged in the direction of the center line CL1.

FIG. 11 is a fluid circuit diagram showing the air introduction path to the adapter 69. At the tip of the main air supply pipe 63, a solenoid valve 64 connects the air introduction pipe 41 and the small diameter air introduction pipe 61.
Either route is selected. When the engine is warmed up, air is introduced into the adapter 69 via the air introduction pipe 41, and the mixed gas MG2 shown in FIG. 8 is injected. When the engine is cold, high-pressure air is introduced into the adapter 69 via the small-diameter air introduction pipe 61, and the mixed gas MG1 shown in FIG. 8 is injected.

In this example as well, the mixed gas injection direction is shifted to face the heater or the intake valve seat depending on when the engine is cold or warm, so as in the examples shown in FIGS. 2 to 6, The mixed gas is always combusted under ideal conditions, ensuring ideal engine operation. Furthermore, the only movable part required to change the mixed gas injection direction is inside the electromagnetic valve, and the injector is fixed, so there is an advantage that the operation is simple and there is less chance of failure.

Although the above embodiment is an example of a four-stroke engine, the present invention is equally applicable to a rotary piston engine. The intake air can also be oxygen-enriched air. Furthermore, the shape, structure, material, etc. of the above-mentioned heater may be changed in various ways, and the heating element used may also be other than the PTC element (
In short, any electrical heater element is sufficient).

[0034]

[Effects of the Invention] The fuel supply device for an internal combustion engine according to the present invention is constructed so that the direction of fuel injection can be selected either toward the fuel heating means or toward another direction. Therefore, when selecting whether or not to use the fuel heating means in accordance with the situation of the internal combustion engine, the injected fuel will not be undesirably influenced by the fuel heating means when the fuel heating means is not in use. As a result, the injected fuel can ensure ideal combustion conditions both when the fuel heating means is used and when it is not used, and ideal driving of the internal combustion engine is always guaranteed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the vicinity of a combustion chamber of a gasoline engine according to an embodiment.

FIG. 2 is a schematic front view (partially in section) showing how to change the mixed gas ejection direction of the fuel injector.

FIG. 3 is an enlarged cross-sectional view of the fuel injector.

4 is an enlarged cross-sectional view of the tip portion of the fuel injector of FIG. 2 and its surroundings (cross-sectional view taken along the line IV-IV of FIG. 5);

FIG. 5 is an enlarged sectional view taken along the line V-V in FIG. 4;

6 is a schematic diagram showing an overview of gasoline supply to the fuel injector of FIGS. 5 and 6. FIG.

FIG. 7 is an enlarged sectional view of a fuel heating device (heater).

FIG. 8 is an enlarged sectional view of the tip portion and its surroundings of a fuel injector according to another embodiment (VIII-III in FIGS. 9 and 10).
VIII line sectional view).

9 is an enlarged sectional view taken along the line IX-IX in FIG. 8. FIG.

FIG. 10 is an enlarged sectional view taken along the line XX in FIG. 8;

11 is a fluid circuit diagram showing an air introduction path to the adapter of FIGS. 8 to 10. FIG.

FIG. 12 is a schematic cross-sectional view of the carburetor.

FIG. 13 is a partial cross-sectional view of a conventional gasoline engine equipped with a fuel injector and a fuel heating device (heater).

[Explanation of symbols]

2 Cylinder head 5 Intake manifold 5a Intake manifold branch pipe 5c Injector support cylinder 5d, 5e, 29a, 62e, 69a, 69d Through hole 7 Injector 8 Heater 9 Intake valve 11 Intake valve seat 17 Spark plug 18 Combustion chamber 29, 69 Adapter 30 Nozzle 41 Air introduction pipe 42 Solenoid 45 Main fuel supply pipe 61 Small diameter air introduction pipe 63 Main air supply pipe 64 Solenoid valve CL Central axis of the injector

Claims (1)

[Claims] 1. A fuel injection device comprising a fuel injection means and a fuel heating means for heating the fuel injected from the fuel injection means, the injection direction of the fuel being directed toward the fuel heating means; A fuel supply device for an internal combustion engine configured to be selected from both directions.