JP2001065426A - Cylinder fuel injection engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce pulsation in a high pressure fuel piping, and correctly control an air-fuel ratio by connecting a high pressure hose having contractility to a part of the high pressure fuel piping. SOLUTION: A fuel supplying/delivering unit 67 and a pressure regulating valve 35 are connected to each other through a joint 74 and a high pressure fuel passage 75. The fuel supplying/delivering unit 67 is connected to a pair of right and left fuel supplying rails 33a, 33b through a connecting tool 67 and a high pressure hose 49 around which a flame-resistant tube is wound. A high pressure hose 76 is connected to a dead end part disposed on a lower part of the fuel supplying rail 33b through a connecting tool 77. Even if high fuel hoses 49, 76 in which metallic pipings are used in many cases are used, fuel pressure pulsation can be reduced, and a fuel injection quantity is controlled with high accuracy. It is thus possible to correctly control an air-fuel ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention belongs to the technical field of preventing pulsation of high-pressure fuel in a cylinder fuel injection type engine.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. H11-18228
As shown in Japanese Patent Publication No. 2 (1993), an air-fuel ratio sensor for detecting an air-fuel ratio of exhaust gas after combustion is provided, and a fuel injection amount to be injected into a cylinder is feedback-controlled so as to attain a target air-fuel ratio. An in-cylinder fuel injection engine designed to improve fuel efficiency is known. In this engine, a state in which fuel is pressurized by a high-pressure pump is created, and the fuel injection amount is calculated by controlling the valve opening time of the injector. On the other hand, when the high-pressure pump or the injector itself operates, it generates pulsation in the fuel and lowers the accuracy of the fuel injection amount. Therefore, it is desired to minimize the generation of pulsation.

[0003]

However, in recent years, fuel pressure has increased with the progress of direct injection of engines, and metallization of high-pressure fuel pipes has progressed. The effect of the pulsation on the accuracy of the fuel injection amount has become remarkable. Specific inconveniences include a shift in the injection timing due to a delay in the opening of the injector and a decrease in the actual injection amount. As a result, there is a problem that accurate air-fuel ratio control cannot be performed.

[0004] In particular, in an engine such as an outboard motor in which a crankshaft is arranged in a vertical direction, Japanese Patent Application Laid-Open No. H11-1822 is disclosed.
As disclosed in Japanese Patent Publication No. 82, the high pressure fuel pump and the high pressure regulating valve are arranged above the fuel supply rail which is a fuel pipe because the high pressure fuel pump is driven by rotation of the crankshaft. Since the lower end of the rail becomes a reflection end of the fuel pulsation and the pulsation increases, the injector closer to the lower end of the fuel supply rail is affected by the fuel pulsation in the pipe. On the other hand, the fuel injection amount is calculated on the assumption that the fuel pressure is constant, and the air-fuel ratio is controlled by calculating the fuel injection amount during the energization time.However, when the fuel pressure changes, the fuel injection amount also changes. Accurate air-fuel ratio control is not possible,
There is a problem that the combustion becomes worse.

An object of the present invention is to solve the above-mentioned conventional problems and problems, and to provide an in-cylinder fuel injection engine capable of reducing pulsation in a high-pressure fuel pipe and performing accurate air-fuel ratio control. With the goal.

[0006]

According to a first aspect of the present invention, there is provided an in-cylinder fuel injection engine for supplying high pressure fuel pressurized by a high pressure fuel pump to an injector via a high pressure fuel pipe. Wherein a high-pressure hose having contractility is connected to a part of the high-pressure fuel pipe. In the invention according to claim 2, a high-pressure hose is connected to a dead end of the high-pressure fuel pipe in claim 1. According to a third aspect of the present invention, in the first aspect, a high-pressure hose is connected between a fuel supply rail to which the injector is attached and a high-pressure fuel pump. The high-pressure hose according to any one of claims 1 to 3, wherein the high-pressure hose has an inner tube made of an elastic material, a resin fiber layer laminated on an outer periphery of the inner tube, and a protective layer laminated on an outer periphery of the resin fiber layer. According to a fifth aspect of the present invention, in the first aspect, the engine is arranged in two rows such that a crankshaft is vertically arranged and a plurality of cylinders form a V bank. The rails are fixed to the cylinder heads in each row, and a high-pressure hose is connected to a lower portion of at least one of the fuel supply rails.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of an outboard motor showing one embodiment of an in-cylinder fuel injection engine of the present invention,
Figure (A) is a plan view of the engine, and Figure (B) is B in Figure (A).
FIG. 3C is a longitudinal sectional view taken along the line B, FIG. 3C is a side view of the outboard motor, and FIG. 3D is a configuration diagram of a fuel supply system.

Reference numeral 1 denotes an outboard motor, which includes an engine 2 on which a crankshaft 10 is mounted vertically, a guide exhaust 3 connected to a lower end surface of the engine 2 and supporting the engine 2, and a guide exhaust 3. It comprises an upper case 4, a lower case 5, and a propeller 6 connected to the lower end surface.
The engine 2 is an in-cylinder injection V-type six-cylinder two-stroke engine, and is disposed horizontally and vertically in two rows so that six cylinders # 1 to # 6 form a V bank in plan view. The cylinder head 8 is connected and fixed to the cylinder body 7 thus formed. A cooling water pump 18 driven by an engine is provided in the upper case 4, and circulates cooling water through the cooling water intake port 5 a formed in the lower case 5 through the engine 2 as shown by an arrow in the drawing, and the vicinity of the propeller 6. To be discharged from

A piston 1 is provided in each of the cylinders # 1 to # 6.
1 are slidably fitted and arranged, and each piston 11 is connected to the crankshaft 10. The cylinder head 8 is provided with a solenoid open / close type injector (fuel injection valve) 13 and an ignition plug 14 that are opened and closed by magnetic force. Each of the cylinders # 1 to # 6 is connected to the crank chamber 12 by a scavenging port (not shown).
The exhaust port 15 is connected to # 6. FIG.
The exhaust port 15 of the left bank in FIG.
6, the exhaust port 15 of the right bank is
Has been joined. In the crankcase 12 of the engine 2,
An intake passage 19 branching from the intake manifold is connected to the intake passage 19.
An oil pump 2 for supplying and lubricating oil into the engine is provided downstream of the reed valve 20.
1, a throttle valve 22 for adjusting the amount of intake air is provided upstream of the reed valve 20.

As shown in FIG. 1 (D), the fuel in a fuel tank 23 installed on the hull side is passed through a fuel filter 26 by a manually operated first low-pressure fuel pump 25, and the fuel is supplied to the second outboard motor side. 2 is sent to the low-pressure fuel pump 27. The second low-pressure fuel pump 27 is a diaphragm pump driven by pulse pressure in the crank chamber 12 of the engine 2 and sends fuel to a vapor separator tank 29 which is a fuel tank having a gas-liquid separation function. A fuel precompression pump 30 driven by an electric motor is provided in the vapor separator tank 29, and pressurizes the fuel and sends it to a high pressure fuel pump 32 via a precompression pipe 31. The discharge side of the high-pressure fuel pump 32 is provided with fuel supply rails 33a vertically arranged along the right bank cylinders # 1, # 3, # 5 and the left bank cylinders # 2, # 4, # 6, respectively. 33b is connected to the vapor separator tank 29 via a high-pressure pressure regulating valve 35, a fuel cooler 36, and a return pipe 37 while being connected to the vapor separator tank 29 via a high-pressure hose 49. Further, a preload pressure adjusting valve 39 is provided between the preload pipe 31 and the vapor separator tank 29. High pressure fuel pump 32
Is driven by the pump drive unit 40. The pump drive unit 40 is connected to the crankshaft 10 via a belt 41.

The oil pump 21 for lubricating the engine is a pump driven by the rotation of the crankshaft 10. The oil pump 21 is provided in the intake passage 19 through a main tank 51 provided on the engine side from a sub tank 50 provided on the hull side. Supply oil to The oil in the main tank 51 is configured to be supplied to the vapor separator tank 29 via a filter 52, a premix oil pump 53, and a check valve 54. As the premix oil pump 53, a pump driven by an electromagnetic solenoid or a pump driven by an electric motor is used.

Detection signals from various sensors indicating the operating state of the engine 2 and the state of the outboard motor 1 are input to an ECU (electronic control unit) 42. For example, an engine speed sensor 43 that detects a rotation angle (speed) of the crankshaft 10;
An intake air temperature sensor 44 for detecting the temperature in the intake passage 19, a throttle opening sensor 45 for detecting the opening of the throttle valve 22, an air-fuel ratio sensor 46 for detecting the air-fuel ratio in the uppermost cylinder # 1, a high-pressure fuel A fuel pressure sensor 47 for detecting the pressure in the pipe 34, a cooling water temperature sensor 48 for detecting the temperature of the cooling water of the engine, a water detection sensor 55 for detecting the amount of water separated by the fuel filter 26, and an exhaust pressure sensor for detecting the exhaust pressure. 38, detection signals from an oil level sensor 56 for detecting the amount of oil in the oil tank 51, an outside air temperature sensor 57, and a trim sensor 28 for detecting the attitude of the engine are input. The ECU 42 performs an arithmetic process on the detection signals of these sensors based on the control map, and outputs the control signals to the injector 1.
3. Transmission to the spark plug 14, the preload fuel pump 30, and the premix oil pump 53.

The operation of the engine having the above configuration will be described. The fuel in the vapor separator tank 29 is
For example, 3 to 10 kg / cm ² by the fuel preload pump 30
The pre-pressurized and pressurized fuel is supplied to the high pressure fuel pump 3
2, the pressure of the fuel is increased to about 50 to 100 kg / cm ² or more.
The excess fuel exceeding the set pressure is returned to the vapor separator tank 29, and only the necessary high-pressure fuel is supplied to the fuel supply rail 33 and supplied to the injectors 13 mounted on the cylinders # 1 to # 6. The oil pump 21 is driven by the rotation of the crankshaft 10 and supplies oil to the sub tank 5.
0, supply from the main tank 51 into the intake passage 19 to lubricate the inside of the engine.

FIG. 2 is a plan view of the outboard motor of FIG. In the following description, the same components as those in the above-described drawings may be assigned the same reference numerals and description thereof may be omitted. A flywheel 73 is fixed to the crankshaft 10, and a drive pulley 60 is attached to an upper portion thereof, that is, an upper end of the crankshaft 10,
A driven pulley 62 is provided on a rotating shaft 61 of the pump drive unit 40, and the driven pulley 60 and the driven pulley 62
Is provided with a drive belt 41. The high-pressure fuel pump 32 is attached to the pump drive unit 40 by bolts 59. Thus, the rotation of the crankshaft 10 is transmitted to the rotation shaft 61 via the drive belt 41, and drives the high-pressure fuel pump 32.

A mounting stay 63 is fixed to the cylinder body 7, and the pump driving unit 40 is connected to the mounting stay 6.
3 and three bolts 64, 65, 6 on the cylinder body 7.
6 attached. Also, the fuel supply rail 3
The fuel injection valves 3a and 33b are fixed to the cylinder head 8 by bolts, and the fuel injection valves 13 are connected to fuel supply rails 33a and 33b. The high-pressure fuel pump 32 has a fuel supply / discharge unit 67, and has two outlets of the fuel supply / discharge unit 67 and left and right fuel supply rails 33.
a and 33b are a connector 69 and a high-pressure hose 4 respectively.
9. In the drawing, 1a is an engine cover, 70 is a starter motor, 71 is a belt tensioner, 72 is a silencer, and 75 is a throttle body.

FIG. 3 is a view seen from the Y direction in FIG. 2, and FIG. 4 is a plan view of FIG. The fuel supply / discharge unit 67 and the pressure regulating valve 35 are connected via a joint 74 and a high-pressure fuel passage 75. Further, the fuel supply / discharge unit 67 is provided with the connecting device 6.
9. High-pressure hose 4 wrapped around a flame-resistant tube 90
9 are connected to a pair of left and right fuel supply rails 33a, 33b. And one fuel supply rail 33b
A high pressure hose 76 is connected to the bottom of the
7 are connected. The high-pressure hose 76 may be provided below the other fuel supply rail 33a, or may be provided on both fuel supply rails.

In FIG. 3, the fuel supply rails 33a, 33
3b, a notch 91 is formed.
In the case of the first embodiment, when the fixing bracket 79 of the injector 13 is fastened with the bolt 92, the tool escapes to ensure good assemblability. Also, before assembling, for example, during transportation, the fuel supply rails 33a,
4b so that the injector 13 does not fall out of FIG.
The clip 93 is provided as shown in FIG. 3 and also serves as a detent (positioning) of the injector 13 so that the injector 13 can be easily attached and detached. Further, a rack-like portion 93a integrally formed with the clip 93 is for clamping a lead wire of each injector 13, and prevents damage due to hooking of the lead wire.

FIG. 5 shows the high pressure hoses 49 and 76, FIG. 5 (A) is a side view, and FIG. 5 (B) is a sectional view.
The high-pressure hose 49 includes an inner tube 49a made of an elastic material such as rubber or resin, a resin fiber layer 49b having elasticity covering the outer periphery of the inner tube 49a, and a rubber laminated on the outer periphery of the resin fiber layer 49b. And a protection layer 49c. Since this high-pressure hose has an appropriate contractibility and is excellent in strength, the pulsation of the high-pressure fuel can be significantly reduced by the contraction of the hose itself. FIG. 6 shows the results of the experiment, where # 2, # 4,
It has been found that the pulsation width of the injector on the # 6 cylinder side is significantly reduced in the case of the present invention (lower stage) compared to the conventional case (upper stage).

FIG. 7 shows another embodiment of the present invention.
FIG. The embodiment of FIG.
Extends horizontally from one fuel supply rail 33b, but in the present embodiment, the fuel supply rail 33b
The example which extended in the vertical direction inside the inside is shown.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made. For example, in the above embodiment, an example in which the invention is applied to an outboard motor is described, but the invention is also applicable to an automobile. Further, the present invention is not limited to a two-cycle engine, and is applicable to a four-cycle engine.
Further, the present invention is not limited to the V-type engine, but can be applied to an in-line engine.

[0021]

As is apparent from the above description, according to the first to fourth aspects of the present invention, fuel pressure pulsation can be reduced even when a high-pressure fuel pipe using a large number of metal pipes is used.
The fuel injection amount can be controlled with high accuracy, and accurate air-fuel ratio control can be performed. According to the invention as set forth in claim 5, a plurality of cylinders form a V bank with the crankshaft arranged vertically. It is arranged in two rows and can be suitably adopted for the engine.

[Brief description of the drawings]

FIG. 1 is a schematic view of an outboard motor showing one embodiment of an in-cylinder fuel injection engine according to the present invention, wherein FIG. 1 (A) is a plan view of the engine, and FIG. Longitudinal sectional view along line B,
FIG. (C) is a side view of the outboard motor, and FIG. (D) is a configuration diagram of the fuel supply system.

FIG. 2 is a plan view of the engine of FIG.

FIG. 3 is a diagram viewed from a Y direction in FIG. 2;

FIG. 4 is a plan view of FIG. 3;

5 shows the high pressure hose and the pulsation damper, FIG.
5A is a side view, and FIG. 5B is a cross-sectional view.

FIG. 6 is a diagram for explaining an effect of the present invention.

FIG. 7 is a view similar to FIG. 3, showing another embodiment of the present invention.

[Explanation of symbols]

 8 ... Cylinder head 10 ... Crank shaft 13 ... Fuel injection valve 32 ... High pressure fuel pump 33a, 33b ... Fuel supply rail 49, 76 ... High pressure hose

Claims (5)

[Claims] An in-cylinder fuel injection type engine for supplying high-pressure fuel pressurized by a high-pressure fuel pump to an injector via a high-pressure fuel pipe, a high-pressure hose having contractibility is connected to a part of the high-pressure fuel pipe. An in-cylinder fuel injection engine characterized in that: 2. The in-cylinder fuel injection engine according to claim 1, wherein a high pressure hose is connected to a dead end of said high pressure fuel pipe. 3. The in-cylinder fuel injection engine according to claim 1, wherein a high-pressure hose is connected between a fuel supply rail on which the injector is mounted and a high-pressure fuel pump. 4. The high-pressure hose comprises an inner tube made of an elastic material, a resin fiber layer laminated on an outer periphery of the inner tube, and a protective layer laminated on an outer periphery of the resin fiber layer. 4. The in-cylinder fuel injection engine according to claim 1, wherein: 5. The fuel supply system according to claim 1, wherein the engine is arranged in two rows such that a crankshaft is vertically arranged and a plurality of cylinders form a V bank, and the fuel supply rails are fixed to cylinder heads of each row. 5. The in-cylinder fuel injection engine according to claim 1, wherein a high-pressure hose is connected to a lower portion of at least one of the rails.