JP2001065386A - Direct fuel injection engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the bad influence of the vibration of engine on a fuel pressure sensor for preventing the impairing of the starting performance by mounting the fuel pressure sensor capable of detecting the pressure in a high- pressure fuel path for supplying the high-pressure fuel to an injector, on an engine through a damping material. SOLUTION: The fuel in a paper separator tank is preloaded by a fuel preloading pump, further pressurized by a high-pressure fuel pump to be supplied to a fuel supply rail 33 (33a, 33b), and supplied to injectors 13 of every cylinders #1-#6. On this occasion, a sensor box 97 is fixed by a bolt 98 to a lower part of an injector driver box supported by an electrical equipment box 77 through two kinds of damping materials having the spring constants different from each other. A lower part of the fuel supply rail 33b is connected to one end of the sensor box 97 through a high-pressure hose 99, and a fuel pressure sensor 47 is mounted on the other end of the sensor box 97. Whereby the fuel sensor 47 can be prevented from being affected by the vibration of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of preventing in-cylinder fuel injection type engines from vibrating a fuel pressure sensor for detecting the pressure of high-pressure fuel.

[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. A fuel pressure sensor for detecting the pressure of the high-pressure fuel is provided in the high-pressure fuel pipe.
This fuel pressure sensor is mainly used for correcting the fuel injection amount at the time of starting when the fuel pressure does not rise to a predetermined value.

[0003]

The fuel pressure sensor currently used is composed of a minute strain gauge, a circuit for signal amplification and signal conversion, and the like, and does not always have a structure resistant to vibration. On the other hand, high-pressure fuel pipes are mainly metal pipes and are rigidly attached directly to the engine side, because it is necessary to ensure rigidity and positioning accuracy.
The engine vibration is transmitted to the high-pressure fuel pipe, and it is difficult to dampen the fuel pressure sensor. However,
If the fuel pressure sensor becomes abnormal due to the influence of vibration, it becomes impossible to start the fuel until the fuel pressure rises to a predetermined value (a large number of crankings is required). .

The present invention solves the above-mentioned conventional problems and problems, and provides an in-cylinder fuel injection type engine which prevents an adverse effect on a fuel pressure sensor due to engine vibration and does not cause deterioration of startability. The purpose is to do.

[0005]

According to one 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 through a high pressure fuel passage. The fuel pressure sensor for detecting the pressure in the high-pressure fuel passage is attached to the engine via a vibration isolator, and the invention according to claim 2 is the invention according to claim 1, wherein the engine is connected to the engine via a vibration isolator. The electrical component box is attached to the electrical component box, and a fuel pressure sensor is attached to the electrical component box. The invention according to claim 3, wherein the fuel pressure sensor is attached to the mounting surface of the high-pressure fuel passage according to claim 1, It is characterized by being attached by a floating structure via a.

[0006]

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 example of an in-cylinder fuel injection type engine to which the present invention is applied, wherein FIG. 1A is a plan view of the engine, and FIG.
FIG. 3C is a longitudinal sectional view taken along the line BB, FIG. 3C is a side view of the outboard motor, and FIG. 3D is a configuration diagram of a fuel supply system.

An outboard motor 1 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 a 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.

The ECU (electronic control unit) 42 receives detection signals from various sensors indicating the operating state of the engine 2 and the state of the outboard motor 1. 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, various detection signals such as 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 processes the detection signals of these sensors based on the control map, and transmits the control signals to the injector driver 42a, the injector 13, the ignition 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, 70 is a starter motor, 71 is a belt tensioner, and 72 is a silencer.

FIG. 3 is a view showing one embodiment of the present invention as viewed from the Y direction in FIG. 2, and FIG. 4 is a longitudinal sectional 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. The fuel supply / discharge unit 67 is connected to a pair of left and right fuel supply rails 33a and 33b via a connector 69 and a high-pressure hose 49 wound with a tube 49a having flame resistance. The injector 13 is fixed to the cylinder head 8 by a fixture 76. In FIG. 3, notches 33k are formed in the fuel supply rails 33a and 33b, and the notches 33k provide a tool escape when the fixing bracket 33m of the injector 13 is fastened with the bolts 33h, so that good assembly is performed. Nature is secured.

On the wall of the cylinder body 7, V banks B1,
An electrical component box 77 is mounted between B2. The electrical component box 77 includes an ECU box 77a and an injector driver box 77b, and each of the boxes contains the circuit components of the ECU 42 and the injector driver 42a shown in FIG. A mounting member 79 is fixed to the cylinder body 7 by a bolt 91 via a first vibration isolator 90, and an ECU box 77 a is fixed to the mounting member 79 by a bolt 92. A boss 79 a is formed on the mounting member 79.
The injector driver box 77b is fixed to a by a bolt 94 via a second vibration isolator 93. In addition, a bolt 9 is provided in the injector driver box 77b.
5, a cooling fin 96 is attached. A sensor box 97 according to the present invention is fixed to a lower portion of the injector driver box 77b by bolts 98. One end of the sensor box 97 is connected to a lower portion of the fuel supply rail 33b via a high-pressure hose 99, and At the other end, a fuel pressure sensor 47 is mounted.

In this embodiment, the first vibration isolator 90
The first vibration isolator 90 is made of a harder material to reduce high-frequency vibration from the engine side, and the second vibration isolator 93 is made different. Using a material softer than the first vibration isolator 90
Relatively low frequency vibration from the CU box 77a can be reduced. For example, when the vibration of the engine is about 30G, the vibration in the ECU box 77a is reduced to about 8G, and the vibration in the injector driver box 77b is reduced to 1G.
Vibration can be effectively reduced to about G, and vibration of the electrical component box 77 and the fuel pressure sensor 47 can be suppressed. In this embodiment, the sensor box 97 may be directly fixed to the cylinder body (vibration member) 7 via a vibration isolator.

5 to 7 show another embodiment of the present invention. FIG. 5 is a side view of FIG. 3 viewed from the X direction, FIG. 6 is a plan view of FIG. 5, and FIG. It is sectional drawing which follows the -A line. In the present embodiment, a fuel pressure sensor 47 is provided at a position communicating with the high-pressure fuel passage 34 of the fuel supply / discharge unit 67. The fuel pressure sensor 47 is not limited to the high-pressure fuel passage 34 of the fuel supply / discharge unit 67, but may be at any position as long as it can communicate with the high-pressure fuel passage. Also,
5 and 6 so that the injector 13 does not fall off the fuel supply rails 33a and 33b before assembly such as during transportation.
The clip 13d is provided as shown in the figure, and the clip 13d prevents the injector 13 from rotating (positioning).
Also, the detachability of the injector 13 can be improved. Further, a rack-shaped portion 13e integrally formed with the clip 13d is
This is for clamping the lead wire, and prevents damage caused by hooking of the lead wire.

In FIG. 7, the fuel pressure sensor 47 comprises a sensor portion 47a, a flange portion 47b, a sensor main body 47c, and a connection portion 47d. The mounting surface 100 of the fuel supply / discharge unit 67 facing the high pressure fuel passage 34 has a sensor Insertion hole 67
a, a sensor locking portion 67b and two bolt holes 67c are formed, the sensor portion 47a of the fuel pressure sensor 47 is inserted into the sensor insertion hole 67a via an O-ring 47e, and the inner surface of the flange 47a is formed in the sensor locking portion 67b. Locked. The collar 101 is provided at a position facing the bolt hole 67c. On the mounting surface 100, a metal plate 102 is provided so as to penetrate the sensor main body 47c and the collar 101, and is provided on the outside of the metal plate 102 in the same manner as the anti-vibration made of an elastic member through the sensor main body 47c and the collar 101. A material 103 is provided. And color 101
A cover member 104 for pressing is provided, and the cover member 104 is fixed by screwing a bolt 106 through a washer 105.

In the vibration damping structure according to the present embodiment having the above-described structure, a high fuel pressure is generated in the high-pressure fuel passage 34 when the engine is started, and a force for pressing the sensor portion 47a works. Since a slight gap is generated between the plate 102 and the mounting surface 100, a floating structure (buoyancy) in which the fuel pressure sensor 47 is fixed to the fuel supply / discharge unit 67, which is a vibration member, via the vibration isolator 103. When a vibration pressure is applied to the fuel pressure sensor 47, the vibration is reduced by the vibration isolator 103 via the cover member 104, so that the vibration can be reduced.

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.

[0022]

As is apparent from the above description, according to the first aspect of the present invention, it is possible to prevent the fuel pressure sensor from being adversely affected by the engine vibration and to prevent the startability from deteriorating.
According to the second aspect of the present invention, it is possible to mount the apparatus at low cost by utilizing the existing vibration isolating structure, and according to the third aspect of the present invention, it is possible to reliably reduce the vibration by the floating structure.

[Brief description of the drawings]

FIG. 1 is a schematic view of an outboard motor showing an example of an in-cylinder fuel injection engine to which the present invention is applied, wherein FIG. 1A is a plan view of the engine, and FIG. FIG. 4C is a longitudinal sectional view taken along line BB, FIG. 4C is a side view of the outboard motor, and FIG. 4D is a configuration diagram of a fuel supply system.

FIG. 2 is a plan view of the outboard motor of FIG.

FIG. 3 is a view showing one embodiment of the present invention and viewed from a Y direction in FIG. 2;

FIG. 4 is a longitudinal sectional view of FIG. 3;

FIG. 5 is a side view showing another embodiment of the present invention and viewed from an X direction in FIG. 3;

FIG. 6 is a plan view of FIG. 5;

FIG. 7 is a sectional view taken along the line AA in FIG.

[Explanation of symbols]

 7 ... Cylinder body 13 ... Injector 32 ... High pressure fuel pump 34 ... High pressure fuel passage 47 ... Fuel pressure sensor 77 ... Electrical component box 90,93,103 ... Vibration insulator

Claims (3)

[Claims] An in-cylinder fuel injection engine that supplies high-pressure fuel pressurized by a high-pressure fuel pump to an injector through a high-pressure fuel passage, a fuel pressure sensor for detecting a pressure in the high-pressure fuel passage is provided with a vibration-proof material. An in-cylinder fuel injection engine, which is attached to the engine via a fuel injection valve. 2. The in-cylinder fuel injection engine according to claim 1, wherein an electric component box is attached to the engine via a vibration isolator, and a fuel pressure sensor is attached to the electric component box. 3. The in-cylinder fuel injection engine according to claim 1, wherein a fuel pressure sensor is mounted on the mounting surface of the high-pressure fuel passage by a floating structure via a vibration isolator.