JP2001207926A - Pressure regulating device and fuel supply control device of internal combustion engine furnished with pressure regulating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure regulating device compact and capable of speedily regulating fluid pressure in high precision. SOLUTION: A movable retainer 43b provided on a nut 43 of a ball screw 41 is displaced in a direction of an axis L1 of a spring 39 and spring force is regulated when an electric motor 48 to be controlled by an ECU is driven to rotate by the ball spring 41 and fluid pressure is regulated on a pressure regulating device 20 to regulate fluid pressure as a valve element 32 provided on a diaphragm 25 to divide a fluid chamber 28 and a spring chamber 29 opens and closes an outflow port 36.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a pressure regulator for regulating the pressure of a fluid in a fluid supply passage and a pressure regulator for regulating the fuel pressure in a fuel supply passage to a fuel injection valve of an internal combustion engine. The present invention relates to a fuel supply control device for an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, the amount of fuel injected from a fuel injection valve in an internal combustion engine is controlled by the opening time of the fuel injection valve. Therefore, the fuel pressure in a fuel supply passage from the fuel pump to the fuel injection valve is adjusted. A pressure adjusting device is provided. However, if the fuel pressure is always adjusted to a constant fuel pressure with respect to the pressure of the intake passage facing the fuel injection valve, the required fuel amount that is increased or decreased according to the engine operating state is not injected at an appropriate time in relation to the intake stroke. For this reason, techniques for changing the fuel pressure in accordance with the operating state of the engine have been proposed.

[0003] For example, in a fuel supply control device for an internal combustion engine (hereinafter referred to as "the former") disclosed in Japanese Patent No. 2513588, the supply of fuel to the upstream side of a fuel injection valve is completed so that fuel injection is completed by the end of an intake stroke. In order to adjust the fuel pressure in the passage, a fuel pressure control valve is provided in the return passage downstream of the fuel injection valve to control the passage area of the return passage according to the engine speed, the absolute pressure in the intake pipe and the oxygen concentration of the exhaust gas. Can be The fuel pressure control valve comprising an electromagnetic valve is provided with a plunger slidable in a plunger fitting hole. With this plunger, the higher the engine speed and the higher the absolute pressure in the intake pipe, the more the oxygen concentration is reduced. The larger the correction value of the corresponding air-fuel ratio is, the smaller the passage area of the return passage is,
As a result, the fuel pressure on the fuel injection valve is increased, and the required fuel amount is injected from the fuel injection valve by the end of the intake stroke.

A pressure regulator (hereinafter referred to as "the latter") of a fuel injection device disclosed in Japanese Patent Laid-Open No. 5-79431 is provided in a fuel chamber and a pressure chamber divided by a partition, and in the partition. A valve body for opening and closing a fuel outflow passage of the fuel chamber, a spring provided in the pressure chamber to press the partition toward the fuel chamber, and a spring force adjusting means for variably adjusting the spring force of the spring. I have. The spring force adjusting means includes a step motor and a locking member locked to one end of the spring, and the linear reciprocating motion of the locking member adjusts the spring force during operation of the engine, thereby increasing the fuel pressure or increasing the fuel pressure. As a result, the fuel injection characteristic is variably controlled.

[0005]

By the way, in the former,
Since the adjustment of the fuel pressure is performed by the plunger sliding in the plunger fitting hole, in order to quickly perform high-precision fuel pressure adjustment, the sliding distance of the plunger is increased to control the passage. The fuel pressure control valve tends to be large because the difference between the maximum value and the minimum value of the area must be increased and the plunger must be quickly moved to overcome the frictional resistance between the plunger fitting hole and the plunger. Met.

Further, in the latter, since the rotational motion of the rotor of the step motor is converted into a linear reciprocating motion by a feed screw mechanism provided between the rotor and the locking member, the fuel pressure is quickly adjusted. However, there is a need for a motor having a large output capable of moving the locking member overcoming the frictional resistance of the meshing portion between the rotor and the locking member, and the pressure regulator may be increased in size.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and the inventions of claims 1 to 5 are compact and can quickly perform high-precision fluid pressure adjustment. Another object of the present invention is to provide a pressure adjusting device for adjusting a fuel pressure to a fuel injection valve of an internal combustion engine. It is an object of the present invention to suppress the adhesion of the fuel to the wall surface of the intake passage of the fuel, thereby improving the exhaust emission and the engine operation performance.

[0008]

Means for Solving the Problems and Effects of the Invention The invention according to claim 1 of the present application provides a displaceable partition for partitioning a fluid chamber and a spring chamber, an outlet provided in the fluid chamber, and a fluid. An inflow port communicating with the supply passage, a valve body provided in the partition wall for opening and closing the outflow port, and a spring provided in the spring chamber to apply a spring force to the partition wall in a valve closing direction of the valve body. The fluid supply by opening and closing the outlet according to the valve closing force of the valve body by the spring force and the valve opening force of the valve body by the pressure of the fluid in the fluid chamber acting on the partition wall. In a pressure adjusting device for adjusting the pressure of the fluid in the passage, adjusting means for adjusting the spring force is provided, the adjusting means includes a movable member abutting on the spring, a ball screw for displacing the movable member, Driving the ball screw And dynamic motor, and control means for controlling the rotation of the electric motor, the movable member by the ball screw is a pressure regulator spring force is adjusted by displacement.

According to the first aspect of the present invention, the movable member for adjusting the spring force for adjusting the fuel pressure by contacting the spring is displaced by the ball screw having a small frictional resistance. Therefore, the output of the electric motor that overcomes the frictional resistance and displaces the movable member may be small, a small-sized electric motor can be used, and the pressure regulator becomes compact. Furthermore, by using the ball screw, the position of the movable member can be set with high accuracy, and the movable member can be quickly displaced, so that the pressure can be adjusted with high accuracy and speed.

According to a second aspect of the present invention, in the pressure adjusting device according to the first aspect, the spring is a coil spring, a screw shaft of the ball screw is rotationally driven by the electric motor, and an axial direction of the coil spring is provided. The nut of the ball screw displaced in the coil spring is arranged inside the coil spring to constitute a spring guide,
Further, the nut is provided with the movable member.

According to the second aspect of the present invention, since the nut of the ball screw is arranged inside the coil spring to constitute a spring guide, the coil spring is prevented from falling down and the spring force is adjusted. The linearity of the change in the spring force can be maintained, and the pressure can be adjusted with high accuracy. In addition, since the movable member is provided on the nut disposed inside the coil spring, the axis of the screw shaft of the pressure adjusting device is provided. The dimension in the direction can be reduced, and the pressure regulator can be made compact.

According to a third aspect of the present invention, in the pressure adjusting device of the second aspect, the electric motor is disposed in parallel with the screw shaft, and rotation of the electric motor causes the spring chamber to rotate. This is transmitted to the screw shaft via a gear mechanism arranged along the end face of the case to be formed.

According to the third aspect of the present invention, the electric motor is arranged in parallel with the screw shaft, and the gear mechanism for transmitting the rotation of the electric motor to the screw shaft extends along the end face of the case forming the spring chamber. Because it is arranged, the axial dimension of the screw shaft of the pressure adjusting device can be reduced,
Also in this respect, the pressure regulator can be made compact.

According to a fourth aspect of the present invention, in the pressure adjusting device according to any one of the first to third aspects, a position detecting means for detecting a position of the movable member which is displaced is provided. The control means controls the rotation of the electric motor to feedback-control the position of the movable member to a target position based on the detection signal of the position detection means.

According to the fourth aspect of the invention, the position of the movable member, that is, the degree of adjustment of the spring force of the spring is detected by the position detecting means, and the movable member is moved in accordance with the target fluid pressure. Since feedback control is performed to the set target position, pressure adjustment with higher accuracy can be performed.

According to a fifth aspect of the present invention, the pressure adjusting device is a pressure adjusting device for adjusting a fuel pressure to a fuel injection valve arranged facing an intake passage of an internal combustion engine, and the fluid is fuel. The fluid supply passage is a fuel supply passage extending from a fuel pump to the fuel injection valve, the outlet is connected to a fuel tank, and the control unit further includes a fuel injection passage that is injected from the fuel injection valve. A fuel supply control device for an internal combustion engine, comprising: a pressure adjusting device according to any one of claims 1 to 4, which controls rotation of the electric motor so that the fuel pressure becomes higher as the amount increases.

According to the fifth aspect of the invention, even when the engine speed is the same, when the fuel injection amount is large, such as when the engine is heavily loaded, the fuel pressure is set high. Fuel can be injected toward the intake flow with a large flow rate or a large flow rate, so that fuel adhesion to the intake passage wall is suppressed, and a mixture with an appropriate air-fuel ratio is formed and supplied to the combustion chamber. it can. Also, even when the engine speed is the same, when the fuel injection amount is small such as when the engine is under a low load, the fuel pressure is low, so that the fuel injected toward the intake flow at a low flow rate adheres to the intake passage wall surface. Is suppressed, and also in this case, an air-fuel mixture having an appropriate air-fuel ratio can be formed. Further, when the fuel injection amount is small, the fuel pressure becomes low and the fuel injection time can be prolonged, so that the accuracy of injection amount control when a small amount of fuel is injected can be improved. As a result, the exhaust emission and the engine operation performance can be improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a crankcase compression type 2 equipped with a fuel injection valve 10 to which fuel whose fuel pressure has been adjusted by the pressure adjusting device of the present invention is supplied.
1 is a schematic overall view of a cycle water-cooled internal combustion engine. Internal combustion engine 1
Are the crankcase 2, cylinder 3 and cylinder head 4.
Are assembled and integrated. A crankshaft 5 is rotatably supported by the crankcase 2, and reciprocating motion of a piston 6 slidably fitted in the cylinder 3 is converted into a rotational motion of the crankshaft 5 via a connecting rod 7.

Further, a crank chamber 8 in the crankcase 2 is connected to an air cleaner (not shown) through an intake passage 9, and the intake passage 9 has a fuel injection valve 10, A throttle valve 11 and a reed valve 12 are provided.

A fuel injection valve 10, which supplies fuel to air passing through an intake passage 9 to form an air-fuel mixture, has a fuel supply passage connected to a discharge port of a fuel pump 13 driven by a crankshaft 5. The supply passage 14 is connected, and the high-pressure fuel sucked from the fuel tank 15 by the fuel pump 13 is
The fuel is supplied to the fuel injection valve 10 through the fuel supply passage 14. Further, in the middle of the fuel return passage 16 branched from the fuel supply passage 14 and connected to the fuel tank 15, the fuel pressure Pf of the fuel supply passage 14 is adjusted to adjust the fuel pressure Pf to the fuel injection valve 10. A pressure adjusting device 20 for adjusting the pressure is provided.

EC which is a control means for controlling the fuel injection valve 10 and an electric motor, which will be described later, provided in the pressure adjusting device 20.
U17 includes the engine speed NE, the throttle valve opening TH, the fuel injection valve 10
Pressure Pf supplied to the engine, intake pressure upstream of the throttle valve 11
Pb, pressure Pc in the crank chamber 8, temperature T in the crank chamber 8
c, a detection signal from a group of sensors for detecting the operating state of the internal combustion engine 1 such as the cooling water temperature Tw, the atmospheric pressure Pa and the atmospheric temperature Ta, and a stroke sensor 58 for detecting a position St of the movable retainer 43b described later. From the fuel injection valve 10 based on these detection signals.
The fuel injection timing and injection time, and the fuel pressure Pf by the pressure adjusting device 20 are controlled. Therefore, the fuel injection valve 10, the pressure regulator 20, and the ECU 17 are components of the fuel supply device of the internal combustion engine 1.

As shown in FIGS. 2 to 4, the pressure adjusting device 20 includes a spring case 21 and a cover 23 connected to one end of the spring case 21 by four bolts 22.
And a valve case 27 connected to the other end of the spring case 21 by three bolts 26 arranged at equal intervals in the circumferential direction via a fixing ring 24 and a diaphragm 25.

The diaphragm 25, which is a displaceable partition that separates a fuel chamber 28, which is a fluid chamber formed by the valve case 27, and a spring chamber 29, which is formed by the spring case 21, has an outer peripheral edge adjacent to the diaphragm 25. At the intermediate position between the two bolts 26 in the circumferential direction, three bolts 30 arranged at equal intervals in the circumferential direction are sandwiched between the fixing ring 24 and the valve case 27. In the center of the diaphragm 25, a holder 33 for holding a disc-shaped valve body 32 pressed through a sphere 31 and a fixing plate 34 are fixed with the inner peripheral edge of the diaphragm 25 held therebetween. Have been.

The valve case 27 has an inlet 35 connected to the fuel return passage 16 on the fuel injection valve 10 side, and an outlet 36 connected to the fuel return passage 16 on the fuel tank 15 side via a joint 37. Is provided. The inflow port 35 to which the strainer 38 is attached communicates or is blocked in the fuel chamber 28 with the outflow port 36 opened and closed by the valve element 32.

One end of a cylindrical coil spring 39 which is housed in a compressed state in a spring chamber 29 and applies a spring force to the diaphragm 25 in the valve closing direction of the valve body 32 has a plate-like shape fixed to the diaphragm 25. The other end is held by a movable retainer 43b, which is a movable member that can be displaced in the direction of the axis L1 of the coil spring 39 by a ball screw 41, in contact with a fixed retainer 40 fitted to the inner periphery of the fixed plate 34. It is held in contact.

That is, the ball screw 41 includes a screw shaft 42 having a spiral groove formed on the outer periphery and a nut 43 having a spiral groove formed on the inner periphery through a number of steel balls guided by the two spiral grooves. It is configured to engage. Among these, the screw shaft 42 is disposed at the end of the spring case 21 on the cover 23 side, and a bearing 44 having a sealing function to keep the space between the screw shaft 42 and the spring case 21 airtight is disposed on the cover 23. Spring case 21 and cover 23
It is supported rotatably. The nut 43 has a stepped cylindrical shape including a small-diameter portion 43a and a movable retainer 43b which is integrally formed at one end of the small-diameter portion 43a and has a larger outer diameter than the small-diameter portion 43a. are doing. In addition, a part of the outer periphery of the small diameter portion 43a is the axis L2 of the ball screw 41.
Has been cut out to form a plane parallel to
A circulation path for circulating the steel ball is provided in the notch 43c.

Then, the fixed retainer 4 of the movable retainer 43b
The other end of the coil spring 39 is in contact with the surface facing the zero. Further, the small-diameter portion 43a of the nut 43, which is located closer to the fixed retainer 40 than the movable retainer 43b, is arranged so that the outer periphery thereof is located inside the coil spring 39 with a slight gap. Also, coil spring 39
Axis L1 of the ball screw 41 coincides with the axis L2 of the ball screw 41, and the pressing force exerted on the coil spring 39 by the movable retainer 43b is
Since they are substantially parallel to the axes L1 and L2, the support stiffness of the coil spring 39 in the direction of the axis L1 increases, and the linearity of the spring force change becomes stable.

A cylindrical engaging screw 46 extending in the radial direction is screwed and fixed to the outer periphery of the movable retainer 43b. The engagement screw 46 passes through an elliptical slit 47 (see FIG. 4) formed on the side wall of the spring case 21 so as to extend in a direction parallel to the axis L1 of the coil spring 39, and extends outside the spring case 21. It protrudes. When the engagement screw 46 engages with the slit, the movable retainer
43b is guided so as to be displaceable in the direction of the axis L1 of the coil spring 39.

On the other hand, a reversible electric motor 48 controlled by the ECU 17 to rotate the screw shaft 42 of the ball screw 41
The screw shaft in a direction substantially orthogonal to the direction of the axis L2 of the screw shaft.
The electric motor 48 and the cover of the spring case 21 are arranged on the side of the spring case 21 so that the rotation shaft 49 is arranged in parallel with the axis 42 and the axis of the rotation shaft 49 is substantially parallel to the axis L2 of the screw shaft 42. It is connected to the 23 end. The rotation of the electric motor 48 is provided in a closed space 50 formed between the spring case 21 and the cover 23, and is constituted by a series of gears arranged along the end face of the spring case 21. Screw shaft 42 via the reduction gear mechanism 51
Is transmitted to

That is, in the space 50, the electric motor
The pinion gear 52 fixed to the rotary shaft 49 of the 48 has a large size of an intermediate gear 53 press-fitted and fixed to an intermediate shaft 55 rotatably supported by the spring case 21 and the cover 23 via a pair of bearings 56 and 57, respectively. The small-diameter gear 53b of the intermediate gear 53 meshes with the output gear 54, which is press-fitted and fixed to the screw shaft 42 between the two bearings 44 and 45 and integrally rotates. Therefore, the rotation of the electric motor 48 is controlled by a series of these gears.
The speed is reduced to a step and transmitted to the screw shaft 42. The gears 52, 53, and 54 are formed to be as thin as possible in the axial direction. Further, the rotating shaft 49 and the intermediate shaft 55 of the electric motor 48 are arranged at positions shifted in the circumferential direction with respect to the axis L1 of the coil spring 39.

Further, on the side wall of the spring case 21,
A stroke sensor 58 as a position detecting means for detecting a position St of the movable retainer 43b in the direction of the axis L2 is connected by two bolts 60 via a spacer 59 so as to be airtight with the spring case 21. I have. The stroke sensor 58 includes a sensor arm 63 fixed by a nut 62 so as to rotate integrally with a rotation shaft 61 of the stroke sensor 58, as shown in FIGS.
Is formed in a forked shape, and the head 46 of the engagement screw 46 is formed.
A recess 63a with which the shaft portion closer to a is engaged is provided. Then, according to the position St of the movable retainer 43b in the direction of the axis L2,
The rotation shaft 61 integrated with the sensor arm 63 rotates, and the amount of rotation is detected by a position detection mechanism provided in the stroke sensor 58 for detecting an angle, for example, a potentiometer.

Further, the spring chamber 29 is provided with a diaphragm.
25, a bearing 44 and a spacer 59 are made airtight, and an intake pressure Pb on the upstream side of the throttle valve 11 is introduced into the spring chamber 29 through a pressure introduction pipe 64 provided in the spring case 21. When the intake pressure Pb acts on the diaphragm 25, the fuel pressure Pf is adjusted so as to reflect the intake pressure Pb acting on the injection port of the fuel injection valve 10.

Next, the pressure adjusting device thus configured
20 and the operation of the fuel supply control device will be described. When the internal combustion engine 1 is operated, the fuel pumped by the fuel pump 13 is supplied to the fuel injection valve 10 through the fuel supply passage 14, and from the fuel supply passage 14 through the fuel return passage 16 to the pressure adjusting device 20. Into the fuel chamber 28, and the coil spring 39
The outlet 36 according to the valve closing force of the valve body 32 due to the spring force of the valve body 32 and the valve opening force of the valve body 32 due to the fuel pressure Pf acting on the diaphragm 25.
Is opened and closed.

That is, when the fuel pressure Pf in the fuel supply passage 14 is higher than the fuel pressure set by the spring force of the coil spring 39, the fuel chamber 28 acting on the diaphragm 25
Due to the fuel pressure Pf, the diaphragm 25 is displaced toward the coil spring 39 against the spring force of the coil spring 39, the valve body 32 opens the outlet 36, and fuel flows from the outlet 36 through the fuel return passage 16 to the fuel. It is returned to the tank 15. When the fuel pressure in the fuel supply passage 14 decreases to the set fuel pressure Pf due to the outflow of the fuel from the outlet 36, the diaphragm 25 is displaced toward the fuel chamber 28 by the spring force of the coil spring 39. The valve 32 closes the outlet 36. In this manner, a fuel pressure Pf corresponding to the spring force of the coil spring 39 is obtained. Under the fuel pressure Pf, the fuel injection valve 10
The valve is opened by a command from 17 and the fuel of the calculated fuel injection amount is supplied to the intake passage 9.

The fuel pressure Pf is adjusted by controlling the forward or reverse rotation of the rotating shaft 49 of the electric motor 48 controlled by a command from the ECU 17 through the reduction gear mechanism 51.
The screw shaft 42 is rotated forward or backward, and the engaging screw 46 is guided along the slit 47.
The movable retainer 43b integral with the coil spring 39 is the axis L
The displacement is made in one direction, the coil spring 39 expands and contracts in the direction of the axis L1, and the spring force is adjusted.
Therefore, the movable retainer 43b, the ball screw 41, the electric motor 48 and the ECU 17 constitute an adjusting means for adjusting the spring force of the coil spring 39.

At this time, due to the rotation of the electric motor 48, the movable retainer 43b is shown by a solid line at a position set to the maximum fuel pressure, for example, about 1177 kPa (12 kgf / cm ² ) in FIGS. In the range of the position St ₁ and the position St ₂ indicated by the ^two- dotted line which is the position set at the lowest fuel pressure, for example, about 98.07 kPa (1 kgf / cm ² ),
Displace to any position. This allows the coil spring
By adjusting the spring force of 39 and therefore the valve opening load of the valve element 32 steplessly, the fuel pressure Pf of the fuel supply passage 14 is steplessly adjusted.

The ECU17, like the target fuel pressure Pf _t is obtained by the pressure adjusting device 20, determines the position of the movable retainer 43b by an electric motor 48. Below, target fuel pressure Pf _t
Will be described with reference to the flowchart of FIG. Here, during the intake stroke of the internal combustion engine 1, the fuel injection valve
In order to terminate the fuel injection from 10, the fuel pressure corresponding to the fuel injection amount controlled according to the engine operating state
Pf is adjusted.

First, in step S1, a basic fuel injection amount map in which the engine speed NE and the throttle valve opening TH which is the engine load are set as parameters is searched, and the detected engine speed NE and throttle valve opening are detected. Basic fuel injection amount Qf ₀ corresponding to degree TH is determined. Next, in step S2,
Fuel required for the fuel injection amount when the fuel injection is injected at injection angle Ai is the rotation angle of the crankshaft 5 to the end is started is equal to the basic fuel injection quantity Qf ₀ obtained in step S1 Find the pressure Pf. Therefore, according to equation (1), the reference fuel pressure is obtained at the engine speed NE at that time.
Pf _base , eg injection angle under set maximum fuel pressure
A reference fuel injection amount Qf _base when fuel is injected with Ai is obtained. Qf _base = Ai / (NE × Ki) (1) Here, the coefficient Ki is a numerical value corresponding to the ratio of the fuel injection time and the fuel injection amount at the reference fuel pressure Pf _base , that is, the reciprocal of the fuel flow rate. This is a preset coefficient representing a characteristic unique to the fuel injection valve 10. The injection angle Ai is the engine speed
It can be changed according to NE and engine load.

Next, using the relational expression between the fuel injection amount and the fuel pressure, the engine speed NE at that time is calculated according to equation (2).
In the target fuel pressure Pf _t is calculated required for injecting the basic fuel injection quantity Qf ₀ at injection angle Ai. _{Pf t = (Qf 0 / Qf} base) 2 × Pf base ... (2) Then, the target fuel pressure Pf _t map of a target position of the movable retainer 43b which is a parameter, the target fuel pressure obtained by the equation (2) target position of the movable retainer 43b corresponding to the pf _t is determined. As described above, the target fuel pressure Pf _t is set based on the basic fuel injection amount Qf ₀ set in accordance with the engine speed NE and the throttle valve opening TH, and the basic fuel injection amount Qf ₀
As when there are many, the target fuel pressure Pf _t is set high.

In step S3, the ECU 17 controls the rotation of the electric motor 48 so that the movable retainer 43b occupies the target position, and the rotation is transmitted to the screw shaft 42 of the ball screw 41 via the reduction gear mechanism 51. Then, the movable retainer 43b is displaced, and the spring force of the coil spring 39 is adjusted. At this time, the position St of the movable retainer 43b is detected by the stroke sensor 58, and the rotation of the electric motor 48 is feedback-controlled so that the movable retainer 43b occupies the target position. Position adjustment is performed.

Further, the ECU 17 determines the fuel injection time of the fuel injection valve 10 according to the procedure shown in the flowchart of FIG.
Determine Ti. First, in step S10, it is searched the basic fuel injection amount map, the basic fuel injection quantity Qf ₀ corresponding to the detected engine speed NE and the throttle valve opening TH is determined,
At step S11, the atmospheric pressure P detected by each sensor
a, the atmospheric temperature Ta, the intake pressure upstream of the throttle valve 11 Pb, the pressure Pc in the crank chamber 8, the temperature Tc in the crank chamber 8, and the like based on the coolant temperature Tw, the basic fuel injection amount Qf ₀ correction Thus, the fuel injection amount Qf is determined. In the following step S12,
Using the fuel pressure Pf detected by the sensor, equation (3)
Is used to determine the fuel injection time Ti. Ti = (Pf _base / Pf) ^1/2 × Ki × Qf (3) Then, in step S13, the fuel injection valve 10 is opened for the fuel injection time Ti in response to a command from the ECU 17, and fuel flows into the intake passage 9. It is injected. At this time, the fuel injection start timing is set so that the fuel injection ends during the intake stroke of suction into the crank chamber 8 through the reed valve 12.

The operation and effect of this embodiment will be described below. In order to adjust the spring force for adjusting the fuel pressure Pf, a movable retainer 43 which expands and contracts the coil spring 39 by being displaced by contacting the other end of the coil spring 39.
b is displaced by the ball screw 41 having a small frictional resistance. Therefore, the movable retainer 43b overcomes frictional resistance.
The output of the electric motor 48 for displacing the pressure may be small, the small electric motor 48 can be used,
20 becomes compact. Further, by using the ball screw 41, the position St of the movable retainer 43b can be set with high accuracy, and the movable retainer 43b can be quickly displaced, so that high-precision and quick pressure adjustment can be performed.

The small diameter portion 43a of the nut 43 of the ball screw 41
Since the spring guide is configured with a slight gap inside the coil spring 39, the coil spring 39 can be prevented from falling down and the linearity of the spring force change when the spring force is adjusted can be maintained. In addition, the pressure can be adjusted with high accuracy, and the movable retainer 43b is provided on the nut 43 disposed inside the coil spring 39, so that the dimension of the screw shaft 42 of the pressure adjusting device 20 in the direction of the axis L2 is reduced. Therefore, the pressure adjusting device 20 can be made compact.

An electric motor 48 is arranged in parallel with the screw shaft 42, and a reduction gear mechanism 51 for transmitting the rotation of the electric motor 48 to the screw shaft 42 is arranged along the end face of the spring case 21 forming the spring chamber 29. Because the pressure regulator 20
Of the screw shaft 42 in the direction of the axis L2 can be reduced, and the pressure regulator 20 can be made compact.

Further, since the series of gears 52, 53, 54 constituting the reduction gear mechanism 51 have a reduced thickness in the axial direction, the size of the screw shaft 42 of the pressure adjusting device 20 in the direction of the axis L2 is also reduced. Can be smaller. Further, since the rotating shaft 49 and the intermediate shaft 55 of the electric motor 48 are arranged at positions shifted in the circumferential direction with respect to the axis L1 of the coil spring 39, the radial dimension of the pressure adjusting device 20 is also reduced. be able to.
In addition, since the reduction gear mechanism 51 is disposed in the closed space 50 formed by the spring case 21 and the cover 23, dust and the like can be prevented from entering, and the durability of the pressure adjusting device 20 is improved.

Further, since the rotation of the electric motor 48 is transmitted to the screw shaft 42 via the reduction gear mechanism 51, a large torque is applied to the screw shaft 42, thereby easily and stably moving by overcoming the frictional resistance. Since the retainer 43b can be moved, accurate pressure adjustment can be performed.

The movable retainer is detected by the stroke sensor 58.
Position St of 43b, i.e. is detected degree of adjustment of the spring force of the coil spring 39, the movable retainer 43b is, rotation of the electric motor 48 so as to occupy the target position set corresponding to the target fuel pressure Pf _t feedback Therefore, the position of the movable retainer 43b is controlled with high precision, and the pressure can be adjusted with higher precision.

[0048] Then, the target position is set corresponding to the target fuel pressure Pf _t which is determined based on the basic fuel injection quantity Qf ₀ corresponding to the engine speed NE and the throttle valve opening TH,
The more basic fuel injection quantity Qf _0, the spring force of the coil spring 39 so that the fuel pressure Pf is high is adjusted. Therefore, even when the engine speed NE is the same, when the fuel injection amount is large, such as when the engine is under a high load, the fuel pressure Pf is set high. Since fuel is injected toward a large intake flow, fuel adhesion to the wall of the intake passage 9 is suppressed, and an air-fuel mixture with an appropriate air-fuel ratio can be formed and supplied to the combustion chamber. Also,
Even when the engine speed NE is the same, when the fuel injection amount is small such as when the engine is under a low load, the fuel injected toward the intake flow having a small flow rate is reduced because the fuel pressure Pf is low.
Adhesion to the wall surface is suppressed, and in this case also, an air-fuel mixture having an appropriate air-fuel ratio can be formed. Further, when the fuel injection amount is small, the fuel pressure Pf becomes low and the fuel injection time Ti can be lengthened, so that the accuracy of the injection amount control when a small amount of fuel is injected can be improved. As a result, the exhaust emission and the engine operation performance can be improved.

Hereinafter, an embodiment in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration. In the above embodiment, the internal combustion engine 1 has two cycles, but may have four cycles. Also,
Although the fuel injection valve 10 is arranged in the intake passage 9 upstream of the throttle valve 11, it may be arranged in the intake passage 9 downstream of the throttle valve 11.

In the above embodiment, the pressure adjusting device 20 adjusts the fuel pressure Pf to the fuel injection valve 10 of the internal combustion engine 1. However, the fluid pressure in the fluid supply passage through which fluid other than fuel is supplied is adjusted. It can also be applied to a pressure adjusting device for adjusting the pressure.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a schematic overall view of a two-cycle internal combustion engine to which a pressure adjusting device is applied.

FIG. 2 is a view of the fuel adjusting device as viewed in the direction of the arrow II in FIG. 3;

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

4 is a view taken in the direction of an arrow IV in FIG. 3 when a stroke sensor is removed.

FIG. 5 is a sectional view taken along line VV of FIG. 4 in a state where a stroke sensor is attached.

FIG. 6 is a flowchart showing a procedure for determining a target fuel pressure.

FIG. 7 is a flowchart showing a procedure for determining a fuel injection time.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Crank case, 3 ... Cylinder, 4
... Cylinder head, 5 ... Crank shaft, 6 ... Piston, 7
... connecting rod, 8 ... crank chamber, 9 ... intake passage, 10 ... fuel injection valve, 11 ... throttle valve, 12 ... reed valve, 13 ... fuel pump, 14 ... fuel supply passage, 15 ... fuel tank, 16 ... fuel return passage , 17… ECU, 20… Pressure adjusting device, 21… Spring case, 22… Bolt, 23… Cover, 24… Fixing ring, 25
... diaphragm, 26 ... bolt, 27 ... valve case, 28 ... fuel chamber, 29 ... spring chamber, 30 ... bolt, 31 ... sphere, 32 ... valve, 33 ... holder, 34 ... fixed plate, 35 ... inlet, 36 … Outlet, 37… Fitting, 38… Strainer, 39… Coil spring, 40… Fixed retainer, 41… Ball screw, 42… Screw shaft,
43… Nut, 43a… Small diameter part, 43b… Movable retainer, 44, 45
... bearing, 46 ... engaging screw, 47 ... slit, 48 ... electric motor, 49 ... rotary shaft, 50 ... space, 51 ... reduction gear mechanism, 52,5
3, 54 ... gear, 55 ... intermediate shaft, 56, 57 ... bearing, 58 ... stroke sensor, 59 ... spacer, 60 ... bolt, 61 ... rotating shaft,
62 ... nut, 63 ... sensor arm, 64 ... pressure introduction pipe,
L1, L2 ... axis lines.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 69/00 340 F02M 69/00 340S G05D 16/06 G05D 16/06 (72) Inventor Tsuyoshi Kano Saitama 3-15-1, Izumi, Asaka-shi F-term in Honda Racing Co., Ltd. (Reference) 3G066 AA01 AA08 AB02 AD10 BA02 BA12 BA19 BA23 BA51 BA67 CB07T CB07U CB15 CB16 CD25 CD26 CE13 CE21 CE34 CE40 DB08 DB09 DC03 DC04 DC09 DC13 DC17 DC18 DC19 3G301 HA01 HA03 JA03 JA21 KA08 KA09 LB06 NA03 NA06 NC02 ND02 PA07Z PA10Z PA11Z PB00Z PB08A PB08Z PE00Z PE01Z PE08Z 5H316 AA09 BB01 DD06 DD07 DD11 EE02 EE10 EE14 FF13 FF31 JJ37 GG04

Claims (5)

[Claims] 1. A displaceable partition for partitioning a fluid chamber and a spring chamber, an inlet communicating with an outlet provided in the fluid chamber and a fluid supply passage, and an outlet provided in the partition. A valve body that opens and closes, and a spring that is provided in the spring chamber and that applies a spring force to the partition in a valve closing direction of the valve body, wherein the spring force acts on the valve closing force of the valve body and acts on the partition. A pressure adjusting device that adjusts the pressure of the fluid in the fluid supply passage by opening and closing the outlet according to the valve opening force of the valve body due to the pressure of the fluid in the fluid chamber, wherein the spring force is adjusted. Adjusting means is provided, the adjusting means includes a movable member abutting on the spring, a ball screw for displacing the movable member, an electric motor for driving the ball screw to rotate, and a control for controlling the rotation of the electric motor. And means, Serial pressure regulating device characterized by spring force is adjusted by the movable member is displaced by the ball screw. 2. The ball screw according to claim 1, wherein the spring is a coil spring, and a screw shaft of the ball screw is rotationally driven by the electric motor, and a nut of the ball screw displaced in an axial direction of the coil spring is provided inside the coil spring. The pressure adjusting device according to claim 1, wherein the movable member is provided on the nut, and the movable member is provided on the nut. 3. The electric motor is disposed in parallel with the screw shaft, and rotation of the electric motor is transmitted via a gear mechanism disposed along an end face of a case forming the spring chamber. The pressure adjusting device according to claim 2, wherein the pressure is transmitted to the screw shaft. 4. A position detecting means for detecting a position of the movable member which is displaced, wherein the control means performs feedback control of the position of the movable member to a target position based on a detection signal of the position detecting means. The pressure adjusting device according to any one of claims 1 to 3, wherein the rotation of the electric motor is controlled. 5. The pressure adjusting device according to claim 1, wherein the pressure adjusting device is a pressure adjusting device that adjusts a fuel pressure to a fuel injection valve arranged facing an intake passage of the internal combustion engine, wherein the fluid is fuel, and the fluid supply passage is A fuel supply passage extending from a fuel pump to the fuel injection valve, wherein the outlet is in communication with a fuel tank, and the control means further increases the fuel injection amount as the fuel injection amount from the fuel injection valve increases 5. A fuel supply control device for an internal combustion engine, comprising: a pressure adjusting device according to claim 1, wherein the rotation of the electric motor is controlled so as to obtain a pressure.