JPH07310565A - Valve control device of engine - Google Patents

Abstract

PURPOSE:To provide a valve control device of an engine by which fuel consumption of the engine can be improved without adding and device of high price to it. CONSTITUTION:This is the valve control device of an engine provided with intake valves 11a-11d, 12a-12d on the intake side of respective cylinders and exhaust valves 13a-13d on the exhaust side. This device is provided with valve timing control means 23, 24 changing the opening/closing timing of the intake valves when torque output from the engine can be small, and a throttle valve full opening means which drives a throttle valve adjusting air--fuel mixture flowing in the cylinders to the nearly full opening position when torque output from the engine can be small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine valve control device, and more particularly to an engine valve control device capable of reducing pumping loss at low load and optimizing valve timing under wide operating conditions. The present invention relates to a valve controller.

[0002]

2. Description of the Related Art As a conventional engine, for example, 199
"MOT" issued by Sanei Shobo Co., Ltd. on January 1, 2014
Miller cycle engines are known, as disclosed on page 156 of "OR FAN".

The magnitude of the torque of the engine is determined by the amount of air-fuel mixture flowing into the cylinder, but in the engine driven by the Miller cycle as described above, the apparent intake volume is small, as is well known. For this reason, the Miller cycle engine disclosed in the same magazine has a structure in which a small intake volume is pushed and pushed by adding the Risholum compressor disclosed on page 158 of the same magazine. As a result, the displacement for generating the same torque can be reduced, the engine can be downsized, the fuel consumption can be improved, and a large torque can be obtained from the low rotation range, or the fuel consumption with respect to the extracted torque can be reduced. It can be improved.

However, since the above-mentioned Lisholm compressor has a complicated shape, it is difficult to manufacture it.
And it is expensive.

Further, since the Miller cycle engine has a structure in which the amount of air-fuel mixture flowing into the cylinder is adjusted by the throttle valve, a negative pressure is produced from the throttle valve to the inside of the cylinder during the intake process of the engine. It is estimated that this causes pumping loss and deteriorates fuel efficiency. For this reason, it is conceivable to use the hydraulically driven valve disclosed on page 19 of the symposium "New Generation Gasoline Engine", which was planned by the Gasoline Engine Division Committee on January 21, 1994, but with a complicated configuration and It is expensive.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a valve control device for an engine which can improve the fuel efficiency of the engine without adding an expensive device.

[0007]

In order to solve the above-mentioned technical problem, the technical means taken in the invention of claim 1 is a throttle valve which opens and closes according to the operation amount of the accelerator operating means of a driver, and In a valve control device for an engine, which has an intake-side intake valve that is provided for each cylinder and that opens and closes according to the rotation of the engine and an exhaust-side exhaust valve, when the torque output from the engine may be small, the intake valve is opened and closed. The valve opening / closing timing control means for advancing or delaying the timing and the throttle valve fully opening means for driving the throttle valve to the fully open position or a position close to the fully open position when the torque output from the engine may be small.

Since the time for sucking the air-fuel mixture at a high engine speed is short, it is preferable that the valve opening / closing timing control device delays the intake valve closing timing at a high engine speed.

In order to detect whether the torque output from the engine may be small without providing an expensive device, it is preferable that the torque output from the engine be small when the operation amount of the accelerator operating means is small. It is good that

[0010]

According to the present invention, when the torque output from the engine may be small, the throttle valve fully opening means drives the throttle valve to a position near full opening, and the valve opening / closing timing control device controls the opening / closing timing of the intake valve. The intake volume of the cylinder can be reduced by increasing or decreasing the speed of the cylinder or by increasing or decreasing the opening time as compared with the normal case. As a result, the engine reduces the intake volume when the required torque is small, and is driven by the Miller cycle.When the torque that requires a large torque is needed, the engine does not need to reduce the intake volume and the normal Otto cycle. Driven.

Further, in the invention of claim 2, the valve opening / closing timing control device drives the closing timing of the intake valve late at the time of high engine rotation, so that a sufficient amount of the air-fuel mixture is introduced into the cylinder. .

Further, in the third aspect of the present invention, the judgment as to whether or not the torque output from the engine may be small is made when the operation amount of the accelerator operation means is small (for example, one third or less of the maximum operation amount). Just decide when.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described with reference to the drawings.

In the figure, for example, in each cylinder of the engine 10 having four cylinders (# 1 to 4), intake valves 11a to 11d driven by a high lift cam 26 and intake valve 12a driven by a low lift cam 27 are provided.
.About.12d, exhaust valves 13a to 13d driven by the low lift cam 28, and exhaust valves 14a to 14d driven by the high lift cam 29. (FIG. 2 shows only the first cylinder # 1 extracted.) The cams 26 and 27 are integrally formed with the intake side camshaft 21, and the cams 28 and 29 are integrally formed with the exhaust side camshaft 22 for rotational driving. In addition, the intake side camshaft 21 is connected to the intake side valve opening / closing timing control device 23,
The exhaust side camshaft 22 is rotationally driven by a timing belt 25 that engages with a crank pulley (not shown) of the engine 10 via an exhaust side valve opening / closing timing control device 24. A well-known valve opening / closing timing control device (VVT) may be used for the intake side and exhaust side valve opening / closing timing control devices 23 and 24. In this embodiment, the intake valves and the exhaust valves 11a to 11d, 12a are used.
˜12d, 13a to 13d, 14a to 14d will be described as being capable of performing linear control in which the opening / closing timing can be freely set, but is not particularly limited to this.
There is no problem in using a structure that can be opened and closed at a plurality of predetermined times.

As shown in FIG. 3, each cylinder (# 1 to # 4) has a throttle valve 70 for adjusting the amount of air-fuel mixture via intake valves 11a to 11d and 12a to 12d.
Connected with. The throttle valve 70 has a central shaft 7
The center shaft 71 is connected via a wire 72 to an accelerator pedal 73 which is an accelerator operating means and an electric motor 74 which constitutes a throttle valve fully opening means so as to be rotationally driven. It has become. (In FIG. 3, 17 is a cooling water channel, 18 is a spark plug, 19 is a distributor, and 20 is a fuel injection device.) The accelerator operating means adjusts the opening degree of the throttle valve 70 according to the intention of the driver. However, the present invention is not limited to this, and may be an accelerator switch used in a constant speed traveling device, an accelerator grip of a motorcycle, or the like.

Each valve 11a-11d, 12a-12
A variable lifter 30 as shown in FIG. 4 is provided at each of d, 13a to 13d and 14a to 14d. However, as will be described later, in the present embodiment, the lift amounts of the intake valves and the exhaust valves 12b, 13b, 12c, 13c driven by the low lift cams of the second and third cylinders (# 2, # 3) are variable. Variable lifter 3
0 may not be provided.

As described above, any number of variable lifters 30 may be arranged in any valve, and may be appropriately selected depending on the design.

Referring to FIG. 4, the variable lifter 30 arranged in the intake valve 11a will be described. (A variable lifter applied to other valves has the same structure.) A shim 32 is fixed to the selection of the stem 31 of the intake valve 11a, and a retainer 34 is fixed below the shim 32 via a cotter 33. There is. A valve spring 35 is stretched between the retainer 34 and the cylinder head 45 of the engine 10 to constantly urge the intake valve 11a toward a valve seat (not shown). That is, the intake valve 11a is closed by the valve spring 35.

A support member 41 and a cylinder member 42 are housed inside a body 40 of the main body of the variable lifter 30, and hydraulic passages 43 and 44 are formed in the body 40 and the holding member 41. The body 40 slides vertically through the hole 46 in the cylinder head 45, and the hydraulic passage 43 of the body 40 communicates with the hydraulic supply passage 47 of the cylinder head 45.

A cylinder 48 is formed in the cylinder member 42 in a direction orthogonal to the stem 31, and the inside of the cylinder 48 is formed by
The third pins 49, 50, 51 slide. In the cylinder 48, a hydraulic chamber 52 is formed on the left side of the first pin 49 in the drawing, and the hydraulic passage 44 of the support member 41 is opened. On the other hand, a spring seat 53 is provided on the right side of the third pin 51 in the figure.
A return spring 54 is stretched between and. A through hole 60 is formed coaxially with the stem 31 in the substantially center of the cylinder member 42, and a mover 57 is disposed in the through hole 60 so as to be slidable in the vertical direction in the figure. Mover 57
The shim 32 abuts on the lower surface thereof, the retainer 58 abuts on the upper surface thereof, and a spring 59 is stretched between the retainer 58 and the upper bottom surface of the body 40. or,
The mover 57 has a horizontal through hole of the same diameter as the cylinder 48,
The first to third pins 49, 50 and 51 are slidable.

A spring seat 55 is arranged on the lower surface of the support member 41 in the figure, and a support spring 56 is stretched between the support member 41 and the cylinder head 45. The support spring 56 serves to float-support the variable lifter 30 in the hole 46 in the cylinder head 45. 26 indicates a high lift cam. FIG. 6 shows a hydraulic pressure supply path to the variable lifter 30 in the first cylinder (# 1). In FIG.
From the main gallery 15 of the engine 10 to the central hydraulic passage 1
6 is substantially the center of the cylinder head 45, and each cam lifter 3
Via hydraulic passage 47. In this way, by making the central hydraulic passage 16 substantially at the center of the cylinder head 45,
Two pressures can be evenly supplied to the intake side and the exhaust side without any time difference.

The operation of the valve device of the engine 10 will be described with reference to FIG.

First, the "A mode" is selected when the engine is started (at a low temperature), and since the viscosity of the engine oil is high and the driving force of an oil pump (not shown) and the friction loss in the engine 10 are large, it is low. Only the intake valves 12a to 12d and the exhaust valves 13a to 13d driven by the lift cams 27 and 28 operate. That is, according to the cam lift curve of the low lift cam 28 on the exhaust side as shown by the solid line 80 in FIG.
13d is activated and the solid line 71 continues with zero overlap.
The intake valves 12a to 12d operate according to the cam lift curve of the low lift cam 27 on the intake side as shown by. Further, the intake side and exhaust side valve opening / closing timing control device 2
3, 24 and the electric motor 74 do not operate and the engine 10
Is driven by the Otto cycle.

By the way, the operation stop of each valve on the high lift cams 26, 29 side is achieved by the operation of the variable lifter 30 engaged with each valve as shown in FIG. That is, the hydraulic pressure supply from the main gallery 15 to the hydraulic chamber 52 is stopped, the pressure in the hydraulic chamber 52 is reduced, and the action of the return spring 54 causes the first to third pins 49, 50,
51 is urged to the left in the figure. This bias acts as a stopper for the first pin 49, and the left end surface in the drawing is the cylinder 4
8 is performed until it contacts the bottom surface on the left side in the drawing. Then, the stem 31, the second pin 50, and the mover 57 are aligned on a straight line. The movement of each of the pins 49 to 51 is performed by the high lift cam 26.
Is completed when is in the idle section. When the high lift cam 26 approaches the lift portion, the spring constant of the support spring 56 is set smaller than the spring constant of the valve spring 35, and the stem 31, the second pin 50 and the mover 57 are aligned. Since they are arranged side by side, the lift portion of the high lift cam 26 pushes down only the main body of the variable lifter 30 without pushing down the stem 31 (that is, without opening the valve). At this time, the spring 59 is compressed, and the stem 31, the mover 57, and the second pin 50 are relatively moved upward in the drawing through the through hole 60 while being guided by the first and third pins 49 and 51. Moving. (Here, the intake valve 11a driven by the high lift cam 26 of the first cylinder (# 1) was representatively described, but the same applies to the other valve.) Next, the "B mode" is when the engine is idling. (At high temperature), because the driving force of the oil pump and the friction loss in the engine 10 are small, the operation of all valves of the first and fourth cylinders (# 1, # 4) is stopped, Second,
Only the intake valves 12b and 12c and the exhaust valves 13b and 13c driven by the low lift cams 27 and 28 of the third cylinder (# 2, # 3) are operated. That is, the exhaust valves 13b and 13c operate according to the cam lift curve of the exhaust side low lift cam 28 shown by the solid line 82 in FIG. 9, and the intake side low lift cam 27 shown by the solid line 83 with a predetermined overlap amount.
The intake valves 12b and 12c operate according to the cam curve of the above. In the "B mode", the electric motor 74 is driven to drive the throttle valve 70 to a position close to full opening, and only the intake valve opening / closing timing control device 23 is linearly controlled to open and close the intake valves 12b and 12c. By advancing the engine 10, the engine 10 is driven in the early-closing Miller cycle. The intake valve 12
The intake volume may be reduced by advancing only the closing timing of b and 12c.

Next, "C mode" is selected when the engine is in the low / medium speed range and the required torque is small, and like the "B mode", the first, second and third cylinders ( #
Only the intake valves 12b, 12c and the exhaust valves 13b, 13c of 2, # 3) are operated, while the intake side and exhaust side valve opening / closing timing control devices 23, 24 are linearly controlled to arbitrarily set the overlap amount and the intake capacity. Controlled. That is, the intake valves and the exhaust valves 12b, 12c, 13b, 13c operate according to the cam curves of the intake side and exhaust side low lift cams 27, 28 as shown by the solid lines 84, 85 in FIG. At this time, the determination as to whether the torque output from the engine 10 is small or large may be made by corresponding to the operation amount of the accelerator pedal 73, for example, ON / OFF at a position that is one third of the maximum operation amount of the accelerator pedal 73. If such a switch is provided, the determination may be made at the timing at which the switch is turned on and off. In the "C mode", the intake valves 12b and 12c and the exhaust valve 1
Since the intake volume of the cylinder can be changed by arbitrarily setting the opening and closing timings of 3b and 13c, the torque of the engine 10 is changed by changing the intake volume based on the operation amount of the accelerator pedal 73. Is driven by an early closing Miller cycle.

Here, the exhaust valves 14b, 14c driven by the high lift cams 29 of the second and third cylinders (# 2, # 3) may also be operated (broken line 86 in FIG. 10).
In accordance with the cam lift curve of the high lift cam 28 on the exhaust side as shown by (4), the cam lift curve shown by the broken line 86 may be arbitrarily shifted by operating the exhaust side valve opening / closing timing control device 24.

Next, the "D mode" is selected when the engine is in the low / medium speed range and the required torque is large, and the opening / closing control of each valve is the same as the "A mode".
The only difference is that the exhaust side valve opening / closing timing control device 24 is operated. Low lift cams 26, 28 on the intake side and the exhaust side
The cam lift curves of the above are shown by the solid lines 87 and 88 in FIG.

In the "D mode", depending on various conditions of the engine 10, all valves may be operated as in the "F mode" to output a required torque. In this case, intake side and exhaust side high lift cams 27, 29
The cam lift curve of is shown by broken lines 89 and 90 in FIG. In "D mode", the solid line 88 and / or
The cam lift curve shown by the broken line 90 may be linearly shifted by the exhaust side valve opening / closing timing control device 24 to change the overlap amount. Further, the engine 10 is driven in the Otto cycle.

Next, the "E mode" is selected when the engine is in the high speed rotation range and the required torque is small, and the first and fourth cylinders (# 1, # 4) are selected from the viewpoint of low engine load. ) While stopping the operation of all valves,
From the standpoint of increasing the intake volume, only the intake valves 11b and 11c and the exhaust valves 14b and 14c driven by the high lift cams 26 and 29 of the second and third cylinders (# 2 and # 3) are operated. That is, FIG.
2, the exhaust valves 14b, 14c operate according to the cam lift curve of the exhaust side high lift cam 29 shown by the solid line 92, and the intake valves 11b, 11c follow the cam lift curve of the intake side high lift cam 26 shown by the solid line 91 with an overlap amount of 0. Works. "E mode"
In the same manner as in the "B mode" and the "C mode", the intake side and exhaust side valve opening / closing timing control devices 23 and 24 and the electric motor 74 are driven, and the intake valve and the exhaust valve are based on the operation amount of the accelerator pedal 73. 11
By setting the opening and closing timings of b, 11c, 14b, and 14c to be late (for example, 10% of the valve opening time) and changing the intake volume, the engine 10 is driven in the late-closing Miller cycle. Further, in the "E mode", the air-fuel mixture is prevented from running short because it is driven in the late-closing mirror cycle.

Here, in order to secure the amount of air-fuel mixture required for high rotation, depending on various engine conditions, the second and third air-fuel ratios are secured.
The intake valves 12b, 12c and the exhaust valves 13b, 13c driven by the low lift cams 27, 28 of the cylinders (# 2, # 3) may also be operated.

Finally, the "F mode" is selected when the engine is in the high speed rotation range and the required torque is large, and in order to output the required torque, the required intake air amount is large. All valves are activated. The cam lift curves shown by the solid lines 93 to 94 in FIG. 13 are obtained, and the engine 10 is driven in the Otto cycle. Further, the exhaust side valve opening / closing timing control device 24 operates to control the overlap amount linearly.

In the present embodiment, when the torque output from the engine may be small, the engine is driven in the Miller cycle and the electric motor 74 is operated to put the throttle valve 70 in the vicinity of the fully open position. Loss can be reduced, fuel efficiency can be improved, and when a large torque is required, it can be driven in the Otto cycle to obtain the necessary and sufficient torque. In this way, it is possible to improve the fuel efficiency by simply providing the inexpensive electric motor 74.

Further, in this embodiment, the throttle valve fully opening means is constituted by the electric motor 74, but the invention is not particularly limited to this, and there is no problem even if an actuator or the like driven by electromagnetic force is used. Absent.

Further, in this embodiment, the intake volume of the cylinder is changed by controlling the opening / closing timing of the intake valves 11a to 11d and 12a to 12d.
The torque of the intake valve 11a is changed.
The intake volume may be changed by changing the lift amounts of ˜11d, 12a to 12d and the working angles of the high lift cams and the low lift cams 26, 27, 28, 29.

Further, in the present embodiment, each cylinder is provided with four valves, which are further provided with the high lift cam 2.
6, 29 and the low lift cams 27, 28 are used for driving, but the structure is not limited to this and may be appropriately selected according to the design.

Further, in the present embodiment, it is not necessary to use an expensive sensor or the like because the determination as to whether the torque output from the engine 10 may be small is detected by the operation amount of the accelerator pedal 73.

[0037]

According to the first aspect of the present invention, when the torque output from the engine may be small, the engine is driven in the Miller cycle so that the fuel consumption is improved, and when a large torque is required, the engine is driven in the Otto cycle. Therefore, the necessary and sufficient torque can be obtained. In this way, it is possible to improve fuel efficiency without adding an expensive device. Further, when the load is low, the throttle valve is in the vicinity of the fully opened position, so that pumping loss of the engine is reduced and fuel consumption is improved.

In the second aspect of the present invention, the valve opening / closing timing control device drives the intake valve closing timing late by a predetermined amount when the engine is rotating at high speed, so that a sufficient amount of the air-fuel mixture is introduced into the cylinder. Therefore, the required torque can be obtained.

In the third aspect of the invention, since it is determined whether or not the torque output from the engine may be small by the operation amount of the accelerator operating means, it is not necessary to use an expensive sensor or the like.

[Brief description of drawings]

FIG. 1 shows a valve arrangement of a valve control device for an engine according to the present invention.

FIG. 2 shows a detailed view of the first cylinder in FIG.

FIG. 3 shows a cross-sectional view of an engine according to the present invention.

FIG. 4 is a sectional view of a variable lifter.

FIG. 5 shows a sectional view of the variable lifter during operation.

FIG. 6 shows a hydraulic circuit diagram of a first cylinder.

FIG. 7 shows an operating mode diagram.

FIG. 8 shows a cam lift curve diagram in A mode.

FIG. 9 shows a cam lift curve diagram in B mode.

FIG. 10 shows a cam lift curve diagram in C mode.

FIG. 11 shows a cam lift curve diagram in D mode.

FIG. 12 shows a cam lift curve diagram in E mode.

FIG. 13 shows a cam lift curve diagram in F mode.

[Explanation of symbols]

10 ... Engine 11a-11d, 12a-12d ... Intake valve 13a-13d, 14a-14d ... Exhaust valve 23 ... Intake side valve opening / closing timing control device 24 ... Exhaust side valve opening / closing timing control Device 70 ... Throttle valve 74 ... Electric motor (Throttle valve fully opening means)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area F02D 43/00 301 Z K

Claims (3)

[Claims] 1. A throttle valve that opens and closes in accordance with an operation amount of a driver's accelerator operating means, and an intake valve on an intake side and an exhaust valve on an exhaust side that are provided for each cylinder and open and close according to rotation of an engine. In an engine valve control device having the valve opening / closing timing control means for advancing or delaying the opening / closing timing of the intake valve when the torque output from the engine may be small, and the torque output from the engine may be small. A valve control device for an engine, comprising: a throttle valve fully opening means for driving the throttle valve to a fully opened position or a position near the fully opened position. 2. The valve control device for an engine according to claim 1, wherein the valve opening / closing timing control means delays the closing timing of the intake valve when the engine is rotating at high speed. 3. The valve control device for an engine according to claim 1, wherein when the torque output from the engine may be small, the operation amount of the accelerator operating means is small.