JPS6263130A - Suction device for engine - Google Patents

Abstract

PURPOSE:To make accurate detection performable, by performing the detection of engine load at the time of low load with the valve open timing of a rotary valve in the bypass passage installed so as to bypass a shutter valve in a suction passage and an engine speed. CONSTITUTION:This suction device is made up of installing a shutter valve each to a suction passage 10a to be connected to a suction port 3 of each cylinder, and a rotary valve 18 in the bypass passage 15a installed so as to bypass the shutter valve 11a side by side. At a low load range, the shutter valve 11a is closed, while the rotary valve 18 is closed in the point midway in a suction stroke, and it controls valve open timing of the said valve 18 so as to be delayed according to an increase in the opening of an accelerator pedal. At this juncture, when engine load is detected at the time of low load, each detection signal of the valve open timing of the rotary valve 18 and an engine speed is inputted into a control unit (unillustrated herein), and the engine load is detected according to these detection signal.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine intake system, and particularly relates to an improvement in the intake system for improving combustibility and reducing pumping loss in a low load range.

(Prior Art) Conventionally, as an intake system for this type of engine, a shutter valve that opens when the accelerator pedal opening is equal to or greater than a predetermined opening is provided in the intake passage, as disclosed in Japanese Patent Laid-Open No. 58-23245, for example. At the same time, a rotary valve that rotates at a rotation speed ratio of 1/2 to the rotation of the camshaft is arranged in a small diameter bypass passage that bypasses the shutter valve. In the load range, the intake passage is closed by the closing operation of the shutter valve and intake air is supplied only from the bypass passage, thereby increasing the flow velocity of the intake air and generating an intake swirl to improve combustion performance and improve combustion performance. It is known that the valve is closed in the middle of the intake stroke to reduce pumping loss and thereby improve fuel efficiency. In the above system, when the accelerator pedal is pressed to a predetermined opening degree or more from a low load range and the load is high, the shutter valve opens and the intake passage opens, allowing intake air to flow from this intake passage as well as the bypass passage. is supplied to improve the output.

(Problems to be Solved by the Invention) By the way, in an engine intake system equipped with a shutter valve and a rotary valve as described above, when opening the shutter valve at a predetermined accelerator pedal opening, when the load is low, the low-return valve may open during its intake stroke. Bumping loss is reduced by the so-called mirror cycle by closing the valve, but when the accelerator pedal opening reaches a predetermined opening and the shutter valve opens, the intake air is supplied from the intake passage. The intake end timing suddenly changes from the middle of the intake stroke to the end of the normal intake stroke, causing a sudden switch from the Miller cycle to the normal cycle (Otto cycle), causing torque shock.
The disadvantage is that a smooth increase in engine output cannot be achieved.

On the other hand, in an engine having a rotary valve in the intake system as described above, when controlling, for example, the ignition time, air-fuel ratio, or the amount of exhaust gas recirculated to the engine for exhaust gas purification according to the engine load, only the bypass passage can be used. At low load, where intake air is supplied from the engine, the intake negative pressure is small, and the intake negative pressure fluctuates little by little due to the repeated opening and closing of the rotary valve, making it difficult to accurately detect the intake negative pressure. For this reason, when the engine load is normally detected using the intake negative pressure and the engine speed, the control accuracy of the ignition timing and the like decreases in the low load range, which is not preferable.

Therefore, in order to reduce the torque shock when switching from the former Miller cycle to the Otto cycle, the inventors of the present invention decided to increase the accelerator pedal opening by adjusting the closing timing of the rotary valve at low load when the shutter valve is closed in advance. By delaying the timing according to the timing and bringing it closer to the end of the intake stroke, it is possible to smoothly switch from the Miller cycle to the Otsuto cycle, effectively reducing torque shock, and thus obtaining a smooth increase in engine output. I devised it.

In that case, the amount of intake air at low load is proportional to the open period of the rotary valve, which overlaps with the open period of the intake valve. Therefore, an object of the present invention is to detect the engine load at low load. Instead of intake negative pressure, which is difficult to accurately detect, the valve opening timing (timing for keeping the valve open) relative to the crank angle of the rotary valve is used, and the engine load is detected based on the rotary valve opening timing and engine speed. By doing so, the engine load can be accurately detected regardless of the intake negative pressure, and the ignition timing and the like can be accurately controlled in accordance with the engine load.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention includes disposing a shutter valve in the intake passage for opening and closing the intake passage, and providing a bypass passage for bypassing the shutter valve. A rotary valve is arranged to open and close the bypass passage,
The present invention assumes an engine intake system in which the shutter valve is closed in a low load range, the rotary valve is closed in the middle of the intake stroke, and the closing timing of the rotary valve is delayed in accordance with an increase in the accelerator pedal opening. .

Further, a valve opening timing detection means for detecting the opening timing of the rotary valve and a rotation speed detection means for detecting the rotation speed of the engine are provided, and the engine load is detected by the valve opening period detection means and the rotation speed detection means. The load detection means is configured to detect the load.

(Function) With the above configuration, in the present invention, when the load is low and intake air is supplied only from the bypass passage by the opening operation of the shutter valve, the closing timing of the rotary valve is controlled to be delayed in accordance with the increase in the opening degree of the accelerator pedal. Since the end of the intake stroke is approached, the switching from the Miller cycle to the Otto cycle is performed smoothly, reducing torque shock.

Since the valve opening period of the rotary valve increases and the amount of intake air increases due to the delay control of the valve opening timing of the rotary valve, the valve opening timing of the rotary valve corresponding to this increase in the intake air amount increases. Since it is used to detect the engine load along with the rotation speed, the accuracy of detecting the engine load is effectively increased without being affected by the magnitude of the intake negative pressure or its small fluctuations due to the opening/closing operation of the rotary valve. be.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 and FIG. 2 show an embodiment applied to an intake system for a four-cylinder, four-cycle engine. In the same figure, 1 is the first
~An engine having fourth cylinders 18 to 1d, 2 is a combustion chamber formed in each cylinder 1a to 1d of the engine 1, and an intake boat 3 and an exhaust boat 4 are opened in the eight combustion chambers 2. An intake valve 5 is disposed at the opening of the intake boat 3 to the combustion chamber 2, and an exhaust valve 6 is disposed at the opening of the exhaust boat 4 to the combustion chamber 2.

Further, reference numerals 108 to 10d are intake passages whose one end communicates with the atmosphere and whose other end opens into each combustion chamber 2 via the intake boat 3 to supply intake air to each cylinder 1a to 1d of the engine 1. A shutter valve 11 for opening and closing each intake passage 10a-10d is provided near the intake boat 3 of each intake passage 10a-10d.
a to 11d are arranged, and each shutter valve 11
a to 11d are serially and operatively connected to a valve shaft 12 arranged in the direction of the cylinder row. In addition, each intake passage 1Qa~
Immediately downstream of the shutter valves 11a to Tld of 10d, fuel injection valves 13 for injecting and supplying fuel are respectively disposed.

Each of the above-mentioned intake passages 10a to 10d includes an intake passage 10
The first to fourth bypass passages 15a to 15a communicate the upstream side of the shutter valves 11a to 11d of 8 to 10d and the intake boat 3 by bypassing the shutter valves 11a to 11d.
15d is provided. Each of the bypass passages 15a to 1
5d has a passage cross-sectional area smaller than that of the intake passages 10a to 10d, and its downstream end opening opens toward the circumferential direction of the combustion chamber 2, directing intake air to the bypass passage 15.
By inhaling into the combustion chamber 2 through a to 15d,
An intake swirl is generated in the combustion chamber 2 along the circumferential direction.

In the middle of each of the bypass passages 15a to 15d, a single rotary valve 18 rotatably disposed within a cylindrical member 16 disposed in the cylinder row direction via a sleeve 17 is interposed in common. . The rotary valve 18
is constructed of a hollow body, and its end on the first cylinder 1a side is closed by inserting a rotating shaft 31a of a sun gear 31 of a planetary gear mechanism 23, which will be described later.
The end on the d side is closed with a closing member 19, and a bag-shaped intake air supply passage 20 is formed inside, and the outer circumference facing each bypass passage 15a to 15d has a corresponding cylinder 1a to 15d. In the angular range corresponding to the intake stroke 1d, a portion corresponding to the opening period of the intake valve 5 is cut out in the circumferential direction to form an opening 18a, and as the rotary valve 18 rotates once, each opening on the outer periphery of the opening 18a is formed. When the rotary valve 18a communicates with the bypass passages 158 to 15d on the downstream side of the rotary valve 18, intake air can be supplied to the combustion chamber 2 through the bypass passages 15a to 15d depending on the open/closed state of the intake valve 5.

Further, the rotary valve 18 is connected to the end of the rotary valve 18 on the first cylinder 1a side via a planetary gear mechanism 23.
A large diameter pulley 24 for rotational driving is connected, and the pulley 2
4, a belt 27 is wound around a small diameter pulley 26 provided at the end of a camshaft 25 arranged above the combustion chamber 2 in the direction of the cylinder row, and the rotation of the camshaft 25 causes a rotary valve. 18 to rotate. The planetary gear mechanism 23 includes a ring gear 28 coaxially connected to the large diameter pulley 24, and three planetary gears 30 meshing with the ring gear 28 and interconnected by a carrier 29.
The gear ratio of the planetary gear mechanism 23 is set in advance so that the ratio of the rotational speed of the rotary valve 18 to the camshaft 25 is "1". ing. In addition, the rotary valve 18
When the accelerator pedal is not depressed, when the planetary gears 30 of the planetary gear mechanism 23 are at the initial positions shown in the figure, each opening 18a is opened to each bypass! ! 15a to 15d are each positioned in advance to close at a predetermined time during the intake stroke. Furthermore, the carrier 2 of the planetary gear mechanism 23
9 is connected to an accelerator pedal (not shown) via a wire member 32, and when the accelerator pedal is depressed, the carrier 29 rotates clockwise in FIG. By shifting the position of each opening 18a of the rotary valve 18, the position of each opening 18a of the rotary valve 18 is gradually rotated clockwise in FIG. is gradually delayed according to the predetermined accelerator pedal opening degree O.
At A, the valve closing timing is made to coincide with the end of the intake stroke, so that the valve opening period of the rotary valve 18 almost overlaps with the valve opening period of the intake valve 5.

In addition, the upper one of the three planetary gears 30 of the planetary gear mechanism 23 has shutter valves 11a to 11.
d, a first link 36 extending in the direction of the valve shaft 12, and a longitudinal notch hole 37 formed at the end of the first link 36.
The ends of the valve shafts 12 of the shutter valves 118 to 11d are connected via a second link 39 having an engagement pin 38 that engages with the notch hole 37 of the first link 36.
The length of is set to a length corresponding to the time when the accelerator pedal opening reaches the predetermined accelerator pedal opening OA from the "011 value. Therefore, as shown in FIG. 3, when the accelerator pedal is depressed, At the initial stage, the first link 36 moves to the right in FIG. 2, but the engagement pin 38 of the second link 39 moves within the notch hole 37 of the first link 36, and the shutter valves 11a to 11d close. While maintaining the state.

Constant accelerator pedal open! When the LOA is reached, the engagement pin 38 of the second link 39 engages with the first link 36, and the valve shafts 12 of the shutter valves 11a to 11d rotate clockwise in FIG. is gradually increased in accordance with an increase in the degree of opening of the accelerator pedal.

Further, an opening sensor 45 is disposed near the planetary gear mechanism 23 as a valve opening timing detection means for detecting the opening timing of the rotary valve 18 which detects the amount of rotational displacement of the carrier 29 of the planetary gear 30. At the same time, a rotation speed sensor 46 for detecting the engine rotation speed is provided,
The opening sensor 45 and the rotation speed sensor 46 constitute a load detection means 47 that detects the engine load.

The rotary valve opening OR signal from the opening sensor 45 and the engine rotational speed Ne signal (output) from the rotational speed sensor 46 are input to an ignition timing control device 48 including a CPtJ and the like.

As shown in FIG. 4, the ignition timing control device 148 has the engine rotation speed NO on the horizontal axis and the rotary valve opening OR in place of the intake negative pressure on the vertical axis, as shown in FIG.
A number of ignition timings are inputted and stored so as to obtain a good combustion state in the entire engine load range determined by dividing lil OR/N e by +3. And the ignition timing control device! Reference numeral 48 indicates the current engine current from the ignition timing map shown in FIG. It reads the ignition timing corresponding to the load and controls the ignition of the ignition plug (not shown) so that ignition occurs at this ignition timing.

In FIG. 2, reference numeral 41 indicates an assist air passage for supplying assist air to the vicinity of the injection port 13a of each fuel injection valve 13, and one end of the assist air passage 41 is connected to the intake passage 1.
The other end is connected to an air cleaner (not shown) disposed upstream of the collecting section 0a to 10d, and the other end is formed in a large number of small holes 42a...
The fuel injection valve 13 is connected to the vicinity of the injection port 13a of the fuel injection valve 13 through the fuel injection valve 13, and when the load is low, in which intake air is supplied only from the bypass passages 15a to 15d, that is, when there is no intake air flow around the fuel injection valve 13, the fuel injection valve The fuel from the assist air passage 41 is atomized by the assist air from the assist air passage 41, so that the air-fuel mixture within the combustion chamber 2 can be burnt efficiently.

Therefore, in the above embodiment, the shutter valve 1
During low load when 1a to 11d are in the closed state, intake air is supplied to the combustion chamber 2 only from the bypass passages 15a to 15d, so that the intake air flow rate increases and a swirl is generated in the intake air to improve combustibility. . In addition, since the intake end timing is set in the middle of the intake stroke by the rotary valve 18, the pumping loss is reduced, and as a result,
Improved fuel efficiency is achieved. Moreover, in this case, the effective compression ratio in the next compression stroke decreases due to the end of the intake in the middle of the intake stroke, resulting in combustion of the air-fuel mixture 21! Although the sentence is in a situation where it decreases, a swirl is generated in the intake, so
Good flammability is ensured.

Furthermore, when the accelerator pedal is depressed, the closing timing of the rotary pulse 718 is delayed and controlled in accordance with the increase in the accelerator pedal opening, and the amount of intake air is gradually increased.Afterwards, when the accelerator pedal opening is 0^, the rotary pulse When the closing timing of the valve 18 coincides with the end of the intake stroke and the opening period of the rotary valve 18 almost overlaps with the opening period of the intake valve 5, from this point on, the opening of the shutter valves 11a to 11d will change depending on the opening of the accelerator pedal. Since the intake air amount is controlled to increase gradually as the engine temperature increases, the amount of intake air is further increased gradually, and the engine output is improved.

At that time, the start of opening of the shutter valves 11a to 11d is as follows.
Rotary valve 1 at the position of the predetermined accelerator pedal opening OA
Since the valve closing timing in step 8 coincides with the end of the intake stroke, the switching from the so-called Miller cycle to the Otto cycle is carried out smoothly, preventing torque shock, and thus smoothly increasing engine output. can be ensured.

In that case, at low load times when intake air is supplied only from the bypass passage due to the closing operation of the shutter valves 11a to 11d, the intake negative pressure is small and fluctuates little by little due to the opening and closing operations of the rotary valve 18; The engine load at this time is detected based on the valve opening timing of the rotary valve 18 corresponding to the intake air amount, that is, the rotary valve opening *OR from the WJ degree sensor 45 and the engine rotation speed Ne, regardless of the intake negative pressure. As a result, the detection of the engine load becomes accurate, and as a result, the ignition timing IIJIll is performed as expected, and its control efficiency is improved.

Furthermore, the rotary valve 18 is 1:1 with respect to the camshaft 25.
Since it rotates at a rate of 1/1, the rotation rate is 1/1 with respect to the camshaft 25 as in the conventional case.
Compared to a rotary valve that rotates at a rotational speed ratio of 2.2, the effective opening area of the bypass passages 15a to 15d increases during the period when the rotary valve 18 is open, and the amount of intake air can be increased. Moreover, as the rotary valve 18 rotates at a ratio of 1:1 with respect to the camshaft 25, the positions of the openings 18a of the rotary valve 18 are different from that of a predetermined cylinder (for example, the first cylinder 1a) and a cylinder two strokes later than this (the fourth cylinder I). !1s1d), so that the opening 18a corresponding to a predetermined cylinder (for example, the first cylinder 1'a') is connected to the first bypass downstream of the rotary valve 18. When communicating with the passage 15a, the opening 18a corresponding to the fourth cylinder 1d, which is two strokes behind the first cylinder 1a, communicates with the fourth bypass passage 15d on the upstream side of the rotary valve 18, and the intake air is transferred to the fourth bypass passage 15d. Since air is supplied from the passage 15d to the first bypass passage 15a via the intake air supply passage 2o in the rotary valve 18, the configuration can be simplified by eliminating the need for other piping.

In the above embodiment, the ignition timing is controlled according to the engine load, but the air-fuel ratio and the amount of exhaust gas recirculation for exhaust gas purification may also be controlled.

(Effects of the Invention) As explained above, the intake air 1iIW of the engine of the present invention
According to 1, at low loads when it is difficult to accurately detect the intake negative pressure, the engine load is determined independently of the intake negative pressure based on the opening timing of the rotary valve corresponding to the intake air amount and the engine speed. This makes it possible to detect the engine load with high precision, making it possible to control the ignition timing and air-fuel ratio according to the engine load, and improve the @R degree.゛1 It is preferable.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a cross-sectional view when applied to an intake system of a four-cylinder engine, FIG. 2 is a cross-sectional view taken along the line IF-It in FIG. 1, and FIG. FIG. 4 is a diagram showing the opening characteristics of valves and shutter valves with respect to increases in accelerator pedal opening. FIG. 4 is a diagram showing an ignition timing map stored in the ignition timing control t111 device. 1... Engine, 2... Combustion chamber, 5... Intake valve,
10a-10d...Intake passage, 11a-11d...
Shutter valve, 158-15 (1... bypass passage, 18... rotary valve, 18a... opening, 20
...Intake supply passage, 23...Planetary gear mechanism, 45
...opening sensor, 46...rotation speed sensor, 47...
- Load detection means, 48... Ignition timing l1IJ control device. Patent applicant Mazda Motor Corporation

Claims (1)

[Claims] (1) A shutter valve disposed in an intake passage to open and close the intake passage, and a rotary valve disposed in a bypass passage bypassing the shutter valve to open and close the bypass passage, and the shutter valve operates in a low load range. An intake system for an engine, wherein the rotary valve is closed during the intake stroke and the closing timing of the rotary valve is delayed in accordance with an increase in the accelerator pedal opening. The present invention is characterized by comprising a valve opening timing detection means for detecting the engine speed and a rotation speed detection means for detecting the rotation speed of the engine, and the load detection means for detecting the engine load by the valve opening timing detection means and the rotation speed detection means. The intake system of the engine.