JPS6332122A - Variable swirl generating device - Google Patents

Abstract

PURPOSE:To improve the acceleration responsiveness by installing a swirl generating valve on the downstream side of a fuel injection valve in a suction passage and controlling the swirl generation valve so that the flow passage area is reduced when the load is small and delaying the operation for increasing the flow passage area when the load sharply increases. CONSTITUTION:A shutter valve 10 as a variable swirl generating valve which turns around a shaft 18 is installed onto the downstream side of a fuel injection valve 12 on the upstream side of an intake port 14. The shutter valve 10 is connected with the diaphragm 27 of a vaccum motor 21 through a link 19, and opened and closed by the negative pressure of an intake manifold 9. A valve opening delaying means consisting of an orifice 24 and a check valve 25 is installed into a negative pressure pipe 23. Therefore, when a throttle valve is opened in engine acceleration, the reduction of the negative pressure is transmitted to a vacuum motor 21, and the fuel adhering onto the suction pipe is splashed off by throttling the intake stream in the initial stage of acceleration, and the lean conversion in acceleration is prevented, and the acceleration responsiveness can be improved.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention causes timely swirl generation in the intake air flowing into the combustion chamber from the intake boat side. The present invention relates to a variable swirl generating device that generates a variable swirl by narrowing the area using a swirl generating valve.

(Prior Art) It is believed that generating swirl within a combustion chamber is effective in improving the combustion characteristics of an internal combustion engine, and various swirl generating devices have been proposed. In particular, the inner wall of the intake port is formed into a spiral shape, and the school generation valve just in front of the intake port allows
A variable swirl generating device is known that efficiently generates swirl by restricting intake air to flow into a combustion chamber only during medium to low load operation.

For example, in the case of a variable swirl generator that is combined with a fuel supply system that uses a multi-point injection system as shown in Fig. 9, a 7 Yatsuta valve 3 is installed at the upstream end of the intake port 2 formed in the cylinder head 1. Furthermore, the intake flow bar is adjusted by the throttle valve 4 on the upstream side.

In this case, the shutter pulp 5 is held at the swirl generation position shown by the solid line by an appropriate valve 1 driving means during medium and low load operation, and when switching to higher load operation, it is immediately switched to the open position shown by the VC double-dashed line. This enables high-load operation with a large intake air volume.

By the way, if the above-mentioned fuel injection valve 5 is arranged, for example, on the downstream side VC of the shutter valve 5 shown by the two-dot chain line, the responsiveness of fuel supply to the combustion chamber will be improved.

However, in this case, the VC fuel injection valve 5 is placed very close to the shutter valve 6 (due to layout restrictions), and the fuel particles hit the shutter valve 5, making it impossible to spray smoothly. Moreover, this injection valve 5 itself also has the problem of being susceptible to heat damage.

(Problem to be Solved by the Invention) Therefore, if the fuel injection valve 5 is arranged upstream of the shutter valve 6 as shown by the solid line in FIG. As shown in Figure 10 (a) VC, the intake manifold 6, the intake boat (not shown) or the shutter valve 3 are relatively far from the combustion chamber, which tends to cause problems in the responsiveness of fuel supply. As a result, the amount of fuel adhering to the combustion chamber increases rapidly at the beginning of load fluctuations, which tends to cause the combustion chamber to become full and the acceleration response to deteriorate.

Here, as shown in Figure 3-8, when the shutter valve 6 is opened at the same time as the opening of the 5Vc throttle valve 4 (indicated by a dashed line), the shutter valve 6 is kept open at all times. When the shutter valve 3 is opened (indicated by the two-dot chain line), when the shutter valve 6 is normally closed (indicated by the broken line), and when the opening operation of the shutter valve 3 is delayed by a predetermined period from the time To when the valve starts opening (indicated by the solid line). Air-fuel ratio A/ of each combustion chamber in [shown]
F was measured. From this result, it has become clear that at the start of acceleration, if the gloss valve is normally closed or if the Pfr is delayed for a certain period of time and then opened, it is possible to suppress the combustion chamber alignment the most. This is figure 10 (b)
As shown in the figure, by narrowing down the shutter valve 3 at the beginning of a sudden increase in the amount of intake air, a large amount of intake air flow blows off the liquid film of fuel that adheres to the inner wall, thereby preventing a drop in the degree of fuel immersion in the air-fuel mixture. It is considered that this is because the effect works.

An object of the present invention is to provide a variable swirl generating device that can generate swirl in a timely manner without reducing the acceleration response of an internal combustion engine.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention reduces the flow path area of intake air flowing into the intake boat by a swirl generating valve installed downstream of the fuel injection valve in the intake path. When the load of the internal combustion engine is small, the flow passage area is narrowed by the valve driving means, and when the load is large, the flow passage area is increased by the valve driving means. A configuration is adopted in which the flow passage area increasing operation by the swirl generating valve is delayed by a predetermined period of time before being performed.

(When the load is low, the swirl generation valve throttles the intake air to improve the swirl generation effect, and when the load is large, the swirl generation valve opens and allows a large amount of intake air to flow in. Especially at the start of acceleration. Furthermore, the delay time acts to keep the swirl generating valve in a constricted state so that a large amount of intake air passing between the valve and the inner wall of the intake passage blows off the fuel adhering to the inner wall of the intake passage towards the combustion chamber side.

(Embodiment) The swirl generating device shown in Fig. 1 is equipped with a shutter valve 10 as a swirl generating valve, and a valve driving means 11 that drives the shutter valve by a double-machine operation, and has a multi-point injection system. The intake system is installed in the intake system of the Ganlin engine (not shown) together with the fuel injection valve (hereinafter simply referred to as the injection valve) 12 of the fuel supply system (not shown) that adopts a fuel supply system (not shown). A boat 14, a spacer 15, an intake manifold (hereinafter simply referred to as intake manifold) 9, and an intake passage 16 that is continuously formed on the side of an air cleaner (not shown).
It consists of.

The inner wall surface of the intake boat 14 has a spiral shape, which gives a swirling characteristic to the intake flow passing through the gap t between the shutter valve 10 and the inner wall of the intake passage, especially during low load as will be described later. Its shape is set so that when the intake air flow flows into the combustion chamber 17, a swirl can be generated smoothly.

The shutter valve 10 is fixed to the base end side of the rotating shaft 18Vc which is pivotally supported by the spacer 15, and the rotating end is located between the closed position P1, which is the pulse swirl generation position, and the open position P2, which is the retreating position. It is rotatable. Spacer 15
A valve,
A driving means 11 is connected.

The valve driving means 11 includes a vacuum motor 21 connected to the link 19 via a connecting rod 20;
Negative pressure pipe 2 that guides intake manifold negative pressure PIM to the negative pressure chamber 22 of
3, an orifice 24 as a valve opening delay means disposed in the middle of the negative pressure pipe 26, and a check 9f25.

The negative pressure chamber 22 of the vacuum motor 21 is formed by a case 26 and a diaphragm 27, and a compression spring 28 housed inside presses the diaphragm 27 in the valve opening direction (downward). Note that the compression spring 28 used has an elastic force that can maintain the pressure at atmospheric pressure.

The reverse valve 25 and the orifice 24 are attached to a partition wall 29 that cuts off the flow path of the negative pressure chamber 25 from front to back. Of these, check valve 25
prevents air from flowing into the negative pressure chamber 22 and allows air to flow out. The orifice 24 is formed in a shape that is sufficiently narrower than the opening amount of the reversal valve 25, and provides sufficient flow resistance to the gas flowing between the intake passage 16 and the negative pressure chamber 22, that is, equal pressure deadness between the two. a predetermined delay time (for example, td in Figure 2)
].

A surge tank 60 is formed on the upstream side of the intake manifold 9,
A throttle valve 31 is installed upstream thereof.

It is assumed that an engine equipped with such a variable swirl generating device is being driven, and a vehicle traveling section (not shown) is being performed. At this time, the valve opening start point To from the middle and low load area E1
Assume that when the load is reached, an acceleration operation is performed (see Figure 2), and the throttle valve 31 increases its opening degree θ to the high load range E2 side. Then, although the negative pressure values of both the negative pressure chamber 22 and the intake passage 160 were equal until time TO, a difference occurs between them due to the action of the orifice 24 as a valve opening delay means and the reversal valve 25, and this state changes to Continues until T1. During this time,
First, the intake manifold negative pressure PIM lowers the negative pressure value in conjunction with the throttle valve opening θ, and stabilizes the value at time T2.

On the other hand, the decrease in the negative pressure chamber pressure Pa is delayed, and at the time T3 when the negative pressure chamber pressure Pa reaches the specified temperature value ΔPK relative to the atmospheric pressure, the shutter valve 10 completes switching from the closed position MP1 to the open position P2. In this way, from time T2 to T6
The time width until the shutter valve 10's delay time td
Therefore, from time T2 to T6, the shutter pulp is 1G even though the throttle valve 31 is open.
is closed, and the gap t between this valve and the inner wall of the intake passage 16
A large amount of air flows through the gap (see Figure 10 (b)), and the liquid film of fuel layered near this gap is transferred to the combustion chamber 17.
Blowing to the side -r0 As a result, during the delay time td, the fuel accelerated and increased is sprayed from the injection valve 12, and even if it forms a liquid film on the intake manifold 9, shutter valve 10, or intake boat 14 wall. This can be mixed into a large amount of intake air flow, and the leanness of the combustion chamber 17 at the start of acceleration can be sufficiently reduced compared to the conventional case. That is, the characteristics are close to those shown by the solid line in FIG.

Figures 1 and 6 show a variable swirl generating device as another embodiment of the present invention. This device is equipped with negative pressure pipe 25 in Figure 1.
They have the same structure except that the orifice 24 and check valve 25Vc are used instead of the orifice 24 and check valve 25Vc as the valve opening delay means attached to the valve, and a pair of solenoid valves 33 and 34 and a controller 55 that controls these valves are used. The explanation is omitted.

The variable school generator of the 3rd figure is Shanotaba.

Lupu 10? : The vacuum motor 21v in the valve driving means 11 is driven by the negative pressure of the intake passage 16. This intake passage includes a solenoid valve 63 that opens the passage of the negative pressure pipe 26 when it is on and closes it when it is turned off, which communicates the passage of the negative pressure pipe with the negative pressure chamber 22 when it is turned on, and opens the negative pressure chamber 22 to the atmosphere when it is turned off. However, a second electromagnetic valve 64 for closing the negative pressure pipe flow path is installed.

The controller 35 that drives both electromagnetic valves is formed by a microcomputer, and this computer includes a vehicle speed sensor 36 that outputs vehicle speed information, a throttle opening sensor 67 that outputs throttle opening information, and intake manifold negative pressure. An intake manifold negative pressure sensor 38 that outputs information and an engine rotation sensor 39 that outputs engine rotation information are connected. In addition, in order to obtain load information instead of the intake manifold negative pressure information, the engine rotation sensor 3 is used as shown by the two-dot chain line.
9 and intake air amount information? An output air amount sensor 40 may also be used.

In place of the function of the valve opening delay means in the first embodiment, the controller 35 in the valve driving means 11 first functions as a valve opening delay region determining section for determining whether or not the current operating region is in the valve opening delay region C. It also has a function as a delay time calculation unit that calculates the valve opening delay time td, and also functions as a valve and drive control unit that switches between the two solenoid valves according to the functions of the above two functions. (See Figure 3-6). For this reason, the computer's ROM (read-only memo', l) K contains the engine speed N and intake manifold negative pressure PIM (or intake flow rate A/N in some cases) as shown in Figure 1'4 (a). Calculate the valve opening delay time output map for calculating the valve opening delay range C determined by [2], and the delay time td determined from the engine speed N and intake manifold negative pressure PIMVC as shown in Figure 4 (b) VC. The maps for each are memorized.

A control program for the computer in the controller 65 is shown in FIG.

When this control program starts, first, various data such as single engine, engine speed, throttle opening, and intake manifold negative pressure are taken in -lA.

In addition, the throttle opening θ is determined by a time interruption of a predetermined width.
The differential values dθ/dt (angular velocity in the opening operation of the valve) are sequentially taken in, and these are replaced in a predetermined memory area and processed.

Moreover, the spear 2 solenoid valve 64 has an engine rotation speed N of the specified value M.
Figure j-4 (a) Threshold value of engine speed indicated by VC)
When Nl exceeds 7, it turns off and keeps the valve 64 in the open position P2 Vc, and when it falls below it, it turns on and closes the valve 64 in the closed position P.
In order to maintain 1K, an unillustrated 2-magnetic valve driving routine is executed by a time interrupt.

Proceeding to step a2 tic, here is the engine rotation speed N, intake manifold negative pressure PIMY, valve opening delay area calculation map Vc
Then, it is determined whether the current operating range is in the valve opening delay range C or not. And when it is in the medium and low load range E1, step a
6 Vc1 Conversely, the valve opening delay region C, which is the high load region E2
If so, proceed to step a4.

Here, when step a3Vc is reached, that is, in the middle and low load range E1, the opening operation of the throttle valve at that point is set to the specified value α (a threshold value for determining that acceleration has started, which is set in advance). First, if it is small, proceed to step a5, reset the timer (not shown) in the computer, and wait for the start.Then, start acceleration in the current driving range. Later delay time td
i Fang 4 (b) A three-dimensional map as shown in VC, that is, ta
= f(N, P, .), then the first Kameda valve 66 is kept on and the process returns.

The process goes to step a6 again, and when dθ/dt exceeds α and acceleration begins, that is, the black line in Figure 5 passes through time T4, the process proceeds to step a8. At this point, the timer is turned on and the latest delay time determined at the present time is also started counting dn. Furthermore, spear 1 solenoid valve 66
is turned off, that is, the shutter valve 10 is held in the closed position P1vc, and the process returns.

Step a2 is reached again, and the valve opening delay range CK current operating range has been reached (passing time T4 in Figure 5), the process advances to step a4 and the timer count reaches td.
It is determined whether or not it has exceeded n, it waits for a time, and if it has exceeded it (passed time T5), it proceeds to step a10.
The spear 1 solenoid valve 66 is turned on, and the negative pressure chamber 2 is passed through the negative pressure pipe 23.
2, the gas from the intake passage 16 side is caused to flow in, that is, the negative pressure is lowered, and the compression spring 28 moves the Nyasota valve 10 to the open position P2 and holds it there.

Due to the delayed opening operation characteristic of the soyanta valve 10, the decrease in the amount of fuel supplied to the combustion chamber 17 at the beginning of acceleration can be prevented.
The blow-off effect of the fuel liquid film (see FIG. 10(b)) can be further prevented, and furthermore, after the delay time has elapsed, the shafter valve can be fully opened immediately to ensure a sufficient amount of intake air.

As a result, the acceleration response of an engine equipped with such an intake system can be improved.

In addition, symbols (1) to (2) in Fig. 3-5 respectively indicate waveform diagrams of different accelerations, throttle opening θ based on mode vc, shutter valve operation, and throttle valve angular velocity dθ/dt. Further, the symbol d indicates the actual delay time.

In the above, a pneumatic actuator was used as the valve drive means, but instead of this, a link 19VC direct renoid (not shown) of the Nyanota valve was used.
The valve driving means 11 may be configured by connecting the movable iron core side of the valve and driving the renoid with a controller similar to the controller 65 described above. In this case as well, the same effect as that of the variable swirl generator shown in FIGS. 3-6 can be obtained.

(Effects of the Invention) Since the swirl generation valve that generates swirl when the load is small is opened a predetermined delay time after the start of acceleration, the fuel liquid film adhering to the inner wall of the intake passage is removed at the start of acceleration. A large amount of intake air can be blown and supplied to the combustion chamber, and it is possible to prevent a drop in acceleration response due to uniformity at the start of acceleration.

[Brief explanation of drawings]

Figure 1 and Figure 6 are schematic configuration diagrams of variable swirl generating devices as embodiments of the present invention, Figure 2 is a waveform diagram explaining the operating characteristics of the device in Figure 1, Figure 4 is a), (
b) l is a conceptual diagram of a map for calculating valve opening delay generation and a map for calculating delay time used in the controller in the back of Figure 3;
Figures 1 and 5 are waveform diagrams explaining the operating characteristics of the device in Figure 6.
Figure 6 is a block diagram of the valve driving means used in the device shown in Figure 6, Figure 7 is a flowchart of the control program used in the device shown in Figure 6, and Figure 8 is a diagram of the entire combustion chamber according to various types of shutter pulp. Fuel ratio A/F temporal change characteristic diagram 1, t-
Figure 9 is a sectional view of the main parts of a conventional variable swirl generating device.
Figure 1 (a) shows an explanatory view of the action of each shutter pulp in the conventional device, and Figure 10 (b) shows the action of each shutter pulp in the device of the present invention. 10...Shutter pulp, 11...Valve driving means, 1
2... Injection valve, 14... Intake boat, 16... Intake path, td... Delay time. Side 1 Figure 2 Figure b Figure y Figure 4

Claims (1)

[Claims] A swirl generating valve is installed downstream of the fuel injection valve in the intake path and changes the flow path area of intake air flowing into the intake port.It narrows the flow path area when the internal combustion engine load is small, and conversely when it is large. and valve driving means for driving the swirl generating valve to increase the flow rate, and the valve driving means causes the swirl generating valve to perform an operation to increase the flow passage area after a predetermined time delay when the load increases rapidly. A variable swirl generating device characterized by: