JPS61112731A - Intake air device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve operating efficiency, in a valve for opening high speed- purpose intake air passage in the high speed range of the engine having two intake air valves for each cylinder, by gradually opening or closing the valve if a varying rate of engine speed is greater than that of a load and rapidly opening or closing the same valve if the latter is greater than the former, depending upon the result of the comparison between them. CONSTITUTION:A valve (h) which is opened in the high speed range of the engine is provided in high speed-purpose intake air passage (c) and is opened or closed by an actuator (k) in an engine having two intake air valves (a), (b) for each cylinder. Basic control is provided for the opening/closing valve (h) in accordance with an engine speed (e) but the opening/closing speed of the valve (h) is controlled by the result of the comparison between the varying rate of the engine speed (e) and that of load (f) with an arithmetic means (i). That is, the opening/closing valve is gradually opened or closed when the varying rate of the engine speed is great and it is rapidly opened or closed when the varying rate of the load is great.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a technique for improving the intake system of an internal combustion engine having two intake valves for each cylinder.

(Prior Art) As a prior art of the intake system of this type of internal combustion engine, there is one shown in FIGS. 6 and 7, for example (Japanese Patent Application
No. 8-225356).

This is a high-speed intake valve 1 with a large delay in closing timing for each cylinder.
A and a low-speed type intake valve 1B with a small delay in closing timing, and an on-off valve 3 is provided at the intake port 2A in which a high-speed type intake valve 1A is interposed, and the on-off valve 3 is closed in the low speed range of the engine and is closed in the high speed range. We are trying to open it in the area.

That is, in the low speed range, by taking in air only through the intake port 2B equipped with the low speed intake valve 1B with a small delay in closing timing, the effective compression ratio is increased and the intake air filling efficiency is increased. By creating a swirl in the combustion chamber by using the inflowing intake air flow, we aim to improve combustibility at low speeds.On the other hand, we also use the high-speed intake valve 1A, which has a large delay in closing timing at high speeds. By performing air intake, the inertial effect of air intake is effectively utilized, and by opening two intake ports, air intake resistance is reduced, intake air filling efficiency is increased, and output is improved.

Further, since the on-off valve 3 is opened less frequently in the normal operating range, the 7-well injector 4 is provided on the side of the intake port 2B, which is always open, in order to obtain stable air-fuel ratio control responsiveness.

Note that two exhaust valves 5A, 5B and two exhaust boats 6A, 6B are also provided.

(Problems to be Solved by the Invention) By the way, in an internal combustion engine equipped with such an intake system, when the on-off valve 3 is open and when it is closed,
Since the gas flow state within the combustion space differs greatly, the optimal ignition timing also changes significantly before and after 1FtIIW1.

When the on-off valve 3 is closed, the swirl in the combustion chamber is large, and when the intake valve 1B is closed, the combustion rate is relatively fast (near the bottom dead center) and the actual compression ratio is high, so the combustion speed is fast. For example, the optimal ignition timing is about 10 degrees before top dead center, but when the rotational speed increases from this state and the on-off valve 3 is opened, the swirl disappears and the actual compression ratio becomes low, causing combustion to slow down. Since the ignition timing will be delayed, the ignition timing must be advanced, for example, to about 20 degrees before top dead center.

However, in this case, since the opening/closing operation of the on-off valve 3 is fast, it is difficult to change the ignition timing at the same time as the on-off valve 3 opens and closes, in terms of responsiveness. It is designed to change. In the unlikely event that
If the ignition timing is advanced even by 0.1 seconds when the on-off valve 3 is opened from the closed state, severe knocking may occur, potentially damaging the engine.

However, if this is done, the ignition advance may be delayed too much depending on the operating conditions, and good combustion may not be maintained when the on-off valve 3 is opened, resulting in a significant decrease in engine torque. For this reason, it is unavoidable that the driver is given a shock that causes the vehicle to stall for a moment, resulting in a problem of deterioration in drivability.

This invention aims to solve the above-mentioned problems by controlling the opening/closing speed of the on-off valve 3.

(Means for Solving the Problems) This invention provides two intake valves a, b and two intake ports c, d for each cylinder as shown in FIG.
It is equipped with means e and f for detecting the rotational speed and load of lm, means q for determining operating conditions from these detected values, and an on-off valve for opening and closing one of the intake boats C according to the operating conditions. In internal combustion l1Il11, a means i for calculating the rate of change in the rotational speed and a rate of change in the load, a means J for comparing these rates of change, and when the rate of change in the rotational speed is large when opening and closing the opening/closing valve. The driving means is provided to gradually open and close the on-off valve, and to quickly open and close the on-off valve when the rate of change in load is large.

(Function) When the change in load is large relative to the change in rotational speed,
By quickly opening and closing the on-off valve, the amount of intake air is quickly opened and closed, and the amount of intake air is quickly increased or decreased. Therefore, a good output response can be obtained during acceleration and deceleration.

On the other hand, when the change in rotational speed is large relative to the change in load, the on-off valve is opened and closed slowly, so the swirl and the actual compression ratio change slowly. In other words, when the change in load is small, sudden changes in gas flow, etc. are suppressed, and therefore, a drop in torque due to valve opening and closing can be avoided without suddenly changing the ignition timing.

(Example) Figures 2 and 3 are a schematic overall configuration diagram and a main part configuration diagram showing an embodiment of the present invention, where 7 is an engine equipped with a turbocharger 8, and 1A and 1B are high-speed engines provided for each cylinder. 2A and 2B are intake boats thereof, and 3 is an opening/closing valve of the intake boat 2A corresponding to the high speed type intake valve 1A.

A rotating shaft 9 of this on-off valve 3 is connected to a diaphragm device 10 as an actuator, and a vacuum tank 14 is connected to the negative pressure chamber 11 via a three-way solenoid valve 12, 13.

Passages 18 and 19 are formed between the three-way solenoid valves 12 and 13 to connect the port 15 of the three-way solenoid valve 13 to the switching ports 16 and 17 of the three-way solenoid valve 12, and one passage 18 has an orifice with a large diameter. 2o, and the other passage 19 is provided with an orifice 21 having a smaller diameter.

Mikata NI! When the valve 12 is energized (ON), it opens the switching boat 17 and communicates the passage 19 with the negative pressure chamber 11 of the diaphragm device 10, and when the energization is cut off (OFF), it opens the switching port 16 and communicates the passage 18. It communicates with the negative pressure chamber 11.

Moreover, when the three-way solenoid valve 13 is energized (ON>, the boat 22 is opened and the passage 18.19 is communicated with the atmosphere, and when the energization is cut off (OFF), the boat 23 is opened and the passage 18.19 is connected to the atmosphere.
is communicated with the vacuum tank 14.

Engine suction negative pressure is stored in the vacuum tank 14 via the check valve 24, and when the boat 23 is opened by the three-way solenoid valve 12.13 and the passage 18 is selected, the negative pressure is applied to the orifice 2o. Diaphragm equipped! 11
0 into the negative pressure chamber 11, and the on-off valve 3 is immediately opened. At this time, when the passage 19 is selected, negative pressure is introduced into the negative pressure chamber 11 according to the orifice 21, and the on-off valve 3 is slowly opened.

In addition, the boat 2 on the atmospheric side is
2 is opened and the passage 18 is selected, the negative pressure in the negative pressure chamber 11 is released to the atmosphere according to the orifice 2o, and the on-off valve 3 is opened.
closes promptly. At this time, when the passage 19 is selected, negative pressure is released according to the orifice 21, and the on-off valve 3 is gently closed.

On the other hand, a rotational speed signal from the distributor 25 as means for detecting the rotational speed of the engine, and a pressure signal (load signal) from the intake pressure sensor 26b1 etc. as means for detecting the load are input to the control circuit 27. Further, 28 is an air 70-meter, 29 is a cooling water temperature sensor, 30 is an oxygen sensor, 31 is a knock sensor, etc., and these signals are also input to the control circuit 27.

Then, the control circuit 27 determines the operating conditions of the engine based on each signal, controls, for example, the fuel injection m from the fuel injection 4 and the ignition timing by the ignition device 32, and also controls the engine operating conditions based on the rotational speed signal and the load signal. The three-way solenoid valves 12 and 13 are driven and controlled according to the flow shown in FIG.

First, at 101.102, the rotational speed signal N and the load signal 1i4
P is read, and from this operating condition, the closed area and open area of the on-off valve 3, which are set as shown in FIG. 5, are determined in step 103.

Here, when the operating condition switches from the closed area of the on-off valve 3 to the open area, the process proceeds from 104 to 105, and when the operating condition changes from the open area to the closed area, the process proceeds from 104 to 106, and so on.

The rate of change in rotational speed dN/dt and the rate of change in load dP/
dt is calculated.

Then, in 107, these rates of change dN/dt and dP
/dt is compared, and when dN/dt is large, 10
At 8, the r three-way solenoid valve 12 is controlled to be turned on, and the three-way solenoid valve 13 is controlled to be turned off. Therefore, the negative pressure in the vacuum tank 14 is introduced into the diaphragm H10 through the orifice 21 of the passage 19, so that the on-off valve 3 is opened slowly.

When dpe”dt is large, the three-way solenoid valve 1 is activated at 109.
2.13 are both controlled to be OFF, so that the negative pressure in the vacuum tank 14 reaches the orifice 2 of the passage 18.
0, the on-off valve 3 is quickly opened.

On the other hand, when dN/dt is large at 110, three-way I! at 111! Both electromagnetic valves 2 and 13 are controlled to be turned on, and the negative pressure introduced into the diaphragm device 1ff10 is released to the atmosphere through the orifice 21 of the passage 19, so the on-off valve 3 is gently closed.

d When P/dt is large, three-way solenoid valve 1 is activated at 112.
2 is OFF and 13 is ON, so that the negative pressure introduced into the diaphragm device 10 flows through the passage 18.
Since the on-off valve 3 is opened through the orifice 20, the on-off valve 3 is quickly closed.

That is, when opening and closing the on-off valve 3 according to the operating conditions, when the change in rotational speed is large as shown in FIG.
The on-off valve 3 is opened and closed gradually, while when the change in load is large, the on-off valve 3 is opened and closed quickly.

In addition, 5A and 5B are exhaust valves, 6A and 6B are exhaust ports,
33 is a spark plug, 34 is an intake passage, 35 is a throttle valve, and 36 is an exhaust passage.

With this configuration, 1. For example, when the change in load is small and the change in rotational speed is large, that is, when only the rotational speed increases or decreases when the accelerator is near full open, the on-off valve 3 opens and closes slowly. The swirl in the combustion chamber 37 and the actual compression ratio gradually change before and after opening and closing.

For this reason, the optimal ignition timing also changes gradually, so it is possible to accurately avoid a drop in torque without suddenly changing the ignition timing before and after opening and closing the valve, and it is possible to maintain good drivability. can.

Note that when the on-off valve 3 is closed from the open state, the ignition timing tends to be advanced and there is a risk of knocking, but in this case too, the on-off valve 3 is gently closed to minimize the deviation in ignition timing. Therefore, the occurrence of knocking can be prevented.

On the other hand, when the change in rotational speed is small and the change in load is large, that is, when the accelerator is suddenly depressed after running at a relatively high speed, the on-off valve 3 is opened quickly. Therefore, the amount of intake air is quickly increased in response to the accelerator pedal, and
This makes it possible to ensure good acceleration response.

Note that in the deceleration state, the on-off valve 3 is closed in a continuous manner, so that similarly good responsiveness can be obtained.

(Effect of the invention) When opening and closing the on-off valve, when the change in rotational speed is large, the on-off valve is opened and closed gradually, and when the change in load is large, the on-off valve is opened and closed quickly. It is possible to prevent torque fluctuations during switching and ensure good engine performance and driving performance.

[Brief explanation of the drawing]

Fig. 1 is a complaint correspondence diagram, Figs. 2 and 3 are a schematic overall configuration diagram and a main part configuration diagram showing an embodiment of the present invention, and Fig. 4 is a flowchart 1 to 5 showing its control operation. is a graph showing an example of setting the opening/closing area of the opening/closing valve. @Figures 6 and 7 are a conventional configuration diagram of main parts and a diagram of opening characteristics of each valve. IA, IB...Intake valve, 2A, 2B...Intake boat, 3...Open/close valve, 5A, 5B...Exhaust valve, 10...
・Diaphragm equipment, 12.13...Three-way solenoid valve, 2
0.21...orifice, 25...distribution top l
-Evening, 26...Intake pressure sensor, 27...Control circuit. Patent Applicant: Nissan Motor Co., Ltd. Figures a, b-<fuben c, d ・-rohaitorukit °-to θ −・rotation reach mark kyoto means f −・yūku@'t:, hand fλ q -・-Installation F'1 Previous stage h -・-Opening/closing valve I ...Item 1 means j ・-・ rhiya 9:, 乎凭k ・-鈫'In t Jλ 5th Figure N (TI system - Figure 6

Claims (1)

[Claims] Each cylinder is equipped with two intake valves and two intake ports, and also includes a means for detecting the rotational speed and load of the engine, a means for determining operating conditions from these detected values, and a means for detecting one intake port according to the operating conditions. In an internal combustion engine equipped with an on-off valve that opens and closes at a port, means for calculating the rate of change in the rotational speed and the rate of change in the load, and means for comparing these rates of change;
The present invention is characterized by providing a driving means for gradually opening and closing the on-off valve when the rate of change in rotational speed is large when opening and closing the on-off valve, and for opening and closing the on-off valve quickly when the rate of change in load is large. intake system for internal combustion engines.