JP2894028B2 - Intake control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake control system for a double intake valve type internal combustion engine used in a four-wheel drive vehicle with a sub-transmission.

[0002]

2. Description of the Related Art Both a part-time four-wheel drive vehicle that can select two-wheel drive and four-wheel drive, and a full-time four-wheel drive vehicle that is always four-wheel drive, require a low-speed four-wheel drive when climbing a slope or traveling on a rough road. During driving, an auxiliary transmission may be provided to further reduce the gear ratio selected by the main transmission in order to increase the torque.

[0003] In recent years, such a four-wheel drive vehicle sometimes employs a double-intake-valve internal combustion engine that achieves low fuel consumption at low speeds and high output at high speeds in consideration of general road driving. ,
The intake control device has a straight port provided with an intake control valve, and a helical port for generating swirl in the combustion chamber.

Japanese Utility Model Laid-Open Publication No. Sho 62-43135 discloses a system in which the intake control valve of such an intake control device is fully closed in the widest possible range according to the throttle opening and the rotational speed of the internal combustion engine. Have been.

Since the intake control valve is fully closed as described above, most of the intake air can pass through the helical port and form a strong swirl flow in the combustion chamber. Can be burned, and fuel efficiency can be reduced within this wide range. Also, in the high-speed and high-load region of the internal combustion engine exceeding this range, the intake control valve is fully opened, whereby a large amount of intake air is supplied to the combustion chamber through both ports, and the charging efficiency is improved, and a high torque is obtained. Can be

[0006]

When such an intake control device is applied to a four-wheel drive vehicle as described above, a high-speed four-wheel drive mode and a high-speed two-wheel drive mode selected when traveling on a general road by a sub-transmission. In this mode, low fuel consumption and high output can be obtained as described above, but the straight port is closed by the intake control valve in the low-speed four-wheel drive mode in which the gear ratio is further reduced by the sub-transmission and uphill and rough road running are performed. Increase in intake resistance due to
Sufficient torque cannot be obtained.

As a result, in order to obtain a desired torque, the accelerator pedal must be depressed more than necessary, which causes not only poor drivability but also poor fuel economy.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an intake control device for a double intake valve type internal combustion engine in which a sufficient torque can be obtained in a low-speed four-wheel drive mode in a four-wheel drive vehicle with an auxiliary transmission.

[0009]

In order to achieve the above-mentioned object, an intake control system for an internal combustion engine according to the present invention comprises a double intake valve system having a sub-transmission capable of selecting at least a low-speed and a high-speed four-wheel drive mode. Used in internal combustion engine four-wheel drive vehicles,
A straight port provided with an intake control valve, a helical port for swirl generation, and as wide as possible depending on the rotational speed and load state of the internal combustion engine except when the low speed four-wheel drive mode of the auxiliary transmission is selected. The intake control valve is fully closed in the range, and when the low-speed four-wheel drive mode of the subtransmission is selected, the intake control valve is fully opened or the intake control valve is fully closed only in a range considerably smaller than the range. And an intake control valve control means.

[0010]

When the low-speed four-wheel drive mode is selected by the auxiliary transmission, the intake control device for the internal combustion engine described above operates in the widest possible range according to the rotational speed and load condition of the internal combustion engine other than the mode. Unlike the control in which the control valve is fully closed, the intake control valve requires a relatively large torque, such as climbing a slope or running on a rough road, because the intake control valve is fully closed or fully closed only in a range considerably narrower than the above range. In this mode, the intake air is supplied using both ports, except at all times or at a considerably low speed and low load, so that the intake resistance is reduced and sufficient torque is obtained as compared with the conventional system using only the helical port. Can be.

[0011]

FIG. 1 is a schematic diagram showing an embodiment of an intake control device for an internal combustion engine according to the present invention. In FIG. 1, reference numeral 1 denotes a double intake valve type internal combustion engine, which has an exhaust port 2 via both exhaust valves (not shown), and a helical port 3 and a straight port 4 via each intake valve (not shown). Are connected. The helical port 3 and the straight port 4 integrally communicate with the surge tank 5 on the upstream side, and the surge tank 5 is connected to an intake passage 7 having a throttle valve 6.
It communicates with an air cleaner (not shown).

The straight port 4 is provided with an intake control valve 8, and an integral part of the ports 3, 4 is provided with a fuel injection device 9 for injecting fuel in synchronization with intake. Thereby, when the intake control valve 8 is closed, most of the intake air becomes a mixture with the injected fuel, passes through the helical port 3, and forms a swirl flow of the mixture in the combustion chamber.
Due to the effect of improving the combustion of the swirl flow, even if the formed air-fuel mixture is a lean air-fuel mixture, it is satisfactorily burned and low fuel consumption operation is realized. If the intake control valve 8 is opened, a large amount of intake air can be supplied to the combustion chamber by using the ports 3 and 4, and a high torque can be obtained by improving the charging efficiency.

The opening and closing of the intake control valve 8 includes a throttle opening sensor 10 for detecting the opening of the throttle valve 6, a rotation sensor (not shown) for detecting the rotation speed of the internal combustion engine 1,
The operation is performed by an actuator 14 that is operated by an electric signal of a CPU 13 electrically connected to an auxiliary transmission 12 provided separately from the main transmission 11 in the four-wheel drive vehicle.

The CPU 13 operates the actuator 14 according to one of the two flowcharts shown in FIG. 2 to control the opening and closing of the intake control valve 8. In the first flowchart shown in FIG. 2A, first, it is determined whether or not the auxiliary transmission 12 is in a low-speed four-wheel drive mode in which the gear ratio selected by the main transmission 11 is further reduced. Controls the opening and closing of the intake control valve 8 in accordance with the throttle opening detected by the throttle opening sensor 10 and the rotation speed of the internal combustion engine detected by the rotation sensor according to a map A shown in FIG. In the mode, the intake control valve 8 is fully opened.

The second flowchart shown in FIG.
Similarly, after determining whether or not the mode is the low-speed four-wheel drive mode, when the mode is not this mode, it is the same as the first flowchart in FIG. 2A, but in this mode, according to the map B shown in FIG. The opening and closing of the intake control valve 8 is controlled in accordance with the throttle opening and the rotational speed of the internal combustion engine.

A map A in FIG. 3 is a map in which the intake control valve 8 is fully closed in a wide range as much as possible according to the throttle opening and the rotational speed of the internal combustion engine. Intake control valve 8 only in low load range
Is a map for fully closing.

The intake control apparatus for an internal combustion engine according to the present embodiment has the above-described structure, and the intake control valve 8 is controlled to open and close in this manner. When driving on a general road other than the selected road, the intake control valve 8 is fully closed in a considerably wide area surrounded by the map A as in the related art, and low fuel consumption driving using swirl can be realized. In high load areas,
The intake control valve 8 is fully opened, so that a high torque can be obtained by using both ports to improve the charging efficiency.

When the low-speed four-wheel drive mode is selected by the sub-transmission when climbing a hill or traveling on a rough road, FIG.
According to the first flowchart shown in (A), the torque is required by the full opening of the intake control valve 8 except in the low-speed, low-load side range, which is rather narrow, according to the second flowchart shown in FIG. In the traveling, since intake air is supplied from both ports to the combustion chamber, intake resistance is reduced, charging efficiency is increased, and required torque can be obtained.

In this embodiment, a throttle opening sensor is used as one means for knowing the load condition of the internal combustion engine. In addition, the amount of air (Q /
N), it is also possible to use a sensor for detecting any one of the intake pipe negative pressure, the fuel injection amount, the intake air amount and the like.

[0020]

As described above, according to the intake control system for an internal combustion engine according to the present invention, when a four-wheel drive vehicle travels on a general road, low fuel consumption and high torque operation can be performed as in the conventional case, and the vehicle can be climbed uphill. And when traveling on rough roads, if the low-speed four-wheel drive mode is selected by the auxiliary transmission, the intake control valve
Since the intake air is supplied to the combustion chamber through both ports at all times except when the vehicle is in a normal state or in a range other than a considerably low speed and low load side, the intake resistance is reduced, and sufficient torque required at that time can be obtained.

As a result, the accelerator pedal is not depressed more than necessary at this time, so that not only the drivability is improved but also the fuel efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an intake control device for an internal combustion engine according to the present invention.

FIGS. 2A and 2B are flowcharts in which one of them is used for controlling an intake control valve according to the present invention. FIG. 2A is a first flowchart, and FIG. 2B is a second flowchart.

FIG. 3 is a map that is used in the flowcharts of FIGS. 2A and 2B and that opens and closes an intake control valve in accordance with a throttle opening and a rotation speed of an internal combustion engine.

[Explanation of symbols]

 3 ... Helical port 4 ... Straight port 6 ... Throttle valve 8 ... Intake control valve 12 ... Sub-transmission 13 ... CPU 14 ... Actuator

Claims (1)

(57) [Claims] 1. A straight port provided with an intake control valve for use in a four-wheel drive vehicle of a double intake valve type internal combustion engine having an auxiliary transmission capable of selecting at least a low speed and a high speed four wheel drive mode, and a swirl generation. Helical port for, except when selecting the low-speed four-wheel drive mode of the auxiliary transmission,
The intake control valve is fully closed in the widest possible range according to the rotational speed and load state of the internal combustion engine, and when the low-speed four-wheel drive mode of the auxiliary transmission is selected, the intake control valve is fully opened or fixed. An intake control valve control means for fully closing the intake control valve only in a range considerably smaller than the range.