JPH04109030A - Variable intake device for car - Google Patents

Abstract

PURPOSE:To improve transient response at acceleration by positioning a throttle valve whose opening degree is set according to a step-down amount of an accelerator pedal close to an intake port against an intake control valve in a longer passage of intake passages different in length. CONSTITUTION:An intake passage 4 connected to, for example, an intake port 1B which communicates to a combustion chamber 1A of an engine body 1 for V-type six cylinders is provided with an air cleaner 7, a variable intake device 8 and a fuel injection device 9 from the upstream along the intake direction, and the variable intake device 8 is provided with a first passage 8B which is thick and short in the passage length and a second passage 8D which is thin and long in the passage length are combined in parallel between an outlet of a surge tank 8A and the intake port 1B. Here, an intake control valve 10 driven by a stepping motor and so on is arranged in the first passage. And between the control valve 10 and the intake port 1B on the downstream side of the variable intake device 8 in the intake direction, throttle valves 11 are arranged to the number of cylinders whose opening degree is set according to a step-down amount of an accelerator pedal.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a variable intake system for automobiles, and more particularly to an on-off valve structure in an intake path having different lengths.

(Prior Art) Generally, in an automobile engine, in order to obtain good torque characteristics over a wide range from low speed range to high speed range,
There is one that employs an intake structure that utilizes intake inertia as shown in FIG.

That is, this structure combines in parallel a first passage A whose total length is lengthened to tune to a low-speed rotation range, and a second passage B whose total length is shortened to tune to a high-speed rotation range. The second passage forms an intake passage, and the second passage has a shorter overall length.
The intake control valve C is arranged in the passage.

With this structure, in the low speed rotation range, by fully opening the above-mentioned intake control valve C, intake air is supplied to the engine intake port using the intake inertia effect obtained when the intake path length is lengthened. In addition, by fully opening the control valve C in the high-speed rotation range, a large amount of intake air can be instantly introduced into the engine intake port through a short passage, improving intake efficiency over the entire rotation range. It is designed to optimize the

However, in the intake system having the structure described above, the fourth
As shown in the figure, the rotational speed at which the intake inertia effect is maximum differs between the low speed side and the high speed side. This will lead to the occurrence of troughs). Therefore, in the rotation speed range corresponding to this trough, the acceleration feeling due to torque fluctuation is reduced, resulting in poor driving feeling.

Therefore, in order to eliminate such problems, the opening degree of the intake control valve C mentioned above is continuously varied in accordance with changes in the engine speed in the intermediate speed range between the low speed range and the high speed range. A structure has been proposed in which the troughs of the torque curve are changed to a smooth state, thereby eliminating dips in torque.

(Problem to be Solved by the Invention) However, in such a structure, the above-mentioned intake control valve is located on the intake port side of the engine with respect to the throttle valve that is linked to depression of the accelerator pedal, in other words,
Because it is located downstream of the throttle valve in the intake direction, steady torque can be improved by utilizing the length of the intake system, but on the other hand, it is difficult to press the accelerator hard to accelerate from a steady state. If so,
Due to the length of the intake system, in other words, the volume downstream of the throttle valve is large, the transient response characteristics regarding the intake air filling efficiency are deteriorated. In addition, with this type of structure, if a load change occurs, such as when operating the air conditioner or power steering during idling, the intake air cannot be filled immediately to meet the load, resulting in a significant drop in rotational speed. Sometimes it happened.

SUMMARY OF THE INVENTION In view of the above-mentioned problems with the conventional variable intake system, an object of the present invention is to provide a variable intake system that can improve transient response characteristics during rapid acceleration from a steady state.

(Means for Solving the Problems) In order to achieve this object, the present invention provides an engine main body,
The intake passage of the engine body is constructed by combining passages of different lengths in parallel, and the intake passage on the short side of this intake passage is fully closed at low speeds. In the high speed range, the fully open position is set, and in the intermediate speed range corresponding to the maximum torque generating section that occurs when air is taken in from the passages of different lengths, the engine speed changes according to the engine speed. an intake control valve that can be opened and closed and whose opening degree is set according to the amount of depression of the accelerator pedal; It is characterized by being equipped with a throttle valve that sets the amount of intake air.

Further, the present invention is characterized in that throttle valves are provided in accordance with the number of cylinders.

Furthermore, the present invention is characterized in that an idle speed controller is provided in parallel with the throttle valve.

(Function) According to the present invention, by shortening the distance between the throttle valve and the intake port of the engine cylinder, the same effect as reducing the volume downstream of the throttle can be achieved, thereby improving the accelerator response during acceleration. Along with improving
Combined with the inertial effect of variable intake, the acceleration feeling can be improved. Additionally, when load fluctuations occur during idle rotation, the idle speed controller introduces intake air from the intake passage when the throttle valve is fully closed, thereby quickly reducing the negative pressure in the intake passage. This makes it possible to reduce the decrease in rotational speed.

(Embodiment) Hereinafter, details of an embodiment of the present invention will be explained with reference to FIGS. 1 and 2.

The feature of this embodiment is that the variable intake structure includes an intake passage formed by parallel passages of long and short lengths, and an intake control valve that controls the opening/closing of the longer passage of the intake passage. A throttle valve is placed between this valve and the intake boat of the engine body on the downstream side of the engine.

That is, in FIG. 1, reference numeral 1 indicates an engine body, and this engine body 1 is, for example.

It is composed of engine parts such as a cylinder block 2 formed for a V-type six cylinder and a cylinder head 3 having a valve train arranged on the head thereof.

An intake passage 4, which will be described later, is connected to the intake boat IB that communicates with the combustion chamber IA of the engine main body 1, and an exhaust boat IC that communicates with the combustion chamber IA has, for example, a three-way catalyst device 5 and a An exhaust path 6 with a muffler interposed in the middle is connected.

The above-mentioned intake passage 4 is equipped with an air cleaner 7, a variable intake device 8, and a fuel injection device 9 from the upstream side along the intake direction indicated by the arrow in the figure.

The variable intake device 8 described above has a first passage 8B which is thick and has a short passage length and a first passage 8B which is narrow and has a long passage length between the outlet of the surge tank 8A that constitutes the intake system and the intake boat IB in the cylinder head 3. The air intake passage 8D is formed by combining two passages 8C in parallel.

Each of these passages is connected to the intake passage 4, and then branched and connected to the intake port IB of each cylinder.

Of the above-mentioned passages, an intake control valve 10 driven by a rotation drive means such as a stepping motor (not shown) is disposed in the first passage. Fully open position depending on the rotation speed range,
It is possible to change the opening degree continuously between the fully closed position and each of these positions.

In other words, the intake control valve 10 is set to the fully closed position in the low-speed rotation range to introduce intake air into the combustion chamber via the second passage 8C, and in the high-speed rotation range, The first passage 8B is set in the fully open position.
The intake air is introduced into the combustion chamber through the combustion chamber.

Further, in an intermediate rotation speed range between these respective rotation speed ranges, the opening degree is set in accordance with the rotation speed.

Therefore, in low speed ranges, intake air is introduced through the second passage 8C, making efficient intake air possible by utilizing intake inertia, and in high speed ranges, a large amount of intake air is instantly supplied. Furthermore, in the intermediate rotation speed range, continuous opening settings are used to reduce fluctuations in intake air amount and suppress drop in torque.

On the other hand, on the downstream side of the variable intake device 8 in the above-described intake direction, a throttle valve 1 whose opening degree is set according to the amount of depression of the accelerator pedal is arranged between the variable intake device 8 and the intake port IB.

That is, the throttle valves 11 are provided in accordance with the number of cylinders, and in this embodiment, six throttle valves are provided in line to correspond to the six cylinders.

Additionally, this throttle valve 11 is provided with an idle speed controller 12 for maintaining idle rotation, and this idle speed controller 12 has the following functions:
Intake path 4 and surge tank 8 downstream of throttle valve 11
The intake passage 12^ connected between A and this intake passage 12A
The solenoid valve 12B is located in the middle of the air conditioner, and the communication state is set when the power steering or air conditioner is started.

Since the present embodiment has the above-described structure, in a steady state, intake control corresponding to a low speed range, a high speed range, and an intermediate rotation speed range is performed by controlling the opening and closing of the intake control valve 10.

On the other hand, if the opening degree of the throttle valve 11 is set large by depressing the accelerator for acceleration from a steady state, the volume on the downstream side of the throttle valve 11 increases.

Since the passage length between the intake control valve 10 and the intake boat IB is shortened by tJs, the response regarding the intake air filling efficiency to the throttle opening setting becomes faster.

The results of this state obtained through experiments are shown in FIG.

In other words, Figure 2 shows the change in throttle opening and the change in volumetric efficiency in the intake passage corresponding to this change over time.When the throttle opening changes from fully closed to fully open, As shown by the solid line, the time required to reach a predetermined volumetric efficiency is faster than in the case of the conventional structure shown by the dotted chain line.

Furthermore, even when the load on the engine body fluctuates during idle rotation, the throttle valve 11
The negative pressure downstream of the throttle valve 11 is corrected in the direction of quickly decreasing due to the position of the idle speed controller 12 attached to the engine, thereby making it possible to reduce the drop in rotational speed in the engine body.

(Effects of the Invention) As described above, according to the present invention, when the foot of the accelerator pedal is pressed, the The throttle valve, whose opening is set accordingly, is located closer to the intake boat of the engine body, which improves the transient response when accelerating when the accelerator pedal is suddenly increased, so-called accelerator response. By combining the functions of the intake control valve described above, it is possible to expect a good acceleration feeling with no drop in torque. In addition, due to improved accelerator response, if auxiliary equipment such as the power steering or air conditioner is damaged during idle rotation, the intake path from the throttle valve to the intake boat via the idle speed controller attached to the throttle valve. Since the negative pressure inside the engine can be quickly reduced, it is possible to suppress the drop in rotation during idling.

[Brief explanation of drawings]

FIG. 1 is a model diagram of an engine intake system for explaining the overall configuration of a variable intake system for an automobile according to an embodiment of the present invention, and FIG. 2 is a schematic diagram for explaining the characteristics obtained by the configuration shown in FIG. 1. Figure 3 is a model diagram of an engine intake system for explaining the schematic configuration of a conventional variable intake system, and Figure 4 is a diagram for explaining the characteristics obtained by the configuration shown in Figure 3. It is. 1...Engine body, IA...combustion chamber, IB...
Intake boat, 2... Cylinder block, 3... Cylinder head, 4... Intake path, 8... Variable intake device,
8A...Surge tank, 8B...First passage, 8
C... Second passage, 8D... Intake path, 10... Intake control valve, 11... Throttle valve. Figure 2

Claims (1)

[Claims] 1. An engine body, an intake passage formed by combining passages of different lengths in parallel, provided in the intake section of the engine body, and a short passage in the intake passage. It is set in the fully closed position in the low speed range and in the fully open position in the high speed range, and the intermediate position corresponds to the maximum torque generating part that occurs when air is taken in from the passages of different lengths. In the rotation speed range, an intake control valve whose opening degree is set according to the rotation speed of the engine body, which can be opened and closed, and the intake section downstream of the intake control valve in the intake direction with respect to the intake section of the engine body. 1. A variable air intake system for a motor vehicle, characterized in that the variable air intake device for an automobile is equipped with a throttle valve that is arranged to set an air intake amount according to the amount of depression of an accelerator pedal. 2. The variable air intake system for an automobile according to claim 1, wherein the throttle valves are provided in correspondence with the number of intake sections of the engine body. 3. The variable air intake system for an automobile according to claim 1, further comprising an idle speed controller installed in parallel with the throttle valve.