JPS61169618A - Engine intake device - Google Patents

Abstract

PURPOSE:To improve fuel consumption and output under high land operation by regulating the intake air supply condition through control of a control valve arranged in heavy load intake path while correcting the opening of control valve is closing direction under high land operation and reducing the correcting amount as the load will increase. CONSTITUTION:Intake paths 5, 6 for heavy and light load are formed in the downstream of a throttle valve 4 in an intake path 3 and communicated through an intake valve 8 to the combustion chamber 2 upon confluence. While a control valve 9 to be controlled through a control unit 11 is arranged in the way of heavy load intake path 5. Upon detection of high land operation on the basis of the output from an atmospheric pressure sensor 15, the control unit 11 will control the opening of the control valve 9 to correct in closing direction. Here, the correcting amount is set to be lower as the engine load will increase. Consequently, combustion efficiency under low and intermediate load regions can be improved while avoiding droppage of output under heavy load region when operating on high land.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in an intake system for an engine having a low-load intake passage and a high-load intake passage equipped with a control valve.

(Prior art) Conventionally, a low-load intake passage and a high-load intake passage equipped with a control valve are formed, and when the load is low, the control valve is used to supply intake air from the low-load intake passage. According to
Combustion properties are improved by increasing the intake flow velocity and creating an intake swirl.At high loads, the control valve is opened to supply intake air from both intake passages, reducing intake resistance and suppressing intake swirl. The engine is known. In this type of intake system, the opening degree of the control valve is adjusted according to the load, engine speed, intake air gap, etc. so that intake air supply conditions such as intake flow velocity and intake swirl can be adjusted appropriately under various operating conditions. 1IJl! ll
There are also systems that correct the opening degree of the control valve during acceleration, etc. For example, in the device disclosed in Japanese Patent Application Laid-Open No. 59-60032, the opening degree of a control valve is controlled according to the venturi negative pressure or the output of an air 70-sensor, and the characteristics of the opening degree change are and during acceleration or deceleration, so that an appropriate intake air supply state can be obtained in each case.

By the way, this type of intake system costs $131 to suit normal lowland driving! The characteristics of the I valve have been determined again, but when operating at high altitudes, the opening degree of the throttle valve is wider (i.e., the opening angle is wider than when operating at low altitudes) to compensate for the lower air density Even in terms of output, the apparent load is thicker than the lower load (as a result, the control valve tends to open more than the appropriate opening degree, which tends to reduce combustion efficiency, especially in the low and medium load ranges). For this reason, it is desirable to correct the control valve in the opening direction during ground operation.

However, if the IIJ control valve is uniformly corrected in the opening direction over the entire operating range, the control valve will not fully open under load, which will create intake resistance and reduce the output.

(Object of the Invention) In view of the above circumstances, the present invention provides an engine intake device that can improve combustion efficiency in low and medium load ranges without reducing output in high load ranges during high-altitude operation. It is something to do.

(Structure of the Invention) The present invention comprises an intake passage downstream of the throttle valve consisting of a low-load intake passage and a high-load intake passage, and the high-load intake passage is provided with a control valve that closes at low load, and In an engine intake system equipped with a control means for controlling the opening degree of the 1III1 valve according to the operating state, the engine intake system includes a high-altitude operation detecting means for detecting high-altitude operation, and a high-altitude operation detecting means for detecting high-altitude operation. The control valve is provided with a correction means that corrects the opening degree of the control valve in the opening direction and reduces the amount of correction as the engine load increases.

In other words, when driving at high altitudes, tJl is naturally
I noticed that valve 69 tends to open more than the proper opening.

Combustion efficiency is increased by correcting the opening of the control valve in the closing direction to the extent that the opening of the control valve is corrected, and an increase in intake resistance is prevented by reducing the amount of correction of the opening of the control valve in the high load range. There is.

(Embodiment) FIG. 1 shows an embodiment of the overall structure of the device of the present invention. In this figure, in an intake passage 3 that supplies intake air to a combustion chamber 2 formed in a cylinder 1 of an engine, a high-load intake passage 5 and a low-load intake passage 6 are formed downstream of a throttle valve 4. The downstream end of the intake passage 3 opens into the combustion chamber 2, and the opening 7 is equipped with an intake valve 8. The high-load intake passage 5 is formed with a relatively large passage area and communicates with the opening 7, and an llll1l valve 9 made of a spiral valve or the like is interposed in the high-load intake passage 5. ing. Furthermore, the low-load intake passage 6 has a smaller passage area than the high-load intake passage 5, and is formed along and below the high-load intake passage 5, and is located upstream of the high-load intake passage 9. It branches from the high-load intake passage 5, and its downstream end opens into the high-load intake passage 5 immediately upstream of the intake valve 8.

The downstream end of the low-load intake passage 6 opens in the tangential direction of the cylinder 1, and the intake air passing through the low-load intake passage 6 is supplied to the combustion chamber 2 in the circumferential direction. on the other hand,
The vicinity of the downstream end of the high-load intake passage 5 is bent or curved so as to open in the axial direction of the cylinder 1 with respect to the intake passage 3 . Therefore, when the control valve 9 is closed, the high-load intake passage 5 is blocked by the control valve 9, and the low-load intake passage 6 is closed.
By supplying intake air to the combustion chamber 2 from the combustion chamber 2, the intake flow velocity is increased and a strong intake swirl is generated within the combustion chamber 2. When the control valve 9 is opened, intake air is supplied from the high-load intake passage 5. This reduces intake resistance and suppresses intake swirl. The structure is such that the intake flow rate, intake resistance, and strength of the intake swirl are adjusted according to the opening degree of the 11611 valve 9.

The III ml valve 9 is opened to the minimum opening degree in the low load area near idling operation, and is fully opened to approximately t in the high load area,
It is controlled by a control unit 11 made up of a microcomputer or the like via an actuator 10 made of a linear solenoid or the like so that the opening degree changes depending on the operating state. The control unit 11 includes a negative pressure sensor 12 that detects intake negative pressure downstream of the throttle valve 4, a rotation speed sensor 13 that detects the engine speed, and a throttle opening sensor 14 that detects the opening of the throttle valve 4. and an atmospheric pressure sensor 15 that detects atmospheric pressure.
Each detection signal from and is input.

The negative pressure sensor 12 and the rotation speed sensor 13 are for detecting the operating state, and the atmospheric pressure sensor 1
5 is a high-altitude driving detection means for detecting when the vehicle is driving at high altitudes.

The control unit 11 includes a memory 16 and a CP
The memory 16 has an IIJ control section 17 consisting of U, etc.
As shown in FIG. 3, the target opening degree φ of the control valve 9 is stored in advance as a map that corresponds to the intake negative pressure Pb and the engine speed N, and the correction amount for high-altitude driving, which will be described later, is also stored. has been done. Further, the control section 17 includes 1I
It has a function as a control means for controlling the opening degree of the JIL valve 9 according to the operating state, and a function as a correction means for correcting the opening degree of the control valve 9 during high-altitude operation. It is designed to perform calculations and control.

FIG. 2 is a flowchart showing a specific example of control by the control section 17. This 70-chillate starts when the engine is started, and first, in step $1, the intake negative pressure Pb and the engine speed N are read. Next, in step S2, a value f (N, Pb) read from the map in FIG. 3 according to the actual intake negative pressure Pb and engine speed N.
is set as the target opening degree φ. Subsequently, in steps S3 and S4, it is determined whether the atmospheric pressure Pa detected by the atmospheric pressure sensor 15 is smaller than a reference value Pao serving as a high-altitude driving determination level. Then, during lowland driving where the atmospheric pressure Pa is equal to or higher than the reference value Pao, in step S5,
After setting the correction amount Δφ of the control valve opening degree to 0, which will be described later, the process moves to step S9, which will be described later.

During high-altitude operation when the atmospheric pressure pa is lower than the reference value Pao, a correction amount Δφ of the control valve opening during high-altitude operation is calculated in steps 88 to S8.

That is, the opening degree θ of the throttle valve 4 detected by the throttle opening degree sensor 14 is read, a correction value Δφ0 which is a value f(θ) corresponding to this opening degree θ is determined, and the above correction value Δφ0 is added to the correction value Δφ0. Correction coefficient f'' (pao-Pa) according to the difference between the reference value pao and the detected atmospheric pressure pa
The correction amount Δφ of the control valve opening degree during high-altitude operation is determined by multiplying by Δφ. In this case, the correction value Δφ0 is made smaller as the opening degree of the throttle valve 4 becomes larger, as shown in FIG. 4, and the relationship between the correction amount Δφ and the atmospheric pressure pa is as shown in FIG. , the correction amount Δφ increases as the atmospheric pressure decreases, and the correction value Δφ0 and correction coefficient f−(P
ao-Pa) may be stored in the memory 16 in advance and read out from there.

Next, in step S9, the final target opening degree φ is obtained by subtracting the correction amount Δφ from the target opening degree φ according to the driving state, that is, when driving at high altitudes, the correction amount Δ
The target opening degree φ is decreased by φ, and then in step S1o, the control valve 9 is operated so that the target opening degree φ is achieved.

By controlling the opening degree of the IIJw valve 9 according to the above flowchart, the intake air supply state is appropriately adjusted. In other words, as mentioned above, the basic control is to reduce the opening of the control valve 9 at low loads to increase intake flow velocity and intake swirl, and at high loads to increase the opening of the control valve 9 to reduce intake resistance. Reduced. In addition, especially when driving at high altitudes, the density of the intake air decreases, so the throttle valve 4 tends to open more than when driving at low altitudes, and the apparent load increases. With similar control, the relationship of the control valve 9 tends to become too large and the combustion rate decreases, especially in the low and medium load ranges. Therefore, during high-altitude operation, the opening of the control valve 9 is closed to compensate for the above tendency. direction is corrected to prevent a decrease in combustion efficiency. Furthermore, even during high-altitude operation, the amount of correction of the opening degree of the control valve 9 is reduced when the load is high, thereby avoiding an increase in intake resistance during the high load.

Note that the present invention is not limited to an engine in which the downstream end of the low-load intake passage 6 opens into the high-load intake passage 5 immediately upstream of the intake valve 8 as in the above embodiment, but is applicable to low-load and high-load applications. Both load intake passages open independently into the combustion chamber,
It can also be applied to an engine in which each opening is equipped with an intake valve.

(Effects of the Invention) As described above, the present invention adjusts the intake flow velocity, intake swirl, etc. to suit the operating conditions by controlling the opening degree of the control valve provided in the high-load intake passage. During operation, the relationship of the liI control valve is corrected in the closing direction, and the amount of correction is made smaller as the load increases.
When driving at high altitudes, it is possible to improve fuel efficiency and output by increasing combustion efficiency in low and medium load areas, where combustion efficiency is naturally more likely to decrease than at low altitudes, while avoiding a decrease in output in high load areas. be.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing one embodiment of the overall structure of the device of the present invention, Fig. 2 is a control flowchart, Fig. 3 is an explanatory diagram of the target opening degree stored in the memory, Figs. 4 and 5 FIG. 2 is an explanatory diagram showing the relationship between the throttle opening degree and a correction value during high-altitude driving, and the relationship between atmospheric pressure and correction a. 3... Intake passage, 4... Throttle valve, 5... Intake passage for high load, 6... Intake passage for low load, 9...
Control valve, 11... Control unit, 14...
Throttle opening sensor, 15... Atmospheric pressure sensor, (high altitude driving detection means). Patent applicant Mazda Co., Ltd. Agent
Patent Attorney Etsushi Kotani Patent Attorney
1) Masamukai Patent Attorney Yasuo Itaya Figure 1 Figure 2

Claims (1)

[Claims] 1. The intake passage downstream of the throttle valve is composed of a low-load intake passage and a high-load intake passage, and the high-load intake passage is provided with a control valve that closes at low load, and the opening degree of this control valve is controlled. In an engine intake system that is equipped with a control means that controls according to the operating state, there is a high-altitude operation detection means that detects high-altitude operation, and receives the output of this detection means and controls the opening degree of the control valve in the closing direction during high-altitude operation. What is claimed is: 1. An intake system for an engine, characterized in that it is provided with a correction means that corrects the amount of correction and reduces the amount of correction as the load of the engine becomes higher.