JPH0443826A - Intake control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain high power for work by making opening control of an intake control valve through a valve opening adjusting means effective at no detection of a work mode detecting means, and making opening control of an intake control valve through a valve opening adjusting means ineffective at detection of a work mode. CONSTITUTION:At usual running, as a lift lever is not operated, a switch 19 is OFF, an atmospheric port 11b is opened and a negative pressure port 11c is closed with the slide valve 15 of a solenoid valve 11. Hereby, the atmospheric pressure is applied to the atmospheric chamber 6b of an actuator 5, and pressure difference between the atmospheric pressure and negative pressure applied to a negative pressure chamber 6a is actuated on a piston 7. Meanwhile, at cargo handling of a fork lift, the lift lever is operated, the switch 19 is ON, the port 11b is closed and the port 11c is opened with the slide valve 15 of the solenoid valve 11, and negative pressure is applied to the atmospheric chamber 6b. In this condition, the piston 7 is pulled on the atmospheric chamber 6b side by the resultant force of tension of the governor spring of the actuator 5 and the negative pressure applied to the chamber 6b, and an intake control valve 4 is forcedly opened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an intake control device for controlling the rotational speed of an internal combustion engine.

[Prior Art] Conventionally, as this type of intake control device, for example,
A technique disclosed in Japanese Patent No. 24284 is known.

In this technology, an intake control valve is installed separately from the throttle valve installed in the intake passage of the internal combustion engine, and controls the maximum rotational speed of the internal combustion engine at a constant level by changing the effective flow area of the intake passage. It was equipped with an air governor. The opening degree of the intake control valve is set in advance according to the required output when the vehicle is running, and the maximum rotation speed is prevented from increasing too much.

[Problems to be Solved by the Invention] However, in the case of the conventional example described above, an excessive increase in the maximum rotational speed was suppressed by setting the opening degree of the intake control valve. When applied, it was only possible to respond to a certain amount of output for the difference in required output between normal driving and cargo handling for forklifts.

Therefore, if the opening of the intake control valve is set to obtain the maximum rotation speed based on the required output during cargo handling, the maximum rotation speed will exceed the required output during driving, and the speed will increase. Not only was there a risk of excessive noise, but there was also a risk of worsening running noise and fuel efficiency. For this reason, the driver had to be careful when operating the accelerator, which caused problems in terms of driving operability.

On the other hand, if the opening of the intake control valve is set to obtain the maximum rotation speed based on the required output during normal driving, the maximum rotation speed will be lower than the required output during cargo handling, and the There was a risk that this would lead to a lack of output.

This invention was made in view of the above-mentioned circumstances, and its purpose is to make it possible to obtain driving output at the highest rotational speed commensurate with the required output during normal driving, and to make it possible to obtain driving output at the highest rotational speed commensurate with the required output. An object of the present invention is to provide an intake air control device for an internal combustion engine that can secure a necessary maximum rotational speed when in a mode and obtain high output for work.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a throttle valve that is provided separately from a throttle valve provided in an intake passage of an internal combustion engine, and that is capable of varying the effective flow area of the intake passage. and a valve opening that adjusts the opening of the intake control valve according to the amount of intake air in the intake passage in order to control the internal combustion engine to a preset maximum rotation speed in accordance with the required output during normal driving. In the intake control device for an internal combustion engine, the intake control device for an internal combustion engine includes a work mode detection means for detecting a work mode other than normal driving, and when the work mode detection means does not detect a work mode, the intake control valve is opened by the valve opening adjustment means. and a switching means for disabling the opening adjustment of the intake control valve by the valve opening adjustment means and opening the intake control valve when the work mode detection means detects the operation mode.

[Function] According to the above configuration, when the work mode detection means does not detect the operation mode during normal driving, the switching means enables the opening adjustment of the intake control valve by the valve opening adjustment means. Therefore, even if the throttle valve is fully open, the valve opening adjustment means adjusts the opening of the intake control valve according to the amount of intake air in the intake passage, and the internal combustion engine is set in advance according to the required output during normal running. The maximum rotation speed is controlled. In other words, the maximum rotational speed is prevented from increasing too much.

Also, when detecting a work mode other than normal driving,
The switching means disables the opening adjustment of the intake control valve by the valve opening adjustment means, and the intake control valve is opened. Therefore, when the throttle valve is fully opened, the maximum rotational speed of the internal combustion engine is increased higher than the maximum rotational speed during normal running.

[Example] Hereinafter, an example in which the present invention is embodied in a forklift will be described in detail based on the drawings.

FIGS. 1 and 2 are diagrams illustrating the schematic structure and operation of the intake air control device for a forklift engine in this embodiment. A venturi 2 is provided in the intake passage 1, and a throttle valve 3 that is opened and closed in conjunction with the operation of an accelerator pedal (not shown) is provided downstream of the venturi 2. Furthermore, on the downstream side of the slot-sottle valve 3, there is provided an intake control valve 4 which is provided separately from the opening valve 3 and which makes the effective flow area of the intake passage 1 variable.

The intake control valve 4 controls the engine to a preset maximum rotation speed according to the required output during normal driving, and prevents the maximum rotation speed from increasing too much.
An air cabana is constituted by an actuator 5 as a valve opening adjustment means for adjusting the opening of the intake control valve 4 according to the amount of intake air. A piston 7 is provided in the cylinder 6 of the actuator 5 so as to be able to reciprocate. This piston 7 is connected to one end of the intake control valve 4 via a link 9 that extends through a through hole 8 . Further, a valve shaft 4a, which is the center of rotation of the intake control valve 4, is provided eccentrically, and a guard spring and a governor spring (not shown) are attached to the valve shaft 4a.

Then, the governor spring controls the intake control valve 4 from the first
It is biased to rotate clockwise in Figure 2.

Further, the negative pressure of the intake passage 1 acts on the negative pressure chamber 6a on one side of the cylinder 6 divided by the piston 7 through the through hole 8, and one end of the communication pipe 10 is connected to the atmospheric chamber 6b on the other side. ing. The other end of the communication pipe 10 is connected to a communication port lla of a solenoid valve 11 as a switching means.

The solenoid valve 11 has an atmospheric port 11b in addition to the communication port 11a.
and a negative pressure port Ilc. One end of an atmospheric pipe line 12 communicating with the outside is connected to the atmospheric port llb, and one end of a negative pressure pipe line 13 communicating with the intake passage 1 downstream of the intake control valve 4 is connected to the negative pressure port lie. has been done. Further, in order to perform port switching, the solenoid valve 11 is provided with a slide valve 15 that is opened and closed by energizing (ON) and de-energizing (OFF) the electromagnetic coil 14.

When the electromagnetic coil 14 is de-energized, the slide valve 1
As shown in FIG. 1, 5 is placed in a position where a spring 16 closes the negative pressure port ILc and opens the atmospheric port Ilb, thereby allowing the communication port 11a and the atmospheric port Ilb to communicate with each other. In other words, the atmospheric chamber 6b of the actuator 5
Apply atmospheric pressure to In this state, a pressure difference between the atmospheric pressure acting on the atmospheric chamber 6b and the negative pressure acting on the negative pressure chamber 6a of the actuator 5 through the through hole 8 acts on the piston 7. Further, a force that tends to close the opposite valve 4 acts on the eccentric intake control valve 4 due to the intake air flow.

Therefore, the pressure difference acting on the piston 7 plus the force acting to close the eccentric intake control valve 4 is balanced with the tension of the governor spring, and the opening degree of the intake control valve 40 is maintained at an appropriate level. It will be done.

On the other hand, when the electromagnetic coil 14 is energized, the slide valve 15 is placed in a position to open the negative pressure port 11c against the spring 16 and close the atmospheric port 11b, as shown in FIG. Communicate with port llc. That is, the negative pressure generated in the negative pressure pipe line 13 is applied to the atmospheric chamber 6b of the actuator 5. In this state, the resultant force of the tension of the governor spring of the actuator 5 and the negative pressure acting on the atmospheric chamber 6b becomes greater than the negative pressure acting on the negative pressure chamber 6a, and the piston 7 is pulled toward the atmospheric chamber 6b to control the intake air. Valve 4 is forced open.

A battery 18 is provided in the power supply circuit 17 of the solenoid valve 11, and its positive side is connected to the positive side of the electromagnetic coil 14, and its negative side is connected to the negative side of the electromagnetic coil 14 via a limit switch 19 as a work mode detection means. has been done. In this embodiment, the limit switch 19 is a switch that is turned on and off in conjunction with a lift lever (not shown) of the forklift. When the lift lever is not operated, that is, when the vehicle is running normally, the limit switch 19 is turned off as shown in FIG. 1, cutting off the power to the electromagnetic coil 14. Further, when the lift lever is operated, that is, when lifting the fork for cargo handling, the limit switch 19 is turned on as shown in FIG. 2, and the electromagnetic coil 14 is energized.

Next, the operation of the intake control device for an internal combustion engine configured as described above will be explained.

Now, when the forklift is running normally, the lift lever is not operated, so the limit switch I9 is in the OFF state as shown in Fig. 1, and the slide valve 15 of the solenoid valve 11 opens the atmospheric port 1 lb. It is arranged in a position to close the negative pressure port llc together with the negative pressure port llc. Therefore, atmospheric pressure acts on the atmospheric chamber 6b of the actuator 5,
The pressure difference between the atmospheric pressure and the negative pressure acting on the negative pressure chamber 6a acts on the piston 7. Therefore, the pressure difference acting on the piston 7 plus the force acting to close the eccentric intake control valve 4 balances the tension of the governor spring and maintains the opening of the intake control valve 4 at an appropriate level. It will be done. In other words, the normal operation as an air governor is performed, the engine is controlled to the maximum rotational speed commensurate with the required output during normal driving, and the driving output is moderately suppressed.

Therefore, even if the accelerator pedal is depressed deeply and the throttle valve 3 is fully opened, the intake air amount is suppressed by the intake control well 4, so that the maximum engine speed will not increase more than necessary. In addition, the maximum rotation speed setting at this time is
It can be changed as appropriate by adjusting the biasing force of the governor spring.

On the other hand, when the forklift is handling cargo, the lift lever is operated, so the limit switch 19 is turned on as shown in FIG.
is placed in a position where it closes the atmospheric port llb and opens the negative pressure port 11c. This causes negative pressure to act on the atmospheric chamber 6b of the actuator 5. In this state, the piston 7 is pulled toward the atmospheric chamber 6b by the combined force of the tension of the governor spring of the actuator 5 and the negative pressure acting on the atmospheric chamber 6b, and the intake control valve 4 is forcibly opened.

Therefore, the more the throttle valve 3 is opened in response to depression of the accelerator pedal, the more the intake air amount in the intake passage 1 increases and the engine speed increases. Therefore, the maximum rotation speed during cargo handling is increased compared to that during normal driving,
It is possible to increase engine output during cargo handling. In other words,
It is possible to obtain the required output during cargo handling.

As described above, in this embodiment, during normal driving, the engine is controlled to the maximum rotational speed commensurate with the required output, and it is possible to obtain an appropriate driving output that does not exceed the required output. This not only prevents you from driving too fast and makes it easier to operate the accelerator, but also reduces the load on the engine and reduces driving noise. Fuel efficiency can be improved.

On the other hand, during cargo handling, it is possible to secure the maximum rotational speed necessary for cargo handling and obtain cargo handling output commensurate with the required output. In other words, the maximum engine speed can be increased only during cargo handling.

Note that this invention is not limited to the above embodiments,
The present invention can be implemented as follows by changing a part of the structure as appropriate without departing from the spirit of the invention.

(1) In the above embodiment, the electric limit switch 19 linked to the lift lever was provided as a work mode detection means to switch the port of the solenoid valve 11 as a switching means. It may be configured to be an interlocking mechanical member and to switch ports of a three-way valve as a switching means.

(2) In the above embodiment, a forklift is used that performs cargo handling using forks as a work mode in addition to normal driving, but the work mode may be any mode that requires high engine output in addition to cargo handling using forks. .

[Effects of the Invention] As detailed above, according to the present invention, when the work mode detection means for detecting a work mode other than normal driving is not detected, the opening degree adjustment of the intake control valve by the valve opening degree adjustment means is effective. and when the work mode detection means detects the intake control valve, the opening adjustment of the intake control valve by the valve opening adjustment means is disabled and the intake control valve is opened, so that the maximum rotational speed corresponding to the required output is maintained during normal driving. This provides an excellent effect in that it is possible to obtain power for running, and at the same time, when in a work mode other than normal driving, it is possible to secure the required maximum rotational speed and obtain high power for work.

[Brief explanation of drawings]

FIGS. 1 and 2 are diagrams illustrating the schematic structure and operation of an air intake control device for a forklift engine in an embodiment embodying the present invention. In the figure, 1 is an intake passage, 3 is a throttle valve, 4 is an intake control valve, 5 is an actuator as a valve opening adjustment means, 11
19 is a solenoid valve as a switching means, and a limit switch 19 is a work mode detection means.

Claims (1)

[Scope of Claims] 1. An intake control valve that is provided separately from a throttle valve provided in an intake passage of an internal combustion engine and that makes the effective flow area of the intake passage variable; and a requirement for normal running of the internal combustion engine. An intake control device for an internal combustion engine, comprising: valve opening adjustment means for adjusting the opening of the intake control valve according to the amount of intake air in the intake passage in order to control the rotation speed to a preset maximum rotation speed according to the output. a work mode detection means for detecting a work mode other than normal driving; and when the work mode detection means does not detect, the work mode detection means enables adjustment of the opening of the intake control valve by the valve opening adjustment means; An intake control device for an internal combustion engine, comprising a switching means that disables the opening adjustment of the intake control valve by the valve opening adjustment means and opens the intake control valve when detecting the above.