JPH06101503A - Suction gas throttle method for methanol engine - Google Patents

Abstract

PURPOSE:To make fine and accurate control of the degrees of valve opening by adjusting the opening of a suction valve in connection with the suction side of an engine using a stepping motor in conformity to a plurality of signals, and not admitting motor revolution control when the conditions require such. CONSTITUTION:A methanol engine 2 of diesel type undergoes a suction throttle control in such a way that the opening of a suction valve 1 in connection with the suction side is adjusted. A stepping motor 11 is connected with the suction valve 1, and the degree of opening is made adjustable. The stepping motor 11 undergoes revolution control made by a control unit 5 in conformity to a plurality of signals at least including the exhaust temp. of an exhaust pipe 4 and the cooling water temp. in the engine 2. This revolution control is not admitted when the engine 2 operates idling and when an exhaust brake 3 is in application. When either of the exhaust temp. and cooling water temp. lies below the specified level, no revolution control takes place, and the suction valve 1 is maintained in shut state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake throttle method applied to a methanol engine, and more particularly to a diesel type intake throttle method for a methanol engine.

[0002]

2. Description of the Related Art In a diesel type methanol engine, the cetane number of methanol or a mixed oil of methanol, which is to be used as a fuel, is lower than that of light oil. Therefore, in order to perform ignition combustion using a spark plug like a gasoline engine. , It is known that the fuel consumption is improved and combustion is stabilized by optimizing the intake air amount with the intake valve.

As an intake valve control method of this type, a three-position actuator connected to the intake valve is used, and the valve opening is fully closed during low speed and low load such as idling or during exhaust brake operation, and during medium speed and medium load. Three-step control is performed so that the valve opening is half closed and fully opened at high speed and high load.

[0004]

However, as described above, the three-step control cannot perform fine control, and in particular, since the vehicle speed and the load are not necessarily in a correspondence relationship, it is possible to cope with, for example, low speed high load high speed low load. Can not. Further, in the above-mentioned conventional technique, the exhaust brake is fully closed when it is operated. However, if such a control is performed, not only the brake efficiency becomes poor, but also the engine may misfire.

In order to solve such a drawback, there is a structure in which the accelerator pedal and the intake valve are connected via a wire, and the opening degree of the intake valve is controlled according to the opening degree of the accelerator pedal. , Controlling only the accelerator opening does not lead to efficient fuel efficiency improvement and stable combustion, but especially in the case of a methanol engine, formaldehyde is easily exhausted until the engine is warmed up. Even if not, at the stage of shifting to medium speed or high speed operation,
The intake valve is opened and formaldehyde cannot be prevented from being exhausted.

In view of the above-mentioned drawbacks of the prior art, the present invention is an intake air for a methanol engine capable of accurately and precisely controlling the valve opening degree of the intake valve in response to a plurality of input signals having an influence on the improvement of fuel consumption and combustion stability. The purpose is to provide a diaphragm method. Another object of the present invention is to provide an intake throttling method for a methanol engine capable of controlling the valve opening while smoothly reducing the generation of formaldehyde. Another object of the present invention is to provide an intake throttle method for a methanol engine capable of controlling the valve opening degree of an intake valve without deteriorating the braking efficiency or causing engine misfire even when an exhaust brake is operated. The purpose is to provide.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an intake throttle method in which an intake valve is connected to the intake side of a diesel type methanol engine and the intake throttle control is performed by adjusting the opening of the intake valve. The first feature is that a stepping motor is connected to the intake valve,
The point is that the opening degree can be adjusted by the stepping motor. That is, since the stepping motor is used instead of the actuator, it is possible to precisely adjust the opening degree.

The second feature is that the rotation control of the stepping motor is controlled by a plurality of signals obtained from the engine side and the exhaust side.
More specifically, the load of engine speed, shaft torque, etc.
A characteristic is that a basic three-dimensional map of the intake valve opening is formed based on one of the functions, and the rotation control is performed by adding a correction coefficient for the engine cooling water and the exhaust temperature to the three-dimensional map. And With this, like the conventional technology,
Since it is not controlled by one input signal of accelerator opening or vehicle speed, it is basically controlled by a three-dimensional map based on two input signals of engine speed and load. Not only three-step control of load and high-speed / high-load, but also precise control is possible even in the case of low-speed / high-load and low-speed / high-load.

When the valve is opened before the engine is warmed up as in idling, formaldehyde is generated in the rotation control, which is a pollution problem. Therefore, the third feature of the present invention is that the intake valve is fully closed without allowing the rotation control during idling. This can accelerate the warming of the engine and effectively reduce the generation of formaldehyde during idling.

Further, according to a fourth feature of the present invention, when an exhaust brake operation ON signal is input during the control of the opening degree of the intake valve during normal traveling, the ON signal is prioritized and an interrupt is inserted. . This makes it possible to set the opening corresponding to the exhaust brake irrespective of the valve opening conditions during normal running. For example, by setting the valve to about half open, the braking efficiency does not deteriorate and the engine misfires. It is possible to set the most appropriate opening without fear of causing it.

In order to reduce the emission of formaldehyde, it is preferable to close the engine when the engine is warmed up, instead of closing it only during idling. Therefore, claim 2
In the invention described above, the plurality of signals include an exhaust temperature and an engine cooling water temperature, and when either the exhaust temperature or the cooling water temperature is equal to or lower than a predetermined temperature, the intake valve is turned on without performing the rotation control. I try to keep it closed. That is, at the time of cold start, the intake valve is fully closed until the exhaust gas temperature reaches the set temperature, and when the cooling water temperature is 50 ° C or less even during normal running, it is fully closed, or between 50 ° C and 60 ° C. Is multiplied by a correction coefficient between 0 and 1, and the opening degree is adjusted in accordance with the correction coefficient. Further, when the temperature is 60 ° C. or higher, the opening degree is adjusted only by the rotation speed and the load. As a result, formaldehyde can be smoothly reduced without impairing fuel economy and combustion stability.

[0012]

Embodiments of the present invention will now be illustratively described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative positions and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely examples, unless otherwise specified. Not too much. Figure 1
1 is an intake / exhaust system diagram of a diesel-type methanol engine according to an embodiment of the present invention. Reference numeral 1 is an intake valve, and a rotation shaft thereof is connected to a step motor 11 with a position sensor. The step motor 11 is configured to be rotatable by a predetermined angle based on an output signal from the control unit 5. Reference numeral 2 denotes a diesel-type methanol engine, which sends control signals corresponding to the engine speed obtained from a sensor (not shown), an engine load obtained from a fuel injection pump rack sensor, and a cooling water temperature to the control unit 5 side. It is configured to be possible.
Reference numeral 3 is an exhaust brake, and the ON / OFF switch 3a signal thereof can be sent to the control unit 5 side. An exhaust pipe 4 is provided with a temperature sensor (not shown) immediately after passing through the exhaust gas purifying catalyst, and the exhaust temperature obtained from the sensor can be sent to the control unit 5 side. The control unit 5, together with the signal,
Input the idle-up signal, etc. obtained from the opening degree of the actuator of the fuel injection pump of the engine.

Next, the operation of this embodiment will be described with reference to FIGS. First, after the start key is turned on in the parking or neutral state, in the case of low temperature starting, if the exhaust gas temperature that may generate formaldehyde is H _T, and if the exhaust gas temperature is H _T or less, the correction coefficient H is set to The value is set to 0 and the intake valve is set to be closed regardless of the rotational speed R and the load F. (See FIG. 3 (2)) (STEP 1) Then, even when the exhaust temperature becomes H _T or higher, the intake valve 1 is maintained in the fully closed state without performing rotation control in the idling state. . (STEP2) As a result, it is possible to effectively warm up the engine and effectively reduce the generation of formaldehyde during idling.

Then, in the above-mentioned state, the engine injection pump is slightly opened, and when the idle-up is performed, the rotation control routine is started. (STEP3) Then, the rotation control routine is controlled based on the following equation. B ₁ = H {w (R, F)} B ₂ = T or B ₂ = H {w (T)} B ₁ : Intake valve opening during normal running B ₂ : At idle up (for example, 800 to 900 rpm) Basically, the intake valve 1 is opened by a small valve opening T (about 0.2 to 1 mm when the valve diameter is 80 mm) regardless of the rotational speed R and the load F. H: Exhaust temperature correction coefficient. That exhaust temperature that may formaldehyde is generated if an H _T, the when the exhaust gas temperature is below H _T, the correction coefficient H is zero also the exhaust temperature H _T or more of the correction factor if H Is set to 1. W: Correction coefficient for cooling water temperature. When the temperature of the cooling water is 50 ° C or less, the correction coefficient is set to 0, and between 50 ° C and 60 ° C, 0 to 1 corresponding to the temperature.
If the temperature is 60 ° C. or higher, the correction coefficient between 1 and 2 is set to 1.

According to this embodiment, at the time of idling, the engine is rotated with the valve opening T of the intake valve being slightly opened so that the engine does not misfire, and then the vehicle is shifted to normal running by a gear change. In this case, when the exhaust gas temperature is equal to or higher than H _T , the correction coefficient H is set to 1 and the opening degree is adjusted according to the relationship between the rotation speed R and the load F. The engine operation is performed while adjusting the opening degree of the intake valve 1 based on the angle determined by the relationship with F. (Refer to FIG. 3 (1) and the opening degree map of FIG. 4) (STEP 3) As a result, precise and accurate opening degree control can be performed based on two factors (low to high load) (low speed to high speed). In addition to being able to do so, it can accelerate the warming of the engine and prevent the generation of unnecessary formaldehyde.

In this case, when the cooling water temperature is 50 ° C. or lower at the beginning of normal running, the engine is fully closed to promote warming of the engine, and between 50 ° C. and 60 ° C., a correction coefficient of 0 to 1 is applied. , Engine warm-up promotion and misfire prevention are performed, and the opening degree is adjusted in accordance with the correction coefficient.
If the temperature is above ℃, adjust the opening only by the rotation speed and load. As a result, formaldehyde can be smoothly reduced without impairing fuel economy and combustion stability.

Further, during the normal traveling, the intake valve 1
When the exhaust brake operation ON signal is input during the opening control of (No. 4) (STEP 4), the ON signal is prioritized to generate an interrupt, and the opening corresponding to the exhaust brake is irrelevant regardless of the valve opening condition during normal traveling. By setting, for example, about half-opening of the valve, there is no fear that the braking efficiency will deteriorate and the engine will not misfire. (See Figure 3 (3))

[0018]

As described above, according to the present invention, the valve opening degree of the intake valve can be accurately and precisely controlled in response to a plurality of input signals that have an influence on fuel efficiency improvement and combustion stability. Further, according to the present invention, it is possible to control the valve opening while smoothly reducing the generation of formaldehyde, which is a drawback when a methanol engine is used. Further, according to the present invention, even when the exhaust brake is operated, the valve opening degree of the intake valve can be controlled without deteriorating the braking efficiency or causing the engine to misfire. It has various remarkable effects.

[Brief description of drawings]

FIG. 1 is an intake / exhaust system diagram of a diesel-type methanol engine according to an embodiment of the present invention.

FIG. 2 is a flow chart showing the intake throttle method of FIG.

FIG. 3 shows various aspects of an intake throttle method.

FIG. 4 is a three-dimensional map showing rotation speed, load, and opening of an intake valve.

[Explanation of symbols]

 1 intake valve 11 step motor with position sensor 2 diesel type methanol engine 3 exhaust brake 4 exhaust pipe 5 control unit

Claims (2)

[Claims] 1. An intake throttle method in which an intake valve is connected to an intake side of a diesel type methanol engine, and an intake throttle control is performed by adjusting an opening of the intake valve, wherein a stepping motor is connected to the intake valve. , The opening is adjustable by the stepping motor,
An intake air for a methanol engine, characterized in that the rotation control of the stepping motor is performed based on a plurality of signals obtained from the engine side and the exhaust side, and the rotation control is not allowed at the time of idling and the operation of the exhaust brake. Aperture method 2. The exhaust signal and the engine cooling water temperature are included in the plurality of signals, and when either the exhaust temperature or the cooling water temperature is equal to or lower than a predetermined temperature, the intake valve is operated without performing the rotation control. The intake throttle method for a methanol engine according to claim 1, characterized in that the intake throttle method is maintained closed.