JPH03264756A - Intake control device of engine for motorcycle - Google Patents

Abstract

PURPOSE:To perform fine control of air-fuel ratio by open/close controlling a solenoid valve, provided in each air passage of main and pilot systems, through a throttle opening and an engine speed to prevent richness of a mixture especially in intermediate and low speed regions. CONSTITUTION:A main system air passage 10 is opened to an air bleed 9 of a main jet 8, actuated by a negative pressure of an engine 3, in the lower part of an intake passage 7 in a carburetor 5, and a pilot system air passage 11 is opened to the lower part of the intake passage 7 in the downstream side from this passage 10. An air passage 13 for supplying air from an air cleaner 12 is branched halfway, and a correcting air passage is formed by connecting each branch passage 14, 15 to halfway the air passages 10, 11. A duty solenoid valve 16 and an on-off solenoid valve 17 are connected respectively to the branch passages 14, 15, and each solenoid valve 16, 17 is open/close controlled by a control unit 20 being based on outputs of a throttle opening sensor 18 and an engine speed sensor 19.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an air intake control device for a motorcycle engine.

(Prior Art) Conventionally, there is a system for supplying air to a carburetor of an engine for a two-wheeled motor vehicle, as shown in FIG. 10.

This system includes two air passages f and g as an air supply system to an air passage e which has an air jet d that supplies air to the air bleed C of the main jet b of the carburetor a.
are arranged in parallel, and solenoid valves h and i are connected to these air passages f and g, so that the amount of air supplied is controlled by the combination of opening and closing of the solenoid valves h and i that pass through the air filter j. be. When both solenoid valves h and i are closed, one solenoid valve h is open and the other solenoid valve j is closed, one solenoid valve h is closed and the other solenoid valve is closed. Control is performed in four ways: when only one solenoid valve h and i are open, and when both solenoid valves h and i are both open.

(Problem to be Solved by the Invention) However, according to the conventional intake control device for motorcycle engines, the amount of air in the main system is adjusted within the range of the ON/OFF combination of two solenoid valves. Therefore, it simply adjusts the amount of air in the main system in stages, and therefore it is only possible to make fine adjustments to the air-fuel ratio in the low and medium speed ranges, especially when the In the partial range, the mixture may become too rich at low speeds, and at high speeds it may become too lean, and at full throttle, the mixture may become too rich at low speeds or at high speeds. It is inevitable that this will occur. Therefore, the entire rotation range,
In particular, it was difficult to precisely control the air-fuel ratio in the low and mid-speed range.

In view of the above points, this invention enables fine control of the appropriate air-fuel ratio required by the engine over the entire rotation range of the engine, and also deals with optimizing the air-fuel ratio when starting at low temperatures and starting at high places. The present invention provides an air intake control device for an engine for a two-wheeled motor vehicle that makes it possible to do this.

C Structure of the Invention] (Means for Solving the Problems) As a means for solving the problems of the above-mentioned prior art, the present invention provides two channels that connect the air passage from the air filter to the main system and pilot system of the carburetor. Branches into an air passage,
Solenoid valves are connected to the air passages connected to the main system and the pilot system, and these solenoid valves are opened and closed by a control unit operated by the throttle opening and engine speed.

In addition, as described in claim 2, in order to prevent the air-fuel ratio from becoming diluted at the time of cold start, the control unit controls the opening degree of the solenoid valve based on the detection result of the temperature sensor. As described above, in order to further prevent an excessive concentration of the air-fuel ratio when starting at a high altitude, the control unit controls the opening degree of the solenoid valve based on the detection result of the atmospheric pressure sensor.

(Function) Air passages are connected to the main system and pilot system of the carburetor, and the amount of air supplied through these air passages is controlled by a solenoid valve that is opened and closed by a control unit to which the throttle opening and engine speed are input. .

This controls the air-fuel ratio at low and medium speeds,
This prevents the air-fuel mixture from becoming over-enriched or diluted, making it possible to precisely supply the air-fuel mixture with the appropriate air-fuel ratio required by the engine.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows an embodiment in which the air intake control device of the present invention is mounted on a motorcycle 1, in which an engine 3 is mounted at the lower center of a body frame 2.
A carburetor 5 and an air cleaner that constitute an engine intake system are provided on the rear side of the cylinder 4. The rotation of the engine 3 is transmitted to the rear wheels 6 by a transmission mechanism (not shown).

FIG. 1 shows an example of a system 1 of an intake air control device for a motorcycle engine according to the present invention. The carburetor 5 has a main jet 8 operated by the negative pressure of the engine 3 at the lower part of the intake passage 7, and the main system air passage 0 is opened in the air vent 9 of the main jet 8, and the intake passage downstream from this is opened. Pilot system air passage 1 at the bottom of 7
1 is open.

The air passage 13 that supplies air from the air cleaner 12 is branched midway into two air passages 14 and 15. One air passage 14 is connected midway to the main system air passage 10, and the other air passage 15 is Pilot system air passage 1
1 to form correction air passages.

A duty solenoid valve 16 is connected to the air passage 14 connected to the main system, and an 0N-OFF solenoid valve 17 is connected to the air passage 15 connected to the pilot system.
is connected.

These solenoid valves 16 and 17 operate based on detection signal inputs from a throttle opening sensor 18 that detects the throttle opening and an engine rotation speed sensor 19 that detects the rotation speed of the engine 3. It is opened and closed by a control unit 20 that stores the amount of air supplied for the operating state.

Therefore, the operating state of the engine 3 is detected by the throttle opening sensor 18 and the engine speed 19, and based on the input of the detection signal, the control unit 20
The opening and closing of the solenoid valves 16 and 17 are controlled by the solenoid valves 16 and 17. This increases the amount of air in the low and medium speed ranges, preventing overconcentration of the mixture, and enables precise control of the air-fuel ratio, especially in the medium speed range where both the pilot system and the main system contribute. .

Note that if a duty solenoid valve 16 is used in the air passage 14 to the main system, fine control over a wide range from low speed range to high speed range is possible.
If you only need to control the low range, use 0N-O.
An FF solenoid valve may also be used.

By controlling the duty of the valve by the duty solenoid valve 16, the air flow rate is controlled as shown in FIG. This air flow rate is controlled by, for example, the length of the ON signal.

tON+tOFF increases, and by continuously changing the tON time, the air flow rate can also be changed continuously, and the air flow rate can be greatly changed.

Therefore, the opening degree of the duty solenoid valve 16 is
It is controlled (duty control) through the control unit 20 by detecting the throttle opening degree and engine speed, and the duty solenoid valve 16 measures the air flow rate to supply the amount of air according to the operating condition, thereby achieving the optimal air-fuel ratio. The air-fuel mixture is sucked into the engine 1, and precise control can be performed continuously.

Although the above-described embodiment makes it possible to supply the optimum air-fuel mixture for the engine speed and throttle opening, the temperature inside the combustion chamber is low at low temperatures or immediately after starting.
Also, because the air density is high, the air-fuel ratio becomes lean, which tends to cause engine stalling, unstable idling, and poor ride feel.

In order to solve this problem, the temperature sensor 21 is
The detection signal of this temperature sensor 21 is input to the control unit 20, and as a result, the solenoid valve 1
By changing the opening/closing or aperture ratio characteristics of 6.17, the air-fuel ratio in the carburetor 5 is changed, and the amount of air supplied is reduced to obtain an optimal mixture at low temperatures, thereby diluting the mixture. Try to prevent it. As the temperature sensor 21, it is preferable to use a cooling water temperature sensor that detects the engine cooling water temperature inside the shell, but it can also be replaced with an oil temperature sensor, engine temperature sensor, or air temperature sensor, and if necessary, an external cooling water temperature sensor can be used. By adjusting the opening degree of the solenoid valve in addition to the temperature as a condition, it is possible to prevent the mixture from becoming diluted.

The opening/closing and opening degree changes of the solenoid valves 16 and 17 are controlled as shown in FIG. 6(A) showing the opening degree of the duty solenoid valve 16 and FIG. 6(B) showing the opening/closing of the solenoid valve 17. . That is, the opening degree of the duty solenoid valve 16 is halved, and the opening degree of the solenoid valve 17 is reduced by half.
will remain closed.

Furthermore, when operating under conditions of low atmospheric pressure, such as at high altitudes, the air density is lower than on flat ground, so the air-fuel mixture tends to be too rich, causing problems with engine rotation. Therefore, as shown in FIG. 7, an atmospheric pressure sensor 22 is provided, and the detection signal output of this atmospheric pressure sensor 22 is inputted to the control unit 20 to change the opening characteristics of the solenoid valves 16 and 17, thereby controlling the carburetor 5. The air-fuel ratio is changed to prevent the mixture from becoming too rich. Regarding the opening/closing and opening degree changes of the solenoid valves 16 and 17, the duty solenoid valve 16 increases the opening degree as shown in Fig. 8 (A), and the opening time of the solenoid valve 17 increases as shown in Fig. 7 (B). controlled so that

Note that the duty solenoid valve 16 and the solenoid valve 17 can be replaced with linear solenoid valves, and in this case, the opening degree can be changed linearly as shown in FIG. 9, allowing for more precise control. becomes possible.

〔Effect of the invention〕

As described above, according to the present invention, air is supplied to both the main system air passage and the pilot system air passage, and this is done via a solenoid valve that opens and closes depending on the throttle opening and engine speed. This makes it possible to prevent the mixture from becoming enriched, especially in the medium and low speed ranges, and to finely control the air-fuel ratio.

In addition to this, it is possible to prevent the mixture from becoming diluted at low temperatures by inputting the detection signal from the temperature sensor to the control unit at low temperatures. By inputting the detection signal to the control unit, over-enrichment of the air-fuel mixture at high altitudes can be prevented.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of the intake air control device for a motorcycle engine according to the present invention, and FIG.
3 is a side view of a motorcycle implementing this invention, FIG. 4 is a diagram showing each side of duty control by the duty solenoid valve provided in this invention, and FIG. Fig. 5 is a system configuration diagram showing the intake control device for a motorcycle engine of the present invention when used for low temperature applications, and Figs. 6 (A) and (B) show duty solenoid valves in the embodiment of Fig. 5. FIG. 7 is a system configuration diagram showing the intake control device for a motorcycle engine of the present invention when used at high altitudes, and FIGS. 8(A) and (B) are Fig. 7 is a diagram showing the opening/closing control of the duty solenoid valve and the solenoid valve in the embodiment, Fig. 9 is a graph showing changes in opening when using a beam solenoid, and Fig. 10 is a conventional motorcycle engine. FIGS. 11(A) and 11(B) are graphs showing the relationship between the engine speed and the air-fuel ratio when the engine is partially opened and when the engine is fully opened.

Claims (1)

[Claims] 1. The air passage from the air filter is branched into two air passages connected to the main system and pilot system of the carburetor, and a solenoid valve is installed in the air passage connected to the main system and the pilot system. An air intake control device for a two-wheeled motor vehicle engine, characterized in that the solenoid valves are opened and closed through a control unit that is operated according to throttle opening and engine speed. 2. The automatic engine according to claim 1, wherein the control unit controls the opening degree of the solenoid valve based on the detection result of the temperature sensor at low temperature startup to prevent the air-fuel ratio from becoming lean at low temperatures. Intake control device for motorcycle engines. 3. According to claim 1, the control unit controls the opening degree of the solenoid valve based on the detection result of the atmospheric pressure sensor at the time of starting at high altitudes, thereby preventing excessive concentration of the air-fuel ratio at the time of starting at high altitudes. Air intake control device for motorcycle engines.