JPH0444099B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for an internal combustion engine, and in particular, by improving the valve opening means at startup, the secondary throttle valve is maintained open for a predetermined period of time even after the cranking operation is completed, thereby improving engine performance. The present invention relates to an intake system for an internal combustion engine that is designed to improve the performance.

In order to improve the startability and the transition characteristics in which the secondary intake system is added, an intake system is provided with a start valve opening means for opening the carburetor secondary throttle valve to a predetermined opening degree during cranking, which is disclosed in this application. The invention was made by the inventor of , and an application has already been filed. However, although this conventional device has a significant effect on improving engine performance, it is configured to apply negative pressure in the intake pipe to the opening means of the carburetor secondary throttle valve only during cranking, and it does not fully achieve its purpose. It also has some inconveniences.

Therefore, an object of the present invention is to connect a negative pressure port of a negative pressure passage communicating with a diaphragm chamber of an actuator downstream of the carburetor primary throttle valve in order to open and close the carburetor secondary throttle valve of a dual-intake internal combustion engine using negative pressure. A three-way negative pressure switching valve is installed connected to the primary intake passage for low loads, and is operated by the cranking signal of the ignition switch from the negative pressure port side in the middle of the negative pressure passage. and a delay means for holding the pressure even after cranking is completed to delay the closing operation of the carburetor secondary throttle valve,
The delay means includes a negative pressure delay valve and a volume that has a one-way valve that conducts only in the direction of the negative pressure source and holds the delay intake pipe negative pressure in parallel, and the start valve opening means having the delay means is configured. By installing this, the closing operation of the carburetor secondary throttle valve is delayed by the regulator after cranking is completed, and high idle, vapor from the secondary slow system, and fuel suction are further maintained, resulting in early demodulation of the engine. An object of the present invention is to provide an intake device for an internal combustion engine that has improved connection characteristics and startability through functionalization.

Another object of the present invention is to provide a starting valve opening means having at least one temperature sensing valve in the detour path that bypasses the three-way negative pressure switching valve, so that the engine set temperature can be adjusted to stabilize idling. Open the carburetor secondary throttle valve to a predetermined opening until the
To provide an intake device for an internal combustion engine that can maintain high idling for a predetermined period of time, reliably stabilize idling, and achieve earlier demodulation of the engine.

Hereinafter, embodiments of the present invention will be described in detail and specifically based on the drawings. In FIG. 1 showing the first embodiment, 2 is a low-load primary side carburetor, 4 is a high-load secondary side carburetor, 6 is a low-load primary intake passage,
8 is a secondary intake passage for high loads, 10 is an intake manifold, 12 is a throttle body, 14 is an actuator constituting a starting operating means, 16 is an acceleration pump, 18 is a secondary valve opening means consisting of a diaphragm, and 20 is a carburetor. A primary throttle valve, and 22 a carburetor secondary throttle valve.

In the secondary intake passage 8, a secondary throttle valve 22 is provided in the throttle body 12 in close proximity to a combustion chamber (not shown), and the secondary throttle valve 22 is operated in a low load range, particularly not only during cranking but also during idling. In order to improve the stability of warm-up rotation by opening the valve to a predetermined opening degree, a starting valve opening means 24 is provided.
That is, to explain the valve opening mechanism, 2
A main lever 28 for opening and closing the secondary throttle valve 22 is fixed to the throttle valve shaft 26 of the secondary throttle valve 22, and an auxiliary lever 32 having a pin 30 is rotatably mounted on the throttle valve shaft 26. Further, the sub-lever 32 and the diaphragm 34 of the actuator 33 are connected via an operating rod 36.

In addition, the secondary slow passage 38 is opened and terminated in the opening/closing regulation area of the secondary throttle valve 22, and the secondary slow port 4
Set 0. Then, when the intake pipe negative pressure acts on the diaphragm chamber 42 of the actuator 33, the pin 30 of the sub-lever 32 is moved to the main lever 28.
is rotated in the valve opening direction L, thereby opening the secondary throttle valve 22 by a predetermined opening degree.

Further, a negative pressure port 44 is provided in the primary intake passage 6 on the downstream side of the primary throttle valve 20, and a first port 50 of a three-way negative pressure switching valve 48, such as an electric type, is provided through the first negative pressure passage 46. communicate with. This three-way negative pressure switching valve 48 is switched between the A port 50 and the O port 53 by a cranking signal from the ignition switch 52.
are configured so that they communicate. The three-way negative pressure switching valve 48 also has a C port 54 that communicates with the atmosphere.
At the same time, the second negative pressure passage 56 connects the O port 53 to the actuator 1 of the starting operation means.
Connect to 4. A third negative pressure passage 58 is provided that branches from the second negative pressure passage 56, and this third negative pressure passage 58 is further branched to provide fourth and fifth negative pressure passages 60, 62 in parallel. pressure passage 60,
62 is integrated into a sixth negative pressure passage 64, and this sixth negative pressure passage 64 is connected and terminated to the diaphragm chamber 42 of the actuator 33 constituting the valve opening means 24 at startup. A fourth delay means 66 for delaying the closing operation of the secondary throttle valve 22 at the end of cranking is provided.
It is provided in the middle of the fifth negative pressure passages 60 and 62. In other words, the fourth negative pressure passage 60 is equipped with a VTV (vacuum transmitting valve, so-called delay valve).
Further, the fifth negative pressure passage 62 is provided with a volume 70 having a one-way valve 72 that opens only in the direction of an arrow 71. As a result, the closing operation of the secondary throttle valve 22 is delayed for a while after cranking is completed, and even after idling has started, the secondary throttle valve 22 is opened to a predetermined opening for a desired time, allowing high idle and secondary slow system functions. It was designed to achieve the goal of achieving a

In addition, the acceleration pump 16 is operated during cranking, and the acceleration pump 16 is operated during cranking.
6 and the vapor in its conduit are discharged to make the acceleration system functional.

Next, the effect will be explained.

During cranking operation, the cranking signal generated by operating the ignition switch 52 causes
The passage of the three-way negative pressure switching valve 48 is switched, and the A port 50 and the O port 53 communicate with each other. Therefore, the intake pipe negative pressure first reaches the delay means 66 from the negative pressure port 44 via the first and third negative pressure passages 46 and 58. In this delay means 66, the intake pipe negative pressure is stored in the volume 70 via the one-way valve 72, and is further transmitted to the diaphragm chamber 42 of the actuator 33. Therefore, the diaphragm 34 is attracted toward the diaphragm chamber 42, and the operating rod 36
The secondary throttle valve 32 is rotated counterclockwise, that is, in the direction of arrow L, and the pin 30 is used to push and rotate the main lever 28, thereby opening the secondary throttle valve 22 by a predetermined opening degree. Therefore, the secondary slow port 40
is located on the downstream side of the secondary throttle valve 22, and the vapor due to percolation in the secondary slow passage 38 is sucked, thereby improving the connection characteristics at the time of transition to the secondary intake system. Also, by opening the secondary throttle valve 22, fresh air can be taken in.
It is possible to dilute the overconcentration of the air-fuel mixture due to percolation occurring in the primary side carburetor 2, etc., and restartability is improved.

Furthermore, when starting the engine cold, fuel can be supplied from the secondary slow passage 38 by opening the secondary throttle valve, thereby improving startability.

Next, upon completion of the cranking operation, the cranking signal of the ignition switch 52 becomes
OFF, and as a result, the three-way negative pressure switching valve 4
8 passage is switched, Otsu port 53 and C port 5
4, the third negative pressure passage 58 is opened to the atmosphere, and the atmosphere reaches the delay means 66 portion. In the delay means 66, the one-way valve 72 prevents the atmospheric air from being transmitted to the volume 70 due to the non-return action, but the negative pressure delay valve 68 gradually transmits the atmospheric air to the volume 70 via the fourth negative pressure passage 60. be done. Therefore, although the negative pressure stored in the volume 70 gradually decreases, the decrease in the operating negative pressure of the actuator 33 to the diaphragm chamber 42 is delayed by a predetermined period of time. Therefore, the closing operation of the secondary throttle valve 22 is also delayed, and as a result, the high idle described in the previous section, vapor from the secondary slow system, and fuel suction are further maintained, resulting in early demodulation and functional state of the engine. This improves the connecting properties and startability.

2 and 3 show the second and third embodiments, respectively.

These second and third embodiments are characterized in that they are provided with a sensitivity sensing valve that opens the secondary throttle valve 22 to a predetermined opening within the engine set temperature range in order to achieve early demodulation after the engine is started.

That is, in the second embodiment shown in FIG. 2, in order to bypass the three-way negative pressure switching valve 48, the seventh negative pressure passage is a bypass passage that short-circuits the first negative pressure passage 46 and the sixth negative pressure passage 64. 76, and in the middle of this seventh negative pressure passage 76 there is a single temperature sensing valve 78 (BVSV: normal vacuum switching) that opens when the engine temperature is below the set temperature and closes when the engine temperature reaches the set temperature.・Bimetal is incorporated into the valve, and a bimetal vacuum switching valve, etc. is installed that closes the bimetal contact and opens the valve at a predetermined temperature.

In addition, in the third embodiment shown in FIG. 3, the seventh negative pressure passage 76 includes a first temperature sensing valve 80 that opens at a temperature equal to or higher than the first set temperature of the engine, and a second set temperature that is higher than the first set temperature. A second temperature sensing valve 82 that closes as described above is provided.

If configured as in the second and third embodiments described above, the following effects will be obtained in addition to the effects of the first embodiment. In other words, in the second embodiment, if the set temperature is set to a temperature that is sufficient for a period sufficient to stabilize idling, the temperature sensing valve 78 detects the intake air not only during cranking but also after the engine starts until the engine temperature reaches the set temperature. A negative pressure is applied to the diaphragm chamber 42 of the actuator 33 to keep the secondary throttle valve 22 open by a predetermined opening degree, thereby maintaining high idle for a predetermined period of time, reliably stabilizing the idling, and improving engine speed. can achieve early demodulation.

Furthermore, if configured as in the third embodiment, when the engine temperature reaches the first set temperature, the first temperature sensing valve 80 opens, the intake pipe negative pressure is transmitted to the actuator 33, and the secondary throttle valve 22 opens to a predetermined opening. It will be released. When the engine temperature further increases and reaches the second set temperature,
The second sensing valve 82 cuts off the transmission of the intake pipe negative pressure, and the secondary throttle valve 22 returns to the fully closed state after a set time has elapsed. This allows the engine to go into high idle after it has slightly left the completely cold state.
Efficient early stabilization is possible with a small amount of fuel.

As is clear from the above description, according to the present invention, the negative pressure port of the negative pressure passage communicating with the diaphragm chamber of the actuator is connected to the carburetor 1 in order to open and close the carburetor secondary throttle valve of a dual intake internal combustion engine using negative pressure. A three-way negative pressure switching valve is connected to the low-load primary intake passage on the downstream side of the secondary throttle valve, and a three-way negative pressure switching valve is installed in the negative pressure passage and is operated by the cranking signal of the ignition switch from the negative pressure port side. A delay means is provided to hold the intake pipe negative pressure generated by the cranking even after cranking is completed, and to delay the closing operation of the carburetor secondary throttle valve, and the delay means is communicated only in the direction of the negative pressure delay valve and the negative pressure source. A one-way valve is arranged in parallel with a volume that maintains negative pressure in the intake pipe for delay, and a starting valve opening means with a delay means is provided. Not only can it delay the closing operation of the valve and improve starting performance, but it can also effectively ensure high idling without affecting the engine system under lean air-fuel mixtures and improve idling stability. , it is possible to warm up the engine early, it is possible to start the engine smoothly immediately after starting the engine, it is possible to prevent plug fogging by introducing fresh air, and it is also possible to improve the connection characteristics.

In addition, since a start-up valve opening means having at least one temperature sensing valve is provided in the bypass path that bypasses the three-way negative pressure switching valve, the carburetor secondary throttle is used until the engine reaches the set temperature that stabilizes idling. By opening the valve to a predetermined opening degree, in addition to the above effects, high idle can be maintained for a predetermined period of time up to the engine set temperature.
Idling can be reliably stabilized,
This allows the engine to be demodulated more quickly.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an intake system for an internal combustion engine according to a first embodiment of the present invention, FIG. 2 is a system diagram showing an intake system for an internal combustion engine according to a second embodiment, and FIG. 3 is a system diagram showing an intake system for an internal combustion engine according to a second embodiment. It is a system diagram concerning an example. In the figure, 2 is the primary side carburetor for low load, 4 is the secondary side carburetor for high load, 6 is the primary intake passage for low load, 8 is the secondary intake passage for high load, and 20 is the carburetor 1.
A secondary throttle valve, 22 is a carburetor secondary throttle valve, 24 is a starting valve opening means, 33 is an actuator, 42 is a diaphragm chamber, 44 is a negative pressure port, 48 is a three-way negative pressure switching valve, 66 is a delay means, 68 is a negative pressure delay valve;
70 is a volume, 72 is a one-way valve, 78 is a temperature sensing valve, and 80 and 82 are first and second temperature sensing valves.

Claims (1)

[Scope of Claims] 1. A carburetor primary throttle valve provided in the middle of the low-load primary intake passage in the carburetor and a carburetor provided in the middle of the high-load secondary intake passage in the throttle body near the intake port. In a dual intake internal combustion engine having a secondary throttle valve, a negative pressure port of a negative pressure passage communicating with a diaphragm chamber of an actuator is connected to the primary throttle valve of the carburetor in order to open and close the secondary throttle valve of the carburetor using negative pressure. This is generated by cranking and a three-way negative pressure switching valve that is connected to the primary intake passage for low loads on the downstream side and is switched from the negative pressure port side in the negative pressure passage by the cranking signal of the ignition switch. A delay means is provided for holding the intake pipe negative pressure even after cranking is completed to delay the closing operation of the carburetor secondary throttle valve, and the delay means is unidirectionally connected to the negative pressure delay valve only in the direction of the negative pressure source. 1. An intake system for an internal combustion engine, comprising a valve having a valve and a volume for maintaining a delay intake pipe negative pressure in parallel, and a starting valve opening means having the delay means. 2. A carburetor primary throttle valve provided in the middle of the low-load primary intake passage in the carburetor, and a carburetor secondary throttle valve provided in the middle of the high-load secondary intake passage in the throttle body near the intake port. In a dual-intake internal combustion engine, in order to open and close the carburetor secondary throttle valve using negative pressure, the negative pressure port of the negative pressure passage communicating with the diaphragm chamber of the actuator is connected to a low-load side downstream of the carburetor primary throttle valve. A three-way negative pressure switching valve is installed connected to the primary intake passage, and is switched from the negative pressure port side in the negative pressure passage by the cranking signal of the ignition switch. A delay means is provided to hold the closing operation of the carburetor secondary throttle valve even after the ranking is completed, and a one-way valve that communicates with the negative pressure delay valve only in the direction of the negative pressure source is provided. A bypass passage that bypasses the three-way negative pressure switching valve is provided, and a bypass passage is provided in the middle of the bypass passage until the engine temperature reaches the set temperature at which idling becomes stable. An intake system for an internal combustion engine, characterized in that an intake device for an internal combustion engine is provided with a starting valve opening means having at least one temperature sensing valve that operates to open a carburetor secondary throttle valve to a predetermined opening degree and the delay means.