JPH04140445A - Idle speed control device - Google Patents

Abstract

PURPOSE:To hold a target idle speed by introducing the outside air by a bypass passage at idle operation time of an internal combustion engine, drive-controlling a control valve so as to hold an engine speed to the target idle speed, and compensating a drop of the engine speed due to decrease of air density in the high ground. CONSTITUTION:In an internal combustion engine in which each throttle body 16 is provided to communicate with a single air cleaner box 18 while providing the two throttle bodies 16 for each combustion chamber to respectively communicate with a crankcase, a bypass pipe 70, comprising one main bypass pipe 70 and two branch bypass pipes 70b, is provided, and in the main bypass pipe 70a, the upstream is connected to a control valve 68 by a connection pipe 72 and also connecting the downstream to the upstream of each branch bypass pipe 70b by a branch part 70c, to connect the downstream of each branch bypass pipe 70b respectively to the throttle body 16. The control valve 68 is drive- controlled so as to hold an engine speed to a target idle speed by introducing the outside air to an intake passage 20 in the downstream of a throttle valve 22 by a bypass passage 66 at idle operation time of the internal combustion engine 2.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an idle rotation control device, and particularly to an apparatus for controlling engine rotation speed to a target idle rotation speed in response to changes in altitude without particularly providing an atmospheric pressure sensor. The present invention relates to an idle rotation control device that can be maintained.

[Conventional technology]

An example of an idle rotation control device for maintaining the engine rotation speed of an internal combustion engine at a target idle rotation speed is shown in FIGS. 7 and 8. In the figure, 202 is an internal combustion engine, 204 is an intake passage, 206 is a throttle valve, 208 is a bypass passage, and 210 is a control valve. The internal combustion engine 202 is provided with a bypass passage 208 that communicates the intake passage 204 between the upstream side and the downstream side of the slow valve 206, and a control valve 21 that controls the amount of bypass air in the bypass passage 208.
0 is provided, and when the internal combustion engine 202 is idling, bypass air is introduced from the upstream side of the throttle valve 206 to the downstream side of the intake passage 204 depending on the air amount etc. to control the engine speed to be maintained at the target idle speed. The valve 210 is driven and controlled. In addition, the code|symbol 212 is a fuel injection valve, and 214
216 is an intake pressure sensor, and 216 is a control unit.

Further, as a device for controlling the engine speed of an internal combustion engine to a target idle speed, there is a method disclosed in Japanese Patent Laid-Open No. 1-155044. What is disclosed in this publication is an electronically controlled fuel injection device that controls a fuel injection valve to inject and supply a fuel injection amount set based on engine rotational speed and intake pressure. An engine idling operation detection means is provided, and when the atmospheric pressure decreases when the internal combustion engine is idling, the amount of intake air is increased in the intake passage from the upstream side of the throat/nottle valve to the downstream side by more than the decrease in air density. By providing intake air amount increasing means that is introduced at high altitudes, the air-fuel ratio is prevented from becoming thinner due to a decrease in air density at high altitudes, and the engine speed is maintained at the target idle speed.

[Problem that the invention seeks to solve]

By the way, some internal combustion engines are injected and supplied with a fuel amount calculated from an engine rotational speed and a throttle opening degree using a fuel injection valve. For this target idle speed of the internal combustion engine, the idle opening of the throttle valve is determined by an initial setting value, and the amount of air is determined by the opening area of the throttle valve at the idle opening.

However, due to the difference in air density between flatlands and highlands, if the idle opening of the sea urchin throttle valve is set to reach the target idle speed on flatland, the engine speed will not match the target idle speed due to the decrease in air density at highlands. This results in a problem of deterioration.

For this reason, in an internal combustion engine in which the amount of fuel calculated from the engine speed and throttle opening as described above is injected and supplied by a fuel injection valve, the idle opening of the throttle valve is adjusted so that the target idle speed is reached on flat ground. If this setting is made, it is necessary to set the idle opening degree again so that the target idle rotation speed is reached at high altitudes, which causes the inconvenience that the setting work becomes complicated. If this process of setting the idle opening of the throttle valve is left unattended at high altitudes, the warm-up performance of the internal combustion engine at high altitudes when starting at low temperatures will be degraded. There are disadvantages that are disadvantageous in usage conditions for vehicles that are required to do what is possible.

In this case, as disclosed in the above publication, an atmospheric pressure sensor is provided to detect the atmospheric pressure, and the atmospheric pressure detected by the atmospheric pressure sensor is used to increase the amount of intake air in response to changes in altitude, thereby achieving the target engine speed. It can also be held at idle speed. However, the separate provision of the atmospheric pressure sensor has the disadvantage of increasing costs. Further, as disclosed in the above-mentioned publication, an intake pressure sensor that detects intake pressure is used in an internal combustion engine that is controlled so that a fuel injection valve injects and supplies a fuel injection amount set based on engine rotational speed and intake pressure. If the configuration is such that the atmospheric pressure is detected, there is a problem that the atmospheric pressure cannot be detected depending on the operating state of the internal combustion engine.

[Purpose of the invention]

Therefore, an object of the present invention is to appropriately maintain the engine speed at a target idle speed in response to changes in altitude without providing an atmospheric pressure sensor, and thereby adjust the throttle speed so that the engine speed reaches the target idle speed on flat ground. When the idle opening degree of the valve is set, it is not necessary to set the idle opening degree again at high altitudes, making the setting work easier, and improving the warm-up performance when starting the internal combustion engine at low temperature at high altitudes, Another object of the present invention is to realize an idle rotation control device that can be advantageous in usage situations for vehicles that are required to be able to start immediately after starting.

[Means for solving problems]

In order to achieve this object, the present invention bypasses a throttle valve provided in an intake passage of an internal combustion engine to be injected and supplied with a fuel amount calculated from an engine speed and a throttle opening by a fuel injection valve to an upstream side. A bypass passage is provided which is open to the outside air and communicates downstream with the intake passage downstream of the throttle valve, and a control valve is provided to control bypass air t in the bypass passage, and when the internal combustion engine is idling, the bypass passage is connected to the intake passage downstream of the throttle valve. The present invention is characterized in that a control means is provided for driving and controlling the control valve to maintain the engine speed at a target idle speed by introducing outside air into the intake air path on the downstream side of the throttle valve.

[Effect]

According to the configuration of the present invention, the control means drives the control valve to maintain the engine speed at the target idle speed by introducing outside air into the intake passage downstream of the throttle valve through the bypass passage during idling operation of the internal combustion engine. By controlling the idle opening of the throttle valve to reach the target idle speed on flat ground, if the engine speed falls below the target idle speed due to a decrease in air density at high altitude, the control valve By driving and controlling the engine, outside air can be introduced into the intake passage downstream of the throttle valve, increasing the engine speed and maintaining it at the target idle speed.

〔Example〕

Next, embodiments of the present invention will be described in detail based on the drawings.

1 to 6 show an embodiment of an idle rotation control device according to the present invention. In Fig. 6, 2 is an internal combustion engine, 4 is a crank chamber, 6 is a crankshaft, 8 is a combustion chamber, and l
O is a piston, and 12 is a spark plug. The internal combustion engine 2 in this embodiment is a so-called two-stroke internal combustion engine in which two strokes, a scavenging and compression stroke and an expansion and suction stroke, are performed during one rotation of the crankshaft 6, and these strokes constitute one cycle. Further, this internal combustion engine 2 is mounted on a vehicle (not shown).

A throttle body 16 is connected to a crankcase 14 forming a crank chamber 4 of the internal combustion engine 2 .

An air cleaner box 18 is connected to the throttle body 16. The crank chamber 4 communicates with an intake passage 20 formed by a throttle body 16 and an air cleaner box I8. An intake passage 20 formed in the throttle body 16 is provided with a throttle valve 22 and a fuel injection valve 24 directed toward the crank chamber 4 .

Further, the spark plug 12 provided in the combustion chamber 8 is connected to an ignition circuit 26. The ignition circuit 26 causes the ignition Brague 2 to spark in response to a signal input from a pink-up 28 that is rotationally driven by the crankshaft 6.

Note that the internal combustion engine 2 in this embodiment has two combustion engines 16 for each combustion chamber S, as shown in FIGS. 1 to 3.
- Each throttle body 16 is connected to the crank case 14, and each throttle body 16 is connected to a single air cleaner box 18. This results in
Each throttle body 16 has an intake passage 2o.
・2 degrees are formed, and each throttle valve 2
2 and 22 are provided, and each throttle body 16 and
16 are provided with fuel injection valves 24, 24, respectively.

The intake passage 2 is regulated by the throttle valve 22.
The air flowing through the air and the fuel injected and supplied by the fuel injection valve 24 form a mixture that flows into the crank chamber 4, is supplied to the combustion chamber 8, is ignited and burnt by the spark plug 12, and is passed through the exhaust passage (not shown). is discharged to the outside. This combustion causes the piston 10 to drive the crankshaft 6. The driving force of the internal combustion engine 2 taken out by the crankshaft 6 is transmitted, for example, from a clutch mechanism (not shown) to a traveling mechanism via a transmission mechanism to drive a vehicle (not shown).

The fuel injection valve 24 is communicated with a fuel tank 32 through a fuel supply passage 3o. A fuel pump 34 for pumping fuel and a fuel filter 36 for removing dust from the fuel are provided in the middle of the fuel supply passage 30. Further, the fuel injection valve 24 is communicated with the fuel tank 32 through a fuel pressure adjustment passage 38 . A fuel pressure regulating valve 40 is provided in the middle of this fuel pressure regulating passage 38 . The fuel pressure regulating valve 40 regulates the fuel pressure fed to the fuel injection valve 24 to a predetermined pressure by the intake pressure of the intake passage 20 downstream of the throttle valve 22, and drains excess fuel into the fuel tank via the fuel pressure regulating passage 38. Return to 32.

The fuel injection valve 24 is connected to a control section 44 as a control means via a resistor 42. Further, the fuel pump 34 is connected to a control unit 44 via a pump relay 46, and is supplied with and disconnected from a battery 56, which will be described later.

The control unit 44 includes an ignition circuit 26 for detecting the engine speed, a throttle opening sensor 48 for detecting the throttle opening of the throttle valve 22, and a water temperature sensor 50 for detecting the temperature of the cooling water of the internal combustion engine 2. , and an intake air temperature sensor 52 that detects intake air temperature.

The control unit 44 also includes a control unit relay 5 that supplies and disconnects power.
4 to a battery 56. Control unit relay 54 is connected to battery 56 via ignition switch 58. The control unit relay 54 is turned on and off by an ignition switch 58 to supply and disconnect power to the control unit 44 . Note that the reference numeral 60 indicates the control unit relay 54.
This is a control unit relay fuse interposed between the battery 56 and the battery 56. Reference numeral 62 indicates an ignition switch fuse interposed between the ignition switch 58 and the battery 56. Further, reference numeral 64 indicates the pump relay 4
This is a pump relay fuse interposed between the battery 56 and the battery 56.

The control unit 44 drives and controls the fuel injection valve 24 based on signals input from the sensors 26 and 48 to 52.

That is, at times other than when the internal combustion engine 2 is started, drive control is performed to inject and supply the fuel amount calculated from the map of the engine rotational speed N and the throttle opening degree α by basic fuel injection control.

In this way, the throttle valve 2 provided in the intake passage 20 of the internal combustion engine 2 is injected and supplied with the fuel amount calculated from the engine speed N and the throttle opening degree α by the fuel injection valve 24.
2, a bypass passage 66 is provided which opens the upstream side to the outside air and communicates the downstream side with the intake passage 20 downstream of the throttle valve 22.
A control valve 68 is provided to control the amount of bypass air in the intake passage 2 downstream of the throttle valve 22.
0 and maintains the engine speed at the target idle speed.

In this embodiment, as shown in FIGS. 1 to 3, a bypass pipe 7o forming a bypass passage 66 is provided. The bypass pipe 7o consists of one main bypass pipe 70a and two branch bypass pipes 70b. The main bypass pipe 70a is connected to the control valve 6 by a connecting pipe 72 (described later) on the upstream side.
8, and the upstream sides of the branch bypass pipes 70b and 70b are connected to each other at the branch portion 70c on the downstream side.

The downstream side of each branch bypass pipe 70b, 70b communicates with the throttle body 16, 16, respectively.

Further, as shown in FIG. 4, the control valve 68 has a main body passage 68b in the main body 6a attached to the air cleaner box 18, and a valve seat 68c (not shown) provided in the middle of this main body passage 68b. A valve body 68d is provided which is brought into contact and separated by a solenoid and a spring. A solenoid (not shown) of the control valve 68 is connected to the control section 44 . Further, the main body passage 68a has an outside air port 6 facing the outside air on the upstream side.
8e, and the downstream side is connected to the upstream side of the main bypass pipe 70a via a connecting pipe 72. In addition, the code|symbol 68f is a filter.

Bypass passage 66 formed by the bypass pipe 70
As shown in FIG. 3, there is a main bypass passage 66a formed by the main bypass pipe 70a, and each branch bypass pipe 70.
Each branch bypass passage 66b formed by b.70b
・Consists of 66b.

The main bypass passage 66a communicates with the main body passage 68b of the control valve 68 on the upstream side through a connecting passage 72a of the connecting pipe 72, and on the downstream side with the branch bypass passages 66b at a branch point 66c. The downstream side of each branch bypass passage 66b, 66b communicates with each intake passage 20, 20 downstream of the throttle valve 22, 22 of each throttle body 16, 16.

In addition, the symbols 74 and 74 indicate each branch bypass passage 66b and
66b. The throttle portions 74, 74 adjust the amount of bypass air in accordance with the air-fuel ratio of the air-fuel mixture supplied to each combustion chamber 8, 8.

Next, the operation will be explained according to FIG.

When the control starts (100), the control unit 44 determines whether or not the internal combustion engine 2 is in an idling operation in which the cooling water temperature is lower than a predetermined temperature at the time of starting (101).

If the cooling water temperature exceeds the predetermined temperature at the time of starting the internal combustion engine 2 (101: No), the process ends (104).

If the cooling water temperature is lower than the temperature when starting the internal combustion engine 2 (101:
If YES), it is determined whether the engine speed is the target idle speed (102).

When the engine speed is the target idle speed (l O2
: YES) becomes the end (104).

On the other hand, if the engine speed is not the target idle speed (I
OINO) drives and controls the control valve 68 (103) so as to introduce outside air into the intake passage 20 downstream of the throttle valve 22 through the bypass passage 66 to maintain the engine speed at the target idle speed; )become.

As a result, when the internal combustion engine 2 is idling, the control unit 44 introduces outside air as bypass air into the intake passage 20 on the downstream side of the throttle valve 22 through the bypass passage 66 to maintain the engine speed at the target idle speed. , drive control of the control valve 68 variably or intermittently.

That is, the control unit 44 variably or intermittently controls the valve body 68d of the control valve 68 during idling operation of the internal combustion engine 2, and uses the outside air taken in from the outside air port 68e of the control valve 68 as bypass air for the main body. Passage 68b, connection passage 72
a. The intake air is introduced from the main bypass passage 66a through the branch point 66c to each intake passage 20, 20 downstream of each throttle valve 22, 22 through each branch bypass passage 66b, 66b, and maintains the engine speed at the target idle rotation speed. do.

As a result, the idle opening degree of the throttle valve is set so that the target idle speed is reached on flat ground, and when the engine speed falls below the target idle speed due to a decrease in air density at high altitudes, the control valve 68 is set. Drive control is performed to introduce outside air into the intake passage 20 on the downstream side of the throttle valve 22, compensate for the decrease in engine speed due to a decrease in air density with bypass air, and increase the engine speed to maintain it at the target idle speed. be able to.

Therefore, the engine speed can be appropriately maintained at the target idle speed in response to changes in altitude without providing an atmospheric pressure sensor. Throttle valve 16 again at high altitude when setting idle opening
It is possible to make the setting work easier by eliminating the need to set the idle opening degree of the engine, and it is possible to improve the warm-up performance when starting the internal combustion engine 2 at low temperatures at high altitudes. This makes it possible to start immediately, which can be advantageous for vehicles such as snowmobiles that are required to be able to start immediately after starting.

In addition, by controlling the control valve 68 variably or intermittently to introduce outside air, the control range of the air-fuel ratio of the air-fuel mixture can be expanded, and the warm-up performance can be further improved. It is possible to prevent scuffing of the piston when the engine is cold, suppress large fluctuations in the target idle rotation speed, and maintain the target idle rotation speed.

Furthermore, each intake passage 2 of each throttle body 16.
Each branch bypass passage 66b, 6 communicating with 0, 20
6b is provided with throttle portions 74, 74 to adjust the amount of bypass air in accordance with the air-fuel ratio of the air-fuel mixture supplied to each combustion chamber 8, 8. This can solve the problem that, especially in two-stroke internal combustion engines, the scavenging characteristics of the atrium change depending on the shape of the exhaust system such as the muffler that communicates with each combustion chamber, resulting in variations in output, and balance the output. be able to.

〔Effect of the invention〕

As described above, according to the present invention, the control means operates the control valve to maintain the engine speed at the target idle speed by introducing outside air into the intake passage on the downstream side of the throttle valve through the bypass passage during idling operation of the internal combustion engine. By controlling the drive, the idle opening of the throttle valve is set so that the target idle speed is reached on flat ground, and the engine speed is set to the target idle speed J due to the decrease in air density at high altitudes.
If the temperature drops below , the control valve is actuated to direct outside air to the intake passage downstream of the throttle valve.

However, the decrease in engine speed due to the decrease in air density is compensated for by the Neubus air, and the engine speed can be increased and maintained at the target idle speed.

Therefore, without installing an atmospheric pressure sensor, it is possible to appropriately maintain the engine speed at the target idle speed in response to changes in high altitudes. It is not necessary to set the idle opening of the C throttle valve again at high altitude when the opening is set, and the setting work can be made easier, and the warm-up performance at low temperature start of a V-fuel engine at high altitude can be improved. hand,
In addition, this is advantageous for vehicles that require the ability to start immediately after starting.

In addition, by controlling the control valve and introducing outside air, it is possible to expand the control range of the air-fuel ratio of the mixture, further improving warm-up performance, and reducing piston scuffing when the engine is cold. Therefore, large fluctuations in the target idle rotation speed can be suppressed and the target idle rotation speed can be maintained at the target idle rotation speed.

[Brief explanation of the drawing]

1 to 6 show embodiments of the present invention, FIG. 1 is a schematic diagram of an idle rotation control device, FIG. 2 is a schematic diagram of a bypass pipe and control valve, and FIG. 3 is a schematic diagram of an idle rotation control device. FIG. 4 is a schematic plan view, FIG. 4 is a sectional view of a main part of the control valve, FIG. 5 is a control flowchart, and FIG. 6 is a schematic diagram of an internal combustion engine equipped with an idle rotation side '+B device. FIGS. 7 and 8 are schematic configuration diagrams showing conventional examples of idle rotation control devices, respectively. In the figure, 2 is an internal combustion engine, 8 is a combustion chamber, 14 is a crankcase, 16 is a throttle body, 18 is an air cleaner box, 20 is an intake passage, 22 is a throttle valve, 24 is a fuel injection valve, 26 is an ignition circuit, 44 is the control section,
48 is a throttle opening sensor, 50 is a water temperature sensor, 52
is an intake temperature sensor, 56 is a battery, 58 is an ignition switch, 66 is a bypass passage, 68 is a III control valve, 7
0 is a bypass pipe, 72 is a connecting pipe, and 74 is a constriction part. Patent applicant Suzuki Automobile Industry Co., Ltd.

Claims (1)

[Claims] 1. The amount of fuel calculated from the engine speed and throttle opening is injected and supplied by the fuel injection valve, bypassing the throttle valve installed in the intake passage of the internal combustion engine, opening the upstream side to the outside air, and opening the downstream side to the outside air. A bypass passage communicating with the intake passage on the downstream side of the throttle valve is provided, and a control valve is provided for controlling the amount of bypass air in the bypass passage, and when the internal combustion engine is idling, the bypass passage directs outside air to the intake passage on the downstream side of the throttle valve. An idle rotation control device comprising: control means introduced into an intake passage to drive and control the control valve to maintain engine rotation speed at a target idle rotation speed.