WO-2026094164-A1 - CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

WO2026094164A1WO 2026094164 A1WO2026094164 A1WO 2026094164A1WO-2026094164-A1

Abstract

Provided is a control device for an internal combustion engine that is used in a vehicle including a single-cylinder internal combustion engine and a centrifugal clutch engaged when the speed of the internal combustion engine has increased, and that can prevent unintended engagement of the centrifugal clutch during execution of idle operation control. When the engine speed of the internal combustion engine (2) in one cycle is plotted and a straight line connecting the maximum value of the engine speed in one cycle and the engine speed at the end of the exhaust stroke is defined as a reference line, if there is an engine speed plotted below the reference line in the exhaust stroke during execution of idle operation control, the control device (1) for the internal combustion engine controls the internal combustion engine (2) so that the engine speed decreases and prevent engagement in the centrifugal clutch (6).

Inventors

ITO YOSHIHITO

Assignees

ヤマハ発動機株式会社

Dates

Publication Date: 20260507
Application Date: 20241030

Claims (4)

A control device for an internal combustion engine used in a vehicle equipped with a single-cylinder internal combustion engine and a centrifugal clutch that engages when the rotational speed of the internal combustion engine increases, and which performs idle operation control, When plotting the rotational speed of the internal combustion engine during one cycle, if we define the line connecting the maximum value of the rotational speed of the internal combustion engine during one cycle and the rotational speed of the internal combustion engine at the end of the exhaust stroke as the baseline, A control device for an internal combustion engine, which controls the internal combustion engine to reduce its rotational speed when, during the execution of the idle operation control, the rotational speed of the internal combustion engine is plotted below the reference line during the exhaust stroke.
A control device for an internal combustion engine according to claim 1, The centrifugal clutch is configured to transmit the rotation of the internal combustion engine to the power transmission means when engaged. The control device for the internal combustion engine controls the internal combustion engine to reduce its rotational speed when, during the execution of the idle operation control, the rotational speed of the internal combustion engine is plotted below the reference line during the exhaust stroke and the rotation of the internal combustion engine is not transmitted to the power transmission means.
A control device for an internal combustion engine according to claim 1, If we divide the exhaust stroke into two parts, defining the region closest to the combustion stroke as the first half of the exhaust stroke and the other region as the second half of the exhaust stroke, A control device for an internal combustion engine, which, while performing the idle operation control, controls the internal combustion engine to reduce its rotational speed if the load acting on the internal combustion engine in the first half of the exhaust stroke is greater than the load acting on the internal combustion engine in the second half of the exhaust stroke.
A control device for an internal combustion engine according to claim 1 or 2, A control device for an internal combustion engine, which, when it is detected during the execution of the idle operation control that there is a rotational speed of the internal combustion engine plotted below the reference line during the exhaust stroke, controls the internal combustion engine so as to reduce the area of the region formed by the rotational speed of the internal combustion engine plotted below the reference line and the reference line.

Description

Control device for internal combustion engines This invention relates to a control device for an internal combustion engine. A control device for internal combustion engines, applied to internal combustion engines mounted in vehicles and performing idle operation control when the engine is idling, is known. For example, Patent Document 1 discloses a control device for internal combustion engines that performs early activation of the exhaust gas purification catalyst during idle operation control. According to this control device, when the temperature of the exhaust gas purification catalyst is relatively low (i.e., catalyst warm-up is required), the intake air volume is increased compared to normal idle operation. This control, which increases the rotational speed of the internal combustion engine (engine rotational speed) during idle operation to increase the intake air volume for catalyst warm-up, is also called "catalyst early activation control." This is a time chart showing examples of changes in engine rotational speed in each cycle controlled by the control device of the internal combustion engine according to the first embodiment, for each engine rotational speed.This diagram schematically illustrates an internal combustion engine and a centrifugal clutch.This is a time chart showing an example of the changes in engine rotational speed and the rotational speed (transmission speed) of the output shaft of the centrifugal clutch, which has its input shaft connected to the internal combustion engine.This is a time chart showing an example of the changes in engine rotational speed controlled by the control device for the internal combustion engine according to the third embodiment, and the frictional force generated by the load generating device to act on the internal combustion engine.Figure 1 shows a magnified view of two changes in engine rotational speed. The present invention will be described below with reference to the drawings, based on embodiments. [First Embodiment] Figure 1 is a time chart showing an example of the change in engine rotational speed NE, which is the rotational speed of the internal combustion engine 2 according to the first embodiment, for each engine rotational speed NE. Figure 2 is a schematic diagram showing the internal combustion engine 2 and the centrifugal clutch 6. The internal combustion engine 2 is mounted as a power source in, for example, a saddle-type vehicle (not shown, and also referred to as a "mounted vehicle"). The internal combustion engine 2 is controlled by the ECU 1 (control unit, control unit, and control means). The rotation of the internal combustion engine 2 is transmitted to the drive wheels (not shown) of the vehicle via the centrifugal clutch 6. Figure 3 is a time chart showing an example of the changes in engine rotational speed NE and transmission rotational speed ND. Engine rotational speed NE is also the rotational speed of the input shaft in the centrifugal clutch 6. Transmission rotational speed ND is the rotational speed of the output shaft in the centrifugal clutch 6. The internal combustion engine 2 is a four-stroke, single-cylinder engine that repeats the intake stroke, compression stroke, combustion stroke (expansion stroke), and exhaust stroke. As shown in Figure 2, in the internal combustion engine 2, the reciprocating motion of the piston 21 is transmitted to the crankshaft 23 via the connecting rod 22, resulting in the rotation of the crankshaft 23. Let's explain the internal combustion engine 2 in more detail. The intake pipe 31 and intake port 32 form an intake path that introduces intake air (fresh air) into the combustion chamber 33 of the internal combustion engine 2. The intake valve 34 opens and closes the communication between the intake port 32 and the combustion chamber 33 according to the rotational position of the camshaft (not shown) of the internal combustion engine 2. A throttle valve 35 is provided in the intake manifold 31. The throttle valve 35 adjusts the opening of the intake manifold 31 (i.e., the throttle opening) according to the instructions of the ECU 1. A fuel injector 36 is provided in the intake port 32. The fuel injector 36 injects fuel into the intake port 32 according to the instructions of the ECU 1. Furthermore, a bypass passage 37 is provided in the intake manifold 31, bypassing the throttle valve 35. A bypass valve 38 is provided in the bypass passage 37. The bypass valve 38 adjusts the bypass valve opening degree Vb according to the instructions of the ECU 1. The bypass valve opening degree Vb is the opening degree of the bypass valve 38. A spark plug 39 is installed in the combustion chamber 33. The spark plug 39 ignites the air-fuel mixture in the combustion chamber 33 (i.e., the intake air containing fuel injected from the fuel injection valve 36) according to the instructions of the ECU 1. The exhaust port 41 and exhaust pipe 42 form an exhaust path for discharging exhaust gas (combustion gas) g