JP2024077777A - Internal Combustion Engine Systems - Google Patents

Abstract

[Problem] To start an engine quickly and stably with a simple configuration without using complex control. [Solution] At a specific crank angle where the overall center of gravity of at least one balance weight is located below the rotation axis, the center of a reference part in the rotation direction of a signal rotor is located rearward of a sensed position in the rotation direction and within an angular range of 45 degrees from the sensed position around the rotation axis of the signal rotor. [Selected Figure] Figure 1

Description

This disclosure relates to internal combustion engine systems.

A signal rotor that rotates integrally with the crankshaft is provided at the end of the crankshaft of the internal combustion engine. The signal rotor includes a number of teeth (protrusions) arranged at regular intervals in the circumferential direction on its outer periphery, and missing teeth (gaps) that are wider in the circumferential direction than the regular intervals in a portion of the outer periphery of the signal rotor. A crank angle sensor disposed near the signal rotor detects the teeth of the signal rotor that rotates with the crankshaft and outputs a pulse signal. An engine ECU determines the crank angle based on the pulse signal, and determines the ignition timing and fuel injection timing while determining the current stroke of the internal combustion engine.

JP 2004-232539 A

When starting the engine, if the time between when the crankshaft begins to rotate by the starter motor and when the first ignition occurs is long, the feeling when the vehicle starts moving is not good. Also, in the case of a parallel hybrid vehicle, if there is a delay in starting the engine, the switch from EV driving mode to HEV driving mode is delayed, and the feeling of changing driving modes is not good.

Therefore, one aspect of the present disclosure aims to start an engine quickly and stably with a simple configuration without using complex control.

An internal combustion engine system according to one aspect of the present disclosure includes an internal combustion engine including a horizontally extending crankshaft and at least one balance weight connected to the crankshaft, the at least one balance weight being unevenly arranged in the circumferential direction around the rotation axis of the crankshaft, a crank angle sensor, and a signal rotor that rotates in conjunction with the crankshaft, the signal rotor including a plurality of detection parts that are arranged at regular intervals in the circumferential direction on the outer periphery of the signal rotor and are detected by the crank angle sensor, and a reference part that has a width in the circumferential direction wider than the regular intervals in a part of the outer periphery of the signal rotor and is not detected by the crank angle sensor. The position of the part of the outer periphery of the signal rotor that faces the crank angle sensor is the detection position sensed by the crank angle sensor. At a specific crank angle where the overall center of gravity of the at least one balance weight is located below the rotation axis, the center of the reference part in the rotation direction of the signal rotor is located rearward of the sensed position in the rotation direction, and is located within an angular range of 45 degrees from the center of the sensed position around the rotation axis of the signal rotor.

An internal combustion engine system according to another aspect of the present disclosure includes an internal combustion engine including a plurality of cylinders including a first cylinder and a second cylinder, and a crankshaft connected to the plurality of cylinders, in which expansion strokes occur at irregular intervals, and the interval between adjacent ignition timings is the shortest interval between the ignition timing of the first cylinder and the ignition timing of the second cylinder, a crank angle sensor, and a signal rotor that rotates in conjunction with the crankshaft, the signal rotor including a plurality of detection parts that are arranged at regular intervals in the circumferential direction on the outer periphery of the signal rotor and are detected by the crank angle sensor, and a reference part that has a width in the circumferential direction wider than the regular intervals in a part of the outer periphery of the signal rotor and is not detected by the crank angle sensor. The position of the part of the outer periphery of the signal rotor that faces the crank angle sensor is the detection position detected by the crank angle sensor. The center of the reference part in the rotational direction of the signal rotor is located forward of the ignition timing part of the outer periphery that is at the sensed position at the ignition timing of the first cylinder, and is located within an angular range of 45 degrees from the center of the ignition timing part around the rotational axis.

This disclosure allows the engine to be started quickly and stably.

FIG. 1 is a block diagram of an internal combustion engine system according to a first embodiment. FIG. 2 is an enlarged view of the signal rotor and the crank angle sensor of FIG. FIG. 3 is a transition diagram showing the correspondence between the strokes of the internal combustion engine (single cylinder) of FIG. 1 and the signal rotor. FIG. 4 is a diagram showing another example of the arrangement of the reference portion in the signal rotor of FIG. FIG. 5 is a schematic diagram of an internal combustion engine (two-cylinder with a 360-degree crank) according to a second embodiment. FIG. 6A is a transition diagram showing the correspondence between the strokes of the internal combustion engine (two-cylinder with a 360-degree crank) of FIG. 5 and the signal rotor. FIG. 6B is a schematic diagram showing a continuation of FIG. 6A. FIG. 7A is a transition diagram showing the correspondence between strokes of an internal combustion engine (unequal explosion engine) according to the second embodiment and a signal rotor. FIG. 7B is a schematic diagram showing a continuation of FIG. 7A.

The following describes the embodiment with reference to the drawings.

First Embodiment
Fig. 1 is a block diagram of an internal combustion engine system 1 according to a first embodiment. As shown in Fig. 1, the internal combustion engine system 1 includes an internal combustion engine 2, a crank angle sensor 3, a signal rotor 4, an electric motor 5, and a controller 6. The internal combustion engine system 1 is mounted as a driving source in a vehicle such as a motorcycle, a three-wheeled motor vehicle, an off-road four-wheeled vehicle, or the like.

The internal combustion engine 2 is, for example, a single-cylinder engine. The internal combustion engine 2 has a cylinder 10. A piston 11 is housed in the cylinder 10 so that it can reciprocate. The piston 11 is connected to a crankshaft 15 via a connecting rod 12, a crank pin 13, and a crank arm 14. The crankshaft 15 extends in the horizontal direction. A balance weight 16 is connected to the crankshaft 15. The balance weight 16 is unevenly arranged in the circumferential direction around the rotation axis X of the crankshaft 15. The overall center of gravity G of the balance weight 16 is offset from the rotation axis X.

The internal combustion engine 2 is, for example, a four-stroke engine. A combustion chamber 17 is defined above the piston 11 within the cylinder 10. The internal combustion engine 2 has an intake port 18 that communicates with the combustion chamber 17, and an exhaust port 19 that communicates with the combustion chamber 17. An intake valve 20 is disposed in the intake port 18, and an exhaust valve 21 is disposed in the exhaust port 19. A fuel injector 22 that injects fuel into the intake passage is provided in the intake port 18. An intake pressure sensor 23 that detects the pressure of the intake air flowing through the intake passage is provided in the intake port 18. The internal combustion engine 2 is provided with an ignition plug 24 for igniting the mixture in the combustion chamber 17.

A signal rotor 4 is fixed to the end of the crankshaft 15. The crank angle sensor 3 faces the signal rotor 4 in a direction perpendicular to the rotation axis X. Details of the crank angle sensor 3 and the signal rotor 4 will be described later. The electric motor 5 is mechanically connected to the crankshaft 15 so as to be able to drive the crankshaft 15. The drive shaft of the electric motor 5 is connected to the crankshaft 15 via a gear mechanism, a belt and pulley mechanism, or a chain and sprocket mechanism.

The controller 6 controls the internal combustion engine 2 and the electric motor 5. The controller 6 includes a processor 31, a system memory 32, and a storage memory 33. The processor 31 is, for example, a central processing unit. The system memory 32 is, for example, a RAM. The storage memory 33 is an example of a computer-readable medium, and is a non-transitory, tangible medium. The storage memory 33 may include a ROM. The storage memory 33 may include a hard disk, a flash memory, or a combination thereof. The storage memory 33 stores a program. The configuration in which the processor 31 executes the program read into the system memory 32 is an example of a processing circuit.

The controller 6 determines the stroke (intake, compression, expansion, exhaust) during operation of the internal combustion engine 2 based on the crank angle detected by the crank angle sensor 3 and the intake pressure detected by the intake pressure sensor 23. The intake pressure is an example of a physical quantity that changes depending on the state of the combustion chamber 17 for each stroke. The controller 6 controls the operation timing of the fuel injector 22 and the spark plug 24 based on the determined stroke.

Figure 2 is an enlarged view of the signal rotor 4 and crank angle sensor 3 of Figure 1. As shown in Figure 2, the signal rotor 4 is fixed to the crankshaft 15 so as to rotate integrally with the crankshaft 15 around the rotation axis X of the crankshaft 15. The outer periphery of the signal rotor 4 includes a plurality of detectable parts 4a arranged at regular intervals in the circumferential direction C, and a reference part 4b having a width wider in the circumferential direction C than the regular intervals. The detectable parts 4a are parts that are detected by the detection part 3a of the crank angle sensor 3. The reference parts 4b have a width wider in the circumferential direction C than the regular intervals. The reference parts 4b are parts that are not detected by the crank angle sensor 3.

For example, the crank angle sensor 3 is an electromagnetic pickup sensor, and the signal rotor 4 is made of metal. The detected portion 4a is a protrusion (tooth) that protrudes radially outward from the outer periphery of the signal rotor 4. The gap 4c between two adjacent detected portions 4a is a portion that is not detected by the detection portion 3a of the crank angle sensor 3. The width of the reference portion 4b in the circumferential direction C is greater than the width of the gap 4c in the circumferential direction C. Specifically, the reference portion 4b is a wide gap (missing tooth) formed by missing one of multiple protrusions that are arranged at equal intervals in the circumferential direction C around the entire circumference of the outer periphery of the signal rotor 4.

The position of the portion of the outer periphery of the signal rotor 4 that faces the detection portion 3a of the crank angle sensor 3 is the sensed position P that is sensed by the crank angle sensor 3. Because the width of the gap 4c in the circumferential direction C and the width of the reference portion 4b in the circumferential direction C are different from each other, the controller 6 can recognize the reference portion 4b separately from the gap 4c based on the detection signal of the crank angle sensor 3. The controller 6 detects the base point angle of the crank angle by recognizing that the reference portion 4b is at the sensed position P. The controller 6 calculates the amount of angular displacement from the base point angle by counting the detected portions 4a that are detected after the detection of the reference portion 4b.

Figure 3 is a transition diagram showing the correspondence between the strokes of the internal combustion engine 2 (single cylinder) in Figure 1 and the signal rotor 4. As shown in Figure 3, the internal combustion engine 2 repeats a cycle consisting of the strokes of exhaust, intake, compression, and expansion. In the example of Figure 3, the posture of the balance weight 16 in the crank angle range from "(1) exhaust" to "(8) intake" is the same as the posture of the balance weight 16 in the crank angle range from "(9) compression" to "(16) expansion". In particular, the crank angle range from "(3) exhaust" to "(5) intake" and the crank angle range from "(11) compression" to "(13) expansion" are ranges in which the center of gravity G of the balance weight 16 is located below the rotation axis X of the crankshaft 15. This crank angle range is referred to as a specific crank angle range, and one crank angle in the specific crank angle range is referred to as a specific crank angle.

At least one specific crank angle in the specific crank angle range, the center of the reference portion 4b in the rotational direction of the signal rotor 4 is located rearward of the sensed position P in the rotational direction, and is located within an angular range of 45 degrees from the center of the sensed position P in the circumferential direction C around the rotation axis X. Here, "rearward of the sensed position P in the rotational direction" means an angular region within a range of 180 degrees in the reverse direction of rotation of the signal rotor 4 with the center of the sensed position P as the reference. In the example of FIG. 3, the center of the reference portion 4b in the rotational direction of the signal rotor 4 is located rearward of the sensed position P in the rotational direction throughout the specific crank angle range.

The portion of the outer periphery of the signal rotor 4 that is at the sensed position P at the ignition timing when the internal combustion engine 2 is started is referred to as the ignition timing portion 4d. The reference portion 4b of the signal rotor 4 is disposed at a portion of the outer periphery of the signal rotor 4 that is different from the ignition timing portion 4d. When the ignition timing changes depending on the operating conditions of the internal combustion engine 2, it is preferable that the reference portion 4b of the signal rotor 4 is disposed at a portion of the outer periphery of the signal rotor 4 that is different from each portion that is at the sensed position P at each possible time that can be the ignition timing.

Because the balance weights 16 are unevenly positioned in the circumferential direction C around the rotation axis X, there is a high possibility that the internal combustion engine 2 will stop with the center of gravity G of the balance weights 16 positioned below the rotation axis X (each state surrounded by a two-dot chain line in FIG. 3). In this embodiment, the reference portion 4b of the signal rotor 4 is positioned as described above, so that when the internal combustion engine 2 is started, the reference portion 4b of the signal rotor 4 is quickly detected by the crank angle sensor 3. Therefore, when the internal combustion engine 2 is started, the controller 6 can quickly grasp the current crank angle, and the internal combustion engine 2 can be started quickly and stably.

The controller 6 may control the electric motor 5 so that the crank angle of the internal combustion engine 2 becomes the specific crank angle when the internal combustion engine 2 that was running is stopped. That is, the controller 6 may control the electric motor 5 so that when the internal combustion engine 2 is stopped, the center of the reference portion 4b in the rotational direction of the signal rotor 4 is positioned rearward of the sensed position P in the rotational direction and within an angular range of 45 degrees from the center of the sensed position P. This further increases the possibility that the reference portion 4b of the signal rotor 4 will be promptly detected by the crank angle sensor 3 when the internal combustion engine 2 is started.

The position of the reference portion 4b of the signal rotor 4 is determined by referring to the posture of the balance weight 16 regardless of the orientation of the cylinder 10, so the cylinder 10 does not have to be arranged to extend vertically. For example, the cylinder 10 may extend at an angle to the vertical direction, or may extend horizontally.

Figure 4 is a diagram showing another example of the arrangement of the reference portion 4b in the signal rotor 4 in Figure 3. In the example of Figure 4, ignition occurs at "(12) compression". At the ignition crank angle corresponding to the ignition timing at the start of the internal combustion engine 2, the center of the reference portion 4b in the rotational direction of the signal rotor 4 is located forward of the sensed position P in the rotational direction. Here, "forward of the sensed position P in the rotational direction" means an angular region within a range of 180 degrees in the rotational direction of the signal rotor 4, i.e., the forward rotation direction, based on the sensed position P. And, at the ignition crank angle, the center of the reference portion 4b in the rotational direction of the signal rotor 4 is located within an angular range of 45 degrees from the center of the sensed position P in the circumferential direction C around the rotation axis X.

With this configuration, the ignition timing arrives promptly after the crank angle sensor 3 detects the reference portion 4b of the signal rotor 4. Therefore, when starting the internal combustion engine 2, the ignition timing arrives in a short time, allowing the internal combustion engine 2 to start quickly.

In the example of FIG. 4, at least one specific crank angle in the specific crank angle range (for example, "(3) exhaust" and "(11) compression"), the center of the reference portion 4b in the rotational direction of the signal rotor 4 is located rearward of the sensed position P in the rotational direction and within an angular range of 45 degrees from the center of the sensed position P.

In addition, since the position of the reference portion 4b of the signal rotor 4 is determined by referring to the posture of the balance weight 16 that is unevenly arranged around the rotation axis X, the number of cylinders is not limited to one or two. As long as the balance weight 16 as a whole is unevenly arranged around the rotation axis X, the number of cylinders may be three or more.

Second Embodiment
FIG. 5 is a schematic diagram of an internal combustion engine 102 (two-cylinder with a 360-degree crank) according to the second embodiment. The same reference numerals are used to designate the same components as those in the first embodiment, and the description thereof will be omitted. As shown in FIG. 5, the internal combustion engine 102 is a two-cylinder engine with a 360-degree crank. That is, the arrangement angle of the crank pin 13 around the crankshaft 15 in the first cylinder 10A is the same as the arrangement angle of the crank pin 13 around the crankshaft 15 in the second cylinder 10B. The first cylinder 10A and the second cylinder 10B may perform strokes shifted by 360 degrees from each other in crank angle, or may perform the same stroke at the same time.

Figure 6A is a transition diagram showing the correspondence between the strokes of the internal combustion engine 102 (two-cylinder with a 360-degree crank) in Figure 5 and the signal rotor 4. Figure 6B is a schematic diagram showing a continuation of Figure 6A. As shown in Figures 6A and B, the basic concept of the two-cylinder engine 102 with a 360-degree crank is the same as that of the single-cylinder engine 2. The first cylinder 10A and the second cylinder 10B perform strokes with a 360-degree shift in crank angle. In the example of Figures 6A and B, the crank angle range from "(1) Exhaust" to "(12) Expansion" of the first cylinder 10A and the crank angle range from "(1) Compression" to "(12) Intake" of the second cylinder 10B are the same.

In the first crank angle range, which is the range from "(2) Exhaust" to "(4) Intake" of the first cylinder 10A and the range from "(2) Compression" to "(4) Expansion" of the second cylinder 10B, and the second crank angle range, which is the range from "(8) Compression" to "(10) Expansion" of the first cylinder 10A and the range from "(8) Exhaust" to "(10) Intake" of the second cylinder 10B, the center of gravity G of the entire balance weight 16 is located below the rotation axis X of the crankshaft 15. The first crank angle range and the second crank angle range are referred to as specific crank angle ranges, and one crank angle in the specific crank angle range is referred to as a specific crank angle.

At least one specific crank angle in the specific crank angle range, the center of the reference portion 4b in the rotational direction of the signal rotor 4 is located rearward of the sensed position P in the rotational direction, and is located within an angular range of 45 degrees from the center of the sensed position P in the circumferential direction C about the rotation axis X. In the example of Figures 6A and B, the center of the reference portion 4b in the rotational direction of the signal rotor 4 is located rearward of the center of the sensed position P in the rotational direction throughout the specific crank angle range.

Because the balance weights 16 are unevenly arranged in the circumferential direction C around the rotation axis X, there is a high possibility that the internal combustion engine 102 will stop with the center of gravity G of the balance weights 16 positioned below the rotation axis X (each state surrounded by a two-dot chain line in Figures 6A and 6B). In this embodiment, the reference portion 4b of the signal rotor 4 is arranged as described above, so that the reference portion 4b of the signal rotor 4 is quickly detected by the crank angle sensor 3 when the internal combustion engine 102 is started. Therefore, when the internal combustion engine 102 is started, the controller 6 can quickly grasp the current crank angle, and the internal combustion engine 2 can be started quickly and stably. Note that other configurations are the same as those of the first embodiment described above, so description thereof will be omitted.

Third Embodiment
FIG. 7A is a transition diagram showing the correspondence between the strokes of the internal combustion engine 202 (unequal-interval explosion engine) according to the third embodiment and the signal rotor 4. FIG. 7B is a schematic diagram showing a continuation of FIG. 7A. Note that the same reference numerals are used to designate the same components as in the first embodiment, and the description thereof will be omitted. As shown in FIGS. 7A and 7B, the internal combustion engine 202 is an unequal-interval explosion engine. That is, the internal combustion engine 202 generates an expansion stroke (explosion stroke) at unequal intervals in the entire first cylinder 10C and the second cylinder 10D. In this embodiment, the interval between the adjacent ignition timings is the minimum interval between the ignition timing of the first cylinder 10C and the ignition timing of the second cylinder 10D. That is, the interval between the ignition timing of the first cylinder 10C and the ignition timing of the second cylinder 10D is smaller than the interval between the ignition timing of the second cylinder 10D and the ignition timing of the first cylinder 10C.

The center of the reference portion 4b in the rotational direction of the signal rotor 4 is located forward of the ignition timing portion 4d at the time of engine start, and is located within an angular range of 45 degrees from the ignition timing portion 4d around the rotation axis X of the signal rotor 4. Here, "foreward of the ignition timing portion 4d in the rotational direction" means an angular region within a range of 180 degrees in the rotational direction of the signal rotor 4, i.e., the forward rotation direction, based on the center of the ignition timing portion 4d.

As a result, the ignition timing of the first cylinder 10C arrives a short time after the crank angle sensor 3 detects the reference portion 4b of the signal rotor 4, and the ignition timing of the second cylinder 10D arrives a short time thereafter. This allows the internal combustion engine 202 to start quickly and stably. Note that other configurations are the same as those of the first embodiment described above, so a description thereof will be omitted.

As described above, the above embodiment has been described as an example of the technology disclosed in this application. However, the technology in this disclosure is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate. In addition, it is also possible to combine the components described in the above embodiment to create a new embodiment. For example, a portion of the configuration or method in one embodiment may be applied to another embodiment, and a portion of the configuration in an embodiment can be separated from the other configurations in that embodiment and arbitrarily extracted. In addition, the components described in the attached drawings and detailed description include not only components essential for solving the problem, but also components that are not essential for solving the problem in order to illustrate the technology.

The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general purpose processors, special purpose processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits, and/or combinations thereof, configured or programmed to perform the disclosed functions. Processors are considered processing circuits or circuits because they include transistors and other circuits. In this disclosure, a circuit, unit, or means is hardware that performs the recited functions or hardware that is programmed to perform the recited functions. The hardware may be hardware disclosed herein or other known hardware that is programmed or configured to perform the recited functions. When the hardware is a processor, which is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and/or the processor.

Each of the following sections discloses a preferred embodiment.

[Item 1]
an internal combustion engine including a crankshaft extending in a horizontal direction and at least one balance weight connected to the crankshaft, the at least one balance weight being unevenly disposed in a circumferential direction around a rotation axis of the crankshaft;
A crank angle sensor;
a signal rotor that rotates in conjunction with the crankshaft, the signal rotor including a plurality of detectable portions that are arranged at regular intervals in the circumferential direction on an outer periphery of the signal rotor and that are detected by the crank angle sensor, and a reference portion that has a width in the circumferential direction wider than the regular intervals in a part of the outer periphery of the signal rotor and that is not detected by the crank angle sensor,
a position of a portion of the outer circumferential portion of the signal rotor that faces the crank angle sensor is a sensed position that is sensed by the crank angle sensor,
An internal combustion engine system, wherein at a specific crank angle where the overall center of gravity of the at least one balance weight is located below the rotational axis, the center of the reference part in the rotational direction of the signal rotor is located rearward of the sensed position in the rotational direction and is located within an angular range of 45 degrees from the center of the sensed position around the rotational axis of the signal rotor.

With this configuration, at least one balance weight is unevenly positioned in the circumferential direction around the rotation axis, so that the internal combustion engine is likely to stop at a specific crank angle where the center of gravity of the balance weight as a whole is located below the rotation axis. The center of the rotation direction of the reference part of the signal rotor is located rearward of the sensed position in the rotation direction at the specific crank angle and within an angular range of 45 degrees around the rotation axis from the sensed position. Therefore, when the engine is started, the reference part of the signal rotor is quickly detected by the crank angle sensor. Therefore, the current crank angle is quickly determined when the engine is started, and the engine can be started quickly and stably.

[Item 2]
2. The internal combustion engine system according to claim 1, wherein, at an ignition crank angle corresponding to an ignition timing at a start of the internal combustion engine, a center of the reference portion in the rotational direction of the signal rotor is positioned forward of the sensed position in the rotational direction and within an angular range of 45 degrees around the rotation axis from the center of the sensed position.

With this configuration, the ignition timing occurs quickly after the crank angle sensor detects the reference portion of the signal rotor. Therefore, when the engine is started, the ignition timing occurs in a short time, allowing the engine to start quickly.

[Item 3]
3. The internal combustion engine system according to claim 1 or 2, wherein the internal combustion engine is a single cylinder engine or a two-cylinder engine with a 360-degree crank.

With this configuration, in an engine in which at least one balance weight is unevenly positioned in the circumferential direction around the rotation axis, proper positioning of the reference portion of the signal rotor allows for rapid engine start-up.

[Item 4]
an electric motor connectable to the crankshaft;
a processing circuit for controlling the internal combustion engine and the electric motor;
4. The internal combustion engine system according to any one of claims 1 to 3, wherein the processing circuit controls the electric motor so that a crank angle of the internal combustion engine becomes the specific crank angle when the internal combustion engine is stopped.

This configuration further increases the likelihood that the reference portion of the signal rotor will be quickly detected by the crank angle sensor when the engine is started.

[Item 5]
An internal combustion engine including a plurality of cylinders including a first cylinder and a second cylinder, and a crankshaft connected to the plurality of cylinders, wherein expansion strokes are generated at irregular intervals, and among intervals between adjacent ignition timings, an interval between the ignition timing of the first cylinder and the ignition timing of the second cylinder is a minimum interval;
A crank angle sensor;
a signal rotor that rotates in conjunction with the crankshaft, the signal rotor including a plurality of detectable portions that are arranged at regular intervals in the circumferential direction on an outer periphery of the signal rotor and that are detected by the crank angle sensor, and a reference portion that has a width in the circumferential direction wider than the regular intervals in a part of the outer periphery of the signal rotor and that is not detected by the crank angle sensor,
a position of a portion of the outer circumferential portion of the signal rotor that faces the crank angle sensor is a sensed position that is sensed by the crank angle sensor,
an internal combustion engine system, wherein the center of the reference portion in the rotational direction of the signal rotor is positioned forward in the rotational direction of an ignition timing portion of the outer circumferential portion that is at the sensed position at the ignition timing of the first cylinder, and is positioned within an angular range of 45 degrees from the center of the ignition timing portion around the rotational axis of the signal rotor.

With this configuration, the ignition timing for the first cylinder arrives a short time after the crank angle sensor detects the reference portion of the signal rotor, and the ignition timing for the second cylinder arrives a short time after that. This allows the engine to start quickly and stably.

REFERENCE SIGNS LIST 1 Internal combustion engine system 2, 102, 202 Internal combustion engine 3 Crank angle sensor 4 Signal rotor 4a Detected portion 4b Reference portion 4d Ignition timing portion 5 Electric motor 6 Controller 10 Cylinder 10C First cylinder 10D Second cylinder 15 Crankshaft 16 Balance weight G Center of gravity P Detected position X Rotation axis

Claims (5)

an internal combustion engine including a crankshaft extending in a horizontal direction and at least one balance weight connected to the crankshaft, the at least one balance weight being unevenly disposed in a circumferential direction around a rotation axis of the crankshaft;
A crank angle sensor;
a signal rotor that rotates in conjunction with the crankshaft, the signal rotor including a plurality of detectable portions that are arranged at regular intervals in the circumferential direction on an outer periphery of the signal rotor and that are detected by the crank angle sensor, and a reference portion that has a width in the circumferential direction wider than the regular intervals in a part of the outer periphery of the signal rotor and that is not detected by the crank angle sensor,
a position of a portion of the outer circumferential portion of the signal rotor that faces the crank angle sensor is a sensed position that is sensed by the crank angle sensor,
An internal combustion engine system, wherein at a specific crank angle where the overall center of gravity of the at least one balance weight is located below the rotational axis, the center of the reference part in the rotational direction of the signal rotor is located rearward of the sensed position in the rotational direction and is located within an angular range of 45 degrees around the rotational axis from the center of the sensed position. The internal combustion engine system according to claim 1, wherein, at an ignition crank angle corresponding to the ignition timing at the start of the internal combustion engine, the center of the reference part in the rotational direction of the signal rotor is disposed forward of the sensed position in the rotational direction and within an angular range of 45 degrees around the rotation axis from the center of the sensed position. The internal combustion engine system according to claim 1 or 2, wherein the internal combustion engine is a single cylinder engine or a two cylinder engine with a 360 degree crank. an electric motor connectable to the crankshaft;
a processing circuit for controlling the internal combustion engine and the electric motor;
3. The internal combustion engine system according to claim 1, wherein the processing circuit controls the electric motor so that a crank angle of the internal combustion engine is at the specific crank angle when the internal combustion engine is stopped. An internal combustion engine including a plurality of cylinders including a first cylinder and a second cylinder, and a crankshaft connected to the plurality of cylinders, wherein expansion strokes are generated at irregular intervals, and among intervals between adjacent ignition timings, an interval between the ignition timing of the first cylinder and the ignition timing of the second cylinder is a minimum interval;
A crank angle sensor;
a signal rotor that rotates in conjunction with the crankshaft, the signal rotor including a plurality of detectable portions that are arranged at regular intervals in the circumferential direction on an outer periphery of the signal rotor and that are detected by the crank angle sensor, and a reference portion that has a width in the circumferential direction wider than the regular intervals in a part of the outer periphery of the signal rotor and that is not detected by the crank angle sensor,
a position of a portion of the outer circumferential portion of the signal rotor that faces the crank angle sensor is a sensed position that is sensed by the crank angle sensor,
an internal combustion engine system, wherein the center of the reference portion in the rotational direction of the signal rotor is positioned forward in the rotational direction of an ignition timing portion of the outer circumferential portion that is at the sensed position at the ignition timing of the first cylinder, and is positioned within an angular range of 45 degrees from the center of the ignition timing portion around the rotational axis of the signal rotor.

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