JP2021025511A - Engine and vehicle - Google Patents

Abstract

To provide an engine which achieves vehicle control suitable for variations of negative pressures generated in cylinders.SOLUTION: An engine (10) includes: an engine body having a front cylinder 13 and a rear cylinder 14; a first throttle valve 34 located at the intake side of the front cylinder; a second throttle valve 44 located at the intake side of the rear cylinder; and an ECU 50 which controls opening/closing operation of the first and second throttle valves. A negative pressure in the front cylinder is larger than a negative pressure in the rear cylinder. The ECU causes the first throttle valve at the upstream of the front cylinder to close while leaving a gap larger than that of the second throttle valve at the upstream of the rear cylinder when the first and second throttle valves close.SELECTED DRAWING: Figure 4

Description

The present invention relates to an engine and a vehicle.

As an engine mounted on a vehicle such as a saddle-type vehicle, an engine having an exhaust port separated, such as a V-type engine or a horizontally opposed engine, is known (see, for example, Patent Document 1). In such an engine, a pair of front and rear cylinders are tilted in opposite directions, and a throttle valve is provided for each cylinder. Each throttle valve is attached to the intake pipe, and by opening and closing according to the operation of the accelerator grip, the amount of intake air sent from the intake pipe to each cylinder is adjusted. The engine output is controlled by changing the combustion efficiency of each cylinder according to the intake amount of each cylinder.

JP-A-2009-851112

Since the cylinders of the above engine are separated from each other, the negative pressure varies among the plurality of cylinders. If the throttle valve is closed during deceleration, excessive negative pressure may be generated in some cylinders, and the engine oil adhering to the inner wall of this cylinder is sucked into the combustion chamber, increasing the consumption of engine oil. To do. On the other hand, if the throttle valve is suppressed from closing during deceleration, it is possible to suppress the generation of excessive negative pressure in some cylinders, but it is not possible to obtain sufficient braking force for the engine brake due to the negative pressure. ..

The present invention has been made in view of the above points, and an object of the present invention is to provide an engine and a vehicle capable of realizing vehicle control suitable for variations in negative pressure generated in a plurality of cylinders.

The engine of one aspect of the present invention includes an engine body having a plurality of cylinders, a plurality of throttle valves located on the intake side of the plurality of cylinders, and a control unit for controlling the opening / closing operation of the plurality of throttle valves. In the engine provided, the negative pressure in some cylinders of the plurality of cylinders is larger than the negative pressure in other cylinders, and the control unit performs the above-mentioned one when the plurality of throttle valves are closed. The above problem is solved by closing a part of the throttle valves upstream of the cylinder of the part with a larger gap than the other throttle valves upstream of the other cylinders.

According to the engine of one aspect of the present invention, when the throttle valve is closed such as during deceleration, a part of the throttle valve upstream of some cylinders having a large internal negative pressure is replaced with another part of the throttle valve upstream of another cylinder. Close the valve leaving a larger gap than the throttle valve. Therefore, in some cylinders, suction of engine oil into the combustion chamber due to excessive negative pressure is prevented, and in other cylinders, sufficient braking force of the engine brake due to negative pressure can be obtained. Therefore, it is possible to achieve both the suppression of engine oil consumption and the braking effect of the engine brake.

It is a perspective view of the engine of this embodiment. It is a side view of the engine of this embodiment. It is a bottom view of the engine of this embodiment. It is a schematic diagram of the engine of this embodiment. It is a perspective view of the exhaust device of this Example. It is a figure which shows the relationship between the opening degree of the throttle valve and the vehicle speed of this Example. It is a figure which shows the relationship between the opening degree of the throttle valve of a comparative example, and a vehicle speed. It is a flowchart of valve control of this Example. It is a flowchart of valve control of another embodiment.

In the engine of one aspect of the present invention, the intake amount of each cylinder is adjusted by a plurality of throttle valves on the intake side of the plurality of cylinders. Further, the negative pressure in some of the plurality of cylinders is larger than the negative pressure in the other cylinders, and the negative pressure varies among the plurality of cylinders. When the throttle valve is closed, such as when decelerating, some throttle valves upstream of some cylinders with large internal negative pressure leave a larger gap than other throttle valves upstream of other cylinders. To do. In some cylinders, excessive negative pressure prevents the engine oil from being sucked into the combustion chamber, and in other cylinders, the negative pressure provides sufficient braking force for the engine brake, reducing engine oil consumption and reducing engine braking. The braking effect is compatible.

Hereinafter, this embodiment will be described in detail with reference to the accompanying drawings. Here, an example in which the engine of this embodiment is applied to a motorcycle as a saddle-type vehicle will be described, but the application target is not limited to this. For example, the engine may be applied to other saddle-type vehicles such as buggy type tricycles. Further, in the following figures, the front of the vehicle is indicated by an arrow FR, the rear of the vehicle is indicated by an arrow RE, the left side of the vehicle is indicated by an arrow L, and the right side of the vehicle is indicated by an arrow R. FIG. 1 is a perspective view of the engine of this embodiment. FIG. 2 is a side view of the engine of this embodiment. FIG. 3 is a bottom view of the engine of this embodiment.

As shown in FIGS. 1 to 3, the engine 10 is a V-type engine that explodes at irregular intervals, and the engine body 11 in which the front cylinder 13 and the rear cylinder 14 are arranged in a V shape on the crankcase 12 is provided. Have. The front cylinder 13 is tilted toward the front of the vehicle, and is formed by mounting the cylinder head 22 and the head cover 23 on the cylinder block 21 projecting from the crankcase 12. Similarly, the rear cylinder 14 is inclined to the rear of the vehicle, and is formed by mounting the cylinder head 26 and the head cover 27 on the cylinder block 25 projecting from the crankcase 12.

An intake port 31 (see FIG. 4) is opened on the rear surface of the front cylinder 13, and a first intake pipe 32 is connected to the intake port 31. An intake port 41 (see FIG. 4) is opened on the front surface of the rear cylinder 14, and a second intake pipe 42 is connected to the intake port 41. The first and second intake pipes 32 and 42 extend upward from the pair of front and rear cylinders 13 and 14, respectively, and are connected to the lower part of the air cleaner 15 that filters the outside air. A first throttle body 33 for the front cylinder 13 is provided in the middle portion of the first intake pipe 32, and a second throttle body 43 for the rear cylinder 14 is provided in the middle portion of the second intake pipe 42. It is provided.

The first throttle body 33 is provided with a first throttle valve 34 (see FIG. 4) for adjusting the intake amount of the front cylinder 13, and the second throttle body 43 adjusts the intake amount of the rear cylinder 14. A second throttle valve 44 is provided (see FIG. 4). The first and second throttle bodies 33 and 43 are electronic throttle bodies, and have motors 35 and 45 (see FIG. 4) for opening and closing the first and second throttle valves 34 and 44. By having the motors 35 and 45 individually for the first and second throttle bodies 33 and 43, it is possible to independently adjust the intake amount for each cylinder of the first and second throttle valves 34 and 44. is there.

An exhaust port 37 (see FIG. 4) is opened on the front surface of the front cylinder 13, and a first exhaust pipe 38 is connected to the exhaust port 37. An exhaust port 47 (see FIG. 4) is opened on the rear surface of the rear cylinder 14, and a second exhaust pipe 48 is connected to the exhaust port 47. The first and second exhaust pipes 38 and 48 extend downward from the pair of front and rear cylinders 13 and 14, respectively, and are connected to a catalyst device 16 that purifies air pollutants in the exhaust gas. The catalyst device 16 is installed at the rear of the vehicle, below the engine 10 and behind the vehicle by the center C of the crankshaft in the crankcase 12.

A second exhaust pipe 48 rather than the first exhaust pipe 38 is connected to the catalyst device 16 below the engine 10 through a complicated path. Therefore, the pipe length from the outlet of the exhaust ports 37 and 47 to the inlet of the catalyst device 16 differs between the first exhaust pipe 38 and the second exhaust pipe 48, and the second exhaust pipe 48 connected to the rear cylinder 14 The length of the first exhaust pipe 38 connected to the front cylinder 13 is shorter than the length of the pipe. The details of the pipe shapes of the first and second exhaust pipes 38 and 48 will be described later. Further, the first and second exhaust pipes 38 and 48 are connected to the catalyst device 16 via the collecting pipe 17, and a muffler 18 for muting the exhaust sound is provided on the downstream side of the catalyst device 16. There is.

In the engine 10 configured in this way, air flows from the air cleaner 15 toward the front cylinder 13 and the rear cylinder 14 via the first and second intake pipes 32 and 42. The first and second throttle valves 34 and 44 adjust the intake amount for the front cylinder 13 and the rear cylinder 14, and the fuel supply device (not shown) mixes the fuel with the air into the cylinders 13 and 14. The air-fuel mixture is sent. The exhaust gas after combustion flows from the cylinders 13 and 14 through the first and second exhaust pipes 38 and 48 into the catalyst device 16, and is exhausted from the silencer 18 after the air pollutants are purified by the catalyst device 16.

In the engine 10 that explodes at irregular intervals, the combustion states of the front and rear cylinders 13 and 14 may change, and in particular, the lengths of the first and second exhaust pipes 38 and 48 of the front and rear cylinders 13 and 14 are different. And the tendency to change the combustion state becomes stronger. This is recognized by the user as a driving feeling peculiar to the engine, which is an advantage for a motorcycle. The difference in the combustion state of the front and rear cylinders 13 and 14 represents the difference in the intake amount of the front and rear cylinders 13 and 14. Therefore, when the motorcycle decelerates, the negative pressure generated in the front and rear cylinders 13 and 14 varies.

When the first and second throttle valves 34 and 44 are closed and the vehicle speed drops during deceleration of the motorcycle, negative pressure is generated in the front and rear cylinders 13 and 14. Since an exhaust pipe shorter than the rear cylinder 14 is connected to the front cylinder 13, the exhaust efficiency of the front cylinder 13 is good due to the pulsation generated in the intake / exhaust process when the throttle opening is closed and the vehicle decelerates. The negative pressure in the front cylinder 13 is larger than the negative pressure in the side cylinder 14. Therefore, there is a problem that the engine oil flows back to the combustion chamber side from the abutment gap of the piston ring 64 (see FIG. 4) due to the negative pressure in the front cylinder 13. On the other hand, the negative pressure in the front and rear cylinders 13 and 14 becomes a pumping loss and acts as an engine brake.

Therefore, in this embodiment, paying attention to the fact that the front cylinder 13 has a larger negative pressure than the rear cylinder 14, the first throttle valve 34 upstream of the front cylinder 13 is moved upstream of the rear cylinder 14 when the motorcycle decelerates. The valve is closed leaving a gap larger than that of the second throttle valve 44. As a result, the generation of excessive negative pressure in the front cylinder 13 is suppressed, and the suction of engine oil into the combustion chamber due to the negative pressure is prevented. It is possible to achieve both suppression of engine oil consumption and braking effect of the engine brake when decelerating a motorcycle, and to realize vehicle control suitable for variations in negative pressure generated in the front and rear cylinders 13 and 14.

Hereinafter, the detailed configuration of the engine of this embodiment will be described with reference to FIGS. 4 and 5. FIG. 4 is a schematic view of the engine of this embodiment. FIG. 5 is a perspective view of the exhaust device of this embodiment.

As shown in FIG. 4, on the intake side of the front cylinder 13, an intake valve 61 that opens and closes the intake port 31 so as to take in the air-fuel mixture into the cylinder is provided. On the exhaust side of the front cylinder 13, an exhaust valve 62 that opens and closes the exhaust port 37 so as to exhaust the exhaust gas from the inside of the cylinder is provided. A piston 63 is housed in the cylinder of the front cylinder 13 so as to be reciprocating, and the piston 63 is equipped with a piston ring 64 that seals a gap between the outer surface of the piston and the inner wall surface of the cylinder. Further, an ignition plug 65 for igniting the air-fuel mixture in the combustion chamber is abutted at the upper portion of the front cylinder 13.

The rear cylinder 14 is formed in the same manner as the front cylinder 13. That is, the rear cylinder 14 is provided with an intake valve 71 that opens and closes the intake port 41, an exhaust valve 72 that opens and closes the exhaust port 47, and a piston 73 housed in the cylinder. A spark plug 75 that ignites the air-fuel mixture in the combustion chamber is abutted at the upper portion of the rear cylinder 14. Unequally spaced explosions occur in the front cylinder 13 and the rear cylinder 14, and the negative pressure in the cylinder varies due to the difference in the combustion state (intake amount) between the front cylinder 13 and the rear cylinder 14.

An air cleaner 15 is connected to the intake port 31 of the front cylinder 13 via a first intake pipe 32, and a first throttle body 33 is provided in the middle of the first intake pipe 32. The first throttle body 33 is provided with a first throttle valve 34 that opens and closes in response to an operation of the accelerator grip 52. The amount of intake air sent into the front cylinder 13 is adjusted according to the opening degree of the first throttle valve 34. Further, the first throttle body 33 is provided with a motor 35 connected to the first throttle valve 34 and a throttle sensor 36 for detecting the opening degree of the first throttle valve 34. Further, the first intake pipe 32 is provided with an intake pressure sensor 39 such as a boost sensor that detects the intake pressure.

Similarly, an air cleaner 15 is connected to the intake port 41 of the rear cylinder 14 via a second intake pipe 42, and a second throttle body 43 is provided in the middle of the second intake pipe 42. The second throttle body 43 is provided with a second throttle valve 44 that opens and closes in response to an operation of the accelerator grip 52. The amount of intake air sent into the rear cylinder 14 is adjusted according to the opening degree of the second throttle valve 44. Further, the second throttle body 43 is provided with a motor 45 connected to the second throttle valve 44 and a throttle sensor 46 for detecting the opening degree of the second throttle valve 44.

A first exhaust pipe 38 is connected to the exhaust port 37 of the front cylinder 13, and a second exhaust pipe 48 is connected to the exhaust port 47 of the rear cylinder 14. The first and second exhaust pipes 38 and 48 are grouped together by a collecting pipe 17 and connected to the catalyst device 16, and a silencer 18 is connected to the downstream side of the catalyst device 16. The catalyst device 16 purifies air pollutants such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) contained in the exhaust gas. The catalyst device 16 does not function sufficiently at a low temperature, but if the temperature becomes too high, it may not function normally and may be damaged. Therefore, an exhaust temperature sensor 51 for measuring the exhaust temperature is installed in the vicinity of the catalyst device 16.

As described above, in the engine 10, the flow path from the first intake pipe 32 to the first exhaust pipe 38 through the front cylinder 13 and the second exhaust pipe 48 from the second intake pipe 42 through the rear cylinder 14 It is formed independently of the flow path toward. The first and second exhaust pipes 38 and 48 meet at the collecting pipe 17 upstream of the catalyst device 16, but the collecting pipe 17 is behind the vehicle from the center C of the crankshaft in the crankcase 12 and the second exhaust. It is located in the range A in front of the vehicle from the upstream end 49 of the pipe 48. Therefore, more bends are formed in the second exhaust pipe 48 extending from the rear cylinder 14 to the catalyst device 16 than in the first exhaust pipe 38 extending from the front cylinder 13 to the catalyst device 16.

More specifically, as shown in FIG. 5, the first exhaust pipe 38 extends diagonally downward from the front surface of the front cylinder 13 toward the rear, and then gently bends toward the rear of the vehicle at the bent portion 56. It is bent at an angle. The second exhaust pipe 48 extends downward from the rear surface of the rear cylinder 14, and then bends at the bent portion 57 at a steep bending angle toward the front of the vehicle, and further bends toward the inside of the vehicle (left side) at the bent portion 58. It bends at a steep bending angle. Since the second exhaust pipe 48 follows a more complicated path than the first exhaust pipe 38, the second exhaust pipe 48 has more steep bends than the first exhaust pipe 38 and is formed to have a longer pipe length. ..

Further, as shown in FIG. 4, the engine 10 is provided with an ECU (Electrical Control Unit) 50 as a control unit for controlling the opening / closing operation of the first and second throttle valves 34 and 44. When the accelerator grip 52 is closed, the motors 35 and 45 of the first and second throttle bodies 33 and 43 are driven by the ECU 50 so that the first and second throttle valves 34 and 44 are closed. Immediately after the operation, the first throttle valve 34 is closed leaving a larger gap than the second throttle valve 44 so that the negative pressure in the front cylinder 13 does not become too large.

As described above, since the first exhaust pipe 38 has few sudden bends and a short pipe length, the exhaust efficiency of the front cylinder 13 is high due to the pulsation generated in the intake / exhaust process when the throttle opening is closed and the vehicle decelerates. Therefore, when the accelerator grip 52 is closed, the negative pressure in the front cylinder 13 tends to be larger than the negative pressure in the rear cylinder 14, but the first throttle valve 34 is closed leaving a gap. , Excessive negative pressure is not generated in the front cylinder 13. Therefore, as compared with the configuration in which the first and second throttle valves 34 and 44 are fully closed instantly, it is possible to sufficiently obtain the braking effect of the engine brake while suppressing the oil consumption due to the backflow of the engine oil.

A processor and a memory are mounted on the ECU 50, and the processor reads and executes a program stored in the memory to perform a throttle valve control process described later. As the processor, for example, a CPU (Central Processing Unit) or the like is used. The memory is composed of one or a plurality of storage media such as ROM (Read Only Memory) and RAM (Random Access Memory) depending on the intended use. In addition to the program, various parameters used for control processing are stored in the memory. Further, an accelerator position sensor 53 that detects the operation of the accelerator grip 52 is connected to the ECU 50.

The gap of the first throttle valve 34 immediately after the closing operation of the accelerator grip 52 was experimentally, empirically or theoretically obtained from past data and the like within a range in which excessive negative pressure was not generated in the front cylinder 13. The value is used. For example, the gap of the first throttle valve 34 may be set based on the pipe length of the first exhaust pipe 38.

With reference to FIGS. 6 and 7, the relationship between the opening degree of the throttle valve, the consumption amount of engine oil, and the vehicle speed when the accelerator grip is fully closed will be described. FIG. 6 is a diagram showing the relationship between the opening degree of the throttle valve and the vehicle speed of this embodiment. FIG. 7 is a diagram showing the relationship between the opening degree of the throttle valve and the vehicle speed of the comparative example. In FIGS. 6 and 7, the solid line W1 indicates the opening degree of the first throttle valve, the broken line W2 indicates the opening degree of the second throttle valve, and the solid line W3 indicates the vehicle speed. Further, here, reference numerals of FIG. 4 will be appropriately used for description.

In this embodiment of FIG. 6, the first throttle valve 34 is gradually closed as shown by the solid line W1, and the second throttle valve 44 is instantaneously closed as shown by the broken line W2. All of the closing operation time t ₁ of the accelerator grip 52, the second throttle valve 44 is fully closed is from the running time opening instant, the first throttle valve 34 from traveling time opening toward the completely closed faster ( The valve is closed at the first speed). At this time, the negative pressure of the front cylinder 13 is monitored from the detected value of the intake pressure sensor 39, and the first throttle valve 34 is closed at a speed that does not cause the negative pressure to become excessive. Time t ₂ in the first throttle valve 34 immediately after the operation is closed to a lower opening, leaving a gap. Closing speed of the first throttle valve 34 is decelerated after a time t _2, the first throttle valve 34 is closed at a low speed (second speed) until the fully closed.

As described above, when the accelerator grip 52 is fully closed, the negative pressure in the front cylinder 13 is larger than the negative pressure in the rear cylinder 14, but the first throttle valve 34 is closed leaving a gap. Therefore, the generation of excessive negative pressure in the front cylinder 13 is suppressed. The engine oil is not sucked into the combustion chamber side from the joint gap of the piston ring 64 due to the excessive negative pressure, and the consumption of the engine oil in the front cylinder 13 is suppressed. Further, even if the second throttle valve 44 is fully closed, an excessive negative pressure is not generated in the rear cylinder 14, and the consumption of engine oil in the rear cylinder 14 is suppressed.

As shown in the solid line W3, the engine brake acts on the front cylinder 13 and the rear cylinder 14 by the valve closing operation of the first and second throttle valves 34 and 44, and the vehicle speed is lowered. At this time, the first throttle valve 34 to be slightly delayed closing the second throttle valve 44, the vehicle speed after a time t ₂ is started to decrease significantly. From the fully closing operation time t ₁ of the accelerator grip 52 to the time t ₂ is very short, because the gap at time t ₁ after the first throttle valve 34 is also very small, a large braking effect of the vehicle's engine brake There is no effect.

On the other hand, in the comparative example of FIG. 7, as shown by the solid line W1 and the broken line W2, the first throttle valve 34 and the second throttle valve 44 are instantaneously closed. All of the closing operation time t ₁ of the accelerator grip 52, first, second throttle valve 34, 44 is fully closed instantaneously from the running time of opening. As shown by the solid line W3, the engine brake acts immediately on the front cylinder 13 and the rear cylinder 14, and the vehicle speed decreases. However, since the first throttle valve 34 is instantly fully closed, an excessive load is generated in the front cylinder 13. Therefore, the engine oil is sucked into the combustion chamber side and the consumption of the engine oil increases.

The control process of the throttle valve when the accelerator grip is fully closed will be described with reference to FIG. FIG. 8 is a flowchart of valve control of this embodiment. In addition, here, a reference | symbol of FIG. 4 is used as appropriate for description.

As shown in FIG. 8, when the accelerator grip 52 is operated (step S01), the accelerator opening degree is output from the accelerator position sensor 53 to the ECU 50. Based on the accelerator opening degree from the accelerator position sensor 53, the ECU 50 determines whether or not the accelerator grip 52 is fully closed (step S02). When it is determined that the accelerator grip 52 is not a fully closed operation (No in step S02), normal control is performed in which the first and second throttle valves 34 and 44 are opened and closed following the operation of the accelerator grip 52. To. During normal control, steps S01 and S02 are repeated until a fully closed operation is detected.

On the other hand, when it is determined that the accelerator grip 52 is fully closed (Yes in step S02), the motors 35 and 45 are simultaneously driven by the ECU 50, and the first and second throttle valves 34 and 44 are fully closed. Control is started in parallel (step S03). In the fully closed control of the first throttle valve 34, the negative pressure of the front cylinder 13 is monitored from the detected value of the intake pressure of the first intake pipe 32 by the intake pressure sensor 39 (step S04). Then, the ECU 50 closes the first throttle valve 34 at high speed, and determines whether or not the negative pressure of the front cylinder 13 exceeds a predetermined threshold value (step S05).

When the negative pressure of the front cylinder 13 does not exceed a predetermined threshold value (No in step S05), the processes of steps S04 and S05 are executed by the ECU 50 until the negative pressure of the front cylinder 13 exceeds the predetermined threshold value. When the negative pressure of the front cylinder 13 exceeds a predetermined threshold value (Yes in step S05), the ECU 50 closes the first throttle valve 34 at a low speed (step S06). When the first throttle valve 34 is fully closed, the ECU 50 stops the closing of the first throttle valve 34.

In the fully closed control of the second throttle valve 44, the ECU 50 instantly fully closes the second throttle valve 44 (step S07), and the closing of the second throttle valve 44 is stopped. In this way, the first and second throttle valves 34 and 44 are controlled independently, the first throttle valve 34 is closed without following the operation of the accelerator grip 52, and the second throttle valve 44 is closed. The valve is closed following the operation of the accelerator grip 52. Since the first throttle valve 34 is not fully closed instantly following the operation of the accelerator grip 52, the consumption of engine oil in the front cylinder 13 due to excessive negative pressure is suppressed, and the vehicle is decelerated by the braking force of the engine brake. Will be done.

When the first and second throttle valves 34 and 44 are stopped in the fully closed state, the ECU 50 determines whether or not the accelerator grip 52 is fully closed (step S08). When it is determined that the accelerator grip 52 is fully closed (Yes in step S08), the first and second throttle valves 34 and 44 are maintained in the fully closed state, assuming that the fully closed operation is continuing. If it is determined that the accelerator grip 52 is not fully closed (No in step S08), the ECU 50 switches the valve control of the first and second throttle valves 34 and 44 from the fully closed control to the normal control (step S09). ).

As described above, according to the present embodiment, when the first and second throttle valves 34 and 44 are closed during deceleration or the like, the first throttle valve 34 upstream of the front cylinder 13 is located upstream of the rear cylinder 14. The valve is closed leaving a gap larger than that of the second throttle valve 44. Therefore, the front cylinder 13 prevents the engine oil from being sucked into the combustion chamber due to excessive negative pressure, and the rear cylinder 14 can sufficiently obtain the braking force of the engine brake due to the negative pressure. Therefore, it is possible to achieve both the suppression of engine oil consumption and the braking effect of the engine brake.

In this embodiment, the negative pressure in the front cylinder 13 is monitored, and when the negative pressure in the front cylinder 13 exceeds the threshold value, the speed of the first throttle valve 34 is switched from high speed to low speed. However, it is not limited to this configuration. When the opening degree of the first throttle valve 34 reaches the target opening degree, the speed of the first throttle valve 34 may be switched from high speed to low speed. Hereinafter, the throttle valve control process of another embodiment will be described with reference to FIG. FIG. 9 is a flowchart of valve control of another embodiment. In addition, here, a reference | symbol of FIG. 4 is used as appropriate for description.

The processing of steps S11 and S12 is the same as that of steps S01 and S02 of this embodiment. When it is determined that the accelerator grip 52 is fully closed (Yes in step S12), the ECU 50 sets the target opening degree and the valve closing speed of the first throttle valve 34 (step S13). The target opening degree and the valve closing speed are set in two stages with respect to the first throttle valve 34 so that an excessive negative pressure is not generated in the front cylinder 13. A low opening that leaves a gap is set as the target opening in the first stage, and a high speed is set as the valve closing speed in the first stage. Fully closed is set as the target opening in the second stage, and low speed is set as the valve closing speed in the second stage.

Next, the motors 35 and 45 are simultaneously driven by the ECU 50, and the first and second throttle valves 34 and 44 are fully closed and controlled in parallel. In the fully closed control of the first throttle valve 34, it is determined whether or not the first throttle valve 34 is closed at high speed by the ECU 50 (step S14) and the first throttle valve 34 is closed to a low opening. (Step S15). When the first throttle valve 34 is not closed to a low opening (No in step S15), the processing of steps S14 and S15 is performed by the ECU 50 until the opening of the first throttle valve 34 becomes a low opening. Will be done.

When the first throttle valve 34 is closed to a low opening degree (Yes in step S15), the ECU 50 closes the first throttle valve 34 at a low speed (step S16), and the first throttle valve 34 is fully closed. Whether or not it is closed is determined (step S17). When the first throttle valve 34 is not fully closed (No in step S17), the processes of steps S16 and S17 are executed until the first throttle valve 34 is fully closed by the ECU 50. When the first throttle valve 34 is fully closed (Yes in step S17), the ECU 50 stops closing the first throttle valve 34.

In the fully closed control of the second throttle valve 44, the ECU 50 instantly fully closes the second throttle valve 44 (step S18), and the closing of the second throttle valve 44 is stopped. In this way, the first and second throttle valves 34 and 44 are controlled independently, the first throttle valve 34 is closed without following the operation of the accelerator grip 52, and the second throttle valve 44 is closed. The valve is closed following the operation of the accelerator grip 52. Since the first throttle valve 34 is not fully closed instantly following the operation of the accelerator grip 52, the consumption of engine oil in the front cylinder 13 due to excessive negative pressure is suppressed, and the vehicle is decelerated by the braking force of the engine brake. Will be done. The following steps 19 and S20 are the same as steps S08 and S09 of this embodiment. Even with such a process, it is possible to achieve both the suppression of engine oil consumption and the braking effect of the engine brake.

Further, although an example in which the throttle valve control of this embodiment is applied to a two-cylinder V-type engine has been described, the present invention is not limited to this configuration. The control of the throttle valve of this embodiment may be applied to an engine having three or more cylinders, and may be applied not only to a V-type engine but also to an in-line engine and a horizontally opposed engine. For example, in an engine having three or more cylinders, the throttle valve upstream of the cylinder having the largest negative pressure is closed leaving a larger gap than the other throttle valves.

Further, in this embodiment, the second throttle valve is fully closed, but the second throttle valve does not have to be fully closed. The second throttle valve may be closed leaving a gap smaller than the gap of the first throttle valve.

Further, in the present embodiment, the first throttle valve is closed with a gap left, but the configuration is not limited to this. The first throttle valve may be closed once and then opened so as to leave a gap.

Further, in the present embodiment, the first throttle valve is configured to be fully closed after closing to a low opening degree leaving a gap, but the configuration is not limited to this. The low opening state may be maintained after the first throttle valve closes to a low opening leaving a gap.

Further, in this embodiment, the negative pressure in the front cylinder is formed larger than the negative pressure in the rear cylinder, but the present invention is not limited to this configuration. The negative pressure in the rear cylinder may be formed larger than the negative pressure in the front cylinder. In this case, the second exhaust pipe may be formed shorter than the first exhaust pipe.

Further, in this embodiment, the front side cylinder and the rear side cylinder separated in the front-rear direction of the vehicle are illustrated as a plurality of cylinders, but the present invention is not limited to this configuration. The plurality of cylinders may be formed side by side in the left-right direction of the vehicle without being divided into front and rear.

Further, the engine of this embodiment has a configuration having a front cylinder and a rear cylinder, but is not limited to this configuration. The engine may have a plurality of cylinders, and the negative pressure in some of the cylinders may be formed to be larger than the negative pressure in the other cylinders. For example, the negative pressure in two of the three or more cylinders may be formed larger than the negative pressure in the other cylinder. In this case, the throttle valves upstream of the two cylinders having a large negative pressure in the cylinders are closed leaving a larger gap than the throttle valves upstream of the other cylinders. When the engine has cylinders with different negative pressures in three or more cylinders, the throttle valves upstream of the plurality of cylinders are closed in descending order of the negative pressures in the cylinders, leaving a large gap. May be good.

Further, although the configuration in which the throttle valve control of this embodiment is applied to the motorcycle has been described, the present invention is not limited to this configuration. The control of the throttle valve in this embodiment is performed by other vehicles on which the throttle valve is installed, for example, a motorcycle, a buggy type tricycle, and special equipment such as a personal watercraft, a lawn mower, and an outboard motor. It is also possible to apply to.

Further, the program of the throttle valve control process of the present embodiment may be stored in the storage medium. The storage medium is not particularly limited, but may be a non-transient storage medium such as an optical disk, a magneto-optical disk, or a flash memory.

As described above, the engine (10) of the present embodiment has an engine body (11) having a plurality of cylinders (front cylinder 13, rear cylinder 14) and a plurality of throttle valves (11) located on the intake side of the plurality of cylinders. An engine (10) including a first throttle valve 34, a second throttle valve 44) and a control unit (ECU 50) for controlling the opening / closing operation of a plurality of throttle valves, and one of a plurality of cylinders. The negative pressure in the cylinder (front cylinder 13) is larger than the negative pressure in the other cylinders (rear cylinder 14), and the control unit is located upstream of some cylinders when the plurality of throttle valves are closed. Some throttle valves (first throttle valve 34) are closed leaving a larger gap than other throttle valves (second throttle valve 44) upstream of the other cylinder. According to this configuration, when the throttle valve is closed such as during deceleration, some throttle valves upstream of some cylinders having a large internal negative pressure are larger than other throttle valves upstream of other cylinders. Close the valve leaving a gap. Therefore, in some cylinders, suction of engine oil into the combustion chamber due to excessive negative pressure is prevented, and in other cylinders, sufficient braking force of the engine brake due to negative pressure can be obtained. Therefore, it is possible to achieve both the suppression of engine oil consumption and the braking effect of the engine brake.

In the engine of the present embodiment, the control unit closes the plurality of throttle valves upstream of the plurality of cylinders in descending order of the negative pressure in the plurality of cylinders, leaving a large gap. According to this configuration, the opening degree of the throttle valve is adjusted according to the variation of the negative pressure in the plurality of cylinders, and it is possible to further improve both the suppression of engine oil consumption and the braking effect of the engine brake.

In the engine of the present embodiment, a plurality of exhaust pipes (first exhaust pipe 38, second exhaust pipe 48) connected to the exhaust side of the plurality of cylinders are provided, and some cylinders among the plurality of exhaust pipes are provided. A part of the exhaust pipe (first exhaust pipe 38) connected to the exhaust side is formed shorter than the other exhaust pipe (second exhaust pipe 48) connected to the exhaust side of the other cylinder. When closing multiple throttle valves, the control unit closes some throttle valves upstream of some exhaust pipes, leaving a larger gap than other throttle valves upstream of other exhaust pipes. .. According to this configuration, the negative pressure of some cylinders connected to the short exhaust pipe tends to be larger than the negative pressure in other cylinders. By closing some throttle valves upstream of some cylinders leaving a larger gap than other throttle valves upstream of other cylinders, it is possible to suppress the generation of excessive load on some cylinders. Can be done.

In the engine of this embodiment, the plurality of cylinders are a front cylinder (13) and a rear cylinder (14) separated in the front-rear direction of the vehicle, and some exhaust pipes are connected to the exhaust side of the front cylinder. The exhaust pipe (38), the other exhaust pipe is the second exhaust pipe (48) connected to the exhaust side of the rear cylinder, and some throttle valves are the first located on the intake side of the front cylinder. Throttle valve (34), and the other throttle valve is a second throttle valve (44) located on the intake side of the rear cylinder. According to this configuration, in an engine in which a plurality of cylinders are arranged in the front and rear, it is possible to achieve both suppression of engine oil consumption and braking effect of engine braking.

In the engine of this embodiment, a catalyst device (16) is connected to the downstream side of a plurality of exhaust pipes, and the engine body has a crankcase (12) accommodating a crankshaft, and the first exhaust pipe and The second exhaust pipe joins at the collecting pipe upstream of the catalyst device, and the collecting pipe is located behind the vehicle from the center of the crankshaft and in front of the vehicle from the upstream end of the second exhaust pipe. According to this configuration, more bends are formed in the second exhaust pipe extending from the rear cylinder to the catalyst device than in the first exhaust pipe extending from the front cylinder to the catalyst device. Therefore, the exhaust efficiency of the front cylinder connected to the first exhaust pipe is higher than that of the rear cylinder connected to the second exhaust pipe, and the negative pressure in the front cylinder is larger than the negative pressure in the rear cylinder. Easy to become. Since the first throttle valve is closed with a sufficient gap left, it is possible to suppress the generation of excessive negative pressure on the front cylinder.

In the engine of the present embodiment, the control unit closes the first throttle valve at the first speed leaving a gap, and then closes the valve at the second speed, which is slower than the first speed, until it is fully closed. , The second throttle valve is instantly closed until it is fully closed. According to this configuration, it is possible to increase the braking force of the engine brakes of the front cylinder and the rear cylinder while suppressing the suction of engine oil into the combustion chamber due to excessive negative pressure in the front cylinder.

The vehicle of this embodiment is equipped with the above engine. According to this configuration, the opening / closing operation of the throttle valve is controlled according to the magnitude of the negative pressure in the plurality of cylinders, and it is possible to suppress the consumption of engine oil in the vehicle and to achieve both the braking effect of the engine brake.

Although this embodiment has been described, as another embodiment, the above embodiment and the modified examples may be combined in whole or in part.

Further, the technique of the present invention is not limited to the above-described embodiment, and may be variously modified, replaced, or modified without departing from the spirit of the technical idea. Furthermore, if the technical idea can be realized in another way by the advancement of the technology or another technology derived from it, it may be carried out by using that method. Therefore, the claims cover all embodiments that may be included within the scope of the technical idea.

10: Engine 11: Engine body 12: Crankcase 13: Front cylinder 14: Rear cylinder 16: Catalyst device 17: Collective pipe 34: First throttle valve 38: First exhaust pipe 44: Second throttle valve 48 : Second exhaust pipe 49: Upstream end 50 of the second exhaust pipe: ECU (control unit)

Claims (7)

An engine including an engine body having a plurality of cylinders, a plurality of throttle valves located on the intake side of the plurality of cylinders, and a control unit for controlling the opening / closing operation of the plurality of throttle valves.
The negative pressure in some of the plurality of cylinders is larger than the negative pressure in other cylinders.
When the plurality of throttle valves are closed, the control unit closes some throttle valves upstream of the part of the cylinders, leaving a larger gap than other throttle valves upstream of the other cylinders. An engine characterized by doing. The engine according to claim 1, wherein the control unit closes the plurality of throttle valves upstream of the plurality of cylinders in descending order of negative pressure in the plurality of cylinders, leaving a large gap. .. A plurality of exhaust pipes connected to the exhaust side of the plurality of cylinders are provided.
Of the plurality of exhaust pipes, a part of the exhaust pipes connected to the exhaust side of the part of the cylinders is formed shorter than the other exhaust pipes connected to the exhaust side of the other cylinders.
When the plurality of throttle valves are closed, the control unit closes the part of the throttle valve upstream of the part of the exhaust pipe with a gap larger than that of the other throttle valve upstream of the other exhaust pipe. The engine according to claim 1 or 2, wherein the valve is closed while being left. The plurality of cylinders are a front cylinder and a rear cylinder separated in the front-rear direction of the vehicle.
The part of the exhaust pipe is a first exhaust pipe connected to the exhaust side of the front cylinder.
The other exhaust pipe is a second exhaust pipe connected to the exhaust side of the rear cylinder.
Some of the throttle valves are first throttle valves located on the intake side of the front cylinder.
The engine according to claim 3, wherein the other throttle valve is a second throttle valve located on the intake side of the rear cylinder. A catalyst device is connected to the downstream side of the plurality of exhaust pipes.
The engine body has a crankcase that houses the crankshaft.
The first exhaust pipe and the second exhaust pipe meet at an collecting pipe upstream of the catalyst device, and the collecting pipe is behind the vehicle from the center of the crankshaft and at the upstream end of the second exhaust pipe. The engine according to claim 4, wherein the engine is located in front of the vehicle. The control unit closes the first throttle valve at the first speed leaving a gap, and then closes the valve at a second speed lower than the first speed until it is fully closed. The engine according to claim 4 or 5, wherein the throttle valve of the above is instantly closed until it is fully closed. A vehicle equipped with the engine according to any one of claims 1 to 6.

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