Vehicle

Abstract

To suppress accumulation of condensate water in an exhaust flow passage.SOLUTION: A vehicle comprises: an engine; an intake flow passage through which air to be supplied to the engine flows; an exhaust flow passage through which gas discharged from the engine flows; a throttle valve installed in the intake flow passage; a ventilation section which is installed at least either in the intake flow passage or in the exhaust flow passage and generates an air flow; and a control device. When a condition to stop the engine in operation is met, a processor of the control device executes special stop control to stop the engine so as to become a valve overlapping state which indicates that both the intake and exhaust valves are under an open state when the engine stops. Additionally, the processor performs a process to put the throttle valve into the open state after the engine stops.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vehicle. [Background technology]

[0002] For example, Patent Document 1 discloses a hybrid vehicle that determines that condensed water may be present in the engine combustion chamber when the coolant temperature is below a threshold and executes scavenging control. In such a hybrid vehicle, scavenging control controls the variable valve mechanism so that the intake valve opening timing and exhaust valve closing timing are at top dead center, thereby discharging condensed water from the combustion chamber into the exhaust pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-80654 Summary of the Invention [Problem to be solved by the invention]

[0004] When an engine is stopped while it is running, moisture contained in the gas emitted from the engine may condense and remain in the exhaust flow path. This condensed water may adhere to, for example, an exhaust sensor installed in the exhaust flow path. When the engine is restarted and the exhaust sensor is heated to activate it, if the condensed water adheres to the exhaust sensor, the exhaust sensor may be damaged by the thermal shock caused by evaporation.

[0005] Therefore, an object of the present invention is to provide a vehicle that can prevent condensed water from accumulating in the exhaust flow path. [Means for solving the problem]

[0006] In order to solve the above problem, a vehicle according to one embodiment of the present invention comprises: The engine and an intake flow path through which air supplied to the engine flows; an exhaust flow path through which gas exhausted from the engine flows; a throttle valve provided in the intake passage; a ventilation section provided in at least one of the intake flow path and the exhaust flow path, which generates a gas flow; a control device; Equipped with The engine is an intake valve capable of opening and closing an intake port connected to the intake passage; an exhaust valve capable of opening and closing an exhaust port connected to the exhaust flow path; and The control device one or more processors; one or more memories coupled to said processor; and The processor: When a condition for stopping the engine in operation is met, performing specific stop control to stop the engine so that a valve overlap state is reached, which indicates that both the intake valve and the exhaust valve are open, when the engine is stopped; After the engine is stopped, the throttle valve is opened. Execute the process including. [Effects of the Invention]

[0007] According to the present invention, it is possible to prevent condensed water from remaining in the exhaust flow passage. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a vehicle according to the first embodiment. [Figure 2] FIG. 2 is a flowchart showing an example of the flow of operations of the vehicle control unit in the first embodiment. [Figure 3]FIG. 3 is a flowchart illustrating the flow of the specific stop control. [Figure 4] FIG. 4 is a diagram for explaining the valve overlap state, the specific crank angle range, and throttle valve opening control. [Figure 5] FIG. 5 is a schematic diagram showing the configuration of a vehicle according to the second embodiment. [Figure 6] FIG. 6 is a cross-sectional view illustrating the configuration of the running wind acquisition unit. [Figure 7] FIG. 7 is a flowchart showing an example of the flow of operations of the vehicle control unit in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for facilitating understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0010] (First embodiment) 1 is a schematic diagram showing the configuration of a vehicle 1 according to the first embodiment. The vehicle 1 may be an engine vehicle equipped with an engine 10 as a drive source, or may be a hybrid vehicle equipped with an engine 10 and a motor generator (not shown) as drive sources. In the first embodiment, the vehicle 1 may also be referred to as the host vehicle.

[0011] The engine 10 has pistons 20, cylinders 22, intake ports 24, exhaust ports 26, intake valves 28, exhaust valves 30, and injectors 32. The engine 10 in Fig. 1 is a so-called four-cylinder engine, which has four pairs of pistons 20 and cylinders 22. However, the engine 10 is not limited to a four-cylinder engine, and may have any number of cylinders.

[0012] The piston 20 is slidably housed inside the cylinder 22. An intake port 24 and an exhaust port 26 communicate with the interior of the cylinder 22. An intake valve 28 is configured to be able to open and close the intake port 24. An exhaust valve 30 is configured to be able to open and close the exhaust port 26.

[0013] When the intake valve 28 is open, air is sent into the cylinder 22 through the intake port 24. The injector 32 injects fuel into the cylinder 22. Inside the cylinder 22, an air-fuel mixture is ignited by a spark plug (not shown) and burns, causing the piston 20 to slide inside the cylinder 22. The piston 20 is connected to a crankshaft 36 via a connecting rod 34. As the piston 20 slides, the crankshaft 36 rotates. The driving force of the engine 10 due to the rotation of the crankshaft 36 is transmitted to the wheels.

[0014] When the exhaust valve 30 is opened, gas inside the cylinder 22 is discharged to the outside of the cylinder 22 through the exhaust port 26 .

[0015] In addition to the engine 10, the vehicle 1 is equipped with an intake passage 40, an exhaust passage 42, an air cleaner 44, a ventilation section 46, a throttle valve 48, a catalyst 50, a muffler 52, an exhaust port 54, a crank angle sensor 60, a cam angle sensor 62, a speed sensor 64, and a control device 70.

[0016] The intake flow path 40 is connected to the intake ports 24. The intake flow path 40 includes an intake manifold 80, which is a multi-branched pipe that forms multiple outlets for one inlet. The inlet of the intake manifold 80 is connected to the outlet of the throttle valve 48. The outlets of the intake manifold 80 are connected to each of the intake ports 24 in the engine 10. The intake manifold 80 branches the intake flow path 40, which connects from the throttle valve 48 to the intake ports 24, into branches for each of the intake ports 24.

[0017] Air that is sent into the cylinder 22 through the intake port 24, in other words, air that is supplied to the engine 10, flows through the intake flow path 40. Hereinafter, for ease of explanation, the side along the intake flow path 40 that is relatively far from the engine 10 may be referred to as the upstream side of the intake flow path 40, and the side along the intake flow path 40 that is relatively closer to the engine 10 may be referred to as the downstream side of the intake flow path 40.

[0018] The exhaust flow path 42 is connected to the exhaust ports 26. The exhaust flow path 42 includes an exhaust manifold 82, which is a collecting pipe that forms one outlet for multiple inlets. The inlets of the exhaust manifold 82 are connected to each of the exhaust ports 26 in the engine 10. The outlets of the exhaust manifold 82 are connected to the inlet of the catalyst 50. The exhaust manifold 82 collects the exhausts from each of the exhaust ports 26 into one exhaust flow path 42.

[0019] Gas discharged to the outside of the cylinder 22 through the exhaust port 26, in other words, gas discharged from the engine 10, flows through the exhaust flow path 42. Hereinafter, for ease of explanation, the side along the exhaust flow path 42 that is relatively closer to the engine 10 may be referred to as the upstream side of the exhaust flow path 42, and the side along the exhaust flow path 42 that is relatively farther from the engine 10 may be referred to as the downstream side of the exhaust flow path 42.

[0020] An air cleaner 44, a ventilation unit 46, and a throttle valve 48 are provided in intake flow path 40 in this order along the direction of air flow, i.e., from upstream to downstream. Air cleaner 44 includes an intake port 44A that takes in air from outside vehicle 1 into intake flow path 40. Air cleaner 44 removes foreign matter from the air taken into intake flow path 40.

[0021] The ventilation section 46 is configured to generate a flow of gas in the intake flow path 40. The ventilation section 46 includes, for example, a pump 46A that can send air into the engine 10 through the intake flow path 40. The ventilation section 46 including the pump 46A is not limited to being provided between the air cleaner 44 and the throttle valve 48, and may be provided at any position in the intake flow path 40. The pump 46A may be an electric pump, or may be operated by a hydraulic or mechanical mechanism.

[0022] The throttle valve 48 is configured to be able to change its opening, and is able to adjust the flow rate of air flowing through the intake passage 40 to a flow rate corresponding to its opening. For example, the throttle valve 48 adjusts the amount of air sent into the cylinder 22 in response to the driver's acceleration / deceleration operation. Furthermore, the opening of the throttle valve 48 may be controlled by a control device 70 (described later) separately from the driver's acceleration / deceleration operation.

[0023] In the exhaust flow path 42, a catalyst 50, a muffler 52, and an exhaust port 54 are provided in this order along the direction of gas flow, i.e., from upstream to downstream. The catalyst 50 is, for example, a three-way catalyst, and purifies the gas discharged from the cylinder 22. The muffler 52 is configured such that the cross-sectional area of ​​the inside of the exhaust flow path 42 is larger than that of the portion other than the muffler 52. The muffler 52 reduces exhaust noise. The gas that has flowed through the exhaust flow path 42 is discharged to the space outside the vehicle 1 through the exhaust port 54.

[0024] Hereinafter, the flow path through which gas flows from the intake port 44A of the intake flow path 40 to the exhaust port 54 of the exhaust flow path 42 may be referred to as a gas flow path 56.

[0025] The crank angle sensor 60 detects the crank angle indicating the rotation angle of the crankshaft 36. The cam angle sensor 62 detects the cam angle indicating the rotation angle of the camshaft. The speed sensor 64 detects the speed of the vehicle, in other words, the vehicle speed. Although not shown, an exhaust sensor is provided in the exhaust flow path 42. The exhaust sensor detects the state of the exhaust from the engine 10. The exhaust sensor includes at least one of an O2 (oxygen) sensor, an A / F (air-fuel ratio) sensor, and an exhaust temperature sensor. The O2 sensor and the A / F sensor detect the oxygen concentration in the gas flowing through the exhaust flow path 42. The exhaust temperature sensor detects the temperature of the gas flowing through the exhaust flow path 42.

[0026] The control device 70 includes one or more processors 90 and one or more memories 92 connected to the processors 90. The memories 92 include a ROM in which programs and the like are stored and a RAM as a work area. The processor 90 executes the programs to function as a vehicle control unit 94 that controls the entire vehicle 1.

[0027] The vehicle control unit 94 controls, for example, starting, driving, and stopping of the engine 10. The vehicle control unit 94 also monitors the signals from the crank angle sensor 60 and the cam angle sensor 62 at predetermined time intervals, and calculates the crank angular velocity, which indicates the angular velocity of the crankshaft 36, from the amount of change in the crank angle and the amount of change in the cam angle and the time required for the change. The vehicle control unit 94 is not limited to controlling the engine 10, and may control any part of the vehicle 1.

[0028] When the engine 10 is stopped while it is running, moisture contained in the gas emitted from the engine 10 may condense and accumulate in the exhaust flow path 42. This condensed water may adhere to, for example, an exhaust sensor provided in the exhaust flow path 42. When the engine 10 is restarted and the exhaust sensor is heated to activate it, if the condensed water adheres to the exhaust sensor, the exhaust sensor may be damaged by the thermal shock caused by evaporation.

[0029] Therefore, the vehicle control unit 94 of the vehicle 1 of the first embodiment performs the following series of processes shown in FIG. 2 to discharge the gas in the exhaust flow path 42 to the outside.

[0030] 2 is a flowchart showing an example of the flow of operations of the vehicle control unit 94 in the first embodiment. The vehicle control unit 94 repeatedly performs the series of processes shown in FIG. 2 every time a predetermined interrupt timing arrives, which occurs every time a predetermined time elapses.

[0031] When a predetermined interrupt timing arrives, the vehicle control unit 94 determines whether or not the conditions for stopping the engine 10 in operation are met (S10).

[0032] For example, when the vehicle control unit 94 determines that a transition from engine drive to motor drive is occurring in a hybrid vehicle, the vehicle control unit 94 may determine that a condition for stopping the engine 10 is met. Also, when the vehicle control unit 94 determines that the engine 10 is operating and is inertial running in a hybrid vehicle or an internal combustion vehicle, the vehicle control unit 94 may determine that a condition for stopping the engine 10 is met. Note that the specific conditions for determining whether or not a condition for stopping the engine 10 is met are not limited to the exemplified conditions, and may be set to any condition for which stopping the engine 10 is desired.

[0033] When it is determined that the condition for stopping the engine 10 in operation is not met (NO in S10), the vehicle control unit 94 ends the series of processes in FIG.

[0034] When it is determined that the condition for stopping the operating engine 10 is met (YES in S10), the vehicle control unit 94 performs specific stop control (S11). The specific stop control is a control for stopping the engine 10 so that, when the engine 10 is stopped, a valve overlap state is reached in some of the cylinders 22, indicating that both the intake valves 28 and the exhaust valves 30 are open. The specific stop control will be described in detail later.

[0035] When the specific stop control is performed and the engine 10 is stopped, the intake port 24 of some of the cylinders 22 in the stopped engine 10 communicates with the exhaust port 26 through the inside of the cylinder 22.

[0036] After the specific stop control is performed and the engine 10 is completely stopped, the vehicle control unit 94 opens the throttle valve 48 (S12). For example, the throttle valve 48 is set to a fully open state, but it is not limited to a fully open state and may be set to any opening that allows air to flow.

[0037] When the engine 10 is stopped in a valve overlap state and the throttle valve 48 is opened, the gas flow path 56 between the intake port 44A of the intake flow path 40 and the exhaust port 54 of the exhaust flow path 42 becomes connected through the engine 10.

[0038] Next, the vehicle control unit 94 operates the pump 46A provided in the intake flow path 40 (S13), and ends the series of processes. When the pump 46A operates, a flow from the upstream side to the downstream side is generated in the gas inside the intake flow path 40. Because the intake flow path 40 is in communication with the exhaust flow path 42 through the inside of the cylinder 22, the flow generated by the pump 46A is transmitted to the exhaust flow path 42 through the inside of the cylinder 22.

[0039] Then, when the engine 10 is stopped, the pump 46A operates to discharge the gas in the gas flow path 56 to the outside of the vehicle 1. For example, the gas inside the exhaust flow path 42 is discharged to the outside.

[0040] In this way, in the vehicle 1 of the first embodiment, when the engine 10 is stopped, the gas inside the exhaust flow path 42 is discharged to the outside, thereby preventing gas from accumulating in the exhaust flow path 42. As a result, in the vehicle 1 of the first embodiment, moisture contained in the gas is also discharged to the outside, preventing condensed water from accumulating in the exhaust flow path 42. As a result, in the vehicle 1 of the first embodiment, condensed water can be prevented from adhering to the exhaust sensor provided in the exhaust flow path 42, and it becomes possible to prevent damage to the exhaust sensor when the engine 10 is restarted.

[0041] Fig. 3 is a flowchart illustrating the flow of the specific stop control. The vehicle control unit 94 repeats the specific stop control of Fig. 3 at predetermined time intervals until the piston 20 is completely stopped. The predetermined time is set to an arbitrary time that allows the process of Fig. 3 to be repeated multiple times until at least the moving piston 20 is completely stopped.

[0042] First, the vehicle control unit 94 acquires the current crank angle and cam angle from the crank angle sensor 60 and the cam angle sensor 62, respectively (S20).

[0043] Next, the vehicle control unit 94 derives the crank angular velocity at the acquired crank angle (S21).

[0044] Next, the vehicle control unit 94 derives an estimated crank angle that indicates an estimated value of the crank angle when the engine 10 is stopped, based on the current crank angle, cam angle, and current crank angular velocity (S22). For example, a map that associates the crank angle, cam angle, crank angular velocity, and estimated crank angle may be stored in advance in the memory 92, and the vehicle control unit 94 may derive the estimated crank angle from the map, the current crank angle, cam angle, and current crank angular velocity.

[0045] Next, the vehicle control unit 94 controls the opening degree of the throttle valve 48 based on the derived estimated crank angle (S23). More specifically, the vehicle control unit 94 controls the opening degree of the throttle valve 48 so that the estimated crank angle falls within a specific crank angle range that indicates the range of crank angles within which the intake valve 28 and the exhaust valve 30 are in a valve overlap state.

[0046] 4 is a diagram illustrating the valve overlap state, the specific crank angle range, and the opening control of the throttle valve 48. For ease of explanation, in FIG. 4, the four cylinders 22 of the engine 10 are referred to as a first cylinder, a second cylinder, a third cylinder, and a fourth cylinder. In FIG. 4, "TDC" means the crank angle at which the piston 20 is at top dead center, and "BDC" means the crank angle at which the piston 20 is at bottom dead center.

[0047] Each cylinder 22 of the engine 10 repeats the following strokes in this order: intake stroke, compression stroke, combustion stroke, and exhaust stroke. In the engine 10, the strokes of each cylinder 22 are shifted relative to one another so that the same stroke does not overlap in each cylinder 22.

[0048] For example, when the first cylinder is on the intake stroke, the second cylinder is on the combustion stroke, the third cylinder is on the exhaust stroke, and the fourth cylinder is on the compression stroke. When the first cylinder is on the compression stroke, the second cylinder is on the exhaust stroke, the third cylinder is on the intake stroke, and the fourth cylinder is on the combustion stroke. When the first cylinder is on the combustion stroke, the second cylinder is on the intake stroke, the third cylinder is on the compression stroke, and the fourth cylinder is on the exhaust stroke. When the first cylinder is on the exhaust stroke, the second cylinder is on the compression stroke, the third cylinder is on the combustion stroke, and the fourth cylinder is on the intake stroke.

[0049] Furthermore, the piston 20 moves from the bottom dead center toward the top dead center during the exhaust stroke, and moves from the top dead center toward the bottom dead center during the intake stroke.

[0050] In the diagram of each cylinder 22 in FIG. 4, a solid line A10 shows an example of the shift amount of the intake valve 28 relative to the crank angle, and a dashed line A12 shows an example of the shift amount of the exhaust valve 30 relative to the crank angle.

[0051] For example, the intake valve 28 is controlled to open before the top dead center, which corresponds to the start of the intake stroke, and close after the bottom dead center, which corresponds to the end of the intake stroke. The exhaust valve 30 is controlled to open before the bottom dead center, which corresponds to the start of the exhaust stroke, and close after the top dead center, which corresponds to the end of the exhaust stroke.

[0052] As a result, both the intake valve 28 and the exhaust valve 30 are open from the time the intake valve 28 begins to open until the exhaust valve 30 closes. In other words, the intake valve 28 and the exhaust valve 30 are in a valve overlap state from the time the intake valve 28 begins to open until the exhaust valve 30 closes.

[0053] In FIG. 4, the range of crank angles in which the intake valve 28 and the exhaust valve 30 are in a valve overlap state, that is, the specific crank angle range, is indicated by cross-hatching.

[0054] In engine 10, because the stroke of each cylinder 22 is shifted, the crank angle range in which the intake valve 28 and exhaust valve 30 are in a valve overlap state is also shifted for each cylinder 22, as shown in the diagram of each cylinder 22 in Figure 4.

[0055] For the first cylinder, a first start crank angle corresponding to the opening timing of the intake valve 28 in the first cylinder is set to any crank angle between 630 degrees and 720 degrees (0 degrees). Also, for the first cylinder, a first end crank angle corresponding to the closing timing of the exhaust valve 30 in the first cylinder is set to any crank angle between 0 degrees (720 degrees) and 90 degrees. In this way, for the first cylinder, the valve overlap state is established in a first range between the first start crank angle and the first end crank angle, which range includes the crank angle of 0 degrees (720 degrees).

[0056] For the second cylinder, a second start crank angle corresponding to the opening timing of the intake valve 28 in the second cylinder is set to any crank angle between 270 degrees and 360 degrees. Also, for the second cylinder, a second end crank angle corresponding to the closing timing of the exhaust valve 30 in the second cylinder is set to any crank angle between 360 degrees and 450 degrees. In this way, for the second cylinder, the valve overlap state is established in a second range between the second start crank angle and the second end crank angle, which includes the crank angle of 360 degrees.

[0057] For the third cylinder, a third start crank angle corresponding to the opening timing of the intake valve 28 for the third cylinder is set to any crank angle between 90 degrees and 180 degrees. Also, for the third cylinder, a third end crank angle corresponding to the closing timing of the exhaust valve 30 for the third cylinder is set to any crank angle between 180 degrees and 270 degrees. In this way, for the third cylinder, the valve overlap state is established in a third range between the third start crank angle and the third end crank angle, which includes the crank angle of 180 degrees.

[0058] For the fourth cylinder, a fourth start crank angle corresponding to the opening timing of the intake valve 28 of the fourth cylinder is set to any crank angle between 450 degrees and 540 degrees. Also, for the fourth cylinder, a fourth end crank angle corresponding to the closing timing of the exhaust valve 30 of the fourth cylinder is set to any crank angle between 540 degrees and 630 degrees. In this case, the fourth cylinder is in a valve overlap state in a fourth range between the fourth start crank angle and the fourth end crank angle, which includes the crank angle of 540 degrees.

[0059] That is, the specific crank angle range includes the above-mentioned first range, second range, third range, and fourth range.

[0060] In the engine 10, when the crank angle falls within any of the first, second, third, and fourth ranges described above, the valve overlap state is established in one of the four cylinders 22. When the engine 10 is stopped, if the valve overlap state is established in one of the four cylinders 22, the intake passage 40 and the exhaust passage 42 are connected through the cylinder 22 in the valve overlap state.

[0061] When the intake valve 28 and the exhaust valve 30 are in a valve overlap state, the piston 20 is located at or near top dead center. When the piston 20 is located near top dead center, the volume of the combustion chamber inside the cylinder 22 is smaller than when the piston 20 is located near bottom dead center, and therefore the pressure acting on the piston 20 is greater. When the valve overlap state occurs, the interior of the cylinder 22 communicates with the throttle valve 48 through the intake passage 40, and therefore it is possible to change the pressure acting on the piston 20 by changing the opening of the throttle valve 48.

[0062] For example, when the opening of the throttle valve 48 is increased, the gas inside the cylinder 22 is more likely to escape through the throttle valve 48, and the pressure on the piston 20 can be decreased. When the pressure on the piston 20 is reduced, the sliding of the piston 20 due to inertia until the piston 20 stops is less likely to be hindered. This makes it possible to lengthen the time until the piston 20 stops compared to before the pressure on the piston 20 was reduced, and to shift the crank angle when the piston 20 stops in a larger direction.

[0063] Conversely, when the opening of the throttle valve 48 is decreased, it becomes more difficult for the gas inside the cylinder 22 to escape through the throttle valve 48, and the pressure on the piston 20 can be increased. When the pressure on the piston 20 increases, the sliding of the piston 20 due to inertia until the piston 20 stops is more likely to be hindered. This makes it possible to shorten the time it takes for the piston 20 to stop compared to before the pressure on the piston 20 was increased, and to shift the crank angle when the piston 20 stops in a smaller direction.

[0064] Based on this, the vehicle control unit 94 controls the opening degree of the throttle valve 48 so that the estimated crank angle falls within the specific crank angle range.

[0065] More specifically, the vehicle control unit 94 determines the specific crank angle range that is closest to the derived estimated crank angle from among multiple specific crank angle ranges (i.e., the first range, second range, third range, and fourth range described above) as the target specific crank angle range.

[0066] 4, when the estimated crank angle deviates from a specific crank angle range of interest in a direction in which the crank angle is smaller, the vehicle control unit 94 controls the opening of the throttle valve 48 to be larger than the current opening. At this time, the amount by which the opening of the throttle valve 48 is increased may be determined according to the amount by which the estimated crank angle deviates from the specific crank angle range of interest.

[0067] On the other hand, if the estimated crank angle deviates from the target specific crank angle range in a direction in which the crank angle is larger, the vehicle control unit 94 controls the opening of the throttle valve 48 to be smaller than the current opening. At this time, the amount by which the opening of the throttle valve 48 is reduced may be determined according to the amount by which the estimated crank angle deviates from the target specific crank angle range.

[0068] Furthermore, if the estimated crank angle falls within the target specific crank angle range, the vehicle control unit 94 maintains the current opening degree of the throttle valve 48.

[0069] For example, assume that the target specific crank angle range is determined to be the second range including a crank angle of 360 degrees. In this example, if the estimated crank angle is a value in the range greater than or equal to 270 degrees and less than the second start crank angle, the vehicle control unit 94 increases the opening of the throttle valve 48 from the current opening. Also, in this example, if the estimated crank angle is a value in the range greater than the second end crank angle and less than 450 degrees, the vehicle control unit 94 decreases the opening of the throttle valve 48 from the current opening. Also, in this example, if the estimated crank angle is a value in the range greater than or equal to the second start crank angle and less than the second end crank angle, the vehicle control unit 94 maintains the opening of the throttle valve 48 at the current opening. Note that the opening of the throttle valve 48 is controlled not only for the illustrated second range but also for the first, third, and fourth ranges in the same manner as for the second range.

[0070] In the vehicle 1 of the first embodiment, by controlling the opening of the throttle valve 48 in this manner, it is possible to increase the probability that the estimated crank angle will fall within the specific crank angle range the next time the estimated crank angle is derived. In the vehicle 1 of the first embodiment, by repeating the process of deriving the estimated crank angle and the control of the opening of the throttle valve 48 in the specific stop control, it is possible to keep the estimated crank angle within the specific crank angle range. By performing such control in the vehicle 1 of the first embodiment, it is possible to stop the engine 10 so that the intake valve 28 and the exhaust valve 30 are in a valve overlap state when the engine 10 is stopped.

[0071] As described above, the vehicle 1 of the first embodiment includes a ventilation unit 46, specifically a pump 46A, that is provided in the intake flow path 40 and generates a gas flow. When a condition for stopping the engine 10 during operation is met, the processor 90 of the vehicle 1 of the first embodiment executes processing that includes performing specific stop control and opening the throttle valve 48 after the engine 10 has stopped. The specific stop control is control that stops the engine 10 so that the intake valve 28 and the exhaust valve 30 are both in a valve overlap state, which indicates that they are open.

[0072] As a result, in the vehicle 1 of the first embodiment, when the engine 10 is stopped, the gas flow path 56 from the intake port 44A of the intake flow path 40 to the exhaust port 54 of the exhaust flow path 42 is connected through the engine 10. Then, in the vehicle 1 of the first embodiment, the ventilation section 46 acts to exhaust the gas in the gas flow path 56 to the outside.

[0073] Therefore, in the vehicle 1 of the first embodiment, it is possible to suppress the accumulation of condensed water in the exhaust flow path 42. As a result, in the vehicle 1 of the first embodiment, it is possible to prevent condensed water from adhering to the exhaust sensor provided in the exhaust flow path 42, and to prevent the exhaust sensor from being damaged when the engine 10 is restarted.

[0074] In the vehicle 1 of the first embodiment, the intake valve 28 and the exhaust valve 30 are in a valve overlap state when the engine 10 is stopped, but the gas flow through the ventilation section 46 prevents gas in the exhaust flow path 42 from flowing back into the intake flow path 40. Therefore, in the vehicle 1 of the first embodiment, there is no situation in which the startability of the engine 10 is reduced when it is restarted.

[0075] (Second embodiment) 5 is a schematic diagram showing the configuration of a vehicle 200 of the second embodiment. Vehicle 200 differs from vehicle 1 of the first embodiment in that it has ventilation section 246 instead of ventilation section 46 and in the control content of vehicle control section 94, but the other configuration is common to vehicle 1 of the first embodiment. Therefore, for the sake of simplicity, a description of the points common to vehicle 1 of the first embodiment will be omitted. Note that in the second embodiment, vehicle 200 may be referred to as the host vehicle.

[0076] In the vehicle 200 of the second embodiment, the ventilation section 246 is provided in the exhaust flow path 42 between the muffler 52 and the exhaust port 54. The ventilation section 246 is configured to generate a gas flow in the exhaust flow path 42. The ventilation section 246 includes, for example, a running wind acquisition section 246A that acquires running wind to generate a gas flow in the exhaust flow path 42. The ventilation section 246 including the running wind acquisition section 246A is not limited to being provided between the muffler 52 and the exhaust port 54, and may be provided at any position in the exhaust flow path 42.

[0077] 6 is a cross-sectional view illustrating the configuration of the running wind acquisition unit 246A. The running wind acquisition unit 246A may be configured as a muffler cutter attached to the end of the exhaust flow path 42, for example.

[0078] The running wind acquisition section 246A has a main body section 250, a guide section 252, and an acquisition port 254. The main body section 250 is formed, for example, in a cylindrical shape, and is attached to the exhaust flow path 42 downstream of the muffler 52. The interior of the main body section 250 forms part of the exhaust flow path 42. The rear end of the main body section 250 is open and functions as an exhaust port 54 of the exhaust flow path 42.

[0079] The guide portion 252 is formed in a cylindrical shape extending outward from the outer peripheral surface of the main body portion 250 and diagonally forward of the vehicle 200. An acquisition port 254 penetrating the main body portion 250 is formed in front of the portion where the guide portion 252 is connected to the main body portion 250. The acquisition port 254 is formed in the lower portion of the main body portion 250.

[0080] When vehicle 200 travels forward, vehicle 200 is subjected to traveling wind directed from the front to the rear. Guide portion 252 of traveling wind acquisition portion 246A receives the traveling wind and guides it to main body portion 250. The traveling wind guided by guide portion 252 is introduced into main body portion 250 through acquisition port 254.

[0081] When the wind generated by running is introduced into the inside of the main body part 250, the flow velocity of the gas inside the main body part 250 becomes higher due to the acquired wind velocity, compared to the part of the exhaust flow path 42 upstream of the main body part 250. As a result, the pressure inside the main body part 250 becomes lower than the pressure in the part of the exhaust flow path 42 upstream of the main body part 250, and the gas upstream of the main body part 250 in the exhaust flow path 42 moves in a direction toward the inside of the main body part 250. This generates a flow of gas inside the exhaust flow path 42 from the upstream side to the downstream side.

[0082] Fig. 7 is a flowchart showing an example of the flow of operations of the vehicle control unit 94 in the second embodiment. The vehicle control unit 94 repeatedly performs the series of processes in Fig. 7 every time a predetermined interrupt timing occurs, which occurs every time a predetermined time elapses.

[0083] When a predetermined interrupt timing arrives, the vehicle control unit 94 determines whether the host vehicle is moving (S30). For example, the vehicle control unit 94 may acquire the current speed of the host vehicle from the speed sensor 64, and determine that the host vehicle is moving if the acquired speed is equal to or greater than a predetermined speed.

[0084] If it is determined that the vehicle is not moving (NO in S30), the vehicle control unit 94 ends the series of processes in FIG.

[0085] When it is determined that the vehicle is traveling (YES in S30), the vehicle control unit 94 determines whether or not a condition for stopping the engine 10 that is running is met (S10).

[0086] If it is determined that the condition for stopping the engine 10 in operation is not met (NO in S10), the vehicle control unit 94 ends the series of processes in FIG.

[0087] When it is determined that the condition for stopping the operating engine 10 is met (YES in S10), the vehicle control unit 94 performs specific stop control (S11). The specific stop control is control for stopping the engine 10 so that, when the engine 10 is stopped, a valve overlap state is established, which indicates that both the intake valve 28 and the exhaust valve 30 are open. The specific stop control in the second embodiment is the same as the specific stop control described in the first embodiment using FIGS. 3 and 4.

[0088] When the specific stop control is performed and the engine 10 is stopped, the intake port 24 communicates with the exhaust port 26 through the inside of the cylinder 22 in the engine 10 that is in the stopped state.

[0089] After the specific stop control is performed and the engine 10 is completely stopped, the vehicle control unit 94 opens the throttle valve 48 (S12) and ends the series of processes in Fig. 7. For example, the throttle valve 48 is set to the fully open state, but it is not limited to the fully open state and may be set to any opening that allows air to flow.

[0090] When the engine 10 is stopped in a valve overlap state and the throttle valve 48 is opened, the gas flow path 56 between the intake port 44A of the intake flow path 40 and the exhaust port 54 of the exhaust flow path 42 becomes connected through the engine 10.

[0091] As described above, the vehicle 200 of the second embodiment is provided with the traveling wind acquisition unit 246A, and it is determined that the vehicle is traveling. Therefore, as described in FIG. 6 , the traveling wind is acquired by the traveling wind acquisition unit 246A, and a flow from the upstream side to the downstream side is generated in the exhaust flow path 42. Then, because the exhaust flow path 42 is in communication with the intake flow path 40 through the inside of the cylinder 22, the flow generated by the traveling wind acquisition unit 246A is transmitted to the intake flow path 40 through the inside of the cylinder 22.

[0092] In this case, when the vehicle is traveling and the engine 10 is stopped, the traveling wind acquisition unit 246A acquires traveling wind, and gas in the gas flow path 56 that is connected thereto is discharged to the outside of the vehicle 200. For example, gas inside the exhaust flow path 42 is discharged to the outside.

[0093] As described above, the vehicle 200 of the second embodiment includes a ventilation unit 246, specifically, a running wind acquisition unit 246A, that is provided in the exhaust flow path 42 and acquires running wind to generate a gas flow in the exhaust flow path 42. When the vehicle is traveling and a condition for stopping the operating engine 10 is met, the processor 90 of the vehicle 200 of the second embodiment executes processing that includes performing specific stop control and opening the throttle valve 48 after the engine 10 is stopped. The specific stop control is control that stops the engine 10 so that the intake valve 28 and the exhaust valve 30 are both in a valve overlap state, which indicates that the valves are open.

[0094] As a result, in the vehicle 200 of the second embodiment, when the vehicle is traveling and the engine 10 is stopped, the gas flow path 56 from the intake port 44A of the intake flow path 40 to the exhaust port 54 of the exhaust flow path 42 is communicated through the engine 10. Then, in the vehicle 200 of the second embodiment, the ventilation section 246 acts to exhaust the gas in the gas flow path 56 to the outside.

[0095] Therefore, in the vehicle 200 of the second embodiment, similar to the first embodiment, it is possible to suppress the accumulation of condensed water in the exhaust flow path 42. As a result, in the vehicle 200 of the second embodiment, similar to the first embodiment, it is possible to prevent condensed water from adhering to the exhaust sensor provided in the exhaust flow path 42, and to prevent damage to the exhaust sensor when the engine 10 is restarted.

[0096] In the vehicle 200 of the second embodiment, the intake valve 28 and the exhaust valve 30 are in a valve overlap state when the engine 10 is stopped, but the gas flow caused by the ventilation section 246 prevents gas in the exhaust flow path 42 from flowing back into the intake flow path 40. Therefore, in the vehicle 200 of the second embodiment, there is no risk of a situation in which the startability of the engine 10 is reduced when it is restarted.

[0097] Furthermore, in the vehicle 200 of the second embodiment, the vehicle may stop traveling while the engine 10 is stopped and the ventilation unit 246 is discharging gas in the gas flow path 56 to the outside. Therefore, when the vehicle control unit 94 determines that the vehicle has stopped traveling, the vehicle control unit 94 may forcibly rotate the crankshaft 36 until the crank angle reaches a crank angle that does not result in a valve overlap state. In this way, in the vehicle 200 of the second embodiment, when the vehicle has stopped traveling and is no longer receiving wind due to traveling, communication between the intake flow path 40 and the exhaust flow path 42 is released, thereby preventing gas in the exhaust flow path 42 from flowing back into the intake flow path 40.

[0098] While the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such embodiments. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present invention.

[0099] For example, in the first embodiment, the ventilation section 46 including the pump 46A is provided, and in the second embodiment, the ventilation section 246 including the running wind acquisition section 246A is provided. The first and second embodiments may be combined to provide both the ventilation section 46 including the pump 46A and the ventilation section 246 including the running wind acquisition section 246A.

[0100] Furthermore, depending on the vehicle, an exhaust flow path valve capable of opening and closing the exhaust flow path 42 may be provided in the exhaust flow path 42. In such an example, the vehicle control unit 94 may open the exhaust flow path valve in addition to opening the throttle valve 48 after the specific stop control. In other words, the vehicle control unit 94 may open the valves provided in the intake flow path 40 and the exhaust flow path 42 after the specific stop control so as to communicate the gas flow path 56 from the intake port 44A of the intake flow path 40 to the exhaust port 54 of the exhaust flow path 42. [Explanation of symbols]

[0101] 1,200 vehicles 10 Engine 24 intake port 26 Exhaust port 28 Intake valve 30 Exhaust valve 40 intake passage 42 Exhaust flow path 46, 246 Ventilation section 46A Pump 48 Throttle valve 70 Control device 90 processors 92 memory 246A Running wind acquisition unit

Claims

1. The engine and an intake flow path through which air supplied to the engine flows; an exhaust flow path through which gas exhausted from the engine flows; a throttle valve provided in the intake passage; a ventilation section provided in at least one of the intake flow path and the exhaust flow path, which generates a gas flow; a control device; Equipped with The engine is an intake valve capable of opening and closing an intake port connected to the intake passage; an exhaust valve capable of opening and closing an exhaust port connected to the exhaust flow path; and The control device one or more processors; one or more memories coupled to the processor; and The processor: When a condition for stopping the engine in operation is met, performing specific stop control to stop the engine so that a valve overlap state is reached, which indicates that both the intake valve and the exhaust valve are open, when the engine is stopped; After the engine is stopped, the throttle valve is opened. A vehicle that performs processing including:

2. the ventilation unit includes a pump that is provided in the intake passage and is capable of sending air into the engine through the intake passage, The vehicle of claim 1 , wherein the processor executes a process including operating the pump after the engine is stopped.

3. The ventilation unit includes a running wind acquisition unit that is provided in the exhaust flow path and acquires running wind to generate a gas flow in the exhaust flow path, The processor: When the vehicle is traveling and the condition for stopping the engine that is running is met, performing the specific stop control; After the engine is stopped, the throttle valve is opened. The vehicle of claim 1 , wherein the vehicle performs a process including:

4. The specific stop control is deriving an estimated crank angle indicative of an estimate of the crank angle when the engine was stopped based on a current crank angle and a current crank angular velocity; controlling an opening degree of the throttle valve so that the estimated crank angle falls within a specific crank angle range that indicates a range of crank angles in which the intake valve and the exhaust valve are in the valve overlap state; 10. The vehicle of claim 1, comprising:

5. The specific stop control is When the estimated crank angle is out of the specific crank angle range in a direction in which the crank angle is smaller, the opening degree of the throttle valve is increased from a current opening degree; When the estimated crank angle is deviated from the specific crank angle range in a direction in which the crank angle is larger, the opening degree of the throttle valve is reduced from a current opening degree.

5. The vehicle of claim 4, comprising:

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