Vehicle

Abstract

To provide a vehicle capable of improving restartability by stopping a crank shaft at an intended position when stopping an internal combustion engine.SOLUTION: A vehicle (50) that drives a throttle valve (13) for adjusting output of an internal combustion engine (E) by using an actuator (14) and has an ignition switch (40) for turning on / off a power source includes: throttle valve control means (32) for performing driving control of the throttle valve (13); and use electric power detection means (31) for detecting use electric power of the vehicle (50). The throttle valve control means (32) performs throttle valve fully closing control for fully closing the throttle valve (13) if the use electric power detected by the use electric power detection means (31) is a predetermined value or smaller when the ignition switch (40) is turned off.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle, and more particularly to a vehicle that can improve startability when restarting an internal combustion engine as a drive source after it has been stopped. [Background technology]

[0002] BACKGROUND ART Conventionally, efforts have been made to improve the startability of an internal combustion engine, which serves as a drive source for a vehicle, when the engine is restarted after being stopped.

[0003] Patent Document 1 discloses a technology that improves restartability by estimating the stopping position of the crankshaft when the internal combustion engine is stopped, and then performing fuel injection and ignition control appropriate for this estimated stopping position when restarting the engine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-245105 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology of Patent Document 1 estimates the stopping position of the crankshaft when the internal combustion engine is stopped, and does not consider actively stopping the crankshaft at a desired position that improves restartability when the internal combustion engine is stopped.

[0006] An object of the present invention is to solve the problems of the conventional technology described above and to provide a vehicle that can improve restartability by stopping the crankshaft at a desired position when the internal combustion engine is stopped. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a vehicle (50) in which an actuator (14) drives a throttle valve (13) that adjusts the output of an internal combustion engine (E), and when the actuator (14) is not driven, the throttle valve (13) maintains an idling state using a mechanism that maintains a small open state, and which has an ignition switch (40) that turns a power source on and off. The vehicle (50) is provided with throttle valve control means (32) that controls the drive of the throttle valve (13), and power usage detection means (31) that detects power usage of the vehicle (50), and the throttle valve control means (32) has a first feature in that, when the ignition switch (40) is turned off, if the power usage detected by the power usage detection means (31) is equal to or less than a predetermined value, the throttle valve control means (32) performs throttle valve full closure control to fully close the throttle valve (13).

[0008] A second feature of the present invention is that the throttle valve full closure control is performed when the rotation speed of the internal combustion engine (E) becomes equal to or lower than a predetermined value that is lower than the idling rotation speed.

[0009] A third feature of the throttle valve control means (32) is that after the internal combustion engine (E) is stopped, the throttle valve control means (32) performs a spring check as a failure diagnosis by repeatedly fully opening and fully closing the throttle valve (13).

[0010] Furthermore, a fourth feature is that the throttle valve control means (32) brings the throttle valve (13) into a small open state by turning off the control of the actuator (14) after the spring check is completed. [Effects of the Invention]

[0011] According to a first feature, a vehicle (50) in which an actuator (14) drives a throttle valve (13) that adjusts the output of an internal combustion engine (E), and when the actuator (14) is not driven, the throttle valve (13) maintains an idling state using a mechanism that maintains a small open state, and which has an ignition switch (40) that turns a power source on and off, is provided with throttle valve control means (32) that controls the drive of the throttle valve (13), and power usage detection means (31) that detects power usage of the vehicle (50), and the throttle valve control means (32) is When the switch (40) is turned off, if the power usage detected by the power usage detection means (31) is equal to or less than a predetermined value, throttle valve full closure control is performed to fully close the throttle valve (13). Therefore, when the ignition switch is turned off while a large power load such as an air conditioner or a heater is in use, the absence of the power load reduces the load on the internal combustion engine, increasing the engine speed and causing the crankshaft to stop in a position that makes it easy to restart. However, if the ignition switch is turned off when the power load is low, the engine speed may continue to decrease, causing the crankshaft to stop in a position that makes it difficult to restart. In response to this, when the ignition switch is turned off when the power load is low, the throttle valve is fully closed to generate pumping loss, making it possible to stop the crankshaft in a position that makes it easy to restart.

[0012] According to the second feature, the throttle valve full closure control is performed when the rotation speed of the internal combustion engine (E) becomes equal to or less than a predetermined value that is lower than the idling rotation speed. Therefore, stable valve closure control can be performed in a situation where there is little rotation fluctuation due to external factors, and the crankshaft can be stopped at a desired position.

[0013] According to the third feature, the throttle valve control means (32) performs a spring check as a failure diagnosis by repeatedly fully opening and fully closing the throttle valve (13) after the internal combustion engine (E) is stopped. Therefore, by performing the spring check after the internal combustion engine is stopped, if there is a problem with the throttle valve drive mechanism, it is possible to notify the occupant by a display device or the like when the ignition switch is next turned on.

[0014] According to the fourth feature, after the spring check is completed, the throttle valve control means (32) turns off the control of the actuator (14) to bring the throttle valve (13) to a small open state. Therefore, after the spring check is completed, the throttle valve returns to a small open state and is ready for restart, thereby enabling a smooth restart of the internal combustion engine. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is an explanatory diagram showing a vehicle control device and its peripheral configuration. [Figure 2] 3 is a timing chart showing the combustion cycle and valve timing of the engine. [Figure 3] 4 is a flowchart showing a procedure for restartability improvement control according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] A preferred embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory diagram showing a control device 30 and its peripheral configuration for a vehicle 50 according to one embodiment of the present invention. A cylinder head 8 housing an intake valve IN and an exhaust valve EX is attached to the top of a cylinder 7 of an engine E, which is a four-stroke, parallel, two-cylinder internal combustion engine. A crank pulse rotor 4 that rotates synchronously with the crankshaft 3 is attached to the crankshaft 3. A total of 34 reluctors 5 are provided on the crank pulse rotor 4, arranged at 10-degree intervals, excluding one toothless portion H. A magnetic pickup-type pulse generator 1 outputs a pulse signal to the control device 30 each time it detects the passage of a reluctor 5.

[0017] An air cleaner box 9 that filters intake air is attached to one end of an intake pipe 19. An intake air temperature sensor 10 and an atmospheric pressure sensor 11 are provided in the air cleaner box 9. The intake pipe 19 is equipped with an air flow sensor 12 that measures the intake air volume, a butterfly throttle valve 13 driven by an actuator 14, a throttle valve opening sensor 16 that detects the rotation angle of the throttle valve 13, and a PB (intake air pressure) sensor 17 that detects the intake air pressure. An ignition device 20 is provided above the combustion chamber, and a fuel injection valve 18 is disposed in the intake pipe 19 downstream of the throttle valve 13. An oxygen concentration sensor 21 is attached to an exhaust pipe 22. In this embodiment, the throttle valve 13 that adjusts the output of the engine E is driven by the actuator 14, and the engine is configured to operate at idling speed by slightly opening the throttle valve 13. This embodiment includes a mechanism that maintains the throttle valve 13 in a slightly opened state when the actuator 14 is not driven.

[0018] Output signals from an ignition switch 40 and an electric power load 41 are input to the control device 30. After the ignition switch 40 is operated to turn on the power to the vehicle, when a starter switch (not shown) is operated, cranking of the crankshaft 3 is started by the starter motor 25. On the other hand, when the ignition switch 40 is turned off to turn off the power to the vehicle 1 while the engine E is running, the engine E stops.

[0019] The control device 30 includes a power usage detection means 31 that detects the power usage of the vehicle 50 due to power loads 41 such as an air conditioner and a heater, a throttle valve control means 32, a spring check execution means 33 that performs a fault diagnosis of the throttle valve drive mechanism after the engine E is stopped, an ignition device control means 34 that controls the ignition device 20 at a predetermined ignition timing, and a fuel injection device control means 35 that controls the fuel injection valve 18 at a predetermined injection timing.

[0020] When the ignition switch 40 is turned off to stop the engine E, the engine E normally stops after coasting with the throttle valve 13 kept at a small opening. However, if the power consumption of the vehicle 50 is below a predetermined threshold, the control device 30 of this embodiment is configured to fully close the throttle valve 13, causing a pumping loss and stopping the crankshaft 3 in a position that is favorable for restarting.

[0021] This corresponds to the fact that when the ignition switch 40 is turned off while an electric load 41 such as an air conditioner or heater is in use, the rotation speed of the engine E increases slightly due to the absence of the power generation load, and the crankshaft 3 stops in a position that makes it easier to restart. However, when the ignition switch 40 is turned off with a low power generation load, the rotation speed of the engine E decreases, and the crankshaft 3 may stop in a position that makes it harder to restart.

[0022] FIG. 2 is a timing chart showing the relationship between the combustion cycle of engine E and valve timing. FIG. 3 is a timing chart showing the valve timing of engine E. The combustion cycle of engine E consists of four strokes: compression, combustion, exhaust, and intake. Each stroke is determined based on the crank pulse output from pulse generator 1. Specifically, when the crank pulse detects missing tooth portion H of reluctor 5, the position from which a predetermined number of crank pulses are detected is determined as the reference position of crank pulse rotor 4, and one rotation of crankshaft 3 is divided into 34 crank stages according to the arrangement of reluctor 5. Then, based on the fluctuation state of the intake air pressure detected by PB sensor 17, it is determined whether the crankshaft 3 is in the first or second rotation of one cycle (720 degrees). Stroke determination is completed by dividing one cycle into 68 stages.

[0023] 4 is a flowchart showing the procedure for the restartability improvement control according to this embodiment. In step S1, the engine E is in operation. In step S2, it is determined whether the ignition switch 40 has been turned off, and if the determination in step S2 is affirmative, the process proceeds to step S3. If the determination in step S2 is negative, the process returns to the determination in step S2.

[0024] In step S3, the power usage detection means 31 detects the power usage of the vehicle 50. In the following step S4, it is determined whether the power usage is equal to or less than a predetermined threshold, and if the determination is affirmative, the process proceeds to step S5. In step S5, it is determined whether the engine rotation speed Ne is equal to or less than a predetermined threshold (e.g., 800 rpm) that is lower than the idling rotation speed, and if the determination is affirmative, the process proceeds to step S6.

[0025] In step S6, throttle valve full closure control is performed by the throttle valve control means 32 to fully close the throttle valve 13. This causes a pumping loss in the engine E, and allows the crankshaft 3 to stop at a desired angle that provides good restartability. In the following step S7, it is determined whether the engine E has stopped, and if the determination is affirmative, the process proceeds to step S8.

[0026] In step S8, a spring check is performed as a failure diagnosis in which the throttle valve 13 is repeatedly fully opened and fully closed. As a result, if there is any malfunction in the drive mechanism of the throttle valve 13, it is possible to notify the occupant by a display device or the like the next time the ignition switch 40 is turned on.

[0027] Then, in step S9, throttle valve control-off is performed, in which drive of actuator 14 is turned off and throttle valve 13 is slightly opened, thereby ending the series of controls. By turning throttle valve control-off, throttle valve 13 is slightly opened after the spring check is completed, and preparations for restart are made, thereby enabling a smooth restart of engine E. On the other hand, if a negative determination is made in step S4, that is, if the power usage of vehicle 50 exceeds a predetermined threshold when ignition switch 40 is turned off, it is determined that throttle valve full closure control is not necessary, and the process proceeds to step S10. In step S10, throttle valve control-off is performed, and the process proceeds to step S7.

[0028] As described above, the control device 30 according to the present invention drives the throttle valve 13, which adjusts the output of the engine E, with the actuator 14, and maintains an idling state using a mechanism that maintains the throttle valve 13 in a slightly open state when the actuator 14 is not driven, and is equipped with a throttle valve control means 32 that controls the drive of the throttle valve 13 and an electric power usage detection means 31 that detects the electric power usage of the vehicle 50, in a vehicle 50 having an ignition switch 40 that turns the power on and off. When the power usage detected by the power usage detection means 31 is below a predetermined threshold, throttle valve full closure control is performed to fully close the throttle valve 13. Therefore, if the ignition switch 40 is turned off while a large power load 41 such as an air conditioner or heater is in use, the engine E speed increases slightly due to the absence of the power generation load, and the crankshaft 3 stops at a position that makes it easy to restart. However, if the ignition switch 40 is turned off when the power generation load is low, the engine E speed may continue to decrease, and the crankshaft 3 may stop at a position that makes it difficult to restart. In response to this, if the ignition switch 40 is turned off when the power load is low, the throttle valve 13 is fully closed, causing a pumping loss, and it becomes possible to stop the crankshaft 3 at a position that makes it easy to restart.

[0029] The vehicle configuration, type of electric load, preferred angle at which the crankshaft is stopped when the engine is stopped, crankshaft angle range at which restartability decreases, threshold value of electric power usage as a condition for executing throttle valve full closure control, threshold value of engine speed as a condition for executing spring check, etc. are not limited to those in the above embodiment and can be modified in various ways. The control device according to the present invention can be applied to various vehicles that use a power unit including an internal combustion engine as a drive source, such as three-wheeled vehicles and four-wheeled vehicles in addition to motorcycles. [Explanation of symbols]

[0030] 50...vehicle, E...engine (internal combustion engine), 13...throttle valve, 14...actuator, 30...control device, 31...power usage detection means, 32...throttle valve control means, 40...ignition switch

Claims

1. A vehicle (50) in which a throttle valve (13) for adjusting the output of an internal combustion engine (E) is driven by an actuator (14), and when the actuator (14) is not driven, the throttle valve (13) maintains an idling state using a mechanism for maintaining a small open state, and which also has an ignition switch (40) for turning on and off a power source, a throttle valve control means (32) for controlling the actuation of the throttle valve (13); and a power usage detection means (31) for detecting the power usage of the vehicle (50), The vehicle is characterized in that the throttle valve control means (32) performs throttle valve full closure control to fully close the throttle valve (13) when the power usage detected by the power usage detection means (31) is equal to or less than a predetermined value when the ignition switch (40) is turned off.

2. 2. The vehicle according to claim 1, wherein the throttle valve full closure control is performed when the rotational speed of the internal combustion engine (E) becomes equal to or lower than a predetermined value that is lower than the idling rotational speed.

3. 3. The vehicle according to claim 1, wherein the throttle valve control means (32) performs a spring check as a fault diagnosis by repeating full opening and full closing of the throttle valve (13) after the internal combustion engine (E) has stopped.

4. 4. The vehicle according to claim 3, wherein the throttle valve control means (32) sets the throttle valve (13) to a small open state by turning off control of the actuator (14) after the spring check is completed.

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