vehicle

Abstract

To suppress adhesion of condensation water to a sensor.SOLUTION: A vehicle 1 comprises: a sensor 32 provided in an exhaust passage 30, an EGR passage 50 for recirculating exhaust gas from a portion of the exhaust passage 30 upstream of the sensor 32 to a portion of an intake passage 20 on a side of an engine 10; an openable / closable exhaust throttle 38 provided downstream of the sensor 32; an openable / closable intake throttle 24 provided in the intake passage 20; a supercharger 22 provided upstream of the intake throttle 24 in the intake passage 20; and a control unit that performs scavenging control to control the exhaust throttle 38, the intake throttle 24 and the supercharger 22 so that intake air flows into the exhaust passage 30 via the EGR passage 50 when the engine 10 is stopped.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In a vehicle engine, the exhaust gas from the engine flows through an exhaust passage, which is provided with, for example, a sensor for detecting NOx in order to purify the NOx in the exhaust gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-21457 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the engine is stopped, exhaust gas with a high moisture content remains in the exhaust passage. When the temperature drops, condensation occurs from the remaining exhaust gas, and the condensation may adhere to the sensor element. If condensation adheres to the sensor, it may accelerate the deterioration of the sensor.

[0005] The present invention has been made in consideration of these points, and has an object to suppress adhesion of condensed water to a sensor. [Means for solving the problem]

[0006] In one aspect of the present invention, there is provided a vehicle comprising an engine, an intake passage through which intake air to the engine flows, an exhaust passage through which exhaust air from the engine flows, a sensor provided in the exhaust passage, a return passage that recirculates the exhaust from a portion of the exhaust passage upstream of the sensor to a portion of the intake passage on the engine side, a first valve provided in the exhaust passage downstream of the sensor, a second valve provided in the intake passage, a supercharger provided in the intake passage upstream of the second valve, and a control unit that performs scavenging control to control the first valve, the second valve, and the supercharger so that intake air flows into the exhaust passage via the return passage when the engine is stopped.

[0007] The control unit may stop the scavenging control in response to an operation time having elapsed since the start of the scavenging control.

[0008] The vehicle may further include an acquisition unit that acquires an operating state of the engine before the engine is stopped, and the control unit may set the operating time in accordance with the operating state acquired by the acquisition unit.

[0009] The engine control system may further include an acquisition unit that acquires an amount of fuel injected into the engine before the engine is stopped, and the control unit may set the operation time in accordance with the amount of fuel injected.

[0010] Moreover, a third valve that can be opened and closed may be provided in the return passage, and the control unit may perform the scavenging control by opening the first valve, the second valve, and the third valve and operating the turbocharger when the engine is stopped.

[0011] The vehicle may further include an estimation unit that estimates a stop time for the engine to be stopped based on a situation around the vehicle when the engine is stopped, and the control unit may perform the scavenging control when the stop time estimated by the estimation unit is longer than a predetermined time.

[0012] The vehicle may further include a battery that supplies power to a motor that drives the vehicle, and the engine operates to charge the battery when the remaining charge of the battery is less than a first threshold, and the control unit performs the scavenging control when the remaining charge of the battery is greater than a second threshold that is greater than the first threshold.

[0013] The vehicle may further include a battery that supplies power to a motor that drives the vehicle, and a charging plug that is connected to an external charging device to charge the battery, and the control unit may perform the scavenging control when the charging plug is connected to the charging device.

[0014] The exhaust gas purification device may further include a purification device provided in the exhaust passage between the sensor and the first valve for purifying NOx from the exhaust gas, and the sensor may be a NOx sensor having a ceramic element. Effect of the Invention

[0015] According to the present invention, an effect of suppressing adhesion of condensed water to the sensor is achieved. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of a vehicle 1 according to one embodiment. [Diagram 2] FIG. 2 is a block diagram showing a detailed configuration of a control device 100. [Diagram 3] FIG. 4 is a schematic diagram showing the flow of intake air when scavenging control is performed. [Figure 4] 4 is a flowchart illustrating an example of the operation of the control device 100. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] <Vehicle configuration> Fig. 1 is a schematic diagram showing a configuration of a vehicle 1 according to one embodiment. The vehicle 1 is, for example, a truck. As shown in Fig. 1, the vehicle 1 has an engine 10, an intake passage 20, an exhaust passage 30, an EGR passage 50, a motor 60, a battery 62, a charging plug 64, and a control device 100.

[0018] The engine 10 is an internal combustion engine that burns and expands a mixture of fuel and intake air to generate power. The engine 10 is, for example, a diesel engine. A fuel injection unit that injects fuel into a combustion chamber, an intake valve that opens and closes an intake port, and an exhaust valve that opens and closes an exhaust port are provided in a cylinder head of the engine 10. The engine 10 functions as a power source for running the vehicle 1. The driving force generated by the engine 10 is transmitted to driving wheels (not shown) of the vehicle 1, thereby making it possible to run the vehicle 1. The engine 10 may also generate a driving force for running the vehicle 1 with the assistance of a driving force from a motor 60, which will be described later.

[0019] The intake passage 20 is a passage that introduces intake air into the engine 10. A supercharger 22 and an intake throttle 24 are provided in the intake passage 20.

[0020] The turbocharger 22 compresses intake air (air) and supplies it toward the engine 10. The turbocharger 22 is an electric turbocharger here, and compresses the intake air by driving a motor 23. Because the turbocharger 22 is electric, it can supercharge the intake air even when the engine 10 is stopped. The turbocharger 22 is provided upstream of the intake throttle 24 in the intake passage 20.

[0021] The intake throttle 24 is a valve that can be opened and closed. The flow rate of intake air directed to the engine 10 is adjusted by adjusting the opening degree of the intake throttle 24. The intake throttle 24 is located between the turbocharger 22 and the engine 10 in the intake passage 20.

[0022] The exhaust passage 30 is a passage that guides exhaust gas from the engine 10 to the atmosphere. The exhaust passage 30 is provided with a sensor 32, a urea water injection unit , an aftertreatment device , and an exhaust throttle .

[0023] The sensor 32 is provided in the exhaust passage 30 and is in contact with the exhaust gas flowing through the exhaust passage 30. The sensor 32 has a ceramic element. Here, the sensor 32 is a NOx sensor that detects the concentration of NOx in the exhaust gas. However, the sensor 32 is not limited to this, and may be an air-fuel ratio sensor that has a ceramic element.

[0024] The urea water injection unit 34 injects urea water into the exhaust passage 30. The urea water injection unit 34 is provided between the sensor 32 and the aftertreatment device 36. The urea water injected by the urea water injection unit 34 is hydrolyzed by the heat of the exhaust gas flowing through the exhaust passage 30, producing ammonia. The ammonia is used to cause a reduction reaction of NOx in the exhaust gas. The urea water injection unit 34 is provided downstream of the sensor 32 in the exhaust passage 30.

[0025] The aftertreatment device 36 is a purification device that purifies the exhaust gas flowing through the exhaust passage 30. Here, the aftertreatment device 36 purifies NOx in the exhaust gas. The aftertreatment device 36 is located between the sensor 32 and the exhaust throttle 38 in the exhaust passage 30. The aftertreatment device 36 has an SCR catalyst 37a and an ASC 37b.

[0026] The SCR catalyst 37a is a reduction catalyst that promotes the reduction reaction between ammonia and NOx. The SCR catalyst 37a adsorbs ammonia generated from the urea water injected by the urea water injection unit 34. The SCR catalyst 37a reduces NOx to harmless nitrogen and water using the adsorbed ammonia, thereby reducing the emission of NOx. The ASC 37b is a catalyst that decomposes the ammonia desorbed from the SCR catalyst 37a. The ASC 37b converts ammonia into nitrogen or water, for example, thereby suppressing the emission of ammonia.

[0027] The exhaust throttle 38 is a valve that can be opened and closed. The flow rate of the exhaust gas led to the atmosphere is adjusted by adjusting the opening degree of the exhaust throttle 38. The exhaust throttle 38 is provided downstream of the sensor 32 in the exhaust passage 30.

[0028] The EGR passage 50 connects the exhaust passage 30 and the intake passage 20. The EGR passage 50 is a recirculation passage that recirculates a portion of the exhaust gas (also called EGR gas) to the intake passage 20. The EGR passage 50 recirculates the EGR gas from a portion of the exhaust passage 30 upstream of the sensor 32 to a portion of the intake passage 20 closer to the engine 10 than the intake throttle 24. The EGR gas that flows through the EGR passage 50 joins the intake passage 20 between the intake throttle 24 and the engine 10, and is led to the engine 10.

[0029] The EGR passage 50 is provided with an EGR valve 52. The EGR valve 52 is a valve that can be opened and closed. The flow rate of EGR gas flowing through the EGR passage 50 is adjusted by adjusting the opening degree of the EGR valve 52. Note that, although the EGR valve 52 is provided in the EGR passage 50 in the above description, the present invention is not limited thereto, and the EGR valve 52 may not be provided. In this embodiment, the exhaust throttle 38 corresponds to the first valve, the intake throttle 24 corresponds to the second valve, and the EGR valve 52 corresponds to the third valve.

[0030] The motor 60 functions as a power source for running the vehicle 1. That is, the motor 60 runs the vehicle 1 in place of the engine 10. The motor 60 can rotate the crankshaft of the engine 10 even in a state in which fuel is not injected into the engine 10.

[0031] The battery 62 is a storage battery that can be charged and discharged. The battery 62 supplies electric power to the motor 60 that drives the vehicle 1. The battery 62 can also supply electric power to the motor 23 that operates the turbocharger 22.

[0032] The charging plug 64 is a plug for charging the battery 62. When the vehicle 1 is a plug-in hybrid vehicle, the charging plug 64 is connected to an external charging device, whereby power is supplied from the charging device to the battery 62, thereby charging the battery 62.

[0033] The control device 100 controls the operation of the vehicle 1. For example, the control device 100 controls the opening and closing of the intake throttle 24, the exhaust throttle 38, and the EGR valve 52. The control device 100 also causes the supercharger 22 to supercharge the intake air.

[0034] Incidentally, when the engine 10 is stopped, exhaust gas with a high moisture concentration remains in the exhaust passage 30. The high moisture concentration in the exhaust gas is due to the presence of hydrogen in the fuel before combustion. When the temperature of the exhaust gas subsequently drops, condensation may occur from the exhaust gas remaining in the exhaust passage 30, and the condensation may adhere to the element of the sensor 32. If the condensation water adheres to the sensor 32, the deterioration of the sensor 32 may be accelerated. For example, if the sensor 32 generates heat when it starts operating, the condensation water adhered to the sensor 32 may evaporate instantaneously, damaging the sensor 32 and accelerating its deterioration. In response to this, the control device 100 of this embodiment, which will be described in detail later, performs scavenging control to cause the intake air in the intake passage 20 to flow through the EGR passage 50 into the exhaust passage 30 when the engine 10 is stopped. As a result, after the engine 10 is stopped, the flow of the intake air causes the exhaust gas to be discharged from the exhaust passage 30, so that it is possible to suppress the generation of condensed water in the exhaust passage 30. Although the intake air remains in the exhaust passage 30, the intake air contains less moisture than the exhaust gas, so that condensed water is less likely to occur.

[0035] <Detailed configuration of the control device> 2 is a block diagram showing a detailed configuration of the control device 100. The control device 100 includes a storage unit 110 and a control unit 120.

[0036] The storage unit 110 includes, for example, a Read Only Memory (ROM) and a Random Access Memory (RAM). The storage unit 110 stores programs to be executed by the control unit 120 and various data.

[0037] The control unit 120 is a processor such as a CPU (Central Processing Unit). The control unit 120 executes a program stored in the storage unit 110 to function as an acquisition unit 122, an estimation unit 123, a valve control unit 124, a supercharging control unit 125, and a scavenging control unit 127.

[0038] The acquisition unit 122 acquires the operating state of the engine 10. For example, the acquisition unit 122 acquires the rotation speed, torque, and the like of the engine 10 from the engine detection unit 80. The engine detection unit 80 includes a speed sensor that detects the rotation speed of the engine 10 and a torque sensor that detects the torque of the engine 10. The engine detection unit 80 also detects whether an ignition switch of the engine 10 is on or off.

[0039] The acquisition unit 122 acquires the operating state of the engine 10 before the engine 10 is stopped. For example, the acquisition unit 122 acquires the amount of fuel injected into the engine 10 before the engine 10 is stopped. The amount of fuel injection can be identified, for example, from a control amount instructed by the control device 100 to the fuel injection unit.

[0040] The estimation unit 123 estimates the stop time for the engine 10 to stop. The estimation unit 123 estimates the stop time for the engine 10 to stop from the situation around the vehicle 1 when the engine 10 stops. For example, if the vehicle 1 stops in the parking lot at night, the estimation unit 123 estimates that the stop time is the time from the time the vehicle 1 stops to the next morning.

[0041] The valve control unit 124 controls the opening and closing of the intake throttle 24, the exhaust throttle 38, and the EGR valve 52. For example, when performing intake scavenging control, the valve control unit 124 opens the intake throttle 24, the exhaust throttle 38, and the EGR valve 52. Here, the valve control unit 124 opens the intake throttle 24, the exhaust throttle 38, and the EGR valve 52 simultaneously.

[0042] The supercharging control unit 125 controls the operation of the supercharger 22. The supercharging control unit 125 supercharges the intake air by driving the motor 23 to operate the supercharger 22. For example, the supercharging control unit 125 operates the supercharger 22 when performing scavenging control of the intake air. By operating the supercharger 22 during scavenging control, the intake air in the intake passage 20 is more likely to flow into the exhaust passage 30.

[0043] In this embodiment, the valve control unit 124 and the supercharging control unit 125 cooperate with each other to function as a scavenging control unit 127 that performs scavenging control. When the engine 10 is stopped, the scavenging control unit 127 performs scavenging control to direct the intake air in the intake passage 20 to the exhaust passage 30 via the EGR passage 50. The scavenging control unit 127 performs scavenging control immediately after the engine 10 is stopped.

[0044] FIG. 3 is a schematic diagram showing the flow of intake air when scavenging control is performed. The scavenging control unit 127 opens the intake throttle 24, the exhaust throttle 38, and the EGR valve 52 in order to perform scavenging control. Here, the scavenging control unit 127 fully opens the intake throttle 24, the exhaust throttle 38, and the EGR valve 52. Then, the scavenging control unit 127 operates the motor 23 to cause the supercharger 22 to supercharge the intake air. As a result, the intake air compressed by the supercharger 22 flows in the order of the intake passage 20, the EGR passage 50, and the exhaust passage 30, as shown by the arrows in FIG. 3. As the intake air flows, the exhaust gas that has remained in the exhaust passage 30 until then is discharged to the atmosphere. In other words, as the intake air flows, the exhaust gas that has remained in the exhaust passage 30 until then is replaced with the intake air. As a result, the exhaust gas does not remain in the exhaust passage 30, and the generation of condensed water in the exhaust passage 30 can be suppressed. Although intake air remains in the exhaust passage 30 instead of the exhaust air, the moisture concentration in the intake air is lower than that in the exhaust air, so condensed water is less likely to occur. Furthermore, the exhaust control unit 127 stops the turbocharger 22 to stop scavenging when a predetermined operation time has elapsed since the start of scavenging control. This makes it possible to prevent the turbocharger 22 from operating for a long period of time when the vehicle 1 is stopped, resulting in a decrease in the power of the battery 62. Note that the predetermined operation time may be dynamically set depending on the state of the vehicle 1 and the operating state of the engine 10.

[0045] The amount of exhaust from the engine 10 changes depending on the operating state of the engine 10 (e.g., high revolution or low revolution), and the amount of remaining exhaust after the engine 10 is stopped also changes. Therefore, the scavenging control unit 127 changes the operation time of the turbocharger 22 during scavenging control according to the operating state of the engine 10 acquired by the acquisition unit 122. By changing the operation time of the turbocharger 22 during scavenging control in this manner, it becomes easier to discharge the exhaust remaining in the exhaust passage 30 when the engine 10 is stopped by intake air.

[0046] For example, the scavenging control unit 127 changes the operation time of the turbocharger 22 during scavenging control according to the amount of fuel injected into the engine 10. Specifically, the scavenging control unit 127 lengthens the operation time of the turbocharger 22 during scavenging control as the amount of fuel injected into the engine 10 increases. As the amount of fuel injected increases, the moisture concentration in the exhaust gas increases, increasing the risk of condensation water generation. Therefore, by lengthening the operation time of the turbocharger 22 during scavenging control as the amount of fuel injected increases, exhaust gas can be discharged more reliably, and the generation of condensation water can be effectively suppressed.

[0047] The scavenging control unit 127 performs scavenging control when the stop time of the engine 10 estimated by the estimation unit 123 is longer than a predetermined time. When the stop time of the engine 10 is long, the temperature in the exhaust passage 30 is likely to drop, and condensation water is likely to occur. Therefore, when the stop time is long, the scavenging control unit 127 performs scavenging control before the temperature drops, thereby suppressing the generation of condensation water, and as a result, it is possible to suppress the adhesion of condensation water to the sensor 32. For example, the predetermined time is a value obtained in advance by experiment or simulation as the time at which the temperature change after the engine 10 is stopped reaches a predetermined temperature difference. For example, the predetermined time is 5 hours.

[0048] The predetermined time is stored in the storage unit 110. The predetermined time is associated in advance with the environmental temperature of the vehicle 1 and the engine 10, the driving state of the engine 10 before the engine is stopped, and the like. The greater the fuel injection amount of the engine 10 before the engine is stopped, the shorter the predetermined time is set. This is because the greater the fuel injection amount of the engine 10 before the engine is stopped, the greater the amount of moisture contained in the exhaust gas, and there is a concern that condensation water will occur in a short time. In addition, the lower the environmental temperature before the engine is stopped, the shorter the predetermined time is set. This is because the lower the environmental temperature before the engine is stopped, the faster the temperature drop in the exhaust passage 30 progresses, and there is a concern that condensation water will occur in a short time. In addition, the predetermined time may be set according to the season, altitude, and the like.

[0049] Furthermore, the scavenging control unit 127 may perform scavenging control every time the engine 10 is stopped, regardless of the stop time of the engine 10 estimated by the estimation unit 123. This makes it possible to suppress exhaust gas from remaining in the exhaust passage 30 after the engine 10 is stopped, thereby suppressing the generation of condensed water.

[0050] The vehicle 1 can switch between running with the engine 10 and running with the motor 60 depending on the remaining charge of the battery 62. For example, when the remaining charge of the battery 62 is less than a first threshold, the vehicle 1 runs with the engine 10 to charge the battery 62. On the other hand, when the remaining charge of the battery 62 is greater than a second threshold that is greater than the first threshold, the vehicle 1 runs with the motor 60 with the engine 10 stopped. When switching from running with the engine 10 to running with the motor 60, exhaust gas remains in the exhaust passage 30 because the vehicle had been running with the engine 10 until then. The scavenging control unit 127 performs scavenging control to discharge the exhaust gas remaining in the exhaust passage 30 when running with the motor 60. That is, the scavenging control unit 127 performs scavenging control when the remaining charge of the battery 62 is greater than a second value. As a result, when the vehicle 1 runs with the motor 60, the exhaust gas remaining in the exhaust passage 30 until then is discharged, thereby suppressing the generation of condensed water in the exhaust passage 30. The second value is set in advance, and is, for example, a value that allows the vehicle 1 to run for about one hour using the motor 60. The first value and the second value are stored in the storage unit 110.

[0051] The scavenging control unit 127 performs scavenging control when the charging plug 64 is connected to an external charging device. The charging plug 64 is often connected to the charging device after the vehicle 1 has finished traveling, and the time for which the engine 10 is stopped is likely to be long. This raises concerns that the temperature of the exhaust passage 30 will drop and condensation will occur. For this reason, by having the scavenging control unit 127 perform scavenging control when the charging plug 64 is connected to the charging device, it is possible to suppress the subsequent generation of condensation in the exhaust passage 30.

[0052] <Example of control device operation> Fig. 4 is a flowchart for explaining an example of the operation of the control device 100. The process shown in the flowchart of Fig. 4 starts when the engine 10 is operating.

[0053] First, the control device 100 determines whether or not the engine 10 has stopped (step S102). For example, when the engine detection unit 80 detects that the ignition switch is turned off, the control device 100 determines that the engine 10 has stopped.

[0054] When it is determined in step S102 that the engine 10 has stopped (Yes), the acquisition unit 122 acquires the operating state of the engine 10 before the engine 10 was stopped (step S104). For example, the acquisition unit 122 acquires the amount of fuel injected into the engine 10 before the engine 10 was stopped.

[0055] Next, the scavenging control unit 127 sets the operation time of the turbocharger 22 during scavenging control based on the operation state of the engine 10 before the engine 10 is stopped (step S106). For example, the scavenging control unit 127 sets the operation time of the turbocharger 22 longer as the fuel injection amount before the engine 10 is stopped is larger.

[0056] Next, the scavenging control unit 127 executes scavenging control (step S108). That is, the scavenging control unit 127 opens the intake throttle 24, the exhaust throttle 38, and the EGR valve 52, and operates the turbocharger 22 to direct the intake air in the intake passage 20 to the exhaust passage 30 via the EGR passage 50. At this time, the scavenging control unit 127 operates the turbocharger 22 for the operation time set in step S106. That is, the scavenging control unit 127 stops the scavenging control in response to the lapse of the operation time set in step S106. By performing the scavenging control in this manner, the exhaust gas remaining in the exhaust passage 30 is discharged to the atmosphere when the intake air flows through the exhaust passage 30.

[0057] <Effects of this embodiment> In the vehicle 1 of the above-described embodiment, when the engine 10 is stopped, scavenging control is performed to control the exhaust throttle 38, the intake throttle 24, and the turbocharger 22 so that the intake air in the intake passage 20 flows into the exhaust passage 30 via the EGR passage 50. As a result, when the engine 10 is stopped, the intake air flowing through the exhaust passage 30 expels the exhaust gas remaining in the exhaust passage 30. This makes it possible to suppress the generation of condensed water in the exhaust passage 30, and as a result, the adhesion of condensed water to the sensor 32 in the exhaust passage 30 can be suppressed.

[0058] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination combines the effect of the original embodiment. [Explanation of symbols]

[0059] 1 vehicle 10 Engine 20 Intake passage 22 Turbocharger 24 Intake throttle 30 Exhaust passage 32 Sensors 38 Exhaust throttle 50 EGR passage 52 EGR valve 122 Acquisition Department 123 Estimation Department 127 Scavenging control section

Claims

1. The engine, an intake passage through which intake air flows to the engine; an exhaust passage through which exhaust gas from the engine flows; A sensor provided in the exhaust passage; a return passage for returning the exhaust gas from a portion of the exhaust passage upstream of the sensor to a portion of the intake passage on the engine side; a first valve provided in the exhaust passage downstream of the sensor; A second valve provided in the intake passage; a supercharger provided in the intake passage upstream of the second valve; a control unit that performs scavenging control to control the first valve, the second valve, and the turbocharger so as to cause intake air to flow into the exhaust passage via the return passage when the engine is stopped; A vehicle comprising:

2. The control unit stops the scavenging control in response to an operation time having elapsed since the start of the scavenging control.

2. The vehicle of claim 1.

3. An acquisition unit that acquires an operating state of the engine before the engine is stopped, The control unit sets the operation time in accordance with the operation state acquired by the acquisition unit.

3. A vehicle as claimed in claim 2.

4. An acquisition unit that acquires a fuel injection amount injected into the engine before the engine is stopped, The control unit sets the operation time in accordance with the fuel injection amount.

3. A vehicle as claimed in claim 2.

5. a third valve that can be opened and closed is provided in the return passage, The control unit opens the first valve, the second valve, and the third valve and operates the turbocharger to perform the scavenging control when the engine is stopped.

2. The vehicle of claim 1.

6. An estimation unit that estimates a stop time of the engine from a situation around the vehicle when the engine is stopped, The control unit performs the scavenging control when the stop time estimated by the estimation unit is longer than a predetermined time.

2. The vehicle of claim 1.

7. The vehicle further includes a battery that supplies power to a motor that drives the vehicle. The engine operates to charge the battery when the remaining charge of the battery is less than a first threshold value; The control unit performs the scavenging control when the remaining amount of the battery is greater than a second threshold value that is greater than the first threshold value.

2. The vehicle of claim 1.

8. a battery that supplies power to a motor that drives the vehicle; a charging plug for connecting to an external charging device to charge the battery; The control unit performs the scavenging control when the charging plug is connected to the charging device.

2. The vehicle of claim 1.

9. a purification device provided in the exhaust passage between the sensor and the first valve for purifying NOx from the exhaust gas, The sensor is a NOx sensor having a ceramic element.

2. The vehicle of claim 1.

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