Internal combustion engine preheating device

Abstract

The present invention relates to an internal combustion engine preheating device capable of effectively preheating an engine. The internal combustion engine preheating device (10) includes: an aftertreatment device (12); a heater (11) provided upstream of the aftertreatment device on an exhaust passage; a circulation passage (p7) in which air passing through the aftertreatment device (12) is sent back to an upstream side of the heater (11); an air pump (14) that is a blower that sends air heated by the heater (11) to the aftertreatment device (12); a coolant flow path (L); a heat exchanger (13); and a control device (15) that controls operation of the heater (11) and the blower (14), the control device (15) causing the heater (11) and the air pump (14) to operate and causing air heated by the heater (11) to be supplied to the aftertreatment device (12) and the heat exchanger (13) in a state in which an engine (6) is stopped.

Description

TECHNICAL FIELD

[0001] The present application relates to an internal combustion engine preheating device. BACKGROUND

[0002] Japanese Patent Application Publication No. 2010-112296 proposes warming up a catalyst to activate the catalyst. SUMMARY

[0003] Engines of vehicles such as HEVs (Hybrid Electric Vehicles) or PHEVs (Plug-in Hybrid Electric Vehicles) do not operate in a state where the motor thereof is driven. By warming up the catalyst while the engine is stopped, exhaust gas can be reduced well even after the motor-driven state is switched to the engine-driven state. On the other hand, there is a problem that the temperature of the engine is low and the operation performance of the engine is reduced immediately after the switch to the engine-driven state.

[0004] The present application has been made in view of these problems, and it is an object thereof to provide an internal combustion engine preheating device that can effectively preheat an engine while a catalyst is warmed up by a heater at the time of engine stop.

[0005] One aspect of the present application provides an internal combustion engine preheating device including: an aftertreatment device having a catalyst and removing nitrogen oxides in exhaust gas through an exhaust passage through which exhaust gas discharged from an engine passes; a heater provided on the exhaust passage upstream of the aftertreatment device; a circulation passage in which air passing through the aftertreatment device is sent back to an upstream side of the heater; a blower that sends air heated by the heater to the aftertreatment device; a coolant flow path in which coolant of the engine flows; a heat exchanger that warms up the coolant in the coolant flow path by heat exchange between the heated air passing through the aftertreatment device and the coolant; and a control device that controls operation of the heater and the blower, wherein in a state where the engine is stopped, the control device operates the heater and the blower and supplies air heated by the heater to the aftertreatment device and the heat exchanger.

[0006] The control device can operate the heater and the blower in a case where the temperature of the catalyst in the aftertreatment device is equal to or lower than a predetermined threshold value.

[0007] The heat exchanger can be provided on the exhaust passage, the circulation passage can include a first branch passage branched from the exhaust passage at a portion located upstream of the heat exchanger, and the internal combustion engine warm-up device can further include a first valve provided at the portion where the first branch passage is branched from the exhaust passage and switched between a state in which the heated air flows through the first branch passage and a state in which the heated air flows through the exhaust passage, and the control device can control the first valve and cause the heated air to flow through the first branch passage and circulate in the circulation passage when the temperature of the engine exceeds the predetermined threshold in the state in which the heated air is supplied to the aftertreatment device and the heat exchanger.

[0008] The control device can control the first valve and cause the heated air to flow through only the first branch passage and circulate in the circulation passage when the temperature of the engine exceeds the predetermined threshold in the state in which the heated air is supplied to the aftertreatment device and the heat exchanger.

[0009] The heat exchanger can be provided on the exhaust passage, the circulation passage can include a second branch passage branched from the exhaust passage at a portion located downstream of the heat exchanger, and the internal combustion engine warm-up device can further include a second valve provided at the portion where the second branch passage is branched from the exhaust passage and switched between a state in which the heated air flows through the second branch passage and a state in which the heated air flows through the exhaust passage, and the control device can control the first valve and the second valve, switch the first valve to the state in which the heated air flows through the exhaust passage, switch the second valve to the state in which the heated air flows through the second branch passage before causing the heater and the blower to operate, and then cause the heater and the blower to operate, thereby supplying the heated air to the aftertreatment device and the heat exchanger.

[0010] The circulation passage can be a first circulation passage and located downstream of the turbocharger and upstream of the heater, the air that has passed through the aftertreatment device is sent back to a position on the exhaust passage in the first circulation passage, and an air pump can be provided on the first circulation passage as the blower.

[0011] The circulation passage can be a second circulation passage, the air that has passed through the aftertreatment device is sent back to an intake passage of the turbocharger in the second circulation passage, and the heat exchanger can be a low-pressure EGR cooler provided on the second circulation passage.

[0012] The present application has an advantage in that an internal combustion engine warm-up device capable of effectively warming up an engine by warming up a catalyst with a heater in a state in which the engine is stopped can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a view showing a configuration of an internal combustion engine in an embodiment according to the present application.

[0014] Figure 2is a flowchart of a warm-up operation performed by a warm-up device in an engine stop state.

[0015] Figure 3 is a view showing the configuration of an internal combustion engine in another embodiment of the application.

[0016] Explanation of Reference Numerals

[0017] 1: Air cleaner

[0018] 2: Turbocharger

[0019] 3: First charge air cooler

[0020] 4: Electric supercharger

[0021] 5: Second charge air cooler

[0022] 6: Engine

[0023] 7: EGR pipe section

[0024] 7a: EGR cooler

[0025] 10: Warm-up device

[0026] 10A: Warm-up device

[0027] 11: Heater

[0028] 12: Aftertreatment device

[0029] 13: Heat exchanger

[0030] 14: Air pump

[0031] 15: Control device

[0032] 16: LP-EGR cooler

[0033] 100: Internal combustion engine

[0034] ECU: Engine

[0035] L: Coolant flow path

[0036] p1: Intake passage

[0037] p2: Passage

[0038] p3: Passage

[0039] p4: Passage

[0040] p5: Passage

[0041] p6: Exhaust passage

[0042] p7: Circulation passage

[0043] p7-1: first branch passage

[0044] p7-2: second branch passage

[0045] p7-3: passage

[0046] p8: circulation passage

[0047] T1: temperature sensor

[0048] T2: temperature sensor

[0049] V1: first valve

[0050] V2: second valve

[0051] Va: valve

[0052] Vb: valve

[0053] Vc: valve DETAILED DESCRIPTION

[0054] <First Embodiment>

[0055] (Overview of Internal Combustion Engine 100)

[0056] Figure 1 is a diagram showing the configuration of an internal combustion engine 100 in an embodiment according to the present application. Figure 1 The arrows in indicate air flow. As an example, the internal combustion engine 100 is an internal combustion engine mounted on a vehicle such as an HEV (Hybrid Electric Vehicle) or a PHEV (Plug-in Hybrid Electric Vehicle).

[0057] The internal combustion engine 100 mainly includes an air cleaner 1, a turbocharger 2, a first charge air cooler 3, an electric supercharger 4, a second charge air cooler 5, an engine 6, an EGR pipe section 7, and a preheating device 10.

[0058] Since the air flow when the engine 6 is operated is basically similar to typical air flow in an internal combustion engine of this type, the air flow is simply explained. During operation of the engine 6, air taken in by the vehicle passes through the air cleaner 1, the turbocharger 2, the first charge air cooler 3, the electric supercharger 4, and the second charge air cooler 5, and is supplied to the engine 6. Part of the exhaust gas discharged from the engine 6 is sent back to the air supply side of the engine 6 through the EGR pipe section 7. Another part of the exhaust gas discharged from the engine 6 passes through the turbocharger 2, and then flows into the preheating device 10.

[0059] As described in detail later, one of the features of the internal combustion engine 100 according to the present embodiment is that the preheating device 10 is formed on the exhaust side of the engine 6. When the engine 6 is stopped, the preheating device 10 operates the heater 11 and the air pump 14, and supplies air heated by the heater 11 to the aftertreatment device 12 and the heat exchanger 13. Thereby, the catalyst in the aftertreatment device 12 is warmed up. In addition, the engine coolant in the coolant flow path L is also warmed up, and therefore the engine 6 is also preheated.

[0060] According to such a configuration, it is possible to warm up the catalyst in the aftertreatment device 12 while the engine 6 is stopped, and raise the temperature of the catalyst to the activation temperature. In addition, by warming up the engine coolant using the energy for warming up the catalyst in the aftertreatment device 12, it is possible to effectively preheat the engine 6.

[0061] (Configuration of each part)

[0062] Each part of the internal combustion engine 100 will be described below. The air cleaner 1 is a filter that removes foreign matter in air taken into the engine 6. Air taken in from the air cleaner 1 is supplied to the turbocharger 2 through an intake passage pl.

[0063] The turbocharger 2 rotates a turbine using exhaust gas of the engine 6 to thereby compress air taken in through the intake passage pl. By supplying air compressed by the turbocharger 2 to the engine 6, the torque generated in one combustion stroke of the engine 6 is increased.

[0064] The first charge air cooler 3 cools air that has been compressed by the turbocharger 2 and has an increased temperature. As the air is cooled, the density of air taken into the engine 6 is increased.

[0065] The electric supercharger 4 is a device that supplies compressed air compressed by driving force of an unillustrated motor to the engine 6. The electric supercharger 4 is provided on a passage p2 connecting the first charge air cooler 3 and the second charge air cooler 5. In a state where the electric supercharger 4 does not supply compressed air to the engine 6, the electric supercharger 4 inhibits air from passing through the electric supercharger 4. Therefore, in this state, air is supplied to the second charge air cooler 5 not through the passage p2 but through a passage p3 that is a bypass passage. A valve Va is provided on the passage p3. The valve Va is, for example, an electromagnetic valve that switches the open / close state of the passage p3. Specifically, the valve Va switches the open / close state of the passage p3 between a state where air passes through the passage and a state where air does not pass through the passage.

[0066] In a state where the engine 6 is stopped, the electric supercharger 4 supplies compressed air to the exhaust side of the engine 6 through the EGR pipe section 7. An example in which the electric supercharger 4 functions as a blower of the preheating device 10 is described in the second embodiment.

[0067] The second charge air cooler 5 cools air taken in by the engine 6. For example, the engine 6 generates driving force by converting reciprocating motion of a cylinder caused by combustion of liquid fuel such as light oil into rotational force. Figure 1 An example of a 4-cylinder diesel engine is shown.

[0068] The EGR pipe section 7 is a structural portion for sending part of exhaust gas of the engine 6 back to the air supply side of the engine 6. The EGR pipe section 7 has a passage p4, a passage p5, an EGR cooler 7a, a valve Vb, and a valve Vc. The passage p4 and the passage p5 are provided in parallel, connecting the air supply side and the exhaust side of the engine 6.

[0069] The EGR cooler 7a is provided on the passage p4, and cools exhaust gas sent back from the exhaust side of the engine 6 to the air supply side. The valve Vb is provided on the passage p5. For example, the valve Vb is a solenoid valve, switching an open / close state of the passage p5 between a state in which air passes through the passage p5 and a state in which air does not pass through the passage p5. The valve Vc switches an open / close state of the passage in the EGR pipe section 7 between a state in which air passes through the passage and a state in which air does not pass through the passage.

[0070] By sending part of exhaust gas back to the intake side of the engine 6 through the EGR pipe section 7 thus configured, the maximum temperature at the time of combustion in the engine 6 is reduced. As a result, the amount of production of nitrogen oxides is reduced. In a state in which the engine 6 is stopped, compressed air from the electric supercharger 4 can be supplied to the exhaust side of the engine 6 through the passage p5.

[0071] (Regarding the Preheating Device 10)

[0072] The preheating device 10 mainly has an exhaust passage p6, a heater 11, an aftertreatment device 12, a circulation passage p7, a first valve V1, a second valve V2, a heat exchanger 13, a coolant flow path L, an air pump 14, and a control device 15.

[0073] The exhaust passage p6 is a passage in which exhaust gas from the engine 6 flows. The heater 11, the aftertreatment device 12, and the heat exchanger 13 are provided in this order from the upstream side on the exhaust passage p6. A terminal portion of the exhaust passage p6 is exposed to the atmosphere, and exhaust gas that has passed through the turbocharger 2 is discharged from the terminal portion of the exhaust passage p6 to the atmosphere.

[0074] The heater 11 heats air flowing in the exhaust passage p6. The heater 11 is located upstream of the aftertreatment device 12 on the exhaust passage p6. As an example, the heater 11 is an electric heating coil heater. The heater 11 is driven by electric power from an unillustrated power source. The operation of the heater 11 is controlled by the control device 15. The heater 11 heats air to a temperature sufficient such that, when the heated air passes through the aftertreatment device 12, a catalyst is warmed to a temperature equal to or higher than an activation temperature of the catalyst.

[0075] The post-processing device 12 has a catalyst and removes nitrogen oxides from the exhaust gas in the exhaust passage p6. Figure 1 In the example shown, the aftertreatment device 12 includes a DOC 12 a and an SCR 12 b .

[0076] The DOC (diesel oxidation catalyst) 12a includes a precious metal catalyst, and oxidizes unburned gas in the exhaust gas from the engine 6. The DOC 12a oxidizes hydrocarbons, carbon monoxide, and nitrogen oxides.

[0077] The SCR (Selective Catalytic Reduction) 12b removes nitrogen oxides in the exhaust gas of the engine 6. For example, the SCR 12b is a selective reduction catalyst that selectively reduces nitrogen oxides in the exhaust gas by using a reducing agent, thereby removing the nitrogen oxides.

[0078] Immediately after the engine 6 is started, the temperature of the catalyst in the post-treatment device 12 is lower than the catalyst activation temperature. Therefore, in order to improve the removal efficiency of nitrogen oxides, the preheating device 10 uses the heater 11 to heat the catalyst in the post-treatment device 12.

[0079] The circulation channel p7 is a channel that returns the air that has passed through the post-processing device 12 to the upstream side of the heater 11. The circulation channel p7 is equivalent to the first circulation channel in the present invention. Specifically, the circulation channel p7 has a first branch channel p7-1, a second branch channel p7-2, and a channel p7-3. The first branch channel p7-1 is a channel that branches from the exhaust channel p6 at a portion located upstream of the heat exchanger 13. The second branch channel p7-2 is a channel that branches from the exhaust channel p6 at a portion located downstream of the heat exchanger 13. Channel p7-3 is a channel that returns the air from the first branch channel p7-1 and the air from the second branch channel p7-2 to the exhaust channel p6. In addition, as described in detail later, the second branch channel p7-2 acts as a bypass channel, and the heated air is returned to the upstream side of the heater 11 in the bypass channel instead of being supplied to the heat exchanger 13.

[0080] The circulation passage p7 thus constructed is a passage that returns the air that has passed through the after-treatment device 12 to a position on the exhaust passage p6 , and is located downstream of the turbocharger 2 and upstream of the heater 11 .

[0081] A first valve Vl is provided at a portion where the first branch passage p7-1 branches from the exhaust passage p6. The first valve Vl is an electromagnetic valve, for example. The operation of the first valve Vl is controlled by the control device 15. The first valve Vl switches between a state where air that passes through the first valve Vl flows only through the first branch passage p7-1 (a state where air does not flow through the exhaust passage p6 downstream of the valve Vl but air flows through the first branch passage p7-1) and a state where air that passes through the first valve Vl flows only through the exhaust passage p6 (a state where air does not flow through the first branch passage p7-1 but air flows through the exhaust passage p6 downstream of the valve Vl).

[0082] A second valve V2 is provided at a portion where the second branch passage p7-2 branches from the exhaust passage p6. The second valve V2 is an electromagnetic valve, for example. The operation of the second valve V2 is controlled by the control device 15. The second valve V2 switches between a state where air that passes through the second valve V2 flows only through the second branch passage p7-2 (a state where air does not flow through the exhaust passage p6 downstream of the valve V2 but air flows through the second branch passage p7-2) and a state where air that passes through the second valve V2 flows only through the exhaust passage p6 (a state where air does not flow through the second branch passage p7-2 but air flows through the exhaust passage p6 downstream of the valve V2).

[0083] A heat exchanger 13 is provided on the exhaust passage p6, through which the air warmed by the heater 11 passes. The heat exchanger 13 has a function of warming the coolant in the coolant flow path L. Specifically, the heat exchanger 13 performs heat exchange between the warmed air that passes through the heat exchanger 13 and the coolant that flows through the coolant flow path L, thereby warming the coolant in the coolant flow path L.

[0084] The coolant flow path L is a flow path in which engine coolant flows, which is originally a structural portion for cooling the engine 6. In the present embodiment, the engine 6 can be warmed, and preheating the engine 6 can be performed by warming the coolant in the coolant flow path L and supplying it to the engine 6.

[0085] Although not shown in the drawings, a water pump for moving the coolant in the coolant flow path L can be provided on the coolant flow path L. The operation of the water pump is controlled by the control device 15, for example.

[0086] An air pump 14 is provided on the circulation passage p7, which circulates the air warmed by the heater 11. The air pump 14 is a blower in the present application, which supplies the warmed air to the aftertreatment device 12. Specifically, the air pump 14 is provided on the passage p7-3. The operation of the air pump 14 is controlled by the control device 15.

[0087] The control device 15 has a CPU (Central Processing Unit) and a storage section. The control device 15 is, for example, an ECU (Engine Control Unit). The ECU can be an engine ECU that controls the operation of the internal combustion engine 100 or can be an ECU provided separately from the engine ECU.

[0088] The control device 15 acquires an output value of a temperature sensor Tl that measures the temperature of the catalyst in the aftertreatment device 12. The temperature sensor Tl measures the temperature of at least one of the catalyst of the DOC 12a or the catalyst of the SCR 12b.

[0089] Further, the control device 15 acquires an output value of a temperature sensor T2 that measures the temperature of the engine 6. As an example, the temperature of the engine 6 is used to determine whether the engine 6 has been sufficiently warmed up.

[0090] The control device 15 controls the operation of the heater 11, the air pump 14, the first valve Vl, and the second valve V2. Specifically, the control device 15 controls the start and stop of the operation of the heater 11 and the output power of the heater 11. In addition, the control device 15 controls the start and stop of the operation of the air pump 14 and the output power of the air pump 14.

[0091] The storage section of the control device 15 stores threshold data used for various determinations of the control device 15. For example, the storage section stores the temperature of the catalyst of the aftertreatment device 12 used for determining that the catalyst needs to be warmed up, the target temperature of the catalyst set to be equal to or higher than the activation temperature of the catalyst, and the temperature of the engine 6 used for determining that the engine 6 has been sufficiently warmed up. As an example, the target temperature of the catalyst is equal to or higher than 160°C.

[0092] (Warming-up operation in engine stop state)

[0093] The operation of the warming-up device 10 thus configured to warm up the engine 6 and the catalyst in the aftertreatment device 12 in the stop state of the engine 6 will be described below. Figure 2 is a flowchart of the warming-up operation of the warming-up device 10 in the engine stop state.

[0094] First, in step S1, the control device 15 determines whether the engine 6 is stopped. The control device 15 determines whether the engine 6 is stopped based on specific information indicating that the engine 6 is stopped. For example, in the case where the vehicle is in the motor drive mode, the control device 15 determines that the engine 6 is stopped.

[0095] In the case where the engine 6 is stopped and the temperature of the catalyst in the aftertreatment device 12 is low, it is necessary to warm up the catalyst so that the temperature of the catalyst is equal to or higher than the activation temperature. In view of this, in the case where the engine 6 is stopped (Yes in step S1), in step S2, the control device 15 determines whether the temperature of the catalyst in the aftertreatment device 12 is equal to or lower than a predetermined threshold. Specifically, the control device 15 determines whether the temperature of the catalyst is equal to or lower than the predetermined threshold based on the output value from the temperature sensor T1 and the threshold stored in the storage section. Note that in the case where the determination result in step S1 is No, step S1 is repeated.

[0096] In the case where the temperature of the catalyst is equal to or lower than the predetermined threshold (Yes in step S2), in step S3, the control device 15 switches the flow path as a step before starting the preheating operation. The preheating device 10 according to the present embodiment supplies the air heated by the heater 11 to the aftertreatment device 12 and the heat exchanger 13. In view of this, in step S3, the control device 15 operates the first valve V1 and the second valve V2, switches the first valve V1 to a state in which the air flows only through the exhaust passage p6, and switches the second valve V2 to a state in which the air flows only through the second branch passage p7-2. In this state, the air that passes through the aftertreatment device 12 does not flow through the first branch passage p7-1 but flows through the heat exchanger 13 and is sent back to the upstream side of the heater 11 through the second branch passage p7-2 and the passage p7-3. Note that in the case where the determination result in step S2 is No, step S2 is repeated.

[0097] Next, in step S4, the control device 15 operates the heater 11 and the air pump 14 (blower). Thereby, the air heated by the heater 11 is supplied to the aftertreatment device 12 by the air pump 14. As a result of the heated air passing through the aftertreatment device 12, the catalyst in the aftertreatment device 12 is heated. Note that the start of the operation of the blower can be before the completion of the switching of the passage state in step S3.

[0098] The heated air that passes through the aftertreatment device 12 is supplied to the heat exchanger 13 through the exhaust passage p6. In the heat exchanger 13, the coolant in the coolant flow path L is warmed up as a result of heat exchange between the heated air and the coolant. When the warmed-up coolant is supplied to the engine 6, the engine 6 is preheated.

[0099] As an example, the heated air that passes through the heat exchanger 13 is not discharged to the atmosphere but is sent back to the upstream side of the heater 11 through the second branch passage p7-2 and the passage p7-3. According to the configuration in which the heated air circulates through the exhaust passage p6 and the circulation passage p7 in this way, the catalyst and the coolant can be effectively warmed up.

[0100] After the engine 6 is sufficiently warmed up, it is not necessary to supply the heated air to the heat exchanger 13. In view of this, in step S5, the control device 15 determines whether the temperature of the engine has exceeded a predetermined temperature. Specifically, the control device 15 determines whether the temperature of the engine has exceeded a predetermined temperature based on the output value from the temperature sensor T2 and the temperature stored in the storage portion as a threshold value.

[0101] When the temperature of the engine 6 has exceeded the predetermined threshold value in the state in which the heated air is supplied to the post-processing device 12 and the heat exchanger 13 (Yes in step S5), in step S6, the control device 15 switches the flow path of the valve. Specifically, the control device 15 causes the first valve Vl to operate, switching to a state in which the heated air flows only through the first branch passage p7-1 and circulates in the circulation passage p7. That is, in this state, the heated air is not supplied to the heat exchanger 13, but circulates in the circulation passage p7 through the first branch passage p7-1 and the passage p7-3. By not supplying air to the heat exchanger 13 in the case where the engine 6 is sufficiently warmed up in this way, it is possible to warm up the catalyst by effectively using the energy of the heated air. In the case where the determination result in step S5 is No, step S5 is repeated.

[0102] Next, in step S7, the control device 15 determines whether the temperature of the catalyst in the post-processing device 12 has exceeded a target temperature. Specifically, the control device 15 determines whether the temperature of the catalyst indicated by the output value of the temperature sensor Tl has exceeded the target temperature of the catalyst stored in the storage portion.

[0103] In the case where the temperature of the catalyst has exceeded the target temperature (Yes in step S7), in step S8, the control device 15 stops the operation of the heater 11 and the air pump 14. In the case where the determination result in step S7 is No, step S7 is repeated.

[0104] By the above series of steps, the preheating device 10 warms up the catalyst in the post-processing device 12. In addition, the preheating device 10 performs the preheating of the engine 6 by warming up the coolant in the coolant flow path L.

[0105] (Action and advantages)

[0106] As described above, according to the preheating device 10 according to the present embodiment, in the case where the catalyst in the post-processing device 12 is warmed up by the heater 11 in the stopped state of the engine 6, the engine coolant can also be warmed up by the air heated by the heater 11. Therefore, it is possible to perform the preheating of the engine 6 by effectively using the energy.

[0107] Since the heater 11, which is a heat source for warming the catalyst in the post-processing device 12, is used as a heat source for warming the coolant, it is not necessary to provide a heat source separate from the heater 11, and the configuration of the preheating device 10 does not become complicated.

[0108] In the present embodiment, specifically, when the engine is sufficiently preheated after the preheating of the catalyst in the post-processing device 12 and the engine coolant is started (see step S5), the flow path is changed by using the first valve Vl, and the heated air is circulated through the first branch passage p7-1, the passage p7-3, and the exhaust passage p6. Since the heated air is not supplied to the heat exchanger 13 in this state, the energy of the heated air is not used for warming the coolant, but the catalyst in the post-processing device 12 can be efficiently preheated.

[0109] Since two valves, i.e., the first valve Vl and the second valve V2, are provided in the present embodiment, as shown in FIG. 2, the operation of these valves under the control of the control device 15 can be switched between a state in which the heated air is circulated through the second branch passage p7-2, the passage p7-3, and the exhaust passage p6, and a state in which the heated air is circulated through the first branch passage p7-1, the passage p7-3, and the exhaust passage p6. Figure 1

[0110] Also in the present embodiment, the air blower for circulating the heated air can be formed in a relatively simple configuration including the circulation passage p7 and the air pump 14 provided on the circulation passage p7.

[0111] Although the above description refers to the specific configuration of the internal combustion engine 100, the present application is not necessarily limited to the above specific configuration. For example, the first valve Vl and / or the second valve V2 can be omitted. The preheating device 10 can perform the operation of warming the catalyst in the post-processing device 12 and the engine coolant while the air heated by the heater 11 is released to the atmosphere through the exhaust passage p6. Figure 1

[0112] Further, the coolant flow path L can be provided with a heat exchanger for exchanging heat between the air inside the vehicle and the coolant. By providing such a heat exchanger, it is also possible to effectively warm the inside of the vehicle using the air for warming the catalyst while the engine 6 is stopped.

[0113] <Second Embodiment>

[0114] Figure 3 is a view showing the configuration of an internal combustion engine in another embodiment of the present application. The configuration of the preheating device 10A is different from that of the first embodiment, and is the same as that of the first embodiment in other respects.

[0115] ​​The preheating device 10A includes an exhaust passage p6, a heater 11, a post-treatment device 12, a circulation passage p8, a second valve V2, an LP-EGR cooler 16, a coolant flow path L, and a control device 15. Compared to the configuration of the first embodiment, the heat exchanger 13, the air pump 14, the first valve V1, and the like are omitted from the preheating device 10A. Since the configuration is otherwise similar to that of the first embodiment, descriptions common to the first and second embodiments will be omitted.

[0116] The circulation passage p8 is a passage through which the air passing through the post-processing device 12 is sent back to the intake passage p1 of the turbocharger 2. The circulation passage p8 is equivalent to the second circulation passage in the present invention.

[0117] The LP-EGR (Low Pressure EGR) cooler 16 is provided on the circulation passage p8. The LP-EGR cooler 16 is a device for returning the exhaust gas to the passage between the air cleaner 1 and the turbocharger 2. Figure 2 In the configuration, the LP-EGR cooler 16 also functions as a heat exchanger. Specifically, the LP-EGR cooler 16 warms the coolant by exchanging heat between the air heated by the heater 11 and the engine coolant in the coolant flow path L, thereby preheating the engine 6.

[0118] As in the first embodiment, the control device 15 operates the heater 11 while the engine 6 is stopped, heating the air to warm the catalyst in the aftertreatment device 12. In this embodiment, the control device 15 also controls the operation of the electric supercharger 4. Specifically, the control device 15 operates the electric supercharger 4 to supply compressed air upstream of the heater 11 in the exhaust passage p6 through the EGR pipe section 7.

[0119] The compressed air supplied to the upstream side of the heater 11 in this manner is heated by the heater 11, and like the first embodiment, the heated air is supplied to the post-processing device 12. Thereby, the catalyst in the post-processing device 12 is heated.

[0120] The heated air passing through the post-treatment device 12 flows into the circulation passage p8 through the exhaust passage p6 and the second valve V2. By passing the heated air through the LP-EGR cooler 16, heat exchange is performed between the heated air and the coolant in the coolant flow path L, thereby warming the coolant in the coolant flow path L.

[0121] Since the loop channel p8 is Figure 3 The air is connected to the intake passage p1 in a configuration similar to that described above, and the air passing through the LP-EGR cooler 16 is sent back to the upstream side of the turbocharger 2. Thereafter, the air passes through the turbocharger 2, the first charge air cooler 3, and the electric supercharger 4, and is then sent back again to the upstream side of the heater 11 along a flow path similar to that described above.

[0122] As described above, in the present application, the air blower that sends out the air heated by the heater 11 is not necessarily limited to the air pump 14, and can be, for example, the electric supercharger 4 located upstream of the engine 6. According to the configuration as shown in FIG. 1, the air pump 14 is not required to be provided, and the electric supercharger 4 is provided. Figure 3 According to the configuration as shown in FIG. 1, the air pump 14 is not required to be provided, and the electric supercharger 4 is provided.

[0123] Note that, Figure 3 A configuration example in which the electric compressor having the motor and the compressor is provided instead of the turbo is shown. However, the electrically assisted turbocharger can be used in the present application. The electrically assisted turbocharger is a turbocharger in which the motor is provided between the compressor and the turbo, and is capable of compressing the air using the driving force of the motor.

[0124] <Modification Example>

[0125] In the above-described embodiment, the engine coolant is warmed up to warm up the engine 6 by using the heat for warming up the catalyst in the post-processing device 12. In one form of the present application, the warming-up device can warm up the interior of the vehicle by using the warmed-up coolant.

[0126] Although the present application has been described above using the embodiments, the technical scope of the present application is not limited to the scope of the above-described embodiments, but various changes can be made within the scope of the gist. For example, the specific embodiments regarding the distribution / integration of the devices are not limited to the above-described embodiments, and all or a part of them can be provided in any unit in a functionally or physically distributed / integrated manner. In addition, the embodiments of the present application also include new embodiments generated by combining any of the plurality of embodiments. The advantages of the new embodiments generated by the combination combine the advantages of the original embodiments.

Claims

1. An internal combustion engine warm-up device, comprising: an exhaust treatment device having a catalyst and removing nitrogen oxides in exhaust gas passing through an exhaust passage from an engine; a heater provided on the exhaust passage upstream of the exhaust treatment device; a circulation passage in which air passing through the exhaust treatment device is sent back to an upstream side of the heater; a blower that sends air heated by the heater to the exhaust treatment device; a coolant flow path in which coolant of the engine flows; a heat exchanger that warms the coolant in the coolant flow path by exchanging heat between the heated air passing through the exhaust treatment device and the coolant; a control device that controls operation of the heater and the blower, wherein in a state in which the engine is stopped, the control device operates the heater and the blower and supplies air heated by the heater to the exhaust treatment device and the heat exchanger. in a case where a temperature of the catalyst in the exhaust treatment device is equal to or lower than a predetermined threshold, the control device operates the heater and the blower.

2. The preheating device for internal combustion engine according to claim 1, wherein 3. The internal combustion engine warm-up device according to claim 1 or 2, wherein the heat exchanger is provided on the exhaust passage, the circulation passage includes a first branch passage that branches from the exhaust passage at a portion upstream of the heat exchanger, the internal combustion engine warm-up device further includes a first valve provided at a portion where the first branch passage branches from the exhaust passage and switches between a state in which heated air flows through the first branch passage and a state in which the heated air flows through the exhaust passage, and in a state in which the heated air is supplied to the exhaust treatment device and the heat exchanger, when a temperature of the engine exceeds a predetermined threshold, the control device controls the first valve and causes the heated air to flow through the first branch passage and circulate in the circulation passage. in a state in which the heated air is supplied to the exhaust treatment device and the heat exchanger, when the temperature of the engine exceeds the predetermined threshold, the control device controls the first valve and causes the heated air to flow through only the first branch passage and circulate in the circulation passage.

4. The preheating device for internal combustion engine according to claim 3, wherein 5. The internal combustion engine warm-up device according to claim 3, wherein the heat exchanger is provided on the exhaust passage, the circulation passage includes a second branch passage that branches from the exhaust passage at a portion downstream of the heat exchanger, the internal combustion engine warm-up device further includes a second valve provided at a portion where the second branch passage branches from the exhaust passage and switches between a state in which the heated air flows through the second branch passage and a state in which the heated air flows through the exhaust passage, and in a state in which the heated air is supplied to the exhaust treatment device and the heat exchanger, when a temperature of the engine exceeds a predetermined threshold, the control device controls the second valve and causes the heated air to flow through the second branch passage and circulate in the circulation passage. The control device controls the first valve and the second valve to switch the first valve to a state in which the heated air flows through the exhaust passage, to switch the second valve to a state in which the heated air flows through the second branch passage before causing the heater and the blower to operate, and then to cause the heater and the blower to operate to supply the heated air to the aftertreatment device and the heat exchanger.

6. The internal combustion engine warming-up device according to claim 1 or 2, wherein the circulation passage is a first circulation passage and is located downstream of a turbocharger and upstream of the heater, the air that has passed through the aftertreatment device is sent back to a position on the exhaust passage in the first circulation passage, and a gas pump is provided as the blower on the first circulation passage.

7. The internal combustion engine warming-up device according to claim 1 or 2, wherein the circulation passage is a second circulation passage, the air that has passed through the aftertreatment device is sent back to an intake passage of a turbocharger in the second circulation passage, and the heat exchanger is a low-pressure EGR cooler provided on the second circulation passage.

8. The internal combustion engine warming-up device according to claim 1 or 2, wherein the circulation passage is a third circulation passage, the air that has passed through the aftertreatment device is sent back to an intake passage of a turbocharger in the third circulation passage, and the heat exchanger is a high-pressure EGR cooler provided on the third circulation passage.

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