JP2018193957A - Engine warming-up system - Google Patents

Abstract

To more efficiently warm up an engine with an electric supercharger.SOLUTION: An engine warming-up system 100 includes: an intake flow passage 18; an electric supercharger 22; an exhaust flow passage 20; an EGR flow passage 32; a fresh air control valve 25 for opening/closing the intake flow passage; a throttle valve 24 for opening/closing the intake flow passage; an EGR valve 34 for opening/closing the EGR flow passage; an intake valve 12 and an exhaust valve 13 of an engine; an intake/exhaust valve control section 114 for performing opening control of the intake valve and the exhaust valve during stop of the engine; a first valve control section 116 performing control for closing the fresh air control valve and opening the EGR valve when a predetermined engine warming-up execution condition is satisfied; an electric supercharger control section 118 for driving the electric supercharger when the engine warming-up execution condition is satisfied; and a second valve control section 122 for controlling an opening of the throttle valve to drive the electric supercharger in a predetermined driving region when the engine warming-up execution condition is satisfied.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an engine warm-up system for warming up an engine.

  An engine having an electric supercharger that compresses intake air is known.

  As a technique using this electric supercharger, for example, in the technique described in Patent Document 1, the electric supercharger is driven and the gas is circulated through the EGR path while the engine is stopped. The catalyst is warmed up.

JP 2008-255940 A

  When warming up using an electric supercharger like the technique described in Patent Document 1, it is desirable to use an electric supercharger as a heat source more efficiently.

  Then, an object of this invention is to provide the engine warming-up system which can warm up more efficiently in the engine provided with the electric supercharger.

  In order to solve the above-described problems, an engine warm-up system according to the present invention is connected to an engine, an intake passage through which intake air circulates, and an electric engine that is provided in the middle of the intake passage and compresses intake air by driving a motor. A turbocharger connected to the engine and exhaust gas exhausted; and an EGR channel that recirculates the exhaust gas exhausted to the exhaust flow channel upstream of the electric supercharger in the intake flow channel; A fresh air control valve provided on the upstream side of the merging position of the EGR flow path in the intake flow path, and provided downstream of the electric supercharger in the intake flow path. A throttle valve that opens and closes, an EGR valve that opens and closes the EGR flow path provided in the EGR flow path, an intake valve that opens and closes between the intake port and the combustion chamber of the engine, and opens and closes between the exhaust port and the combustion chamber of the engine Exhaust And an intake / exhaust valve control unit that controls the intake valve and the exhaust valve to be opened while the engine is stopped, and a control that closes the fresh air control valve and opens the EGR valve when a predetermined engine warm-up execution condition is satisfied. A first valve control unit to perform, an electric supercharger control unit for driving the electric supercharger when the engine warm-up execution condition is satisfied, and an electric supercharger in a predetermined drive region when the engine warm-up execution condition is satisfied And a second valve control unit that adjusts the opening of the throttle valve so as to be driven at the same time.

  The drive region may be a region where the pressure ratio is higher and the flow rate is lower than when the electric supercharger is normally driven.

  In addition, a pressure sensor that measures the pressure downstream of the electric supercharger in the intake passage is provided, and the second valve control unit adjusts the opening of the throttle valve based on the pressure measured by the pressure sensor. May be.

  ADVANTAGE OF THE INVENTION According to this invention, in the engine provided with the electric supercharger, it can warm up more efficiently.

It is the schematic explaining the engine warming-up system in this embodiment. It is explanatory drawing which shows the flow of the air during warming-up. It is a figure which shows the map of the efficiency at the time of an electric supercharger driving. It is a flowchart explaining the engine warm-up process at the time of an engine stop. It is a flowchart explaining the engine warm-up process at the time of engine starting. It is a figure which shows the modification in this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  FIG. 1 is a schematic diagram illustrating an engine warm-up system 100 in the present embodiment. First, the schematic configuration of the engine 1 will be described, and then the configuration of the engine warm-up system 100 will be described. In FIG. 1, the signal flow is indicated by broken arrows.

  As shown in FIG. 1, the engine 1 is a horizontally opposed four-cylinder engine in which cylinder bores 3a formed in two cylinder blocks 3 are opposed to each other with a crankshaft 2 interposed therebetween.

  A crankcase 4 is formed integrally with the cylinder block 3, and a cylinder head 5 is fixed to the opposite side of the crankcase 4. The crankshaft 2 is rotatably supported in a crank chamber 6 formed by the crankcase 4.

  A piston 8 connected to the crankshaft 2 via a connecting rod 7 is slidably accommodated in the cylinder bore 3a. In the engine 1, a space surrounded by the cylinder bore 3 a, the cylinder head 5, and the crown surface of the piston 8 is formed as the combustion chamber 9.

  An intake port 10 and an exhaust port 11 are formed in the cylinder head 5 so as to communicate with the combustion chamber 9. Between the intake port 10 and the combustion chamber 9, the tip of the intake valve 12 is located, and between the exhaust port 11 and the combustion chamber 9, the tip of the exhaust valve 13 is located.

  In the engine 1, an intake valve cam 15 and an exhaust valve cam 16 are provided in a cam chamber surrounded by the cylinder head 5 and the head cover 14. The intake valve cam 15 is in contact with the other end of the intake valve 12 and rotates to move the intake valve 12 in the axial direction. As a result, the intake valve 12 opens and closes between the intake port 10 and the combustion chamber 9. The exhaust valve cam 16 is in contact with the other end of the exhaust valve 13 and rotates to move the exhaust valve 13 in the axial direction. Thereby, the exhaust valve 13 opens and closes between the exhaust port 11 and the combustion chamber 9.

  An intake passage 18 including an intake manifold 17 is communicated with the upstream side of the intake port 10. Further, an exhaust passage 20 including an exhaust manifold 19 is communicated with the downstream side of the exhaust port 11. Exhaust gas discharged from the combustion chamber 9 is collected by the exhaust manifold 19 via the exhaust port 11 and guided to the exhaust passage 20.

  An air cleaner 21, a compressor impeller 22c, an intercooler 23, a throttle valve 24, and an intake manifold 17 are provided in the intake passage 18 in order from the upstream side. Here, in the intake flow path 18, the upstream side of the compressor impeller 22c is referred to as an upstream intake flow path 18a, and the downstream side of the compressor impeller 22c is referred to as a downstream intake flow path 18b.

  A fresh air control valve 25 is provided in the upstream intake passage 18a. The fresh air control valve 25 adjusts the flow rate of air (intake air) sucked from outside through the air cleaner 21 by adjusting the opening degree.

  The electric supercharger 22 includes a motor 22a, a shaft 22b, and a compressor impeller 22c. The motor 22a is driven by supplying electric power. The shaft 22b is connected to the motor 22a and rotates by driving the motor 22a. The compressor impeller 22c is connected to the shaft 22b and rotates integrally with the shaft 22b.

  The compressor impeller 22c is rotated by driving the motor 22a, thereby compressing air (intake air) from which impurities such as dust and dirt have been removed by the air cleaner 21 and supplying the compressed air to the downstream intake passage 18b.

  The intercooler 23 cools the intake air compressed by the compressor impeller 22c and heated. The cooled air is guided to the combustion chamber 9 through the throttle valve 24, the intake manifold 17 and the intake port 10.

  The throttle valve 24 varies the flow rate of the intake air supplied to the combustion chamber 9 by adjusting the opening degree by an actuator (not shown). Detailed control of the throttle valve 24 will be described later.

  The intake passage 18 is provided with an air bypass passage 26 that bypasses the compressor impeller 22c. The air bypass passage 26 is connected between the fresh air control valve 25 and the compressor impeller 22c in the upstream side intake passage 18a. The air bypass passage 26 is connected between the intercooler 23 and the throttle valve 24 in the downstream intake passage 18b. An air bypass valve 27 is interposed in the air bypass channel 26. The air bypass valve 27 is opened when the driver releases the accelerator and the throttle valve 24 is closed, and prevents the pressure in the downstream intake passage 18b from becoming excessive.

  In addition, a first bypass passage 28 that bypasses the intercooler 23 is provided in the downstream side intake passage 18b. A first flow path switching valve 29 is provided at a location connecting the upstream side of the first bypass flow path 28 and the downstream intake flow path 18b. The first flow path switching valve 29 switches the flow path so that the intake air flows through either the intercooler 23 or the first bypass flow path 28.

  In the engine 1, an air-fuel mixture of intake air guided to the combustion chamber 9 and fuel injected from an injector (not shown) is ignited at a predetermined timing by an ignition plug (not shown) provided in the cylinder head 5 and burned. Is done. By such combustion, the piston 8 reciprocates in the cylinder bore 3 a, and the reciprocating motion is converted into the rotational motion of the crankshaft 2 through the connecting rod 7.

  Further, the exhaust gas generated by the combustion is discharged outside the vehicle through the exhaust port 11 and the exhaust passage 20. The exhaust passage 20 is provided with an upstream catalyst 30 and a downstream catalyst 31. The upstream catalyst 30 and the downstream catalyst 31 purify the exhaust gas flowing through the exhaust passage 20. The upstream catalyst 30 and the downstream catalyst 31 may be a filter device with a catalytic function.

  Further, an EGR (Exhaust Gas Recirculation) that connects between the upstream catalyst 30 and the downstream catalyst 31 in the exhaust passage 20 and between the fresh air control valve 25 and the compressor impeller 22c in the upstream intake passage 18a. ) A flow path 32 is provided. The EGR flow path 32 recirculates a part of the exhaust gas flowing through the exhaust flow path 20 to the upstream side intake flow path 18a (hereinafter, the recirculated exhaust gas is referred to as “EGR gas”).

  The EGR flow path 32 is provided with an EGR cooler 33 and an EGR valve 34 in order from the upstream side. The EGR cooler 33 cools the EGR gas. The EGR valve 34 adjusts the flow rate of the EGR gas flowing through the EGR flow path 32 by adjusting the opening degree.

  The EGR flow path 32 is provided with a second bypass flow path 35 that bypasses the EGR cooler 33. A second flow path switching valve 36 is provided at a location connecting the upstream side of the second bypass flow path 35 and the EGR flow path 32. The second flow path switching valve 36 switches the flow path so that EGR gas (air) flows through either the EGR cooler 33 or the second bypass flow path 35.

  The engine warm-up system 100 is provided with a control device 110. A first pressure sensor (pressure sensor) 50, a second pressure sensor 52, a first temperature sensor 54, a second temperature sensor 56, a third temperature sensor 58, and an engine start switch sensor 60 are connected to the control device 110.

  The first pressure sensor 50 is provided between the intercooler 23 and the throttle valve 24 in the downstream intake passage 18b, and measures the pressure in the downstream intake passage 18b. The first pressure sensor 50 transmits a detection signal corresponding to the pressure (pressure P1) in the downstream side intake flow path 18b to the control device 110.

  The second pressure sensor 52 is provided on the downstream side of the connection portion of the EGR flow path 32 in the upstream intake flow path 18a, and measures the pressure in the upstream intake flow path 18a. In addition, the second pressure sensor 52 transmits a detection signal corresponding to the pressure (pressure P2) in the upstream side intake flow path 18a to the control device 110.

  The first temperature sensor 54 is provided in the cylinder block 3 and measures the temperature of the cooling water flowing through the engine 1. The first temperature sensor 54 transmits a detection signal corresponding to the temperature (temperature T1) in the engine 1 to the control device 110.

  The second temperature sensor 56 is provided on the upstream side of the fresh air control valve 25 in the upstream intake passage 18a, and measures the temperature of the intake air (intake). The second temperature sensor 56 transmits a detection signal corresponding to the temperature (temperature T2) of the intake air (outside air) to the control device 110.

  The third temperature sensor 58 is provided in the intake manifold 17 and measures the temperature of the air flowing through the intake manifold 17. The third temperature sensor 58 transmits a detection signal corresponding to the temperature (temperature T3) in the intake manifold 17 to the control device 110.

  When an engine start switch (not shown) is turned on, the engine start switch sensor 60 transmits an engine start switch on signal indicating that the engine start switch is turned on to the control device 110. Further, when the engine start switch is turned off, the engine start switch sensor 60 transmits an engine start switch off signal indicating that the engine start switch is turned off to the control device 110.

  The control device 110 is, for example, an ECU (Engine Control Unit), and includes a central processing unit (CPU), a ROM storing programs, a semiconductor integrated circuit including a RAM as a work area, and the like. Control. In addition to controlling the operation of the entire vehicle including the engine 1, the control device 110 controls the drive control unit 112, the intake / exhaust valve control unit 114, the first valve control unit 116, the electric supercharger control unit 118, the first flow. It also functions as a path switching valve control section 120, a second valve control section 122, and a second flow path switching valve control section 124. Hereinafter, a specific operation of the engine warm-up system 100 will be described.

  FIG. 2 is an explanatory diagram showing the air flow during warm-up. In FIG. 2, black arrows indicate the flow of air.

  When the drive control unit 112 receives the engine start switch off signal sent from the engine start switch sensor 60, the drive control unit 112 stops the engine 1.

  The intake / exhaust valve control unit 114 controls the intake valve 12 and the exhaust valve 13 to an open state (overlap state) when the engine 1 is stopped. Thereby, in the engine 1, the state which the intake port 10 and the combustion chamber 9 were connected is maintained. Further, in the engine 1, the state where the exhaust port 11 and the combustion chamber 9 are communicated with each other is maintained.

  Thereafter, when the engine start switch is turned on (receives an engine start switch on signal), the control device 110 starts the engine 1, but when the engine 1 is at a low temperature, the viscosity of the engine oil is high. As a result, the startability of the engine 1 is reduced. Therefore, in the engine warm-up system 100, when the engine warm-up execution condition is satisfied when the engine start switch is turned on, the engine warm-up is executed. The engine warm-up execution condition is that the temperature (temperature T1) in the engine 1 is lower than a predetermined temperature that is set at a low temperature. The warm-up by the engine warm-up system 100 is performed for the first purpose of stabilizing the combustion at the start-up even when the outside air temperature is low by warming up the combustion chamber 9 of the engine 1.

  The first valve control unit 116 closes the fresh air control valve 25 when it is determined that the engine warm-up execution condition is satisfied. At the same time, the first valve control unit 116 opens the EGR valve 34.

  Further, the first flow path switching valve control unit 120 controls the first flow path switching valve 29 so that air flows through the first bypass flow path 28.

  Further, the second flow path switching valve control unit 124 controls the second flow path switching valve 36 so that air flows through the second bypass flow path 35.

  As described above, the intake valve 12 and the exhaust valve 13 are maintained in the open state, and the open / closed state of each valve is controlled, so that the interior of the engine 1 (combustion chamber 9) is shown in FIG. A flow path in which air circulates is formed.

  Then, the electric supercharger control unit 118 drives the electric supercharger 22 with a predetermined constant power. At this time, since the fresh air control valve 25 is closed, outside air is not taken into the intake flow path 18 even when the electric supercharger 22 is driven. Further, since the EGR valve 34 is opened, the compressor impeller 22 c sucks air from the EGR flow path 32 when the electric supercharger 22 is driven. Further, since the electric supercharger 22 is driven, the inside of the EGR flow path 32 becomes a negative pressure. Since the inside of the EGR flow path 32 has a negative pressure, air is not discharged downstream of the exhaust flow path 20 (downstream of the downstream side catalyst 31). Therefore, once warmed air can be used for warming up again without wasting it.

  The second valve control unit 122 controls the throttle valve 24 so that the electric supercharger 22 is driven in a predetermined region. Detailed control of the throttle valve 24 will be described later.

  As a result, the air compressed and warmed by the electric supercharger 22 bypasses the intercooler 23 and is guided into the engine 1 in the process of flowing through the downstream intake passage 18b. The engine 1 is warmed by the heat of the introduced air. The air that has passed through the engine 1 is recirculated to the upstream intake passage 18a, bypassing the EGR cooler 33, in the course of flowing through the exhaust passage 20 and the EGR passage 32.

  In this way, by bypassing the intercooler 23 and the EGR cooler 33, the engine 1 can be warmed earlier (efficiently) than when passing through the intercooler 23 and the EGR cooler 33.

  Then, the control device 110 warms up the engine 1 until the temperature in the intake manifold 17 (temperature T3) becomes equal to or higher than the threshold T based on the temperature of the outside air (temperature T2). The threshold value T is a value higher than the temperature of the outside air (temperature T2), and is a value that differs depending on the temperature of the outside air (temperature T2), and the threshold value T when the temperature of the outside air (temperature T2) is low. Is relatively lower than that when the outside air temperature (temperature T2) is high.

  Then, the drive control unit 112 determines the end of engine warm-up based on the temperature (temperature T3) in the intake manifold 17 and the threshold T, and drives (starts) the engine 1.

  By the way, when the electric supercharger 22 rotates the compressor impeller 22c, useless energy (heat generation) is generated. Therefore, during normal engine driving, the electric supercharger 22 is controlled (adiabatic compression is performed) so as to minimize heat generation (to improve efficiency) when the intake air is compressed.

  On the other hand, when warming up using the electric supercharger 22, if the electric supercharger 22 is driven in the same way as during normal engine driving, the heat generation of the electric supercharger 22 is minimized and the warming-up efficiency decreases. To do. Therefore, in the engine warm-up system 100 according to the present embodiment, the electric supercharger 22 is controlled by driving different from normal, and warms up the engine 1.

  FIG. 3 is a diagram showing a map of efficiency when the electric supercharger 22 is driven. In FIG. 3, the vertical axis represents the pressure ratio, and the horizontal axis represents the flow rate. The pressure ratio is a ratio between the pressure of air flowing through the electric supercharger 22 and the pressure of air compressed by the electric supercharger 22. The flow rate is a mass flow rate of the air compressed by the electric supercharger 22. The control of the throttle valve 24 will be described with reference to FIG. In FIG. 3, the broken line indicates the efficiency (power efficiency) of the electric supercharger 22. In addition, each power efficiency line ad shows the same power efficiency. In FIG. 3, the alternate long and short dash line indicates the electric power input to the electric supercharger 22. In addition, each power line shown with a dashed-dotted line shows equal electric power.

  As shown in FIG. 3, the power efficiency of the electric supercharger 22 becomes higher toward the center in the figure. For example, in the inner region surrounded by the power efficiency line a, the electric supercharger 22 is driven with an efficiency of 85% or more. The electric supercharger 22 has an efficiency of 80% to 85% in the inner region surrounded by the power efficiency line b, and an efficiency of 75% to 80% in the inner region surrounded by the power efficiency line c. The inner region surrounded by the efficiency line d is driven with an efficiency of 70% to 75%.

  The inner area A surrounded by the power efficiency line a indicates the power efficiency when the electric supercharger 22 is normally driven. As described above, in the inner region surrounded by the power efficiency line a, the electric supercharger 22 is driven with an efficiency of 85% or more, for example. At that time, heat generated by driving the electric supercharger 22 is about 10%. Therefore, the electric supercharger 22 can efficiently compress air by being driven in the region A.

  On the other hand, the amount of heat generated by driving the electric supercharger 22 increases as the distance from the power efficiency line a increases in the order of the power efficiency line b, the power efficiency line c, and the power efficiency line d. As the amount of heat generation increases, the power efficiency of the electric supercharger 22 deteriorates, but the energy generated by the heat generation is transmitted to the air flowing through the intake passage 18 and the temperature of the air increases.

  Here, in FIG. 3, the area surrounded by the solid line indicated by low is less efficient (low) than the area surrounded by the solid line indicated by high (when the electric supercharger 22 is normally driven). Efficiency). In FIG. 3, the left region is referred to as region B, and the right region is referred to as region C. However, in the region B and the region C, the efficiency of the electric supercharger 22 is substantially equal.

  In the region B and the region C, the amount of heat generated from the electric supercharger 22 is substantially the same. However, when the electric power supplied to the electric supercharger 22 is the same, in the region B, air is compressed more and the flow rate is reduced compared to the region A. On the other hand, in region C, air is not compressed and the flow rate is increased compared to region A. Therefore, driving the electric supercharger 22 in the region B can increase the temperature of the air by an amount corresponding to the temperature increase due to the compression, compared to driving the electric supercharger 22 in the region C.

  Therefore, in the engine warm-up system 100 of the present embodiment, the opening degree of the throttle valve 24 is adjusted so that the electric supercharger 22 is driven in the region B, and the engine 1 is warmed up.

  Specifically, during the engine warm-up process, the second valve control unit 122 derives a pressure ratio based on the pressure P1 and the pressure P2 measured by the first pressure sensor 50 and the second pressure sensor 52. Next, the 2nd valve control part 122 controls the opening degree of the throttle valve 24 so that the electric supercharger 22 drives in the area | region B using the map of FIG. Here, for example, when the pressure ratio decreases, the opening degree of the throttle valve 24 is decreased so that the pressure ratio increases, and when the pressure ratio increases, the throttle valve 24 decreases so that the pressure ratio decreases. The electric supercharger 22 is driven in the region B by increasing the opening degree.

  Thus, the engine warm-up system 100 drives the electric supercharger 22 in the region B where the temperature of the air is highest, and can warm up the engine 1 early.

(Engine warm-up treatment)
Next, the flow of engine warm-up processing by the engine warm-up system 100 will be described. FIG. 4 is a flowchart for explaining engine warm-up processing when the engine 1 is stopped.

  First, the control device 110 determines whether or not the engine start switch is turned off based on a signal transmitted from the engine start switch sensor 60 (S10). If it is determined that the engine start switch has been turned off (YES in step S10), the intake / exhaust valve control unit 114 controls the intake valve 12 and the exhaust valve 13 to an open state (overlap state) (S12). Thereafter, the drive control unit 112 also stops the engine 1 (S14) and ends the engine warm-up process when the engine 1 is stopped.

  On the other hand, when controller 110 determines that the engine start switch is not turned off (NO in step S10), it repeats the process of step S10 until it is determined that the engine start switch is turned off.

  FIG. 5 is a flowchart for explaining engine warm-up processing when the engine 1 is started. The engine warm-up process when the engine 1 is started is a process executed when the engine start switch is turned on.

  When the engine start switch is turned on, the electric supercharger control unit 118 determines whether or not the engine warm-up execution condition is satisfied. Specifically, as described above, the temperature T1 is lower than the predetermined temperature. It is determined whether or not (S20). Note that the temperature T2 may be added to the determination as to whether the engine warm-up execution condition is satisfied. In this case, it is determined that the engine warm-up execution condition is satisfied when the temperature T1 and the temperature T2 are equal to or lower than the temperature (threshold value) set for each.

  If it is determined that the engine warm-up execution condition is satisfied (YES in step S20), the first valve control unit 116 closes the fresh air control valve 25 and opens the EGR valve 34 (S22). . Further, the first flow path switching valve control unit 120 controls the first flow path switching valve 29 so that air flows through the first bypass flow path 28. Further, the second flow path switching valve control unit 124 controls the second flow path switching valve 36 so that air flows through the second bypass flow path 35.

  Then, the electric supercharger control unit 118 drives the electric supercharger 22 with a predetermined power (S24). Further, the second valve control unit 122 controls the throttle valve 24 so that the electric supercharger 22 is driven in a predetermined region B (see FIG. 3) (S26).

  Then, the electric supercharger control unit 118 determines whether or not the engine warm-up termination condition is satisfied based on the temperature T3 (S28). Specifically, when a predetermined time has elapsed after the temperature T3 in the intake manifold 17 reaches the threshold value T, it is determined that the engine warm-up termination condition is satisfied. If it is determined that the engine warm-up end condition is satisfied (YES in step S28), the drive control unit 112 ends the engine warm-up and drives (starts) the engine 1 (S30). The engine warm-up process at the start of is finished.

  On the other hand, when it is determined that the engine warm-up termination condition is not satisfied (NO in step S28), control device 110 returns the process to S26. When the engine warm-up system 100 is warming up before starting the engine, it is difficult to accurately grasp the temperature of the combustion chamber 9 based on the temperature T1 indicating the temperature in the engine 1 (cooling water temperature). . Therefore, in the present embodiment, the temperature T3 in the intake manifold 17, in other words, the temperature of the air supplied to the combustion chamber 9 is used to determine the end of engine warm-up. In addition, the elapsed time after the temperature T3 reaches the threshold value T is confirmed in consideration of the heat capacity of the combustion chamber 9. Note that the end of the engine warm-up may be determined based on the temperature T3 and the flow rate history (the integrated value of the air flow rate after the engine warm-up has started).

  In addition, if it is determined that the engine warm-up execution condition is not satisfied (NO in S20), electric supercharger control unit 118 ends the engine warm-up process at the time of starting engine 1. The fact that the engine warm-up execution condition is not satisfied means that the engine 1 is not in the cold state. Therefore, since there is no need to warm the inside of the engine 1, the electric supercharger control unit 118 ends the engine warm-up process when the engine 1 is started.

  With this configuration, when the engine 1 is driven in a cold state, the engine warm-up system 100 first drives the electric supercharger 22 so that the heat insulation efficiency of the electric supercharger 22 is normally controlled (region A shown in FIG. 3). ) The opening of the throttle valve 24 is controlled so as to be in a different region (region B shown in FIG. 3). As a result, the air compressed (supercharged) by the electric supercharger 22 and warmed can be circulated in the engine 1. Therefore, the engine 1 can be warmed up quickly and efficiently by controlling the opening degree of the throttle valve 24.

  FIG. 6 is a diagram illustrating a modification example of the present embodiment. Note that a description of a configuration substantially the same as the engine warm-up system 100 described above will be omitted. As shown in FIG. 6, the engine 1 is provided with an engine warm-up system 200. Specifically, the engine warm-up system 200 is configured to newly include an exhaust control valve 202, a heater 204, and a control device 210.

  The exhaust control valve 202 is provided on the downstream side of the exhaust passage 20 where the EGR passage 32 is connected and on the upstream side of the downstream side catalyst 31.

  The heater 204 is provided upstream of the upstream catalyst 30 in the exhaust passage 20. The heater 204 warms the air (exhaust gas) flowing through the exhaust passage 20.

  The control device 210 newly functions as a third valve control unit 212 and a heater control unit 214 in addition to the functions of the control device 110 described above.

  The third valve control unit 212 controls the opening degree of the exhaust control valve 202. The third valve control unit 212 closes the exhaust control valve 202 after determining that the engine warm-up execution condition is satisfied. At this time, the first valve control unit 116 closes the fresh air control valve 25 and opens the EGR valve 34. For this reason, the flow path in the engine warm-up system 200 is sealed. Therefore, outside air (cold air) does not enter the engine 1 while the air circulates. Therefore, the engine 1 can be warmed up more effectively (more positively) and at an early stage.

  The heater control unit 214 heats the heater 204. The heater control unit 214 heats the heater 204 after determining that the engine warm-up execution condition is satisfied. The temperature of the air compressed and warmed by the electric supercharger 22 is lowered by passing through the engine 1. Therefore, the temperature of the air flowing through the exhaust passage 20 is lower than that of the air passing through the downstream intake passage 18b. Therefore, the heater 204 is provided in the exhaust flow path 20, and the temperature of the circulating air is raised by warming the circulating air. By raising the temperature of the refluxing air, when the air is compressed again by the electric supercharger 22, it is compressed to a higher temperature. Thus, by warming and circulating the recirculated air, the engine 1 can be warmed up more effectively (more positively) and at an early stage.

  Further, by providing the heater 204 on the upstream side of the upstream catalyst 30 in the exhaust passage 20, the upstream catalyst 30 can be warmed. By warming the upstream catalyst 30, the upstream catalyst 30 can be activated early.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  For example, although the case where the engine warm-up process is executed when the engine 1 is in the cold state has been described in the above embodiment, the engine warm-up process may be executed even when the engine 1 is not in the cold state.

  In the above embodiment, the case where the first bypass flow path 28 that bypasses the intercooler 23 is provided in the downstream side intake flow path 18b has been described. However, the first bypass channel 28 is not an essential configuration.

  In the above-described embodiment, the case where the second bypass flow path 35 that bypasses the EGR cooler 33 is provided in the EGR flow path 32 has been described. However, the second bypass channel 35 is not an essential configuration.

  In the above embodiment, the case where the engine warm-up systems 100 and 200 are provided with the first bypass passage 28 and the second bypass passage 35 has been described. However, both the first bypass channel 28 and the second bypass channel 35 may not be provided. At least one of the first bypass channel 28 and the second bypass channel 35 may be provided.

  Further, in the above embodiment, the case where the engine warm-up systems 100 and 200 are provided with the first pressure sensor 50 and the second pressure sensor 52 and the opening degree of the throttle valve 24 is controlled based on the pressure ratio has been described. However, the flow rate may be derived using a flow rate sensor instead of the pressure sensor, and the opening degree of the throttle valve 24 may be controlled.

  Further, in the above modification, the case where the engine warm-up system 200 is further provided with the exhaust control valve 202 and the heater 204 has been described. However, both the exhaust control valve 202 and the heater 204 may not be provided. At least one of the exhaust control valve 202 and the heater 204 may be provided.

  The present invention can be used for an engine warm-up system.

1 Engine 9 Combustion chamber 10 Intake port 11 Exhaust port 12 Intake valve 13 Exhaust valve 18 Intake passage 20 Exhaust passage 22 Electric supercharger 22a Motor 24 Throttle valve 25 Fresh air control valve 32 EGR passage 34 EGR valve 50 First Pressure sensor (pressure sensor)
100 Engine warm-up system 114 Intake / exhaust valve control unit 116 First valve control unit 118 Electric supercharger control unit 122 Second valve control unit

Claims (3)

An intake passage connected to the engine and through which intake air flows;
An electric supercharger that is provided in the middle of the intake flow path and compresses intake air by driving a motor;
An exhaust passage connected to the engine for exhaust gas exhaust;
An EGR passage that recirculates exhaust gas discharged to the exhaust passage upstream of the electric supercharger in the intake passage;
A fresh air control valve that is provided upstream of the merge position of the EGR flow path in the intake flow path, and opens and closes the intake flow path;
A throttle valve that is provided downstream of the electric supercharger in the intake passage, and opens and closes the intake passage;
An EGR valve that opens and closes the EGR flow path provided in the EGR flow path;
An intake valve that opens and closes between the intake port of the engine and the combustion chamber;
An exhaust valve that opens and closes between the exhaust port of the engine and the combustion chamber;
An intake / exhaust valve control unit that controls the opening of the intake valve and the exhaust valve while the engine is stopped;
A first valve control unit that performs control to close the fresh air control valve and open the EGR valve when a predetermined engine warm-up execution condition is satisfied;
When the engine warm-up execution condition is satisfied, an electric supercharger control unit that drives the electric supercharger;
A second valve control unit that adjusts an opening of the throttle valve so as to drive the electric supercharger in a predetermined drive region when the engine warm-up execution condition is satisfied;
Engine warm-up system with   The engine warm-up system according to claim 1, wherein the drive region is a region where the pressure ratio is higher and the flow rate is smaller than when the electric supercharger is normally driven. A pressure sensor for measuring a pressure downstream of the electric supercharger in the intake passage;
The second valve controller is
The engine warm-up system according to claim 1 or 2, wherein an opening degree of the throttle valve is adjusted based on a pressure measured by the pressure sensor.

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