Control device of engine system

Abstract

To provide a control device of an engine system in which an excessive rise of a temperature of a catalyst is suppressed by an easy control.SOLUTION: A control device of an engine system having an engine and a catalyst for purifying the exhaust air of the engine comprises: a determination part for performing determination processing for predicting whether or not the catalyst is excessively raised in a temperature by the execution of warmup processing for raising the temperature of the catalyst up to a warmup temperature on the basis of a temperature of the engine and the temperature of the catalyst; and a stop part for stopping the control device on the basis of a determination result. When the determination result is non-affirmative, the stop part stops the control device, when the determination result is affirmative, the determination part re-executes the determination processing, when the determination result is affirmative, and there arises an activation requirement of the engine system, the engine is started without performing the warmup processing of the catalyst, and when the determination result is non-affirmative, the control device is stopped.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control device for an engine system. [Background technology]

[0002] When the temperature of the catalyst when the engine is started is equal to or lower than a predetermined value, an ECU (Electronic Control Unit) starts the engine and executes a warm-up process to raise the temperature of the catalyst to a warm-up temperature (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-007464 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above technology, the catalyst temperature at engine start is estimated based on the length of the engine stop period and the outside air temperature during the stop period. In this method, the estimated catalyst temperature at engine start is a constant value under the same conditions of the length of the engine stop period and the same outside air temperature. However, the catalyst temperature at engine stop varies depending on the engine operating state up to that point. For this reason, there is a risk that the estimated catalyst temperature at engine start may deviate significantly from the actual temperature. As a result, for example, the estimated catalyst temperature may be estimated to be lower than the actual temperature, and the warm-up process may be performed at engine start, causing the catalyst to overheat.

[0005] In addition, the above technology requires that the measurement of the engine stop period be performed with the ECU stopped. Also, in order to obtain the outside air temperature while the engine is stopped, the ECU needs to be constantly running or be started periodically. This may complicate the control.

[0006] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a control device for an engine system that suppresses excessive temperature rise of a catalyst through simple control. [Means for solving the problem]

[0007] The object is to provide a control device for an engine system having an engine and a catalyst for purifying exhaust gas from the engine, the control device including an engine control unit that starts the engine and executes a warm-up process for raising the temperature of the catalyst to a warm-up temperature when the temperature of the engine at the initial start of the engine after the control device is activated, if the temperature of the engine is equal to or lower than the cold temperature, and stops the engine when a request to stop the engine system is made, a detection unit that detects the temperature of the engine when the stop request is made, an estimation unit that estimates the temperature of the catalyst based on the operating state of the engine from when the engine is started until the stop request is made, and ... a calculation unit that calculates the temperature of the catalyst based on the temperature of the engine and the temperature of the catalyst when the stop request is made. This can be achieved by an engine system control device comprising a judgment unit that executes a judgment process to predict whether the warm-up process will be executed and the catalyst will overheat when the engine is started for the first time after the next startup of the control device, and a stop unit that stops the control device based on the judgment result of the judgment unit, wherein if the judgment result is a negative judgment, the stop unit stops the control device, and if the judgment result is a positive judgment, the judgment unit re-executes the judgment process, and if the judgment result is a positive judgment and there is a request to start the engine system, the engine control unit starts the engine without executing the warm-up process, and if the judgment result after re-executing the judgment process is a negative judgment, the stop unit stops the control device.

[0008] In the above configuration, when there is a request to stop the engine system, it is determined based on the engine temperature and the catalyst temperature whether or not the warm-up process will be executed and the catalyst will overheat when the engine is started for the first time after the next startup of the control device. If the determination result is a positive determination and there is a request to start the engine system, the engine is started without executing the warm-up process. This prevents the catalyst from overheating due to the warm-up process.

[0009] In addition, in the above configuration, the determination process is executed again until the determination result becomes negative, and when the determination result becomes negative, the control device is stopped. In this case, if the engine temperature is equal to or lower than the cold temperature when the engine is started for the first time after the control device is started, the warm-up process is executed. As described above, it is not necessary to estimate the catalyst temperature at the next engine start in order to determine whether or not to execute the warm-up process at the next engine start. Therefore, it is not necessary to measure the engine stop period or to obtain the outside air temperature during the engine stop period. In this way, the control is simplified.

[0010] The engine system may have a motor that motors the engine with fuel injection stopped and a throttle valve open, and may also be equipped with a motoring control unit that motors the engine using the motor when the judgment result is a positive judgment.

[0011] The engine system may have a radiator that cools the engine's cooling water, and a fan that cools the radiator and the catalyst, and may be equipped with a fan control unit that drives the fan when the judgment result is a positive judgment.

[0012] When there is a stop request, if the temperature of the engine is below the cold temperature and the temperature of the catalyst is above a limit temperature lower than the warm-up temperature, the judgment unit makes a positive judgment, and when there is a stop request, if the temperature of the engine is higher than the cold temperature or the temperature of the catalyst is lower than the limit temperature, the judgment unit makes a negative judgment, and the limit temperature may be a temperature at which the catalyst overheats due to execution of a warm-up process at the first start of the engine after the next startup of the control device.

[0013] When there is a stop request and the temperature of the engine is higher than the cold temperature, the judgment unit predicts that the warm-up process will not be performed when the engine is first started after the control device is started and makes the negative judgment, and when there is a stop request and the temperature of the catalyst is lower than the limit temperature, the judgment unit predicts that the catalyst will not overheat even if the warm-up process is performed when the engine is first started after the control device is started and makes the negative judgment. Effect of the Invention

[0014] According to the present invention, it is possible to provide a control device for an engine system in which an excessive rise in temperature of a catalyst is suppressed by simple control. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a schematic configuration diagram of an engine system. [Diagram 2] FIG. 1 is a schematic diagram of an engine mounted in an engine compartment of a vehicle body. [Diagram 3] 4 is a flowchart illustrating an example of an excessive temperature rise suppression control executed by an ECU. [Figure 4] 4 is a timing chart illustrating an example of the excessive temperature rise suppression control. [Diagram 5] 4 is a timing chart illustrating an example of the excessive temperature rise suppression control. [Figure 6] 4 is a timing chart illustrating an example of the excessive temperature rise suppression control. [Figure 7]4 is a timing chart illustrating an example of the excessive temperature rise suppression control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] [General configuration of hybrid vehicle] FIG. 1 is a schematic diagram of an engine system 1. In this embodiment, the engine system 1 is mounted on a hybrid vehicle. The engine system 1 includes an ECU (Electronic Control Unit) 100, an engine 10, a first motor generator (hereinafter referred to as a "first MG (Motor Generator)") 14, a second motor generator (hereinafter referred to as a "second MG") 15, a PCU (Power Control Unit) 17, a battery 18, a power split mechanism 50, a transmission mechanism 51, a transmission 52, a drive shaft 53, a differential 54, and drive wheels 55. The engine 10 is a gasoline engine, but is not limited thereto and may be a diesel engine. The engine 10, the first MG 14, and the second MG 15 are power sources for running the hybrid vehicle.

[0017] Each of the first MG 14 and the second MG 15 has a function as a motor that outputs torque when supplied with electric power, and a function as a generator that generates regenerative electric power when torque is applied to it. The first MG 14 and the second MG 15 are electrically connected to a battery 18 via a PCU 17. The PCU 17 supplies electric power from the battery 18 to the first MG 14 or the second MG 15. The PCU 17 causes the battery 18 to receive the regenerative electric power generated in the first MG 14 or the second MG 15.

[0018] The power split mechanism 50 mechanically connects the crankshaft of the engine 10, the rotating shaft of the first MG 14, and the output shaft of the power split mechanism 50. The output shaft of the power split mechanism 50 is connected to a transmission mechanism 51. The rotating shaft of the second MG 15 is connected to the transmission mechanism 51. The transmission mechanism 51 is connected to a transmission 52. The transmission 52 is connected to a drive shaft 53. The driving forces of the engine 10, the first MG 14, and the second MG 15 are transmitted to drive wheels 55 via the transmission mechanism 51, the transmission 52, the drive shaft 53, and the differential 54.

[0019] The transmission 52 is a stepped automatic transmission provided between the second MG 15 and the drive shaft 53. The transmission 52 changes its gear ratio under the control of the ECU 100.

[0020] The ECU 100 is an electronic control unit including a calculation processing circuit that performs various calculation processes related to vehicle driving control, and a memory that stores control programs and data. The ECU 100 is an example of a control device for an engine system. The ECU 100 functionally realizes an engine control unit, a detection unit, an estimation unit, a determination unit, a stop unit, a motoring control unit, and a fan control unit, which will be described later.

[0021] The ECU 100 is electrically connected to a power switch 71, a water temperature sensor 72, a crank angle sensor 73, and an air flow meter 74. By turning the power switch 71 on and off, a ready-on state in which the engine system 1 is started and the vehicle can run, and a ready-off state in which the engine system 1 is stopped and the vehicle cannot run, are switched over. The water temperature sensor 72 detects the temperature of the coolant for the engine 10. The coolant temperature is an example of the temperature of the engine 10. The crank angle sensor 73 detects the rotation speed of the engine 10. The air flow meter 74 detects the amount of intake air for the engine 10.

[0022] When the required driving force of the engine system 1 is less than a predetermined switching value, the ECU 100 switches the driving mode of the engine system 1 to the motor driving mode. The motor driving mode is a driving mode in which at least one of the first MG 14 and the second MG 15 is used as a power source while the engine 10 is stopped. In the motor driving mode, the engine 10 is stopped. This improves fuel efficiency.

[0023] When the power switch 71 is switched from ready-on to ready-off, it is assumed that there is a request to stop the engine system 1, and the ECU 100 stops the engine 10. Thereafter, when the power switch 71 is switched from ready-off to ready-on, it is assumed that there is a request to start the engine system 1, and the ECU 100 starts the engine 10. In addition, as will be described in detail later, the ECU 100 starts the engine 10 and executes a warm-up process when a predetermined condition is met.

[0024] [Engine outline] FIG. 2 is a schematic diagram of an engine 10 mounted in an engine compartment 3 of a vehicle body 2. The engine 10 includes an engine body 10a, an intake pipe 11i, and an exhaust pipe 11e. The intake pipe 11i and the exhaust pipe 11e are connected to the engine body 10a. A throttle valve 12v that adjusts the amount of intake air is provided in the intake pipe 11i. A catalyst 12c that purifies exhaust gas is provided in the exhaust pipe 11e. A radiator 5 and a fan 6 are arranged in the engine compartment 3. The radiator 5 cools the coolant by promoting heat exchange between the coolant of the engine 10 and the outside air.

[0025] A grill shutter 4 is provided at the front of the vehicle body 2. A radiator 5 is disposed facing the grill shutter 4. A fan 6 is disposed behind the radiator 5. When the fan 6 is driven, outside air is introduced into the engine compartment 3 through the grill shutter 4. As a result, the radiator 5 is cooled. When the fan 6 is driven, the outside air flows through the engine compartment 3 and cools the catalyst 12c. That is, the fan 6 cools the radiator 5 and the catalyst 12c.

[0026] [Warm-up process] The ECU 100 starts the engine 10 when a predetermined condition is satisfied and executes a warm-up process. The warm-up process is a process for raising the temperature of the catalyst 12c to a warm-up temperature T3. The warm-up process is, for example, a process for controlling the ignition timing of the engine 10 to be retarded from the optimal ignition timing. This increases the exhaust temperature and promotes the temperature rise of the catalyst 12c. The warm-up temperature T3 is the minimum temperature at which the exhaust purification efficiency of the catalyst 12c is maintained high. The above-mentioned predetermined condition is a case where the cooling water temperature at the initial start of the engine 10 after the start of the ECU 100 is equal to or lower than the cold temperature T1. The cold temperature T1 is the maximum temperature at which the temperature of the catalyst 12c can be considered to be lower than the warm-up temperature T3. When the cooling water temperature at the initial start is equal to or lower than the cold temperature T1, the temperature of the catalyst 12c is also considered to be sufficiently low. In this way, the warm-up process is executed at the start of the engine 10, thereby raising the temperature of the catalyst 12c and reducing exhaust emissions.

[0027] As described above, when the warm-up process is performed at the start of the engine 10, the temperature of the catalyst 12c may rise excessively. Therefore, the ECU 100 executes the following control to suppress the temperature of the catalyst 12c from rising excessively.

[0028] [Overheating Suppression Control] 3 is a flowchart illustrating the overheating suppression control executed by the ECU 100. The ECU 100 determines whether or not the engine is in a ready-off state based on the power switch 71 (step S1). The ready-off state is when there is a request to stop the engine system 1, as described above. If the answer is No in step S1, this control ends. If the answer is Yes in step S1, that is, if the power switch 71 is turned from on to off, the engine 10 is stopped (step S2).

[0029] Next, the ECU 100 detects the coolant temperature and estimates the temperature of the catalyst 12c (step S3). The coolant temperature is detected based on the water temperature sensor 72. The catalyst temperature is estimated based on the operating state of the engine 10 from when the engine 10 is started until when the engine is in the ready-off state. In detail, the catalyst temperature is estimated based on an integrated value of the load on the engine 10 from when the engine 10 is started until when the engine is in the ready-off state. The larger the integrated value, the higher the catalyst temperature is estimated to be. After the engine 10 is stopped, the catalyst temperature is estimated based on the catalyst temperature estimated by the above method and the elapsed time since the engine was stopped. The longer the elapsed time since the engine was stopped, the lower the catalyst temperature is estimated to be. The catalyst temperature is estimated during the startup of the ECU 100. Step S3 is an example of a process executed by the detection unit and the estimation unit.

[0030] Next, the ECU 100 executes a determination process (step S4). The determination process is a process for predicting whether or not the catalyst 12c will overheat due to a warm-up process when the engine 10 is started for the first time after the next start of the ECU 100, based on the coolant temperature and the estimated catalyst temperature. Specifically, when the coolant temperature is equal to or lower than the cold temperature T1 and the estimated catalyst temperature is equal to or higher than a limit temperature T2 that is lower than a warm-up temperature T3, the ECU 100 determines that the catalyst 12c will overheat (hereinafter, referred to as a positive determination). This is because, when the coolant temperature is equal to or lower than the cold temperature T1, it is predicted that the warm-up process will be executed when the engine 10 is started for the first time after the next start of the ECU 100. Also, when the estimated catalyst temperature is equal to or higher than the limit temperature T2, it is predicted that the catalyst 12c will overheat due to the execution of a warm-up process when the engine 10 is started for the first time after the next start of the ECU 100. Therefore, the limit temperature T2 is the lowest temperature at which the catalyst 12c becomes overheated when the warm-up process is executed at the initial start of the engine 10 after the next start of the ECU 100.

[0031] When the cooling water temperature is higher than the cold temperature T1 or when the estimated catalyst temperature is lower than the limit temperature T2, the ECU 100 determines that the catalyst 12c will not overheat (hereinafter referred to as a negative determination). This is because, when the cooling water temperature is higher than the cold temperature T1, it is predicted that the warm-up process will not be executed when the engine 10 is started for the first time after the next start of the ECU 100. This is because, when the estimated catalyst temperature is lower than the limit temperature T2, it is predicted that the catalyst 12c will not overheat even if the warm-up process is executed when the engine 10 is started for the first time after the next start of the ECU 100. Step S5 is an example of a process executed by the determination unit.

[0032] Next, the ECU 100 judges whether the judgment result is positive (step S5). If the judgment result is No in step S5, that is, if it is judged that the catalyst 12c does not overheat, the ECU 100 stops (step S6). Step S6 is an example of a process executed by the stopping unit.

[0033] If the answer is Yes in step S5, that is, if it is determined that the catalyst 12c will overheat, the ECU 100 motors the engine 10 using the first MG 14 and drives the fan 6 (step S7). Motoring is a process in which the engine 10 is forcibly rotated by the first MG 14 with fuel injection stopped and the throttle valve 12v open. By motoring the engine 10, air is supplied from the engine 10 through the exhaust pipe 11e to the catalyst 12c. This promotes cooling of the catalyst 12c. Also, by driving the fan 6 as described above, cooling of the catalyst 12c is promoted. In this case, the ECU 100 is not stopped and is maintained in an activated state. Step S7 is an example of a process executed by the motoring control unit and the fan control unit.

[0034] Next, the ECU 100 judges whether the engine is in the ready-on state by the power switch 71 (step S8). The ready-on state is when there is a request to start the engine system 1, as described above. If the answer is Yes in step S8, the ECU 100 starts the engine 10 (step S9). The start of the engine 10 in this case does not correspond to the "initial start" of the engine 10 after the start of the ECU 100. Therefore, the engine 10 starts without executing the warm-up process. In this way, when it is predicted that the catalyst 12c will overheat, the engine 10 starts without executing the warm-up process. As a result, the overheating of the catalyst 12c is suppressed.

[0035] If the answer is No in step S8, the ECU 100 executes the process in step S3 and subsequent steps. When estimating the temperature of the catalyst 12c while the engine 10 is being motored or the fan 6 is being driven, it is desirable to estimate the temperature of the catalyst 12c taking into consideration the motoring or the driving of the fan 6. For example, when motoring or the driving of the fan 6 is being performed, it is desirable to estimate the temperature of the catalyst 12c on the assumption that the rate at which the temperature of the catalyst 12c drops while the engine 10 is stopped is higher than when these are being performed.

[0036] Therefore, if the determination result is a positive determination, motoring of the engine 10 and driving of the fan 6 are continued unless the engine is in the ready-on state. This promotes cooling of the catalyst 12c, and if it is predicted that the catalyst 12c will not overheat (No in step S5), the ECU 100 stops (step S6). By stopping the ECU 100 when the determination result is a negative determination in this manner, overheating of the catalyst 12c is suppressed even if warm-up processing is performed when the engine 10 is started for the first time after the next startup of the ECU 100.

[0037] Fig. 4 to Fig. 7 are timing charts illustrating the overheating suppression control. Fig. 4 to Fig. 7 show the start / stop state of the ECU 100, the ready on / off state, the coolant temperature, the engine speed, the execution state of the warm-up process, and the transition of the temperature of the catalyst 12c. Note that as the temperature of the catalyst 12c, the actual temperature is shown by a solid line, and the estimated temperature is shown by a dotted line. The overheating temperature T4 is the minimum temperature indicating that the catalyst 12c is in an overheating state, and is a temperature higher than the warm-up temperature T3.

[0038] FIG. 4 is a timing chart when the determination result is a positive determination and the engine 10 is then in the ready-on state. If the coolant temperature at the first start of the engine 10 after the ECU 100 is started is equal to or lower than the cold temperature T1, the warm-up process is executed (time t1). If the estimated catalyst temperature is equal to or higher than the warm-up temperature T3, the warm-up process is stopped (time t2). After that, the engine 10 is in the ready-off state and stops, but the ECU 100 does not stop (time t3). The estimated catalyst temperature at the ready-off state is equal to or higher than the limit temperature T2, and the coolant temperature is equal to or lower than the cold temperature T1. For this reason, if the ECU 100 is stopped, the warm-up process is executed at the first start of the engine 10 after the next start of the ECU 100, and it is predicted that the catalyst 12c will overheat (Yes in step S5).

[0039] After that, the engine 10 goes into a ready-on state and starts, but the warm-up process is not executed (time t4, Yes in step S8, step S9). This is because this start does not correspond to the first start after the ECU 100 is activated.

[0040] Here, in Fig. 4, the case where the ECU 100 is stopped at time t3 and started at time t4 to execute the warm-up process is shown by a broken line. If the warm-up process is executed at time t4, the actual temperature of the catalyst 12c becomes equal to or higher than the overheat temperature T4 (time t5). In this embodiment, even if the ready-off state is entered, the ECU 100 maintains the activated state, so that the engine 10 starts without executing the warm-up process when the engine is ready-on. In this way, the overheating of the catalyst 12c is suppressed. In the example of Fig. 4, the motoring of the engine 10 and the driving of the fan 6 are executed from time t3 to time t4.

[0041] 5 is a timing chart showing a case where the determination result changes from a positive determination to a negative determination. Warm-up processing is executed (time t1) and stopped (time t2). After that, the engine 10 enters a ready-off state and stops, but the ECU 100 does not stop (time t3). This is because, as in the case of FIG. 4, it is predicted that the catalyst 12c will overheat (Yes in step S5).

[0042] Thereafter, the estimated catalyst temperature falls below the limit temperature T2 and the ECU 100 is stopped (time t4, step S6). This is because it is predicted that the catalyst 12c will not overheat even if the warm-up process is executed at the initial start of the engine 10 after the next start of the ECU 100 (No in step S5). In this way, overheating of the catalyst 12c is suppressed. Note that, in the example of FIG. 5 as well, motoring of the engine 10 and driving of the fan 6 are executed from time t3 to time t4.

[0043] FIG. 6 is a timing chart showing a case where the determination result is negative. The warm-up process is executed (time t1) and stopped (time t2). After that, the engine 10 enters a ready-off state and stops, and the ECU 100 also stops (time t3, step S6). In the ready-off state, the cooling water temperature is higher than the cold temperature T1. For this reason, it is predicted that the warm-up process will not be executed when the engine 10 is started for the first time after the next start of the ECU 100 (No in step S5). After that, the engine 10 enters a ready-on state, the ECU 100 starts, and the engine 10 starts, but the cooling water temperature is higher than the cold temperature T1, so the warm-up process is not executed (time t4). In this way, the execution of the warm-up process is avoided, and thus the overheating of the catalyst 12c is suppressed.

[0044] As shown in FIG. 6, the catalyst temperature is not estimated while the ECU 100 is stopped. Also, as shown in FIG. 6, the estimated catalyst temperature at the start of the ECU 100 may deviate from the actual temperature. In this embodiment, the catalyst temperature at the start of the ECU 100 is estimated based on the coolant temperature at the start, as it is correlated with the coolant temperature at the start. That is, at the start of the ECU 100, the catalyst temperature is estimated based on the coolant temperature without considering the influence of the exhaust heat of the engine 10 that the catalyst 12c has received up to that point. For this reason, for example, if it is determined whether or not to perform the warm-up process at the start of the ECU 100 based on the estimated catalyst temperature, the warm-up process may be performed at time t4 in FIG. 6, causing the catalyst 12c to overheat. In this embodiment, the catalyst 12c is prevented from overheating because the catalyst temperature at the start of the ECU 100 is determined based on the coolant temperature at the start of the ECU 100.

[0045] 7 is a timing chart showing a case where the determination result is negative and the warm-up process is executed in the ready-on state thereafter. The warm-up process is executed (time t1) and then stopped (time t2). After that, the engine 10 enters the ready-off state, the engine 10 stops, and the ECU 100 also stops (time t3, step S6). This is because the coolant temperature is higher than the cold temperature T1 in the ready-off state, and it is predicted that the warm-up process will not be executed the first time the engine 10 is started after the next startup of the ECU 100 (No in step S5).

[0046] After that, when the ECU 100 is activated by the ready-on state and the engine 10 starts, the warm-up process is executed (time t4). This is because the cooling water temperature is below the cold temperature T1. The warm-up process then stops (time t5). In this way, when the ready-on state is entered after the cooling water temperature has dropped sufficiently, the warm-up process is executed, and exhaust emissions are reduced. When the cooling water temperature is below the cold temperature T1, the actual temperature of the catalyst 12c is also below the limit temperature T2, so even if the warm-up process is executed, excessive heating of the catalyst 12c is suppressed. Also, time t4 shows a case where the catalyst estimated temperature at the time of startup of the ECU 100 deviates from the actual temperature for the reasons described above.

[0047] As described above, the determination process is executed again until the determination result becomes negative, and when the determination result becomes negative, the ECU 100 is stopped. In this case, as shown in FIG. 7, the warm-up process is executed when the temperature of the engine 10 at the first start of the engine 10 after the start of the ECU 100 is equal to or lower than the cold temperature. As described above, in order to determine whether or not to execute the warm-up process at the next start of the engine 10, it is not necessary to estimate the temperature of the catalyst 12c at the next engine start. Therefore, it is not necessary to measure the stop period of the engine 10 or to obtain the outside air temperature during the stop period of the engine 10. In this way, the control is simplified.

[0048] As described above, the determination process is performed based on the coolant temperature and the estimated catalyst temperature in the ready-off state. By such simple control, it is possible to predict whether or not the temperature will rise excessively.

[0049] In the above embodiment, the engine system 1 mounted on a hybrid vehicle has been described as an example, but the present invention is not limited to this, and the engine system may be mounted on an engine vehicle. In this case, however, the engine 10 cannot be motored. In the above embodiment, when an overheating of the catalyst 12c is predicted, the engine 10 is motored and the fan 6 is driven, but only one of these may be performed. In the above embodiment, the temperature of the cooling water has been described as an example of the temperature of the engine 10, but the temperature of the lubricating oil may be used as the temperature of the engine 10.

[0050] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0051] 1 Engine System 5. Radiator 6 Fans 10 Engine 12c Catalyst 14 First motor generator 100 ECU (control device, engine control unit, detection unit, estimation unit, judgment unit, stop unit, motoring control unit, fan control unit)

Claims

1. A control device for an engine system having an engine and a catalyst for purifying exhaust gas from the engine, an engine control unit that starts the engine and executes a warm-up process to raise the temperature of the catalyst to a warm-up temperature when the temperature of the engine is equal to or lower than a cold temperature at the initial start of the engine after the start of the control device, and stops the engine when a stop request for the engine system is received; a detection unit that detects a temperature of the engine when the stop request is received; an estimation unit that estimates a temperature of the catalyst based on an operating state of the engine from when the engine is started until the engine is stopped when the engine is stopped; a determination unit that, when there is a stop request, executes a determination process to predict whether or not the warm-up process will be executed at the time of an initial start of the engine after the next start-up of the control device, and the catalyst will overheat; and A stop unit that stops the control device based on a determination result of the determination unit, When the determination result is a negative determination, the stop unit stops the control device, When the determination result is a positive determination, the determination unit re-executes the determination process, When the determination result is a positive determination and there is a request to start the engine system, the engine control unit starts the engine without executing the warm-up process, A control device for an engine system, wherein the stopping unit stops the control device when the determination result obtained by re-executing the determination process is a negative determination.

2. the engine system has a motor that motors the engine with fuel injection stopped and a throttle valve open; 2. The control device for an engine system according to claim 1, further comprising a motoring control unit that executes motoring of the engine by the motor when the result of the determination is affirmative.

3. the engine system includes a radiator that cools a coolant for the engine, and a fan that cools the radiator and the catalyst, 2. The control device for an engine system according to claim 1, further comprising a fan control unit that drives the fan when the result of the determination is affirmative.

4. When there is a stop request, if the temperature of the engine is equal to or lower than the cold temperature and the temperature of the catalyst is equal to or higher than a limit temperature which is lower than the warm-up temperature, the determination unit makes an affirmative determination, When there is a stop request, if the temperature of the engine is higher than the cold temperature or if the temperature of the catalyst is lower than the limit temperature, the determination unit makes a negative determination.

4. The control device for an engine system according to claim 1, wherein the limit temperature is a temperature at which the catalyst becomes overheated due to execution of a warm-up process at an initial start of the engine after the control device is next started.

5. When the stop request is received and the temperature of the engine is higher than the cold temperature, the determination unit predicts that the warm-up process will not be executed at the initial start of the engine after the control device is started, and makes the negative determination.

5. The control device for an engine system according to claim 4, wherein when there is a stop request and the temperature of the catalyst is below the limit temperature, the judgment unit predicts that the catalyst will not overheat even if the warm-up process is performed at the initial start of the engine after the control device is activated, and makes the negative judgment.

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