HYBRID VEHICLE AND METHOD FOR CONTROLLING THE HYBRID VEHICLE

Abstract

Hybrid vehicle (100) with: an internal combustion engine (1); an exhaust path (2) through which exhaust gas from the internal combustion engine (1) is released; a battery pack (7) located near the exhaust path (2); and a control device (10) which, during an emergency operation of the hybrid vehicle (100), performs a control in which the battery pack (7) is not charged and discharged, and performs a power suppression control in which the power of the internal combustion engine (1) is suppressed, wherein, When the power suppression control is in operation, if the estimated temperature of the battery pack (7) is higher than or equal to a threshold, the control device (10) suppresses the power of the internal combustion engine (1) in comparison to when the estimated temperature is lower than the threshold, while maintaining a state in which the internal combustion engine (1) can deliver power.

Description

[0001] This application is based on the Japanese patent applications JP 2019 - 164 358 A and JP 2019 - 231 890 A, which were filed on September 10, 2019 and December 23, 2019 respectively, and whose content is hereby incorporated herein in full by reference. Technical field

[0002] The present disclosure relates to a hybrid vehicle and a method for controlling the hybrid vehicle and, in particular, a technique for controlling an internal combustion engine mounted on a hybrid vehicle. State of the art

[0003] Hybrid vehicles have become popular in recent years. These vehicles are equipped with battery packs for propulsion, and various techniques have been proposed to protect them. For example, in a hybrid vehicle disclosed in JP 2008-239079A, if a battery pack malfunction is detected, the battery pack is electrically disconnected from any electrical load, including a motor-generator, so that the vehicle is powered by an internal combustion engine. If another battery pack malfunction is detected during such emergency operation, combustion engine-based propulsion is prevented.

[0004] Furthermore, DE 10 2014 205 076 A1 discloses a hybrid vehicle with an internal combustion engine, an exhaust manifold in which a catalyst is arranged, and an energy storage device. In addition, the hybrid vehicle includes a control device that performs a control operation whereby, if a certain period of time has elapsed and the catalyst has heated up to or above a threshold, the engine is throttled down and eventually switched off. If the catalyst temperature falls below the threshold, the engine is throttled up.

[0005] Furthermore, DE 690 11 824 T2 describes an alarm device that can be installed in vehicles equipped with a catalytic muffler to protect them from overheating due to an excess of unburned substances in the exhaust gases. The device consists of a second catalytic converter, which is arranged upstream of the muffler along the exhaust pipe and is equipped with a temperature sensor on its inside; if the temperature of the second converter exceeds a predetermined threshold, this is reported by the sensor, possibly to an engine control system. Summary

[0006] A hybrid vehicle equipped with a relatively large battery pack requires sufficient space for the battery pack. In such a case, the battery pack can be placed outside the passenger compartment instead of inside it.

[0007] If the battery pack is located outside the passenger compartment, particularly near the exhaust path of the combustion engine, heat from the exhaust path can be radiated onto the battery pack, causing its temperature to rise. If the battery pack temperature rises excessively, the hybrid vehicle may have to stop to protect the battery pack. To avoid this, it is preferable that the battery pack is adequately protected so that the hybrid vehicle can continue driving. A hybrid vehicle according to one aspect of the present disclosure comprises an internal combustion engine, an exhaust path through which exhaust gas from the internal combustion engine is released, a battery pack located near the exhaust path, and a control device. During emergency operation of the hybrid vehicle, the control device performs a control function in which the battery pack is neither charged nor discharged, and a power suppression control function in which the power output of the internal combustion engine is suppressed. During the power suppression control, if the estimated temperature of the battery pack is higher than or equal to a threshold, the control device suppresses the power output of the internal combustion engine, in contrast to when the estimated temperature is lower than the threshold, while maintaining a state in which the internal combustion engine can deliver power. The hybrid vehicle also features a drive unit that powers a drive motor and a relay that is electrically connected between the battery pack and the drive unit. During emergency operation, the control unit opens the relay, thus electrically disconnecting the battery pack from the drive unit. The exhaust system includes a catalytic converter to clean the exhaust gases. The hybrid vehicle also has a sensor that outputs the temperature of the catalytic converter. The control unit uses this catalytic converter temperature as the estimated temperature. The exhaust system includes a catalytic converter for cleaning the exhaust gases. The hybrid vehicle also has a sensor that outputs an operating status reading for the combustion engine. The control unit estimates the temperature of the catalytic converter based on the sensor output and uses this temperature as the estimated temperature. The battery pack comprises a composite battery, a cooling system that cools the composite battery, and a junction box that is not cooled by the cooling system. The hybrid vehicle also features a sensor that outputs the temperature of the composite battery as an estimated temperature.

[0008] In the configuration of aspects (1) to (5) mentioned above, the control unit, during power suppression control, suppresses the internal combustion engine's power output when an estimated temperature (the temperature of a catalyst or the temperature of a composite battery) is higher than or equal to a threshold, in contrast to when the estimated temperature is lower than the threshold, while maintaining a state in which the internal combustion engine can deliver power. Specifically, while the battery pack is electrically disconnected from the drive system, the hybrid vehicle relies solely on the internal combustion engine's power for propulsion. This results in a greater amount of radiant heat from the exhaust pipe and therefore likely causes a greater temperature increase in the battery pack.Suppressing the combustion engine's power output reduces the further temperature increase of the exhaust path, thus preventing an excessive temperature rise of the battery pack (or the components within the battery pack) that would be caused by radiant heat from the exhaust path. Therefore, according to the configuration of the aforementioned aspects (1) to (5), the battery pack can be protected while the hybrid vehicle can continue driving.

[0009] (6) The control device shall perform power suppression control if a condition in which the estimated temperature is higher than or equal to the threshold lasts longer than a first predetermined time.

[0010] If an increase in the estimated temperature is only temporary, no excessive temperature rise of the battery pack will occur. Accordingly, in the configuration of the aforementioned aspect (6), the power suppression control is only executed if the estimated temperature remains higher than or equal to a threshold value. This can prevent excessive suppression of the combustion engine power, which does not contribute to preventing a temperature rise of the battery pack.

[0011] (7) If the speed of the hybrid vehicle is higher than a first predetermined speed, the control unit delays the start of the execution of the power suppression control compared to when the speed of the hybrid vehicle is equal to or less than the first predetermined speed.

[0012] A higher vehicle speed causes a stronger airflow against the battery pack. Since a vehicle speed greater than the first preset speed allows the airflow to cool the battery pack sufficiently, the start time of the power suppression control is preferably determined taking this cooling effect into account. According to the configuration of aspect (7) mentioned above, the control unit delays the start of the power suppression control when the vehicle speed is higher than the first preset speed, compared to when the vehicle speed is equal to or less than the first preset speed. This can prevent the power suppression control from executing if the battery pack has already been cooled.

[0013] (8) If the estimated temperature after suppression of the internal combustion engine power falls below a further threshold that is smaller than the threshold, the control device stops the power suppression control.

[0014] If the estimated temperature falls below a further threshold, i.e., if the estimated temperature has decreased, the power suppression control is stopped (disabled) to protect the battery from excessive temperature rise. Thus, the hybrid vehicle can restore its driving performance according to the configuration of the aforementioned aspect (8).

[0015] (9) If a condition in which the estimated temperature is less than the further threshold lasts longer than a second predetermined time after the start of the suppression of internal combustion engine power, the control device stops the power suppression control.

[0016] If the power suppression control is stopped even though the estimated temperature only temporarily decreases, an excessive temperature rise of the battery pack may not be prevented. Accordingly, in the configuration described above, the power suppression control is only stopped if the estimated temperature remains below the other threshold. This can more reliably prevent an excessive temperature rise of the battery pack.

[0017] (10) If the speed of the hybrid vehicle is higher than a second preset speed, the control unit will accelerate a stop of the power suppression control compared to when the speed of the hybrid vehicle is equal to or less than the second preset speed.

[0018] According to the configuration of the aforementioned aspect (10), if the vehicle speed is higher than the second preset speed, the control unit accelerates the stopping of the power suppression control compared to when the vehicle speed is equal to or less than the second preset speed. This can prevent the power suppression control from continuing if the battery pack has already been cooled.

[0019] (11) The control device increases the degree of suppression of the internal combustion engine's power output with an increase in the estimated temperature.

[0020] A higher estimated temperature results in a greater amount of radiant heat from the exhaust path and therefore likely causes a greater temperature increase in the battery pack. Thus, in the configuration of the aforementioned aspect (11), the degree of suppression of combustion engine power increases with an increase in the estimated temperature. This can more reliably prevent an excessive temperature increase in the battery pack.

[0021] (12) The control device reduces the degree of suppression of the internal combustion engine's power output as the vehicle speed of the hybrid vehicle increases.

[0022] The hybrid vehicle, traveling at a higher speed, generates a stronger airflow against the battery pack, resulting in greater heat radiation from the battery pack. Consequently, the battery pack temperature is less likely to rise despite the radiant heat from the exhaust pipe. As a result, there is less need to suppress the combustion engine's power output. Accordingly, in the configuration of the aforementioned aspect (12), the degree of combustion engine power suppression decreases as the vehicle speed increases. This can prevent the hybrid vehicle from experiencing an excessive reduction in driving performance.

[0023] (13) The hybrid vehicle also has a notification device that notifies a user of the hybrid vehicle that the power suppression control is being executed.

[0024] According to the configuration of the aforementioned aspect (13), the user receiving the notification can recognize that the power reduction control is being executed. This can reduce the user's feeling of discomfort that would be caused by the reduction in the hybrid vehicle's driving performance.

[0025] (14) In the case of power suppression control, if the estimated temperature is higher than or equal to the threshold, the control device reduces a power limit of the internal combustion engine compared to when the estimated temperature is lower than the threshold.

[0026] (15) In the case of power suppression control, if the estimated temperature is higher than or equal to the threshold, the control device reduces the requested power for a given accelerator pedal position compared to when the estimated temperature is lower than the threshold.

[0027] According to the configuration of the aforementioned aspects (14) and (15), the power suppression control can be implemented by reducing the power limit or the required power of the combustion engine. This prevents an excessive temperature increase of the battery pack.

[0028] (16) A hybrid vehicle according to a further aspect of the present disclosure comprises: an internal combustion engine; an exhaust path comprising a catalyst for cleaning exhaust gas from the internal combustion engine and through which the cleaned exhaust gas is released; a battery pack located near the exhaust path; and a control device. During emergency operation of the hybrid vehicle, the control device performs a control in which the battery pack is not charged and discharged, and a power suppression control in which the power output of the internal combustion engine is suppressed.In the power reduction control system, if a condition in which the catalyst temperature is higher than or equal to a threshold value persists for a predetermined time, the control unit reduces the engine's power output to a power ceiling greater than zero. This is in contrast to when the catalyst temperature is lower than the threshold, while maintaining a state in which the engine can deliver power. With the power reduction control system, the degree of reduction of the power ceiling increases with an increase in the catalyst temperature.

[0029] According to the configuration of the aforementioned aspect (16), the battery pack can be protected while the hybrid vehicle can continue driving, as with the configuration of the aforementioned aspect (1).

[0030] (17) In a control method for a hybrid vehicle according to another aspect of the present disclosure, the hybrid vehicle has an internal combustion engine, an exhaust path through which exhaust gas from the internal combustion engine is released, and a battery pack located near the exhaust path. The control method has the following first and second steps. The first step involves sensing an estimated temperature of the battery pack. The second step involves controlling the battery pack during emergency operation of the hybrid vehicle to prevent it from being charged and discharged, and, if the estimated temperature is higher than or equal to a threshold, suppressing the power output of the internal combustion engine, in contrast, if the estimated temperature is lower than the threshold, while maintaining a state in which the internal combustion engine can deliver power.

[0031] According to the procedure of the aforementioned aspect (17), the battery pack can be protected while the hybrid vehicle can continue driving, as in the configuration of the aforementioned aspect (1).

[0032] The foregoing and other items, features, aspects and advantages of the present disclosure will become clearer from the following detailed description of the present disclosure in conjunction with the accompanying drawings. Brief description of the drawings Fig. Figure 1 is a block diagram that schematically shows a general configuration of a hybrid vehicle in embodiment 1. Fig. Figure 2 is a view showing an exemplary layout of an internal combustion engine, an exhaust pipe, and a battery pack. Fig. Figure 3 is a diagram illustrating an example of power suppression control. Fig. Figure 4 is a diagram illustrating another example of power suppression control. Fig. Figure 5 is a timing diagram to illustrate the power control of the internal combustion engine in embodiment 1. Fig. Figure 6 is a flowchart showing the license plate control of the internal combustion engine in embodiment 1. Fig. Figure 7 is a flowchart showing the power control of the internal combustion engine in embodiment 1. Fig. Figure 8 is a diagram illustrating the dependence of the power limit on the catalyst temperature and the vehicle speed. Fig. Figure 9 is a flowchart showing the power suppression control in variation 1 of embodiment 1. Fig. Figure 10 is a graph illustrating an example of power suppression control in variation 2 of embodiment 1. Fig. Figure 11 is a flowchart that schematically shows a general configuration of a hybrid vehicle in embodiment 2. Fig. Figure 12 is a flowchart showing the license plate control of the internal combustion engine in embodiment 2. Fig. Figure 13 is a timing diagram to explain the power control of the internal combustion engine in embodiment 3. Fig. Figure 14 is a flowchart showing the license plate control of the internal combustion engine in embodiment 3. Fig. Figure 15 is a flowchart showing the power control of the internal combustion engine in embodiment 3. Description of preferred embodiments

[0033] The present embodiments are now described in detail with reference to the drawings. In the drawings, the same or corresponding parts are marked with the same reference numerals, and the description of such parts is not repeated. Example 1<Konfiguration des Hybridfahrzeugs>

[0034] Fig. Figure 1 is a block diagram that schematically shows a general configuration of a hybrid vehicle 1 in embodiment 1. With reference to Fig. In this embodiment, 1 is a hybrid vehicle 100, a hybrid vehicle (HV). However, the hybrid vehicle 100 can be a plug-in hybrid vehicle (PHV), which can be charged with electrical energy from outside the hybrid vehicle.

[0035] The hybrid vehicle 100 includes an internal combustion engine 1, an exhaust path 2, a first motor generator (MG) 31, a drive motor / second motor generator (MG) 32, a drive power distribution device 33, an output shaft 41, a drive wheel 42, a power control unit / drive device (PCU) 5, a relay / system main relay (SMR) 6, a battery pack 7, a notification device / human-machine interface (HMI) 8, an accelerator pedal position sensor 91, a vehicle speed sensor 92, and a control device / electronic control unit (ECU) 10. The ECU 10 includes a hybrid ECU 101, an internal combustion engine ECU 102, and a battery ECU 103.

[0036] The internal combustion engine 1 burns fuel based on the control signal from the internal combustion engine ECU 102 to output the drive power. The internal combustion engine 1 is, for example, a gasoline engine or a diesel engine. When the first MG 31 is cranked, the internal combustion engine 1 starts and supplies drive power to the first MG 31 and / or the output shaft 41 via the drive power distribution device 33.

[0037] Exhaust path 2 enables the release of exhaust gas from the combustion engine 1 of the hybrid vehicle. Exhaust path 2 includes an exhaust pipe 21 and a catalyst temperature sensor 22. The exhaust pipe 21 has a catalytic device 211, a filter 212, and an exhaust silencer 213 along the exhaust gas flow path.

[0038] The catalytic device 211 oxidizes and reduces one unburned component (e.g., hydrocarbon (HC) or carbon monoxide (CO)) and one oxidation component (e.g., nitrogen oxides (NOx)) contained in the exhaust gas from the combustion engine 1. The filter 212 collects particulate matter (PM) from the combustion engine 1. The filter 212 is a gasoline particulate filter (GPF) if the combustion engine 1 is a gasoline engine, or a diesel particulate filter (DPF) if the combustion engine 1 is a diesel engine. The exhaust silencer 213 reduces noise (exhaust noise) generated when the exhaust gas is released from the hybrid vehicle. The exhaust pipe 21 corresponds to the "exhaust path" in the present disclosure.

[0039] The catalyst temperature sensor 22 detects the bed temperature of the catalyst contained in the catalytic device 211 (hereinafter also referred to as "catalyst temperature Tc") and outputs the result of the detection to the internal combustion engine ECU 102.

[0040] Both the first MG 31 and the second MG 32 are AC electric motors, for example, three-phase AC permanent magnet synchronous motors. The first MG 31 can generate electrical energy by using the drive power from the internal combustion engine 1, which is received by the drive power distribution device 33. For example, when the state of charge (SOC) of the battery pack 7 reaches a predetermined lower limit, the internal combustion engine 1 starts and the first MG 31 generates electrical energy. The electrical energy generated by the first MG 31 undergoes a voltage conversion by the PCU 5 so that the energy is either stored in the battery pack 7 or supplied directly to the second MG 32.

[0041] The second MG 32 generates a driving force by using the electrical power stored in the battery pack 7 and / or the electrical power generated by the first MG 31. The driving force from the second MG 32 is transmitted to the drive wheel 42 via the output shaft 41. When the hybrid vehicle 100 brakes, the second MG 32 is driven by the drive wheel 42 and thus acts as a regenerative brake, converting the braking energy into electrical energy. The electrical energy generated by the second MG 32 is stored in the battery pack 7.

[0042] The drive power distribution device 33 is configured to divide the drive power from the internal combustion engine 1 into drive power for driving the drive wheel 42 and drive power for driving the first machine gun 31. The drive power distribution device 33 is, for example, a planetary gear mechanism comprising a sun gear S, a planet gear P, a ring gear R, and a carrier C.

[0043] The PCU 5 converts the high-voltage direct current supplied by battery pack 7 into alternating current and outputs it to the first MG 31 and / or the second MG 32 based on the control signal from the hybrid ECU 101. This powers the first MG 31 and / or the second MG 32. The PCU 5 also converts the alternating current generated by the first MG 31 and / or the second MG 32 into direct current and outputs this to battery pack 7. This charges battery pack 7. The PCU 5 can also power the second MG 32 using the electrical energy generated by the first MG 31.

[0044] The SMR 6 is electrically connected between the PCU 5 and the battery pack 7. The SMR 6 electrically connects and disconnects the battery pack 7 from the PCU 5, based on the control signal from the hybrid ECU 101.

[0045] The battery pack 7 stores high-voltage direct current to drive the first MG 31 and / or the second MG 32. The battery pack 7 comprises a composite battery 71. Each cell that forms the composite battery is a secondary battery, such as a nickel-metal hydride secondary battery or a lithium-ion secondary battery.

[0046] The HMI 8 sends and receives signals to and from the hybrid ECU 101. The HMI 8 provides various types of information about the hybrid vehicle 100 to a user (typically a driver) of the hybrid vehicle 100 and receives user input. The HMI 8 includes an instrument panel, a head-up display, a touchscreen for a car navigation system, a smart speaker, and similar components, none of which are shown.

[0047] The accelerator pedal position sensor 91 detects the degree of depressurization of the accelerator pedal generated by the user as an accelerator pedal position (Acc) and outputs the detection result to the hybrid ECU 101. The vehicle speed sensor 92 detects the rotational speed of the output shaft 41 as a vehicle speed (V) and outputs the detection result to the hybrid ECU 101.

[0048] The hybrid ECU 101, the combustion engine ECU 102, and the battery ECU 103 each contain a central processing unit (CPU), memory, and an input / output interface, none of which are shown. Each ECU executes a predefined calculation process based on the information stored in its memory and the data from a corresponding sensor. The hybrid ECU 101, the combustion engine ECU 102, and the battery ECU 103 are connected via a communication line 19. The hybrid ECU 101 performs overall control of the hybrid vehicle 100 through bidirectional communication with the combustion engine ECU 102 and the battery ECU 103.

[0049] In particular, the hybrid ECU 101 calculates a drive force (user-requested power) that the user requests from the hybrid vehicle 100 to generate the vehicle speed V, etc., based on the accelerator pedal position Acc. The hybrid ECU 101 generates and outputs an internal combustion engine command signal to the internal combustion engine ECU 102 and also generates and outputs a first MG command signal and a second MG command signal to the PCU 5 so that the user-requested power can be transmitted to the drive wheel 42. Thus, the internal combustion engine ECU 102 controls the power of the internal combustion engine 1 (in particular the throttle position, ignition timing, and amount of fuel injection, etc.) so that the internal combustion engine power matches the power requested by the internal combustion engine command signal. Furthermore, the PCU 5 controls the power outputs of the first MG 31 and the second MG 32 (in particular the current amounts, etc.).) each according to the first MG command signal and the second MG command signal from the hybrid ECU 101.

[0050] In this embodiment, the hybrid ECU 101 controls the hybrid vehicle 100 when a malfunction (e.g., an overvoltage) occurs in the battery pack 7 to perform an emergency operation (limp mode) in which the electrical energy in the battery pack 7 is not used. This emergency operation is referred to below as "battery-less driving." During battery-less driving, the hybrid ECU 101 controls the SMR 6 to OFF (open state) to electrically disconnect the battery pack 7 from the PCU 5. This state is referred to as the "battery-less state." In the battery-less state, the hybrid ECU 101 controls the hybrid vehicle 100 to use the power of the internal combustion engine 1 for driving. In the battery-less state, the hybrid ECU 101 can control the hybrid vehicle 100 to drive by powering the second MG 32 with the electrical energy generated by the first MG 31, using the power of the internal combustion engine 1.

[0051] While the ECU 10 in Fig. Since ECU 1 is divided into three units, the division of ECU 10 is not essential. In contrast, ECU 10 can be divided into several (four or more) units according to its function. For the sake of brevity, in the following description, the hybrid ECU 101, the internal combustion engine ECU 102, and the battery ECU 103 can simply be referred to as "ECU 10" without distinction. <Layout des Akkupacks>

[0052] Fig. Figure 2 is a view showing an exemplary layout of the internal combustion engine 1, the exhaust pipe 21 and the battery pack 7. Fig. Figure 2 shows a bottom view of the Hybrid Vehicle 100. With reference to Fig. The combustion engine 1 is located in an engine compartment at the front of the hybrid vehicle 100. The exhaust silencer 213 is located at the rear of the hybrid vehicle 100. The exhaust pipe 21 extends longitudinally along the hybrid vehicle 100.

[0053] In this example, the battery pack 7 is mounted under the floor outside the passenger compartment and is located near the exhaust pipe 21. Since the space between the battery pack 7 and the exhaust pipe 21 is narrow, the waste heat from the combustion engine 1 and the radiation from the exhaust pipe 21 heat the battery pack 7 while the hybrid vehicle 100 is in motion. A temperature increase of the battery pack 7 can also occur while the hybrid vehicle 100 is driving without battery power.

[0054] In the ground view of Fig. In Figure 2, the battery pack 7 is located on the right and the exhaust pipe 21 on the left. However, the battery pack 7 could be located in a different position, which could be affected by the radiant heat from the exhaust pipe 21. The layout of the battery pack 7 and the exhaust pipe 21 is not shown in Figure 2. Fig. 2 shown limited. <Leistungsunterdrückungssteuerung>

[0055] In this embodiment, a "power suppression control" is implemented, in which the power output of the combustion engine 1 is suppressed compared to normal operating times in order to adequately protect the battery pack 7 from the waste heat generated by the combustion engine 1, while still allowing the hybrid vehicle 100 to continue driving without battery power. By implementing the power suppression control, the heat radiation from the exhaust pipe 21 to the battery pack 7 can be reduced compared to when the power suppression control is not implemented (during normal operating times), thereby suppressing a temperature increase of the battery pack 7. This prevents an excessive temperature rise of the battery pack 7, thus protecting it.

[0056] Fig. Figure 3 is a diagram illustrating an example of power suppression control. The power of the internal combustion engine 1 is controlled to be a lower limit of the required power Preq to be generated by the internal combustion engine 1, and the upper limit of the power of the internal combustion engine 1 (hereinafter also referred to as the "power limit Plim").

[0057] In the Fig. 3 and the one described later Fig. 4. The power limit Plim is determined according to the catalyst temperature Tc. The horizontal axis shows the catalyst temperature Tc and the vertical axis shows the power limit Plim. The corresponding ratio between the catalyst temperature Tc and the power limit Plim, as shown in Fig. 3 shown is predefined and stored as a map MP1 in the memory of ECU 10; or the corresponding ratio, as shown in Fig. As shown in Figure 4, the map MP2 is stored in the memory of ECU 10. ECU 10 can determine the power limit Plim from the catalyst temperature Tc by referencing either map MP1 or map MP2.

[0058] In the Fig. In example 3, the catalyst temperature Tc is divided into four temperature ranges. These four temperature ranges consist of: the temperature range of less than T1, the temperature range of not less than T1 and less than T2, the temperature range of not less than T2 and less than T3, and the temperature range of not less than T3.

[0059] In the temperature range below T1, the power output of combustion engine 1 is not limited by the power limit Plim (i.e., the power suppression control is not executed), and the power limit Plim is P0 (e.g., P0 = 131 kW). In contrast, in the temperature range above T1, the power suppression control is executed. In the temperature range below T1 and below T2, the power limit Plim = P1 (e.g., P1 = 70 kW) is met. In the temperature range below T2 and below T3, the power limit Plim = P2 (e.g., P2 = 60 kW) is met. In the temperature range below T3, the power limit Plim = P3 (e.g., P3 = 50 kW) is met.

[0060] Thus, in temperature ranges of at least T1, power suppression control is implemented, whereby the degree of reduction of the power limit Plim increases with an increase in the catalyst temperature Tc. Accordingly, compared to the power limit Plim without power suppression control, a higher degree of reduction of the power limit Plim means that the power of the combustion engine 1 more easily reaches the power limit Plim and is therefore more easily limited by it. This, in turn, leads to a reduction in the waste heat from the combustion engine 1 and consequently to a reduction in radiant heat from the exhaust pipe 21, thereby highly effectively suppressing a temperature increase in the catalyst temperature Tc. Therefore, the battery pack 7 can be effectively protected from an excessive temperature increase.In contrast, in a stage where the catalyst temperature Tc has not increased so significantly (e.g., where the catalyst temperature Tc is in the temperature range of no less than T1 and less than T2), the degree of reduction of the power limit Plim is relatively small, so that the emergency operating capability of the hybrid vehicle 100 can be ensured.

[0061] Dividing the catalyst temperature Tc into four temperature ranges as in Fig. Figure 3 is just one example. The catalyst temperature Tc can be divided into two temperature ranges. In this case, the catalyst temperature Tc is divided into a temperature range in which power suppression control is active and a temperature range in which power suppression control is not active. Alternatively, the catalyst temperature Tc can be divided into three, five, or more temperature ranges.

[0062] Fig. Figure 4 is a diagram illustrating another example of power suppression control. In the diagram shown... Fig. In the example shown in 4, the power limit Plim decreases linearly in a temperature range of not less than T1 as the catalyst temperature Tc increases.

[0063] Thus, the mode for suppressing the power of the internal combustion engine 1 is not limited to the stepwise change, as in Fig. 3 shown, but it can be any other mode as long as the power limit Plim decreases monotonically with increasing catalyst temperature Tc. For example, the power limit Plim can be linear, as in Fig. 4 shown, or modified curvilinearly, although this is not shown. <Zeitdiagramm der Verbrennungsmotorsteuerung>

[0064] Fig. Figure 5 is a timing diagram illustrating the power control of the internal combustion engine 1 in embodiment 1. With reference to Fig. Figure 5 shows the elapsed time on the horizontal axis. The vertical axis shows the catalyst temperature Tc, the high-temperature counter value, the cooling counter value, the ON / OFF status of the high-temperature detection indicator, the ON / OFF status of the cooling detection indicator, and the ON / OFF status of the power suppression request, in that order from top to bottom.

[0065] For the catalyst temperature Tc, a first threshold TH1 and a second threshold TH2 are specified. The first threshold TH1 defines a high catalyst temperature Tc. The second threshold TH2 defines a normal catalyst temperature Tc. For example, the first threshold TH1 is 900°C and the second threshold TH2 is 700°C.

[0066] For the high-temperature counter (hereinafter referred to as "high-temperature counter value X1"), a first reference value REF1 is specified, which determines whether the catalyst temperature Tc is high. For the cooling counter (hereinafter referred to as "cooling counter value X2"), a second reference value REF2 is specified, which determines whether the catalyst temperature Tc has already cooled down. For example, the high-temperature counter value X1 is a count corresponding to four hours, and the cooling counter value X2 is a count corresponding to one hour.

[0067] The power suppression request is a request from the hybrid ECU 101 to the internal combustion engine ECU 102 when the hybrid ECU 101 determines that the power of internal combustion engine 1 must be suppressed. In response to the power suppression request from the hybrid ECU 101, the internal combustion engine ECU 102 controls internal combustion engine 1 to suppress its power.

[0068] In the Fig. In the example shown, hybrid vehicle 100 performs the battery-less driving at time t10. The catalyst temperature Tc at time t10 is a temperature between the first threshold TH1 and the second threshold TH2. The high-temperature counter X1 and the cooling counter X2 are both 0. The high-temperature determination indicator and the cooling determination indicator are both OFF. Furthermore, the power suppression request is OFF.

[0069] The continuous power output of the combustion engine 1 causes the catalyst temperature Tc to rise above the first threshold TH1 at time t11. The high-temperature count X1 is then increased for the period during which the catalyst temperature Tc remains above the first threshold TH1.

[0070] The high-temperature counter value X1 continues to increase until time t12, when the first reference value REF1 is reached. If the catalyst temperature Tc is maintained at a high temperature equal to or greater than the first threshold TH1, it is likely that the battery pack 7 is at a high temperature due to radiant heat from the exhaust pipe 21. Therefore, the high-temperature determination indicator is switched from OFF to ON. In response to the high-temperature determination indicator being switched ON, the hybrid ECU 101 issues a power reduction request to the internal combustion engine ECU 102.

[0071] Upon receiving the power suppression request from the hybrid ECU 101, the internal combustion engine ECU 102 reduces the power limit Plim of the internal combustion engine 1 compared to before receiving the power suppression request (see Fig. 3 or Fig. 4).

[0072] Then the power output of combustion engine 1 decreases, which in turn reduces the catalyst temperature Tc, so that the catalyst temperature Tc falls below the second threshold TH2 at time t13. Then the cooling counter value X2 is increased during the period in which the catalyst temperature Tc is below the second threshold TH2.

[0073] When the cooling counter value X2 reaches the second reference value REF2 at time t14, the cooling determination indicator is switched from OFF to ON. In response, the output of the power suppression request from the hybrid ECU 101 to the internal combustion engine ECU 102 is stopped (i.e., the power suppression control is deactivated). Afterwards, the high-temperature counter value X1 and the cooling counter value X2 are reset, and the high-temperature determination indicator and the cooling determination indicator are switched to OFF (time t15).

[0074] The catalyst temperature Tc corresponds to the “estimated temperature” in the present disclosure. In the Fig. In the example shown in Figure 5, the first threshold TH1 corresponds to the “threshold” in the present disclosure, and the period from time t11 to time t12 corresponds to the “first predetermined time” in the present disclosure. It should be noted that, as shown in the flowcharts described later, the feature “a state in which the estimated temperature is above the threshold for a period longer than a first predetermined time” in the present disclosure is not limited to a situation in which the catalyst temperature Tc is constantly above the first threshold TH1. The catalyst temperature Tc can change within the temperature range between the first threshold TH1 and the second threshold TH2, as long as the catalyst temperature Tc does not fall below the second threshold TH2.If the catalyst temperature Tc is temporarily above the first threshold TH1 in this way, the integrated value of the time during which the catalyst temperature Tc is above the first threshold TH1 can be defined as the “first predetermined time” in the present disclosure.

[0075] The second threshold TH2 corresponds to “a further threshold” in the present disclosure, and the period from time t13 to time t14 corresponds to the “second predetermined time” in the present disclosure. As with the “first predetermined time,” the “second predetermined time” can also be the integrated value of the time during which the catalyst temperature Tc is below the second threshold TH2. <Ablaufdiagramm der Verbrennungsmotorsteuerung>

[0076] Fig. Figure 6 is a flowchart showing the license plate control of internal combustion engine 1 in embodiment 1. The flowcharts of Fig. 6 and the one described later Fig. 12 and Fig. Step 14 is implemented by a program that is pre-stored in the memory of ECU 10 and called by a main routine (not shown) in a predefined control cycle. It should be noted that some or all of the processes of the steps can be implemented by dedicated hardware (electronic circuitry). Hereinafter, the steps are abbreviated as "S".

[0077] In relation to Fig. At S101, ECU 10 determines whether the hybrid vehicle 100 performs the battery-less driving procedure or not. If the hybrid vehicle 100 does not perform the battery-less driving procedure (NO at S101), the process returns to the main routine.

[0078] When the hybrid vehicle 100 performs the battery-less driving (JA at S101), the ECU 10 receives the catalyst temperature Tc, which is detected by the catalyst temperature sensor 22 (S102). The catalyst temperature Tc obtained during a specific period is temporarily stored in the memory of the ECU 10 to be used for determining the power limit Plim.

[0079] At S103, the ECU 10 determines whether the catalyst temperature Tc is equal to or greater than the first threshold TH1. The first threshold TH1 is predetermined based on the corresponding ratio between the catalyst temperature Tc and the temperature of the battery pack 7. Specifically, this corresponding ratio is obtained experimentally by taking into account the time delay between the start of the suppression of the combustion engine 1's power and the start of the decrease in the battery pack 7's temperature. This is because, due to the heat capacities of the exhaust pipe 21 and the battery pack 7, the temperature of the battery pack 7 does not necessarily decrease immediately after the suppression of the combustion engine 1's power. A temperature is determined that the battery pack 7 preferably does not exceed, in order to protect the battery pack 7.The catalyst temperature Tc, which corresponds to the specified temperature, can be set to the first threshold TH1.

[0080] If the catalyst temperature Tc is equal to or greater than the first threshold TH1 (JA at S103), the ECU 10 increases the high-temperature counter value X1 (S104) (see time t11 in Fig. 5). The ECU 10 resets the cooling counter value X2 to 0.

[0081] At S105, ECU 10 determines whether the high-temperature count X1 is equal to or greater than the first reference value REF1. The first reference value REF1 can be determined as follows: If an increase in the catalyst temperature Tc is only temporary, no excessive temperature increase of the battery pack 7 occurs because there is a time lag between an increase in the catalyst temperature Tc and an increase in the temperature of the battery pack 7. Accordingly, the first reference value REF1 is experimentally determined as a period such that if the catalyst temperature Tc remains equal to or greater than the first threshold TH1 for this period, the temperature of the battery pack 7 would rise significantly (e.g., four hours). The determined period is then subdivided by the control cycle of a series of processes.

[0082] If the high-temperature counter value X1 is less than the first reference value REF1 (NO at S105), ECU 10 returns the process to the main routine. The high-temperature counter value X1 is then further incremented for the period in which the catalyst temperature Tc is equal to or greater than the first threshold TH1. When the high-temperature counter value X1 becomes equal to or greater than the first reference value REF1 (YES at S105), ECU 10 switches the high-temperature determination indicator from OFF to ON (S106) (see time t12 in Fig. 5) In response, the power suppression control is executed. If ECU 10 is not executing the power suppression control, ECU 10 initiates the power suppression control; whereas if ECU 10 is executing the power suppression control, ECU 10 continues the power suppression control.

[0083] If the catalyst temperature Tc detected at S102 is less than the first threshold TH1 (NO at S103), ECU 10 advances the process to S107 and determines whether the high-temperature determination indicator is ON or not. A determination of "NO" at S103 is not limited to a case where the catalyst temperature Tc increases to turn the high-temperature determination indicator ON and then decreases as a result of power suppression control. A determination of "NO" at S103 can also be a case where no power suppression control is executed (e.g., a case where the catalyst temperature Tc did not rise above the first threshold TH1, or a case where the catalyst temperature Tc rose, but only temporarily, and decreased without power suppression control being executed).

[0084] If the high-temperature determination indicator is OFF (NO in S107), the ECU 10 retains the high-temperature counter value X1 and the cooling counter value X2 (S108). The process then returns to the main routine.

[0085] If the high-temperature determination indicator is ON (YES for S107), the ECU 10 determines whether the catalyst temperature Tc is equal to or less than the second threshold TH2 (S109). The second threshold TH2 can be determined to be a catalyst temperature Tc that is experimentally verified to reduce the temperature of battery pack 7 to a level that protects it.

[0086] While the catalyst temperature Tc is above the second threshold TH2 during the execution of the power suppression control (NO at S109), the cooling counter value X2 is maintained. The high-temperature counter value X1 is also held at a value during the counting process without being reset (S114). Then ECU 10 returns the process to the main routine.

[0087] If the catalyst temperature Tc becomes equal to or less than the second threshold TH2 (YES at S109), the ECU 10 increases the cooling counter value X2 (S110) (see time t13 in Fig. 5).

[0088] At S111, ECU 10 determines whether the cooling counter value X2 is equal to or greater than the second reference value REF2. The second reference value REF2 can be set by subdividing a period of time, based on which a decrease in the catalyst temperature Tc can be determined to be non-temporary (e.g., one hour), through the control cycle of the process.

[0089] If the cooling counter value X2 is less than the second reference value REF2 (NO at S111), ECU 10 returns the process to the main routine. The cooling counter value X2 is then incremented until the second reference value REF2 is reached during the period in which the catalyst temperature Tc is equal to or greater than the second threshold TH2. If the cooling counter value X2 becomes equal to or greater than the second reference value REF2 (YES at S111), ECU 10 switches the cooling determination indicator from OFF to ON (S112) (see time t14 in Fig. 5) In response, the power suppression control is stopped (i.e., power suppression is lifted). Then, ECU 10 switches the high-temperature determination indicator and the cooling determination indicator off and resets the high-temperature counter value X1 and the cooling counter value X2 (S113) (see time t15 in Fig. 5).

[0090] Fig. Figure 7 is a flowchart showing the power control of internal combustion engine 1 in embodiment 1. With regard to Fig. 7 the ECU 10 calculates a preliminary value of the demand power Preq for the internal combustion engine 1 at S201 based on the accelerator pedal position Acc detected by the accelerator pedal position sensor 91 and the vehicle speed V detected by the vehicle speed sensor 92.

[0091] At S202, ECU 10 determines whether the high-temperature determination indicator is ON or not. If the high-temperature determination indicator is OFF and the power suppression control is not executed (No at S202), ECU 10 sets the requested power Preq, calculated at S201, as the requested power for internal combustion engine 1 (S210).

[0092] If the high-temperature determination indicator is ON (YES at S202), ECU 10 determines whether the cooling determination indicator is ON or not (S203). If the high-temperature determination indicator is ON while the cooling determination indicator is OFF (NO at S203), ECU 10 proceeds to S206.

[0093] In S206, the ECU 10 reads the catalyst temperature Tc stored in memory and calculates the average value of the catalyst temperature Tc in the last specified period (e.g. one hour).

[0094] In the S207, the ECU 10 determines the power limit Plim, which corresponds to the average value of the catalyst temperature Tc, in relation to the map MP1 (see Fig. 3) The ECU 10 can use the MP2 map (see Fig. 4) Use the MP1 map instead.

[0095] At S208, the ECU 10 compares the demand power Preq calculated at S201 with the power limit Plim and determines a lower demand power Preq and power limit Plim than a specific value of the demand power Preq for the internal combustion engine 1.

[0096] In S209, the ECU 10 controls the HMI 8 to notify the user that the power suppression control is in operation. The user receiving the notification can see that the power of the combustion engine 1 is being suppressed. This can reduce any discomfort the user might experience from the reduced emergency operating capabilities of the hybrid vehicle.

[0097] If the cooling determination indicator is ON at S203 (YES at S203), the catalyst temperature Tc decreases continuously as a result of the power suppression control. Accordingly, ECU 10 sets the required power Preq, which was calculated as a normal required power for internal combustion engine 1 at S201 (S204).

[0098] In S205, the ECU 10 controls the HMI 8 to notify the user that the power suppression control has been stopped. This allows the user to understand why the power of the internal combustion engine 1 has increased. This can reduce any discomfort the user might experience from the reactivation of the emergency operating mode.

[0099] As in embodiment 1, if the catalyst temperature Tc exceeds the first threshold TH1 during battery-less operation of the hybrid vehicle 100, the power output of the combustion engine 1 is reduced before the catalyst temperature Tc rises above the first threshold TH1. This reduction in combustion engine power lowers the temperature of the exhaust pipe 21, thereby reducing the radiant heat from the exhaust pipe 21 and preventing a temperature increase in the battery pack 7. Therefore, embodiment 1 protects the battery pack 7 while allowing the hybrid vehicle 100 to continue battery-less operation.

[0100] The “estimated temperature” in the present disclosure is not limited to the catalyst temperature Tc (the bed temperature of the catalyst), but can, for example, be the temperature of the exhaust gas flowing through the exhaust pipe 21. Alternatively, an internal combustion engine temperature that can be estimated from the operating status of the internal combustion engine 1 and the driving force of the hybrid vehicle 100 can be defined as the “estimated temperature”. Furthermore, alternatively, a catalyst temperature Tc that can be estimated from the operating status of the internal combustion engine 1 and the driving force of the hybrid vehicle 100 can be defined as the “estimated temperature”.The ECU 10 can determine the operating status of the internal combustion engine 1 by one of the known methods based on the outputs of the accelerator pedal position sensor 91, the vehicle speed sensor 92, an internal combustion engine speed sensor, an air flow sensor, an intake pressure sensor and the like, none of which are shown.

[0101] In the Fig. In the case described in section 6, the power suppression control is executed during the battery-less operation of the hybrid vehicle 100. During battery-less operation, the hybrid vehicle 100 relies solely on the power of the combustion engine 1 for propulsion, resulting in a high power demand (Preq) for the combustion engine 1. This leads to a greater amount of radiant heat from the exhaust pipe 21 and therefore likely causes a greater temperature increase in the battery pack 7 compared to regular driving. Therefore, during battery-less operation, the power suppression control is particularly effective in preventing a temperature increase in the battery pack 7. [Variation of embodiment 1]

[0102] Exemplary embodiment 1 describes an example in which the degree of suppression of the power of the internal combustion engine 1 depends on the catalyst temperature Tc (see Fig. 3 and Fig. 4) Modification 1 of embodiment 1 describes an example in which the degree of suppression of the power of the internal combustion engine 1 depends not only on the catalyst temperature Tc, but also on the vehicle speed V.

[0103] If the battery pack 7 is located outside the passenger compartment of the hybrid vehicle 100 on its underside (see Fig. 2) The hybrid vehicle 100, traveling at a higher vehicle speed V, causes a stronger airflow against the battery pack 7, resulting in a greater amount of heat radiation from the battery pack 7. This means that the temperature of the battery pack 7 is less likely to rise, even with the radiant heat from the exhaust pipe 21. Consequently, there is less need to suppress the power of the combustion engine 1.

[0104] Fig. Figure 8 is a diagram illustrating the dependence of the power limit Plim on the catalyst temperature and the vehicle speed. Fig. Figure 8 shows the horizontal axis as the vehicle speed V and the vertical axis as the power limit Plim of the internal combustion engine 1. V1 to V3 belong to a speed range of low or medium speeds (e.g. a speed range of less than 60 km / h).

[0105] As in a map MP3 of Fig. As shown in Figure 8, the power limit Plim depends on the catalyst temperature Tc (the power limit Plim decreases with increasing catalyst temperature Tc) when the vehicle speed V is equal to or less than the specified speeds V1 to V3, but does not depend on the vehicle speed V.

[0106] In a high-speed range of vehicle speed V (e.g., a speed range of at least 60 km / h), the power limit Plim depends on both the catalyst temperature Tc and the vehicle speed V. The power limit Plim decreases with increasing catalyst temperature Tc and increases with increasing vehicle speed V.

[0107] Fig. Figure 9 is a flowchart showing the power control of the internal combustion engine 1 in modification 1 of embodiment 1. The overall flowchart of the power control of the internal combustion engine 1 in modification 1 of embodiment 1 is the same as the flowchart described in embodiment 1 (see Figure 9). Fig. 6), and therefore its description will not be repeated. The in Fig. The flowchart shown in Figure 9 differs from the flowchart in embodiment 1 (see Figure 9). Fig. 7) in that the process of S306B is additionally included and that the process of S207 is replaced by the process of S307.

[0108] In relation to Fig. 9 ECU 10 calculates, when the high temperature determination indicator is ON while the cooling determination indicator is OFF (NO for S303), the average value of the catalyst temperature Tc in the last specified period (e.g. one hour) (S306A).

[0109] In S306B, the ECU 10 calculates the average value of the vehicle speed V in the last further specified period (e.g. several minutes).

[0110] In the S307, the ECU 10 determines the power limit Plim, which corresponds to the combination of the average value of the catalyst temperature Tc and the average value of the vehicle speed V, with respect to the map MP3 (see Fig. 8).

[0111] At S308, the ECU 10 compares the preliminary calculated demand power Preq at S301 with the maximum power limit Plim determined at S307 and sets a lower demand power Preq and maximum power limit Plim than the demand power Preq for the internal combustion engine 1.

[0112] As before, in modification 1 of embodiment 1, the power output of the combustion engine 1 during power reduction control is determined not only according to the catalyst temperature Tc, but also according to the vehicle speed V. If the vehicle speed V of the hybrid vehicle 100 is higher, the airflow against the battery pack 7 provides a better cooling effect on the battery pack 7. Accordingly, if the vehicle speed V of the hybrid vehicle 100 is higher than a predetermined speed (one from V1 to V3 in Fig. 8) The degree of suppression of the combustion engine's power 1 can be reduced compared to when the vehicle speed V is lower than the specified speed. Thus, modification 1 of embodiment 1 can provide better battery-free driving performance for the hybrid vehicle 100 than embodiment 1. [Variation 2 of embodiment 1]

[0113] In embodiment 1 and its previously described modification 1, the power limit Plim of the internal combustion engine 1 is reduced during the execution of the power suppression control compared to when the power suppression control is not executed. In modification 2 of embodiment 1, the power suppression control is implemented by changing the required power for the internal combustion engine 1.

[0114] Fig. Figure 10 is a diagram illustrating an example of power suppression control in variation 2 of embodiment 1. With regard to Fig. Figure 10 shows the horizontal axis as the accelerator pedal position Acc and the vertical axis as the demand power Preq for the internal combustion engine 1.

[0115] When power suppression control is not executed, the accelerator pedal position (Acc) and the demand power (Preq) follow a linear relationship, as indicated by the alternating long-short dashed line. However, when power suppression control is executed, in temperature ranges of at least T1, the degree of increase in demand power (Preq) corresponds to an increase in accelerator pedal position (Acc) (= the gradient of the straight line) in the range shown. Fig. The example shown in point 10 is reduced (see the solid line). In other words, when the power suppression control is executed, the requested power Preq for a given accelerator pedal position Acc is reduced compared to when the power suppression control is not executed.

[0116] Thus, the suppression of the combustion engine's power output is not limited by a reduction in the power limit Plim, but can be achieved by a reduction in the demand power Preq. Since the power output of the combustion engine 1 is controlled, as previously described, by a lower demand power Preq and the power limit Plim, the suppression of the combustion engine's power output can also be achieved by a reduction in the demand power Preq. As in embodiment 1 and its modification 1, modification 2 of embodiment 1 can also protect the battery pack 7 from an excessive temperature increase, while allowing the hybrid vehicle 100 to continue driving without battery power.

[0117] Although not shown, in the power suppression control of variation 2 of embodiment 1, the relationship between the accelerator pedal position Acc and the requested power Preq can exhibit a dependence on the vehicle speed, as described in variation 1 of embodiment 1. In particular, for a given accelerator pedal position Acc, a higher vehicle speed V allows for a higher requested power Preq within the range of the requested power Preq without power suppression control. [Example 2]

[0118] Exemplary embodiment 1 describes a case in which the start and stop of the power suppression control depends on the catalyst temperature Tc. However, the use of the catalyst temperature Tc is not essential to determine whether the power suppression control should be executed. Exemplary embodiment 2 describes a case in which the power suppression control is based on the temperature of the battery pack 7.

[0119] Fig. Figure 11 is a block diagram that schematically shows a general configuration of a hybrid vehicle in embodiment 2. With regard to Fig. In embodiment 2, the battery ECU 103 is provided within the battery pack 7. The battery pack 7 contains not only the assembled battery 71, but also a cooling system 72, a terminal box 73, and a battery temperature sensor 74. The other configuration of the hybrid vehicle 200 is the same as that of the hybrid vehicle 100 in embodiment 1, and therefore its detailed description is not repeated.

[0120] The cooling system 72 circulates coolant (not shown) to cool the assembled battery 71. However, the cooling system 72 is not limited to a liquid cooling system, but can be an air cooling system.

[0121] The connection box 73 is a protective box for a connection for coupling or branching a cable harness (not shown) in the battery pack 7.

[0122] The battery temperature sensor 74 detects the temperature of the assembled battery 71 (hereinafter also referred to as "battery temperature Tb") and outputs the result of the detection to the battery ECU 103.

[0123] While the assembled battery 71 is cooled by the cooling system 72, the terminal box 73 and the battery ECU 103 are not cooled by the cooling system 72. Accordingly, the temperature of the assembled battery 71 (battery temperature Tb) detected by the battery temperature sensor 74 is not necessarily the same as the temperature of the terminal box 73 and the battery ECU 103. In some cases, the assembled battery 71 may have a low temperature, while the terminal box 73 and the battery ECU 103 may have a high temperature. There may also be a time lag between the battery temperature Tb and the temperature of the terminal box 73 and the battery ECU 103. Therefore, a high-temperature determination indicator and a low-temperature determination indicator are used, which are determined taking the time lag into account.

[0124] Connection box 73 and battery ECU 103 correspond to the “devices” in the present disclosure. The “devices” may, for example, include a service connector for testing the battery pack 7, a fuse for preventing overcurrent in the assembled battery 71, and a small ECU (satellite ECU) for sensing the voltage of the assembled battery 71, none of which are shown.

[0125] Fig. Figure 12 is a flowchart showing the license plate control of the internal combustion engine 1 in embodiment 2. With reference to Fig. 12 During the battery-free driving of the hybrid vehicle 100 (JA at S401), the ECU 10 receives the battery temperature Tb, which is recorded by the battery temperature sensor 74 (S402).

[0126] If the battery temperature Tb is equal to or greater than a third threshold TH3 (corresponding to the “threshold” in this disclosure) (JA at S403), the ECU 10 advances the process to S404. The processes from S404 to S406 are the same as the corresponding processes in embodiment 1 (see Fig. 6), except that the high-temperature counter X1 and the cooling counter X2 are each replaced by a high-temperature counter X3 and a cooling counter X4, and except that the first reference value REF1 is replaced by a third reference value REF3. The high-temperature counter X3, the cooling counter X4, and the third reference value REF3 can be specified in accordance with the corresponding ratio between the battery temperature Tb and the temperature of the terminal box 73 and the battery ECU 103 (i.e., the presence or absence of the cooling effect by the cooling system 72). As specific means for power suppression control (S406) in embodiment 2, the same means can be used as those in embodiment 1 and its variations 1 and 2 (see Fig. 3, Fig. 4, Fig. 8 or Fig. 10).

[0127] Thereafter, while the high-temperature determination indicator is ON (YES at S407), when the battery temperature Tb becomes equal to or less than a fourth threshold TH4 (corresponding to "another threshold" in the present disclosure) (YES at S409), the ECU 10 advances the process to S410. The processes from S410 to S413 are also identical to the corresponding processes in embodiment 1 (see Fig. 6), except that the second reference value REF2 is replaced by a fourth reference value REF4.

[0128] As previously described in embodiment 2, if the battery temperature Tb exceeds the third threshold TH3 during the battery-less operation of the hybrid vehicle 100, the power output of the combustion engine 1 is reduced before the battery temperature Tb rises above the third threshold TH3. Since the battery pack 7 is neither charged nor discharged during the battery-less operation, any temperature increase of the battery pack 7 during this time is assumed to be due to radiant heat from the exhaust pipe 21. Accordingly, it can be estimated from the temperature of the battery pack 7 whether its temperature has increased due to radiant heat. Suppressing the power output of the combustion engine 1 causes a decrease in the temperature of the exhaust pipe 21, thereby reducing the radiant heat from the exhaust pipe 21 and suppressing a temperature increase of the battery pack 7.Therefore, embodiment 2 can protect the battery pack 7, while the hybrid vehicle 100 is able to continue driving without a battery, as in embodiment 1. [Example 3]

[0129] Exemplary embodiment 1 describes an example with two meters (a high-temperature meter and a cooling meter). Exemplary embodiment 3 describes an example with one meter that is a combination of the two meters (this meter is also referred to as a high-temperature meter). The hybrid vehicle in exemplary embodiment 3 has the same configuration as the hybrid vehicle 100 in exemplary embodiment 1 (see Fig. 1 and Fig. 2), and therefore the detailed description of it will not be repeated. <Zeitdiagramm der Verbrennungsmotorsteuerung>

[0130] Fig. Figure 13 is a timing diagram illustrating the power control of the internal combustion engine 1 in embodiment 3. With regard to Fig. Figure 13 shows the elapsed time on the horizontal axis. The vertical axis shows the vehicle speed V, the catalyst temperature Tc, the high-temperature counter value, the ON / OFF status of the high-temperature detection indicator, and the ON / OFF status of the power suppression request, in that order from top to bottom. In contrast to embodiment 1, embodiment 3 does not have a cooling counter or a cooling detection indicator.

[0131] The hybrid vehicle 100, traveling at a higher vehicle speed V, receives a stronger airflow, which makes it easier to cool the battery pack 7, which is located outside the passenger compartment. Accordingly, in embodiment 3, when the vehicle speed V is equal to or less than a predetermined upper limit speed UL (e.g., UL = 50 km / h), the high-temperature counter increments (i.e., the high-temperature counter value increases). This is because at such a vehicle speed, the battery pack 7 can reach a high temperature. In the embodiment 3, the high-temperature counter increments (i.e., the high-temperature counter value increases) because the battery pack 7 can rise to a high temperature at such a vehicle speed. Fig. In the example shown in 13, it is assumed that the vehicle speed V is constantly below the upper limit speed UL.

[0132] For the catalyst temperature Tc, the first threshold TH1 and the second threshold TH2 are specified. The first threshold TH1 determines whether the catalyst temperature Tc is high. The second threshold TH2 determines whether the catalyst temperature Tc is normal. For the high-temperature counter value (hereinafter referred to as "high-temperature counter value Y"), a first determination value DET1 and a second determination value DET2 are specified. The first determination value DET1 determines whether the catalyst temperature Tc is high. The second determination value DET2 determines whether the catalyst temperature Tc has decreased to normal (i.e., the catalyst has already cooled down).

[0133] In the Fig. In the example shown, hybrid vehicle 100 performs the battery-less driving at time t20. The catalyst temperature Tc at time t20 is a temperature between the first threshold TH1 and the second threshold TH2. The high-temperature counter value Y is 0. The high-temperature detection indicator is OFF. The power suppression request is also OFF.

[0134] The continuous power output of combustion engine 1 causes the catalyst temperature Tc to rise above the first threshold TH1 at time t21. The high-temperature count Y is then increased for the period during which the catalyst temperature Tc remains above the first threshold TH1.

[0135] The high-temperature counter value Y continues to increase until the first determination value DET1 is reached at time t22. In this case, it is likely that the battery pack 7 has reached a high temperature due to radiant heat from the exhaust pipe 21, and therefore the high-temperature determination indicator is switched from OFF to ON. In response, a power reduction request is issued from the hybrid ECU 101 to the internal combustion engine ECU 102. In response to the power reduction request from the hybrid ECU 101, the internal combustion engine ECU 102 reduces the power limit Plim of the internal combustion engine 1.

[0136] Then the power output of combustion engine 1 decreases, causing the catalyst temperature Tc to decrease, so that the catalyst temperature Tc falls below the second threshold TH2 at time t23. The high-temperature count Y is then reduced during the period in which the catalyst temperature Tc is below the second threshold TH2.

[0137] When the high-temperature counter value Y reaches the second determination value DET2 (DET2 < DET1) at time t24, the high-temperature determination indicator is switched from ON to OFF. In response, the output of the power suppression request from the hybrid ECU 101 to the internal combustion engine ECU 102 is stopped (i.e., the power suppression control is deactivated). Afterwards, the high-temperature counter value Y is reset (time t25).

[0138] In the Fig. In the example shown in Figure 13, the period during which the catalyst temperature Tc is above the first threshold TH1, i.e., the period from time t21 to time t22, corresponds to the “first predetermined time” in this disclosure. As described in embodiment 1, if the catalyst temperature Tc is temporarily above the first threshold TH1, the integrated value of the time during which the catalyst temperature Tc is above the first threshold TH1 can be defined as the “first predetermined time” in this disclosure. The period from time t23 to time t24, during which the catalyst temperature Tc is below the second threshold TH2, corresponds to the “second predetermined time” in this disclosure. The “second predetermined time” can also be the integrated value of the time during which the catalyst temperature Tc is below the second threshold TH2. < Flowchart of the internal combustion engine control system>

[0139] Fig. Figure 14 is a flowchart showing the license plate control of the internal combustion engine 1 in embodiment 3. Although not shown for reasons of space, the ECU 10 first determines whether the hybrid vehicle 100 will perform the battery-less driving procedure or not. If the hybrid vehicle 100 does not perform the battery-less driving procedure, the ECU 10 returns the process to the main routine.

[0140] When the hybrid vehicle 100 performs the battery-less driving, the ECU 10 receives the catalyst temperature Tc from the catalyst temperature sensor 22 (S501). The ECU 10 then determines whether the catalyst temperature Tc is equal to or greater than the first threshold TH1 (S502). If the catalyst temperature Tc is equal to or greater than the first threshold TH1 (YES at S504), the ECU 10 proceeds to S503.

[0141] At S503, ECU 10 determines whether the vehicle speed V is equal to or less than the upper limit speed UL. If the vehicle speed V is equal to or less than the upper limit speed UL (YES at S503), the cooling effect on the battery pack 7 due to the airflow is comparatively low. Therefore, ECU 10 proceeds to S504 and increments the high-temperature counter value Y (see time t21 in S503). Fig. 13).

[0142] In S505, ECU 10 determines whether the high-temperature counter value Y is equal to or greater than the first setpoint DET1. The first setpoint DET1 can be determined in the same way as the first reference value.

[0143] If the high-temperature counter value Y is less than the first determination value DET1 (NO at S505), ECU 10 returns the process to the main routine. The high-temperature counter value Y is then incremented for the period during which the catalyst temperature Tc is equal to or greater than the first threshold value TH1. When the high-temperature counter value Y becomes equal to or greater than the first determination value DET1 (YES at S505), ECU 10 switches the high-temperature determination indicator from OFF to ON (S506) (see time t22 in). Fig. 13) In response, the power suppression control is executed.

[0144] If the catalyst temperature Tc obtained at S502 is less than the first threshold TH1 (NO at S502), or if the catalyst temperature Tc is equal to or greater than the first threshold TH1 and the vehicle speed V is greater than the upper limit speed UL (YES at S502 and NO at S503), then ECU 10 advances the process to S507 to determine whether the high-temperature detection indicator is ON or NOT. If the high-temperature detection indicator is OFF (NO at S507), ECU 10 retains the high-temperature counter value Y (S508). The process then returns to the main routine.

[0145] If the high-temperature determination indicator is ON (YES for S507), ECU 10 determines whether the catalyst temperature Tc is equal to or less than the second threshold TH2 (S509). If the catalyst temperature Tc becomes equal to or less than the second threshold TH2 (YES for S509), ECU 10 decrements the high-temperature counter value Y (S510) (see time t23 in S509). Fig. 13).

[0146] If the catalyst temperature Tc is above the second threshold TH2 and the vehicle speed V is greater than the upper limit speed UL (NO for S509 and YES for S513), the ECU 10 reduces the high temperature count Y taking into account the cooling effect on the battery pack 7 due to the airflow (S510).

[0147] In contrast, during the period in which the catalyst temperature Tc is above the second threshold TH2 and the vehicle speed V is equal to or less than the upper limit speed UL, while the power suppression control is executed (NO for S509 and NO for S513), ECU 10 maintains the high-temperature count Y (S514). ECU 10 then returns the process to the main routine.

[0148] In S511, ECU 10 determines whether the high-temperature counter value Y is equal to or less than the second reference value DET2. The second reference value DET2 can be set in the same way as the second reference value REF2.

[0149] If the high-temperature count Y is greater than the second determination value DET2 (NO at S511), ECU 10 returns the process to the main routine. The high-temperature count Y is then further decreased until the second determination value DET2 is reached during the period in which the catalyst temperature Tc is equal to or greater than the second threshold TH2 and the vehicle speed V is equal to or less than the upper limit speed UL. If the high-temperature count Y becomes equal to or less than the second determination value DET2 (YES at S511), ECU 10 switches the high-temperature determination indicator from ON to OFF (S512) (see time t24 in Fig. 13) In response, the power suppression control is stopped (i.e., power suppression is lifted). Afterwards, ECU 10 resets the high-temperature counter value Y, although this is in Fig. 14 is not shown (see time t25 in Fig. 13).

[0150] In this way, if the vehicle speed V is greater than the upper speed limit UL, the ECU 10 maintains the high-temperature count Y. That is, if the vehicle speed V is greater than the upper speed limit UL, the ECU 10 delays the execution of the power suppression control compared to when the vehicle speed V is less than the upper speed limit UL. This can prevent a situation where the power suppression control is unnecessarily initiated when the battery pack 7 has already been cooled by the airflow.

[0151] If the vehicle speed V is greater than the upper speed limit UL, the ECU 10 reduces the high-temperature counter value Y, even if the catalyst temperature Tc is above the second threshold TH2. That is, if the vehicle speed V is greater than the upper speed limit UL, the ECU 10 accelerates the deactivation of the power reduction control compared to when the vehicle speed V is less than the upper speed limit UL. This can prevent a situation where the power reduction control continues unnecessarily when the battery pack 7 has already been cooled by the airflow.

[0152] In the example described above, the upper limiting velocity UL used to determine whether to increase the high-temperature count Y (“first predetermined velocity” in the present disclosure) is equal to the upper limiting velocity UL used to determine whether to decrease the high-temperature count Y (“second predetermined velocity”). However, the “first predetermined velocity” and the “second predetermined velocity” may differ from each other in the present disclosure.

[0153] Fig. Section 14 describes that the high-temperature count Y is maintained when the vehicle speed V is greater than the upper limit speed UL (see S508). However, the high-temperature count Y can be decreased when the vehicle speed V is greater than the upper limit speed UL. By decreasing the high-temperature count Y when the vehicle speed V is greater than the upper limit speed UL, regardless of the catalyst temperature Tc, the output suppression control can be stopped at an early stage, resulting in an early recovery of the driving performance of the hybrid vehicle 100. However, it should be noted that if the protection of the battery pack 7 is important, the high-temperature count Y is preferably maintained even when the vehicle speed V is greater than the upper limit speed UL.

[0154] Fig. Figure 15 is a flowchart showing the power control of the internal combustion engine 1 in embodiment 3. With regard to Fig. 15 The ECU 10 calculates a preliminary value of the requested power Preq for internal combustion engine 1 at S601 based on the accelerator pedal position Acc and the vehicle speed V.

[0155] In S602, ECU 10 determines whether the high-temperature determination indicator is ON or NOT. If the high-temperature determination indicator is OFF (NO in S602), ECU 10 sets the requested power Preq as a requested power for internal combustion engine 1 (S603).

[0156] If the high temperature determination indicator is ON (YES at S602), the ECU 10 reads the catalyst temperature Tc stored in memory and calculates the average value of the catalyst temperature Tc in the last specified period (S604).

[0157] In the S605, the ECU 10 determines the power limit Plim, which corresponds to the average value of the catalyst temperature Tc, by reference to the map MP1 or the map MP2 (see for example Fig. 3 or Fig. 4).

[0158] In S606, the ECU 10 compares the requested power Preq with the power limit Plim and determines a lower value for the requested power Preq and the power limit Plim than the determined value of the requested power Preq for the internal combustion engine 1.

[0159] In S607, the ECU 10 controls the HMI 8 to notify the user that the power suppression control is in operation. The user receiving the notification can see that the power of the combustion engine 1 is being suppressed. This can reduce any discomfort the user might experience from the reduced emergency operating capabilities of the hybrid vehicle.

[0160] As in embodiment 3, only one counter is used instead of two. When the two counters are combined, the same effects as in embodiment 1 can be achieved. That is, if the catalyst temperature Tc exceeds the first threshold TH1 during the battery-less operation of the hybrid vehicle 100, the power output of the combustion engine 1 decreases, thereby reducing the radiant heat from the exhaust pipe 21 and suppressing a temperature increase of the battery pack 7. Therefore, embodiment 3 can protect the battery pack 7 while allowing the hybrid vehicle 100 to continue its battery-less operation.

[0161] In embodiment 3, if the vehicle speed V is equal to or less than the upper limit speed UL, the high-temperature counter Y is increased (S505) or decreased (S511). Thus, the vehicle speed V condition can be added to the condition for determining whether to increase or decrease the high-temperature counter Y, taking into account the cooling effect of the airflow on the battery pack 7. This can prevent the power reduction control from being executed if the battery pack 7 has already been cooled. Therefore, the deterioration in the driving performance of the hybrid vehicle 100 caused by unnecessary execution of the power reduction control can be prevented.

[0162] In embodiment 3, the degree of suppression of the power of the internal combustion engine 1 can depend not only on the catalyst temperature Tc, but also on the vehicle speed V, as in modification 1 of embodiment 1. Although Fig. 15 describes an example in which the power suppression control is carried out by reducing the power limit Plim of the internal combustion engine 1, the power suppression control can also be implemented by changing the required power Preq for the internal combustion engine 1, as described in modification 2 of embodiment 1.

[0163] The Fig. 13, Fig. 14 to Fig.Reference 15 describes an example of power suppression control based on the catalyst temperature Tc. However, in embodiment 3 (i.e., with only one counter), the power suppression control can be implemented based on the temperature of the battery pack 7, as described in embodiment 2.

[0164] While the embodiments of this disclosure have been described, it should be clear that the embodiments disclosed herein are in every respect exemplary and not limiting. The scope of this disclosure is defined by the terms of the associated claims and is intended to include any modification within the meaning and scope that corresponds to the terms of the claims.

Claims

[1] Hybrid vehicle (100) with: an internal combustion engine (1); an exhaust path (2) through which exhaust gas from the internal combustion engine (1) is released; a battery pack (7) located near the exhaust path (2); and a control device (10) which, during an emergency operation of the hybrid vehicle (100), performs a control in which the battery pack (7) is not charged and discharged, and performs a power suppression control in which the power of the internal combustion engine (1) is suppressed, wherein, When the power suppression control is in operation, if the estimated temperature of the battery pack (7) is higher than or equal to a threshold, the control device (10) suppresses the power of the internal combustion engine (1) in comparison to when the estimated temperature is lower than the threshold, while maintaining a state in which the internal combustion engine (1) can deliver power. [2] Hybrid vehicle (100) according to claim 1, further comprising: a drive device (5) that drives a drive motor (32) of the hybrid vehicle (100); and a relay (6) which is electrically connected between the battery pack (7) and the drive device (5), wherein During emergency operation, the control unit (10) opens the relay (6) so that the battery pack (7) is electrically disconnected from the drive device (5). [3] Hybrid vehicle (100) according to claim 1 or 2, wherein the exhaust path (2) has a catalyst (211) for cleaning the exhaust gas, the hybrid vehicle (100) furthermore has a sensor (22) that outputs a temperature of the catalyst (211), and the control unit (10) uses the temperature of the catalyst (211) as the estimated temperature. [4] Hybrid vehicle (100) according to claim 1 or 2, wherein the exhaust path (2) has a catalyst (211) for cleaning the exhaust gas, the hybrid vehicle (100) furthermore has a sensor (91, 92) which outputs an operating state of the internal combustion engine (1), and the control unit (10) estimates a temperature of the catalyst (211) based on the output of the sensor (91, 92) and uses the temperature of the catalyst (211) as the estimated temperature. [5] Hybrid vehicle (100) according to claim 1 or 2, wherein the battery pack (7) comprises a composite battery (71), a cooling system (72) that cools the composite battery (71), and a terminal box (73) that is not cooled by the cooling system (72), and the hybrid vehicle (100) further includes a sensor (74) which outputs a temperature of the composite battery (71) as the estimated temperature. [6] Hybrid vehicle (100) according to any one of claims 1 to 5, wherein the control unit (10) performs the power suppression control when a condition in which the estimated temperature is higher than or equal to the threshold lasts longer than a first predetermined time. [7] Hybrid vehicle (100) according to any one of claims 1 to 6, wherein, when the speed of the hybrid vehicle (100) is higher than a first predetermined speed, the control device (10) delays the start of the execution of the power suppression control compared to when the speed of the hybrid vehicle (100) is equal to or less than the first predetermined speed. [8] Hybrid vehicle (100) according to any one of claims 1 to 7, wherein, if the estimated temperature after a start of the execution of the power suppression control of the internal combustion engine (1) falls below a further threshold value which is smaller than the threshold value, the control device (10) stops the power suppression control. [9] Hybrid vehicle (100) according to claim 8, wherein if a condition in which the estimated temperature is less than the further threshold lasts longer than a second predetermined time after the start of the execution of the power suppression control of the internal combustion engine (1), the control device (10) stops the power suppression control. [10] Hybrid vehicle (100) according to any one of claims 1 to 9, wherein, when the speed of the hybrid vehicle (100) is higher than a second predetermined speed, the control device (10) accelerates a stop of the power suppression control compared to when the speed of the hybrid vehicle (100) is equal to or less than the second predetermined speed. [11] Hybrid vehicle (100) according to any one of claims 1 to 10, wherein the control device (10) increases a degree of suppression of the power of the internal combustion engine (1) with an increase in the estimated temperature. [12] Hybrid vehicle (100) according to claim 11, wherein the control device (10) reduces the degree of suppression of the power of the internal combustion engine (1) with an increase in the vehicle speed of the hybrid vehicle (100). [13] Hybrid vehicle (100) according to any one of claims 1 to 12, further comprising a notification device (8) which notifies a user of the hybrid vehicle (100) that the power suppression control is being executed. [14] Hybrid vehicle (100) according to any one of claims 1 to 13, wherein, when the estimated temperature is higher than or equal to the threshold during power suppression control, the control device (10) reduces a power limit of the internal combustion engine (1) compared to when the estimated temperature is lower than the threshold. [15] Hybrid vehicle (100) according to any one of claims 1 to 13, wherein, in the power suppression control, when the estimated temperature is higher than or equal to the threshold, the control device (10) reduces a requested power for a given accelerator pedal position compared to when the estimated temperature is lower than the threshold. [16] Hybrid vehicle (100) with: an internal combustion engine (1); an exhaust gas path (2) which includes a catalyst (211) for cleaning exhaust gas from the internal combustion engine (1) and through which the cleaned exhaust gas is released; a battery pack (7) located near the exhaust path (2); and a control device (10) which, during an emergency operation of the hybrid vehicle (100), performs a control in which the battery pack (7) is not charged and discharged, and performs a power suppression control in which the power of the internal combustion engine (1) is suppressed, wherein, If, during power suppression control, a condition in which the temperature of the catalyst (211) is greater than or equal to a threshold value lasts for a longer than a predetermined time, the control device (10) suppresses the power of the internal combustion engine (1) to a power limit (Plim) that is greater than zero, in contrast to when the temperature of the catalyst (211) is less than the threshold value, while a condition in which the internal combustion engine (1) can deliver power is maintained, and wherein, during power suppression control, the degree of reduction of the power limit (Plim) is increased with an increase in the temperature of the catalyst (211). [17] Control method for a hybrid vehicle (100) comprising an internal combustion engine (1); an exhaust path (2) through which exhaust gas from the internal combustion engine (1) is released; and a battery pack (7) located near the exhaust path (2), the control method comprising the steps: Capturing (S206) an estimated temperature of the battery pack (7); and During an emergency operation of the hybrid vehicle (100), control of the battery pack (7) to prevent it from being charged and discharged, and, if the estimated temperature is higher than or equal to a threshold, suppression (S208) of the power of the internal combustion engine (1) compared to when the estimated temperature is lower than the threshold, while maintaining a state in which the internal combustion engine (1) can deliver power.

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