control device

Abstract

Preventing output limitations from the battery. [Solution] The ECU is a control unit for the vehicle. The vehicle includes a battery that stores power for driving, a heating device that raises the temperature of the battery, an MG that generates power to charge the battery, an engine that generates power to drive the MG, and a catalytic converter that purifies the exhaust gas of the engine. The ECU includes a sensor for identifying the state of the battery and a processor. When the engine is requested to start (the battery's SOC is below the charging start value + α1), the processor performs warm-up control to warm up the catalytic converter so that its temperature reaches a predetermined temperature or higher (S114), calculates a predicted value of the battery voltage drop using the state identified by the sensor (S115,6), and controls the heating device to perform warm-up control to raise the temperature of the battery if the predicted value is below a value related to the lower limit voltage at which power cannot be output from the battery during warm-up control (lower limit voltage + α2).

Description

[Technical Field]

[0001] The present disclosure relates to a control device, and particularly to a control device for an electric vehicle. [Background Art]

[0002] Conventionally, there has been a control device for an electric vehicle that acquires the voltage of a driving battery of a vehicle, and executes a second warm-up control for warming up an exhaust purification device while charging the driving battery by increasing the output of an internal combustion engine if the voltage of the driving battery drops during a first warm-up control for operating the internal combustion engine to warm up the exhaust purification device (see, for example, Patent Document 1). [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2022-177419 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] In the electric vehicle disclosed in Patent Document 1, if the exhaust purification device is warmed up when the voltage of the driving battery drops, the internal combustion engine cannot output driving power from the perspective of exhaust gas. For this reason, since it is necessary to travel using electric power from the driving battery, the output voltage of the driving battery falls below the lower limit voltage. As a result, there is a risk that the output from the driving battery may be limited.

[0005] The present disclosure has been made to solve the above-described problem, and an object of the present disclosure is to provide a control device for an electric vehicle that can prevent the output from a battery from being limited. [Means for Solving the Problem]

[0006] The control device relating to this disclosure is a control device for an electric vehicle. The electric vehicle comprises a battery for storing power for the electric vehicle's operation, a heating device for heating the battery, a rotating electric machine for generating power to charge the battery, an engine for generating power to drive the rotating electric machine, and a catalytic converter for purifying the engine's exhaust. The control device comprises a sensor for identifying the state of the battery and a processor. When an engine start request is received, the processor performs warm-up control to warm up the catalytic converter so that its temperature reaches a predetermined temperature or higher, calculates a predicted value for the battery voltage drop using the state identified by the sensor, and controls the heating device to perform warm-up control to heat the battery if the predicted value falls below a value related to the lower voltage limit at which the battery can no longer output power during warm-up control.

[0007] With this configuration, during warm-up control performed when an engine start request is made, if the predicted voltage drop of the battery falls below a value related to the lower voltage limit at which the battery can no longer output power, the battery is heated. This allows for a longer period of time before the battery reaches the lower voltage limit. As a result, it is possible to provide a control device for electric vehicles that can prevent the output from the battery from being limited.

[0008] The catalytic converter may be warmed up by raising the temperature of the engine's exhaust gases. The electric vehicle may further be equipped with a heating device that uses electricity to warm up the catalytic converter.

[0009] The processor may start temperature control after a start request is received. Alternatively, the processor may start temperature control before a start request is received. [Effects of the Invention]

[0010] This disclosure provides a control device for electric vehicles that can prevent the output from the battery from being limited. [Brief explanation of the drawing]

[0011] [Figure 1] This is a block diagram schematically showing the overall configuration of the vehicle according to the embodiment of this disclosure. [Figure 2] This figure shows an example configuration of the engine and engine sensor in this embodiment. [Figure 3] This is a timing chart to explain the challenges of this disclosure. [Figure 4] This flowchart shows the battery charging process flow in this embodiment. [Figure 5] This diagram illustrates the method for calculating the predicted voltage drop of the battery in this embodiment. [Figure 6] This figure illustrates the control results in this embodiment. [Modes for carrying out the invention]

[0012] The embodiments of this disclosure will be described in detail below with reference to the drawings. The same or corresponding parts are denoted by the same reference numerals in the drawings, and their descriptions will not be repeated.

[0013] Figure 1 is a block diagram schematically showing the overall configuration of a vehicle according to an embodiment of this disclosure. Referring to Figure 1, in this embodiment, vehicle 1 is a plug-in hybrid electric vehicle (PHEV) and is configured to enable plug-in charging using power supplied from a charging facility located outside vehicle 1.

[0014] Vehicle 1 comprises an engine 10, an engine sensor 11, a catalytic converter 30, a catalytic converter temperature sensor 21, motor generators (MG) 41 and 42, a power split mechanism 51, a drive shaft 52, a reduction gear 53, drive wheels 54, a power control unit (PCU) 60, an inlet 71, a charging relay 72, a system main relay (SMR) 73, a battery 80, a battery sensor 81, a heating device 82, an ambient temperature sensor 90, and an electronic control unit (ECU) 100.

[0015] The engine 10 outputs driving force for the vehicle 1 to move according to control commands from the ECU 100. In this embodiment, a gasoline engine is used for the engine 10. However, the fuel for the engine 10 is not limited to gasoline, and may be other liquid fuels such as diesel fuel or biofuel (ethanol, etc.). Alternatively, the fuel for the engine 10 may be a gaseous fuel (propane gas, etc.).

[0016] The engine sensor 11 comprehensively describes various sensors that detect the state of the engine 10. The engine 10 and engine sensor 11 will be explained in more detail in Figure 2.

[0017] The catalyst device 30 is provided in an exhaust flow path of the engine 10. The catalyst device 30 includes, for example, a three-way catalytic converter and a filter. The three-way catalytic converter oxidizes unburned components (for example, hydrocarbon (HC) or carbon monoxide (CO)) contained in exhaust gas discharged from the engine 10, and reduces oxidizing components (for example, nitrogen oxides (NOx)). In order for the three-way catalytic converter to exert a predetermined catalytic function, it is required that the temperature thereof is equal to or higher than a predetermined activation temperature. The filter traps PM discharged from the engine 10. In the present embodiment, since the engine 10 is a gasoline engine, GPF (Gasoline Particulate Filter) is employed as the filter. Note that, for example, when the engine 10 is a diesel engine, the filter is DPF (Diesel Particulate Filter).

[0018] A catalyst temperature sensor 21 detects a temperature Tc of the catalyst device 30 (catalyst temperature), and outputs the detection result to an ECU 100.

[0019] An O2 sensor 31 is provided on the upstream side of the catalyst device 30 in the exhaust flow path of the engine 10. The O2 sensor 31 detects an oxygen concentration O1 at a position upstream of the catalyst device 30. Further, an O2 sensor 32 is provided on the downstream side of the catalyst device 30 in the exhaust flow path. The O2 sensor 32 detects an oxygen concentration O2 at a position downstream of the catalyst device 30. Each of the O2 sensors 31 and 32 outputs the detection result thereof to the ECU 100.

[0020] Each of the motor generators 41 and 42 is, for example, a three-phase AC rotating electric machine in which permanent magnets are embedded in a rotor. Both of the motor generators 41 and 42 are driven by a PCU 60.

[0021] The motor generator 41 is connected to the crankshaft of the engine 10 via the power split device 51. The motor generator 41 rotates the crankshaft of the engine 10 using electric power from the battery 80. The motor generator 41 is also capable of generating electric power using the power of the engine 10. The alternating-current power generated by the motor generator 41 is converted into direct-current power by the PCU 60 and charged to the battery 80. Further, the alternating-current power generated by the motor generator 41 may also be supplied to the motor generator 42 in some cases.

[0022] The motor generator 42 rotates the drive shaft 52 using at least one of the electric power from the battery 80 and the electric power generated by the motor generator 41. The motor generator 42 is also capable of generating electric power through regenerative braking. The alternating-current power generated by the motor generator 42 is converted into direct-current power by the PCU 60 and charged to the battery 80.

[0023] Note that it is not essential for the vehicle 1 to include the two motor generators 41 and 42. The vehicle 1 may be a so-called single-motor hybrid vehicle.

[0024] The power split device 51 mechanically connects three elements: the crankshaft of the engine 10, the rotating shaft of the motor generator 41, and the drive shaft 52. The power split device 51 is, for example, a planetary gear mechanism including a sun gear 511, a pinion gear 512, a carrier 513, and a ring gear 514.

[0025] The drive shaft 52 is connected to drive wheels 54 via a reduction gear 53. The reduction gear 53 transmits power from the power split device 51 or the motor generator 42 to the drive wheels 54. Further, the reaction force from the road surface received by the drive wheels 54 is transmitted to the motor generator 42 via the reduction gear 53 and the power split device 51, whereby the motor generator 42 generates electric power during regenerative braking.

[0026] The PCU 60 converts the DC power stored in the battery 80 into AC power and supplies that AC power to the motor generators 41 and 42. The PCU 60 also converts the AC power generated by the motor generators 41 and 42 into DC power and supplies that DC power to the battery 80. The PCU 60 includes, for example, a converter corresponding to motor generator 41, a converter corresponding to motor generator 42, and an inverter.

[0027] The inlet 71 is configured to allow insertion of the charging connector of the charging cable through mechanical connection such as mating. Insertion of the charging connector into the inlet 71 ensures an electrical connection between the vehicle 1 and the charging equipment. Furthermore, the ECU 100 of the vehicle 1 and the control device of the charging equipment can mutually send and receive various information, such as signals and data, through communication compliant with communication standards such as CAN (Controller Area Network).

[0028] The charging relay 72 is electrically connected between the inlet 71 and the PCU 60, and between the inlet 71 and the SMR 73. The SMR 73 is electrically connected between the PCU 60 and the battery 80. The opening and closing of the charging relay 72 and the SMR 73 are controlled according to commands from the ECU 100. When the SMR 73 is closed, power transmission between the PCU 60 and the battery 80 becomes possible. When both the charging relay 72 and the SMR 73 are closed, power transmission between the inlet 71 and the battery 80 becomes possible.

[0029] Battery 80 discharges power to drive the motor generators 41 and 42. Battery 80 is also charged by the power generated by the motor generators 41 and 42. Battery 80 can be a rechargeable battery such as a lithium-ion battery or a nickel-metal hydride battery. Alternatively, a capacitor such as an electric double-layer capacitor may be used instead of battery 80.

[0030] The battery sensor 81 includes a voltage sensor, a current sensor, and a temperature sensor. The voltage sensor detects the voltage Vb of the battery 80. The current sensor detects the current Ib that is input to and output from the battery 80. The temperature sensor detects the temperature Tb of the battery 80 (battery temperature). Each sensor outputs its detection result to the ECU 100. Based on the voltage Vb, current Ib, and battery temperature Tb of the battery 80, the ECU 100 can estimate the State of Charge (SOC) of the battery 80.

[0031] The heating device 82, in accordance with commands from the ECU 100, uses the power of the battery 80 to heat the battery 80, and is composed of, for example, an electric heater.

[0032] The outside temperature sensor 90 detects the temperature (outside air temperature) Ta of the outside air of the vehicle 1 and outputs the detection result to the ECU 100.

[0033] The ECU 100 includes a processor 101 such as a CPU (Central Processing Unit), memory 102 such as ROM (Read Only Memory) and RAM (Random Access Memory), input / output ports, and a counter. The processor 101 executes control programs. Memory 102 stores various control programs and maps. The input / output ports control the transmission and reception of various signals. The counter measures time.

[0034] The ECU 100 controls the equipment so that the vehicle 1 reaches a desired state, based on signals from each sensor and maps and programs stored in memory 102. More specifically, the ECU 100 first determines the required driving force of the vehicle 1 according to the accelerator opening and vehicle speed, and calculates the required power of the engine 10 from that required driving force. The ECU 100 then determines, for example, the engine operating point (combination of engine rotational speed Ne and engine torque Te) that minimizes the fuel consumption of the engine 10, based on the engine 10's required power, so that the system efficiency is optimized for the engine 10's required power. The ECU 100 then generates torque commands to drive the motor generators 41 and 42 and controls the PCU 60 so that the engine 10 operates at that engine operating point, and also controls various parts of the engine 10 (such as the throttle valve 14, injector 17, and spark plug 18, which will be described later).

[0035] The ECU 100 may be configured by dividing it into multiple ECUs, each with its own function. For example, the ECU 100 may include an engine ECU that controls the engine 10, a battery ECU that manages the battery 80, and an integrated ECU that comprehensively controls the entire vehicle 1.

[0036] Figure 2 shows an example configuration of the engine 10 and engine sensor 11 in this embodiment. Referring to Figure 2, the actual engine 10 has multiple cylinders. However, to avoid making the drawing too complicated, only one cylinder is shown as a representative example in Figure 2.

[0037] The engine 10 includes, in addition to the engine sensor 11, an air cleaner 12, an intake duct 13, a throttle valve 14, a surge tank 15, an intake manifold 16, an injector 17, a spark plug 18, and an exhaust manifold 19. The engine sensor 11 includes an airflow meter 111, an intake air temperature sensor 112, a throttle position sensor 113, a coolant temperature sensor 114, a knock sensor 115, a crank position sensor 116, and O2 sensors 31 and 32.

[0038] The air cleaner 12 removes dust and other foreign matter contained in the air (intake) drawn in from outside the vehicle.

[0039] The intake duct 13 connects the air cleaner 12 and the surge tank 15, and also houses the throttle valve 14 inside it.

[0040] The throttle valve 14 is controlled to open and close the intake duct 13 in conjunction with the user pressing the accelerator pedal (not shown).

[0041] The surge tank 15 is installed between the intake duct 13 and the intake manifold 16, providing space to mitigate changes in the flow rate of intake air from outside the vehicle and supply a stable supply of air to each cylinder.

[0042] The intake manifold 16 includes multiple intake branch pipes, each corresponding to one of the multiple cylinders, and connects the surge tank 15 to each cylinder.

[0043] In this example, the injector 17 is located in the combustion chamber of the cylinder and injects fuel into the combustion chamber (direct injection type). The air drawn in from the air cleaner 12 and the fuel injected from the injector 17 mix to create a fuel-air mixture in the combustion chamber.

[0044] The spark plug 18 is located at the top of the combustion chamber and ignites the fuel-air mixture inside the combustion chamber. When the mixture is ignited and burns, the pressure inside the combustion chamber increases, pushing the piston down and causing the crankshaft to rotate. The combustion-induced fuel-air mixture (exhaust gas) is discharged from the combustion chamber when the exhaust valve opens.

[0045] The exhaust manifold 19 is located between each cylinder and the catalytic converter 30. The exhaust gas discharged from the combustion chamber is purified by the catalytic converter 30 and then discharged outside the vehicle through the main muffler (silencer) 22.

[0046] The airflow meter 111 detects the amount of intake air from the air cleaner 12. The intake air temperature sensor 112 detects the temperature of the air drawn into the engine 10 (engine intake air temperature). The throttle opening sensor 113 detects the opening degree of the throttle valve 14 (throttle opening). The coolant temperature sensor 114 is installed in the cooling path of the engine 10's coolant and detects the temperature of the coolant (coolant temperature) Tw. The knock sensor 115 is installed in the cylinder block and detects the magnitude of vibration of the engine 10. The crank position sensor 116 detects the rotational speed of the crankshaft (engine rotational speed) Ne. The O2 sensors 31 and 32 are installed in the exhaust manifold 19 and detect the oxygen concentration in the exhaust gas. Each sensor outputs its detection result to the ECU 100.

[0047] The catalytic converter 30 includes an electric heater 301 that warms up the catalytic converter 30 using power from the battery 80. The relay 302 opens and closes the power circuit between the electric heater 301 and the battery 80 according to a command from the ECU 100.

[0048] Figure 3 is a timing chart illustrating the issues of this disclosure. Referring to Figure 3, the horizontal axis of this graph represents time. The vertical axis, from top to bottom, represents the State of Charge (SOC) of battery 80 (%), the discharge power limit Wout (W) of battery 80, the output from battery 80 (W), whether or not there is a requirement to rapidly warm up the catalytic converter 30, and the voltage of battery 80 (V).

[0049] When the SOC of the battery 80 is 100%, the discharge power limit Wout of the battery 80 is B1 kW, and the output voltage of the battery 80 is C1 V. If EV traveling, in which the vehicle travels only using the electric power of the battery 80, is continued, the SOC of the battery 80 decreases, and the discharge power limit Wout of the battery 80 also decreases. When the SOC reaches A1% and the discharge power limit Wout becomes equal to or lower than B2 kW (B2 < B1), a request to start the engine 10 is issued early even though the vehicle demand for battery output is still less than the discharge power limit. In response to this start request, before the engine 10 is started, the catalyst device is rapidly warmed up by the electric heater 301 for a predetermined period T1 seconds, which is a sufficient period for the catalyst device to reach the activation temperature.

[0050] This rapid warm-up increases the output of the battery 80 and decreases the voltage of the battery 80 from C2 V (C2 < C1). Also, the discharge power limit Wout continues to decrease. However, since the catalyst device 30 is being warmed up, the engine 10 cannot output power, and power generation by the motor generator 41 cannot be performed. For this reason, the battery 80 is not charged by generated power, and the electric power of the battery 80 continues to be output. As a result, the electric power of the battery 80 is output exceeding the discharge power limit Wout. Accordingly, the voltage of the battery 80 continues to drop and reaches the system lower limit voltage C3 V (C3 < C2) (for example, the lower limit voltage required by the inverter of the PCU 60), and the output of the battery 80 is restricted. When this happens, the output of the battery 80 that was originally intended to be output cannot be achieved.

[0051] As described above, if the catalyst device 30 is warmed up when the voltage of the battery 80 drops, the engine 10 cannot output traveling power from the perspective of exhaust gas. For this reason, since it is necessary to travel using electric power from the battery 80, the output voltage of the battery 80 falls below the lower limit voltage. As a result, there is a risk that the output from the battery 80 will be restricted.

[0052] Therefore, when the engine 10 is requested to start, the ECU 100 performs warm-up control to warm up the catalytic converter 30 so that its temperature reaches or exceeds its activation temperature. Using the state identified by the battery sensor 81, the ECU 100 calculates a predicted value for the voltage drop of the battery 80. If the predicted value falls below a value related to the lower limit voltage at which the battery 80 can no longer output power during warm-up control, the ECU 100 controls the heating device 82 to perform heating control to raise the temperature of the battery 80.

[0053] As a result, during warm-up control performed when an engine 10 start request is made, if the predicted voltage drop of the battery 80 falls below a value related to the lower voltage limit at which the battery 80 can no longer output power, the battery 80 is heated up. This allows the battery 80 to reach its lower voltage limit for a longer period of time. Consequently, it is possible to prevent the output from the battery 80 from being limited.

[0054] Figure 4 is a flowchart showing the flow of the battery charging process in this embodiment. Referring to Figure 4, this battery charging process is called and executed by the processor 101 of the ECU 100 at predetermined intervals from higher-level processing.

[0055] The processor 101 of the ECU 100 obtains the State of Charge (SOC) of the battery 80 using the detection result from the battery sensor 81 (step S111). The processor 101 determines whether the obtained SOC is less than or equal to the charging start value + α1 (step S112). α1 is a predetermined value and may be 0 or greater than 0. If it is determined that the SOC is not less than or equal to the charging start value + α1 (NO in step S111), the processor 101 returns the processing to be executed to the higher-level processing of the calling device for this battery charging process.

[0056] If the processor 101 determines that the SOC is less than or equal to the charging start value + α1 (YES in step S111), it determines whether the temperature Tc of the catalyst device 30 from the catalyst temperature sensor 21 is above a predetermined temperature (step S113). The predetermined temperature is a value related to the activation temperature of the catalyst device 30, and may be the activation temperature or a predetermined temperature above the activation temperature.

[0057] If the processor determines that the catalyst temperature Tc is not above a predetermined temperature (NO in step S113), the processor 101 controls the relay 302 of the electric heater 301 to start the rapid warm-up of the catalyst device 30 (step S114).

[0058] Next, the processor 101 uses the detection results from the battery sensor 81 to obtain the temperature Tb, SOC, SOH (State of Health), and cell voltage Vb of the battery 80 (step S115). SOH is the ratio of the current full charge capacity to the full charge capacity of the battery 80 when it was new.

[0059] The processor 101 uses the acquired temperature Tb, SOC, SOH, and cell voltage Vb to calculate a predicted voltage drop due to the rapid warming of the catalyst device 30 (step S116). The method for calculating the predicted voltage drop is predetermined by experiments using the battery 80 or by computer simulation of the battery 80.

[0060] Figure 5 is a diagram illustrating the method for calculating the predicted voltage drop of the battery 80 in this embodiment. Referring to Figure 5, when the temperature of the battery 80 is low, or when the vehicle 1 is running in EV mode, or when the catalytic converter 30 is warming up, and the load on the battery 80 is high, the voltage of the battery 80 drops significantly, in addition to the decrease in OCV which correlates with the decrease in the SOC of the battery 80. This voltage drop increases as the SOH of the battery 80 increases. For example, when the SOH is a low value of D3%, if the cell voltage at the start of warming up the catalytic converter 30 is C2(V), the voltage drop will cause it to fall below the system lower limit voltage C3(V) during warming up, and the battery 80 will no longer be able to output power.

[0061] Thus, the voltage drop of the battery 80 correlates with the cell voltage Vb and SOC of the battery 80 at the start of a high-load state such as the warm-up of the catalytic converter 30, the vehicle output (output of the battery 80), the temperature Tb of the battery 80, and the SOH. Therefore, by identifying this correlation of voltage drop in advance through experimentation or simulation, it is possible to calculate a predicted value of the voltage drop using the identified correlation.

[0062] Returning to Figure 4, the processor 101 of the ECU 100 determines whether the predicted voltage drop calculated in step S116 is less than or equal to the lower limit voltage + α2 (step S117). α2 is a predetermined value and may be 0 or greater than 0. If the processor 101 determines that the predicted value is less than or equal to the lower limit voltage + α2 (YES in step S117), the processor 101 controls the heating device 82 to start heating the battery 80 (step S118).

[0063] If the processor 101 determines that the catalyst temperature Tc is above a predetermined temperature (YES in step S113), the processor 101 controls the engine 10 and the PCU 60 to start the engine 10 if the engine 10 is not operating, and to distribute the output of the engine 10 for charging to the motor generator 41 (step S119).

[0064] If the predicted value is not below the lower limit voltage + α2 (NO in step S117), then after step S118 or after step S119, the processor 101 determines whether the conditions for ending the heating of the battery 80 have been met (step S121). The conditions for ending the heating may be, for example, that the temperature Tb of the battery 80 has reached a predetermined temperature or higher, or that a predetermined period of time has elapsed since the start of heating the battery 80. If the conditions for ending the heating have been met (YES in step S121), the processor 101 controls the heating device 82 to end the heating of the battery 80 (step S122).

[0065] If it is determined that the temperature rise termination condition has not been met (NO in step S121), or after step S122, the processor 101 determines whether the condition for terminating the warm-up of the catalyst device 30 has been met (step S123). The warm-up termination condition may be that a sufficient predetermined period T1 seconds has elapsed from the start of warm-up of the catalyst device 30 until it reaches the activation temperature, or it may be that the temperature of the catalyst device 30 has reached the activation temperature.

[0066] If the warm-up completion condition is met (YES in step S123), the processor 101 controls the relay 302 of the electric heater 301 to terminate the warm-up of the catalytic converter 30 (step S124). Next, the processor 101 starts the engine 10 and controls the engine 10 and PCU 60 to distribute the output of the engine 10 for charging to the motor generator 41 (step S125).

[0067] If it is determined that the warm-up completion condition has not been met (NO in step S123), or after step S125, the processor 101 determines whether the State of Charge (SOC) of the battery 80 has become equal to or greater than the charging completion value while the vehicle 1 is running (step S126). If it is determined that the SOC has become equal to or greater than the charging completion value (YES in step S126), the processor 101 controls the engine 10 and the PCU 60 to terminate the distribution of the output of the charging engine 10 to the motor generator 41 (step S127).

[0068] If it is determined that the SOC is not above the charge termination value (NO in step S126), or after step S127, the processor 101 returns the process to the higher-level process that called this battery charging process.

[0069] Figure 6 is a diagram illustrating the control results in this embodiment. Referring to Figure 6(A), when the engine starting condition is met, such as when the State of Charge (SOC) of the battery 80 becomes less than or equal to the charging start value + α1, the battery 80 begins to heat up. As a result, the temperature of the battery 80 rises, the internal resistance of the battery 80 decreases, and the voltage drop of the battery 80 becomes smaller. Consequently, even when the load on the battery 80 is high, such as when the catalytic converter 30 is warming up, and the SOH is low at D3%, the cell voltage of the battery 80 can be prevented from falling below the system lower limit voltage C3(V).

[0070] [Differentiation] (1) In the embodiment described above, as shown in Figure 2, the catalytic converter 30 includes an electric heater 301, and the electric heater 301 warms up the catalytic converter 30. However, it is not limited to this, and the catalytic converter 30 may not have a heating device such as the electric heater 301, and the catalytic converter 30 may be warmed up by the exhaust gas of the engine 10. In this case, while the catalytic converter 30 is warming up, the ignition timing or exhaust valve timing of the engine 10 may be retarded, or if the engine 10 is a diesel engine, the fuel injection timing may be retarded, or the rotational speed of the engine 10 may be kept at a low rotational speed such as the idling speed. Also, as shown in Figures 4 and 6, if the catalytic converter 30 is equipped with a heating device, the warming up of the catalytic converter 30 is started when the engine starting conditions are met, and the engine 10 is started after the warming up. If the catalytic converter 30 is not equipped with a heating device, the engine 10 is started to warm up the catalytic converter 30 when the engine starting conditions are met.

[0071] (2) In the embodiments described above, as shown in Figures 4 and 6(A), the heating of the battery 80 is started when the load on the battery 80 begins to increase, such as by starting the warm-up of the catalyst device 30. However, the invention is not limited to this, and if the battery 80 is difficult to heat up, the heating of the battery 80 may be started before the load on the battery 80 begins to increase, such as by starting the warm-up of the catalyst device 30, as shown in Figure 6(B). In this way, if the battery 80 is difficult to heat up, the heating time of the battery 80 will be longer and the power consumption for heating will be greater, so it is preferable that the battery 80 has a structure that heats up easily, for example, a structure in which the thermal resistance or heat capacity of the battery 80 is low. This makes it possible to shorten the heating time of the battery 80 and reduce the power consumption for heating, thereby achieving energy savings.

[0072] (3) In the embodiment described above, the catalyst device 30 includes a three-way catalytic converter and a filter, as shown in Figure 1. However, it is not limited to this, and the catalyst device 30 may include a three-way catalytic converter but not a filter, or it may be equipped with a catalyst different from the three-way catalytic converter. Furthermore, the catalyst device 30 may be divided into a part including a three-way catalytic converter and a part including a filter.

[0073] (4) In the embodiment described above, as shown in Figure 1, Vehicle 1 is a PHEV that can be charged externally. However, it is not limited to this, and may be a hybrid electric vehicle (HEV) that cannot be plugged in (externally charged).

[0074] (5) In the embodiment described above, as shown in Figure 1, the engine 10 is configured to generate not only power for power generation but also power for driving. However, it is not limited to this, and the engine 10 may generate power for power generation but not power for driving.

[0075] (6) In the embodiments described above, the motor generators 41 and 42, which are rotating electric machines, are used for both power generation and driving. However, the vehicle 1 is not limited to this, and may be equipped with a rotating electric machine for power generation and a rotating electric machine for driving separately.

[0076] [summary] (I) As shown in Figure 1, the control device (e.g., ECU 100) is the control device for vehicle 1, which is an electric vehicle. As shown in Figures 1 and 2, vehicle 1 includes a battery 80 for storing power for driving vehicle 1, a heating device 82 for heating battery 80, a rotating electric machine (e.g., motor generators 41, 42) for generating power to charge battery 80, an engine 10 for generating power to drive the rotating electric machine, and a catalytic converter 30 for purifying the exhaust of engine 10. As shown in Figure 1, the control device includes a sensor for determining the state of battery 80 and a processor 101. As shown in Figures 4 to 6, when the engine 10 is requested to start (for example, when the State of Charge (SOC) of the battery 80 falls below the charge start value + α1), the processor 101 performs warm-up control to warm up the catalytic converter 30 so that its temperature rises to a predetermined temperature or higher (for example, step S114), calculates a predicted value for the voltage drop of the battery 80 using the state identified by the sensor (for example, steps S115, S116), and controls the heating device to perform heating control to raise the temperature of the battery 80 if the predicted value falls below a value related to the lower limit voltage at which power cannot be output from the battery 80 during warm-up control (for example, lower limit voltage + α2).

[0077] As a result, during warm-up control performed when an engine 10 start request is made, if the predicted voltage drop of the battery 80 falls below a value related to the lower voltage limit at which the battery 80 can no longer output power, the battery 80 is heated up. This allows the battery 80 to reach its lower voltage limit for a longer period of time. Consequently, it is possible to prevent the output from the battery 80 from being limited.

[0078] (II) As shown in Modification (1), the catalytic converter 30 may be warmed up by raising the exhaust temperature of the engine 10.

[0079] (III) As shown in Figures 1 and 2, the vehicle 1 may further be equipped with a heating device (for example, an electric heater 301) that uses electricity to warm up the catalytic converter 30.

[0080] (IV) As shown in Figures 4 and 6(A), the processor 101 may start temperature control after a start request has been received.

[0081] (V) As shown in Figure 6(B) and Modification (2), the processor 101 may be configured to start temperature control before a start request is made.

[0082] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0083] 1 Vehicle, 10 Engine, 11 Engine sensor, 12 Air cleaner, 13 Intake duct, 14 Throttle valve, 15 Surge tank, 16 Intake manifold, 17 Injector, 18 Spark plug, 19 Exhaust manifold, 21 Catalytic converter temperature sensor, 30 Catalytic converter, 31,32 O2 sensor, 41,42 Motor generator, 51 Power split mechanism, 52 Drive shaft, 53 Reducer, 54 Drive wheel, 60 PCU, 71 Inlet, 72 Charging relay, 73 SMR, 80 Battery, 81 Battery sensor, 82 Temperature riser, 90 Ambient temperature sensor, 100 ECU, 101 Processor, 102 Memory, 111 Airflow meter, 112 Intake air temperature sensor, 113 Throttle position sensor, 114 Coolant temperature sensor, 115 Knock sensor, 116 Crank position sensor, 301 electric heater, 302 relay, 511 sun gear, 512 pinion gear, 513 carrier, 514 ring gear.

Claims

1. A control device for electric vehicles, The aforementioned electric vehicle is A battery for storing power for the electric vehicle to run, A heating device for raising the temperature of the aforementioned battery, A rotating electric machine that generates power to charge the aforementioned battery, An engine that generates power to drive the aforementioned rotating electric machine, The system includes a catalytic converter for purifying the exhaust gas of the engine, The control device is A sensor for determining the state of the aforementioned battery, Equipped with a processor, The aforementioned processor, When a request to start the engine is received, warm-up control is performed to warm up the catalytic converter so that its temperature reaches a predetermined temperature or higher. Using the state identified by the sensor, a predicted value of the battery voltage drop is calculated. A control device that controls the heating device to perform heating control to raise the temperature of the battery if the predicted value falls below a value related to the lower limit voltage at which power cannot be output from the battery during the warm-up control.

2. The control device according to claim 1, wherein the catalytic converter is warmed up by raising the exhaust temperature of the engine.

3. The control device according to claim 1, wherein the electric vehicle further comprises a heating device that uses electricity to warm up the catalyst device.

4. The aforementioned processor, The control device according to claim 1, wherein the temperature rise control is started after the start request is made.

5. The aforementioned processor, The control device according to claim 1, which starts the temperature rise control before the aforementioned start request is made.

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