Hybrid vehicle

Abstract

To provide a hybrid vehicle that is configured so that when an engine is required to generate electricity under low temperature, electricity generated by a generator can be properly supplied to a battery and a heater to quickly restore a charging / discharging capability and amounts of charge of the battery.SOLUTION: The hybrid vehicle is provided with: an engine 2; a generator 3 installed in combination on the engine 2; a battery 4 that stores electricity generated by the generator 3; a driving motor 6 that drives a wheel 5 with electricity stored in the battery 4; and a heater 7 installed in combination on the battery 4, which is configured so that when the engine 2 is required to generate electricity and when a temperature of the battery 4 is low, electricity generated by the generator 3 is supplied to at least either of the battery 4 and the heater 7, where ratios of electricity supply to the battery 4 and the heater 7 vary on the basis of the temperature of the battery 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to hybrid vehicles. [Background technology]

[0002] When the charge level of the vehicle drive battery installed in vehicles such as hybrid vehicles (HVs) and plug-in hybrid vehicles (PHEVs) that can be externally charged or powered, decreases, a request is made to the generator attached to the engine to generate electricity in order to restore the charge.However, at low temperatures, the battery's charge / discharge capacity decreases, and the generator's power generation may not be able to charge the battery smoothly.

[0003] In order to restore the charge / discharge capacity of the battery at low temperatures, for example, in Patent Document 1 below, a heater 24 is heated by electric power from the battery 21 to heat the battery 21, thereby restoring the charge / discharge capacity of the battery (see paragraphs 0020-0023, FIG. 2, etc. of Patent Document 1). Also, in Patent Document 2 below, a battery heater 8 is operated by electric power generated by a motor MG1 to warm up the battery 6 (see paragraphs 0020-0023, FIG. 1, etc. of Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2022-99418 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-248888 Summary of the Invention [Problem to be solved by the invention]

[0005] In the configuration disclosed in Patent Document 1, sending power from the battery 21, whose charging and discharging capacity has decreased, to the heater 24 places an additional burden on the battery 21, which may cause the system to shut down. Also, in the configuration disclosed in Patent Document 2, the engine is normally driven at low temperatures with reduced catalyst performance, which may result in the system not complying with future exhaust gas regulations such as Euro 7.

[0006] Therefore, the object of this invention is to, when there is a demand for the engine to generate electricity at low temperatures, appropriately supply the electricity generated by the generator to the battery and heater, thereby quickly restoring the battery's charge / discharge capacity and charge amount. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides: The vehicle comprises an engine, a generator connected to the engine, a battery that stores the electric power generated by the generator, a drive motor that drives wheels with the electric power stored in the battery, and a heater connected to the battery, A hybrid vehicle (first configuration) is configured such that when there is a demand for the engine to generate electricity and the temperature of the battery is low, the electricity generated by the generator is supplied to at least one of the battery and the heater, and the ratio of electricity supplied to the battery and the heater is changed based on the temperature of the battery.

[0008] In the first configuration, a configuration (second configuration) can be adopted in which, as the temperature of the battery rises, the rate of power supply to the heater is decreased and the rate of power supply to the battery is increased.

[0009] In the first or second configuration, when the temperature of the catalyst provided in the engine is low and there is an output limit for the engine, a configuration (third configuration) can be used in which the proportion of the power supplied to the heater in the power generated by the generator is higher than when there is no output limit.

[0010] In the first or second configuration, when the temperature of the catalyst provided in the engine is low and there is an output limit for the engine, and when the temperature of the battery is below the charging limit temperature, which is the lowest temperature at which charging is possible, all of the power generated by the generator is supplied to the heater, and when there is no output limit for the engine and the temperature of the battery is below the charging limit temperature, only the power required for the heater from the power generated by the generator can be supplied to the heater (fourth configuration).

[0011] In the first or second configuration, if the temperature of the catalyst provided in the engine is low and there is an output limit for the engine, and the temperature of the battery is higher than the charging limit temperature, which is the lowest temperature at which charging is possible, the power generated by the generator is supplied to both the heater and the battery, and if there is no output limit for the engine and the temperature of the battery is higher than the charging limit temperature, the power generated by the generator can be supplied only to the battery (fifth configuration).

[0012] In the first or second configuration, when the temperature of the battery is equal to or lower than the charging limit temperature, which is the lowest temperature at which charging is possible, the power generated by the generator is supplied to the heater and the drive motor, and when the temperature of the battery is higher than the charging limit temperature, the power generated by the generator is supplied to the heater and the battery (sixth configuration).

[0013] In the first or second configuration, when there is no output limit on the engine and the temperature of the battery is higher than the charging limit temperature but below a heating-unnecessary temperature that requires the battery to be heated, if the required power, which is the sum of the power supplied to the drive motor and the power supplied to the heater, is below the output limit of the engine, the required power is generated by the generator, and if the required power exceeds the output limit of the engine, power is supplied preferentially to the heater, and the surplus power is supplied to the motor (seventh configuration). [Effects of the Invention]

[0014] In this invention, when there is a demand for the engine to generate electricity and the temperature of the battery is low, the electricity generated by the generator is supplied to at least one of the battery and the heater, and the ratio of electricity supplied to the battery and the heater is changed based on the temperature of the battery.Therefore, the electricity generated by the generator can be appropriately supplied to the battery and the heater, and the battery's charge / discharge capacity and charge amount can be quickly restored. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a block diagram showing an embodiment of a hybrid vehicle according to the present invention; [Figure 2] FIG. 10 is a diagram showing the temperature dependency of the charge / discharge capacity of a battery. [Figure 3] 2 is a block diagram showing a case where electric power generated by a generator is supplied to a heater in the hybrid vehicle shown in FIG. 1. FIG. [Figure 4] 2 is a block diagram showing a case in which the electric power generated by the generator is mainly supplied to the battery in the hybrid vehicle shown in FIG. 1. FIG. [Figure 5] 2 is a flowchart showing a flow of battery control of the hybrid vehicle shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] An embodiment of a hybrid vehicle 1 (hereinafter, simply referred to as vehicle 1) according to the present invention will be described with reference to the drawings. As shown in FIG. 1 , vehicle 1 includes an engine 2, a generator 3 connected to engine 2, a battery 4 that stores power generated by generator 3, a drive motor 6 that drives wheels 5 using the power stored in battery 4, and a heater 7 connected to battery 4. This vehicle is a hybrid vehicle 1 (HV) capable of series running, in which the generator 3 is driven by the output of engine 2, and the power generated by generator 3 is charged to battery 4 or directly used to drive drive motor 6 to drive wheels 5. This vehicle 1 may also be capable of EV running, in which the wheels 5 are driven by drive motor 6 while engine 2 is stopped, and parallel running, in which the wheels 5 are driven by both engine 2 and drive motor 6. Furthermore, vehicle 1 includes all electric vehicles, such as plug-in hybrid vehicles (PHEVs) that can be externally charged or externally powered. The electric power generated by the generator 3 is appropriately distributed and supplied to the heater 7, the battery 4, and the drive motor 6 based on the state of the vehicle 1, such as the temperature of the battery 4.

[0017] As shown in Figure 2, the charge / discharge capacity of the battery 4 decreases as the battery temperature TB decreases. As the temperature decreases from room temperature (e.g., 23°C), the charge / discharge capacity gradually decreases, and the decrease becomes more pronounced when the temperature drops below the heating-unnecessary temperature TB1 (e.g., 0°C). When the temperature drops below the charging limit temperature TB0 (e.g., -10°C), it becomes almost impossible to charge the battery 4 with the power generated by the generator 3. To recover this charge / discharge capacity, it is important for the heater 7 to raise the temperature of the battery 4 in the temperature range below the heating-unnecessary temperature TB1 (especially below the charging limit temperature TB0).

[0018] Immediately after starting the engine 2, the catalyst attached to the engine 2 for purifying exhaust gas cannot fully function, so the output of the engine 2 is limited, and sufficient power cannot be generated by the generator 3. Therefore, when the temperature of the battery 2 is low (especially below the charging limit temperature TB0), as shown in FIG. 3, the generator 3 is driven by the engine 2, whose output is limited because the catalyst is heating up, and all of the limited power generated by the generator 3 is supplied to the heater 7, which then heats up the battery 4. Then, once the battery 4 has been heated to a certain degree (to a temperature at least higher than the charging limit temperature TB0) and its charging and discharging capacity is ensured, the power generated by the generator 3 is supplied to the battery 4, as shown in FIG. 4, to charge the battery 4. At this time, some power can also be supplied to the heater 7 to keep the battery 4 warm while charging it.

[0019] Battery control of vehicle 1 under low temperatures will be described in detail with reference to Figure 5. In this battery control, first, the intake air temperature, engine coolant temperature, catalyst temperature, charge amount of battery 4, and battery temperature TB are acquired by the respective sensors (step S1), and then the accelerator opening and vehicle speed operated by the driver are acquired by the respective sensors (step S2). Then, based on the acquired data, it is determined whether or not there is a request for power generation from engine 2 (generator 3) (step S3). In this determination, data on the charge amount of battery 4 is mainly referenced, and it is determined that there is a request for power generation when this charge amount falls below a predetermined value, but the values ​​of the other data acquired in steps S1 and S2 are also taken into consideration as appropriate.

[0020] If it is determined that there is no power generation request (NO side of step S3), the process proceeds to normal control (step S4) and then exits the series of flows. This normal control refers to normal control during vehicle 1 travel, in which the drive motor 6 is driven by power supplied from the battery 4 based on the data acquired in steps S1 and S2. On the other hand, if it is determined that there is a power generation request (YES side of step S3), the battery temperature TB and the heating-unnecessary temperature TB1 are compared (step S5).

[0021] If it is determined that the battery temperature TB is higher than the heating no-go temperature TB1 (No in step S5), it can be determined that the battery 4 has sufficient charge / discharge capacity, and therefore the power generated by the generator 3 is supplied only to the battery 4 to charge the battery 4 (steps S6 and S7), and the flow ends. At this time, the battery 4 is kept warm or heated due to heat generated during charging, so even if the temperature of the battery 4 is low (near the heating no-go temperature TB1), it is not necessary to supply power to the heater 7. On the other hand, if it is determined that the battery temperature TB is equal to or lower than the heating no-go temperature TB1 (Yes in step S5), it can be said that the charge / discharge capacity of the battery 4 is reduced due to the low temperature, and therefore it is necessary to heat the battery 4 with the heater 7. In this case, it is first determined whether the catalyst temperature rise control flag is set (step S8).

[0022] The catalyst temperature rise control flag indicates whether or not to perform control to raise the temperature of the catalyst of engine 2, for example, by retarding the ignition of engine 2. For example, the catalyst temperature or the temperature of the coolant for engine 2 is lower than a predetermined value, and the catalyst temperature rise control flag is set when the catalyst temperature or the temperature of the coolant for engine 2 is lower than a predetermined value. When the catalyst temperature rise control flag is set, the exhaust gas purification capability of the catalyst is low, and increasing the output of engine 2 may result in the exhaust gas not being sufficiently purified. Therefore, it may be necessary to limit the output of engine 2 to comply with exhaust gas regulations. Note that if the output (required amount of power generation) required of engine 2 is small and the exhaust gas can be sufficiently purified even if the catalyst is not fully activated, the catalyst temperature is close to a predetermined value, the catalyst can be expected to have a certain degree of exhaust gas purification capability, and the catalyst will be activated immediately, then output limiting is unnecessary (output limit flag: OFF).

[0023] If it is determined that the catalyst temperature rise control flag is not set (OFF side of step S8), there is no need to limit the output of engine 2 due to exhaust gas regulations. Therefore, engine 2 is driven at the required output to generate electricity with generator 3, and the generated electricity is supplied only to heater 7 to prioritize warming up battery 4 (steps S9, S10), and then the process exits the series of flows. This allows the charge / discharge performance of battery 4 to be quickly restored. On the other hand, if it is determined that the catalyst temperature rise control flag is set (ON side of step S8), it is determined whether the output restriction flag of engine 2 is set (step S11).

[0024] The output limit flag is set when the output required for the engine 2 exceeds the output limit of the engine 2 at that time. If it is determined that the output limit flag is not set (OFF side in step S11), the engine 2 is driven at the required output to generate electricity in the generator 3, and the generated electricity is supplied only to the heater 7 to give priority to warming up the battery 4 (steps S9, S10), and then the process exits the series of flows.

[0025] At low temperatures (TB≦TB1) when there is no output limit on the engine 2 (OFF side in step S11), the amount of power generation required of the engine 2 (generator 3) is the sum of the drive power required to drive the vehicle 1 and the power supplied to the heater 7. However, when the output limit of the engine 2 is less than the sum of the drive power required to drive the vehicle 1 and the power supplied to the heater 7, priority is given to the power supplied to the heater 7, and if there is surplus power, this power is supplied to the drive motor 6 as drive power. Also, at low temperatures (TB≧TB0) when there is no output limit on the engine 2, the power generated by the generator 3 can also be supplied only to the battery 4.

[0026] On the other hand, if it is determined that the output limit flag is set (ON side of step S11), the battery temperature TB is compared with the charge limit temperature TB0 (step S12). If it is determined that the battery temperature TB is higher than the charge limit temperature TB0 (NO side of step S12), the battery 4 has a charge / discharge capability, albeit weak, so the generator 3 generates electricity while the output of the engine 2 is limited, and the generated power is supplied to both the heater 7 and the battery 4 to keep the battery 4 warm while charging (steps S13 and S14), and then the flow ends. At this time, a rise in the temperature of the battery 4 can be expected due to charging the battery 4 with the generated power, but as the temperature of the battery 4 rises, control is performed to reduce the power supply rate to the heater 7 and increase the power supply rate to the battery 4.

[0027] On the other hand, if it is determined that the battery temperature TB is equal to or lower than the charge limit temperature TB0 (Yes in step S12), the charge / discharge capability of the battery 4 is significantly reduced as shown in Fig. 2, so that the generator 3 generates electricity while the output of the engine 2 is limited, and all of the generated electricity is supplied only to the heater 7 to heat up the battery 4 with priority (steps S15, S16), and then the process ends. While the vehicle 1 is running, power can also be supplied to the heater 7 and the drive motor 6.

[0028] In the above-described hybrid vehicle 1, the proportion of the power generated by the generator 3 supplied to the battery 4 and the heater 7 is changed based on the temperature of the battery 4. In particular, as the battery temperature TB rises, the proportion of the power supplied to the heater 7 is controlled to decrease and the proportion of the power supplied to the battery 4 is controlled to increase. This allows the power generated by the generator 3 to be appropriately supplied to the battery 4 and the heater 7, thereby enabling the charge / discharge capacity and charge amount of the battery 4 to be restored more quickly.

[0029] Furthermore, in the above-described hybrid vehicle 1, when the output of the engine 4 is limited at low temperatures, the proportion of the power generated by the generator 3 supplied to the heater 7 is made larger than the proportion of the power supplied to the battery 4 compared to when there is no output limit, so that the limited power generated by the generator 3 is used to raise the temperature of the battery 4, thereby enabling the charge / discharge performance of the battery 4 to be recovered more quickly.

[0030] Furthermore, in the above-described hybrid vehicle 1, when the battery temperature TB is at or below the charging limit temperature TB0 and there is an output limit on the engine 2, all of the electric power generated by the generator 3 is supplied to the heater 7, so that the battery 4 can be efficiently heated with limited electric power. Furthermore, when the battery temperature TB is at or below the charging limit temperature TB0 and there is no output limit on the engine 2, the electric power generated by the generator 3 is supplied to the heater 7 and the surplus electric power is supplied to the drive motor 6. This makes it possible to effectively utilize the generated electric power without wasting it, and to ensure a certain level of driving output for the vehicle 1, even when the battery 4 does not have the charging or discharging capacity at low temperatures.

[0031] Furthermore, in the above-described hybrid vehicle 1, when the battery temperature TB is low and higher than the charging limit temperature TB0, and there is an output limit on the engine 2, the electric power generated by the generator 3 is supplied to both the heater 7 and the battery 4, so that the battery 4 can be charged while being heated (kept warm) with limited electric power. Furthermore, when the battery temperature TB is higher than the charging limit temperature TB0, and there is no output limit on the engine 2, the electric power generated by the generator 3 is supplied only to the battery 4, so that the battery 4 can be charged and kept warm by the heat generated by the charging.

[0032] Furthermore, in the above-described hybrid vehicle 1, when the battery temperature TB is lower than the heating unnecessary temperature TB1 and there is no output limit for the engine 2, the amount of power generation required for the engine 2 (generator 3) is set to the sum of the drive power required to drive the vehicle 1 and the power supplied to the heater 7, so that the vehicle 1 can be driven while heating the battery 4. Furthermore, when the output limit of the engine 2 is less than the sum of the drive power required to drive the vehicle 1 and the power supplied to the heater 7, priority is given to the supply to the heater 7, and the charge / discharge performance of the battery 4 is restored, thereby enabling the vehicle 1 to resume normal driving sooner.

[0033] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. Therefore, the scope of the present invention is defined by the claims rather than the above description, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0034] 1 Hybrid vehicle (vehicle) 2 engines 3. Generator 4 Battery 5 wheels 6 Drive motor 7 Heater TB Battery Temperature TB0 Charging limit temperature TB1 Temperature that does not require heating

Claims

1. The vehicle comprises an engine, a generator connected to the engine, a battery that stores the electric power generated by the generator, a drive motor that drives wheels with the electric power stored in the battery, and a heater connected to the battery, A hybrid vehicle configured such that when there is a request for the engine to generate electricity and the temperature of the battery is low, the electric power generated by the generator is supplied to at least one of the battery and the heater, and the ratio of the electric power supplied to the battery and the heater is changed based on the temperature of the battery.

2. 2. The hybrid vehicle according to claim 1, wherein as the temperature of the battery increases, the rate of power supply to the heater is decreased and the rate of power supply to the battery is increased.

3. 3. The hybrid vehicle according to claim 1, wherein when the temperature of a catalyst provided in the engine is low and there is an output limit on the engine, the proportion of the power supplied to the heater in the power generated by the generator is higher than when there is no output limit.

4. When the temperature of a catalyst provided in the engine is low and there is an output limit of the engine, and when the temperature of the battery is equal to or lower than a charging limit temperature, which is the lowest limit temperature at which charging is possible, all of the electric power generated by the generator is supplied to the heater; 3. The hybrid vehicle according to claim 1, wherein when there is no output limit for the engine and the temperature of the battery is equal to or lower than the charging limit temperature, the amount of electric power generated by the generator that is required for the heater is supplied to the heater.

5. When the temperature of a catalyst provided in the engine is low and there is an output limit of the engine, and when the temperature of the battery is higher than a charge limit temperature, which is the lowest limit temperature at which charging is possible, the electric power generated by the generator is supplied to both the heater and the battery, 3. The hybrid vehicle according to claim 1, wherein when there is no output limit on the engine and the temperature of the battery is higher than the charging limit temperature, the electric power generated by the generator is supplied only to the battery.

6. When the temperature of the battery is equal to or lower than a charging limit temperature, which is the lowest limit temperature at which charging is possible, the electric power generated by the generator is supplied to the heater and the drive motor; 3. The hybrid vehicle according to claim 1, wherein when the temperature of the battery is higher than the charging limit temperature, the electric power generated by the generator is supplied to the heater and the battery.

7. 3. The hybrid vehicle according to claim 1, wherein, when there is no output limit on the engine and the temperature of the battery is higher than a charge limit temperature at which charging is possible but lower than a heating no-go temperature at which the battery needs to be heated, the required power, which is the sum of the power supplied to the drive motor and the power supplied to the heater, is lower than the output limit of the engine, the required power is generated by the generator, and when the required power exceeds the output limit of the engine, power is supplied preferentially to the heater, with the surplus power being supplied to the motor.

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