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EP-3943328-B1 - SYSTEMS AND METHODS FOR POWER MANAGEMENT USING ADAPTIVE POWER SPLIT RATIO

EP3943328B1EP 3943328 B1EP3943328 B1EP 3943328B1EP-3943328-B1

Inventors

  • Ramakrishnan, Kesavan
  • HOSHING, VAIDEHI Y.

Dates

Publication Date
20260506
Application Date
20210517

Claims (10)

  1. A method of power management in a hybrid vehicle (100) comprising an engine (101), a motor-generator (106), an aftertreatment system (108) operatively coupled to the engine, a battery (107) operatively coupled to the motor-generator, and a control system (109), the method comprising: obtaining, by the control system, battery temperature and catalyst temperature; determining, by the control system, a) whether the battery temperature is within an optimal battery temperature range and b) whether the catalyst temperature is within an optimal catalyst temperature range; determining, by the control system, a power split ratio based on the determination of a) and b); and controlling, by the control system (109), the engine (101) and the motor-generator (106) based on the determined power split ratio; wherein the method of power management further comprises decreasing, by the control system (109), the power split ratio in response to the control system determining that the catalyst temperature is lower than the optimal catalyst temperature range based on a rate at which the battery temperature or the catalyst temperatures changes; and wherein the method of power management further comprises at least one of: decreasing, by the control system (109), the power split ratio in response to the control system determining that the catalyst temperature is within or lower than the optimal catalyst temperature range and the battery temperature is higher than the optimal battery temperature range; increasing, by the control system, the power split ratio in response to the control system determining that the battery temperature is lower than the optimal battery temperature range and the catalyst temperature is within or higher than the optimal catalyst temperature range; or increasing, by the control system, the power split ratio in response to the control system determining that the catalyst temperature is higher than the optimal catalyst temperature range and the battery temperature is within or lower than the optimal battery temperature range.
  2. The method of claim 1, further comprising: obtaining, by the control system (109), geofencing data (208); determining, by the control system, whether the vehicle is in or approaching a lower-emission zone based on the geofencing data; and setting, by the control system, the power split ratio at 1 in response to determining that the vehicle is in or approaching the lower-emission zone.
  3. The method of any preceding claim, further comprising: obtaining, by the control system (109), lookahead data (208); and determining, by the control system, the power split ratio based on the lookahead data.
  4. The method of claim 3, wherein the lookahead data (208) includes current or forward route condition.
  5. The method of any preceding claim, further comprising: maintaining, by the control system (109), the power split ratio in response to the control system determining that the catalyst temperature and the battery temperature are both within or higher than the respective optimal temperature ranges.
  6. A control system of a hybrid vehicle (100), the hybrid vehicle comprising an engine (101), a motor-generator (106), an aftertreatment system (108) operatively coupled to the engine and a battery (107) operatively coupled to the motor-generator, wherein the control system (109) is configured to: obtain battery temperature and catalyst temperature; determine a) whether the battery temperature is within a predetermined optimal battery temperature range; determine b) whether the catalyst temperature is within a predetermined optimal catalyst temperature range; determine a power split ratio based on the determination of a) and b); and control the engine (101) and the motor-generator (106) based on the determined power split ratio; wherein the control system (109) is further configured to decrease the power split ratio when the catalyst temperature is lower than the optimal catalyst temperature range; decrease the power split ratio based on a rate at which the battery temperature or the catalyst temperatures changes; and wherein the control system (109) is further configured to perform at least one of the following: decrease the power split ratio when the catalyst temperature is within or lower than the optimal catalyst temperature range and the battery temperature is higher than the optimal battery temperature range; increase the power split ratio when the battery temperature is lower than the optimal battery temperature range and the catalyst temperature is within or higher than the optimal catalyst temperature range; increase the power split ratio when the catalyst temperature is higher than the optimal catalyst temperature range and the battery temperature is within or lower than the optimal battery temperature range.
  7. A hybrid vehicle system comprising: an engine (101), a motor-generator (106), an aftertreatment system (108) operatively coupled to the engine, a battery (107) operatively coupled to the motor-generator, and the control system of claim 6.
  8. The hybrid vehicle system of claim 7, further comprising a telematics unit (111), wherein the control system is further configured to: obtain geofencing data (208) from the telematics unit; determine whether the vehicle is in or approaching a lower-emission zone based on the geofencing data; and set the power split ratio at 1 when the vehicle is in or approaching the lower-emission zone.
  9. The hybrid vehicle system of claim 7 or 8, further comprising a telematics unit (111), wherein the control system (109) is further configured to: obtain lookahead data (208) from the telematics unit; and determine the power split ratio based on the lookahead data.
  10. The hybrid vehicle system of claim 9, wherein the lookahead data (208) includes current or forward route condition.

Description

FIELD OF THE DISCLOSURE The present invention relates generally to vehicles, especially to power management of hybrid vehicles having an electrical motor and a fuel-powered engine. BACKGROUND A hybrid power generation system may include a hybrid control system, a battery, a motor-generator, and an engine (e.g., a diesel engine). A control system of the hybrid vehicle may direct the battery and/or the engine / motor-generator to provide power to move the vehicle. Additionally, in some instances, the engine / motor-generator may also provide power to recharge the battery. For instance, currently, when a state of charge (SOC) for the battery is below a minimum charging threshold, the control system may direct the engine / motor-generator to recharge the battery up to a charging threshold. As such, power management strategies of the hybrid vehicle may incorporate using the motor-generator and the engine effectively for more options than when only one or the other is implemented. However, existing power management strategies focus on meeting emission and fuel economy targets without considering the states of the individual components. For example, to reduce the emission, the motor-generator may be used more frequently than the engine, but the battery's performance is derated when the operating temperatures are above the pre-set thresholds. Also, over time, the battery may degrade. For example, initially, a battery may last eight hours under normal usage. But, over time and due to the battery's degradation, the battery might last only four hours. Additionally, and/or alternatively, severe conditions, such as weather-related conditions and/or natural disasters, may cause more usage of a battery than normal. Furthermore, the life of the aftertreatment catalyst may be affected adversely due to constant operation at very high temperatures. As such, it may be desirable to develop a hybrid control system that can effectively use the hybrid components (both the engine and the motor-generator) to eliminate or alleviate one or more operational disadvantages described above. GB2487733A describes a hybrid electric vehicle featuring a first and one or more further actuators, eg an internal combustion engine and an electric motor, each operable to deliver a torque to a driveline. The hybrid vehicle further comprises a controller which determines the required torque split between the actuators. The controller may override the control output of the torque split in response to the value of one or more vehicle parameters. SUMMARY According to one aspect of the present invention there is provided a method of power management in a hybrid vehicle as defined in claim 1. According to another aspect of the present invention there is provided a control system as defined in claim 6. Preferred features of the invention are recited in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: FIG. 1 is a schematic diagram of a hybrid vehicle according to some embodiments.FIG. 2 is a schematic diagram of a control system used in the hybrid vehicle of FIG. 1 according to some embodiments.FIG. 3 is a graph comparing SOC target level and actual SOC profile in a drive cycle implementing a blended mode strategy according to some embodiments.FIG. 4 is a flow chart of a method of determining power split ratio (PSR) values according to some embodiments.FIG. 5 is a partial schematic diagram of a hybrid vehicle according to some embodiments.FIG. 6 is a graph of battery SOC trajectories in a baseline method as known in the art, which incorporates charge-depleting and charge-sustaining modes. Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner. While the present invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the present invention to the particular embodiments described. On the contrary, the present invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the present invention as defined by the appended claims. DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the present invention is practiced. These embodiments