СИСТЕМА УПРАВЛЕНИЯ ГИБРИДНОЙ СИСТЕМОЙ ОБЩИЕ СВЕДЕНИЯ


  1. OUTLINE


    1. The hybrid system of this hybrid vehicle employs the LEXUS Hybrid Drive under the "Hybrid Synergy Drive" concept*.

      Tech Tips

      *: The "Hybrid Synergy Drive" concept consists of 4 key benefits: fuel efficiency, low emissions, seamless acceleration and silent performance.

    2. Hybrid vehicles use a combination of 2 kinds of power sources, such as engines and electric motors, so as to take advantage of the benefits provided by each power source while compensating for the other's shortcomings. As a result, efficient operation is achieved.

    3. Hybrid vehicles do not need their batteries to be charged externally unlike existing electric-only vehicles. Therefore, special infrastructure is not required to use hybrid vehicles.

    4. Technical development of power units (such as engines or fuel cells) is advancing in various fields. The hybrid system is a flexible system that uses a high-efficiency power unit and electric motors.

    5. Hybrid vehicles have high-voltage electrical circuits. Hybrid vehicles have been developed with consideration given to the protection of drivers and technicians against electrocution.

  2. SPECIFICATION


    1. Motor Generator

      Motor Generator MG1 MG2
      Type Permanent Magnet Motor Permanent Magnet Motor
      Function

      Generates Electricity

      Starts Engine

      Drives Rear Wheels

      Generates Electricity
      Maximum System Voltage DC 650 V DC 650 V
      Maximum Output - 105 kW (141 HP)
      Maximum Torque - 300 N*m (221 ft.*lbf)

    2. Inverter with Converter Assembly

      Item Specifications
      Boost Converter Rated Voltage (Inverter Side) DC 650 V
      Rated Voltage (HV Battery Side) DC 230.4 V
      Hybrid Vehicle Converter Assembly Rated Output Voltage

      DC 11 V to 15 V (Normal Condition)

      DC 11.5 V (Activated at Low Temperatures)
      Maximum Output Current 120 A

    3. Cooling System for Inverter with Converter Assembly

      Item Specifications
      Inverter Water Pump with Motor Assembly Motor Type Brushless
      Discharge Volume 12 L/min (12.7 US qts, 10.6 Imp. qts) or Greater at 65°C (149°F)
      Inverter Coolant Type Toyota Genuine Super Long Life Coolant (SLLC) or Equivalent
      Color Pink
      Capacity

      2.1 Liters (2.2 US qts, 1.8 Imp. qts)*1

      2.3 Liters (2.4 US qts, 2.0 Imp. qts)*2
      Maintenance Intervals First Time 240000 km (150000 miles) or 7 years
      Subsequent Every 80000 km (50000 miles) or 4 years

      • *1: LHD models

      • *2: RHD models

    4. HV Battery

      Item Specifications
      Type Sealed Nickel Metal Hydride (Ni-MH) Battery
      Cell Quantity 192 Cells (6 Cells x 32 Modules)
      Nominal Voltage 230.4 V (1.2 V x 192 Cells)
      Battery Capacity (3HR) 6.5 Ah

    5. Cooling System for HV Battery

      Item Specifications
      Battery Cooling Blower Assembly Motor Type Brushless
      Fan Type Sirocco Fan
      Air Flow Volume

      138 m3/h

  3. MAIN FEATURES


    1. Hybrid vehicles have the following features:

      Features Outline
      Idle Stop (Reduction of Energy Loss) Idling of the engine is automatically stopped (idle stop) to reduce energy loss.
      EV Drive (Efficient Drive Control) This allows the vehicle to be driven using only the electric motor when engine efficiency is low. In addition, electricity is generated when engine efficiency is high. Control is performed to maximize the total efficiency of the vehicle.
      EV Drive Mode If the driver operates the switch and the operating conditions are met, the vehicle can run on only the electric motor.
      Motor Assist An electric motor supplements the engine power when accelerating.
      Regenerative Braking (Energy Regeneration) During deceleration and while depressing the brake pedal, part of the energy that was lost as heat is collected as electrical energy to be reused, for example as motor power.

    2. Generally, there are 3 types of hybrid systems: a series-type hybrid system, a parallel-type hybrid system and a series/parallel-type hybrid system.


      1. Series-type Hybrid System


        1. The motor rotates the wheels, and the engine acts as an electric power source for the motor using a generator.

          A01FPN6E01
          Text in Illustration
          *1 Engine *2 Generator
          *3 Inverter *4 HV Battery
          *5 Motor - -
          A01FPMF Mechanical Power Path A01FPDC Electrical Power Path (DC)
          A01FP93 Electrical Power Path (AC) - -

      2. Parallel-type Hybrid System


        1. Both the engine and the motor directly rotate the wheels. In addition to supplementing the power of the gasoline engine, the electric motor can also serve as a generator to charge the high-voltage battery pack while the vehicle is in motion. Driving the vehicle with the motor only is also possible.

          A01FP5TE01
          Text in Illustration
          *1 Engine *2 Transmission
          *3 HV Battery *4 Inverter
          *5 Motor Generator - -
          A01FPMF Mechanical Power Path A01FPDC Electrical Power Path (DC)
          A01FP93 Electrical Power Path (AC) - -

      3. Series/Parallel Hybrid System


        1. Features of both a series-type hybrid system and a parallel-type hybrid system are combined. The system has 2 motor generators. Electricity can be generated by Motor Generator 1 (MG1) using engine power. The generated electricity is used to charge the HV battery and/or also to power Motor Generator 2 (MG2).

          A01FPQGE01
          Text in Illustration
          *1 Engine *2 Power Split Planetary Gear
          *3 HV Battery *4 Inverter
          *5 Motor Generator 1 (MG1) *6 Motor Generator 2 (MG2)
          A01FPMF Mechanical Power Path A01FPDC Electrical Power Path (DC)
          A01FP93 Electrical Power Path (AC) - -

    3. The mechanism of the LEXUS Hybrid Drive is as follows:


      1. The LEXUS Hybrid Drive mainly consists of an engine, hybrid transmission, inverter with converter assembly and HV battery, and employs a series/parallel-type hybrid system.

        A01FP8PE01
        Text in Illustration
        *1 Engine *2 Hybrid Transmission (Hybrid Vehicle Transmission Assembly)
        *3 Power Split Planetary Gear *4 Motor Speed Reduction Planetary Gear
        *5 Motor Generator 1 (MG1) *6 Motor Generator 2 (MG2)
        *7 Inverter with Converter Assembly *8 Differential
        *9 HV Battery - -
        A01FPMF Mechanical Power Path A01FPDC Electrical Power Path (DC)
        A01FP93 Electrical Power Path (AC) - -

      2. This system optimally performs cooperative control of the 2AR-FSE engine and the high-speed, high-output Motor Generator 1 (MG1) and Motor Generator 2 (MG2) in the L210 hybrid transmission (hybrid vehicle transmission assembly) that provides excellent transmission performance.

      3. Hybrid vehicles have 2 batteries that are used for different purposes. One is the HV battery (nominal voltage of DC 230.4 V) that stores electrical power to drive the vehicle, and the other is the auxiliary battery (nominal voltage of DC 12 V) that supplies electrical power to the electrical components.

      4. Furthermore, this vehicle uses a variable-voltage system consisting of a high-output HV battery with a nominal voltage of DC 230.4 V, a boost converter that boosts the operating voltage of the system to a maximum voltage of DC 650 V and an inverter that converts direct current and alternating current.

      5. Since hybrid vehicles are not equipped with a conventional generator, the voltage from the HV battery is reduced to approximately DC 14 V using the hybrid vehicle converter assembly in order to charge the auxiliary battery.

      6. The HV battery uses sealed Nickel Metal Hydride (Ni-MH) battery cells. This HV battery has a high power density, is lightweight, and offers longevity to match the characteristics of the LEXUS Hybrid Drive. Because charge/discharge control is performed to maintain the HV battery within a constant State Of Charge (SOC) range while the vehicle is operating normally, the HV battery does not require external recharging.

        A01FP33E01
        Text in Illustration
        *1

        Inverter with Converter Assembly


        • Inverter

        • Boost Converter

        • Hybrid Vehicle Converter Assembly

        		 *2 2AR-FSE Engine
        *3

        L210 Hybrid Transmission (Hybrid Vehicle Transmission Assembly)


        • Motor Generator 1 (MG1)

        • Motor Generator 2 (MG2)

        		 *4 Auxiliary Battery (Nominal Voltage of DC 12 V)
        *5 HV Battery (Nominal Voltage of DC 230.4 V) - -

    4. Hybrid vehicles have 2 hybrid related cooling systems, one for cooling the inverter with converter assembly and one for cooling the HV battery.


      1. A cooling system for the inverter with converter assembly that is independent from the engine cooling system is provided to cool the inverter with converter assembly.

      2. This cooling system activates when the power switch is turned on (READY).

        A01FPNJE01
        Text in Illustration
        *1 Inverter Radiator *2 Inverter Water Pump with Motor Assembly
        *3 Inverter with Converter Assembly *4 Inverter Reservoir Tank
        A01FPED Inverter Coolant Flow - -

      3. To ensure the proper performance of the HV battery while it generates heat during the repetitive charge and discharge cycles, a dedicated cooling system is used for the HV battery.

      4. The intake air ducts have been optimally shaped and located to allow a large amount of air to flow smoothly, directing cabin air which is taken in from the rear seat sides toward the battery modules. The low temperature cabin air, less affected by temperature increases caused by sunlight, flows across the battery modules, lowering the temperature of the battery modules and ensuring a high level of cooling efficiency.

      5. The power management control ECU controls the operation of the battery cooling blower assembly. The power management control ECU receives signals from the battery voltage sensor about the HV battery temperature sensors which are built into the HV battery assembly. Then, the power management control ECU controls the battery cooling blower assembly in order to control the battery temperature to an appropriate level.

        A01FPR4E01
        Text in Illustration
        *1 Battery Cooling Blower Assembly *2 HV Battery Module Group
        *a From Cabin - -
        A01FPED Cooling Air Flow - -

  4. PRECAUTION


    1. Hybrid Vehicle High-voltage Safety Measures


      1. High-voltage safety is comprised of 2 points: insulation of high-voltage circuits and cut-off of high-voltage circuits. The hybrid system also detects whether or not a decrease in insulation resistance has occurred between the high-voltage system and body ground.

    2. Insulation of High-voltage Circuits


      1. High-voltage circuits are used between the HV battery, inverter with converter assembly, hybrid transmission (hybrid vehicle transmission assembly) and compressor with motor assembly. These items are connected by a power cable and electrically insulated using cases and covers.

      2. Cables are also shielded using a mesh conductor built into the electrical insulation of the wires. The shielding is grounded to the chassis of the vehicle and the main purpose is to prevent electromagnetic interference.

        A01FPR6E01
        Text in Illustration
        *1 Inverter with Converter Assembly *2 Compressor with Motor Assembly
        *3 Power Cable *4 HV Battery Assembly
        *5 Service Plug Grip *6 L210 Hybrid Transmission (Hybrid Vehicle Transmission Assembly)

    3. Cut-off of High-voltage Circuits


      1. When any of the conditions below occurs, the System Main Relays (SMRs) are automatically shut off by the power management control ECU:


        • Power switch is turned off.

        • Any airbag is deployed.

        • Inverter terminal cover is removed (interlock circuit is opened).

        • Connector cover assembly is removed (interlock circuit is opened).

        • Power cable from the HV battery is removed from the inverter with converter assembly (interlock circuit is opened).

        • Service plug grip handle is raised partway (interlock circuit is opened)*.

        • Specified malfunction occurs.

        Tech Tips

        *: The service plug grip should never be removed when the vehicle is in the READY-ON state.

        A01FPVXE01

      2. A service plug grip is used to cut off the high-voltage circuit manually when servicing the vehicle.

        A01FP6VE01
        Text in Illustration
        *1 Service Plug Grip *2 Insulated Glove

        CAUTION:

        Regarding discharge of the capacitor in the inverter with converter assembly, a charge remains in the high-voltage capacitor in the inverter with converter assembly after the high voltage circuits are shut down. When servicing a hybrid vehicle, after the service plug grip is removed, wait for least 10 minutes to allow the capacitor in the inverter to discharge before beginning work.

    4. HV Battery Handling Precautions


      1. HV battery electrolyte is a highly alkaline potassium hydroxide solution (odorless, transparent and colorless). Careless handling of the HV battery is very dangerous. Handle the HV battery properly in accordance with the procedures below:

        Condition Procedure
        When there is liquid leakage present in the area of the HV battery.

        • Neutralize it with a saturated mixture of boric acid and water.

        • After litmus paper has been used to determine that the mixture is neutral, wipe it up with rags or waste cloth.
        When battery electrolyte gets on skin, eyes, etc.*

        • Flush it with a saturated solution of boric acid and water or with a large amount of water.

        • Remove contaminated clothes at once.
        When a vehicle is scrapped. Remove the HV battery from the vehicle for collection via the specified route.
        When stored. The battery should not be left in a damp or wet location.
        When a vehicle is stored for a long time.

        • Disconnect the auxiliary battery negative terminal.

        • When in storage, the HV battery should be charged every 2 months to prevent HV battery discharge or damage. Using the following procedure, charge the HV battery:


          1. Connect the negative terminal of the auxiliary battery.

          2. Turn the power switch on (IG) for 3 minutes, and do not apply any electrical loads. (This operation is needed to allow the power management control ECU to detect the correct SOC.)

          3. Enter the READY-ON state. After the engine starts, leave it running for 30 minutes to charge the HV battery.

        • If the engine does not start or intermittently stops within 30 minutes, stop the operation at that time. (The HV battery does not need to be charged.)

        CAUTION:

        *: If electrolyte is splashed into eyes, call for help and do not rub eyes. Rinse eyes with a large amount of water and seek medical attention immediately.