HYBRID CONTROL SYSTEM

Control List

1. The hybrid system consists of the controls listed below.

   Control	Outline
   Hybrid Vehicle Control	The hybrid vehicle control ECU assembly calculates the target motive force based on the shift lever position sensor, the degree to which the accelerator pedal is depressed, and the vehicle speed. The hybrid vehicle control ECU assembly performs control in order to create the target motive force by optimally combining MG1, MG2, MGR*1 and the engine. The hybrid vehicle control ECU assembly calculates the engine motive force based on the target motive force, which has been calculated based on the requirements of the driver and vehicle conditions. In order to create this motive force, the hybrid vehicle control ECU assembly transmits signals to the ECM. The hybrid vehicle control ECU assembly monitors the conditions of the HV battery and battery cooling blower assemblies to perform control using feedback to keep the HV battery at a predetermined temperature.
   	System Monitoring Control	The hybrid vehicle control ECU assembly monitors the State Of Charge (SOC) of the HV battery and the temperature of the HV battery, MG1, MG2 and MGR*1, in order to optimally control these items.
   	Shut Down Control	When the shift lever is in N, the hybrid vehicle control ECU assembly performs shut down control to stop driving MG1, MG2 and MGR*1.
   	System Main Relay (SMR) Control	To ensure that it is possible to connect and disconnect the high voltage circuits reliably, the hybrid vehicle control ECU assembly controls the 3 System Main Relays (SMRs) to connect and disconnect the high voltage circuits from the HV battery. The hybrid vehicle control ECU assembly also uses the timing of the operation of the SMRs to monitor the operation of the relay contacts.
   	State Of Charge (SOC) Control	The hybrid vehicle control ECU assembly calculates the SOC by estimating the charging and discharging amperage of the HV battery. The hybrid vehicle control ECU assembly constantly performs charge/discharge control based on the calculated SOC in order to maintain the SOC within its target range.
   	Inverter Coolant Cooling Control	In order to cool the inverter with converter assembly, MG1 and MG2, the hybrid vehicle control ECU assembly regulates the inverter water pump with motor assembly in accordance with the signals from the temperature sensor for the inverter coolant.
   	HV Battery Cooling Control	In order to maintain the HV battery temperature at the optimal level, the hybrid vehicle control ECU assembly regulates the battery cooling blower assemblies in accordance with the signals from the HV battery temperature sensor.
   	Auxiliary Battery Charging Control	The hybrid vehicle control ECU assembly uses the auxiliary battery temperature sensor (thermistor assembly) to monitor the temperature of the auxiliary battery. The hybrid vehicle control ECU assembly performs charge control based on the temperature information from the auxiliary battery.
   ECM Control	The ECM receives the target engine speed and required engine motive force sent from the hybrid vehicle control ECU assembly, and controls the Electronic Throttle Control System-intelligent (ETCS-i), fuel injection volume, ignition timing and Variable Valve Timing-intelligent (VVT-i) system.
   Motor Generator Main Control	MG1, which is driven by the engine, generates high voltage (alternating current) in order to operate MG2 and MGR*1, and charge the HV battery via the inverter. Also, MG1 functions as a starter to start the engine. MG2, which is driven by electrical power from MG1 and/or the HV battery, generates motive force for the front wheels. MGR, which is driven by the electrical power from MG1 and/or the HV battery, generates motive force for the rear wheels.*1 MG2 generates electricity to charge the HV battery (regenerative braking control) during braking or when the accelerator pedal is not being depressed. Rotation sensors detect the speed and the position of MG1, MG2 and MGR*1 for use by the hybrid vehicle control ECU. Rotation sensor signals are transmitted to the hybrid vehicle control ECU assembly via the Motor Generator ECU (MG ECU). Temperature sensors mounted in MG1, MG2 and MGR*1 detect the temperature for use by the hybrid vehicle control ECU assembly.
   Boost Converter Control	The boost converter boosts the HV battery voltage from a nominal voltage of DC 288 V to a maximum voltage of DC 650 V, in accordance with the signals provided by the hybrid vehicle control ECU assembly via the MG ECU. The inverter converts the alternating current generated by MG1 or MG2 into a direct current. The boost converter reduces the generated voltage from up to 650 V to approximately DC 288 V for the HV battery in accordance with the signals provided by the hybrid vehicle control ECU assembly via the MG ECU.
   Inverter Control	The inverter converts direct current from the HV battery into an alternating current for MG1, MG2 and MGR*1, or vice versa, in accordance with the signals provided by the hybrid vehicle control ECU assembly via the MG ECU. In addition, the inverter is used to transfer power from MG1 to MG2. Via the MG ECU, the hybrid vehicle control ECU assembly sends signals to the power transistors on the Intelligent Power Modules (IPMs) in the inverter for switching the U, V and W phases of MG1, MG2 and MGR*1, in order to drive MG1, MG2 and MGR*1. The hybrid vehicle control ECU assembly shuts down the inverter when the ECU receives an overheat, overcurrent or fault voltage signal from the inverter via the MG ECU.
   Hybrid Vehicle Converter Assembly Control	Reduces the voltage from DC 288 V (nominal) to DC 14 V (nominal) in order to supply electricity to body electrical components, as well as to recharge the auxiliary battery (DC 12 V). This converter keeps the auxiliary battery at a constant voltage.
   E-Four System Control*1	E-Four system control calculates the torque distribution ratio of front and rear wheels based on various signals from each sensor sent by the hybrid vehicle control ECU assembly using its built-in AWD control.
   Battery Voltage Sensor Control	The battery voltage sensor monitors the insulation of the high voltage electrical system for leakage. In addition, the sensor converts the feedback signals of the battery cooling blower assemblies and the conditions of the HV battery (which are needed by the hybrid vehicle control ECU assembly to perform SOC control and HV battery cooling control) into digital signals, and transmits the signals to the hybrid vehicle control ECU assembly.
   Shift Control	The hybrid vehicle control ECU assembly the shift position (P, R, N, D or S) in accordance with the signals provided by the shift lever position sensor and the transmission control switch, and controls MG1, MG2, MGR*1 and the engine to match the selected shift position.
   Skid Control ECU Control	Regenerative Braking Cooperative Control	During braking, the skid control ECU assembly calculates the required regenerative braking force and transmits a signal to the hybrid vehicle control ECU assembly. Upon receiving this signal, the hybrid vehicle control ECU assembly transmits an actual regenerative braking control value to the skid control ECU assembly. Based on this result, the skid control ECU assembly calculates and executes the required hydraulic pressure braking force.
   	TRC/VSC Cooperative Control	The skid control ECU assembly transmits a request to the hybrid vehicle control ECU assembly to limit motive force while the TRC or VSC is operating. The hybrid vehicle control ECU assembly controls the engine, MG1, MG2 and MGR*1 in accordance with the present driving conditions in order to suppress the motive force.
   During Collision Control	During a collision, if the hybrid vehicle control ECU assembly receives an airbag deployment signal from the airbag ECU assembly, the ECU turns the SMRs off in order to shut off the high voltage power supplied to the hybrid system by the HV battery.
   EV Mode Control	When the EV mode switch is manually operated by the driver, the hybrid vehicle control ECU assembly operates to run the vehicle using only MG2 if the required conditions are satisfied.
   Drive Mode Select Control	Optimally controls the outputs of MG1, MG2 and MGR*1 and the engine in accordance with the following drive modes: NORMAL, ECO, SPORT*2 and SPORT S/S+*3 modes.
   Brake Override System	The driving torque is restricted when both the accelerator and brake pedals are depressed. (For the Activation Conditions and Inspection Method, refer to the Repair Manual.)
   Drive Start Control System	Even if the driver is in a hurry and abnormal accelerator pedal and shift operations are performed, vehicle speed and acceleration are restricted to improve the sense of security felt by the driver.

   
   

   • *1: AWD models

   • *2: Models without AVS

   • *3: Models with AVS

Hybrid System Activation (READY-on State)

1. The hybrid system is activated by pressing the power switch while the brake pedal is being depressed. At this time, the READY indicator light flashes until the system check is completed. When the READY indicator light turns on, the hybrid system has started and the vehicle is ready to drive.

2. Even if the driver turns the power switch on (READY), sometimes the hybrid vehicle control ECU assembly will not start the engine. The engine will only start if conditions such as engine coolant temperature, SOC, HV battery temperature and electrical load require an engine start.

3. After driving, when the driver stops the vehicle and moves the shift lever to P, the hybrid vehicle control ECU assembly allows the engine to continue running. The engine will stop after the SOC, HV battery temperature and electrical load reach a specified level.

   Note

   When the hybrid system is unavoidably required to be stopped while driving, the system can be forced to stop by pressing and holding the power switch for approximately 2 seconds or more or pushing the power switch 3 times or more in a row. At this time, the power source will change to on (ACC). The reafter, the hybrid system can be restarted by pressing the power switch with the shift lever in N (the system may not restart due to the vehicle conditions).

EV Drive Mode

1. When all required conditions, some of which are listed below, are satisfied, EV drive mode can be used.

   Operating Condition

   The hybrid system temperature is not high. (The hybrid system temperature will be high when the outside air temperature is high or after the vehicle has traveled up a hill or at high speeds.) The hybrid system temperature is not low. (The hybrid system temperature will be low after the vehicle has been left for a long time when the outside air temperature is low.) The SOC is approximately 50% or higher. The vehicle speed is approximately 50 km/h (25 mph) or less. (Engine coolant temperature: 70°C (158°F) ormore) The accelerator pedal depression amount is a certain level or below. The defroster is off. The cruise control system is not operating.