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Nissan Altima HL32 Hybrid. Manual - part 567

HYBRID CONTROL SYSTEM

HBC-17

< FUNCTION DIAGNOSIS >

HBC

While the front wheels are being driven by the engine via the planetary gears, MG1 is driven by the engine via

the planetary gears, in order to supply the generated electricity to MG2.

Charge The HV Battery

MG1 is rotated by the engine via the planetary gears, in order to charge the HV battery.

During Deceleration Driving

When the vehicle is decelerating, kinetic energy from the front wheels is recovered and converted into electri-

cal energy and used to recharge the HV battery by means of MG2.

SYSTEM OPERATION

General

JMCIA0038GB

JMCIA0039GB

JMCIA0040GB

HBC-18

< FUNCTION DIAGNOSIS >

HYBRID CONTROL SYSTEM

• The Hybrid Vehicle Control System uses two sources of motive force, the engine and MG2, and uses MG1

as a generator. The system optimally combines these forces in accordance with the various driving condi-

tions.

• The hybrid vehicle ECU constantly monitors the SOC condition, the HV battery temperature, the coolant

temperature, and the electrical load condition. If any one of the monitored items fails to satisfy the require-

ments when the READY indicator is ON and the shift lever is in the “P” position, or the vehicle is driven in

reverse, the hybrid vehicle ECU to starts the engine to drive MG1, and then charges the HV battery.

• The Hybrid Vehicle Control System drives the vehicle by optimally combining the operations of the engine,

MG1, and MG2 in accordance with the driving conditions listed below.

The vehicle conditions listed below are examples of typical vehicle driving conditions.

How to Read a Nomographic Chart

• The nomographic chart below gives a visual representation of the planetary gear's rotational direction, rota-

tional speed, and torque balance.

• In the nomographic chart, a straight line is used to represent the relationship between the rotational speeds

of the 3 gears in the power split planetary gear unit. The rotational speed of each gear is indicated by the dis-

tance from the 0 rpm point. Due to the structure of the power split planetary gear unit, the relationship

between the rotational speeds of the 3 gears is always expressed by a straight line.

• The relationship between the gear rotation directions and the torque that acts on each gear is as described

below.

Due to the structure of this hybrid transaxle, the MG2 motive force acts on the ring gear via the motor speed

reduction planetary gear unit. The following illustrations of the power split planetary gear unit operation, rep-

resent the rotational direction, rotational speed and torque condition that act on the ring gear.

READY ON State

Starting with MG2

Driving with MG2 and Engine

During Low Load and Constant-
Speed Cruising

During Full Throttle Acceleration F.

During

Deceleration Driving

During Reverse Driving

JMCIA0041GB

HYBRID CONTROL SYSTEM

HBC-19

< FUNCTION DIAGNOSIS >

HBC

• The following nomographic charts and the illustrations of the power split planetary gear unit operation for

each vehicle driving condition represent one situation as an example.

Condition of power split planetary gear unit

Normal Driving (During Low Load and Constant-speed Cruising)

(B): Starting with MG2

• When the vehicle is started off, the vehicle operates powered only by the MG2.

• When the vehicle starts off under normal conditions, it runs using the motive force of MG2. While driving

under this condition, the rotational speed of the carrier is 0 rpm due to the engine being inactive. In addition,

JMCIA0042GB

Sun Gear (MG1)

Carrier (Engine)

Ring Gear (Output)

Rotational Direction

Torque Condition

JMCIA0043GB

HBC-20

< FUNCTION DIAGNOSIS >

HYBRID CONTROL SYSTEM

since MG1 does not generate any torque, no torque acts on the sun gear. However, the sun gear rotates

freely in the (-) direction balancing the rotating ring gear (Output).

Condition of power split planetary gear unit

(C): Driving with MG2 and Starting Engine

• If the required drive torque increases when driving with MG2 only, MG1 is activated to start the engine.

In addition, if any one of the items monitored by the hybrid vehicle control ECU such as the SOC condition,

the battery temperature, the engine coolant temperature or the electrical load condition deviates from the

specified level, MG1 is activated to start the engine.

• Only when driving with MG2, when the engine starts with MG1, the torque acts on the sun gear (MG1) in the

(+) direction, the carrier (Engine) rotates in the (+) direction in reaction to the torque transmitted by the sun

gear. The ring gear rotates in the (+) direction in reaction to the carrier rotation.

JMCIA0044GB

Sun Gear (MG1)

Carrier (Engine)

Ring Gear (Output)

Rotational Direction

Torque Condition

JMCIA0045GB

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