There are three basic configurations in hybrid powertrains: series, parallel and split power. Volvo Group's parallel-hybrid drivetrain system I-SAM (Integrated Starter, Alternator Motor) provides the best balance between cost and benefit of the three.
Common hybrid concept
I-SAM integrates a powerful electric motor within a driveline complete with diesel engine and automatic gearbox. The motor also serves as an alternator that provides the onboard battery system with power.
The I-SAM consists of three main components:
- a Permanent Magnet (PM) unit including power converter
- an energy storage system
- a Powertrain Management Unit (PMU)
The PMU has a high diameter to length ratio and is placed between the clutch and an Automatic Mechanical Transmission (AMT).
Allows for downsizing of the diesel engine
The PMU contains the key logics on gear shifting strategies and power split between diesel engine and electric machine. The high power and torque output from the PMU allows for downsizing of the diesel engine.
The PM unit can provide maximum torque from zero speed up to the speed at maximum power. At this speed the diesel engine provides higher power and torque at lower fuel consumption and can therefore complement the propulsion with higher efficiency.