Hybrid Synergy Drive©
Hybrid Synergy Drive is a full Hybrid - no half measures. It is the most dynamic and efficient Hybrid offering excellent driving performance and outstanding efficiency by combining two power sources - a 1.8 litre petrol engine and 2 electric motors. As a full Hybrid it is capable of operating in petrol or electric modes alone, as well as a combination of both.
Power Split Device (PSD) and Electronically Controlled CVT (E-CVT)
How does it work?
The core of an HSD powertrain is its Power Split Device. For the driver, this system provides a transmission that feels mostly like a CVT. The engine remains always at the most fuel-efficient rpm for the required power, like in a real CVT. That is also where the comparison ends. In HSD, the Power Split Device masters the flow of power from the engine and electric motor to the wheels and generator. Its real strength is its ability to direct power flows in many directions:
- Electric motor -> wheels (EV)
- Electric motor + Atkinson engine -> wheels (Full acceleration)
- Atkinson engine -> wheels & generator (Drive and battery charge)
- Electric motor + Atkinson engine -> wheels & generator (most normal driving conditions)
- Electric motor -> wheels
- Generator -> starting the Atkinson engine
- Wheels -> electric motor (braking, coasting, battery recharge)
- Wheels -> electric motor + Atkinson engine (B-mode).
This will induce engine braking, to be used on long downhills. Through this intelligent power flow management it is effectively the Power Split Device that makes the series: series/parallel full hybrid HSD possible.
HSD Components Electronic Control Unit (ECU)
The ECU could be said to be the Hybrid system’s brain. It constantly monitors and controls the petrol engine, generator, electric motors and battery
It receives braking data from the car’s control network and reads driver intentions from the accelerator and gear shift position
1 Nickel Metal Hydride Battery
- This battery provides the world’s top input/output to weight ratio
- It is lightweight and has a long life. The system maintains the battery charge at a constant level, avoiding excessive battery draining/ recharging.
- It does not require recharging from an outside power source
- Proven track record and reliable
2 Petrol Engine
- An energy-efficient, 1.8 litre petrol unit that works on the Atkinson cycle rather than the Otto cycle of almost every other petrol engine in present day use
- Maximum power output: 73 kW (99 hp) @ 5,200 rpm
- Maximum torque: 142 Nm @ 4,000 rpm
3 Electric Motor (Parallel function)
- This synchronous AC motor propels the car alone and in combination with the petrol engine when required.
- Maximum output: 60 kW (80 hp) @ 1200 - 1540 rpm
- Maximum torque: 207 Nm @ 0 - 1200 rpm
4 Starter/Generator (Series function)
- At its most fuel efficient operating conditions, the Atkinson engine may be producing more energy than required. This energy can be stored by the generator in the battery for later use.
- Acts as a starter motor and as a generator to recharge the battery
- Its high speed axial rotation has made it possible to produce substantial electrical power while the car is running in the midspeed range
5 Regenerative Braking System
- Re-uses the kinetic energy to generate electricity rather than dispersing it as heat as in a conventional braking system
- For instance, in stop-start city traffic the system uses regenerative braking with the wheels effectively driving the electric motor in generator mode
6 Power Control Unit
Has three functions:
The inverter converts DC supplied by the battery to AC to turn the electric motor. Conversely, it converts AC generated by the electric motor and the generator into DC to recharge the battery
The voltage-boosting converter increases the normal 201 Volt DC supply voltage to a maximum of 650 Volt to feed the electric motors and the generator as required.
The DC/DC converter steps down the high voltage from the HSD battery to the normal 12 volts used by ancillary systems and electronic devices.
Intelligent use of engine and electric motor delivers outstanding fuel efficiency comparable to cars one class smaller in engine displacement/ body size, but at the same time with power comparable to cars one class larger. HSD delivers the highest level of fuel efficiency for cars of the same size engine displacement.
With HSD’s exceptionally low fuel consumption, CO2 and other exhaust emissions are significantly lowered; it complies with the world’s most stringent exhaust gas regulations including EURO V and AT-PZEV (Advanced Technology Partial Zero Emissions Vehicle).
HSD delivers driving performance with seamless acceleration, powerful take off and overtaking acceleration – new driving sensations which can only be experienced with a full hybrid car.
The quiet running of electric motors powered by HSD is of practical benefit – for instance, early in the morning or late at night through a residential area, or moving quietly in and out of a parking garage, where sound is often amplified.