Portable range extender
Making a comparison between a classic vehicle and a pure electric vehicle it can observe some big disadvantages of the electric vehicle such as the limited autonomy, the recharging time and the high cost.
Adding a range extender to the electric vehicle (green color in the diagram) can obtain an improved autonomy, reduced charge time but also relatively low cost of the vehicle doe to the small battery package. That seems to be the best compromise to obtain the customer acceptance.
After AVL [Assessment report on possible options for hybrid gas/electricity light-duty vehicles], there are several demands that have to be fulfilled by a range extender to be attractive on the market. The most important are listed below without prioritization.
- Low system cost
- Low weight
- Low vibration
- Easy to integrate
- Emission compliant (incl. CO2)
- Legally compliant (crash, safety, EMC, noise, etc)
- Availability of fuels
The HOPE concept, in the configuration for hybrid vehicle or for electric vehicle with extended range, can have an ultra-compact structure even in association with a starter-alternator. This auxiliary unit, having high power density, is very simple and cheap because the engine is simple and cheap. The total weight can be very low and consequently this power unit can be transported by people and moved from the vehicle when is not need it. This represents the concept of the portable range extender.
HOPE range extender package
A 30 kW power unit (having a starter-alternator) designed for hybrid or for electric vehicle with extended range can have a weight of around 24 kg. The engine is fully balanced even with only two pistons and consequently the NVH level is reduced including to high RPM.
The proposed concept satisfies completely the requirements for a range extender.
Further development: An ultra low cost variant of this range extender (or auxiliary power unit for other applications) is also available. This represents the simplest balanced range extender having only few elements and offering an extreme durability.