A few words about comparing two ways to get your car more economical and more environment friendly:
As we know, hybrid systems include both - internal combustion engine, and electric one, to perform using possibly smallest amount of petrol fuel. Electrical engine is used to drive the car, using current stored in battery pack, which is recharged, when acceleration pedal is released, and brakes work. At this time electrical engine works "in opposite direction" - as generator, giving energy recovery directed to batteries.
On low and middle speeds, when need for power is relatively low, main source of driving power is electrical engine. When You need full power - both engines work together, giving the car maximum torque.
On every stop (crosslights etc) petrol engine stops, saving fuel and world Start is realised with electric one, working to start the car and additionally (when such need exist) as a starter motor for petrol one.
Now we can list characteristic parameters of hybrid system:
- - Main heart of system is still internal combustion engine as long, as You have to "fill up" the car with any form of energy, and we do not include charging batteries in home socket
- Due to fact, that combustion engine stops and starts very often (especially in city traffic) - it rather must not be diesel, which expects more stabile engine temperature to work properly, and starts usually with using of glowing plugs
- Internal combustion engine works periodically, not all the time
- Internal combustion engine is usually made with most modern (and most "green" technologies), what means often direct gasoline injection - to combustion chamber instead of inlet manifold.
- Hybrid cars are unreasonably expensive due to complicated powering construction
Now let's have a look for LPG conversion:
We use to do it for only one reason: LPG fuel is (and always will be) much more cheap, than gasoline, and cost of conversion isn't high too. Additionally - burning LPG beats burning gasoline from environmental point of view. There's no problem to gain results of 30-40% of maximum EURO-4 amounts of toxic substances in exhaust gases when driving on LPG.
Now my question:
Why the hell somebody wants to compare alternative fueling system for petrol engine, with hybrid system, with heart being in fact the same petrol engine??
From technical point of view, there's no any problem for hybrid system to use LPG fuel for powering combustion engine in it. The only thing to solve is overcoming tech problem of using LPG in direct injected motors, but world-leading LPG companies are very close to offer fully tested solutions of such system.
So - if you really want to be more green, than Joschka Fischer (yers ago...) and Rainbow Warrior (years ago too...) together, you can arrange LPG conversion in your hybrid car to get most modern, most trendy, most expensive, heaviest and unpractical vehicle