ErnestHous

The Lexus is heavier and has a significantly larger gas engine. Given the same EPA test, how what do you think it is that enables the Lexus RX 450h to get better such better city mileage (30 vs 24) versus the Audi Q5 Hybrid?

http://www.fueleconomy.gov/feg/Find....32350&id=33301

Cruiter

Experience in the hybrid technology. They've been at it a lot longer. I may be wrong on this, but I think they have a patent too on the version of Atkinson combustion system they use.

Droid13

Using the term "hybrid" does not mean the systems in two vehicles are essentially the same, especially between different manufacturers. You could hook up an battery operated electric drill to one of your tires and, now you have a hybrid, but that doesn't mean that suddenly you'll get significantly better mileage.

In this particular case, the hybrid specs between the Q5 and the 450h are quite a bit different. The battery output and electric motor power is significantly lower in the Q5, so its a "weaker" hybrid. Even though the Q5 uses more power dense Lithium batteries compared with the NiMH batteries used in the 450H, it's small. The 450H battery still has overall more storage and higher output. Also, the Q5 has one 44hp electric motor. The 450H has 165hp electric motor up front, and 67hp in the back for AWD models.

They are just too different to expect similar results.

cossie1600

Your real world mileage will vary, chances are that you wont match the EPA figures unless you drive slow

ErnestHous

I see. I read the Q5 can drive 2 miles in EV mode at 37MPH. How far does the 450H go in EV mode?

RXSF

450h can only go about 1 - 2 miles but under 25 mph.

Droid13

Not sure the exact spec, in "pure EV" (EV mode is selected and dash light lit up) maybe 1 or 2 miles at 25 mph. However, in practice travelling this kind of distance in pure EV with any NON-plug in hybrid, requires the exact right kind of conditions. Conditions that typically don't happen all that often. A perfectly flat or gentle downhill road, no wind, mild temps (no heater or A/C), not fully loaded with your football player friends and their equipment, etc.

The 25mph limit is somewhat arbitrary though. On Toyota/Lexus hybrids the top "pure" EV speed is a physical constraint imposed by the CVT ratios between the engine, generator and drive motor. At a certain speed, the engine must spin to prevent the generator from over-spinning. However, it is possible to drive under electric power only at greater speeds (I've seen as high as 50mph on occasion). The engine is spinning just to keep the generator rpm in operation range, but no fuel is consumed.

Although I'm not familiar with the Audi system, I suspect it's EV range is very highly dependent on pristine conditions as well. The only hybrids that can run in EV mode with reasonable consistency on a variety of road conditions are of the "plug in" type (GM Volt, Ford Energi's, Prius Plug-in), as they have the whopping huge batteries to handle the load.

Cruiter

I routinely drive mine about 3-4 miles at speeds between 35 and 40mph. Usually there are about 3 bars left so if the road was flat I don't know how far I could go. It DOES REQUIRE a very light touch with the throttle.

ErnestHous

Good explanations. Thanks.