ErnestHouse

The Lexus RX 450h hybrid won't go into EV mode until the engine warms up. So for short trips around town, it's electric side is of little benefit.

Is the Q5 the same? i.e. the ICE has to warm up before EV mode is available?

MP4.2+6.0

on the Lexus, isn't the AWD basically only because they are using electric motors in the rear, plus the front more typical Toyota hybrid FWD packaging. If so, that would make the AWD feature pretty useless in many getting going in the morning or end of day/night conditions--kind of like an extreme case of 10 minute glow plugs of some bygone diesel era.

Nothing I've seen about the Audi hybrid approach says anything special relative to the cold start scenario. They have the hybrid SSP from a while back with some backgrounder too. It might not be EV functional, but the drive system being basic quattro still means it should be functioning as regular AWD. They do talk about the cooling circuits for high operating temps though. The high temp cooling sounds a bit of the stereotype German design complexity, perhaps that is until the 787 lithium battery questions of late.

Q5White13

If I consider to buy a hybrid, probably it's because of the better city fuel economy of short trips. If EV mode doesn't kick in when the engine is cold, I think it's a total nonsense.
If it's true, I won't consider to buy a hybrid at all. The diesel is the way to go.

ErnestHouse

Exactly... the RX 450h is a non-starter in my book for that very reason. I hope the Q5 doesn't have that flaw.

MP4.2+6.0

If car is in pure EV mode at start up then engine wouldn't have run and converter(s) by definition would not have lit off to reduce emissions. They may run motor initially as part of emissions strategy so the converter system is up to operating temp's and ready to go. On a conventional motor, including the last three Audis I have owned with EFI, on cold start the car kicks up the idle and delays shifting out of first as part of the emissions strategy to get the converters heated up more quickly. Without them up to operating temp if the car cycles between EV and gas in short intervals car could emit a lot of unprocessed exhaust during the sporadic gas cycle. A big percentage of emissions now occur only before that converter light off.

ErnestHouse

@MP4.2+6.0: Thanks for that explanation. I think you are saying the Audi would also need to get the converter up to operating temperature same as the Lexus.

MP4.2+6.0

It depends on the exhaust construction, exact tuning, how they certified vehicle to the EPA, etc. Thus, the closer in the converters to the motor, the faster they light off as an example; how agresssively they do shift program to hold lower gears, another. The engineers in the first instance may have also made certain design decisions, in part interpreting rules that likely really deal w/ internal combustion and not EV, etc. And different companies will come to different conclusions, and big hybrid players like Toyota may get scrutinized while small players like Audi/VW/Porsche may get little attention. All speculative.

You would find the definite answer driving it from cold, but presumably like me you've concluded it hardly exists on the road or with dealers. One of the local dealers had two that passed through momentarily, but both pre sold, like their remaining allocated one this year is. The owner's manual might well tell you too if you can get ahold of one that is hybrid specific. Finally, a few things from the Q5 hybrid SSP document:

This one seems mostly technobabble to me w/ few real specifics:

The introduction of the MED 17.1.1 engine
control module (ECM) with a triple-core
processor also made it possible to implement
an innovative thermal management system. The
result was improved fuel economy and reduced
CO2 emissions via heat balance optimizing
in the vehicle. This was accomplished by
keeping all parts and assemblies (for instance,
the engine and transmission) under thermal
load (connected to the cooling system) within
their optimal temperature range for greatest
efficiency.

Then the one below with better specific clues, italicized for the obviously relevant ones and seemingly netting to it basically needs to be at least 50 degrees F to get going in EV only mode from a cold start assuming the car isn't further cold soaked. Seems to imply that in a mild climate (like here in SF Bay Area) it could start in EV. But a question I would still have from the emissions side is once the gas motor kicks in the first time, does it stay on until the ECU has basically decided it has reached initial operating temps. Could be again EPA hasn't realized to regulate this and Audi went one way and Toyota another. The text from the SSP meanwhile:

Operating Elements

By pressing the Extended Electric Driving Mode
Button E709 (EV mode), the driver can extend
the limits of all-electric driving, using the overall
power of the e-machine.
Requirements for driving in EV mode:
• Speed less than 62 mph (100 km/h)
• Charge level of the high voltage battery > 30%
• Temperature of the high voltage battery
greater than 50°F (10°C)
• Coolant temperature of the internal
combustion engine between 41°F (5°C) and
122°F (50°C)
• Ambient temperature equal to or greater
than 50°F (10°C)
• No DTCs in 12 volt starter system
• Altitude less than 13123 ft (4000 m)
• Not in tiptronic mode
• System capability electrically equal to or
greater than 15 kW
• Stop enabling signals are present
(from Start/Stop System)

ErnestHouse

I test drove the Hybrid today and it does in fact work as an EV cold. Caveat: This was in Florida with an outside temperature of 85F.

Driving the car around town and in residential streets, I could see a thoughtful driver clocking some high mileage. I was able to keep the gauge at 29MPG without even trying in city traffic. The Hybrid drivetrain was seamless but if you wanted to concentrate on it, there's a decent control that gives you a good idea of how your driving is affecting performance. The car delivers on V6 performance with a better than 4 cylinder thirst.

MP4.2+6.0

I am up in the CA Sierra’s where temps have been below freezing at times. The net is the Hybrid related EV functions are basically the same with cold outside temps. I can easily get it into EV mode even with the outside temp down in the 20’s (F), and it turns on relatively quickly from a cold start. Looking back at the spec’s where Audi says the ambient temperature has to be 50 degrees F as a requirement for EV mode, either that is an outright miss, or they are referring to something like the air temp. surrounding the battery pack. Since the battery pack is cooled from cabin air ducted to it (or if hot, via an A/C circuit take off), basically if the car isn’t frigid inside, it would meet the 50F spec even if very cold outside. Later this winter it will probably be outside at times at 0F or below overnight and I can check further from much colder starting interior temps.