2010 LA AUTO SHOW PREVIEW: Audi Details The Q5 HYBRID

1. The hybrid car engine operates frequently stop-start. The frequently stop start reduce drastically the turbo charger duration, because of the low pressure of engine oil at stand still.
In other hand the normal aspiration engine starts or turbo charged engine starts need lot of energy. Most of the recuperated energy used for start the engine.
(Therefore Atkinson engine implemented in RX450h)
2. The Li-ion battery required a liquid cooling occours comlexity of the system, high (heat)energy loss and possible lower duration.
3. There is a traditional transmission in Q5 hybrid, which also increase the complexity. There are lot of energy loss between the transmission and the electric motor at driving and at the deceleration. This mean, should not been effective brake energy recuperation.
4. There is a hydraulic operated wet clutch between the electric engine and petrol engine,which also increase the complexity and the energy loss.
5. The system works like a parallel hybrid with the electric engine release with clutch system. The paralell hybrid efficiency should not be similar with the full hybrids.

Summary:
Audi Q5 hybrid system is too complex with the extrem high risk of technical defects. (Turbo charger, multi clutch system, traditional auto gearbox, liquid cooled li-ion battery...).
The powertrain system has plenty of elements where there are lot of energy loss. (permanent 4WD, auto gearbox with clutches...)
The RX450h has an Atkinson engine designed to frequent stop-start.
There is no gearbox, only a planetary gearset putting together the petrol engine and the electric motor.
The rear wheel driven by electric motor.
Still the most sophisticated hybrid SUV is RX450h.
Energeticall

"need lot of energy"..."complexity of the system"..."possible lower duration"..."lot of energy loss...this mean, should not been effective brake energy recuperation"

This seems like a very subjective criticism without ANY FACTUAL DATA to back it up. Just how "inefficient" is this system compared to the Lexus??? I don't believe you can even answer that. You are either a politician or a Toyota/Lexus employee (my guess).

Preliminary Audi hybrid systems have proven excellent at efficiency, so my guess is that this new model will improve upon those results. I will hold my judgement until I see and test the finished product.

What outsider says is based exactly on factual data. Even though numbers are not yet known, I wouldnt be surprised it the Q5 is nowhere as efficient as RX450h.

Ugh, just give me the rock solid modern 6 cylinder turbodiesel, PLEASE.

The calculation is easy. The brake force (which needed to recuperate) is 100%.
The 4x4 mechanical loss is ~ 5%.
The A/T mechanical loss is ~ 10%.
The hidrodynamic torque converter slip is 5-10% on drive and 70-90% on engine deceleration mode. (Therefore there is not engine brake with A/T models.)
Result of efficiency= (100%-5%)*(100%-10%)*(100%-70%) = 25,6%
This can be the brake force recuperation efficiency on ideal case.
The calculation does not take into consideration the mechanical losses on tyres, on wheel bearings. The calculation does not contain the heat loss on li-ion battery.
The ToyLex systems essencial is that the electric motor(s) directly drives the wheels, without any transmissions. The electric motor(s) independ(s) from petrol engines, means they can recuperate the breke force with high efficiency.