Stratified Charge DI with EGR (was: AFM measurement/backpressure)

[Bernd Felsche]

Ade + Lamb Chop writes:

>At 09:34 11/03/00 +0800, Bernd Felsche wrote:
>>>>None that I can recall.  Lucas/Bosch systems use them, and
>>>>patent leasees of them.
>>>>Numerically probably MAP is most common, then hot wire, and then
>>>>combos of MAP/hot wire.

>>>So what is the best way?? The rover system uses MAP and inlet air
>>>temperature...

>>Even hot-wire is passé. :-)

>How does hot wire work?? Is is a little heater that uses X power then you
>measure the temperature... more airflow the more heat is taken from the
>heater?? Surely you would also need air temperature, or am I completly off...

Done with either a reference wire or by a separate temp sensor.

>>The latest Bosch MED Motronic (for direct-injection (DI),
>>stratified-charge gasoline engines) uses a version of hot-film
>>(HFM5) that's sensitive to the flow direction. That's necessary with
>>the DI system because they run it with WOT at low loads, using
>>controlled, external EGR to reduce the engine's output - by varying
>>its displacement if you like.

>That sounds incredible complecated... So presumuable there is no direct
>throttle cable... just a fly by wire pedal and ecu does the rest???

Throttle-by-wire. The driver sets the amount of torque required by
the position of the pedal. The ECU adjusts throttle, EGR (up to
70%), injection and ignition accordingly.

The complication has its rewards; 15% less fuel consumption, partly
due to increased "volumetric efficiency" because the throttle is
often wide open... better find an updated abbreviation to replace
WOT!

The engine uses quantity-regulation at low load; the torque
developed depends on the amount of fuel injected. The amount of air
sucked in and ignition timing have little effect on torque.

-- 
Real Name: Bernd Felsche
    Email: nospam.bernie at perth.DIALix.com.au
     http://www.perth.dialix.com.au/~bernie - Private HP
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