My FIL had a similar low tech solution in his Hillman Minx. Knock it into neutral going down hill or when approaching lights or a junction. Scared us to bits.
The DKW also had the same system if you remember the DKW? Frightened the life out of me when I first drove one as part of our advanced driver training was to use the engine for gentle braking when approaching traffic lights, yield signs etc and where it was safe to do so.
The answer is it depends on the situation, so potentially yes and no. However if you are freewheeling, then there is nothing for the engine to do, and if its not being driven by the momentum of the vehicle through the gearbox, so if the engine is running it must be using some fuel.... Where as if the engine is still being driven by the cars momentum, modern vehicles will actually cut the fuel completely.
Our Mini Clubman JCW coasted ie disconnected the gearbox from engine in green mode and it most definitely made a difference on rural and A roads-at least 2-3 mpg better overall average ie it usually did 34mpg but we managed 36 out of it if we used green mode-which was not that often tbh as the car was made for fun! As for it being dangerous that's not true and not how they teach you to drive these days-it used to be the case-use the engine braking to slow the caras brakes weren't reliable but they are now and learners are advised to do a fair bit of coasting ie upt to lights etc and use their brakes; as they say brakes are cheaper than engines or gearboxes.
However with an automatic you would simply lift your foot off the pedal if approaching traffic lights, yield etc. Although "coasting" you are still in gear and the engine is doing the braking.
Most vehicles that include a freewheel system, the engine is automatically disconnected from the drive, other wise it won't freewheel.
Before Japanese motorbike two strokes introduced positive engine lubrication as the norm,, you had to watch the over run on the home grown products. If you think freewheeling in a car is hairy, a bike makes it much more fun.
Some years ago my wife use to own a Yamaha 125cc motorbike sometimes it would not start and pushing it and putting it in gear after a 12 hour shift just to get home it was fun but tiring.
You’re only the second person I have come across who drove 2 stroke Saabs. I wonder why a non eastern bloc country went for 2 stroke?
DKW were based in Saxony, Germany which became East Germany after WW2 until German reunification - the original Saab two-stroke was based on a pre-war DKW design.
I think DKW became Audi?
Is that why you always had a puff of smoke when you accelerated again? Another friend who was my boss had the 2 stroke Wartburg which I think had the DKW engine. He physically added2 stroke oil to the fuel tank, but for many years had the wrong mixture until I corrected him. No more smoke when driving up a hill etc.
A while back I posted a thread re GDR Towcar of the Year with this picture of a Wartburg near us. The guy now has another one, blue, right hand drive with towbar too, and in very good condition. He also has an original Tipo ( Golf Buster) and original Panda which he drove to North Cape. Will cost him a fortune to electrify his stable.
My friend had the estate version which he imported into Rhodesia and he did a lot of mileage in it. The front half shaft snapped and he was unable to sourced replacement so had to scrap the car.
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