Retro 'mild' hybrid

[Air-Hybrid]

Okay, so one way to be eco is to keep that old metal on the road.
Also, once you've got the classic car bug it's real difficult to shake

At present I have a rather nice Hillman Imp from 1968 which after it's had some rather nasty underfloor welding done and is back on the road will be far too pretty to be buggering about with.

However, being a car-nut who is not really at home with 'pretty' I am intending to sell the present imp and replace it with something a little more rustic - ie. a tattier imp

Now these cars, apart from their groovy 60's looks (that I think are iconic even now), are not the lightest small car (compared with a Mini of the time) or the most aerodynamic shape. However I appreciate the shape they are very much, so am interested in other ways to make 'eco' modifications.

Incidentally, the imp engine was a real missed opportunity for the Roots group in that it was incredibly cleverly engineered, ally block giving 50bhp from the tiny 875cc engine (with sport head -like mine has). But it was rushed to market and penny pinched on production - leaving a bad taste from first cars made that was never quite lived down.

Sorry about 'wittering on' but I wanted to lay out some details about the perceived 'project' & I've not even mentioned hybrid-ing yet!
So two key fact about the layout of an imp, it's rear engined and the the block is tilted over to the drivers side with the (ineffective) cooling fan and rad on the other. On this basis, a common performance 'trick' for imps is to move the rad to the front with a long pipe run through the car. This is a sensible design as the ally block temp needs to stay well in limits.

So to the hub of the idea! You now have a largish space to the left of the engine bay right next to the back of the engine with the fan-belt pully facing you (longitudinal engine) - here you put a smallish elec motor/generator and a small battery pack as low centre-of-gravity as possible. Another thread describes a mild hybrid idea that is like driving downhill all the time - simplistic I know, but it got me thinking...

.... I await the ridicule!

[Daox]

Interesting little car. I say go for it.

[gasstingy]

Help me out here, as my imagination is suffering a bit. I got the part of relocating the radiator and adding an electric motor/generator and a small battery pack. Then, (the short version would be fine) how does it help? Is it a way to restart the engine after you've shut it off for stopping?, or some way to reduce the strain on the engine while going down the road?

Any way you look at it, I say it's a great idea! I'm a big fan of older cars. They look great and get approving nods from people even when you are going slower than the average rushed / stressed commuter. I too visualize a subcompact project car in my future, but was thinking either electric propulsion, or 3 cylinder turbo-diesel like Jack McCormack put in Max. (Mothers Automotive X-prize entry Locust)

[320touring]

Hi, welcome!

this sounds like an awesome plan!

imp would be a quirky yet practical setup..even better would be a van as the shape is more aero..

There's also a thread on here about supercharging for better efficiency, and who could pass up the opportunity to put a rootes type charger on an imp?

its also worth working out what weight could be saved-so you can put in batteries without too much suspension upgrading.

best of luck!

[NachtRitter]

What you're describing sounds very similar to what brucey's doing in this thread (different car of course, but same idea): http://ecomodder.com/forum/showthrea...ger-13932.html

[Air-Hybrid]

Originally Posted by Air-Hybrid

I await the ridicule!

.... and ..... ha ha, the ridicule didn't arrive *gets out of the foetal position!*


Sorry if the explanation was a bit confusing in places, I went off on a tangent about the car and then ran short of time!

Thanks again all 3 for the confidence boost!
Thanks to Daox additional for finding a nice clear pic of the Imp and its engine layout.


So I'm going to have a go at expanding this a bit more:

Originally Posted by gasstingy

...how does it help? Is it a way to restart the engine after you've shut it off for stopping?, or some way to reduce the strain on the engine while going down the road?

In answer, my ideal is -the best (most efficient) I can manage- on pretty meagre finances! I currently drive (in what I consider to be) a reasonably efficient manner (by normal standards but not on the eco-modder scale I'm sure). I will turn the engine off at (or sometimes approaching) long traffic lights and drift up to junctions or stationary traffic. So for me a auto-start-stop system is handy, but I doubt would make much difference. >As an aside, can you guys put me straight on the switching-off policy? Other people have said that more fuel can get used in restarting (but I don't know the principles & whether old or new cars differ).<
Anyway, going back to the analogy of the engine assist being like going downhill (on a flat road) I would have thought a system that delivered an almost constant torque would be some bit easier to 'wire' than a more advanced hybrid (as a newbie I expect I am underestimating it though).
That said, if I had a system that for negligible weight would 'puff' my little engine over whilst stationary (idle jet 'off') that would be pretty cool. However for the money and time that building such a system would entail it would certainly be a bonus if it can give an assist here and there! A good analogy would be my flat spot pump - when I (occasionally) push down hard on the 'gas' it sends a squirt of neat petrol down the venturi and the vacuum pulls the dissy round a tiny bit. I was thinking that for starters this would be a perfect job for our electric assist. No crudely chucking a chunk of unmixed fuel at the cylinders or buggering with the timing (so much), just a firm push from the e-motor. Of course, at this stage you may all be saying 'you need to go injection anyway', but it's easier (for me at least) to picture in mechanical terms.

I also expect you are beginning to wonder how I hope keep my mild hybrid topped with electricity. It was the mild hybrid route that most attracted me after I found an article on GM's BAS (belt alternator starter) system. I was already fairly certain that some flavours of motor could operate almost as efficiently as generators and finding the BAS system appears to prove it. It also seems perfect for a light small engined car as the power cost of adding weight is that much worse by have two separate units.
So the (as of today, only academic) question is what cycle of operation would I need to keep an averaging load on my little 875? I understand that as with any hybrid I'm only going to be carrying 'dead' weight on a ideal straight motorway with no braking or accelerating, but I know that (at least with the sports head & a progressive-choke Webber at least) my MPG falls quite considerably in town driving (careful as I am). Here I could get some real savings.

I have just thought of the (lets call it) over-aggressive engine braking being a real nice way to help keep that battery pack full. The only real downside is ideally it would be better to have the 'regen' on the front wheels and adding another generator would be especially complex on an imp.


Phew (again)... tired fingers, stopping now.

ps. They did make a van-shape imp, but alas it's not as nice a shape...

[Neddy Seagoon]

Ever tried to change the thermostat on a Imp?? I had one back in the 70's, great little car but the gear change was a bit iffy. It got to the stage where I could pull the engine out in no time flat, just pulled it out of the back of the car. Also make sure the timing chain is in good nick or you could up up with more bent valves than you could shake a stick at.
Good luck, Neddy.

[Air-Hybrid]

Originally Posted by NachtRitter

What you're describing sounds very similar to what brucey's doing in this thread (different car of course, but same idea): ...

Thanks for the link. I missed your post yesterday as it went on only just before my post and I missed it. I did have a trawl around before posting this topic and had spotted the very same thread. It was a lot to take in at one 'sitting', but I have been back today & am pleased to note the OP also cited GM's BAS system as a bolt-on approach to mild hybridisation.
I have also looked at what RobertSmalls has to say about using a motor-assist.

Originally Posted by Neddy Seagoon

Ever tried to change the thermostat on a Imp?? I had one back in the 70's, great little car but the gear change was a bit iffy. It got to the stage where I could pull the engine out in no time flat, just pulled it out of the back of the car. Also make sure the timing chain is in good nick or you could up up with more bent valves than you could shake a stick at.
Good luck, Neddy.

Hi Neddy (good name!). Luckily I haven't had to change the thermostat yet, but have become quite practised at having the engine/transaxle in and out, much is the pity. Now it looks as if it will have to come out once more to deal with the ongoing battle with rust. I also had problems with gear-change, first down to the hydraulic clutch master cylinder and then a buggered gearbox. There are several ways and means to tighten up the gear selection, but I'll be happy with them just working at all for now!