RE: Koeningsegg to Qoros in one step

[V8 FOU]

I think this is a great idea.

why not go the whole distance and make the actuators desmodromic? With no spring to work against, there would be less work for them to do.

[Daston]

My car doesn't have Cams already

This is an interesting idea, would this mean the end to headgasket issues? I assume there will still need to be a separate head.

[AER]

Max_Torque said:

12% economy improvement in lab conditions. Hmm, i smell a rat.......

Well, since it would allow cylinder deactivation as well as early inlet valve closing for pumping work reduction, it might be feasible, but you know the developers are clutching at straws when they quote "fuel economy" improvement rather than fuel consumption reduction. The percentages get a little bigger for the same change...

[wst]

annodomini2 said:

Concept engines for this have been done for decades, the problem is making the actuators reliable.

They would need a non-interference, but open stop position in the event they lose power (electrical, pneumatic, hydraulic).

Why would it need an open stop position?

[PunterCam]

We're all so desperate to have everything all the time - compromise is what gives character.

[Spannerski]

Ford have been using oil pressure to fire the injectors on their F-150 pickups Powerstroke diesel engines for sometime now.
It does require massive oil pressure, the correct oil and regular oil changes.

However when things go wrong it is expensive and complicated to repair.

I can only imagine what it's like adding pneumatics as well.

But then modern vehicles are getting more and more complex to the point where you now cannot replace bigend bearings etc... on some vehicles.

Just my Farthings worth.

[Evilex]

framerateuk said:

scarble said:

Could every car be camless in the next 10-20 years?

Yes, they'll all be electric!

And we have a winner!

[Evilex]

Daston said:

My car doesn't have Cams already

This is an interesting idea, would this mean the end to headgasket issues? I assume there will still need to be a separate head.

Mazda owner? Or Leccy...

On a more serious note, I assume there'd still be cylinder heads in the accepted sense, if only to allow easier access to the valves for assembly and maintenance.
Sod having to take the engine out, crankcase off, crankshaft, rods and pistons out just to withdraw a damaged valve down one of the bores because there's no access from the top end!

[kambites]

Evilex said:

Sod having to take the engine out, crankcase off, crankshaft, rods and pistons out just to withdraw a damaged valve down one of the bores because there's no access from the top end!

I suspect the huge majority of engines never have their head(s) removed and of those that do most will be to replace the head gasket, which wouldn't exist if the head and block were one piece.

Admittedly the number might be rather higher if you have a non-mechanical system controlling the valve opening on an interference engine.

[anonymous-user]

V8 FOU said:

I think this is a great idea.

why not go the whole distance and make the actuators desmodromic? With no spring to work against, there would be less work for them to do.

Technically true, but the hysteretic loss in the spring is really rather small you know!

[zeppelin101]

AER said:

Well, since it would allow cylinder deactivation as well as early inlet valve closing for pumping work reduction, it might be feasible, but you know the developers are clutching at straws when they quote "fuel economy" improvement rather than fuel consumption reduction. The percentages get a little bigger for the same change...

Cylinder deactivation doesn't yield that significant a benefit all things considered, the constraints for most vehicles severely limit the load and speed range over which it can be used so it really only has a benefit on very large engines with high cylinder count. Figure on 1.5-2% tops for a V8 reducing significantly for a 6 and being almost 0 for a 4 cylinder in real world conditions.

Pumping reductions are valid but that won't get remotely close to making up the extra 10% because there are side effects to combustion which mean it isn't a linear relationship. Friction reduction? Still won't be enough to make up the significant chunk that is missing.

Maybe in combination with cooled low pressure EGR for mid to high load you might get nearer but even then the engine bumps into other limitations which cap the benefit without doing something dreadfully complicated that probably won't package in a vehicle.

Fuel consumption is only half the battle now-a-days anyway, the rest is all particulates and emissions control.

[RumbleOfThunder]

Bring it to mass market now! Technologies like these are key to the ICE prolonging it's life. Interesting vid from a while ago, Koenigsegg adapting it to work in a Saab.

https://www.youtube.com/watch?v=Bch5B23_pu0

[k-ink]

Interesting. Although rather like inventing a slightly better oil lamp, just as electric street lighting was being installed.

[AER]

zeppelin101 said:

AER said:

Well, since it would allow cylinder deactivation as well as early inlet valve closing for pumping work reduction, it might be feasible, but you know the developers are clutching at straws when they quote "fuel economy" improvement rather than fuel consumption reduction. The percentages get a little bigger for the same change...

Cylinder deactivation doesn't yield that significant a benefit all things considered, the constraints for most vehicles severely limit the load and speed range over which it can be used so it really only has a benefit on very large engines with high cylinder count. Figure on 1.5-2% tops for a V8 reducing significantly for a 6 and being almost 0 for a 4 cylinder in real world conditions.

Pumping reductions are valid but that won't get remotely close to making up the extra 10% because there are side effects to combustion which mean it isn't a linear relationship. Friction reduction? Still won't be enough to make up the significant chunk that is missing.

Maybe in combination with cooled low pressure EGR for mid to high load you might get nearer but even then the engine bumps into other limitations which cap the benefit without doing something dreadfully complicated that probably won't package in a vehicle.

Fuel consumption is only half the battle now-a-days anyway, the rest is all particulates and emissions control.

I don't agree with your analysis at all. Of course, much of this depends on what your baseline is, but mostly we're talking drive-cycle fuel consmption here. BMW were claiming close to the 10% mark by introducing their valvetronic systems - effectively early inlet valve closing for VE reduction. Cylinder deactivation is worth more than just pumping losses too, since the effective surface/volume ratio and therefore thermal efficiency improves. Holden were claiming around 1L reduction in a 12.9L/100km official figure with the L76 engine, which puts it within a bull's roar of the 10%-ish claim - way more than your 1.5-2% claim. As for your ideas on sixes and fours, you'll have to quote some sources to back your claims because everything I have read contradicts this too.