Faster car with less than 100 kg/h fuel flow

[PlatinumZealot]

Maybe oil consunption and seal failures?
It uses face seals, in high temperature conditions, granted at least the seals are only acted on in one direction. I don't know if this setup is more demanding than the seal in a rotary engine or a seal in some sliding valve valved engines?

Toyota had a well developed prototype, and another company.... Bush (?) had the BRV engine running. I really dont know how much these valves contribute to efficiency so I cannot say if they would have helped the case of switching back to NA engines. Have to re-read some of those sources.

[Jolle]

https://www.youtube.com/watch?v=Tq2vrqqlSNg

pretty impressive.... but, what if Audi just welds 6 Ducati Panigale V2 engines together? 930HP from 6.0l at 10.750 rpm.

[gruntguru]

That's a good question. There are the usual barriers to disruptive technology plus - in the case of the Bishop Rotary Valve, I believe it was developed to the point where it was superior to poppet valve technology of the time in terms of performance but would have required a lot more work to get emissions and fuel efficiency to a point where it could compete in road cars.

[Tommy Cookers]

the rotary-valved Ilmor F1 engine was replaced by a poppet-valved engine that gave equal power ....
by using shorter stroke and rpm increased correspondingly (proportionate to the square root of stroke)

clearly there is some (relative) amount of valve 'area' beyond which increased area gives zero benefit
(relative to engine requirements) poppet valve 'area' increases disproportionately with increasing bore:stroke ratio

so (post pneumatic 'valve springs') RVs had little or no potential benefit at the freakishly large B:S ratio of late NA F1

and remember F1 has been limited to 4 poppet valves per cylinder though 7 or 8 have been used elsewhere

[Big Tea]

the rotary-valved Ilmor F1 engine was replaced by a poppet-valved engine that gave equal power ....
by using shorter stroke and rpm increased correspondingly (proportionate to the square root of stroke)

clearly there is some (relative) amount of valve 'area' beyond which increased area gives zero benefit
(relative to engine requirements) poppet valve 'area' increases disproportionately with increasing bore:stroke ratio

so (post pneumatic 'valve springs') RVs had little or no potential benefit at the freakishly large B:S ratio of late NA F1

and remember F1 has been limited to 4 poppet valves per cylinder though 7 or 8 have been used elsewhere

Just wondering like.... I assume the big problem with poppet valves is clearance and lift.
Has anyone ever tried opening the valve the other way? into the port rater than the cylinder? lifting instead of depressing.
I know there would be all sorts of sealing problems, but with modern technology it could be surmountable on an F1 engine if not a road car. Say the cam directly holding the valve closed 'desmo style' or some locking system. Would there be any benefits to this?
Flow,cooling etc?

(who said it is better to keep your mouth shut and be thought a fool than to open it and remove the doubt?? )

[Jolle]

the rotary-valved Ilmor F1 engine was replaced by a poppet-valved engine that gave equal power ....
by using shorter stroke and rpm increased correspondingly (proportionate to the square root of stroke)

clearly there is some (relative) amount of valve 'area' beyond which increased area gives zero benefit
(relative to engine requirements) poppet valve 'area' increases disproportionately with increasing bore:stroke ratio

so (post pneumatic 'valve springs') RVs had little or no potential benefit at the freakishly large B:S ratio of late NA F1

and remember F1 has been limited to 4 poppet valves per cylinder though 7 or 8 have been used elsewhere

Just wondering like.... I assume the big problem with poppet valves is clearance and lift.
Has anyone ever tried opening the valve the other way? into the port rater than the cylinder? lifting instead of depressing.
I know there would be all sorts of sealing problems, but with modern technology it could be surmountable on an F1 engine if not a road car. Say the cam directly holding the valve closed 'desmo style' or some locking system. Would there be any benefits to this?
Flow,cooling etc?

(who said it is better to keep your mouth shut and be thought a fool than to open it and remove the doubt?? )

Clearense and lift was a problem when machining wasn’t so advanced as it is now plus the advances they made in springs (pneumatic or not). Also, the thought here “can we make a NA engine that is as efficient as a turbo engine” this isn’t a problem. Valves are the problem in getting the revs up, in the search of more power. With higher revs, the efficiency drops dramatically.

In cars, with a few exemptions, the quest for power and efficiency is answered by a turbo, in both racing and on the road.

For turbo engines displacement and revs are not important, so you can run low revs, having no problems with valves whatever.

[J.A.W.]

Maybe oil consunption and seal failures?
It uses face seals, in high temperature conditions, granted at least the seals are only acted on in one direction. I don't know if this setup is more demanding than the seal in a rotary engine or a seal in some sliding valve valved engines?

Toyota had a well developed prototype, and another company.... Bush (?) had the BRV engine running. I really dont know how much these valves contribute to efficiency so I cannot say if they would have helped the case of switching back to NA engines. Have to re-read some of those sources.

To be fair, back in the day Toyo Kogyo did make their 4-rotor 'Mazda' rotary-piston win at Le Mans,
& that was effectively, a form of 'rotary valve' engine too of course - albeit it is fundamentally an
inefficient unit as far as fuel/heat efficacy goes, even if up there in bulk/weight/packaging terms.

[PlatinumZealot]

Ok Gonna repost this..The rotary valve has been a topic beaten to death on the forum.. but since the average combustion knowledge across the forum has been enhanced by discussions on the V6 hybrid it might be worth looking back on some advantages disadvantages of the BRV...

Here is some insight on the seal and durability.. interestingly they compare it to a piston ring... maybe a little biased here? Piston rings are circular, and are radially tensioned.. the BRV seals are spring loaded strips with corner seals. The lubrication is a bit different too. but any anyhoo..

https://www.v-eight.com/multimedia/pdf/AutoTechBRV.pdf

Whilst the rotary valve engine has demonstrated breathing capacity that is at least equivalent to the best F1 poppet valve engines, it has the huge advantage that it does this without the dramatic reduction in life that occurs with F1 poppet valve heads. As inertia induced loads in the valve train are absent in the rotary valve, the forces that destroy the poppet valve heads are also absent. Further the mechanical and gas loads seen by the valve are essentially independent of speed.The only issue affecting durability that changes with engine speed is the peripheral speed of the sealing elements and the bearings.

The peripheral speed of the valve over the sealing elements is approximately 80% that of the maximum F1 piston ring velocity, this is of little concern. In production poppet valve engines, engine life considerations require changes that greatly curtail their breathing capacity from the level achieved in F1. This is clearly not the case with the rotary valve and Bishop’s research suggests a production rotary valve has a breathing capacity up to 45% greater than that observed on current 4 valve production engines.

[Tommy Cookers]

..... Bishop’s research suggests a production rotary valve has a breathing capacity up to 45% greater than that observed on current 4 valve production engines.

what does 'up to' mean ?
and if true how would the RV engine behave ?

doesn't a road 1600cc SI engine (for clarity let's think NA) at best breathe (say) 1500cc of mixture per cycle ?
reduce capacity to 1100cc to suit 45% better breathing and the cylinder CR would need to be reduced - not ideal ?
unlike the poppet-valved turbocharged engine - which can use charge cooling to help maintain cylinder CR

we might be persuaded that at some desired partial torque the CR isn't an issue .... but ....
if RV engine's smaller size helps efficiency - don't we then need further throttling to get down to that desired partial torque ?

[gruntguru]

"45% better breathing capacity" could not mean 45% improvement in VE throughout the rpm range. At a stretch you could infer 45% indicated power increase if the bottom end was capable of the higher revs enabled. Under normal driving conditions (lower revs) the VE would be the same as poppet valves.

[Rodak]

......Bishop’s research suggests a production rotary valve has a breathing capacity up to 45% greater than that observed on current 4 valve production engines.

Well, what would be the effect of running RV on a turbo engine? Would the increased flow through the port mean that boost could be lowered to achieve the same power, as there would be less energy expended forcing the charge past the valves into the cylinder?

[PlatinumZealot]

Maybe the benefits are less pronounced with turbocharging....

But considerations might be how the tumble flow is affected.

Slight off-topic.. The internet can be a dangeous place! Someone copied without my permission a drawing I did years ago on here that showed my interpretation of a rotary valve engine. They put it on their page of rotary valved engines alongside the BRV!!
I am not even trained in engine design... and have no clue if my concept is even viable! And here someone is using it as a reference! Its in figure 3 in the page below.. Lol so careless!

https://njneiva.wixsite.com/rotaryvalve ... of-the-art

I aborted that design because of spacial reasons in the cylinder head. Bearings ans seals were difficult to fit with the size of valve i wanted.

[Rodak]

He didn't credit you, did you call him on it? Plagiarism is really frowned on at universities and can get you tossed........ Worth an email IMO.

[gruntguru]

......Bishop’s research suggests a production rotary valve has a breathing capacity up to 45% greater than that observed on current 4 valve production engines.

Well, what would be the effect of running RV on a turbo engine? Would the increased flow through the port mean that boost could be lowered to achieve the same power, as there would be less energy expended forcing the charge past the valves into the cylinder?

The torque/power curve of a well designed supercharged engine is very similar to the curve for the same engine NA. At a given RPM (to a reasonable approximation):

supercharged torque/power = NA torque/power X MAP