Throttle bladeless engines
 

In one of the technical Formula 1 websites recently there was an interview with the head of engine development at Renault.
As part of the interview they got onto the subject of throttle body design and he was asked if there were no restrictions in this area what system would the use, His answer was no throttle body at all.

Without the engine freeze, what would we be seeing now with regards to throttle design?
"Actually, without any regulations you probably would not have throttles any more. In 2011 when teams were using maps to power off throttle blown floors, throttles were left (more or less) open the entire lap to maintain exhaust flow, and torque and ignition maps alone were used to control the torque produced. If the rules had not been clarified, then the air intake would have been left fully opened and torque would have been controlled completely by ignition. This would have made very efficient cars."
Renault explains F1 engine throttles - F1technical.net

It peaked my interest in regards to Ecomodding with the last sentence.

My thoughts are that without the restriction the pumping loses would be reduced.
I do recall a conversion years ago with a guy who talked about experimenting with engine control by advancing and retarding the timing. That would be easy to try with a distributor based ignition system. I’m picturing a distributor that was rotated by the throttle pedal/cable.
Obviously someone with a better practical understanding of electronics and EFI could setup an ECU to shift the spark and fuel timing.

Has anyone else here done any experiments along these lines or had similar thoughts.

I have a throttleless engine in my truck.
Its pretty old technology.

How did your truck manage if it was old technology?
What if you floor it.. how does it then know you need to take in more air and add more fuel, and add more timing..?

diesels = no need for throttling. injection timing and amount determine output.

LOL. Good one.
BMW's valvetronic ditched the throttle valve for variable lift intake valves.
Valvetronic - Wikipedia, the free encyclopedia
Not the same as F1, but still sort of neat.

My engine was built by cavemen, so it still needs the throttle plate while starting from a full stop and when rev-matching after a bump start. :P

Interesting to think about but I think there are a couple of considerations that make an F1 car different to a road vehicle.

They will have been operating, when on throttle, for much of the time at or near WOT anyway. We, in road cars, don't spend very much, if any time at WOT/full load.

When the driver doesn't want to accelerate there is still that benefit to be had by blowing air through the engine and directing it so that it generates down force via the body. If they can get the down force in that way they can back off the wings and find less drag along the straights. Any associated loss in engine efficiency (non optimum fuel and ignition) is offset by the reduced wing drag.

There is a most efficient ignition timing and air:fuel mixture for each engine, fuel and load. While it is possible to alter the power output solely through changing those things the efficiency with which fuel is turned into useful work reduces away from those optimum settings. Road cars operate under much lighter loads, with a wider range.

I do wonder if some (small) gain in reduced pressure drag might be achieve by directing the exhaust flow on a road car though.

Well it seems like everyone is looking for an engine that is throttleless, has high compression, a turbo and lean burn.

I see no need to reinvent the wheel.

There are still good reasons to persist with spark ignited engines. For a start the constant volume (on a PV diagram) combustion process that approximates how they burn the fuel is fundamentally more efficient than the constant pressure process that approximates compression ignition.

Lose the pumping loss and bump up the compression (ethanol, methanol or CNG?) and the SI engine will be more efficient than CI.

SI are lighter and smaller for the same power output. CI always run lean so can't ever use all of the air they pump through them. That means they have to be bigger and heavier to compensate. CI are inherently heavier anyway because they, in effect, always operate under knock. The slower combustion rate required, limited by the rate the fuel and air can mix, also limits the power they can make. (Anticipating "What about turbo's?: at the equivalent level of development; SI can also be turbo.)

The fuel systems and emission controls are inherently more complex and expensive with CI over SI.

I try not to think about that. Because exhaust gasses are hot and corrosive. I have centrifugal-pumped engine cooling air to work with though.

A Revolutionary Split-Cycle Design | Scuderi Engine

From their Engine Performance Data pdf:
with equal sized cylinders. Mismatched cylinder displacement and 3.2 bar of 'Constant Knock Margin – 40% Turbo Efficiency' gains 13.4% on those figures.

i ASSUME some vehicles have this done already.... mostly trucks, where the tailpipe turns out after the rear wheels and they have a small section of the tailpipe "clipped".

That puts the exhaust into the most turbulent air available, shortening the time for the fumes to dissipate? :confused:

http://ecomodder.com/forum/member-fr...29-0-large.jpg
Exit the exhaust into a high-bypass duct like a turbo-jet uses. That will increase the volume 2-3x and cool it with some loss of velocity. One stage, not two. Note the serrated trailing edge on the duct.

I find the absence of emissions controls to be simple and cheap.

Perhaps some of the "dress tips" that most newer cars have do something similar? If not, why not? If they're there anyway...

But car manufacturers don't. (And it is Ecomodder.)

In 1984 they did.

Its eco for economy as in saving money. I only see about 2% of the people on here trying to eco their vehicles to make them run cleaner.

Plus my diesel runs a lot cleaner now than it ever could have in 1984. I happen to like burning all the fuel and getting as much energy out of it as possible before it leaves the engine bay.

Basically the only reason to retain the throttle-plate is braking power...

in that instance, i'd much rather have an electric pump run as needed for vacuum, or in the case of something that would need more than what that could handle, a crank driven unit.

I have hydraulicly boosted brakes, no vacuum.

No Jake brake?

How Jake Brakes Work

It wasn't about vacuum. I meant engine-braking power, which is enhanced in the engines with throttle blade. No wonder Diesels are fitted with supplementary engine-braking devices.

Compression release engine brake - Wikipedia, the free encyclopedia

Smaller diesels do not have a jake brake.
Newer diesels with VGT will use the turbo charger to act as a exhaust restriction brake.
My HE351VE turbocharger has this ability but I locked it out because I have no intrest in exhaust braking.

I respect that.

That kid (not I), who'd just graduated high school and was driving truckloads of grain past it in the 60s, sure did. :)

Even without a VGT, it's not impossible to fit an exhaust-brake in a smaller Diesel engine, and since it's cheaper than a Jake-Brake it's also widely used in heavy truck engines in overseas markets.

Old school flapper valve exhaust brakes were responsible for lots of blown head gaskets in the 70s and 80s.
I am going to avoid anything like that.

They're still widely used back here and no problem at all, altough nowadays transmission-mounted braking retarders are getting more popular in heavier vehicles.