What would be your most efficient engine design?

[SSSnail]

When take away the requirements for camshafts?

The future of automobile is that the internal combustion engine will no longer requires camshafts to operate valves, but rather solenoids controlled by the PCM. You will see some of the most efficient engines coming to your favorite automobiles very soon, as I think BMW is perfecting this technology.

The energy required to operate the camshafts could be ~30% of output, and if the camshafts are no longer used, the solenoid can be placed anywhere feasible. That means no more engine torque affecting steering, launch, etc... and balance can finally be achieved with not much efforts.

So, with that in mind, what is your dream engine design?

 

[CurseTheSky]

My dream engine design definitely wouldn't be a normal piston (or Wankel rotary, or hybrid, or electric) engine.

 

[sdifox]

I would say diesel powered generator feeding motors

damn, that is not an engine is it...

<--fail

 

[brblx]

The future of automobile is that the internal combustion engine will no longer requires camshafts to operate valves, but rather solenoids controlled by the PCM.

yeah, i don't think this is happening any time soon.

the amount of electrical energy needed to overcome valve spring tension thousands of times a minute would be significant. and an electrical failure could be catastrophic.

 

[43st]

I'd guess a fuel cell to either an ac or dc electric motor.. if/when the technology becomes cost competitive.

 

[MotF Bane]

A small nuclear reactor driving electric motors on each wheel. Perfect torque at all ranges, no shifts, all four wheels provide forward and reverse functions, and you can drive for years without needing to refuel.

Now I just need the time machine to go fetch this.

 

[Bignate603]

Possibly something that could recover waste heat that normally gets thrown away. Maybe a six cycle engine (uses water injection into the cylinders after the typical exhaust stroke, it turns to steam, expands and makes some power) or a normal engine hooked to a stirling heat engine that can extract power out of the exhaust heat.

 

[brblx]

if you're talking about internal combustion, that's what it's all about- managing heat losses.

i really liked BMW's turbosteamer concept, though it was still based on exhaust heat; i'd like to see something that actually tries to capture heat from the cooling system, but then you run into the problem of the engine becoming more inefficient as coolant temps go down.

 

[SSSnail]

yeah, i don't think this is happening any time soon.

the amount of electrical energy needed to overcome valve spring tension thousands of times a minute would be significant. and an electrical failure could be catastrophic.

But that's just it, right now the energy requires to operate the valve springs is tremendous, so these solenoids won't need to have as stiff springs as you would have on a normal camshafts/spring setup.

It is happening, and it will be here soon; as I've said, BMW is perfecting it, not developing it.

If valves fail to open, it won't be as catastrophic as one would imagine, as I think there would be redundancies such as multiple multiple electrical paths, multiple valves (just like now), etc... Unless you're talking about total failure of the electrical system, which then would render the car useless anyways.

Let's say a few valves would fail to open or closes, you wouldn't have immediate engine failure, but an adverse operating condition that shouldn't be prolonged. It wouldn't be catastrophic.

 

[Arkaign]

All red-blooded motorheads will always love the good old ICE, and I have a big soft spot in my heart for the cammy noise of a loping 440, 351, and so on.

That said, while they work well, and have been continually improved over the years to astonishing degrees, they are pretty inefficient even under great circumstances. When you factor in the energy used in extraction, the energy used for refinement, the energy used for distribution, and then add the final losses during use in an ICE, it's pretty bad really.

What could be really efficient? There are all kinds of ideas. The most feasible at this time imho would be the widespread use of Thorium-cycle small nuclear electric plants combined with electric vehicles. Of course that brings in another inefficiency : losses in charging and frankly the battery technology could use a few more generations of improvement. Beyond that, there are wild things possible with more scientific and engineering breakthroughs :

mobile fusion reactors small enough to power transportation needs

a breakthrough that really makes solar to electric conversion a high yield result

wireless electric transmission/reception

antimatter or charged particle propulsion

gravity manipulation for the purposes of movement

How long until these things are ready? Some could be here in a couple of decades, some maybe never.

 

[Billb2]

When take away the requirements for camshafts?

...internal combustion engine will no longer requires camshafts to operate valves, but rather solenoids controlled by the PCM.

Back on topic.

F1 has been doing that for years, so I would suspect Mercedes and BMW followed shortly by Honda to introduce it in 1-3 years.
But shortly there after electric power will be the rage.

 

[SSSnail]

Back on topic.

F1 has been doing that for years, so I would suspect Mercedes and BMW followed shortly by Honda to introduce it in 1-3 years.
But shortly there after electric power will be the rage.

Yes, F1 has been doing it (at least 4 years) and I believe BMW will be the first to introduce this to the masses.

So back on topic, given that the entire cams related assembly would be obsolete soon, this frees up the need for cams placement, belts, chains, etc... so the possibility are endless for more efficient internally combustible engine designs.

I was just wondering if there are any engineers here in ATOT garage would come up with any wild design concepts based on these information.

 

[adlep]

AFAIK the most efficient engine is either a Sterling (Heat) engine or an electric motor.
http://en.wikipedia.org/wiki/Steam_turbine

That is why cars of the future should be powered by electricity and nothing else...

Edit: I have an idea then for a hybrid diesel/steam electric generator...
Here is how it works...

1. Diesel engine produces mechanical energy and heat waste.
2. The heat waste ins being absorbed by a coolant water.
3. The coolant water absorbs the heat, turns into a steam which is being used used to power a steam turbine.
4. The steam engine increases the overall efficiency of a generator.

 

[MiataNC]

Depends on what you consider "efficient".

A Wankel Rotary engine has 3 moving parts. (no pistons, cams or valves). It makes more more power per liter than a typical ICE by a wide margin, and takes to turbo/super charging like a duck to water.

Yet it is by no means "efficient" at burning fuel, and only in recent years has seal material technology made it possible to use "reliable" in the same sentence as rotary.

 

[canadageek]

Yes, F1 has been doing it (at least 4 years) and I believe BMW will be the first to introduce this to the masses.

So back on topic, given that the entire cams related assembly would be obsolete soon, this frees up the need for cams placement, belts, chains, etc... so the possibility are endless for more efficient internally combustible engine designs.

I was just wondering if there are any engineers here in ATOT garage would come up with any wild design concepts based on these information.

Solenoid operated valves are a long, long way away. have you ever tried to push open a poppet valve? it requires one hell of a lot of force. now try doing this 200 times a minute. there simply isn't any way to produce a system that can do this in an environment such as an engine bay in a car. F1 uses pneumatic valve SPRINGS, which use air pressure to close the valves and a camshaft to open them.

TLDR: no, BMW won't be bringing us electric (or pneumatic) valves for a long time.

 

[brblx]

that^

also, whoever said solenoid operated valves would require less spring tension is incorrect. the spring strength must be adequate to prevent valve float, which the strength of the opening mechanism has no impact on.

edit- of course, that's moot if you're talking about using pneumatic or electromechanical action to close the valves, as well, but i don't think anyone has ever tried that? i could be wrong, i don't keep up with f1 tech.

 

[zmatt]

I remember someone tried to make a ceramic engine some time back to better manage heating, but it was too fragile.

IMO with available tech the best bet for most people with every day boring cars would be small displacement turbocharged diesel or N/A gasoline engines. You can get very high mpg form them and they are powerful enough to get your average compact car around town with decent performance.

 

[exdeath]

The energy required for electromagnetic valves is IMMENSE; so much in fact that cams are actually more efficient. With the latest continuously variable timing (and lift?) now, there really isn't a need for electromagnetic valves. There are numerous issues with no solutions at the moment. It won't be happening any time soon.

That said, the most efficient engine with no valves is a gas turbine engine, esp a turbine-electric hybrid. A continuous combustion gas turbine is vastly more efficient than any kind of cycling engine; the only problem is that it is efficient *only* when high continuous power levels are required; it's only more efficient than a piston engine making the same power.

In other words, a 5,000 HP turbo shaft is incredibly more efficient than a 5,000 HP piston engine, but not a 150-400 HP piston engine, because, well, it's still 5,000 HP /facepalm. Basically plot a curve with power/efficiency of piston engines and turbine engines, and somewhere up well beyond what is required for a automobile, the lines cross; turbines have a minimum power range and initial cost before their efficiency gains can shine.

Small turbine-electric serial hybrids would be something to think about; something like one of those scale model aircraft or cruise missile turbines running at a fixed RPM only driving a generator. You get the most for the fuel, and you isolate the main problems when discussing jet engines in cars; inability to start/stop or change RPM quickly.

 

[exdeath]

A small nuclear reactor driving electric motors on each wheel. Perfect torque at all ranges, no shifts, all four wheels provide forward and reverse functions, and you can drive for years without needing to refuel.

Now I just need the time machine to go fetch this.

You'd have to shift at some point. I don't know of any electric motors that can do 36,000 RPM.

 

[TraumaRN]

Well I think some companies are doing the best they can right now to improve the ICE to be as efficient as it can be and for right NOW it's the best thing we have. I'm looking at Ford and Toyota specifically, both have near beltless or totally beltless ICE engines in their hybrid vehicles, especially Toyota.

Ford wise finding little ways to reduce pumping losses, like their Cam Torque Actuated (CTA) iVCT(and I quote from Ford Media site)

"technology that uses available camshaft torsional energy rather than pressurized oil to phase the camshafts.This allows for a smaller displacement oil pump versus traditional hydraulic VCT systems for improved fuel economy.

This method uses torsional energy to move the camshafts similar to the way a hydraulic ratchet works. The system takes oil from one side of the phaser and channels it to the other side, rather than draining one side and filling the other as with a traditional hydraulic system. This allows the CTA system to work more efficiently at all engine speeds and it requires a smaller oil pump, which equates to lower parasitic energy loss.

CTA reduces oil pump flow requirements by approximately 25 percent, producing a fuel economy benefit up to 0.4 percent. In addition, the CTA-based system responds more quickly than a traditional hydraulic oil actuated VCT system, improving tip-in performance feel and contributing to horsepower gains."

Hey .4percent is .4percent

Personally I'd love to see automakers go towards more of the modified Atkinson cycle you see hybrids running on. Instant FE gain at the loss of some torque but given that most cars these days have plenty of power ....of course it'll never happen.

 

[43st]

You'd have to shift at some point. I don't know of any electric motors that can do 36,000 RPM.

&#8776;22" dia. = 69.12" circ. x 36,000 rpm = 2488320 in/min = 2356 mph

I must be missing something from your statement.. but I don't think you need an electric motor that can go that fast.

 

[exdeath]

&#8776;22" dia. = 69.12" circ. x 36,000 rpm = 2488320 in/min = 2356 mph

I must be missing something from your statement.. but I don't think you need an electric motor that can go that fast.

No that's a bit high, I just thought 6k RPM x 6 speed in an instant and threw out a number without regard for the fact that you don't start out at 0 RPM after each shift.

You'd still need a higher RPM than most electric motors can sustain and need at least a two speed.

 

[EightySix Four]

No that's a bit high, I just thought 6k RPM x 6 speed in an instant and threw out a number without regard for the fact that you don't start out at 0 RPM after each shift.

You'd still need a higher RPM than most electric motors can sustain and need at least a two speed.

Tesla v1 had a single speed gear box and worked fine despite the lower top speed.

 

[exdeath]

Tesla v1 had a single speed gear box and worked fine despite the lower top speed.

Interesting, I could have sworn it had a two speed. What's the top speed limited to?

 

[EightySix Four]

Interesting, I could have sworn it had a two speed. What's the top speed limited to?

I was incorrect, the two speed unit cuts a 3.9 0-60 and the one speed could only run a 5.7 0-60. The top speed of the two speed unit is listed as 125mph at ~13k rpm. All the original single speed units were upgraded to twospeeds once the two speed design was finalized.