2 stroke thread (with occasional F1 relevance!)

[Pinger]

By the way,
the “ex-engineer” of Orbital (now involved in the “sliding cylinder project”) may know why the big and promising project of Orbital (i.e. to install their direct injected 2-strokes in cars) ended the way it ended.

Because the auto manufacturers were making shed loads of money selling high NOx diesels? The higher the sticker price, the more they make on finance. Complication adds/justifies cost. Just one of the existing prejudices.

[Muniix]

Water cooled ECU for outboards and fuel cooled for the sleds - seems to be the way of things.

Isn't it the injector driver that requires cooling, modern ECU run cool and use low power and offer high performance.

That the ECU requires cooling (the one on my car is one side of the airbox and finned) is no surprise and in OBs and sleds I guess they use as cooling medium what is at hand (air would add bulk on OBs and sleds). But, atomisation was what held DI back as back in the 1980s when first tried using mechanical injector pumps the required (small) droplet size was unobtainable. Sophisticated injectors amplifying the pressure and/or air blast is what made DI possible.
Still it is hampered by short available injection time at high loads (if charge loss to the exhaust port is to be avoided) and the technology is complex - relative to IDI or carbs.

[Pinger]

Isn't it the injector driver that requires cooling, modern ECU run cool and use low power and offer high performance.

Probably! That's just me demonstrating my complete lack of understanding of all things electronic.

[Muniix]

My father had a Batam, not all four Stroke engine are heavy 77kg for a V10 with over 1,000 HP is not heavy.

Because some one engineers one that heavy is evidence of the Engineer only.

A 26 kg single with 78hp four strokes have been engineered. 146 HP at 42 kg will be available by 2020, 180 HP with mild hybrid and multiphase combustion.

Cherry picking information can prove anything.

Marc, that light "Batam" 4T V10 of "over 1,000 HP" which your father had, do support your claim, post a citation link..

Also a post showing a 'kosher' dyno chart of the "26 kg single with 78 hp" 4T on test.. lets see that 'cherry'..
Since 'the proof of the pudding', even one cherry based, is in the results per taste, ah, test.. & not in 'magic' claims..

Though it was all pretty obvious.

My father had a Batam as mentioned in your cycle world article.

The V10 is obviously the Ilmor BRV. Which was banned precisely due to these specifications.

The 26 kg 78 HP bike engine was the final Development of the CRF450 with the Bishop head after they​ got the injector vaporisation working as it is a clear highly optimised flow straight into the cylinder, vaporisation was critical. Not counting the ECU or the fuel pressure pump of course.

[Muniix]

By the way,
the “ex-engineer” of Orbital (now involved in the “sliding cylinder project”) may know why the big and promising project of Orbital (i.e. to install their direct injected 2-strokes in cars) ended the way it ended.

Because the auto manufacturers were making shed loads of money selling high NOx diesels? The higher the sticker price, the more they make on finance. Complication adds/justifies cost. Just one of the existing prejudices.

I really don't think there is much future in automotive diesel engines, or compression ignition like the GDCI gasoline direct compression ignition as they need to be built with the mass of a Diesel.

The extra mass, expense and complexity required due to CI with high acoustic combustion energy with Diesel and gasoline and emmisions will not be cost effective when EU 7 emmisions are reached.

Really the Torque figures of IC engines are fraud, they only produce this at a very narrow rpm range, unlike electric which is effectively always available.

[Tommy Cookers]

well likely the electric motor's nominated peak torque is fraud as it's one that is not available continuously
the starter motor is the clear and spectacular example of this

not unrelated, a gearbox is almost as important to an EV vehicle as it it is to an ICE vehicle
unless in the happy-clappy world where they pretend an ICE prime mover in an ICE/electric vehicle is a range extender

btw I read today that crankshaft offset doesn't reduce piston friction, just redistributes it within the cycle

[J.A.W.]

Really the Torque figures of IC engines are fraud, they only produce this at a very narrow rpm range, unlike electric which is effectively always available.

So, Marc, you are unable to provide evidence of your claims, such as a link to certified dyno charts or even weights.
(& its Bantam, as in diminutive chook, not Batam , or Batman, or other fanciful things).

& still you don't read the data cited here..

Such as your ill-founded assertion: "...IC engines are a fraud..."

If you refer to the basic 30 year old road going 2T Yamaha twin dyno* chart posted a couple of pages back,
-not only was it capable of a peak output of ~165 hp/ltr at a low 9,000 rpm..
.. but it made over 30ft/lb torque for more than 4,000 rpm to that point.

2T engines have advanced significantly since then too, obviously.

*rear wheel power.

[Muniix]

well likely the electric motor's nominated peak torque is fraud as it's one that is not available continuously
the starter motor is the clear and spectacular example of this

Yes, well noted I was only just about to review heat dissipation of various EM drives and identifying their peak & continuous heat and power capability. Investigating peak power handling, heat dissipation and mass of light weight core less motor generator designs using advanced materials.

not unrelated, a gearbox is almost as important to an EV vehicle as it it is to an ICE vehicle
unless in the happy-clappy world where they pretend an ICE prime mover in an ICE/electric vehicle is a range extender

That is why the Tesla uses different ratios for front and rear drives. Proportioning power to the most efficient motor for the given situation saving on the gearbox mass. He is not a silly man. The car acceleration g force is higher than its braking force due to the weight transfer to larger tyres on the rear.

The efficiency range deferential between worst and peak is with a much smaller range with EM drives than it is with ICE.

btw I read today that crankshaft offset doesn't reduce piston friction, just redistributes it within the cycle

My guess going on the dual Crankshaft arrangement analysis is that the multiplier effect of pressure due to rod angle on the side thrust typically gives a net gain as the pressure differential is favourable to less total piston friction over the full cycle.

Taking into consideration the difference in heat and pressure released during stoichiometric combustion due to the modified piston motion a small ~5% increase in rotational torque at high offset is achievable.

In combination with ultra lean combustion start of combustion and the heat dilution/burn rate can be optimised to take advantage of the pistons motion to provide improved torque. Liner surface temperature with electric cooling pump can also by controlled to optimise combustion, heat release, oil viscosity these are all pretty well understood now that we can implement them into engine control strategies by calculating the heat flux from cylinder pressure sensor data, injected fuel mass and trapped air mass.

Direct injection of gaseous fuel can reduce the energy losses in compression by cooling the charge increasing density reducing the pressure.

The offset also provides increased piston velocity in the latter compression stroke this increases​ mass turbulent kinetic energy providing faster burn rate and extending​ the lean limit slightly. In geometrically viable dual Contra-rotating crankshafts the effect is significant.

[Muniix]

Really the Torque figures of IC engines are fraud, they only produce this at a very narrow rpm range, unlike electric which is effectively always available.

So, Marc, you are unable to provide evidence of your claims, such as a link to certified dyno charts or even weights.
(& its Bantam, as in diminutive chook, not Batam , or Batman, or other fanciful things).

& still you don't read the data cited here..

Such as your ill-founded assertion: "...IC engines are a fraud..."

If you refer to the basic 30 year old road going 2T Yamaha twin dyno* chart posted a couple of pages back,
-not only was it capable of a peak output of ~165 hp/ltr at a low 9,000 rpm..
.. but it made over 30ft/lb torque for more than 4,000 rpm to that point.

2T engines have advanced significantly since then too, obviously.

*rear wheel power.

You just contradicted your self with the torque range from the impressive twin engine dyno chart being;
18-46 proves my statement
That Power and Torque claims of IC engines are only available in a very special situation. Supporting my claim that EM engines claims are more realistic.
I don't see some peoples posts because I see too many erroneous claims which bug me. Due to previous vendors repeated false claims of their products​ performance that failed miserably that ultimately led to a co-worker passing​ from a heat attach. Even though I stepped in the day before and worked around the situation for him giving him Xmas holidays. Rip Pat 26-Dec-91

in the graph you mention​ I can't see of the twin 2T engine because I choose not to have my intelligence insulted in silly childish comments that contradict the known facts. For example they include;

Making claims of EcoMotors without reading their postmortem is for idiots.
Claiming Revetech are gone when they have just contracted an engineer to do design changes of their engine for a client.

I choose to block his posts to save everyone. It is just not worth my time, people with his exact behaviour lead to the death of a work colleague.

That dyno data has not been released. But anyone familiar with engines, combustion with any inclination to understanding intake flows can by looking at the Bishop valve geometry and the clearly unique unobstructed flow that may present some advantages to VE gains at the high end due to the behaviour of air being compressible, useful in over rev not previously available.
Understanding the amount of air it can trap and injected fuel mass at x or y rpm will easily achieve 76 to 80 hp at safe piston velocity if one increased rod length, which they can do due to the Bishop valve heads low profile.

Given the increased heat release of high tumble ratio even at compromised BSR of the CRF450 and the associated reduction of heat losses due to optimal combustion chamber geometry, no heat quenching features typically of poppet valve engines. Really is not that hard for anyone familiar with combustion to believe 80 hp is viable. No magic involved. Just well understood physics.

To continue development of IC engines we need to evaluate every Innovation and its features, finding complementary features in other Innovations through detailed simulation that shows a clear advantage over the traditional design. Due diligence and risk assessment, testing to meet endurance.

Australia had to tear down its Automotive industry, so it could build a new industry based on modern proven methodology. Out with the old biases, opinions etc. Replaced with science and technology.

[J.A.W.]

Really the Torque figures of IC engines are fraud, they only produce this at a very narrow rpm range, unlike electric which is effectively always available.

So, Marc, you are unable to provide evidence of your claims, such as a link to certified dyno charts or even weights.
(& its Bantam, as in diminutive chook, not Batam , or Batman, or other fanciful things).

& still you don't read the data cited here..

Such as your ill-founded assertion: "...IC engines are a fraud..."

If you refer to the basic 30 year old road going 2T Yamaha twin dyno* chart posted a couple of pages back,
-not only was it capable of a peak output of ~165 hp/ltr at a low 9,000 rpm..
.. but it made over 30ft/lb torque for more than 4,000 rpm to that point.

2T engines have advanced significantly since then too, obviously.

*rear wheel power.

You just contradicted your self with torque from
18-46 proves my statement
(eff me, they are everywhere)
in the graph​ I can't see of the twin 2T engine because I choose not to have my intelligence insulted by in silly childish comments...

Making claims of EcoMotors without reading their postmortem is for idiots...

I destroyed their life and will continue to rid the world of such opinionated...

That dyno data has not been released...

I may soon be able to release... ...possible due to the many advantages of dual crankshafts.

Marc.. again you fail to demonstrate any meaningful level of credibility.. & no data, only off-topic disorganisation..
..you cannot even read a basic dyno chart.. - let alone provide one - that supports your claims..
FYI, I have made no comments or claims about EcoMotors, & I have not "contradicted" myself.. but you have, repeatedly..
..by your "silly childish ( & churlish) comments"..
& as for your frankly bizarre "I destroyed their life..." - IMO, that presents - as deranged.. & is quite improper, here..

[J.A.W.]

In all cases, the heat loads on the piston(s) are significantly increased - but then that's always the case when the power output is upped!

Hi Pinger, see here: http://3cyl.com/mraxl/performance/perftech.htm

This shows how amenable a basic 2T is to thoughtful, but simple (& inexpensive, by 4T values) performance mods.
The old Kawasaki 750/3 thus ~doubles its output, but not at the cost of a 'peaky' or catastrophically hard - tune..

[Pinger]

Hi Pinger, see here: http://3cyl.com/mraxl/performance/perftech.htm

This shows how amenable a basic 2T is to thoughtful, but simple (& inexpensive, by 4T values) performance mods.
The old Kawasaki 750/3 thus ~doubles its output, but not at the cost of a 'peaky' or catastrophically hard - tune..

Not sure I agree with his analysis of how -ve suction from exp' chambers aids crankcase filling at higher rpm - other than any residual vacuum remaining when the transfers close. It can't draw straight through from cylinder to inlet (like a reeded motor can) as the inlet port is closed around that crank angle. Suspect he is overlooking inertial effects.

Why, when he shows power and torque curves plotted with the Y-axis calibrated in hp and lb.ft, do the lines not cross at 5250 rpm (his cross at 7000)? The RDLC YPVS plots cross at 5250.

What do you use for pipes on your 750 J.A.W.? Three separate pipes or three-into-one?

[Pinger]

Because the auto manufacturers were making shed loads of money selling high NOx diesels? The higher the sticker price, the more they make on finance. Complication adds/justifies cost. Just one of the existing prejudices.

I really don't think there is much future in automotive diesel engines, or compression ignition like the GDCI gasoline direct compression ignition as they need to be built with the mass of a Diesel.

The extra mass, expense and complexity required due to CI with high acoustic combustion energy with Diesel and gasoline and emmisions will not be cost effective when EU 7 emmisions are reached.

Yep. I think the tide has turned against Diesel but I doubt the manufacturers know which way to jump right now.
For sure they have GDI but are they going to wait until particulate filters are mandated before fitting them or risk another public outcry when particulate emissions become more widely known? And it is still a complex and expensive engine to build (albeit slightly cheaper than CI).
Full electrification isn't an option for everyone as many (especially in cities where they are of most benefit) do not have access to home charging. At the workplace possibly, but what to do at weekends and holidays? There is also the environmental aspects of mining the required materials. For the manufacturers though, they can market electrification as a new technology and price commensurately. The same can not be said for a 2T ICE - unless it is buried within a heavily electrified vehicle. And still I haven't seen an available off-the -shelf viable 2T. Even if the CITS unit does reach production, I can see aspects of it which OEMs will find objectionable.
At least Renault is giving 2T a whirl but with gas exchange solely by side by side poppet valves (tried and abandoned previously by many) and the slow rpm forced upon it with CI combustion, I'm not convinced it has a bright future.

There is of course the possibility of electric vehicles being hooked up to the electricity grid at all times other than when being driven, giving said grids storage capacity they have hitherto only dreamed of. Smoothing out the demand peaks and troughs easing generation matching over a 24 hour period is there to be had - but so far, no takers.

Are we agreed Muniix that the TJI/lean burn concept (applied to 4T) is the most likely to succeed in the short to medium term?

[J.A.W.]

Why, when he shows power and torque curves plotted with the Y-axis calibrated in hp and lb.ft, do the lines not cross at 5250 rpm (his cross at 7000)? The RDLC YPVS plots cross at 5250.

What do you use for pipes on your 750 J.A.W.? Three separate pipes or three-into-one?

P, the basic convention is to show the TQ/HP cross at the maths constant of 5252 ( where possible, most diesels wont).
But it does not alter the findings, since he is running a machine on a dyno, not a model simulation on a computer,
& his charts show the hp figures comparing curves before & after modification, rather than TQ/HP..

Yes, I have tried various pipes, inc 3-into-1, a set-up which works best when the header section is as short as practicable..
..see the Hirth triple for an exemplary unit.. & they sound very 'Ferrari V12' like, but lose out on top-end power..
..compared to well-designed 3-into-3 pipes..

I may try a balance pipe system on the inlet side..
.. so the marked reverse pulse from the piston shutting the inlet duct, is fed to the next opening inlet cylinder..
..rather than blowing back through the carb & upsetting the mixture/wasting fuel..

[J.A.W.]

I think the tide has turned against Diesel but I doubt the manufacturers know which way to jump right now.
For sure they have GDI but are they going to wait until particulate filters are mandated before fitting them...

Full electrification isn't an option for everyone as many (especially in cities where they are of most benefit) do not have access to home charging. At the workplace possibly, but what to do at weekends and holidays? There is also the environmental aspects of mining the required materials. For the manufacturers though, they can market electrification as a new technology and price commensurately. The same can not be said for a 2T ICE - unless it is buried within a heavily electrified vehicle. And still I haven't seen an available off-the -shelf viable 2T.

There is of course the possibility of electric vehicles being hooked up to the electricity grid at all times other than when being driven, giving said grids storage capacity they have hitherto only dreamed of. Smoothing out the demand peaks and troughs easing generation matching over a 24 hour period is there to be had - but so far, no takers.

Are we agreed Muniix that the TJI/lean burn concept (applied to 4T) is the most likely to succeed in the short to medium term?

P, a couple of things..

1stly, battery tech will have to get way, way, more advanced, in terms of size, power potential, cost &,
recharge time before they can offer a real/practicable alternative to hydrocarbon fuels.

2ndly, emissions legislation/controls are as much a 'political' issue as a health promotion/technical capability matter..

The inherently fundamental 2T advantages of power density/mass/cost have yet to be specifically applied to cars,
at least in a coordinated package, in the current era, but it does not follow that 2T values thusly - do not still apply..

& there are reasons why ( just as for DI) that the "TJI/lean burn concept" actually applies better to 2T, than to 4T..