2 stroke thread (with occasional F1 relevance!)

[coaster]

The company next door does alot of Detroit diesel stuff, every so often they throw away a V8 diesel block and next time they do i will try to get some photos, i have observed the blocks;
1/ V angle is about 75 degrees
2/ It is wet sleeved quite deeply.
3/ There are single and crossplane crankshafts
4/ Main bearings in the region of 120mm
5/ A ring of 18mm holes at the bottom of stroke in the sleeve
6/ Roots super charged pressurisation, no overlap.

Swap the diesel fuel for E85 and scaled down to a 2 litre V8 with a dry sump, gear driven ohc exhaust and sleeve valve intake with variable timing all weighing less than 90kg and that sounds like a plan for f1, super charger with compounded twin turbos would be nice.

[NathanE]

What has died is any future for ICE as we know them - gasoline fuelled. Possibly Manolis has realised this and abandoned all his projects?
There is it seems a potential (atmospheric pressure) storage system for hydrogen in the offing. Maybe if ICE is to survive it will adapt to running on hydrogen. For sure, hydrogen powered fuel cells are expensive and thus far are the only zero CO2 alternative to batteries for mobile propulsion.

I guess then that an interesting though for this thread is whether 2T hydrogen engines would be feasible to increase specific power output?

I imagine lubrication will be an issue due to fuel contamination, but this presumably is an issue for 4T too - any other thoughts?

[Tommy Cookers]

I guess then that an interesting though for this thread is whether 2T hydrogen engines would be feasible to increase specific power output?
I imagine lubrication will be an issue due to fuel contamination, but this presumably is an issue for 4T too - any other thoughts?

(agreed) with hydrogen .....
heavily-turbocharged very lean running is likely (otherwise there's issues with NOx and combustion pressure rise)
it doesn't matter if some unburnt fuel goes past the exhaust port
so yes to 2T

some are trying hydrogen in those huge marine 2 stroke diesels (with or without liquid fuel to trigger combustion ???)
and maybe Detroit diesel could start some production ? (having stopped in 1995 ?)

[Hillclimber]

Hi All - Whilst 0n holiday I have read this complete thread, very interesting read.

I build and race two stroke engined (Hill Climbs) cars here in the UK and my latest creation uses an Evinrude V8 - 3.6 litre powerhead with a CVT transmission. I use 8 Mikuni Super BN carbs with an ignition system I made myself etc.etc.

It works OK ,BUT I utilised the original exhaust system ,converging all 8 exhausts into one final tuned outlet which I have had to silence(muffle) to achieve acceptable db of 108.

I have looked at modifying the engine to have 8 seperate ports for expansion chambers, EFI etc.

Being 77 years old, I have one more big project to achieve. So I am looking to modify my spare V8 to fit rotary valve exhaust, allowing me to use a 4 stroke type exhaust, a fresh pressurised air injection system to purge the exhaust gas, an EFI system for both direct and after reed injection (for crank lubrication etc.) plus a supercharger.

I had planned to do this using my usual technique - trial & error.

However seeing the analytical skills on here, maybe someone can say - this will not work! I do not see a reason why it cant.

Peter

[Tommy Cookers]

.... modifying the engine to have 8 seperate ports for expansion chambers, EFI etc.

the Honda NR500 had in each bank 4 rods and 4 crankpins moving in unison
with a similar crankshaft a 2 stroke V8 would need only 1 expansion chamber per bank
there's no vibration issue
or similarly unconventional but less extreme configurations would allow eg 2 chambers per bank

crankshaft configuration might be significant to the new engine development

[Pinger]

I guess then that an interesting though for this thread is whether 2T hydrogen engines would be feasible to increase specific power output?

I dug deeper into hydrogen storage and with the new Plasma Kinetic system and existing industrial gas bottles (at 175 bar) it works out at 100kg of weight for each 1kg of hydrogen. 1 kg of hydrogen has the same energy value as 3.5 litres of gasoline.
Toyota's Mirai stores at 700 bar and contains circa 5kg of hydrogen in a 122 litre carbonfibre tank. A 122 litre tank to carry the equivalent of 17.5 litres of gasoline.
The only hydrogen ICE I can envisage would be stationary with hydrogen piped to it.

I imagine lubrication will be an issue due to fuel contamination, but this presumably is an issue for 4T too - any other thoughts?

Probably the crankcase of the simplest 2T would be a necessity as the blow-by associated with hydrogen contains both water and hydrogen. One will kill the oil in no time, the other is an explosive risk. The degree of positive crankcase ventilation required to circumvent that is what a simple 2T does already!

Generally though, if hydrogen is to be utilised in an ICE then absolutely 2T is the first choice.

[Pinger]

Hi All - Whilst 0n holiday I have read this complete thread, very interesting read.

I build and race two stroke engined (Hill Climbs) cars here in the UK and my latest creation uses an Evinrude V8 - 3.6 litre powerhead with a CVT transmission. I use 8 Mikuni Super BN carbs with an ignition system I made myself etc.etc.

It works OK ,BUT I utilised the original exhaust system ,converging all 8 exhausts into one final tuned outlet which I have had to silence(muffle) to achieve acceptable db of 108.

I have looked at modifying the engine to have 8 seperate ports for expansion chambers, EFI etc.

I'm impressed with all of that!
But....

Being 77 years old, I have one more big project to achieve. So I am looking to modify my spare V8 to fit rotary valve exhaust, allowing me to use a 4 stroke type exhaust, a fresh pressurised air injection system to purge the exhaust gas, an EFI system for both direct and after reed injection (for crank lubrication etc.) plus a supercharger.

I had planned to do this using my usual technique - trial & error.

However seeing the analytical skills on here, maybe someone can say - this will not work! I do not see a reason why it cant.

Peter

....I'd skip doing the above.
There will be more losses than gains driving all that you want (supercharger, etc). Example: if you intend closing the exhaust port before its normal closing point you will incur more compression work but not get the expansion work in return as you will still be opening the exhaust port early for blow-down. The opposite of the Miller/Atkinson cycle which is currently popular in 4Ts as it enhances efficiency.
Depending how developed your current exhaust system is - there are (IMO) probably more gains to be had further optimising it.
Unless you really are hell bent on a project that is!

[coaster]

Go old school, 8 expansion pipes and figure out a set of reeds for each intake crankcase chamber, maybe a large plenum above the reeds and holley 650 carb.
Reeds from fibreglass or carbon.
The exhaust pipes could converge after the seperate expansion chambers and into a single 3 inch supertrap muffler.
Carefully phase the ports intake for maximum overlap, hog out the transfer ports with a die grinder.
Run 98 octane, 12 to 1 compression, knock sensor ecu for spark.
Oh yes.

[Pinger]

Hi All - Whilst 0n holiday I have read this complete thread, very interesting read.

I build and race two stroke engined (Hill Climbs) cars here in the UK and my latest creation uses an Evinrude V8 - 3.6 litre powerhead with a CVT transmission. I use 8 Mikuni Super BN carbs with an ignition system I made myself etc.etc.

It works OK ,BUT I utilised the original exhaust system ,converging all 8 exhausts into one final tuned outlet which I have had to silence(muffle) to achieve acceptable db of 108.

I'm interested in more info on the above eg, engine orientation, CVT used and how configured, exhaust lay out, etc, etc.
Photos would help.

I'm also in the UK and have Mercury engines (one 3 cylinder and two six cylinders) and a Formula Ford chassis all doing nothing.

[gruntguru]

I dug deeper into hydrogen storage and with the new Plasma Kinetic system and existing industrial gas bottles (at 175 bar) it works out at 100kg of weight for each 1kg of hydrogen. 1 kg of hydrogen has the same energy value as 3.5 litres of gasoline.
Toyota's Mirai stores at 700 bar and contains circa 5kg of hydrogen in a 122 litre carbonfibre tank. A 122 litre tank to carry the equivalent of 17.5 litres of gasoline.
The only hydrogen ICE I can envisage would be stationary with hydrogen piped to it.

You need to dig even deeper. Yes - 1 kg of hydrogen has the same energy value as 3.5 litres of gasoline - however combustion cars (without hybrid transmission) can only convert about 20% of that energy into propulsion whereas a hydrogen fuel cell car is closer to 60% giving a ratio more like 10 litres of gasolene to 1 kg of hydrogen. In addition the FCEV will always be hybridised (only requires the addition of a small battery) and will re-use much of the braking energy in city driving.

A quick Google search reveals the Mirai has a range of 650 km. The fuel tanks weigh 87.5 kg (92.5kg full) similar to a full 60 litre tank of petrol.

[Pinger]

The only hydrogen ICE I can envisage would be stationary with hydrogen piped to it.

You need to dig even deeper.

I was referring to ICE and hydrogen with regard to the known storage methods for hydrogen. Storage methods which only exist in fuel cell EVs - hence mentioning them.

[Tommy Cookers]

.. combustion cars (without hybrid transmission) can only convert about 20% of that energy into propulsion

can ? - F1 ICEs can convert over 50%
and ....
a hydrogen (SI) ICE should need no throttling (for partial power)
a hydrogen ICE could be the ultimate in heat dilution (as the explosive range is so wide)

re ICE design ....
hydrogen's very high mass-specific heating value can be a mirage
its stoichiometric mass-specific heating value is important ...
its stoichiometric gas volume is freakishly high
its latent heat trapping is high

[coaster]

Hydrogen implies an exhaust cam and a supercharger.
How could a transfer style crankcase be lubricated?

[gruntguru]

.. combustion cars (without hybrid transmission) can only convert about 20% of that energy into propulsion

can ? - F1 ICEs can convert over 50%

. . . and some production engines have peak thermal efficiency of 40% - however in practice can only convert something like 20% of fuel energy to propulsion. Mostly because (as you are well aware) real world operation involves very little time spent at the peak efficiency operating point.

[gruntguru]

.. combustion cars (without hybrid transmission) can only convert about 20% of that energy into propulsion

re ICE design ....
hydrogen's very high mass-specific heating value can be a mirage
its stoichiometric mass-specific heating value is important ...
its stoichiometric gas volume is freakishly high
its latent heat trapping is high

The simple solution to much of that is DI. Injecting H2 after exhaust closure ensures the VE (air) is comparable to petrol. The stoichiometric heating value per kg air:
For petrol is 41/14.7 = 2.78 MJ/kg
For H2 is 120/34 =3.53 MJ/kg - an incrrease of 26% - potentially 26% greater power.