Lightweight ICEs and Fuel Cells

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Retry
08/09/19 07:19 PM
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LIGHTWEIGHT ICEs & FCEs

The standard, most common Internal Combustion Engine in use in the 31st century has hardly changed from the ICE in the 21st century. However, alternatives to these engine types using more advanced (and more expensive) designs and materials have existed for some time.

The Light Internal Combustion Engine replaces the regular steel alloys with other alloys, the three most common being nickel-based, cobalt-based, and titanium-aluminide based superalloys, whose strength is retained better than most steels at high temperatures, allowing the pistons to operate at a higher temperature and resulting in higher thermal efficiencies, and a modestly lighter engine for the same power. Light ICEs are also far more likely than standard ICEs to use more exotic thermodynamic cycles than the common Otto cycle like the Atkinson cycle, so they're usually slightly more fuel efficient than regular ICEs.

The Light ICE is somewhat uncommon, especially compared to the regular ICE, precisely due to the exotic material inputs. The materials are more difficult to find replacement parts for, and the acquisition cost increases the cost of the engine near that of fuel cells, which lessens the primary advantage of the ICE. It's still fairly cheap compared to everything else, so that combined with most model's flexible fuel consumption finds the Light ICE used in mid-range combat vehicles in between the capabilities of regular ICEs and fusion vehicles.

The XL ICE is rare. The XL ICE was developed around the same time that Endo-Steel was invented and replaces the regular steel alloys with them, allowing for a nearly 1-to-1 replacement of standard ICEs with half the weight. Unfortunately, the cost of an XL ICE is equivalent to a Fusion engine while it "only" matches the performance of one, making the XL ICE's suitability on battlemechs or industrialmechs dubious at best. It's no surprise that the limited quantities of endo-steel produced was prioritized for Battlemech skeletons and LB-X autocannons.

The XL ICE, with only few examples produced, temporarily went extinct during the Succession Wars with the destruction of the orbital endo-steel factories. After the rediscovery of endo-steel, very limited examples of XL ICEs were produced, mostly as experimental designs. The first mass-produced examples of XL ICEs were produced by Clan Hell's Horses, followed by Clan Diamond Shark's XL ICE vehicles built for export.

A similar story exists with Fuel Cell engines, with the light-weight version taking advantage of the fuel cell's low operating temperatures to use light, high-strength titanium alloy frames to cut weight, and the XL fuel cells jumping into endo-steel structures. While not really used for Battlemechs, these do find a niche on high-end combat vehicles.
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Light ICE
Cost: (3125*Engine Rating*Unit Tonnage)/75 C-Bills
Tech Level: C/D-E-D-C
Weight: 1.5x Equivalent Fusion Engine
Crits:
Battlemech- 6 center torso, 2 side torsos (1 Clan)
Vehicle- 1 slot (0 Clan)

XL ICE
Cost: (5000*Engine Rating*Unit Tonnage)/75 C-Bills
Tech Level: D/F-X-F-E
Weight: 1x Equivalent Fusion Engine
Crits:
Battlemech- 6 center torso, 3 side torsos (2 Clan)
Vehicle- 2 slots (1 Clan)

Light FCE
Cost: (7500*Engine Rating*Unit Tonnage)/75 C-Bills
Tech Level: D/E-F-E-D
Weight: 0.9x Equivalent Fusion Engine
Crits:
Battlemech- 6 center torso, 2 side torsos (1 Clan)
Vehicle- 1 slot (0 Clan)
2 "free" heat sinks

XL FCE
Cost: (14000*Engine Rating*Unit Tonnage)/75 C-Bills
Tech Level: E/F-X-F-E
Weight: 0.6x Equivalent Fusion Engine
Crits:
Battlemech- 6 center torso, 3 side torsos (2 Clan)
Vehicle- 2 slots (1 Clan)
3 "free" heat sinks
ghostrider
08/10/19 01:32 AM
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Finally. Someone decided to use something other then the neutronium steel the developers have for ICEs. Endo steel, and ferrous Fiber being just a few that would make good materials.

An opinion here. I don't think the clans would have a less crit engine designed, as most clans dislike or hate vehicles, and this is most likely be put in them. Their opinions would be fusion for mechs.

Unless I missed it in the explanations, why the free heat sinks? To make it more acceptable in mechs?
Retry
08/10/19 02:04 AM
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Quote:
Finally. Someone decided to use something other then the neutronium steel the developers have for ICEs. Endo steel, and ferrous Fiber being just a few that would make good materials.

An opinion here. I don't think the clans would have a less crit engine designed, as most clans dislike or hate vehicles, and this is most likely be put in them. Their opinions would be fusion for mechs.

Unless I missed it in the explanations, why the free heat sinks? To make it more acceptable in mechs?


The clans aren't fans of vehicles in general, though the engines might see some use on industrial mechs too. I gave them that mostly to keep them consistent with the clan's more compact engines compared to the IS. Hell's Horses and Diamond Shark/Sea Fox are a bit more open minded with vehicles, so I'd bet they'd entertain the ideas. Hell's Horses, I'm guessing, would be happy to produce more effective vehicles with better ICEs or Fuel Cells so their fusion engines can be reserved for their mechs. Improved conventional vehicles with clan weapons would probably be good for making the Sea Foxes a quick buck.

Free heat sinks, the regular Fuel Cell engine by default had a free heat sink. I wanted to differentiate them from the ICEs to be a bit more different than "basically ICEs but Lighter", so I did that by marginally increasing the number of heat sinks slightly, so they can use a small number of energy weapons, like a medium laser or a small pulse laser.

I didn't have a fluff reason. I have a bit more knowledge on the theory behind ICEs so I was able to fluff those in, but I had no idea where to go with the fuel cells in terms of fluff.
Karagin
08/10/19 12:53 PM
72.176.171.47

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Yeah I was hoping back when all the talk was that they were coming out with lighter engines for vehicles that we would see new ICE stuff, instead they ignored that went with what the time was the cool new thing aka fuel cells, love it when the folks in charge want to do cool, but can't do it fully for some reason.

Same with the ICE engines for fighters...Turbines and such...but alas nope we didn't even get lighter conventional engines for those either.
Karagin

Given time and plenty of paper, a philosopher can prove anything.
ghostrider
08/10/19 12:53 PM
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The clans aren't fans of vehicles in general, though the engines might see some use on industrial mechs too.

This brings up an interesting question. Do the clans use industrial mechs?
I would think that would be against their beliefs. Mechs are war machines, and anyone driving one should be a warrior...

Though I do have a question on the slots for vehicles. Since the normal ICE doesn't take up any, is there a reason for doing so?
I am guessing that like the fusion xl, they are a bit more bulky.

As much as I love having the lighter weights, the fuel cells might be a little lighter then it should be. But this is just an observation.

I think this is a very solid plan.

Didn't see Karagins post, so adding this to it.
I don't understand why the IS wouldn't have looked for a lighter ICE, since they were supposedly limited on fusion engines, and vehicles are supposed to be over 4 to 1 with mechs.


Edited by ghostrider (08/10/19 12:55 PM)
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08/10/19 03:38 PM
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Quote:
This brings up an interesting question. Do the clans use industrial mechs?
I would think that would be against their beliefs. Mechs are war machines, and anyone driving one should be a warrior...

Though I do have a question on the slots for vehicles. Since the normal ICE doesn't take up any, is there a reason for doing so?
I am guessing that like the fusion xl, they are a bit more bulky.

As much as I love having the lighter weights, the fuel cells might be a little lighter then it should be. But this is just an observation.

I think this is a very solid plan.

Didn't see Karagins post, so adding this to it.
I don't understand why the IS wouldn't have looked for a lighter ICE, since they were supposedly limited on fusion engines, and vehicles are supposed to be over 4 to 1 with mechs.


I do think the Clans use IMs. Clan Goliath Scorpion built the Reptar and Arana militia mechs which are built on industrial chasses.

The Light and XL versions of these engines, like the fusion-based ones, are more bulky than the normal versions.

It's possible that I went a bit overboard with the XL Fuel Cell Engine.
ghostrider
08/11/19 12:50 PM
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A possible thought about the fuel cells.

Maybe base the amount of heat sinks on the size of the engine.
So 1 sink for 0-100
2 sinks for 101-200
3 sinks for 201-300
4 sinks for 301-400

The idea behind it is the larger engines would more likely have back up sinks to keep the engine cool as well as have the extra 'space' for them as well. Even the design could be considered 'air-cooled'.
Retry
08/11/19 08:37 PM
174.70.184.145

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Quote:
A possible thought about the fuel cells.

Maybe base the amount of heat sinks on the size of the engine.
So 1 sink for 0-100
2 sinks for 101-200
3 sinks for 201-300
4 sinks for 301-400

The idea behind it is the larger engines would more likely have back up sinks to keep the engine cool as well as have the extra 'space' for them as well. Even the design could be considered 'air-cooled'.


That could work, and in fact I'd probably prefer that way if I were making the Fuel Cell Engine vehicles from scratch. But since this indirectly changes the regular FCE it could have some effects on canon fuel cell designs.
AmaroqStarwind
12/30/19 05:09 PM
8.6.112.65

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XL internal combustion engines are bigger and more expensive than conventional internal combustion engines not because they are less space efficient, but because their designs are a lot more complicated and they have so many extra parts. This makes them more powerful for their given weight (and displacement) while also making them fuel efficient. (However, XL internal combustion engines aren't always bigger, depending on the technology rating.)

XL internal combustion engines are commonly used in racing and sport vehicles, and there are some more advanced variants which can also run on Hydrogen.

Thought I'd inject a little more real-life science into BattleTech~
Discord: Amaroq the Kitsune#1092
Telegram: @Lycanphoenix
MechEngine (Alpha) -- On Hiatus

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