Cummins combat diesel engine - interesting design

[Trevor 57]

I know it is nearly 5 years old, but I am not sure if many have seen it

Flat 4cylinder, 1000bhp, about twice that in torque, two massive turbos, a supercharger, no valves, no cylinder heads, and it's a diesel.

It's got 8 pistons. And two crankshafts. Despite being a 4cylinder. Yes, it's an opposed piston engine, ie two pistons per cylinder facing each other.

This is a new Cummins engine designed for military use, and it's pretty badass.

It's 14.3ltr, so 1000bhp doesn't sound a lot for that capacity, but for a super low revving diesel that's intended to work for literally ever at full load, that's a lot- Most OEM 14ltr diesels make under 600bhp. And thanks to only 4cyl and no cylinder heads, it's relatively small too.

It's a 2stroke engine, so no valves, and the inlet and exhaust ports are opened by the pistons literally uncovering the holes on the sides of the cylinder walls- Much like ports on a rotary engine for anyone not used to 2stroke engines.

The turbos are twin Holset HE500 VGT turbos, which are 1000bhp+ capable units if pushed to their limits- Beasts.

The mix of 2stroke, supercharged, twin turbo, flat 4, and opposed piston, means this thing should sound pretty insane too.

Rather than me explain it all here, watch the video as the last parts are animations that shows exactly how the cranks are geared together and how the inlet and exhaust port setup works.

https://youtu.be/OfBB6uNkYKM

[roKWiz]

Originally Posted by Trevor 57

I know it is nearly 5 years old, but I am not sure if many have seen it

Flat 4cylinder, 1000bhp, about twice that in torque, two massive turbos, a supercharger, no valves, no cylinder heads, and it's a diesel.

It's got 8 pistons. And two crankshafts. Despite being a 4cylinder. Yes, it's an opposed piston engine, ie two pistons per cylinder facing each other.

This is a new Cummins engine designed for military use, and it's pretty badass.

It's 14.3ltr, so 1000bhp doesn't sound a lot for that capacity, but for a super low revving diesel that's intended to work for literally ever at full load, that's a lot- Most OEM 14ltr diesels make under 600bhp. And thanks to only 4cyl and no cylinder heads, it's relatively small too.

It's a 2stroke engine, so no valves, and the inlet and exhaust ports are opened by the pistons literally uncovering the holes on the sides of the cylinder walls- Much like ports on a rotary engine for anyone not used to 2stroke engines.

The turbos are twin Holset HE500 VGT turbos, which are 1000bhp+ capable units if pushed to their limits- Beasts.

The mix of 2stroke, supercharged, twin turbo, flat 4, and opposed piston, means this thing should sound pretty insane too.

Rather than me explain it all here, watch the video as the last parts are animations that shows exactly how the cranks are geared together and how the inlet and exhaust port setup works.

https://youtu.be/OfBB6uNkYKM

They brought that out at the same time they celebrated the VT903's 50th year of manufacture. (their other primary combat engine)

[GASWAGON]

Very impressive indeed.

Alot different to previous NT/N14 and Signature 600 Cummins!

[XR Martin]

There's a reason it's for military use - no emissions regulations.

[boss351290]

Originally Posted by XR Martin

There's a reason it's for military use - no emissions regulations.

When your fighting for life and someone is trying to kill you…. Do you care about emissions????

[XR Martin]

Originally Posted by boss351290

When your fighting for life and someone is trying to kill you…. Do you care about emissions????

I'm just saying the engine will never make it to civilian vehicle use due to emissions laws.
It's an impressive engine for off-road use.

[PooDog]

[Modern day Commer knocker motor lol

[Citroënbender]

Originally Posted by boss351290

When your fighting for life and someone is trying to kill you…. Do you care about emissions????

[jpd80]

A lot of the yank military runs on a common jet fuel, not diesel

[Trevor 57]

Originally Posted by jpd80

A lot of the yank military runs on a common jet fuel, not diesel

So clean kero?

[jpd80]

Originally Posted by Trevor 57

So clean kero?

JP-8 is similar to commercial aviation fuel with some extra additives
Most of the tanks have turbines and Diesel engines can run on it too.

[burnz]

Originally Posted by Trevor 57

So clean kero?

i don't think it matters trev, it's still oil.
slightly less energy per liter.

[burnz]

Napier Deltic train engine.

https://en.wikipedia.org/wiki/Napier_Deltic

https://www.youtube.com/watch?v=jPUy9a3xi4w

[Bossxr8]

Originally Posted by jpd80

A lot of the yank military runs on a common jet fuel, not diesel

The engine in the M1 Abrams can pretty much run on anything resembling a type of fuel.

[roKWiz]

Originally Posted by burnz

Napier Deltic train engine.

https://en.wikipedia.org/wiki/Napier_Deltic

https://www.youtube.com/watch?v=jPUy9a3xi4w

One of best sounding diesels. imo.

[jpd80]

Originally Posted by Bossxr8

The engine in the M1 Abrams can pretty much run on anything resembling a type of fuel.

Because it’s a gas turbine…

[jpd80]

Originally Posted by roKWiz

One of best sounding diesels. imo.

Nice engine design but it used to oil up badly

[Bossxr8]

Originally Posted by jpd80

Because it’s a gas turbine…

Correct. Supposed to be a massive fuel guzzler as well, with a fairly limited range for a tank. The supply lines would need to be well in check to keep them fuelled up.

[roKWiz]

Originally Posted by Bossxr8

Correct. Supposed to be a massive fuel guzzler as well, with a fairly limited range for a tank. The supply lines would need to be well in check to keep them fuelled up.

Exactly the same reason both Kenworth in the 50's and Ford in the 60's gave up on gas turbines.

Quoted from trucksplanet site......."Gas turbine powered Kenworth had crossed the United States from north to south, and then worked briefly in commercial traffic plying on the western coast, between Seattle and Los Angeles, the tests, alas, failed. First of all, the trip lasted five or six hours longer than with conventional diesel engine: a gas turbine powered truck was accelerated slowly, heavily smoked, while squeezing the clutch pedal was a real torture (despite the fact that even the conventional old "Americans" have vere tight clutch). But the main problem was that the consumption of turbine was equaled a mile per gallon, or 235 l/100 km!"

Makes the Cummins look like a fuel pincher.

[Bossxr8]

Originally Posted by roKWiz

Exactly the same reason both Kenworth in the 50's and Ford in the 60's gave up on gas turbines.

Quoted from trucksplanet site......."Gas turbine powered Kenworth had crossed the United States from north to south, and then worked briefly in commercial traffic plying on the western coast, between Seattle and Los Angeles, the tests, alas, failed. First of all, the trip lasted five or six hours longer than with conventional diesel engine: a gas turbine powered truck was accelerated slowly, heavily smoked, while squeezing the clutch pedal was a real torture (despite the fact that even the conventional old "Americans" have vere tight clutch). But the main problem was that the consumption of turbine was equaled a mile per gallon, or 235 l/100 km!"

Makes the Cummins look like a fuel pincher.

I’m pretty sure Chrysler was the furtherest down the road with gas turbines. I think they actually leased some out to the public? But yeah the economy was poor, and i think they generated a lot of heat as well, so they eventually gave up.

[Franco Cozzo]