Four cylinders eight pistons

[Old Farang]

A modern Knocker Commer!

A new opposed-piston diesel engine design yields more power and better efficiency from a smaller displacement, and is coming soon to a tank near you.

Four cylinders, eight pistons and no valves: Meet Cummins’ new 1000hp tank engine | CarAdvice (https://www.caradvice.com.au/871091/four-cylinders-eight-pistons-and-no-valves-meet-cummins-new-1000hp-tank-engine/)

[loanrangie]

Saw a video of these on YouTube , interesting design .

[trout1105]

At least you won't have to worry about warped heads or leaking head gaskets with this design[thumbsupbig]
Very clever [thumbsupbig]

[Old Farang]

Saw a video of these on YouTube , interesting design .
As mentioned in the article, the basic design is not new. What is new is the use of better materials, increased thermodynamics, much better air charging and scavenging, plus vastly improved fuel injection control and efficiency. It is interesting to note that they are using both turbo chargers(2) and a driven supercharger. The modular concept is also a modern innovation compared to historical designs.

In another life I worked on an old Knocker Commer. They were pretty much unique in the way that the piston stroke was connected to the crankshaft with bloody great "rocker arms". This new engine appears to use gears to connect to a common driveshaft. The Commer also used a Roots type blower, but no turbo charger.

[JDNSW]

The basic design seems to have first been used in WW1 U-boat engines, but has been used intermittently ever since in motor vehicles, trains, aeroplanes, ships etc. But it never sems to have displaced more conventional engines, so its advantages are perhaps overstated?

[Pedro_The_Swift]

or they are "overlooked" due to its one truly excellent design feature.. its size..

[loanrangie]

or they are "overlooked" due to its one truly excellent design feature.. its size..Yes height is a big issue for conventional car design but as a boxer it might work.

[jameshewitt95]

The basic design seems to have first been used in WW1 U-boat engines, but has been used intermittently ever since in motor vehicles, trains, aeroplanes, ships etc. But it never sems to have displaced more conventional engines, so its advantages are perhaps overstated?

Apparently even further back as the late 19th century for obviously a basic version. Engineering Explained on YouTube did a good video about someone else developing one. But they should give fantastic torque and should be way more stable in harsh conditions, which is probably why they were used in so many large armoured vehicles where stuff like size and overall fuel efficiency isn't the major concern.

I wonder what they've done to make 4 cylinders work, according to the paper the people developing the engine he describes show 3 cylinders allows for the highest efficiency of intake/exhaust cycles.

[rm_rocky]

Wonder if they are going to re-institute the Rolls-Royce 4-rotor diesel as well?

Forget Mazda, Rolls-Royce made a rotary and can you believe it was a diesel? | CarsGuide - OverSteer (https://www.carsguide.com.au/oversteer/forget-mazda-rolls-royce-made-a-rotary-and-can-you-believe-it-was-a-diesel-58311)