Basics

This page is focused on pre-dev research on the Open Source Piston Engine
The Youtube Channel "Engineering Explained" has great information, and explanations on all sorts of engine related stuff, especially developing technologies

Emissions Contol

Diesel Exhaust Pollutants
Exhaust gas recirculation - reduces peak in-cylinder temperatures, reducing NOX ^[1]
DEF
Catalytic Converter

Electronic valves - eliminates need for camshaft and rockers, allowing higher simplicity, and 30% efficiency gain.
DIY campless - ^[2]
Camless engines are not yet available, outside of some large diesels. ^[3] -from 2016, is this still relevant, looking into this right now
- Seems to be one supercar coming out with it, and a company developing it for that car, may be in other designs?
  - The article on the obscenely expensive car
  - Freevalve
  - Seems to be a pnuematic system?
    - From their website:

"Previous fully variable valve actuation engines use either electro-magnetic or electro-hydraulic to open the poppet valves.

Instead of using these actuator types, Freevalve uses electro-hydraulic-pneumatic actuators combined with advanced sensor techniques.

As a result, Freevalve has overcome all of the typical challenges faced by other cam-less techniques."

Free piston engine - drives a working fluid directly, without crankshaft XMpP&sig=Ajz06elbtD8LeNBc7NGlPnsvD8o&hl=en&sa=X&ei=bRAUVcvXAcHlUraEhLAO&sqi=2&ved=0CF0Q6AEwDA#v=onepage&q=stelzer%20engine&f=false</ref>
Free piston engine linear generator (FPEG) - ^[4]
Hydrogen-powered linear generator is reportedly as efficient as fuel cells - ^[5]. Discusses linear generator configuration fired on both sides. Also discusses compression ignition of non-diesel fuel - via homogeneous (premixed) charge - (HCCI) . Peter Van Blarigan, Sandia Labs

Stelzer engine - 2 opposing combustion chambers with middle pumping chamber. ^[6]. Pertinent popular references -

- Uses pre-mixed fuel-air (via external/port injection, with ignition solely due to pressure + temperature increase)
- Main challenges seem to be
  - Making the precise "mix"
  - Keeping the engine temperature in the proper zone, as too hot causes premature ignition (knocking)