Serial / Parallel Twin-Turbo
Fig. 1a shows the serial/parallel connection scheme for a twin-turbo set-up (top view). The turbos are a pair from Mitsubishi 3000GT and all tubing is 1.75” except when joined together into 2.5” for the inputs and outputs of the system. The control is done my two triple butterfly valve assemblies, one for the intake (cold, top half of picture) and one for the exhaust (hot, bottom half of picture). The three butterfly valves are mounted on the same shaft and the center valve is phased opposite of the outer valves, meaning that the canter valve is closed when the two outer valves are open (and visa versa) and the two outer valves are synchronous.
This is a 4-port system, meaning that there is only one input and one output for both intake and exhaust. For a V-engine and dual exhaust the air/gas has to be merged before entering and split up after exiting the system.
The fresh (atmospheric) air comes in at the intake at the upper left hand corner of the picture and the compressed air (from both serial and parallel connection) exits at the top right.
The exhaust enters at the bottom left of the center of the picture and exits to the catalytic converters, muffler etc. to the lower right after passing through the turbines either serially or in parallel.
Fig. 1b shows a different view of the system (exhaust side view).
The control of the two triple air-valves has not been settled. At this point it is not clear to me if on/off actuation is a necessity or intermediate settings (part serial / part parallel) are acceptable.
At this point there appears to be a number of options:
1) External actuation via a stepper motor, servo motor or relay controlled by the engine management system.
2) External actuation via a pressure differential actuator and controlled by a pressure difference taken at appropriate places.
3) Internal actuation by offsetting the plates of the appropriate butterfly valve(s) and controlled by the pressure difference and flow across the offset plates and a return spring for the reverse action.
For any of the above schemes the exhaust and intake section can be controlled independently, making possible any combination of serial/parallel connection of the intake and exhaust.
Fig. 1c shows another view of the system (bottom view).
It should be noted that this is an early iteration of the layout, so more compact and better adapted to current engine layout (headers, down-pipe exhaust and induction system) should be possible.
The system as shown will fit in a 23” x 16” x 18” box.
Fig. 2a shows the triple butterfly valves system with the center valve phased opposite the outer valves. The butterfly plates are not offset in this rendition
Fig. 2b shows the triple air-valve assembly. At this point the same design is used for both intake and exhaust. The intake valve may at a later point be made from less expensive materials. No external actuator is shown.