Operating parameters for digital engine?

[EdDanzer]

I have constructed a 1 cylinder linear engine designed to pump hydraulic oil to charge accumulators and run a hydraulic motor. Could anyone define operating parameters equal to 250 rpms. for a 3 ½” (80mm) bore engine. The valves are electric over hydraulic control, an accumulator is used as the flywheel, and piston travel is electric over hydraulic control. The stroke is variable up to 6” (150mm), with an 8:1 compression ratio (this can be varied later). The stroke position is provided by a linear transducer, and I will be using a programmable controller to command the cycles of operation. Timing of valves, and spark in relation to piston location will need to be in milliseconds (.001 seconds being the shortest time interval with the controller I have) instead of degrees.

 

[werdnaid]

Well I'm not really sure of what you are doing. In my head, I see a big cylinder with a piston in it. On one end of the cylinder is a spark plug & ports for getting fuel in & burned gas out. On the other end is ports from an oil resoirvoir & accumulator. As far as the spark firing the distance, or time in mili seconds BTDC would vary according stroke & valve timing & head design. I wonder if it would work, because the flywheel energy to push the piston back up is the pressure & volume that was sent to the accumulator & can be sent back. Can you be 100% effiencent in volume?

 

[EdDanzer]

It works just not well yet.
If I knew how to include a photo or CAD image you could look at the actual prototype, but a description will have to do for now. The head is a from a Z24 Nissan truck, and is attached to a cast iron barrel. A Chevy piston pinned to the control cylinder slides inside the barrel. This control cylinder when driven by the accumulator acts as a flywheel moving the piston through intake, compression, and exhaust. When the fuel, provided by a Ford port fuel injector is ignited, the combustion pressure turns the cylinder into a piston pump. Hydraulic valves control how the pumped oil power is used.
The first control cylinder I tried was too large in bore. I was firing it on starting fluid using toggle switches for control. The thing fired but didn’t have enough force to push the piston down much.
I’m in the process of redesigning the control cylinder with the goal of extracting 5hp at 2000 psi when the engine completes 60 firings per minute.