Evaluating the feasibility of a large displacement 750 RPM powerplant engine.
Naturally aspirated, CR=16.5 for producer-gas (appr 50..55 Nm / liter of displacement equivalent to 4300 Watt on shaft, 4kWe on generator).
Gensets with similar engines usually achieve 50-80 kWe / ton of weight (the more common configuration is 1500 RPM engines with traditional crankshaft and connection-rods).
Wet cylinder liners - displacement
- bore = appr. 220 mm
- the centrifugal-metalcasting shop specified max 270 mm outer dia for the cyl liner, preferrably max 260 mm if possible
- stroke=300..350 mm
- the centrifugal-metalcasting shop specified max 540 mm cylinder liner length
- ~ 13.3 liter / cylinder
2 * 6 cylinders (160 liter total, appr 640 kWe). 2*4 (106 liter) would be another option.
Double roller
- connecting rods have 2 bearings, very hard to lubricate (and conrods stress the piston rings).
- horizontal twin-piston (align their pair) with double roller "swashplate" design (not wobble-plate!) is
Rollers are 110..160 kN radial force depending on bore. (bearing for this is appr 150 mm OD, and 3kg)
See
- http://www.eleg.hu/tiki/tiki-index.php?page=Axi%C3%A1lDugatty%C3%BAsMotor
- See 40 sec in [video] in this kinder engine
- note the rollers, and the oil-grooves in the twin-piston
Valves, valve-seat
- traditional
Preferrably compatible with an engine family (Caterpillar, Cummins, whatever...).
Any valve family where d > 48 mm ?
Camplate
1 camplate at each end of the engine
- with 4 fingers (different radius, of course) on each camplate
- odd cylinders: 1 finger for 2 intake valves + 1 finger for 2 exhaust valves
- even cylinders: 1 finger for 2 intake valves + 1 finger for 2 exhaust valves. Even cylinder fires 360+60 degrees after the neighbor odd cylinder. (for more even running)
- Using rockers (of different length) to actuate the lifters.
Lifters
Mechanical or hydraulic ?
- any suggestions for hydraulic lifters ?
Head
- traditional.
- 4 valves per cylinder + preferrably 2 sparkplugs per cyl
- Separate head for each cylinder
Oil pump
- electrical oil pump can be switched on before cranking.
- provision for chain-driven mechanical oil pump. One-way valves allow the 2 pumps to be connected in parallel
Coolant pump
- electrical coolant pump
- provision for chain-driven mechanical coolant pump. One-way valves allow the 2 pumps to be connected in parallel