- #1
rethunk
- 11
- 0
I imagine most of you know of the 6-stroke Crower engine. By adding a 2 more cycles when steam is injected, it is attempting to recover mechanical work from waste heat from cylinder walls and crown.
One of supposed advantages of it is it doesn't need block cooling due to the steam cycle taking out the heat.
But all sorts of problems occur with steam hitting hot metal and mixing with exhaust residue. Plus, although there is a power stroke for one third of the cycle rather than one quarter with standard Otto, the steam-power stroke is only a fraction of the energy of the combustion stroke.
Additionally there is the (true) Atkinson cycle which has a longer piston throw for the combustion and exhaust stages than induction and compression stages.
I envisage a positively pressurised key-way four-fifths of the way down the cylinder wall that only becomes exposed on the longer throw of the combustion/exhaust strokes. During the exhaust stroke this can force in a supercharged airflow to push the burnt air out of the exhaust port earlier and a millisecond later introduce 'wet' air into the chamber for cooling and increased exhaust exit velocity. - recovered by a std turbo.
This has the advantage of keeping the gases in the cylinder 'insulated' from the wet air behind, that can cool the internals of the engine and allow a mechanical recovery of that heat through pressurising the turbo.
The engine should be lighter than a standard config. (no cooling system - lighter block/no radiator, etc) plus unlike the Crower engine there is almost no opportunity for the water to become polluted by exhaust residue, whereby it can acidify and cause damage.
Not nearly as much water would be injected and it would be in suspension (air) and would heat less rapidly, reducing risk to the components. The trick would be to stream the increased velocity exhaust gases through the turbo as normal but spin-out (via separator) the heavier (and re-condensed) steam for repeating the cycle.
One of supposed advantages of it is it doesn't need block cooling due to the steam cycle taking out the heat.
But all sorts of problems occur with steam hitting hot metal and mixing with exhaust residue. Plus, although there is a power stroke for one third of the cycle rather than one quarter with standard Otto, the steam-power stroke is only a fraction of the energy of the combustion stroke.
Additionally there is the (true) Atkinson cycle which has a longer piston throw for the combustion and exhaust stages than induction and compression stages.
I envisage a positively pressurised key-way four-fifths of the way down the cylinder wall that only becomes exposed on the longer throw of the combustion/exhaust strokes. During the exhaust stroke this can force in a supercharged airflow to push the burnt air out of the exhaust port earlier and a millisecond later introduce 'wet' air into the chamber for cooling and increased exhaust exit velocity. - recovered by a std turbo.
This has the advantage of keeping the gases in the cylinder 'insulated' from the wet air behind, that can cool the internals of the engine and allow a mechanical recovery of that heat through pressurising the turbo.
The engine should be lighter than a standard config. (no cooling system - lighter block/no radiator, etc) plus unlike the Crower engine there is almost no opportunity for the water to become polluted by exhaust residue, whereby it can acidify and cause damage.
Not nearly as much water would be injected and it would be in suspension (air) and would heat less rapidly, reducing risk to the components. The trick would be to stream the increased velocity exhaust gases through the turbo as normal but spin-out (via separator) the heavier (and re-condensed) steam for repeating the cycle.