Steam Engine Design/Free Piston Steam Hydraulic - Revision history

ChuckH: /* Features */

2011-12-30T19:04:11Z

Features

← Older revision		Revision as of 19:04, 30 December 2011
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	Some features of this design concept		Some features of this design concept
	* This is a '''variable stroke''', '''variable intake cutoff''', '''variable exhaust cutoff''' machine, so it should be able to operate efficiently over a fairly wide range of operating conditions		* This is a '''variable stroke''', '''variable intake cutoff''', '''variable exhaust cutoff''' machine, so it should be able to operate efficiently over a fairly wide range of operating conditions
			* The intake, exhaust, and hydraulic valve timings are controlled by an "intelligent" algorithm in a microcontroller
	* There is no flywheel required or desirable		* There is no flywheel required or desirable
	* The piston returns to TDC (ironically, Top Dead Center is downwards because of the inverted design) by gravity		* The piston returns to TDC (ironically, Top Dead Center is downwards because of the inverted design) by gravity
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	* At a certain point in the piston up-stroke the hydraulic valve will close, decelerating the piston rapidly and delivering its energy into the hydraulic system		* At a certain point in the piston up-stroke the hydraulic valve will close, decelerating the piston rapidly and delivering its energy into the hydraulic system
	* At very light loads, the engine can operate on an intermittent basis, doing one or two cycles then waiting at TDC.		* At very light loads, the engine can operate on an intermittent basis, doing one or two cycles then waiting at TDC.

	== Simulation Model ==		== Simulation Model ==
	Simulation model using freely available [http://www.linear.com/designtools/software/#LTspice LTSpice IV] simulation program. LTSpice is intended for electrical schematics, so it labels everything as volts and amps. However the simulation math doesn't care whether we are voltage or pressure or mass.		Simulation model using freely available [http://www.linear.com/designtools/software/#LTspice LTSpice IV] simulation program. LTSpice is intended for electrical schematics, so it labels everything as volts and amps. However the simulation math doesn't care whether we are voltage or pressure or mass.

ChuckH at 19:02, 30 December 2011

2011-12-30T19:02:19Z

← Older revision		Revision as of 19:02, 30 December 2011
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	See some other free-piston references [[Steam_Engine_Design/Suggestions#Crankless_.28Free_Piston.29_Hydraulic \| here]] and [[Steam_Powered_Hydraulic_Pump \| here]].		See some other free-piston references [[Steam_Engine_Design/Suggestions#Crankless_.28Free_Piston.29_Hydraulic \| here]] and [[Steam_Powered_Hydraulic_Pump \| here]].
			== Features ==

	----		Some features of this design concept
			* This is a '''variable stroke''', '''variable intake cutoff''', '''variable exhaust cutoff''' machine, so it should be able to operate efficiently over a fairly wide range of operating conditions
			* There is no flywheel required or desirable
			* The piston returns to TDC (ironically, Top Dead Center is downwards because of the inverted design) by gravity
			* Gravity return limits the maximum operating speed to a few hundred rpm
			* The amount of energy the falling piston mass carries as it approaches TDC is directly proportional to the stroke length; the stroke length is determined on a cycle-by-cycle basis by the hydraulic valve timing
			* The energy of the falling piston mass is delivered to two places
			** Recompressing the steam<br>Recompressing the steam to match the inlet pressure eliminates one type of energy loss at the intake valve
			** Compressing the rebound springs<br>The rebound springs are not theoretically essential but provide some extra flexibility in engine control timing<br>Energy stored in the rebound springs is returned to the piston's upstroke so this is not an energy loss
			* The piston will typically accelerate upwards ballistically (with no hydraulic load, because the free-flow hydraulic valve is open) during the beginning of the stroke
			* At a certain point in the piston up-stroke the hydraulic valve will close, decelerating the piston rapidly and delivering its energy into the hydraulic system
			* At very light loads, the engine can operate on an intermittent basis, doing one or two cycles then waiting at TDC.
			== Simulation Model ==
	Simulation model using freely available [http://www.linear.com/designtools/software/#LTspice LTSpice IV] simulation program. LTSpice is intended for electrical schematics, so it labels everything as volts and amps. However the simulation math doesn't care whether we are voltage or pressure or mass.		Simulation model using freely available [http://www.linear.com/designtools/software/#LTspice LTSpice IV] simulation program. LTSpice is intended for electrical schematics, so it labels everything as volts and amps. However the simulation math doesn't care whether we are voltage or pressure or mass.

ChuckH: /* Free Piston Steam-Hydraulic Engine */

2011-11-25T19:41:50Z