Free-piston engine-pump unit

A free-piston engine-pump unit, comprising in combination:

• housing means defining therein first and second coaxially aligned and axially spaced bore means;
• first and second piston means slidably disposed in said first and second bore means respectively, said first and second piston means being fixedly interconnected for simultaneous reciprocating movement;
• each said piston means including a power piston coacting with the respective bore means to define a combustion chamber adjacent one end thereof, each said piston means also including a pumping piston fixed relative to the power piston and coacting with the respective bore means to define a pumping chamber adjacent the other end thereof;
• supply conduit means connected to said pumping chambers for supplying a low pressure working fluid thereto;
• discharge conduit means connected to said pumping chambers for permitting the pressurized working fluid to be discharged therefrom;
• means associated with each of said combustion chambers for supplying combustible fuel thereto;
• discharge passage means for discharging the exhaust gases from the combustion chambers;
• means defining a storage chamber within said housing means for storing therein pressurized air, and a pair of transfer passages providing communication between said storage chamber and said combustion chambers, each of said transfer passages providing communication between said storage chamber and a respective one of said combustion chambers, each said transfer passage communicating with the bore means defining the respective combustion chamber at a location whereby the discharge end of said transfer passage is alternately opened and closed responsive to the reciprocation of the respective power piston;
• and
• air pressurizing means associated with each of said power pistons for pressurizing air and then supplying same to said storage chamber;
• said pressurizing means as associated with each said power piston including an intermediate air supply chamber defined between the housing means and the respective piston means whereby air within the intermediate chamber is pressurized by the piston means during the power stroke thereof, an inlet passage communicating with said intermediate chamber to permit air to be supplied thereto during the compression stroke of the piston means, and a discharge passage providing communication between the intermediate chamber and the storage chamber to permit the pressurized air to flow from the intermediate chamber into said storage chamber.

A free-piston engine-pump unit, comprising in combination:

• housing means defining therein first and second coaxially aligned and axially spaced bore means;
• first and second piston means slidably disposed in said first and second bore means respectively, said first and second piston means being fixedly interconnected for simultaneous reciprocating movement;
• each said piston means including a power piston coacting with the respective bore means to define a combustion chamber adjacent one end thereof, each said piston means also including a pumping piston fixed relative to the power piston and coacting with the respective bore means to define a pumping chamber adjacent the other end thereof;
• supply conduit means connecting to said pumping chambers for supplying a working fluid thereto;
• discharge conduit means connected to said pumping chambers for permitting the working fluid to be discharged therefrom;
• inlet and discharge passage means connected to the combustion chambers for respectively supplying air thereto and discharging exhaust gases therefrom;
• control means for supplying pressurized working fluid into said pumping chambers to drivingly reciprocate said first and second piston means during start-up of the engine, said control means including first and second control conduits communicating with the pumping chambers of the first and second bore means respectively;
• said control means also including shiftable control valve means associated with said first and second control conduits for alternately and sequentially permitting the flow of high pressure working fluid to the pumping chambers to drivingly reciprocate the piston means back-and-forth until the engine is started, said control valve means being movable between a first end position wherein high pressure working fluid is supplied to one of the pumping chambers and a second end position wherein high pressure pumping fluid is supplied to the other pumping chamber;
• said control valve means including a slidable valve member which is linearly reciprocal between said first and second end positions, and said control valve means also including means cooperating with said valve member for positively urging same into one end position after the valve member has been moved a small distance away from the opposite end position, and vice versa;
• and
• mechanical means cooperating directly between said piston means and said control valve means for initiating automatic shifting of said control valve means between said first and second end positions in response to reciprocating movement of said piston means during start-up of the engine.

A free-piston engine-pump unit, comprising in combination:

• housing means defining therein first and second coaxially aligned and axially spaced bore means;
• first and second piston means slidably disposed in said first and second bore means respectively, said first and second piston means being fixedly interconnected for simultaneous reciprocating movement;
• each said piston means including a power piston coacting with the respective bore means to define a combustion chamber adjacent one end thereof, each said piston means also including a pumping piston fixed relative to the power piston and coacting with the respective bore means to define a pumping chamber adjacent the other end thereof;
• supply conduit means connecting to said pumping chambers for supplying a working fluid thereto;
• discharge conduit means connected to said pumping chambers for permitting the working fluid to be discharged therefrom;
• inlet and discharge passage means connected to the combustion chambers for respectively supplying air thereto and discharging exhaust gases therefrom;
• control means for supplying pressurized working fluid into said pumping chambers to drivingly reciprocate said first and second piston means during start-up of the engine, said control means including first and second control conduits communicating with the pumping chambers of the first and second bore means respectively;
• said control means also including shiftable control valve means associated with said first and second control conduits for alternately and sequentially permitting the flow of high pressure working fluid to the pumping chambers to drivingly reciprocate the piston means back-and-forth until the engine is started, said control valve means being movable between a first end position wherein high pressure working fluid is supplied to one of the pumping chambers and a second end position wherein high pressure working fluid is supplied to the other pumping chamber;
• said control valve means including a slidably shiftable sleevelike shuttle valve for controlling the flow of pressure fluid through said first and second conduits, and a toggle valve slidably supported in said sleevelike shuttle valve and shiftable axially with respect thereto, said shuttle and toggle valves being slidably reciprocal between said first and second end positions;
• said control valve means also including fluid chambers associated with the opposite ends of said toggle and shuttle valves, and porting means cooperating with said fluid chambers for supplying pressurized working fluid thereto to cause a pressure force to be imposed axially on the shuttle and toggle valves to assist in rapid shifting of the respective valve toward one of said end positions after it has been moved slightly away from the other end position;
• and
• mechanical means cooperating directly between said piston means and said control valve means for initiating automatic shifting of said control valve means between said first and second end positions in response to reciprocating movement of said piston means during start-up of the engine.

A free-piston engine-pump unit, comprising in combination:

• housing means defining therein first and second coaxially aligned and axially spaced bore means;
• first and second piston means slidably disposed in said first and second bore means respectively, said first and second piston means fixedly interconnected for simultaneous reciprocating movement;
• each said piston means including a power piston coacting with the respective bore means to define a combustion chamber adjacent one end thereof, each said piston means also including a pumping piston fixed relative to the power piston and coacting with the respective bore means to define a pumping chamber adjacent the other end thereof;
• supply conduit means connected to said pumping chambers for supplying a low-pressure working fluid thereto;
• discharge conduit means connected to said pumping chambers for permitting the pressurized working fluid to be discharged therefrom;
• inlet passage means for supplying air to the combustion chambers;
• discharge passage means for discharging the exhaust gases from the combustion chambers;
• and
• fuel injection means associated with each of said combustion chambers for supplying combustible fuel thereto, said fuel injector means including controlling means responsive to the working fluid for controlling the injection of fuel into the combustion chambers, said controlling means including a fuel flow-control piston shiftable between first and second positions by the working fluid to control the injection of fuel into the respective combustion chamber associated with the first and second bore means when the flow-control piston is in said first and second positions, respectively.

A free-piston engine-pump unit, comprising in combination:

• housing means defining therein first and second coaxially aligned and axially spaced bore means;
• first and second piston means slidably disposed in said first and second bore means respectively, said first and second piston means fixedly interconnected for simultaneous reciprocating movement;
• each said piston means including a power piston coacting with the respective bore means to define a combustion chamber adjacent one end thereof, each said piston means also including a pumping piston fixed relative to the power piston and coacting with the respective bore means to define a pumping chamber adjacent the other end thereof;
• supply conduit means connected to said pumping chambers for supplying a low-pressure working fluid thereto;
• discharge conduit means connected to said pumping chambers for permitting the pressurized working fluid to be discharged therefrom;
• inlet passage means for supplying air to the combustion chambers;
• discharge passage means for discharging the exhaust gasses from the combustion chambers;
• and
• fuel injection means associated with each of said combustion chambers for supplying combustible fuel thereto, said fuel injection means as associated with each said combustion chamber including nozzle means communicating with the respective combustion chamber and a movable fuel injection piston which is movable between a first position which closes off the nozzle means and a second position which permits flow of fuel through said nozzle means into the respective combustion chamber;
• said fuel injection means also including means defining a fuel supply chamber which communicates with said nozzle means for supplying fuel thereto, and a movable piston associated with said chamber for pressurizing the fuel therein;
• and
• actuating means for movably displacing said movable piston to thereby pressurize the fuel in said fuel supply chamber, said actuating means including an actuating member which cooperates directly between the respective power piston and the respective movable piston for causing movement of the movable piston to thereby pressurize the fuel in response to movement of the respective power piston during its compression stroke.