Presented by:
Mr. Kalpesh D.Patil

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HYDRAULIC FREE PISTON ENGINES
INTRODUCTION:
 The core of this engine is a combustion piston directly coupled to a hydraulic plunger. The piston is not connected to any mechanism but is free to move within the limitations of the cylinders. In this way the energy of the combustion process is almost directly converted into hydraulic energy. Compared to a conventional combination of a pump and a combustion engine, the number of parts is reduced to approximately 40%.
 Fig: CHIRON Hydraulic Free Piston engine.
WORKING PRINCIPLE
FUEL INJECTION
 For the Chiron a HEUI injector of Caterpillar Inc. was chosen. The control of the injector is integrated in the control module of the Chiron. The HEUI injector is hydraulically actuated and the energy is taken from the hydraulic energy delivered by the hydraulic pump part.
CONTROL
 The control of the Chiron is realized by means of sensors, actuators and electronics. Synchronization of piston movement and fuel injection can only be realized by electronic control. Two simple and robust inductive sensors are used to determine the position of the plunger.
DIGITALLY CONTROLLED VALVE
COMBUSTION
 The combustion part of the Chiron is a two-stroke naturally aspired diesel engine with a simple port controlled scavenge process (loop scavenging). The backside of the combustion piston is used as the scavenge pump. This results in a compact and cost-effective construction.
COOLING
 The combustion cylinder and cylinder head are liquid cooled. The cooling channels are integrated in the castings. The liquid is supplied at the bottom side, cooling the exhaust ports first. Water can be used as cooling medium.
CHARACTERISTICS
 EFFICIENCY
This graph of efficiency (%) Vs Flow (ltr/min) compares the CHIRON with the regular Diesel engine.
APPLICATIONS
CONCLUSION
 These engines allow a better optimization towards lower fuel consumption and reduced exhaust emissions than the current drive lines. Leading companies in the fields of construction machines and hydraulic components now continue the development of these Free Piston Engines.