09-03-2011, 10:48 AM
SUBMITTED BY
Mr. KALPESH D. PATIL
[attachment=9837]
HYDRAULIC FREE PISTON ENGINES
ABSTRACT
The CHIRON is a hydraulic free piston engine developed by the Dutch companies NOAX and Innas. In the CHIRON the energy of the combustion process is almost directly converted into hydraulic energy. The CHIRON features a direct electronic control of the injection parameters, the flow and the compression ratio. The flow output is controlled by means of Pulse Pause Modulation of the piston frequency. The CHIRON is designed for application in common pressure rail systems. In these systems the hydraulic energy is supplied through a common rail. This paper describes the design of the CHIRON. Special attention will be paid on the specific characteristics of the CHIRON compared to conventional engines and pumps.
HYDRAULIC FREE PISTON ENGINES
A Free Piston Engine - almost everybody has some idea what it could be, but what are typical features of the free piston engines? There are two definitions, which are typical for all free piston engines:
• A combustion engine, which piston motion is not restricted by any mechanical linkages.
• The power is taken out by media, not by shaft
The reason why engineers have been interested in free piston engines since decades is the basic idea of a very simple engine. The simple design enables minimum amount of energy transformations from fuel energy into form, which is used by actuators.
The research in free piston engines has recently concentrated on hydraulic versions but some development in electric version has also been reported. Hydraulic free piston engine designs are possible and are divided into three categories according to the number and location of the pistons:
• Single piston
• Opposed piston
• Dual piston
The basic operation principle of each concept is similar i.e. the energy of the fuel is transformed into hydraulic energy by means of linearly moving piston assembly. Differences between the concepts are the number of combustion chambers and hydraulic pistons and compression stroke realization. The schematic drawings of the concepts are shown in figure on the next page.
The hydraulic free piston engine concepts, above: The single piston, middle: The opposed piston, below: The dual piston. Part numbers: 1: Combustion cylinder, 2: Compression cylinder, 3: Pump cylinder.
The combustion engine part is a two-stroke diesel engine because this kind of an engine requires power stroke once per each cycle. In order to achieve high combustion of the engine units under efficiency, diesel process with direct fuel injection is utilized. The power levels development are 15 – 50 kW, the total power is possible to raise by increasing the number of the engine units. The diameter of the combustion piston is 80 – 150 mm and operation frequency is up to 50 Hz.
FREE PISTON ENGINE Vs CONVENTIONAL ENGINES
Reasons, why there are research and development activities concerning the hydraulic free piston engine, are based on the benefits which could be achieved by the free piston concept. The HFPE(Hydraulic Free Piston Engine) has some fascinating advantages over the conventional crankshaft engine – hydraulic pump combination, CSEP(Crank Shaft Piston Engine)
• The power density of the HFPE is higher than the CSEP; this means less weight and less space required by the engine.
• Lower friction losses, because of fewer parts and piston has no side forces, which are induced by crank mechanisms.
• The last but not least is the price of the engine because of production costs, which are much lower in the HFPE because of simple design.
The efficiency of the HFPE is in the same level as in CSEP or even better. The lack of crank mechanism creates some disadvantages as well, the control system have to be more complicated than in the conventional engines. The compression ratio is indefinite and it depends on the energy balance of each stroke. The low emission level and efficient burning require controlled piston motion. On the other hand reliable compression ratio control enables the optimization of the compression ratio in different operation conditions, which is not possible with conventional engines. The other disadvantage of the HFPE is the lack of controllability of the output of the HFPE compared to conventional engine-pump combination because the pump is constant displacement or step wisely variable displacement pump.
Mr. KALPESH D. PATIL
[attachment=9837]
HYDRAULIC FREE PISTON ENGINES
ABSTRACT
The CHIRON is a hydraulic free piston engine developed by the Dutch companies NOAX and Innas. In the CHIRON the energy of the combustion process is almost directly converted into hydraulic energy. The CHIRON features a direct electronic control of the injection parameters, the flow and the compression ratio. The flow output is controlled by means of Pulse Pause Modulation of the piston frequency. The CHIRON is designed for application in common pressure rail systems. In these systems the hydraulic energy is supplied through a common rail. This paper describes the design of the CHIRON. Special attention will be paid on the specific characteristics of the CHIRON compared to conventional engines and pumps.
HYDRAULIC FREE PISTON ENGINES
A Free Piston Engine - almost everybody has some idea what it could be, but what are typical features of the free piston engines? There are two definitions, which are typical for all free piston engines:
• A combustion engine, which piston motion is not restricted by any mechanical linkages.
• The power is taken out by media, not by shaft
The reason why engineers have been interested in free piston engines since decades is the basic idea of a very simple engine. The simple design enables minimum amount of energy transformations from fuel energy into form, which is used by actuators.
The research in free piston engines has recently concentrated on hydraulic versions but some development in electric version has also been reported. Hydraulic free piston engine designs are possible and are divided into three categories according to the number and location of the pistons:
• Single piston
• Opposed piston
• Dual piston
The basic operation principle of each concept is similar i.e. the energy of the fuel is transformed into hydraulic energy by means of linearly moving piston assembly. Differences between the concepts are the number of combustion chambers and hydraulic pistons and compression stroke realization. The schematic drawings of the concepts are shown in figure on the next page.
The hydraulic free piston engine concepts, above: The single piston, middle: The opposed piston, below: The dual piston. Part numbers: 1: Combustion cylinder, 2: Compression cylinder, 3: Pump cylinder.
The combustion engine part is a two-stroke diesel engine because this kind of an engine requires power stroke once per each cycle. In order to achieve high combustion of the engine units under efficiency, diesel process with direct fuel injection is utilized. The power levels development are 15 – 50 kW, the total power is possible to raise by increasing the number of the engine units. The diameter of the combustion piston is 80 – 150 mm and operation frequency is up to 50 Hz.
FREE PISTON ENGINE Vs CONVENTIONAL ENGINES
Reasons, why there are research and development activities concerning the hydraulic free piston engine, are based on the benefits which could be achieved by the free piston concept. The HFPE(Hydraulic Free Piston Engine) has some fascinating advantages over the conventional crankshaft engine – hydraulic pump combination, CSEP(Crank Shaft Piston Engine)
• The power density of the HFPE is higher than the CSEP; this means less weight and less space required by the engine.
• Lower friction losses, because of fewer parts and piston has no side forces, which are induced by crank mechanisms.
• The last but not least is the price of the engine because of production costs, which are much lower in the HFPE because of simple design.
The efficiency of the HFPE is in the same level as in CSEP or even better. The lack of crank mechanism creates some disadvantages as well, the control system have to be more complicated than in the conventional engines. The compression ratio is indefinite and it depends on the energy balance of each stroke. The low emission level and efficient burning require controlled piston motion. On the other hand reliable compression ratio control enables the optimization of the compression ratio in different operation conditions, which is not possible with conventional engines. The other disadvantage of the HFPE is the lack of controllability of the output of the HFPE compared to conventional engine-pump combination because the pump is constant displacement or step wisely variable displacement pump.
