WO1993010343A1 - Procede d'exploitation d'un moteur a pistons libres, et moteur a pistons libres associe - Google Patents

Procede d'exploitation d'un moteur a pistons libres, et moteur a pistons libres associe Download PDF

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Publication number
WO1993010343A1
WO1993010343A1 PCT/NL1992/000210 NL9200210W WO9310343A1 WO 1993010343 A1 WO1993010343 A1 WO 1993010343A1 NL 9200210 W NL9200210 W NL 9200210W WO 9310343 A1 WO9310343 A1 WO 9310343A1
Authority
WO
WIPO (PCT)
Prior art keywords
piston
fuel
air
free
combustion
Prior art date
Application number
PCT/NL1992/000210
Other languages
English (en)
Inventor
Peter Augustinus Johannes Achten
Theodorus Gerhardus Potma
Original Assignee
Innas B.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Innas B.V. filed Critical Innas B.V.
Publication of WO1993010343A1 publication Critical patent/WO1993010343A1/fr

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B71/00—Free-piston engines; Engines without rotary main shaft
    • F02B71/02—Starting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B71/00—Free-piston engines; Engines without rotary main shaft
    • F02B71/04—Adaptations of such engines for special use; Combinations of such engines with apparatus driven thereby
    • F02B71/045—Adaptations of such engines for special use; Combinations of such engines with apparatus driven thereby with hydrostatic transmission
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition

Definitions

  • the present invention relates to a method of operating a free-piston engine according to the diesel principle, wherein a combustion room in a cylinder is reduced by displacing a piston thereby compressing air supplied to the cylinder, fuel being injected into the combustion room allowing the mixture of air and fuel to ignite by spontaneous combustion and to expand for returning the piston.
  • the object of the invention is to provide a method of operating a free-piston engine according to the diesel principle realizing an improved efficiency.
  • the method according to the invention is characterized in that the main fuel injection is started at such a moment that more than half of the mixture of fuel and air is combusted only after the piston has started to return.
  • the optimum moment of injection of the fuel for obtaining a high efficiency is late, even so late that at least half and preferably the greater part of the mixture of fuel and air is only combusted after the top dead centre of the piston, that is after the piston has already started to return.
  • the combustion pressure in the cylinder will remain low and may have a value, for example, which is similar to the compression end pressure.
  • the fuel should of course still be injected so early that the mixture gets the change to ignite by spontaneous combustion.
  • the method according to the invention has not only a favourable effect on efficiency, but also the content of contaminants in the exhaust fumes is lowe than in the conventional prior art methods.
  • the low maximum combustion pressure within the cylinder further has a favourable influence on the noise level of the engine.
  • the most optimum combustion conditions are obtained at a certain ignition moment, wherein there is supplied an amount of energ to the compressed mixture which is set within narrow limits.
  • the invention also provides for means enabling the regulation of the amount of supplied energy with an accuracy better than 5 %. For this purpose there are used a.o. pressure sensors within the compression pressure accumulator, and the starting point of the compression stroke is accurately fixed.
  • Fig. 1 is a very schematic longitudinal sectional view of a free-piston engine including a scheme of the hydraulic parts thereof.
  • Fig. 2 and 3 are a p-V-diagram and p-t-diagram, respectively, belonging to a method of the prior art.
  • Fig. 4 and 5 are a p-V-diagram and p-t-diagram, respectively, belonging to an exemplary embodiment of the method according to the present invention.
  • Fig. 1 schematically shows an embodiment of a free- piston engine in which the method according to the invention may be used.
  • This free-piston engine includes a cylinder 1 in which a piston 2 may reciprocate in order to enlarge and reduce a combustion room 3 on one side of the piston which will be referred to later on.
  • a rod 4 having plunger elements 5 and 6 is formed on the piston 3, the plunger element 5 mainly serves for displacing the piston 2 to the top dead centre, that is in a direction to reduce the combustion room 3 for compressing combustion air introduced therein, by means of an hydraulic compression device 7.
  • the plunger element 6 serves for converting mechanical energy delivered to the piston 2 and rod 4 af er combustion in the combustion room 3, into hydraulic energy, which takes place by means of a hydraulic working device 8. Since the compression device 7 and the working device 8 do not form part of the present invention, they will not be further elucidated. It may be noted, however, that there are arranged pressure sensors 16 within the compression pressure accumulator 15 of the compression device 7 in order to enable an accurate regulation of the compression energy supplied to the piston 2.
  • an air inlet channel 9 including a back pressure valve 10 communicates to the part of the cylinder 1 below the piston 2, while a connecting or scavenging channel 11 can ensure that air from the space below the piston 2 can arrive in the combustion room 3 when the piston 2 moves to the bottom dead centre.
  • combustion gasses may be removed from the combustion room 3.
  • a sensor 17 is provided for sensing the bottom dead centre of the piston 2.
  • an injector 14 adapted to inject liquid fuel, such as diesel oil, into the combustion room 3 by atomizing it.
  • Control means 18 control the start and the duration of the fuel injection.
  • the present invention is concerned with the injection of the fuel by this injector 14, and in particular with the time it happens.
  • Figs. 2 and 3 illustrate by means of a p-V and p-t- diagram the progress of the pressure within the combustion space 3 when fuel is injected in the conventional manner.
  • the volume decreases and the pressure increases, firstly linear and then after ignition of the mixture in a very rapid progressive manner to a high pressure, whereafter the pressure decreases again according to the upper curve in the diagram by increase of the volume as a result of the expansion stroke of the piston 2. It is shown that the pressure within the combustion room 3 rises almost up to 100 bar.
  • the method according to the invention does not only lead to an improvement in the efficiency of the combustion (judged from the area between the curves going back and forth in the p-V-diagrams and the area below the curve in the p-t- diagrams) , but also to a lower NOx-emission and a lower noise level of the internal combustion engine. It is noted that if one drafts a graph of the induced efficiency as a function of the injection time and the supplied compression energy, the position of the optimum curve is influenced by the variable factors as the ambient temperature, the engine temperature, the amount of fuel injected, the quality of the fuel (cetane rating) , the stroke frequency, the pre-injection, and engine characteristics as piston weight, stroke/diameter ratio, piston displacement and charging pressure.
  • the invention is not restricted to the embodiment shown in the drawing and described above by way of example, which may be varied in different manners within the scope of the invention.
  • the invention may also be used in free-piston engines having two opposed pistons and the combustion room hence being limited on two sides by a piston.
  • the ignition of the fuel-air mixture may start before the piston is in its top dead centre, but at least half and preferably the greater part (for example 80 to 90 %) of the combustion will still occur after the top dead centre of the piston. Also in that case the favourable effect on efficiency and emission described above will occur.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

Procédé d'exploitation d'un moteur Diesel à pistons libres. Selon le procédé, le volume d'une chambre de combustion dans un cylindre est réduit par le déplacement d'un piston de manière à comprimer l'air introduit dans le cylindre. Un carburant est injecté dans la chambre de combustion afin de permettre la combustion spontanée du mélange air-carburant, et l'expansion de celui-ci afin d'entraîner la course de retour du piston. L'injection principale du carburant s'amorce à l'instant où plus de la moitié du mélange air-carburant a brûlé, et après que le piston ait entamé sa course de retour. On a également prévu un moteur à pistons libres fonctionnant conformément audit procédé.
PCT/NL1992/000210 1991-11-19 1992-11-19 Procede d'exploitation d'un moteur a pistons libres, et moteur a pistons libres associe WO1993010343A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL9101932 1991-11-19
NL9101932A NL9101932A (nl) 1991-11-19 1991-11-19 Werkwijze voor het laten werken van een vrije-zuigermotor; en vrije-zuigermotor die werkt volgens deze werkwijze.

Publications (1)

Publication Number Publication Date
WO1993010343A1 true WO1993010343A1 (fr) 1993-05-27

Family

ID=19859936

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NL1992/000210 WO1993010343A1 (fr) 1991-11-19 1992-11-19 Procede d'exploitation d'un moteur a pistons libres, et moteur a pistons libres associe

Country Status (2)

Country Link
NL (1) NL9101932A (fr)
WO (1) WO1993010343A1 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997035104A1 (fr) * 1996-03-20 1997-09-25 Starodetko Evgeny Alexandrovic Moteur a pistons libres et son mode de fonctionnement
WO1999025969A1 (fr) * 1997-11-19 1999-05-27 Caterpillar Inc. Moteur a deux temps dote d'une monosoupape integree a un injecteur de carburant
US6152091A (en) * 1999-02-22 2000-11-28 Caterpillar Inc. Method of operating a free piston internal combustion engine with a variable pressure hydraulic fluid output
US6158401A (en) * 1999-02-24 2000-12-12 Caterpillar Inc. Method of operating a free piston internal combustion engine with pulse compression
US6269783B1 (en) 1999-02-22 2001-08-07 Caterpillar Inc. Free piston internal combustion engine with pulse compression
CN101907017A (zh) * 2009-06-02 2010-12-08 杨焕利 液压能量转换器
CN109736957A (zh) * 2018-12-20 2019-05-10 南京理工大学 一种自由活塞发动机启动过程控制方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1220163A (fr) * 1958-01-23 1960-05-23 Stewart Warner Corp Moteur à pistons libres à synchronisation automatique du mouvement des pistons
NL7416078A (nl) * 1974-12-10 1976-06-14 Kooten Bv V Heiblok en een werkwijze voor het regelen daarvan.
US4599861A (en) * 1985-05-13 1986-07-15 Beaumont Richard W Internal combustion hydraulic engine

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1220163A (fr) * 1958-01-23 1960-05-23 Stewart Warner Corp Moteur à pistons libres à synchronisation automatique du mouvement des pistons
NL7416078A (nl) * 1974-12-10 1976-06-14 Kooten Bv V Heiblok en een werkwijze voor het regelen daarvan.
US4599861A (en) * 1985-05-13 1986-07-15 Beaumont Richard W Internal combustion hydraulic engine

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
H.R.RICARDO 'THE HIGH SPEED INTERNAL COMBUSTION ENGINE' 1 January 1953 , BLACKIE & SON LTD , LONDON AND GLASGOW *
J.J.BROEZE 'COMBUSTION IN PISTON ENGINES' 1 July 1963 , H.STAM N.V. , HAARLEM *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997035104A1 (fr) * 1996-03-20 1997-09-25 Starodetko Evgeny Alexandrovic Moteur a pistons libres et son mode de fonctionnement
WO1999025969A1 (fr) * 1997-11-19 1999-05-27 Caterpillar Inc. Moteur a deux temps dote d'une monosoupape integree a un injecteur de carburant
US6152091A (en) * 1999-02-22 2000-11-28 Caterpillar Inc. Method of operating a free piston internal combustion engine with a variable pressure hydraulic fluid output
US6269783B1 (en) 1999-02-22 2001-08-07 Caterpillar Inc. Free piston internal combustion engine with pulse compression
US6463895B2 (en) 1999-02-22 2002-10-15 Caterpillar Inc Free piston internal combustion engine with pulse compression
US6158401A (en) * 1999-02-24 2000-12-12 Caterpillar Inc. Method of operating a free piston internal combustion engine with pulse compression
CN101907017A (zh) * 2009-06-02 2010-12-08 杨焕利 液压能量转换器
CN109736957A (zh) * 2018-12-20 2019-05-10 南京理工大学 一种自由活塞发动机启动过程控制方法
CN109736957B (zh) * 2018-12-20 2021-09-03 南京理工大学 一种自由活塞发动机启动过程控制方法

Also Published As

Publication number Publication date
NL9101932A (nl) 1993-06-16

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