Fuel Injection with Swirl Spray Patterns in Opposed
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(19) TZZ Z_ZZ_T (11) EP 2 901 005 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.: of the grant of the patent: F02M 61/18 (2006.01) F02M 61/16 (2006.01) 15.11.2017 Bulletin 2017/46 F02B 23/06 (2006.01) F02B 25/08 (2006.01) F02B 75/28 (2006.01) F01B 7/14 (2006.01) (21) Application number: 13771692.4 (86) International application number: (22) Date of filing: 18.09.2013 PCT/US2013/060429 (87) International publication number: WO 2014/052126 (03.04.2014 Gazette 2014/14) (54) FUEL INJECTION WITH SWIRL SPRAY PATTERNS IN OPPOSED-PISTON ENGINES KRAFTSTOFFEINSPRITZUNG MIT WIRBELSPRÜHMUSTERN IN MOTOREN MIT ENTGEGENGESETZTEN KOLBEN INJECTION DE CARBURANT AVEC FORMES DE JET À TOURBILLON DANS DES MOTEURS À PISTONS OPPOSÉS (84) Designated Contracting States: • KLYZA, Clark, A. AL AT BE BG CH CY CZ DE DK EE ES FI FR GB San Diego, CA 92110 (US) GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO • REDON, Fabien, G. PL PT RO RS SE SI SK SM TR San Diego, CA 92124 (US) (30) Priority: 25.09.2012 US 201261705561 P (74) Representative: Hanna Moore + Curley Garryard House (43) Date of publication of application: 25/26 Earlsfort Terrace 05.08.2015 Bulletin 2015/32 Dublin 2, D02 PX51 (IE) (73) Proprietor: Achates Power, Inc. (56) References cited: San Diego, CA 92121 (US) JP-A- 2009 138 718 US-A- 5 042 441 US-A1- 2012 073 541 (72) Inventors: • ABANI, Neerav San Diego, CA 92130 (US) Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 2 901 005 B1 Printed by Jouve, 75001 PARIS (FR) 1 EP 2 901 005 B1 2 Description [0006] To reduce the heat transfer across the pistons and walls, the spray angle of the multiple holes is re- RELATED APPLICATIONS duced. However, this leads to interaction of opposing spray plumes that concentrates fuel-vapor, entrained air, [0001] This application contains subject matter related 5 and some hot combustion products around the central to thesubject matter ofUS patentapplication 13/136,954, region of the combustion chamber. This inhibits air/fuel filed 08/15/2011, for "Fuel Injection Spray Patterns for mixing, which results in increasing burn time. Opposed Piston Engines", and published as US[0007] To achieve both faster burn and reduced heat 2012/0073541 A1 on 03/29/2012. transfer to the cylinder bore and piston surfaces in op- [0002] This application contains subject matter related 10 posed piston operation, it is desirable that fuel injection to thesubject matter ofUS patentapplication 13/066,589, spray patterns minimize interaction of sprays (both from filed 04/18/2011, for "Combustion Chamber Construc- the same injector and opposite injectors), minimize the tions for Opposed Piston Engines", and published as US transfer of heat to the piston and cylinder bore surfaces, 2011/0271932 A1 on 11/10/2011. and encourage faster fuel/air mixing. 15 [0008] The present state of the art is also represented BACKGROUND by US 5,042,441 A and JP 2009/138718 A. [0003] The field is fuel injection in opposed-piston en- SUMMARY gines in which a combustion chamber is defined between end surfaces of pistons disposed in opposition in the bore 20 [0009] The present invention provides a fuel injection of a ported cylinder. More particularly, the field includes system for an opposed-piston engine, and methods of direct fuel injection through the side of a cylinder into the operating same, in accordance with claims which follow. combustion chamber of an opposed-piston engine. Embodiments of the invention provide a fuel injection [0004] Fuel injection is an important component of spray pattern in which the individual spray plumes have combustion in diesel engines and is one of the processes 25 both radial and tangential components with respect to an that affect the efficiency with which the diesel engine op- injection axis adds a swirl component to a spray pattern erates. It is desirable to manage fuel injection so as to of fuel directly injected into the combustion chamber of maximize the heat produced by combustion while mini- an opposed piston engine. As compared to a spray pat- mizing transfer of the heat of combustion to engine com- tern that has only a radial component, a spray pattern ponents such as cylinder bore and piston surfaces. An 30 with a swirl component minimizes the interaction of in- opposed piston engine typically employs two fuel injec- jected fuel sprays so as to provide a faster burn time. At tors that inject fuel in opposing directions along a diam- the same time, the addition of a tangential component eter of the cylinder. See, for example, the fuel injection provides additional distance for a spray plume to travel constructions described and illustrated in commonly- without encountering piston surfaces, the cylinder bore, owned US publication 2012/0073541 A1. 35 and/oropposing spray plumes, which reducesheat trans- [0005] A diesel injector typically includes a nozzle with fer across the piston and cylinder walls while promoting a plurality of holes through which fuel is injected. The faster air/fuel mixing. holes are arranged radially with respect to an axis of the [0010] In some aspects, the swirl spray pattern is di- injector. Injection through multiple holes produces a rectly injected into the combustion chamber through a spray pattern constituted of one or more plumes that40 cylinder sidewall. In some aspects, the swirl spray pattern project radially outward from the injector axis. Typically has an injection axis that is aligned with a longitudinal a plume is represented by a vector that forms an angle axis of the combustion chamber; in some of these as- (a "spray angle") in a respective plane shared with the pects, the injection axis is transverse to the longitudinal injector axis. A wider spray angle results in a plume being axis of the cylinder. injected at a higher angle away from the injector axis. 45 [0011] In other aspects, direct side injection includes This is desirable because the fuel of each individual injection of swirl spray patterns in opposing radial direc- plume burns in the presence of air independently of the tions of a cylinder bore into a combustion chamber of an other plumes. There is less interaction of individual opposed-piston engine wherein charge air has a com- plumes and hence, a faster burn time. However, in an plex, turbulent motion. Preferably, the air motion includes opposed piston engine, a wider spray angle also pushes 50 swirl and tumble components. the plume and hence the flame closer to the cylinder bore [0012] A fuel injector having a nozzle with a multi-hole and piston surfaces, resulting in combustion near those construction that produces a swirl spray pattern is here- surfaces. This can result in excessive heat transfer into inafter referred to as a multiple-hole swirl injector (MHSI). the cylinder liner and piston walls. Such heat transfer While conventional multiple-hole injector nozzle con- results in a loss of power; and a higher heat transfer loss 55 structions are designed such that a plane can pass means lower indicated thermal efficiency of the engine. through a vector representing an individual plume and Heat transfer can be reduced by directing the plumes the injector axis, a MHSI produces a swirl spray pattern away from the cylinder bore surface. characterized by one or more spray plumes whose vec- 2 3 EP 2 901 005 B1 4 tors do not lie in a plane that contains the injector axis. FIGS. 13, 14, 15, 16, and 17 are schematic sectional views of a nozzle construction for a multiple-hole BRIEF DESCRIPTION OF THE DRAWINGS swirl injector taken on a central plane that illustrate construction effects resulting from various combina- [0013] 5 tions of primary and secondary angles. FIGS. 1A and 1B are schematic diagrams that illus- DETAILED DESCRIPTION OF THE PREFERRED EM- trate the effect of adding a swirl component to a fuel BODIMENTS spray pattern with respect to the injector axis of an 8-hole injector. 10 [0014] In the following description, "fuel" is any fuel that can be used in an opposed-piston engine. The fuel may FIG. 2A is a schematic diagram that illustrates a plu- be a relatively homogeneous composition, or a blend. rality of 3-hole groups of an 18-hole injector having For example, the fuel may be diesel fuel or any other fuel a multiple-hole swirl injection pattern: FIG. 2B is an ignitable by compression ignition. Further, the descrip- enlarged schematic view showing a swirl spray pat- 15 tions contemplate ignition resulting from compression of tern of a three-hole group. an air/fuel mixture; however it may be desirable to provide additional mechanisms, such as glow plugs, to assist FIGS. 3A and 3B illustrate a cylinder of an opposed compression ignition. The descriptions contemplate in- piston engine in which fuel injectors are positioned jection of fuel into a compressed gas in a combustion for direct side injection of fuel into a combustion20 chamber when opposed pistons are at or near TDC lo- chamber formed when the opposed pistons in the cations. The gas is preferably pressurized ambient air; cylinder are near top dead center positions. however, it may include other components such as ex- haust gases or other diluents.