FI108069B - Cylinder cover for an engine for two fuels - Google Patents

Description

108069

Cylinder head for dual fuel engine

Divided by application 905494.

This invention relates to a cylinder head for dual fuel engines according to the preamble of claim 1.

5 Solid piston engines, which run on natural gas or other gaseous fuels, draw on ignition energy from a spark or a small amount of liquid auxiliary fuel (typically 5% of the total fuel) that has an adequate Sethane rating (typically diesel engine oil) and is injected. Auxiliary ignition engines serve 10 major parts of the industrial market as they overcome the spark ignition engines with their durability and power, and offer a complete transition to and from diesel during operation. These auxiliary-ignition engines are called "gas-diesel" or "bi-fuel" engines.

Typical bi-fuel engines are disclosed in U.S. Patents 15,4603,674 to Tamaka; 4,463,734 to Akeroyd; and 4,527,516 to Foster.

Control of engine emissions, particularly ΝΟχ emissions, has also become a concern, as shown in U.S. Patent No. 4,306,526 to Schaub et al; and No. 4,524,730 to Doell et al.

Although auxiliary ignition engines represent the most fuel efficient 20 power units in commercial use at present, these engines exhibit undesirable levels of emissions observed by analytical processes and visually yellow color. Extensive research at the research level has linked undesirable emission levels to the auxiliary liquid fuel and primary gaseous fuel competition of available oxygen. This competition for oxygen 25 favors gaseous fuel and starves the auxiliary fuel portion due to the high emissions of liquid fuel.

The object of the present invention is to control emissions, i.e. to control the yellow veil in the dual-fuel mode, as well as to broaden the control of other emissions in general.

Another object of the present invention is to reduce fuel consumption, improve power quality and extend the use of dual-fuel engines.

It is a further object of this invention to implement the above objects in a simple manner that is cost-effective, provides component durability and provides flexibility in the application of the invention.

These objects may be accomplished by the use of the present invention relating to an externally disposed liquid fuel injection element assembly 108069 which communicates with the main piston chamber, such element providing means for optimal ignition of the main chamber fuel, a lean gaseous fuel blend, simultaneously with maximum blast.

The cylinder head according to the invention is characterized in what is set forth in the characterizing part of claim 1.

Yet another object of the present invention is to provide an external independent spray element assembly that is readily utilized in post-installation situations as well as in the original hardware manufacture.

10 Other objects will be apparent to those skilled in the art from the following description and the accompanying drawings.

Figure 1 is a vertical sectional view in partial cross-section of a typical V-type, four-stroke engine model designed for high horse power continuous operation; Figure 2 is a vertical sectional view, partly in cross-section, of a similar lighter engine for back-up, offshore and marine applications, operating at slightly higher speeds;

Figure 3 is a schematic partial cross-sectional view of a combustion chamber combined with an improved injection element assembly incorporating the teachings of the present invention for use in a fuel gas operation mode and a standard injection nozzle for use in a full diesel mode;

Fig. 4 is an enlarged sectional view partly in section of the injection element of Fig. 3; Figure 5 is a sectional side view of the cylinder head assembly of the present invention;

Fig. 6 is a sectional bottom view taken along line 6-6 of Fig. 5 from the cylinder head with the lid removed;

Fig. 7 is a sectional view taken along line 7-7 of Fig. 6 showing the interior of the valve seat;

Figure 8 is a sectional view of a piston of the type contemplated in the present invention; and

Figure 9 is a perspective view of the cylinder head of the present invention.

Referring now to the drawings, in particular Figures 1 and 2, wherein like parts 35 are denoted by the same reference numerals, in Figure 1 a typical motor 10 of the type with which the present invention is intended includes 3 108069 pedestals 12 supporting a central body 14 mounted a plurality of cylinder blocks 16 spaced apart in a V-shape relative to said central body. Preferably, said pedestal, said central body, and said cylinder blocks are each made in one piece to achieve maximum rigidity and 5 constant orientation when combined. An axially disposed power crankshaft 18 is mounted on said central body and supported by suitable bearings along its entire length, and is connected by a connecting rod 20 to the pistons 22 disposed within the cylinder block 16. Each cylinder is closed at its upper end by a suitable cover 24, which normally includes two suction valves 10 26 and two exhaust valves 28, preferably the valve seats are of a recessed type and made of refractory material. The valves operate on suitably timed camshafts 30 engaging the cam wheels 32 and push rods 34 and actuated via rocker levers 36 or other suitable means by actuating the valves in a timed relationship. On the shaft of the cylinder head 24, a fuel injection nozzle 40 is generally disposed between the valves 26 and 28, as is usually the case with standard diesel engines. The injection nozzle 40 may also be a multi-hole nozzle. It also has an auxiliary valve 42 for starting a single-fuel diesel engine by moving the cylinders with compressed air until the piston compression force heats the air and the fuel mixture to a flash point when combustion occurs in normal operation. The various parts of the lighter-powered motor of Figure 2 are denoted by the same reference numerals, with the suffix "a" attached to them.

The bi-fuel engine of Figure 1 is a four-stroke LSVB engine and the bi-fuel engine of Figure 2 is a four-stroke KSV engine. Each is manufactured by the Cooper Industries Division. Dual fuel engines comprise a plurality of cylinders and are typically equipped with 12, 16 or 20 cylinders. LSVB and KSV motors have been modified by the injection element assembly 50 of the present invention (Figures 3 and 4).

The injection element according to the invention is suitable mainly for any type of large piston engine, whether fixed or movable.

. Large engines deliver the best value for money.

Referring now to Figures 3, 4, and 9, the invention is illustrated by a four-stroke engine cylinder, normally fueled with gaseous fuel, and having two injection element assemblies 50, which are ignited by a relatively small amount of liquid auxiliary fuel. The injection element self-ignition chamber 108069 is generally in the form of a segmented spheroidal paraboloid and typically has a volume of 1 to 5% of the volume of the main chamber 17 defined by the piston 22, cylinder head 24 and cylinder 16 walls at the top of the piston stroke. % of the master cylinder chamber volume 17, with the small engine at the top of the stroke. Such an injection element chamber 100 provides sufficient thermally and chemically active quality to ignite the lean content fuel of the main chamber 17. (Low combustion is an effective control mechanism for certain emissions that contain nitrogen oxides, especially from 10 gaseous fuels.)

Referring now to Figure 4, which is an enlarged view showing the element assembly 50 shown in Figure 3; assembly 50 generally comprises a tubular injection device body 60 having a fixed end portion 62 which is annularly lightened by discrete portions such as 64 and 68, further comprising a 15 annular shoulder 66 which provides a radial contact 67 for the purpose mentioned below. The free end of the solid portion 62 is provided with a substantially segmented spherical cavity 52 having a segment 51 preferably in the center of the sphere, i.e. being a hemispherical cavity and having a predetermined volume for a single motor to which it is to be connected. The cavity 52 is substantially symmetrical with respect to the axis of its tubular body 60 and communicates with the interior of the tubular body 60 through a angularly positioned passage 70 having a double submersible bore such as 72 and 74 and extending outwardly from the cavity 52 of the tubular body 60.

The geometry of the injection ignition chamber may be configured to include a shelf or pocket for controlling evaporation, agitation, or ignition.

The injection device 80 is screwed into a submerged bore 74, seated against a seal 82 disposed at the bottom of the submersible bore 72, and comprises a suitable tube or nozzle 84 extending into the passage 70. The injection device 80 30 is disposed slightly obliquely with respect to so that channel 70 enters cavity 52 slightly away from its tangential position for the purposes mentioned below.

The injector may be a multi-hole injector, a single-hole needle nozzle, or a nozzle whose model is dictated by the nature of ignitors other than 35 fuel oil.

5, 108069

The nozzle body 90 having a transversely extending recess and a bevelled end 92 has a narrow circumferential edge 94 for tight attachment, as will be described below, and comprises a segmented paraboloid cavity 93 compatible with the cavity 52 against its direct paraboloidal end 91 5 and at one end thereof. is a segment portion 95. The cavities 52 and 93 are generally connected to form a segmented spheroidal paraboloid chamber 100.

The exterior design of the downwardly extending nozzle body 90 is doubly bevelled to produce a frustoconical portion 96 and a conical 10 tip 98. The cavity 93 communicates with the cone 98 via a passageway 102 substantially tangential to the surface of the cavity 93 and generally perpendicular to the produced surface of the cone 98 . The passageway 102 is slightly raised away from the tangential line exiting the segmented spherical cavity formed at the end of the piston 22 when it is in the upper position of the stroke.

The nozzle body 90 is connected to the free end of the solid portion 62 by a welded or soldered fire 104 which fills the bevelled outer edges of their matching ends and end faces.

The cylinder head 24 is provided with an angled passageway 120, 20 having an axially located submerged seat 122 in a passageway 123 against which the nozzle end rim 94 is tightly engaged and an additional axially positioned passageway 124 for supporting and orienting the tubular body 60. The shoulder 66 may be an insertion fitting in the passageway 123 and preferably is made by suitable means, not shown in the drawings, to orient the passageway 102 relative to the access cylinder chamber 17. Likewise, the beveled portion 96 is rested on a sharp edge formed at the intersection of the channel 120 and the submerged seat 122.

The portion of the surface of the lid 24 associated with the channel 120 is shaped to form a bevelled groove 121. The nozzle channel 102 is directed toward the 30 conical recesses 121.

The fuel element 50 is a self-ignition fuel element - i.e., a fuel element having only a self ignition chamber 100 and without using sparking devices (i.e., spark plugs) or similar external ignition devices directly connected to the chamber 100.

Referring now to Figures 5-7 and 9, the cylinder head assembly 128 comprises a cover 129 which, when removed, exposes the orientation of the gas inlet or suction valves 6 108069 26 and the exhaust valves 28, with the injection ignition element assembly 50 disposed therebetween. Tempered rings 130 and 132 are mounted on valve seats 26 and 28.

As best seen in Figure 8, the pistons 22 used in the present invention preferably have a truncated spherical shape with an upper main surface 23. The piston may be a single piece casting or may be a two piece assembly provided with a steel cover 142 attached to the piston body 140. Suitable sealing rings 144 are provided as well as a bearing sleeve 146 for the piston pin not shown in the drawings. This truncated spherical piston cap 142 is a preferred model for all gas mode engines. In Figure 3, this preferred configuration is shown by the dashed line 23, while the solid line 23a depicts the piston cap, which is normally used in diesel engines.

Diesel mode is normally used to start dual-fuel engines 15, although the hemispherical piston heads are not the most effective variants of the diesel mode, but are accepted for their functions, namely, starting, heating and operating the engine in diesel mode. Even when the diesel mode is used for start-up, heating and full power, the liquid fuel injection element 20 is still in operation to keep it clean, although not necessary, but also to keep the injection element available when switching the fuel source to gaseous fuel.

This invention can also be used in a two-stroke engine as well as a four-stroke engine. The pistons 25 used in such motors generally have a diameter of 35.6 cm to 50.8 cm, whereby a single stroke is not vital. In the gaseous mode of operation, the injection ignition element is continuously lit. It is preferable to use a rich fuel mixture, which means a lower air to fuel ratio than 10: 1, i. the preferred ratio is 8: 1. The lean mixture would have an air ratio greater than 10: 1, approximately 12: 1.

30 The cetane number of a liquid fuel should be such that ignition occurs below a predetermined temperature and pressure.

The ignition value of the gas is such that it does not ignite below such a predetermined pressure alone, and therefore it is necessary to use a liquid fuel ignition element. The injection ignition element and its liquid fuel 35 are so designed that ignition occurs below the compression pressure of the materials in the upper chamber. While the chamber 100 108069 and the main piston chamber 17 are connected by a communication channel 102, hot pressurized gases enter the ignition element by a compression stroke of the piston 22 and are entrained in the chamber 100 by a tangential arrangement of the channel 102, the liquid fuel is angled air heat or ignites when it contacts the wall of chamber 100 and flows immediately both chemically and thermally out of channel 102 and ignites pressurized gaseous fuel in main chamber 17.

It is important to remember that the ignition element assembly 50 is external and not part of the cylinder chamber so that it can be used both as part of the original equipment and also available as a relatively simple retrofit for older single fuel engines or as a cure for other dual fuel engines.

The ignition element also produces a controlled fuel rich burn-15 in its combustion chamber. (Rich combustion is also an effective control mechanism for certain emissions containing nitrogen oxides and liquid fuels.)

The ignition element also permits the use of very small amounts of liquid fuels, since the liquid fuel can be tasked with simply igniting a controlled mixture of a combustible chamber which is highly flammable.

With the use of the present invention, the task of generating energy to ignite lean main combustion chamber fuel has shifted from direct injection of auxiliary liquid fuel into a controlled combustion chamber, where energy is generated mainly by gaseous fuel and is easily ignited by a small amount of liquid auxiliary fuel.

The flushing of the ignition element and the suction of gaseous fuel into the element is accomplished by variations in the pressure of the engine cylinder during expansion and compression events, but may be assisted by timed or untimely valves or openings using common or separate air and / or fuel sources not shown in these drawings.

Ignition of the injection ignition element is normally accomplished by injection of a quantity of fuel (ignition) having sufficient self-ignition capability to initiate combustion of 35 (cetane number) in an incinerated air / fuel mixture heated to a specific level by the cylinder s 8 108069. The ignition may also be initiated by contacting the igniter with the hot surface of the ignition element. Also, several types of external power supply heaters can be used.

Fuel oil with an acceptable Cetane number is currently available at a price 5 that is productive for the ignition medium, but other liquids and gases can be selected based on ignition capability, emission control properties, or economy. The small amount of ignition required by the ignition element makes it practical to use non-conventional fuel oil.

An important additional embodiment of the invention is that it allows the use of low engine compression ratios 10 to compensate for sensitive fuel (low octane). The ignition source (element) can be made more or less dependent on the heat produced by the compression and can therefore be tailored to operate in specific applications. Extensive flexibility is provided by the use of the heat sink assembly and external power supply.

The full power of the diesel engine in the context of the present invention is maintained using a conventional injection device 40 mounted on the cylinder head 24, which may be provided with cooling, as is well known, to maintain operational capability even during standby. During operation, the transition to full diesel mode or off 20 incorporates currently available standard procedures.

Other modifications and mechanical equivalents will be apparent to those skilled in the art from this specification and the appended claims, and are intended to read the claims as broadly as is within the skill of the art.

: 25

Claims (5)

9 108069 Cylinder cover for a dual fuel engine having a plurality of cylinders, each cylinder cover having at least 5 suction valves and at least one exhaust valve, characterized in that an ignition element (50) is provided on the cylinder cover (24) comprising an injection device (80). and an auto-ignition chamber (100) having a nozzle body (90), the cylinder head (24) having an oblique opening channel (120) engaging the nozzle body (90), a conical recess (121) extending from the channel member (120). ), and that a nozzle passage (102) is connected to the conical recess (121) at a predetermined angle to the upper inner part of the cylinder head (24). Cylinder cover according to claim 1, characterized by two channels (120) for mounting two ignition elements (50). Cylinder head according to Claim 1 or 2, characterized in that the cylinder head comprises a bore for attaching a fuel injection nozzle. Cylinder cover according to one of claims 1 to 3, characterized in that the cylinder cover (24) is arranged for a dual fuel engine and comprises at least two ignition element channels (120), two channels for suction valves (26), two channels for exhaust valves (28) and single-channel fuel injection nozzle. A cylinder head for two 25 fuel, gaseous and liquid fuel engine engines according to any one of claims 1 to 3 having a plurality of cylinders, wherein each cylinder head is operatively connected to two suction valves, two exhaust valves and a first liquid fuel injection nozzle, the fuel ignition element (50) is operably connected to a cylinder head (24), the ignition elements (50) operatively connected to a cylinder head at a position adjacent to the cylinder head circumference and secured between the suction valve (26) and the exhaust valve (28); a self-ignition chamber (100), and that the self-ignition nozzle channel (102) connects the self-ignition chamber 35 (100) at a predetermined angle with the upper inner portion of the cylinder head (24) and is oriented towards the cylinder ring a 10 108069 recess provided in the interior with a bevelled groove (121) tapering away from the ignition nozzle passage (102) towards the fuel injection nozzle (40). ,. 108069 11