Patent ID: 12188422

DETAILED DESCRIPTION

The detailed description set forth below provides information and examples of the disclosed technology with sufficient detail to enable those skilled in the art to practice the disclosure.

FIG.1illustrates an example of timing for a first fuel (hydrogen) injection1, an ignition2and a second fuel (hydrogen) injection3for an internal combustion engine operating according to a four-stroke cycle with an intake stroke starting at −360° (crank angel degrees, CAD), a compression stroke starting at −180°, an expansion stroke starting at 0°, and an exhaust stroke starting at 180°.

As shown inFIG.1, the first injection1has a relatively short duration and is in this example carried out at around −110° CAD. The ignition2is carried out at around −20° CAD and the second injection is initiated at around −10° CAD. The second injection2involves injection of a second amount of fuel that may be 10 times larger than a first amount of fuel injected in the first injection1. A duration of the second fuel injection is around 30° CAD.

FIGS.2-4show a part of an internal combustion engine system20comprising a piston4arranged to reciprocate in a cylinder5between a bottom dead center (BDC, not shown) and a top dead center (TDC, roughly as positioned inFIG.3). With reference toFIG.1, the piston is in the TDC position at −360°, 0° and 360° CAD. The piston4is via a connection rod (not shown) connected to a crank shaft (not shown) in line with a conventional internal combustion engine.

FIGS.2-4further show a main combustion chamber6arranged at an end portion of the cylinder5so that an upper surface7of the piston4defines a lower side of the main combustion chamber6. An inlet valve8and an exhaust valve9are arranged to regulate flow of air and exhaust gas to and from the main combustion chamber6via corresponding ducts10,11.

A pre-combustion chamber12is arranged in association with the main combustion chamber6. In this case the pre-combustion chamber12is located partly outside of the main combustions chamber6. The pre-combustion chamber12, or rather a wall defining the pre-combustion chamber12, is provided with a plurality of orifices13allowing fluid communication between the pre-combustion chamber12and the main combustion chamber6.

A fuel injector14is arranged to inject hydrogen fuel into the pre-combustion chamber12. The injector14is arranged so that a fuel outlet thereof is enclosed by the pre-combustion chamber12.

An igniter15, such as a spark plug or similar, is arranged to ignite a fuel-air mix present in the pre-combustion chamber.

FIG.2shows the situation when the first injection1just has been performed by the injector14so that the first amount of fuel1A just has been injected into the pre-combustion chamber12. The piston4is here positioned at, for instance, −100° CAD and is moving towards the TDC in the compression stroke. Air in the main combustion chamber6is compressed and forced through the orifices13into the pre-combustion chamber12and mixes therein with the first amount of fuel1A.

FIG.3shows the situation when the igniter15just has been activated so as to ignite the fuel-air mix in the pre-combustion chamber12. Temperature and pressure increases rapidly in the pre-combustion chamber12and burning fuel-mix is forced through the orifices13into the main combustion chamber6(indicated by small jets16). The piston4is here close to TDC.

FIG.4shows the situation when the second injection3just has been performed by the injector14so that the second (larger) amount of fuel3A just has been injected into the pre-combustion chamber12. Because the second amount of fuel3A is sufficiently large and has a sufficiently high pressure, it is forced further through the orifices13into the main combustion chamber6(indicated by large jets17). Some portion of the second amount of fuel3A may start burning (i.e., reacting with oxygen in the air) inside the pre-combustion chamber12but a large portion will push burning fuel in front of itself into the main combustion chamber6and start burning only after having entered the main combustion chamber6. InFIG.4, the piston4has passed the TDC and has started moving towards the BDC.

The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including” when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and/or groups thereof.

It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.

Relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the disclosure being set forth in the following claims.