Description:A SYSTEM AND A METHOD FOR CONTROLLING TEMPERATURE OF CNG INJECTED IN AN ENGINE

TECHNICAL FIELD
[0001] The present subject matter described herein relates to a Compressed Natural Gas (CNG) injection system and method for an internal combustion engine. The present invention is particularly related to controlling the temperature of the CNG that is injected into an engine compartment.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present subject matter. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] CNG as fuel is stored in a high-pressure steel tank. The steel tanks are made mostly of heavy-walled steel or carbon-fiber/epoxy cylinders. Sometimes the CNG vehicles have reduced cargo space because of the design and placement of the tank. During the course of utilization, the pressure in the tank can vary from 200 bar to 10 bar.
[0004] The high-pressure steel tank is also fitted with a safety valve and a CNG filter. From this high-pressure tank, CNG goes to the CNG pressure regulator. The pressure regulator is generally tasked with controlling the CNG output pressure which can vary from 3 bar to 10 bar depending on the pressure setting of different Original Equipment Manufacturers (OEMs).
[0005] The CNG pressure keeps on varying according to the load capacities. It can vary between 200 bar to 3 bar in the pressure regulator. Thus, due to these huge changes in the pressure of CNG, the temperature also changes. When the pressure of the CNG gas drops, then the gas tends to expand, hence cooling it. This kind of gas expansion leads to sudden cooling which in case of natural gas can drop gas temperature from 40°C (in cylinder temp) to -30° C at the regulator outlet.
[0006] These temperature variations are sometimes dangerous for the engine. If the cooled CNG is allowed to go inside the engine it can lead to misfires and poor quality of combustion at the low driver demand (pedal).
[0007] Therefore in order to overcome the above-mentioned problem, the existing systems send engine coolant which is at 90°C to warm CNG pressure regulator, which in turn warms CNG outlet temperature. So, the CNG pressure regulator in itself works as a heat exchanger.
[0008] The existing systems do not have any control over the amount of heating and hence the CNG temperature at the outlet of the pressure regulator can vary depending on the tank pressure and the amount of CNG required by the engine.
[0009] It is therefore desirable to control the CNG outlet temperature at the pressure controller outlet at low, medium, and high loads.
OBJECTS OF THE DISCLOSURE
[0010] It forms an object of the present disclosure to overcome the aforementioned and other drawbacks/limitations in the existing solutions available in the form of related prior arts.
[0011] It is a primary object of the present disclosure is to control the CNG outlet temperature at the pressure controller outlet at low, medium, and high loads (all engine operating conditions).
[0012] It is another object of the present disclosure to provide a dynamic CNG temperature control at the pressure regulator outlet.
[0013] It is another object of the present disclosure to use an EMS-controlled variable flow coolant valve to the CNG pressure regulator.
[0014] These and other objects and advantages of the present subject matter will be apparent to a person skilled in the art after consideration of the following detailed description taken into consideration with accompanying drawings in which preferred embodiments of the present subject matter are illustrated.

SUMMARY
[0015] A solution to one or more drawbacks of existing technology and additional advantages are provided through the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be a part of the claimed disclosure.
[0016] The present disclosure provides a solution in the form of a system for controlling the temperature of Compressed Natural Gas (CNG) injected into an engine compartment. The system includes a vessel to store CNG, a pressure regulator connected with the vessel, wherein the pressure regulator controls the pressure of the CNG injected into the engine compartment, a variable opening valve connected between the supply line between the engine compartment and the pressure regulator, wherein the supply line is to provide a flow of coolant from the engine to the pressure regulator, and wherein the variable opening valve controls the flow of the coolant based as a function of at least one exhaust gas temperature, air-fuel ratio, and Exhaust Gas Recirculation (EGR).
[0017] In an aspect, the variable opening valve controls the flow of the coolant based on a function of at least one accelerator pedal position, engine speed, engine torque, manifold air temperature, and manifold air pressure.
[0018] In an aspect, an Electronic Control Unit (ECU) is connected with the variable opening valve, which controls the flow of coolant in the pressure regulator, which in turns control the output CNG temperature. The ECU controls the variable opening valve as the function of at least the one, accelerator pedal position, engine speed, engine torque/fuel, manifold air temperature-pressure, the exhaust gas temperature, the air-fuel ratio, and the EGR.
[0019] In an aspect, the method of controlling the temperature of CNG injected by a CNG injection system is disclosed. The method includes storing readings of accelerator pedal position, engine speed, engine torque/fuel, manifold air temperature-pressure, exhaust gas temperature, air-fuel ratio, and the EGR in an ECU and regulating a variable opening valve to regulate a flow of a coolant based as a function of at least one of stored accelerator pedal position, engine speed, engine torque/fuel, manifold air temperature-pressure, exhaust gas temperature, air-fuel ratio, and the EGR, wherein the variable opening valve is connected between the supply line between the engine compartment and the pressure regulator, wherein the supply line is to provide a flow of coolant from the engine to the pressure regulator.
[0020] In an aspect, the variable opening valve (104) controls the flow of the coolant based on a function of at least one of accelerator pedal position, engine speed, engine torque, manifold air temperature, and manifold air pressure.
[0021] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[0022] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting its scope, for the present disclosure may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference features and components. Some embodiments of system or methods or structure in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0023] Fig. 1 illustrates a block diagram of a system for controlling the temperature of Compressed Natural Gas (CNG) according to the present disclosure;
[0024] Fig. 2 illustrates a flowchart of a method for controlling the temperature of CNG according to the present disclosure.
[0025] The figures depict embodiments of the present subject matter for illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF INVENTION
[0026] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such detail as to communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0027] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0028] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0029] 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 example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0030] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and which are shown by way of illustration of specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.
[0031] Hereinafter, a description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary, a variety of optional components are described to illustrate the wide variety of possible embodiments of the present disclosure.
[0032] The present invention discloses a system and a method for controlling the temperature of CNG that is injected into an engine compartment. The present invention has a variable opening valve that works automatically into providing desirable temperature at a pressure regulator at various loads.
[0033] Referring to FIG. 1, shows the system (100) having direct fuel injection CNG stored as fuel in a vessel (102). The vessel (102) is fitted with a safety valve (106) and a CNG filter (107). From the vessel (102), the CNG goes to a pressure regulator (103), which controls the CNG output pressure. The output pressure varies from 3 bar to 10 bar depending on the pressure setting of different OEMs.
[0034] The present disclosure has a variable opening valve (104). Further, the variable opening valve (104) is connected to the supply line between the engine compartment (101) that is connected to an intake manifold (109) and the pressure regulator (103). The supply line is to provide a flow of coolant from the engine compartment (101) to the pressure regulator (103).
[0035] This variable opening valve (104) works in closed loop with the CNG rail T/P sensor (108) to provide desired CNG temperature at the pressure regulator (103).
[0036] The variable opening valve (104) also controls the flow of the coolant based on a function of at least one, accelerator pedal position, engine speed, engine torque/fuel, manifold air temperature-pressure, exhaust gas temperature, air-fuel ratio, and Exhaust Gas Recirculation (EGR).
[0037] An Electronic Control Unit (ECU) (105) is connected with the variable opening valve (104). The ECU (105) controls the variable opening valve (104) as the function of at least one accelerator pedal position, engine speed, engine torque/fuel, manifold air temperature-pressure, exhaust gas temperature, the air-fuel ratio, and the EGR.
[0038] The exhaust gas temperature is directly related to the component (exhaust valve, three-way catalytic converter) protection from excessive heat load, to remedy that fuel enrichment is done to reduce exhaust temperatures. By cooling CNG at the pressure regulator (103) the exhaust temperatures are reduced and fuel is enriched for component protection.
[0039] The EGR is used to lower throttling losses and reduce the NOx by reducing in the combustion temperature in engine compartment (101) but it can lead to higher THC (total hydrocarbon) and CO (carbon monoixde). By increasing the CNG temperature at the pressure regulator (103), the throttling losses are reduced, leading to lower EGR quantity requirements. On the other hand, the cooled CNG lower combustion temperatures and the NOx subsequently, thus leading to a lower EGR quantity requirement.
[0040] The exhaust gas temperature is directly related to the exhaust valve. It is related to the protection of components from excessive heat load. By cooling CNG at the pressure regulator (103) we reduce the exhaust temperatures and reduce/remove the need to do fuel enrichment for the component protection.
[0041] Finally, the functioning of the variable opening valve (104) is dependent on the engine load. At low load, the variable opening valve (104) functions in a way to give hot CNG as hot CNG has better combustion and lower throttling losses at low load.
[0042] At medium load, the temperature is controlled as to provide normal to cold CNG. The coolant released would be such as to provide the said temperature. This helps in lower combustion temperatures for lower NOx.
[0043] At high load, the temperature is controlled so as to provide cold CNG. It helps in lowering the combustion temperature which in turn gives lower NOx and lower component protection enrichment.
[0044] At WOT (Wide open throttle [peak power and torque]) condition, the temperature is controlled by the variable opening valve (104) so as to provide cold CNG to have lower NOx. Also, it will help in achieving lower component protection enrichmentt and higher volumetric efficiency.
[0045] The variable opening valve (104) also controls the flow of the coolant based on a function of at least one accelerator pedal position, engine speed, engine torque, manifold air temperature, manifold air pressure, exhaust gas temperature, the air-fuel ratio, and the EGR.
[0046] Referring to FIG. 2, the method (200) for controlling the temperature of Compressed Natural Gas (CNG) injected into the system (100) is disclosed.
[0047] The first step (201) is to store the reading of exhaust gas temperature, air-fuel ratio, and the EGR in an ECU (105). The ECU (105) works in a closed-loop with the CNG rail T/P sensor (108).
[0048] The second step (202) is to regulate a variable opening valve (104) to regulate a flow of a coolant based as a function of at least one stored accelerator pedal position, engine speed, engine torque/fuel, manifold air temperature-pressure, exhaust gas temperature, air-fuel ratio, and the EGR.
[0049] The variable opening valve (104) is connected to the supply line between the engine compartment (101) and the pressure regulator (103), wherein the supply line is to provide a flow of coolant from the engine compartment (101) to the pressure regulator (103).
TECHNICAL ADVANTAGES
[0050] With the help of the solution as proposed herein in the context of the present disclosure, the CNG gas temperature will be lowerd.
[0051] Lower CNG gas temperature will reduce exhaust temperature and subsequently any need for enrichment to protect catalyst.
[0052] Lower CNG gas temperature will reduce in cylinder combustion temperatures leading to lower NOx formation.
[0053] Lower CNG gas temperature will reduce inlet air charge temperature, which will increase the density of fresh Air + CNG mixture.
[0054] Lastly, a high density of air charge mixture has higher energy content which will lead to improved volumetric efficiency and eventually better engine performance.
[0055] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation, no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to disclosures containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. Also, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general, such construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general, such construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
[0056] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present disclosure contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the disclosure, and other dimensions or geometries are possible. Also, while a feature of the present disclosure may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present disclosure. The present disclosure also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that “consist essentially of” or “consist of” the recited feature. , Claims:We claim:
1. A system (100) for controlling the temperature of Compressed Natural Gas (CNG) injected into an engine compartment (101), the system (100) comprising:
a vessel (102) to store CNG;
a pressure regulator (103) connected with the vessel (102), wherein the pressure regulator (103) controls the pressure of the CNG injected into the engine compartment (101); and
a variable opening valve (104) connected to a supply line between the engine compartment (101) and the pressure regulator (103), wherein the supply line is to provide a flow of coolant from the engine to the pressure regulator (103), and wherein the variable opening valve (104) controls the flow of the coolant based as a function of at least one exhaust gas temperature, air-fuel ratio, and Exhaust Gas Recirculation (EGR).

2. The system (100) as claimed in claim 1, wherein the variable opening valve (104) controls the flow of the coolant based on a function of at least one of accelerator pedal position, engine speed, engine torque, manifold air temperature, and manifold air pressure.

3. The system (100) as claimed in claim 1, comprises an Electronic Control Unit (ECU) (105) connected with the variable opening valve (104), wherein the ECU (105) controls the opening variable opening valve as the function of at least the one accelerator pedal position, engine speed, engine torque/fuel, manifold air temperature-pressure, exhaust gas temperature, the air-fuel ratio, and the EGR.

4. A method (200) for controlling the temperature of Compressed Natural Gas (CNG) injected into a system (100), the method (200) comprising:
storing (201) reading of exhaust gas temperature, air-fuel ratio, and Exhaust Gas Recirculation (EGR) in an ECU (105);
regulating (202) a variable opening valve (104) to regulate a flow of a coolant based as a function of at least one of stored exhaust gas temperature, air-fuel ratio, and Exhaust Gas Recirculation (EGR),
wherein the variable opening valve (104) is connected to a supply line between the engine compartment (101) and the pressure regulator (103), wherein the supply line is to provide a flow of coolant from the engine to the pressure regulator (103).

5. The method (200) as claimed in claim 1, wherein the variable opening valve (104) controls the flow of the coolant based on a function of at least one of accelerator pedal position, engine speed, engine torque, manifold air temperature, and manifold air pressure.