Description:Field of Invention
[001] The invention relates to Diesel Internal Combustion (IC) engine. It more particularly relates to method of operating the Diesel Internal Combustion (IC) engine so as to reduce formation of pollutants.
Background of the Invention
[002] With implementation of new pollution control standard for IC engines there has arisen need to reduce tailpipe emission of pollutants. With particular reference to Diesel Internal Combustion (IC) engines, the major pollutants that are normally emitted are Nitrogen Oxides (NOX) and Particulate Matter (PM) (commonly identified as soot). It is known that the conventional methods of reducing formation of NOX end up increasing the formation of PM, whereas if PM emissions are reduced using known methods the formation of NOX increases. Given that current emission standards demand reduction in tailpipe emission of both NOX and PM, there exists a need for better method of operating the Diesel IC engines so that the new tailpipe emission standards can be meet.
[003] Another issue that is particularly important as far as our country is concerned is the need for reducing emissions without adversely affecting the mileage of the Diesel IC Engine, because if the newly developed method achieves reduction in NOX and PM formation at the cost of mileage, the end users may not be able to afford running vehicles adhering to new emission standards. There exists a need to ensure that the solution implemented for reducing NOX and PM emissions do not cause a reduction in the mileage of the vehicle.
[004] The improvement would have to be achieved without addition of any new component in pre-existing vehicles as it may not be possible to achieve the addition of a component without extensive modification of the vehicle design which again may not be possible in every case or if at all possible, in most instances, it may end up raising the cost of the vehicle. Therefore, it is an objective of the present invention to provide a method of reducing formation of pollutants during the operation of Diesel IC Engine.
[005] It is another objective of the present invention to provide a method of reducing formation of pollutants during operation of Diesel IC Engines that does not adversely affect the mileage of the Diesel IC Engine powered vehicles.
[006] It is still another objective of the present invention to provide a method of reducing formation of pollutants during operation of Diesel IC Engines that can be implemented without addition of any new component in the vehicles.
[007] It is yet another objective of the present invention to provide a method of reducing formation of pollutants during operation of Diesel IC Engines that can be implemented in pre-existing vehicles without requiring extensive modification.
Summary of the Invention
[008] An embodiment of the invention achieving the stated objective, that is a method for reduction of soot formation in Diesel IC Engine, that can be implemented in Diesel IC Engine vehicle comprising of, electrically controlled fuel injectors, and an engine management system. As per the method for reduction of soot formation in Diesel IC Engine, as a first step, two separate fuel injections, identifiable as pilot fuel injections are made before the piston reaches the top dead centre during the initiation of the combustion stage of the Diesel IC Engine; as a second step, one fuel injection, identifiable as a main fuel injection is made when the piston reaches the top dead centre during the combustion stage of the Diesel IC Engine; as a third step, one fuel injection, identifiable as an after-fuel injection, is made after the piston starts moving back to the bottom dead centre during the combustion stage of the Diesel IC Engine; and as a fourth step, two separate fuel injections, identifiable as post fuel injections, are made after the after-fuel injection, when the piston is travelling towards the bottom dead centre during the combustion stage of the Diesel IC Engine.
Brief Description of Drawings
[009] The present invention is illustrated in the accompanying drawings that contain references numerals for indicating its various parts. The description of the present invention would therefore be better understood with reference to accompanying diagrams, wherein
[0010] Figure 1 discloses a bar graph representing fuel injections to piston position relation as per the method of reduction of soot formation in Diesel IC Engines.
[0011] Figure 2 discloses a images of piston inside combustion chamber that explain the manner in which the method of reduction of soot formation in Diesel IC Engine work.
[0012] Figure 3 discloses graph indicating the change in PM (soot) and NOX formation when the method of reduction of soot formation in Diesel IC Engine is implemented.
[0013] Figure 4 discloses the schematic view of the setup that allows for measurement of PM and NOX emissions where the method of reduction of soot formation in Diesel IC Engine is implemented.
Detailed Description of the Invention
[0014] Referring to the figure 1, method for reduction of soot formation in Diesel IC engine, that can be implemented in Diesel IC Engine vehicle comprising of, electrically controlled fuel injectors, and an engine management system. The electronically controlled fuel injectors are having solenoid inside fuel injectors that are electronically connected to the engine management system, which would thereby allow them to be controlled in accordance with the method disclosed hereinafter. In other words, operation of the electrically controlled fuel injectors must be controllable by the engine management system. The Diesel IC Engine setup implementing the proposed method can be provided with features enabling exhaust gas recirculation thereby magnifying the positive effects of its implementation in pre-existing vehicles.
[0015] As per the method for reduction of soot formation in Diesel IC engine, as represented by Fig. 1, as a first step, one or two separate fuel injections, identifiable as pilot fuel injections are made before the piston reaches the top dead centre during the initiation of the combustion stage of the Diesel IC Engine. The two pilot injections last for equal time intervals and inject equal quantities of Diesel fuel as the piston is travelling to the top dead centre during the initiation of Diesel Engine’s combustion stage, when the crank angle is between 25 to 5 degrees. Even though two pilot injections tend to give smoother power generation curve, the number can be reduced to below two depending upon the performance requirement as per the application.
[0016] As a second step, one fuel injection, identifiable as a main fuel injection is made when the piston reaches the top dead centre during the combustion stage of the Diesel IC Engine. The main injection lasting for larger time interval than the pilot fuel injections and injecting larger fuel quantity than the pilot fuel injections is made when the piston has reached the top dead centre during the combustion stage, when the crank angle is between 5 to 0 degrees.
[0017] As a third step, one fuel injection, identifiable as an after-fuel injection, is made after the piston starts moving back to the bottom dead centre during the combustion stage of the Diesel IC Engine. The after-fuel injection lasting smaller for time interval than either the pilot and main fuel injections and injecting smaller fuel quantities than the pilot and main fuel injections is made after the piston has started moving towards the bottom dead centre during the combustion stage, when the crank angle is between -1 to -5 degrees.
[0018] As a fourth step, two separate fuel injections, identifiable as post fuel injections, are made after the after-fuel injection, when the piston is travelling towards the bottom dead centre during the combustion stage of the Diesel IC Engine. The two post injections are made as when required to maintain the exhaust gas temperatures for meeting Nox conversion efficiency in Selective Catalyst reduction (SCR) or during Diesel Particulate Filter regeneration (DPF – Regen). Out. The first post quantity will be lasting for longer period when required for maintaining required temperatures in SCR. The quantity may vary between 1 to 3 mg/stroke. However the 2nd post quantity will be required only in case of DPF regeneration. The quantity may vary between 6 to 12 mg/stroke between 10 to 12 minutes. Fuel injections as the pilot fuel injections are made after the piston has started moving towards the bottom dead centre during the combustion stage, when the crank angle is between -5 to -25 degrees. It must be noted that, the quantity of fuel injected in after fuel injection is less than fuel quantities injected during either of the pilot, main, and post fuel injections, the quantities of fuel injected during the pilot and post fuel injections are equal and the quantity of fuel injected during the main fuel injection is larger than that quantity of fuel injected during either of the pilot, after and post injections.
[0019] Referring to figure 2, in the representation image of the piston, the formation of soot cloud takes place due to quenching in the squish area (10), during the combustion stage of the Diesel IC Engine. Without after fuel injection, that is along the path 20A, the air flow in the squish volume (10) is deteriorated thereby leading to larger formation of soot in the volume (indicated by 30A) as also indicated in the imaged volume (40A) of the piston. With after fuel injection, that is along the path 20B, jet flame catch up takes place that takes in remaining soot in the volume (indicated by 30B) from the squish volume (10) and allows it to be properly combusted. This leads to reduction in soot formation as indicated in the imaged volume (40B) of the piston. In other words, the heat released by combustion of fuel injected during after-fuel injection, allows for complete combustion of soot particles thereby reducing PM formation. The distribution of pilot, main, after and post fuel injections tends to provide a smoother the power generation curve for every cycle of combustion in the Diesel IC Engine, besides working to effectively reduce the emission due to improper combustion of fuel.
[0020] It can be seen in the graph (refer to Fig. 3) that with after fuel injection, during the combustion stage of the Diesel IC Engine, the quantity of soot formation decreases (30-70 % decrease in PM formation) with minimal increase in NOX formation (considered in comparison to a situation where there is no after fuel injection). It has been noted that such a distribution of fuel injection also improves fuel efficiency in the range of 3 to 5 %. The impact on NOX formation is minimal.
[0021] Figure 4 shows the schematic of a Diesel IC Engine setup that can be used for carrying out measurements as indicated in Figure 3. As per the schematic, the IC Engine’s operation is controlled by the Engine Management System. The Engine Management System also controls the fuel injectors (electrically controlled fuel injectors) to cause pilot, main, after and post fuel injections that in turn reduces the formation of soot during combustion. The exhaust from the IC engines leaves through the exhaust pipe where emissions are measured through sensors and NOX and PM emission analysers.
[0022] The Diesel IC engine of this setup is provided with features to allow for exhaust gas recirculation, this minimises the formation of NOX. The exhaust gas recirculation tends to reduce NOX formation by reducing the overall temperature achieved during combustion in the Diesel IC Engine. But, as the temperature reduces, the particulate matter (PM) formation tends to increase. The fuel injection method so disclosed herein tends to combat this problem and reduce the PM formation as well. The fuel injection that occurs in stages as per the disclosed method, tends to facilitate proper mixing and sufficient heating of the air-fuel mixture to allow its proper combustion and therefore helps reduce PM formation. This effect is replicable in different Diesel IC Engine Powered vehicles.
[0023] Technical advantages offered by the invention i.e., method for reduction of soot formation in Diesel IC engine are-
- It reduces formation of soot during the operation of Diesel IC Engine.
- It does not adversely affect the mileage of the Diesel IC Engine powered vehicles.
- It can be implemented without addition of any new component in the vehicles.
- It can be implemented in pre-existing vehicles without requiring extensive modification.
- It reduces particulate matter formation that is experienced due to the use of exhaust gas recirculation feature in Diesel IC Engines.
[0024] Therefore, the disclosed invention i.e. the method for reduction of soot formation in Diesel IC engine achieves all the set-out objectives.
[0025] It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the present invention has been herein described in terms of its preferred embodiment, those skilled in the art will recognize that the preferred embodiment herein disclosed, can be practiced with modifications within the scope of the invention herein described.
, Claims:We Claim,
1. A method for reduction of soot formation in Diesel IC engine, that can be implemented in Diesel IC Engine vehicle comprising of,
• electrically controlled fuel injectors,
• an engine management system,
wherein,
- as a first step, two separate fuel injections, identifiable as pilot fuel injections are made before the piston reaches the top dead centre during the initiation of the combustion stage of the Diesel IC Engine;
- as a second step, one fuel injection, identifiable as a main fuel injection is made when the piston reaches the top dead centre during the combustion stage of the Diesel IC Engine;
- as a third step, one fuel injection, identifiable as an after-fuel injection, is made after the piston starts moving back to the bottom dead centre during the combustion stage of the Diesel IC Engine; and
- as a fourth step, two separate fuel injections, identifiable as post fuel injections, are made after the after-fuel injection, when the piston is travelling towards the bottom dead centre during the combustion stage of the Diesel IC Engine.
2. The method for reduction of soot formation in Diesel IC engine as claimed in claim 1, wherein, the two pilot injections last for equal time intervals and inject equal quantities of Diesel fuel as the piston is travelling to the top dead centre during the initiation of Diesel Engine’s combustion stage, when the crank angle is between 15 to 5 degrees.
3. The method for reduction of soot formation in Diesel IC engine as claimed in claim 1, wherein, the main injection lasting for larger time interval than the pilot fuel injections and injecting larger fuel quantity than the pilot fuel injections is made when the piston has reached the top dead centre during the combustion stage, when the crank angle is between 5 to 1 degrees.
4. The method for reduction of soot formation in Diesel IC engine as claimed in claim 1, wherein, the after-fuel injection lasting smaller for time interval than either the pilot and main fuel injections and injecting smaller fuel quantities than the pilot and main fuel injections is made after the piston has started moving towards the bottom dead centre during the combustion stage, when the crank angle is between -1 to -5 degrees.
5. The method for reduction of soot formation in Diesel IC engine as claimed in claim 1, wherein, the two post fuel injection lasting for equal time intervals as the pilot fuel injections and injecting equal quantities of fuel as the pilot fuel injections are made after the piston has started moving towards the bottom dead centre during the combustion stage, when the crank angle is between -5 to -25 degrees.
6. The method for reduction of soot formation in Diesel IC engine as claimed in preceding claims, wherein the quantity of fuel injected in after fuel injection is less than fuel quantities injected during either of the pilot, main, and post fuel injections.
7. The method for reduction of soot formation in Diesel IC engine as claimed in claim 1, wherein the quantities of fuel injected during the pilot and post fuel injections are equal.
8. The method for reduction of soot formation in Diesel IC engine as claimed in claim 7, wherein the quantity of fuel injected during the main fuel injection is larger than that quantity of fuel injected during either of the pilot, after and post injections.
9. The method for reduction of soot formation in Diesel IC engine as claimed in claim 1, wherein the electrically controlled fuel injectors are solenoid fuel injectors that are electrically connected to the engine management system, which thereby allows them to be controlled by said engine management system.
Dated 18th day of February 2025

VIDIT CHOUBEY
(IN P/A 5566)
AGENT FOR THE APPLICANT(S)

To,
The Controller of Patents,
The Patent Office, at Mumbai