CA2863036A1 - Chamfered piston - Google Patents
Chamfered piston Download PDFInfo
- Publication number
- CA2863036A1 CA2863036A1 CA2863036A CA2863036A CA2863036A1 CA 2863036 A1 CA2863036 A1 CA 2863036A1 CA 2863036 A CA2863036 A CA 2863036A CA 2863036 A CA2863036 A CA 2863036A CA 2863036 A1 CA2863036 A1 CA 2863036A1
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- Prior art keywords
- piston
- chamfer
- chamfered
- fuel
- top surface
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02F3/00—Pistons
- F02F3/28—Other pistons with specially-shaped head
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Combustion Methods Of Internal-Combustion Engines (AREA)
Abstract
Pistons designed for compression ignition engines operating in the Diesel-cycle where Diesel fuel burns in a diffusion combustion mode result in increased unburned hydrocarbon emissions when the engines are converted to burn a gaseous fuel in a premixed combustion mode. A piston for reciprocation in a cylinder bore along a longitudinal axis thereof in an internal combustion engine operating in a premixed combustion mode, the piston comprises a top surface partially defining a combustion chamber; an outer surface facing the cylinder bore; and an annular groove in the outer surface extending around the longitudinal axis; wherein the piston has a chamfered edge extending from the top surface to the outer surface spaced apart from the annular groove wherein a chamfer angle is selected to reduce unburned hydrocarbons compared to when the piston is not chamfered.
Description
CHAMFERED PISTON
Field of the Invention [0001] The present application relates to a piston in an internal combustion engine operating in a premixed combustion mode.
Background of the Invention
Field of the Invention [0001] The present application relates to a piston in an internal combustion engine operating in a premixed combustion mode.
Background of the Invention
[0002] Compression ignition engines operating on diesel are designed to introduce the fuel directly into combustion chambers later in the compression stroke using a high pressure injection system. The fuel forms a stratified charge and burns in a diffusion combustion mode. When converting compression ignition engines from being fuelled with diesel to being fuelled with a gaseous fuel, such as natural gas, the gaseous fuel is typically introduced upstream of intake valves associated with respective engine cylinders by a low pressure injection system. The fuel is mixed with intake air, and in some cases exhaust gases from an exhaust gas recirculation (EGR) system, to form a combustible mixture. The mixture is later ignited in the engine cylinders by an ignition source, which can be combustion of a pilot fuel or a positive ignition source such as a spark plug, and combustion proceeds in a premixed combustion mode.
[0003] A problem with the amount of unburned hydrocarbons arises when using the piston designed for the compression ignition engine operating on diesel, the "diesel piston", for premixed combustion of natural gas, which it is not designed or optimized for. With reference to FIG. 1, diesel piston 10 has a large top-land volume, which is defined herein to be the volume in crevice 20 between the diesel piston and liner 30 associated with cylinder wall 40, above piston ring 45 disposed in groove 50 and plane 15 of the top-land of the piston. The premixed air-fuel charge penetrates into crevice 20, unlike the stratified charge that forms when fuelled with diesel which is injected late in the compression stroke. It is difficult for the flame front of the premixed flame resulting from combusting the gaseous fuel to reach deep into crevice 20 due to excessive heat loss to diesel piston 10 and liner 30. As a result, compression ignition engines operating in a premixed combustion mode often see high unburned hydrocarbon emissions due to fuel trapped in crevice 20.
[0004] Previously, to reduce the top-land volume the radial distance from piston 10 to liner 30 was reduced, and piston ring 50 was raised to decrease the depth of crevice 20.
This led to issues with piston thermal management and increased the chance of piston failure. In addition, replacing the existing diesel piston 10 with a new piston increased the cost of conversion.
This led to issues with piston thermal management and increased the chance of piston failure. In addition, replacing the existing diesel piston 10 with a new piston increased the cost of conversion.
[0005] The state of the art is lacking in techniques for reducing unburned hydrocarbon emissions in compression ignition engines operating in a premixed combustion mode. The present method and apparatus provides a technique for improving these emissions.
Summary of the Invention
Summary of the Invention
[0006] An improved piston for reciprocation in a cylinder bore along a longitudinal axis thereof in an internal combustion engine operating in a premixed combustion mode, the piston comprises a top surface partially defining a combustion chamber; an outer surface facing the cylinder bore; and an annular groove in the outer surface extending around the longitudinal axis; wherein the piston has a chamfered edge extending from the top surface to the outer surface spaced apart from the annular groove, wherein a chamfer angle is selected to reduce unburned hydrocarbons compared to when the piston is not chamfered.
[0007] An improved piston manufactured for an internal combustion engine designed to operate in a diffusion combustion mode, modified for operation in a premixed combustion mode, the piston for reciprocation in a cylinder bore along a longitudinal axis thereof, the piston comprises a top surface partially defining a combustion chamber; an outer surface facing by the cylinder bore; and an annular groove in the outer surface extending around the longitudinal axis; wherein the piston has a chamfered edge extending from the top surface to the outer surface spaced apart from the annular groove, wherein a chamfer angle is selected to reduce unburned hydrocarbons compared to when the piston is not chamfered.
[0008] A gaseous fuel is the fuel that burns in the premixed combustion mode.
In a preferred embodiment, the internal combustion engine is a dual fuel engine and the gaseous fuel is ignited by a pilot fuel. The dual fuel engine has a compression ratio of at least 15:1. In a preferred embodiment, the mass of unburned gaseous fuel is reduced by at least 30%. A chamfer depth is between a range of 5 mm and 7mm, and in a preferred embodiment the chamfer depth is approximately 6 mm. The chamfer angle is between a range of 30 and 60 , and in a preferred embodiment the angle is approximately 45 . In another preferred embodiment, after the chamfer angle is selected, the chamfer depth is selected such that the compression ratio is at least 15:1 and the chamfer does not intersect a piston ring groove. The piston further comprises at least one of an intersection between a chamfer surface and the top surface is rounded to reduce thermal load; and an intersection between the chamfer surface and the outer surface is rounded to reduce thermal load. A residual volume is less than 2.5%, and preferably less than 1%. A
compression ratio when operating in the diffusion combustion mode can be reduced when operating in the premixed combustion mode.
In a preferred embodiment, the internal combustion engine is a dual fuel engine and the gaseous fuel is ignited by a pilot fuel. The dual fuel engine has a compression ratio of at least 15:1. In a preferred embodiment, the mass of unburned gaseous fuel is reduced by at least 30%. A chamfer depth is between a range of 5 mm and 7mm, and in a preferred embodiment the chamfer depth is approximately 6 mm. The chamfer angle is between a range of 30 and 60 , and in a preferred embodiment the angle is approximately 45 . In another preferred embodiment, after the chamfer angle is selected, the chamfer depth is selected such that the compression ratio is at least 15:1 and the chamfer does not intersect a piston ring groove. The piston further comprises at least one of an intersection between a chamfer surface and the top surface is rounded to reduce thermal load; and an intersection between the chamfer surface and the outer surface is rounded to reduce thermal load. A residual volume is less than 2.5%, and preferably less than 1%. A
compression ratio when operating in the diffusion combustion mode can be reduced when operating in the premixed combustion mode.
[0009] An improved method of modifying a piston designed for an internal combustion engine operating in a diffusion combustion mode to operating in a premixed combustion method, the piston comprising a top surface partially defining a combustion chamber and an outer surface facing a cylinder bore of the internal combustion engine, the method comprising chamfering an edge of the piston defined by an intersection between the top surface and the outer surface, wherein a chamfer angle is selected to reduce unburned hydrocarbons compared to when the piston is not chamfered. The method further comprising selecting a chamfer depth such that a compression ratio is at least 15:1, the chamfer angle and the chamfer depth cooperating to reduce unburned hydrocarbon emissions compared to when the piston is not chamfered.
Brief Description of the Drawings
Brief Description of the Drawings
[0010] FIG. 1 is a schematic view of a prior art piston for a compression ignition engine operating on diesel fuel.
[0011] FIG. 2 is a schematic view of a piston for a compression ignition engine operating on a gaseous fuel in a premixed combustion mode according to one embodiment.
[0012] FIG. 3 is a cross-sectional view of the piston of FIG. 2.
[0013] FIG. 4 is a chart view tabulating emission results from computational fluid dynamic simulations employing the piston of FIG. 2 having a variety of chamfers.
Detailed Description of Preferred Embodiment(s)
Detailed Description of Preferred Embodiment(s)
[0014] Referring to FIGS. 2 and 3, piston 12 is an embodiment of piston 10 modified for operation in an internal combustion engine consuming a gaseous fuel in a premixed combustion mode. Piston 12 reciprocates along longitudinal axis 70 of a cylinder bore of the internal combustion engine defined by liner 30 and cylinder wall 40.
Combustion chamber 100 is defined partially by top surface 90 of piston 12, liner 30 and a cylinder head (not shown). Piston 12 comprises piston bowl 95 (seen in FIG. 3) that further defines combustion chamber 100. Chamfer 80 is formed at the intersection of top surface 90 and outer surface 110 of the piston, by removing edge 60 as seen in FIG. 1.
Edge 82 is annular around longitudinal axis 70 and is defined by the intersection between top surface 90 and chamfer surface 86. Edge 84 is similarly annular and defined by the intersection between outer surface 110 and chamfer surface 86. Chamfer 80 is defined by chamfer angle 0 and chamfer depth h. Chamfer angle 0 is the angle between top surface 90 and chamfer surface 86. Chamfer depth h is the axial distance along longitudinal axis 70 between top surface 90 and edge 84. For a particular chamfer angle 0, chamfer depth h is selected such that chamfer 80 does not intersect piston ring groove 50, and, in combination with the chamfer angle, such that unburned hydrocarbon emissions are reduced. Volume 25 is defined as a residual volume between piston ring 45, outer surface 110, liner 30 and plane 35, where the plane is horizontal to the piston ring and intersects chamfer edge 84. It is desirable to constrain the size of volume 25 such that the flame front can penetrate this volume, and if the flame front cannot penetrate this volume to reduce the amount of unburned hydrocarbons. Preferably, volume 25 is less than 2.5% of combustion chamber volume when piston 12 is at top dead center, and more preferably less than 1%. Relatively speaking, typical top-land volumes for unchamfered piston 10 shown in FIG. 1 can be greater than 4% of the combustion chamber volume when the piston is at the top dead center position.
100151 In operation, gaseous fuel and intake air are introduced into combustion chamber 100 where they form a homogenous, premixed air-fuel charge, which may include recirculated EGR gas. Prior to ignition, the premixed air-fuel charge extends into crevice 21. Chamfer 80 opens up the top-land volume and allows the flame front of the premixed flame to travel deeper into crevice 21 to better consume the fuel, thereby reducing unburned hydrocarbon emissions. When converting a diesel engine that operates in diffusion combustion mode to operate in premixed combustion mode, diesel piston 10 of FIG. 1 can be modified by forming chamfer 80 (a relatively inexpensive modification), avoiding the necessity to replace the piston with another one (a relatively expensive modification). In this manner all the other performance characteristics associated with piston 10 remain. Chamfer 80 increases the volume of the combustion chamber, since material is removed from the piston, reducing the compression ratio of the engine.
Reducing the compression ratio is undesirable for conventional diesel engines because they are designed for high compression ratios to facilitate compression ignition and there is no problem with fuel being trapped in the crevice because late cycle injection forms a stratified charge for a diffusion combustion mode. However, reducing the compression ratio is often desirable when running a compression ignition engine in premixed combustion mode to reduce the likelihood of premature ignition and engine knock. An example of such an engine is a dual fuel engine that employs a gaseous fuel as a main fuel, which forms a premixed air-fuel charge in the combustion chamber that is ignited by a pilot fuel, such as diesel. In this disclosure, premature ignition is the ignition of the air-fuel charge before a predetermined ignition event, and engine knock occurs after the predetermined ignition event and is the ignition of portions of the air-fuel charge prior to ignition by the advancing flame front of the premixed flame. It is preferred that the compression ratio remains at least 15:1 for the dual fuel engine such that the pilot fuel can be compression ignited, especially when the engine is starting.
100161 A series of computational fluid dynamic (CFD) simulations were performed to investigate the effectiveness of the chamfered piston. A variety of chamfers were tested, each defined by a unique chamfer angle 0 and depth h, to determine the impact on emissions. Each simulation employed a unique chamfer and entailed combustion of a premixed air-fuel charge in a combustion chamber and the measurement of the resulting emissions. The emission results for all the simulations are graphed in FIG.4.
Baseline simulation 200 employed the unchamfered piston 10 from FIG. 1, and simulations through 209 employed piston 12 with various chamfer angles 0 and depths h as tabulated in Table. 1. In FIG. 4, for each simulation 200 through 209, the left hand bars are the nitrous oxide (N0x) emissions, the middle bars are the carbon monoxide (CO) emissions and the right hand bars are the unburned hydrocarbon (CH4) emissions.
Simulation Chamfer Chamfer Angle Depth (mm) (degrees) Table 1 100171 A surprising result of the simulations was that not all chamfer angles and depths resulted in improved unburned hydrocarbon (CH4) emissions compared to baseline test 200. In simulations 201 and 205 the unburned hydrocarbon (CH4) emissions actually increased (got worse). This illustrates the unpredictable behavior of the combustion environment in general, and the difficulty in predicting the behavior of the flame front in crevice 21 in particular, and the significance of optimizing chamfer angle and chamfer depth for achieving increased reduction in unburned hydrocarbon emissions.
In simulations 201 through 209, the nitrous oxide (N0x) emissions increased slightly, but within acceptable limits, and the carbon monoxide (CO) emissions decreased compared to baseline test 200. The chamfer employed in simulation 206 has been identified as an exemplary modification to piston 210, where unburned hydrocarbon (CH4) emissions are reduced and the compression ratio has been decreased enough to reduce the likelihood of premature ignition and engine knock, but not to significantly decrease the volumetric efficiency of the engine. Fixing chamber angle 0 at a preferred value, such as 45 , chamfer depth h can be selected such that the compression ratio is at least
Combustion chamber 100 is defined partially by top surface 90 of piston 12, liner 30 and a cylinder head (not shown). Piston 12 comprises piston bowl 95 (seen in FIG. 3) that further defines combustion chamber 100. Chamfer 80 is formed at the intersection of top surface 90 and outer surface 110 of the piston, by removing edge 60 as seen in FIG. 1.
Edge 82 is annular around longitudinal axis 70 and is defined by the intersection between top surface 90 and chamfer surface 86. Edge 84 is similarly annular and defined by the intersection between outer surface 110 and chamfer surface 86. Chamfer 80 is defined by chamfer angle 0 and chamfer depth h. Chamfer angle 0 is the angle between top surface 90 and chamfer surface 86. Chamfer depth h is the axial distance along longitudinal axis 70 between top surface 90 and edge 84. For a particular chamfer angle 0, chamfer depth h is selected such that chamfer 80 does not intersect piston ring groove 50, and, in combination with the chamfer angle, such that unburned hydrocarbon emissions are reduced. Volume 25 is defined as a residual volume between piston ring 45, outer surface 110, liner 30 and plane 35, where the plane is horizontal to the piston ring and intersects chamfer edge 84. It is desirable to constrain the size of volume 25 such that the flame front can penetrate this volume, and if the flame front cannot penetrate this volume to reduce the amount of unburned hydrocarbons. Preferably, volume 25 is less than 2.5% of combustion chamber volume when piston 12 is at top dead center, and more preferably less than 1%. Relatively speaking, typical top-land volumes for unchamfered piston 10 shown in FIG. 1 can be greater than 4% of the combustion chamber volume when the piston is at the top dead center position.
100151 In operation, gaseous fuel and intake air are introduced into combustion chamber 100 where they form a homogenous, premixed air-fuel charge, which may include recirculated EGR gas. Prior to ignition, the premixed air-fuel charge extends into crevice 21. Chamfer 80 opens up the top-land volume and allows the flame front of the premixed flame to travel deeper into crevice 21 to better consume the fuel, thereby reducing unburned hydrocarbon emissions. When converting a diesel engine that operates in diffusion combustion mode to operate in premixed combustion mode, diesel piston 10 of FIG. 1 can be modified by forming chamfer 80 (a relatively inexpensive modification), avoiding the necessity to replace the piston with another one (a relatively expensive modification). In this manner all the other performance characteristics associated with piston 10 remain. Chamfer 80 increases the volume of the combustion chamber, since material is removed from the piston, reducing the compression ratio of the engine.
Reducing the compression ratio is undesirable for conventional diesel engines because they are designed for high compression ratios to facilitate compression ignition and there is no problem with fuel being trapped in the crevice because late cycle injection forms a stratified charge for a diffusion combustion mode. However, reducing the compression ratio is often desirable when running a compression ignition engine in premixed combustion mode to reduce the likelihood of premature ignition and engine knock. An example of such an engine is a dual fuel engine that employs a gaseous fuel as a main fuel, which forms a premixed air-fuel charge in the combustion chamber that is ignited by a pilot fuel, such as diesel. In this disclosure, premature ignition is the ignition of the air-fuel charge before a predetermined ignition event, and engine knock occurs after the predetermined ignition event and is the ignition of portions of the air-fuel charge prior to ignition by the advancing flame front of the premixed flame. It is preferred that the compression ratio remains at least 15:1 for the dual fuel engine such that the pilot fuel can be compression ignited, especially when the engine is starting.
100161 A series of computational fluid dynamic (CFD) simulations were performed to investigate the effectiveness of the chamfered piston. A variety of chamfers were tested, each defined by a unique chamfer angle 0 and depth h, to determine the impact on emissions. Each simulation employed a unique chamfer and entailed combustion of a premixed air-fuel charge in a combustion chamber and the measurement of the resulting emissions. The emission results for all the simulations are graphed in FIG.4.
Baseline simulation 200 employed the unchamfered piston 10 from FIG. 1, and simulations through 209 employed piston 12 with various chamfer angles 0 and depths h as tabulated in Table. 1. In FIG. 4, for each simulation 200 through 209, the left hand bars are the nitrous oxide (N0x) emissions, the middle bars are the carbon monoxide (CO) emissions and the right hand bars are the unburned hydrocarbon (CH4) emissions.
Simulation Chamfer Chamfer Angle Depth (mm) (degrees) Table 1 100171 A surprising result of the simulations was that not all chamfer angles and depths resulted in improved unburned hydrocarbon (CH4) emissions compared to baseline test 200. In simulations 201 and 205 the unburned hydrocarbon (CH4) emissions actually increased (got worse). This illustrates the unpredictable behavior of the combustion environment in general, and the difficulty in predicting the behavior of the flame front in crevice 21 in particular, and the significance of optimizing chamfer angle and chamfer depth for achieving increased reduction in unburned hydrocarbon emissions.
In simulations 201 through 209, the nitrous oxide (N0x) emissions increased slightly, but within acceptable limits, and the carbon monoxide (CO) emissions decreased compared to baseline test 200. The chamfer employed in simulation 206 has been identified as an exemplary modification to piston 210, where unburned hydrocarbon (CH4) emissions are reduced and the compression ratio has been decreased enough to reduce the likelihood of premature ignition and engine knock, but not to significantly decrease the volumetric efficiency of the engine. Fixing chamber angle 0 at a preferred value, such as 45 , chamfer depth h can be selected such that the compression ratio is at least
15: 1 and such that chamfer 80 does not intersect piston ring groove 50. A thermal analysis of the pistons in simulations 201 through 209 revealed that edges 82 and 84 of chamfer 80 concentrate heat, and to reduce such thermal loading these edges can be rounded.
100181 While particular elements, embodiments and applications of the present invention have been shown and described, it will be understood, that the invention is not limited thereto since modifications can be made by those skilled in the art without departing from the scope of the present disclosure, particularly in light of the foregoing teachings.
100181 While particular elements, embodiments and applications of the present invention have been shown and described, it will be understood, that the invention is not limited thereto since modifications can be made by those skilled in the art without departing from the scope of the present disclosure, particularly in light of the foregoing teachings.
Claims (22)
1. A piston for reciprocation in a cylinder bore along a longitudinal axis thereof in an internal combustion engine operating in a premixed combustion mode, the piston comprising:
a top surface partially defining a combustion chamber;
an outer surface facing the cylinder bore; and an annular groove in the outer surface extending around the longitudinal axis;
wherein the piston has a chamfered edge extending from the top surface to the outer surface spaced apart from the annular groove, wherein a chamfer angle is selected to reduce unburned hydrocarbons compared to when the piston is not chamfered.
a top surface partially defining a combustion chamber;
an outer surface facing the cylinder bore; and an annular groove in the outer surface extending around the longitudinal axis;
wherein the piston has a chamfered edge extending from the top surface to the outer surface spaced apart from the annular groove, wherein a chamfer angle is selected to reduce unburned hydrocarbons compared to when the piston is not chamfered.
2. The piston of claim 1, wherein the mass of unburned gaseous fuel is reduced by at least 30% compared to when the piston is not chamfered.
3. The piston of claim 1, wherein a chamfer depth is between a range of 5 mm and 7mm.
4. The piston of claim 3, wherein the chamfer depth is approximately 6 mm.
5. The piston of claim 1, wherein the chamfer angle is between a range of 30° and 60°.
6. The piston of claim 5, wherein the chamfer angle is approximately 45°.
7. The piston of claim 5, wherein a chamfer depth is selected such that a compression ratio is at least 15:1, the chamfer angle and the chamfer depth cooperating to reduce unburned hydrocarbon emissions compared to when the piston is not chamfered.
8. The piston of claim 1, wherein a gaseous fuel is the fuel that burns in the premixed combustion mode.
9. The piston of claim 8, wherein the internal combustion engine is a dual fuel engine and the gaseous fuel is ignited by a pilot fuel.
10. The piston of claim 1, wherein at least one of:
an intersection between a chamfer surface and the top surface is rounded to reduce thermal load; and an intersection between the chamfer surface and the outer surface is rounded to reduce thermal load.
an intersection between a chamfer surface and the top surface is rounded to reduce thermal load; and an intersection between the chamfer surface and the outer surface is rounded to reduce thermal load.
11. The piston of claim 1, wherein a residual volume is less than 2.5% of the combustion chamber volume when the piston is at a top dead center position in the cylinder bore.
12. The piston of claim 11, wherein the residual volume is less than 1%.
13. A piston manufactured for an internal combustion engine designed to operate in a diffusion combustion mode, modified for operation in a premixed combustion mode, the piston for reciprocation in a cylinder bore along a longitudinal axis thereof, the piston comprising:
a top surface partially defining a combustion chamber;
an outer surface facing by the cylinder bore; and an annular groove in the outer surface extending around the longitudinal axis;
wherein the piston has a chamfered edge extending from the top surface to the outer surface spaced apart from the annular groove, wherein a chamfer angle is selected to reduce unburned hydrocarbons compared to when the piston is not chamfered.
a top surface partially defining a combustion chamber;
an outer surface facing by the cylinder bore; and an annular groove in the outer surface extending around the longitudinal axis;
wherein the piston has a chamfered edge extending from the top surface to the outer surface spaced apart from the annular groove, wherein a chamfer angle is selected to reduce unburned hydrocarbons compared to when the piston is not chamfered.
14. The piston of claim 13, wherein unburned gaseous fuel is reduced by at least 30%.
15. The piston of claim 13, wherein the chamfer angle is between a range of 30° and 60°.
16. The piston of claim 15, wherein a chamfer depth is selected such that a compression ratio is at least 15:1, the chamfer angle and the chamfer depth cooperating to reduce unburned hydrocarbon emissions compared to when the piston is not chamfered.
17. The piston of claim 13, wherein a gaseous fuel is the fuel that burns in the premixed combustion mode.
18. The piston of claim 17, wherein the internal combustion engine is a dual fuel engine and the gaseous fuel is ignited by a pilot fuel.
19. The piston of claim 13, wherein at least one of:
an intersection between a chamfer surface and the top surface is rounded to reduce thermal load ; and an intersection between a chamfer surface and the outer surface is rounded to reduce thermal load.
an intersection between a chamfer surface and the top surface is rounded to reduce thermal load ; and an intersection between a chamfer surface and the outer surface is rounded to reduce thermal load.
20. The piston of claim 13, wherein a residual volume is less than 2.5% of the combustion chamber volume when the piston is at a top dead center position in the cylinder bore.
21. A method of modifying a piston designed for an internal combustion engine operating in a diffusion combustion mode to operating in a premixed combustion method, the piston comprising a top surface partially defining a combustion chamber and an outer surface facing a cylinder bore of the internal combustion engine, the method comprising chamfering an edge of the piston defined by an intersection between the top surface and the outer surface, wherein a chamfer angle is selected to reduce unburned hydrocarbons compared to when the piston is not chamfered.
22. The method of claim 21, further comprising selecting a chamfer depth such that a compression ratio is at least 15:1, the chamfer angle and the chamfer depth cooperating to reduce unburned hydrocarbon emissions compared to when the piston is not chamfered.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2863036A CA2863036A1 (en) | 2014-09-10 | 2014-09-10 | Chamfered piston |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2863036A CA2863036A1 (en) | 2014-09-10 | 2014-09-10 | Chamfered piston |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2863036A1 true CA2863036A1 (en) | 2014-10-29 |
Family
ID=51831067
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2863036A Abandoned CA2863036A1 (en) | 2014-09-10 | 2014-09-10 | Chamfered piston |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2863036A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017079054A1 (en) | 2015-11-02 | 2017-05-11 | Caterpillar Inc. | Engine piston having a notched top land |
| DE102017117019A1 (en) | 2016-07-29 | 2018-02-15 | Caterpillar Inc. | CONSTRUCTION FOR A PISTON FIRE BAR |
-
2014
- 2014-09-10 CA CA2863036A patent/CA2863036A1/en not_active Abandoned
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017079054A1 (en) | 2015-11-02 | 2017-05-11 | Caterpillar Inc. | Engine piston having a notched top land |
| US9822729B2 (en) | 2015-11-02 | 2017-11-21 | Caterpillar Inc. | Engine piston having a notched top land |
| DE102017117019A1 (en) | 2016-07-29 | 2018-02-15 | Caterpillar Inc. | CONSTRUCTION FOR A PISTON FIRE BAR |
| US10030604B2 (en) | 2016-07-29 | 2018-07-24 | Caterpillar Inc. | Piston top land structure |
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| Date | Code | Title | Description |
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| FZDE | Dead |
Effective date: 20160216 |