Internal combustion engine with dual-channel cylinder liner cooling

Abstract

A cylinder liner is provided, which includes a cylinder bore capable of accommodating a piston, a top end having an annular flange, a first cylindrical section, a second cylindrical section, and an annular ridge separating the first cylindrical section and the second cylindrical section. When used in a cylinder bore of an engine block, the cylinder liner provides two channels to allow coolant to be supplied to the cylinder liner.

Description

Technical Field

[0001] The present invention relates to an internal combustion engine, and more particularly to an internal combustion engine having dual-channel cylinder liner cooling. Background Art

[0002] Internal combustion engines are typically liquid-cooled. Conventional coolant systems for internal combustion engines may include a coolant pump that pumps coolant into coolant channels in the engine. In some internal combustion engines, replaceable cylinder liners define the cylinders and partially define the combustion chambers of the engine.

[0003] During combustion, an internal combustion engine can generate a large amount of heat. In some engines, coolant channels are provided between and around the cylinder liners. Coolant can be directed through the coolant channels to cool the cylinder liners and carry thermal energy away from the cylinders. However, since the top of each cylinder liner where combustion occurs experiences a higher temperature, the thermal energy is unevenly distributed in each cylinder liner.

[0004] U.S. Patent No. 8,443,768 to Berghian et al. discloses an engine cylinder liner having a main coolant channel and a secondary coolant channel around the upper portion of the cylinder liner. The secondary coolant channel has a wavy configuration that is designed to substantially increase the contact surface of the coolant in the secondary coolant channel. Summary of the Invention

[0005] In one aspect of the present invention, there is provided an internal combustion engine including a cylinder head, a piston, and an engine block having a liner bore and a cylinder liner embedded in the liner bore, wherein a first annular coolant channel having a channel top end and a channel bottom end is formed between the liner bore and the cylinder liner; the cylinder liner includes: a cylinder bore for receiving the piston, the piston being slidably received in the cylinder bore for reciprocating movement between a top dead center position and a bottom dead center position; and a top end having an annular flange; wherein, when in the top dead center position, the channel top end is closer to the top end of the cylinder liner than the piston.

[0006] In another aspect of the present invention, there is provided a cylinder liner including: a cylinder bore capable of receiving a piston, a top end having an annular flange, a first cylindrical section serving as a first coolant groove, a second cylindrical section serving as a second coolant groove, and an annular ridge separating the first cylindrical section and the second cylindrical section.

[0007] In another aspect of the present invention, a cooling system is provided, which includes coolant in fluid communication with a water pump, an oil cooler, a thermostat housing, a radiator, and an engine block and cylinder head assembly including a cylinder head, a piston, and an engine block, the engine block having a cylinder bore and a cylinder liner embedded in the cylinder bore, wherein a first annular channel having an annular channel top end and an annular channel bottom end is formed between the cylinder bore and the cylinder liner; wherein the cylinder liner includes: a cylinder bore for accommodating the piston, the piston being capable of performing a piston stroke including a top dead center; a top end having an annular flange; a first cylindrical section; a second cylindrical section; and an annular ridge separating the first cylindrical section and the second cylindrical section; wherein the annular channel top end is closer to the top end of the cylinder liner than the top dead center of the piston.

[0008] Other features and aspects of the present invention will become readily apparent from the following description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Other features and advantages of the present invention will become readily apparent by describing embodiments with reference to the drawings. In the drawings:

[0010] Figure 1 is a partial cross-sectional view of a part of an internal combustion engine, which includes an exemplary cylinder liner received in a cylinder bore of an engine block;

[0011] Figure 2 is a schematic view of an embodiment of an exemplary engine cooling system;

[0012] Figure 3 is a perspective view of an embodiment of an exemplary cylinder liner;

[0013] Figure 4 is Figure 1 a partial cross-sectional view of the cylinder liner and the engine block of

[0014] Figure 5 a view showing coolant flowing through a channel formed by the cylinder liner; and

[0015] Figure 6 is Figure 1 a cross-sectional view of the cylinder liner and the engine block of DETAILED DESCRIPTION

[0016] Referring to the drawings, Figure 1is a partial cross-sectional view of a portion of an internal combustion engine 10, such as a diesel engine. The internal combustion engine 10 can power various types of applications and / or machines. For example, the internal combustion engine 10 can power machines such as off-road trucks, railroad locomotives, earthmoving machines (e.g., wheel loaders, excavators, dump trucks, backhoes, motor graders, material handlers, etc.). The term "machine" can also refer to stationary equipment, such as a generator driven by the internal combustion engine 10 to generate electricity.

[0017] Figure 2 is a schematic diagram of an exemplary cooling system 50. In the cooling system 50, a water pump 52 pumps coolant into an oil cooler 54. The coolant leaves the oil cooler and enters the cylinder block and head 56. When the coolant is in the engine block, it enters one or more channels, as described further below, and the coolant is supplied to the cylinders of the internal combustion engine 10. The coolant leaves the cylinder block and head 56 and enters a thermostat housing 58. If the coolant is above a threshold temperature, the coolant leaving the thermostat housing 58 will be directed to a radiator 60 for cooling. If the coolant is below the threshold temperature, the coolant leaving the thermostat housing 58 will return to the water pump via a bypass circuit 62. The water pump 52 can optionally pump the coolant into an aftercooler 64 for an optional turbine (not shown). In some embodiments, the coolant after leaving the aftercooler 64 can be mixed with the coolant leaving the oil cooler before entering the cylinder block and head 56. In other embodiments, the coolant can be directed to the thermostat housing 58 after leaving the aftercooler 64.

[0018] Return Figure 1, the internal combustion engine 10 includes a cylinder head 300 attached to the engine block 200. The engine block 200 includes a chamber forming a cylinder bore 214. The cylinder bore 214 is lined with a cylinder liner 100. As used herein, the cylinder bore 214 lined with the cylinder liner 100 may be referred to as a cylinder assembly or simply a cylinder. The cylinder liner 100 includes an inner surface 120 defining a cylinder bore 106 configured to receive a piston 212 that reciprocates within the cylinder bore 106 during operation of the internal combustion engine 10. The region defined by the cylinder bore 106 of the cylinder liner 100, the cylinder head 300, and the piston 212 forms a combustion chamber 216. In the combustion chamber 216, a mixture of air and fuel burns to provide power to drive the piston 212 away from the cylinder head 300. The cylinder head 300 includes at least one valve 302 that permits one or more functions selected from air intake into the combustion chamber 216, fuel intake into the combustion chamber 216, and exhaust gas discharge from the combustion chamber 216. Suitable types of internal combustion engines include spark ignition engines or compression ignition engines (e.g., diesel engines or dual fuel engines). The internal combustion engine 10 may include any number of cylinders. Each cylinder of the internal combustion engine 10 may individually have a single cylinder head 300. Alternatively, two or more cylinders may be associated with the cylinder head 300.

[0019] When received within the cylinder bore 214, the cylinder liner 100 combines with the cylinder bore 214 to form a first annular coolant passage 250 and a second annular passage 252 located below the first annular coolant passage 250, both of which permit coolant to pass therethrough to cool the cylinder liner 100. The coolant is pumped through the coolant passages within the internal combustion engine 10, and each of the first annular coolant passage 250 and the second annular coolant passage 252 may be supplied from one or more coolant passages 254 (out of plane and shown in a cross-sectional view). One or more coolant passages 254 may be configured to receive coolant from the cylinder head 300. For example, one or more coolant passages 254 may receive coolant from a cylinder head water jacket (not shown). Suitable coolants include, but are not limited to, water, ethylene glycol, or mixtures thereof.

[0020] Figure 3is a perspective view of an exemplary embodiment of a cylinder liner 100. The cylinder liner 100 has a hollow, generally cylindrical body that includes a top end 102 and a bottom end 104. The cylinder liner 100 includes a cylinder bore 106 that longitudinally extends through the center of the cylinder liner 100 from the top end 102 to the bottom end 104. As described above, the cylinder bore 106 is defined by an inner surface 120. The cylinder liner 100 also includes an outer surface 122 that is opposite and parallel to the inner surface 120. Located at the top end 102 is an annular flange 108 that radially projects outwardly from the outer surface 122 of the cylinder liner 100. The annular flange 108 can be configured to rest in a recessed area 204 of the engine block 200. As Figure 1 shown, the engine block 200 includes a recessed area 204 that supports the annular flange 108 of the cylinder liner 100. The recessed area 204 allows the annular flange 108 of the cylinder liner 100 to be positioned below the surface of the engine block plate 220. Thus, the annular flange 108 of the cylinder liner 100 is buried in the engine block 200.

[0021] The cylinder liner 100 also includes an annular ridge 112 that radially projects outwardly from the cylindrical body of the cylinder liner 100. The annular ridge 112 can also be referred to as a pilot diameter. The annular ridge 112 divides the cylindrical body of the cylinder liner 100 to form a first cylindrical section 114 and a second cylindrical section 116. The first cylindrical section 114 spans the length of the cylinder liner 100 between the annular flange 108 and the annular ridge 112. When the cylinder liner 100 is received in the cylinder bore 214 of the engine block 200, a first annular coolant passage 250 is formed to allow coolant to pass around the cylinder liner 100 at the first cylinder section 114. The first cylindrical section 114 has a smooth surface. The smooth surface of the first cylindrical section 114 can transition to each of the annular flange 108 and the annular ridge 112 via a fillet.

[0022] Similar to the first cylindrical section 114, when the cylinder liner 100 is received in the cylinder bore 214 of the engine block 200, a second annular coolant passage 252 is formed to allow coolant to pass around the cylinder liner 100 at the second cylindrical section 116. The second cylindrical section 116 has a smooth surface. The smooth surface of the second cylindrical section 116 can taper to meet the annular ridge 112. The cylinder liner 100 can be made of any suitable one or more materials, such as alloy gray iron, aluminum, or steel (e.g., stainless steel).

[0023] Figure 4is a partial cross-sectional view of the cylinder liner 100 and the engine block 200, and best shows the interface where the annular ridge 112 and the annular flange 108 meet the cylinder bore 214 of the engine block 200. As described above, the engine block 200 includes a recessed area 204. Located at the bottom of the recessed area 204 is a radially extending upward shoulder 206. Below the radially extending upward shoulder 206 in the cylinder bore 214 of the engine block 200 is the cylinder bore ridge 218. Located between the recessed area 204 and the liner bore ridge 218 is the cylinder bore groove 208. The cylinder bore groove 208 may have a continuous shape or a discontinuous shape (e.g., it may vary in shape or size). Below the cylinder bore ridge 218 of the engine block 200 is the inner surface of the cylinder bore 210.

[0024] The annular flange 108 of the cylinder liner 100 includes a lower surface 110. When the cylinder liner 100 is inserted into the cylinder bore 214, the lower surface 110 of the cylinder liner 100 engages the radially extending upward shoulder 206 of the engine block 200. In addition, the annular ridge 112 of the cylinder liner 100 engages the cylinder bore ridge 218. A first annular coolant passage 250 is formed between the first cylindrical section 114 of the cylinder liner 100 and the cylinder bore groove 208. In some embodiments, the first cylindrical section 114 and the cylinder bore groove 208 do not contact each other within the first annular coolant passage 250. The radially extending upward shoulder 206 and the lower surface 110 engage to form an interface that defines the top of the first annular coolant passage 250. The lower surface 110 of the cylinder liner 100 and the radially extending upward shoulder 206 of the engine block 200 are machined to form a smooth surface. Thus, when coolant flows through the first annular coolant passage 250, the coolant remains within the first annular coolant passage 250 without the need for a secondary seal (e.g., the seal is provided only by the interface between the cylinder liner and the cylinder bore). This provides the ability to locate the first annular coolant passage 250 closer to the top end 102.

[0025] A second annular coolant passage 252 is formed between the second cylindrical section 116 of the cylinder liner 100 and the inner surface of the cylinder liner bore 210. When the cylinder liner 100 is inserted into the cylinder liner bore 214, an interface is formed between the liner bore ridge 218 of the cylinder liner 100 and the annular ridge 112. The interface between the liner bore ridge 218 and the annular ridge 112 forms a seal and separates the first annular coolant passage 250 from the second annular coolant passage 252. While the liner bore ridge 218 and the annular ridge 112 form a seal, under certain conditions, such as during use in extremely cold temperatures, the seal may allow some coolant crosstalk between the first annular coolant passage 250 and the second annular coolant passage 252. In certain embodiments, an incomplete seal may be desirable if coolant crosstalk between the passages 250 and 252 is desired to prevent stagnation. The second annular coolant passage 252 may terminate at the bottom with an external seal (not shown).

[0026] Figure 5 1 is a view showing the flow of coolant indicated by arrows through a passage formed by the cylinder liner 100 and the engine block 200 . Figure 5 The diagram in FIG. 2 is a flow diagram of the coolant flow path. Coolant enters one or more coolant passages 254 from one or more coolant flow passages in internal combustion engine 10. The coolant exits one or more coolant passages 254 and moves around the cylinder through first annular coolant passage 250 and second annular coolant passage 252 to exit through outlet 256. A similar coolant flow path exists on the opposite side of the diagram, where the coolant similarly exits one or more coolant passages 254 and moves around the cylinder through first annular coolant passage 250 and second annular coolant passage 252 to exit through outlet 256. Outlet 256 can be connected to allow coolant to exit and enter a second cylinder (not shown), where it can help cool one or more additional cylinders, or exit engine block 200, where it can help cool the cylinder head or be cooled and recirculated back into the cylinder.

[0027] Figure 6 is a cross-sectional view of the cylinder liner 100 housed in the engine block 200 . Figure 6It includes dashed lines to describe the height and position of the first annular coolant passage 250 and the second annular coolant passage 252 relative to the piston path between top dead center 350 and bottom dead center 358. The distance between top dead center 350 and bottom dead center 358 is shown by an enclosed line and can be referred to as the piston stroke 360. An enclosed line showing the distance between top dead center 350 and the top of the first passage 352 is also shown, and this distance can be referred to as the distance to the first passage 366. The top of the first passage 352 is closer to the top end 102 of the cylinder liner 100 than top dead center 350. Dashed lines are shown for the top (i.e., the top end of the first passage) 352 and the bottom (i.e., the bottom end of the first passage) 354 of the first passage. An enclosed line showing the height 362 of the first passage is shown. Similarly, a dashed line for the top (i.e., the top end of the second passage) 356 of the second passage is shown, and an enclosed line showing the height 364 of the second passage is shown. The bottom of the first passage 354 and the top of the second passage 356 are on the side of the annular ridge 112. Top dead center 350 is closer to the top end 102 of the cylinder liner 100 than the annular ridge 112.

[0028] Industrial Applicability

[0029] The disclosed cylinder liner or cylinder liner and engine block assembly can be used in any application where an increase in the reliability and operating life of the associated engine is desired. In the disclosed embodiment, the cylinder liner includes a first coolant passage and a second coolant passage. Due to the particularly close position of the first passage to the top of the cylinder, the coolant can achieve better access to the locations on the cylinder liner that are exposed to higher heat from combustion. The second passage can provide cooling to the remainder of the cylinder liner. Thus, the disclosed cylinder liner allows for the management and removal of heat generated during combustion without sacrificing the durability of the cylinder liner.

[0030] It should be understood that the foregoing description provides examples of the disclosed systems and techniques. However, it is contemplated that other implementations of the invention may differ in detail from the foregoing examples. All references to the invention or its examples are intended to refer to the specific example discussed at that point and are not intended to imply any limitation on the scope of the invention more generally. All language regarding differences and inconsistencies with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude them entirely from the scope of the invention unless otherwise specified.

Claims

1. An internal combustion engine, comprising: a cylinder head; a piston; and an engine block having a cylinder liner bore and a cylinder liner embedded in the cylinder liner bore, wherein a first annular coolant passage having a passage top end and a passage bottom end is formed between the cylinder liner bore and the cylinder liner, wherein the cylinder liner bore includes a cylinder liner bore ridge protruding from the cylinder liner bore and a cylinder liner bore groove recessed into the cylinder liner bore to form the widest part of the first annular coolant passage near the passage bottom end, and the cylinder liner includes: a cylindrical body having a central longitudinal axis, a cylinder bore for receiving the piston, the piston being slidably received within the cylinder bore for reciprocating movement along the central longitudinal axis between a top dead center position and a bottom dead center position, an annular ridge radially protruding from the cylindrical body relative to the central longitudinal axis, wherein the cylinder liner bore ridge protrudes radially towards the annular ridge, a top end having an annular flange, and a first cylindrical section of the cylindrical body spanning the length between the annular ridge and the annular flange, the first annular coolant passage being formed between the cylinder liner bore groove of the cylinder liner bore and the first cylindrical section, wherein when the piston is at the top dead center position, the passage top end is closer to the top end of the cylinder liner than the piston.

2. The internal combustion engine according to claim 1, wherein the top dead center position of the piston is at the side of the cylinder liner bore groove.

3. The internal combustion engine according to claim 1 or 2, wherein the cylinder liner and the cylinder liner bore form a second annular coolant passage below the first annular coolant passage.

4. The internal combustion engine according to claim 3, wherein the engine block includes a coolant passage configured to receive coolant from the cylinder head and supply the coolant into the first annular coolant passage and the second annular coolant passage.

5. The internal combustion engine according to claim 1 or 2, wherein the engine block includes a recessed area having an upward-facing shoulder, and the annular flange of the cylinder liner forms a sealing interface with the upward-facing shoulder, capable of retaining coolant in the first annular coolant passage, and the cylinder liner bore groove is provided between the cylinder liner bore ridge and the recessed area.

6. The internal combustion engine according to claim 5, wherein there is no secondary seal between the cylinder liner and the cylinder liner bore above the passage top end.

7. The internal combustion engine according to claim 1, wherein the annular ridge of the cylinder liner forms an interface with the cylinder liner bore ridge.

8. The internal combustion engine according to claim 7, wherein the cylinder liner forms a second annular coolant passage, and the interface is provided between the first annular coolant passage and the second annular coolant passage, and wherein the interface is configured to allow coolant crosstalk between the first annular coolant passage and the second annular coolant passage.

9. The internal combustion engine according to claim 7 or 8, wherein the top dead center position of the piston is closer to the top end of the cylinder liner than the annular ridge of the cylinder liner.

10. The internal combustion engine according to claim 9, wherein the top dead center position of the piston is above the annular ridge of the cylinder liner and closer to the top end of the cylinder liner than the annular ridge.

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