Cooling block for multi-cylinder air compressor

Abstract

A cooling block for cooling a piston of a multi-cylinder air compressor is disclosed. The cooling block may include a body including a first end and a second end on opposite sides of the body. The cooling block may also include a first cooling nozzle near the first end and a second cooling nozzle near the second end. The first cooling nozzle and the second cooling nozzle may each include a hole through which a coolant is sprayed into a crankcase of the multi-cylinder air compressor.

Description

Technical Field

[0001] The present invention relates generally to piston cooling systems for air compressors, and more particularly to cooling blocks for cooling pistons of multi-cylinder air compressors used in armored vehicles. Background Art

[0002] A multi-cylinder air compressor includes two or more cylinders, each with a piston in it, which reciprocates to produce compressed air. For example, a two-cylinder air compressor includes a crankcase that houses a crankshaft, two cylinders, and two connecting rods, each of which is mounted on the crankshaft at one end and connected to one of the pistons at the other end. As the crankshaft rotates, the connecting rod moves the piston up and down within the cylinder. In operation, as the piston moves downward, air is drawn into the cylinder and a partial vacuum is created in the cylinder. Subsequently, as the piston moves upward and increases the pressure in the cylinder, the air is compressed and pushed out of the cylinder. The compressed air thus produced can be collected in a tank and stored for various uses.

[0003] Multi-cylinder air compressors can be used in compressed air supply systems for applications that require large amounts of compressed air. For example, a two-cylinder air compressor can be used to meet the high compressed air needs of the air brakes and central tire inflation system of an eight-wheel drive armored fighting vehicle. In this example, the two-cylinder air compressor can be connected to and driven by the engine of the fighting vehicle. However, due to the high demands on the compressor and the high temperature environment created in the space around the compressor by the engine running in the vehicle, the air compressor piston used in such an application may overheat and seize. Therefore, without an effective piston cooling system, the piston in such an application may have a low duty cycle, or a period of use before the piston overheats.

[0004] U.S. Patent No. 8,317,488 describes a dry-running (or oil-free) multi-cylinder air compressor having a device for generating cooling air flowing through the interior of a crankcase. The air compressor described therein includes two cylinders and two pistons, each piston being associated with one cylinder and operating in a separate chamber of the compressor. The cooling air flow is generated by the movement cycle of the pistons and flows through the interior of the crankcase to maintain the compressor at a subcritical temperature. Specifically, as the pistons reciprocate, cooling air is drawn into the crankcase through a separate intake valve at the top of the compressor near the intake pipe.

[0005] Although effective, there remains a need for improved piston cooling system designs for multi-cylinder air compressors used in applications having high compressed air demands, such as combat vehicle applications. Summary of the invention

[0006] According to one aspect of the present invention, a cooling block for cooling the piston of a multi-cylinder air compressor is disclosed. The cooling block may include a main body including a first end and a second end on opposite sides of the main body. The cooling block may further include a coolant inlet, and a first cooling nozzle near the first end, the first nozzle having a first hole, through which the coolant is sprayed into the crankcase of the multi-cylinder air compressor. The cooling block may further include a second cooling nozzle near the second end, the second cooling nozzle having a second hole, through which the coolant is sprayed into the crankcase. In addition, the cooling block may further include an internal conduit extending through the main body and configured to transport coolant from the coolant inlet to each of the first and second cooling nozzles.

[0007] According to another aspect of the present invention, an engine and air compressor system for an armored vehicle is disclosed. The engine and air compressor system may include an engine that is an inline six-cylinder diesel engine. The engine and air compressor system may further include a two-cylinder air compressor, connected to the engine and driven by the engine, and configured to supply compressed air to operate the central tire inflation system of the armored vehicle. The two-cylinder air compressor may include a crankcase with a bottom, a crankshaft rotatably mounted in the crankcase, two connecting rods mounted on the crankshaft, two cylinders mounted in the crankcase, and a piston arranged in a corresponding one of the two cylinders at the end of the corresponding one of the two connecting rods. The engine and air compressor system may also include a first cooling block and a second cooling block, both connected to the bottom of the crankcase, and configured to spray a coolant into the crankcase to cool the piston. Each of the first cooling block and the second cooling block may include a coolant inlet, a first cooling nozzle having a first hole, through which the coolant is sprayed into the crankcase, and a second cooling nozzle having a second hole, through which the coolant is sprayed into the crankcase.

[0008] According to another aspect of the present invention, a two-cylinder air compressor for an armored vehicle is disclosed. The two-cylinder air compressor may include a crankcase, a crankshaft rotatably mounted in the crankcase, two connecting rods mounted on the crankshaft, two cylinders mounted in the crankcase, and two pistons, each piston being arranged in a corresponding one of the two cylinders at the end of a corresponding one of the two connecting rods. The two-cylinder air compressor may further include: a first cooling block connected to the bottom of the crankcase and configured to spray coolant into one of the two pistons, and a second cooling block connected to the bottom of the crankcase and configured to spray coolant into the other of the two pistons. The first cooling block and the second cooling block may each include a first cooling nozzle having a first hole, through which the coolant is sprayed, and a second cooling nozzle having a second hole, through which the coolant is sprayed.

[0009] These and other aspects and features of the present invention will be more readily understood when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a perspective view of an armored vehicle constructed in accordance with the present invention.

[0011] Figure 2 is a schematic diagram of a central tire inflation system for an armored vehicle according to the present invention.

[0012] Figure 3 is a perspective view of an engine and compressor system for an armored vehicle constructed in accordance with the present invention, the engine and compressor system including an engine connected to a two-cylinder air compressor.

[0013] Figure 4 is a partial cross-sectional view of a two-cylinder air compressor shown alone constructed in accordance with the present invention.

[0014] Figure 5 is a perspective view of one of the cooling blocks for a twin cylinder air compressor constructed in accordance with the present invention.

[0015] Figure 6 The invention is constructed through Figure 5 Cross-sectional view of section 6-6.

[0016] Figure 7 is a perspective view of a cooling block assembled with a twin cylinder air compressor constructed in accordance with the present invention.

[0017] Figure 8 It passes through Figure 7 A cross-sectional view of section 8-8 showing the flow of coolant from a cooling block to a crankcase of a twin-cylinder air compressor constructed in accordance with the present invention.

[0018] Fig. 9 is a side cross-sectional view showing the flow of coolant from one of the cooling blocks to the crankcase constructed in accordance with the present invention.

[0019] Fig.10 is an exploded view of the assembly of a twin cylinder air compressor and a cooling block constructed in accordance with the present invention.

[0020] Fig.11 is a flow chart of a series of steps of a method according to the present invention that may involve assembling a cooling block with a twin cylinder air compressor and using the cooling block to cool the pistons of the air compressor. DETAILED DESCRIPTION

[0021] Referring now to the drawings, and in particular to Figure 1 , an armored vehicle 10 is shown. In one example, the armored vehicle 10 may be an armored fighting vehicle. The vehicle 10 may include an engine 12 (see also Figure 3), the engine may be a high horsepower inline six-cylinder diesel engine in which the engine cylinders are mounted in a straight line and all pistons drive a common crankshaft. The engine 12 may have a brake horsepower (bhp) ranging from 350 bhp to 800 bhp. The vehicle 10 may further include wheels 14 driven by the engine 12, such as eight wheels 14. In one example, the vehicle 10 may be an eight-wheel drive vehicle in which all eight wheels 14 are driven by the engine 12. The inflation and deflation of the tires 16 of the wheels 14 may be controlled by a central tire inflation system 18 (see Figure 2 As described in further detail below, a multi-cylinder air compressor 20 may be coupled to the engine 12 (see Figure 3 ), and can be used to supply compressed air to operate the central tire inflation system 18 and the air brakes of the vehicle 10.

[0022] Central tire inflation system 18 Figure 2 14 . As will be appreciated by those skilled in the art, the central tire inflation system 18 may include a wheel valve 22 associated with each wheel 14, an operator control panel 24, an electronic control unit (ECU) 26, and a pneumatic control unit (PCU) 28 (which controls the wheel valves 22 and monitors the pressure of the tires 16). In operation, the driver may input a desired tire pressure pattern to match the operating conditions. The ECU 26 may monitor the tire pressure (via a signal from the PCU 28) and transmit commands to the PCU 28 to inflate and deflate the tires 16 as needed to match the driver's commands. The central tire inflation system 18 may function to improve the performance of the tires 16 under different operating conditions. For example, the central tire inflation system 18 may partially deflate the tires 16 in certain off-road situations, and may inflate the tires 16 at high vehicle speeds.

[0023] Now turn to Figure 3 , an engine and compressor system 30 of the vehicle 10 is shown. The engine and compressor system 30 may include the engine 12 and the multi-cylinder air compressor 20. The multi-cylinder air compressor 20 may be bolted to the engine 12 and may be gear driven by the engine 12. The multi-cylinder air compressor 20 may include a crankcase 32 and two or more cylinders 34, each cylinder having a piston 36 that reciprocates therein to produce compressed air (see also Figure 4 ). In one arrangement, the multi-cylinder air compressor 20 may be a dual cylinder air compressor 38 having two cylinders 34. The compressed air produced by the multi-cylinder air compressor 20 may be delivered to a compressed air tank that supplies compressed air as needed during vehicle operation to operate the air brakes and the central tire inflation system 18.

[0024] Mounted to the bottom 40 of the crankcase 32 may be two or more cooling blocks for cooling the piston 36. For example, a two-cylinder air compressor 38 may have a first cooling block 42 and a second cooling block 44 configured to deliver coolant to the interior of the crankcase 32 to cool the piston 36. The first cooling block 42 may deliver coolant to one of the cylinders 34, and the second cooling block 44 may deliver coolant to the other of the two cylinders 34. The coolant may be oil supplied by the engine 12 or from another source. The applicant has found that the use of two cooling blocks 42 and 44 allows the piston 36 of the two-cylinder air compressor 38 to operate continuously (continuous working cycle) without overheating or seizing. In air compressor designs with more than two cylinders, more cooling blocks may be used, each cooling block delivering coolant to each cylinder.

[0025] exist Figure 4 1 and 2. The twin cylinder air compressor 38 is shown in more detail in FIG. The crankcase 32 may include a crankshaft 46 rotatably mounted therein and driven to rotate by the engine 12. In addition, two connecting rods 48 may each be mounted on the crankshaft 46 at one end and coupled to one of the two pistons 36 at the other end. In this way, the rotation of the crankshaft 46 may drive the reciprocating motion of the pistons 36 in the cylinders 34. As the pistons 36 move downward in their respective cylinders 34, a partial vacuum may be created that draws air into the cylinders 34. As the pistons 36 move upward, the pressure increases to produce compressed air and expel the compressed air out of the cylinders 34 to be collected in a compressed air tank.

[0026] exist Figure 5-6 4. The first cooling block 42 is shown separately in FIG. The second cooling block 44 is identical to the first cooling block 42 and is therefore not shown. The cooling block 42 may have a body 50 formed of cast iron or other suitable material. The body 50 may include a coolant inlet 52 through which coolant is received from the engine 12. In one arrangement, the cooling block 42 may have two of the inlets 52 (see FIG. Figure 6 ), the inlet 52 that does not receive coolant during operation is blocked. In addition, the body 50 may have a first end 54 and a second end 56 on opposite sides of the body 50. Near the first end 54 may be a first cooling nozzle 58, and near the second end 56 may be a second cooling nozzle 60. The first cooling nozzle 58 may include a first hole 62 through which coolant is injected into the crankcase 32, and the second cooling nozzle 60 may include a second cooling hole 64 through which coolant is injected into the crankcase 32 (see Figure 6 The internal conduit 66 can deliver coolant from the coolant inlet 52 to each of the first cooling nozzle 58 and the second cooling nozzle 60 (see Figure 6). Applicants have found that using two cooling nozzles on each cooling block 42 and 44, as opposed to one cooling nozzle, provides a continuous piston duty cycle in which the pistons operate continuously without overheating. Alternative arrangements may include more than two cooling nozzles on each cooling block.

[0027] Each of the first cooling jet 58 and the second cooling jet 60 may include a raised portion 68 extending from the body 50, wherein the first and second holes 62 and 64 are located at a top 70 of the respective raised portion 68. The raised portion 68 is used to raise the first hole 62 and the second hole 64 above a pool of oil that may collect at the bottom of the crankcase 32 (see, for example, Fig. 9 ), thereby spraying coolant above the oil pool. In one arrangement, the raised portion 68 has a height (h) of approximately 7 mm, although the height of the raised portion 68 may vary depending on the design of the air compressor 38. The first nozzle 58 and the second nozzle 60 may be spaced a certain distance apart so that the nozzles 58 and 60 are positioned on opposite sides of the crankshaft 46 at certain times during the rotation of the crankshaft 46 (see also Figure 8-9 and more details below). This allows the nozzles 58 and 60 to spray coolant through the crankshaft 46 to impinge on the piston 36. In one exemplary arrangement, the first nozzle 58 and the second nozzle 60 are spaced approximately 56 millimeters from each other.

[0028] Additionally, a passage 72 may extend through each raised portion 68 and provide fluid communication between the internal conduit 66 and the apertures 62 and 64 (see FIG. Fig. 9 ). In this way, coolant can flow from the internal conduit 66 into the channel 72 and can exit the nozzles 58 and 60 through the corresponding holes 62 and 64. In one arrangement, the holes 62 and 64 (and the channel 72) can each have a diameter of about 0.8 mm. However, in alternative designs, the diameters of the holes 62 and 64 (and the channel 72) may deviate from this.

[0029] The cooling block 42 may have a rectangular shape with a length (l) greater than its width (w). In one arrangement, the length (l) of the cooling block 42 may be approximately 103 mm and the width (w) of the cooling block 42 may be approximately 54 mm. However, the size and shape of the cooling block 42 may vary depending on the design of the air compressor 38 or other considerations. The cooling block 42 may further include one or more bolt holes 74 for bolting the cooling block 42 to the bottom of the air compressor 38 (see FIG. Fig.10 and more details below). In alternative arrangements, the cooling block 42 may have additional or alternative features to facilitate its connection to the air compressor 38.

[0030] Reference Figure 7, coolant may be supplied to the cooling block 42 via one or more coolant supply lines 76 extending from the engine 12. Although for clarity in FIG. Figure 7 Not shown, the second cooling block 44 may receive coolant in a similar manner from the supply line 76 or a different supply line.

[0031] The flow of coolant 78 through holes 62 and 64 and into crankcase 32 is as follows: Figure 8-9 The first cooling block 42 may supply the coolant 78 to one of the pistons 36 of one of the two cylinders 34, and the second cooling block 44 may supply the coolant 78 to the other piston 36 of the other of the two cylinders 34 (see Figure 8 ). The first hole 62 and the second hole 64 of each of the cooling blocks 42 and 44 can be spaced apart so that the coolant 78 can flow through the crankshaft 46 and both coolant flows impinge on the piston 36 at some rotation angles of the crankshaft 46. (See Figure 8-9 ). At some rotational angles of the crankshaft 46, one of the coolant flows from one of the holes 62 and 64 may be at least partially blocked by the crankshaft 46. However, the cooling blocks 42 and 44 may deliver sufficient coolant to the piston 36 so that the piston is 100% covered with coolant regardless of the rotational angle of the crankshaft 46. At a coolant pressure of approximately 40 psi, the cooling blocks 42 and 44 may spray coolant 78 into the crankcase 32 at a flow rate of approximately 27 milliliters (mL) per second. However, this flow rate may deviate depending on the pressure of the coolant, the design of the cooling blocks 42 and 44, and other factors. In addition, as described above, the raised portion 68 of the first cooling nozzle 58 and the second cooling nozzle 60 may allow coolant to be sprayed to clear any oil that may collect on the bottom 40 of the crankcase 32 (see Fig. 9 ).

[0032] The first cooling block 42 and the second cooling block 44 are assembled with the dual-cylinder air compressor 38. Fig.10 . Before assembling the air compressor 38 with the cooling blocks 42 and 44, the cover (not shown) on the bottom 40 of the crankcase 32 may be removed. The bottom 40 of the crankcase 32 may have receiving holes 80 aligned with the bolt holes 74 of the cooling blocks 42 and 44 to receive bolts 82 that secure the cooling blocks 42 and 44 to the two-cylinder air compressor 38. Other means for securing the cooling blocks 42 and 44 to the air compressor 38 may be used in alternative arrangements. The bottom 40 of the air compressor 38 may have holes 84 that accommodate the first cooling nozzle 58 and the second cooling nozzle 60 to allow the first cooling nozzle 58 and the second cooling nozzle 60 to be inserted into the interior of the crankcase 32 (see Figure 8-9 ).

[0033] Although shown and described for use in an armored vehicle, the cooling blocks disclosed herein may be used to supply coolant to the pistons of multi-cylinder air compressors used in various other applications having high compressed air demands, such as, but not limited to, utility vehicles or railroad vehicles.

[0034] Industrial Applicability

[0035] Generally, the teachings of the present invention may find utility in many industries, including but not limited to the combat vehicle industry. More specifically, the teachings of the present invention may find utility in any industry that uses multi-cylinder air compressors to meet high compressed air demands.

[0036] Fig.11 1 and 2. A series of steps are shown that may be involved in assembling the cooling blocks 42 and 44 with the two-cylinder air compressor 38 and using the cooling blocks 42 and 44 to cool the pistons 36 of the air compressor 38. After the bottom cover of the two-cylinder air compressor 38 is removed from the crankcase 32, the first and second cooling blocks 42 and 44 may be connected to the bottom 40 of the crankcase 32, such as by bolting the cooling blocks 42 and 44 to the crankcase 32 (blocks 100 and 110; see Fig.10 ). According to block 120, the engine and air compressor system 30 may be assembled by mounting the two-cylinder air compressor 38 to the engine 12 and connecting the cooling blocks 42 and 44 to the coolant supply line 76. The thus assembled engine and air compressor system 30 may be installed to the vehicle 10 if not already installed to the vehicle 10. Blocks 100, 110, and 120 may be performed in various orders.

[0037] During operation of the vehicle 10, the coolant 78 supplied by the engine 12 may be injected through the first and second orifices 62, 64 of each of the first and second cooling nozzles 58, 60 (block 130; see Figure 8-9 ). The coolant 78 may then impinge on the pistons 36 (block 140), with each of the cooling blocks 42 and 44 providing coolant to one of the pistons 36. Regardless of the rotational angle of the crankshaft 46, the coolant 78 may be sprayed across the crankshaft 46 and cover 100% of the pistons 36. Fig.11 The method can be correspondingly applied to a multi-cylinder air compressor having more than two cylinders.

[0038] The cooling block disclosed herein is designed to cool the piston of a multi-cylinder air compressor. Each cooling block includes at least two cooling nozzles, and the at least two cooling nozzles are configured to spray coolant onto one cylinder of the multi-cylinder air compressor. The cooling nozzles are spaced apart so that the coolant can flow through the crankshaft of the air compressor at all rotation angles of the crankshaft. At certain rotation angles of the crankshaft, the coolant from both cooling nozzles can flow through the crankshaft and hit the piston. At other rotation angles of the crankshaft, the coolant from one of the cooling nozzles can flow through the crankshaft and hit the piston, and the coolant flow from the other cooling nozzle may be blocked or at least partially blocked. However, regardless of the rotation angle of the crankshaft, the piston of each cylinder is always completely covered by the coolant. The cooling block disclosed herein increases the duty cycle of the piston, thereby allowing the piston to run continuously and better meet the needs of the air compressor.

Claims

1. A piston cooling system, comprising: Multi-cylinder air compressor; and A cooling block for cooling the piston of the multi-cylinder air compressor, the cooling block comprising: Coolant inlet; a first cooling nozzle having a first hole through which coolant is injected into a crankcase of the multi-cylinder air compressor; a second cooling nozzle having a second hole through which coolant is injected into the crankcase, The cooling block is mounted to the bottom of the crankcase, and the coolant inlet is located outside the crankcase.

2. The system according to claim 1, wherein: The second cooling nozzle is spaced apart from the first cooling nozzle to define a horizontal direction, and wherein each of the first cooling nozzle and the second cooling nozzle comprises: a raised portion protruding away from the main body of the cooling block in a vertical direction, the first hole and the second hole being at top portions of the corresponding raised portions in the vertical direction; and A passage extends through the raised portion and provides fluid communication between an internal conduit within the cooling block and a corresponding first or second aperture.

3. The system of claim 2, wherein the raised portion has a height of 7 mm.

4. The system of claim 1, wherein the first and second holes are spaced 56 millimeters apart.

5. The system of claim 1, wherein each of the first and second holes has a diameter of 0.8 mm.

6. The system of claim 1, wherein the cooling block includes bolt holes for bolting the cooling block to a bottom of the crankcase. 7 . The system of claim 1 , wherein each of the first cooling nozzle and the second cooling nozzle is configured to inject the coolant into one cylinder of the multi-cylinder air compressor through a crankshaft when the cooling block is connected to the multi-cylinder air compressor.

8. The system of claim 1, further comprising: a body including a first end and a second end, the first end and the second end being on opposite sides of the body; The first cooling nozzle is closer to the first end than to the second end; The second cooling nozzle is closer to the second end than to the first end; and An internal conduit extends through the body and is configured to deliver the coolant from the coolant inlet to each of the first cooling nozzle and the second cooling nozzle.

9. The system according to claim 1, wherein: The multi-cylinder air compressor is a liquid-cooled multi-cylinder air compressor.

10. An engine and air compressor system for a vehicle, comprising: engine; a two-cylinder air compressor connected to and driven by the engine and configured to supply compressed air, the two-cylinder air compressor comprising a crankcase having a bottom, a crankshaft rotatably mounted in the crankcase, two connecting rods mounted on the crankshaft, two cylinders mounted in the crankcase, and two pistons, each piston being disposed in a corresponding one of the two cylinders at an end of a corresponding one of the two connecting rods; and The first cooling block and the second cooling block are both connected to the bottom of the crankcase and configured to spray coolant into the crankcase to cool the piston. The first cooling block and the second cooling block each include: Coolant inlet, a first cooling nozzle having a first hole through which the coolant is injected into the crankcase, a second cooling nozzle having a second hole through which the coolant is sprayed into the crankcase, the second cooling nozzle being spaced apart from the first cooling nozzle to define a horizontal direction, each of the first cooling nozzle and the second cooling nozzle comprising a raised portion that protrudes away from the body of the cooling block in a vertical direction, the first hole and the second hole being at a top portion of the corresponding raised portion in the vertical direction; and a passage extending through the raised portion and providing fluid communication between an internal conduit within the cooling block and a corresponding first or second aperture, The first cooling block and the second cooling block have the coolant inlet located outside the crankcase.

11. The engine and air compressor system of claim 10, wherein the first cooling block and the second cooling block allow the piston to operate continuously.

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