Patent Application
20130019834
The present disclosure relates to an oil squirter.
Internal combustion (IC) engines, such as those used in motor vehicles, typically generate heat energy as a by-product of generating power. Generally, such engines are also cooled in order to maintain their operating temperature in a particular range and ensure the engine's efficient and reliable performance for propelling the subject motor vehicle.
In a majority of motor vehicles, IC engines are cooled by a circulating fluid, such as a specially formulated chemical compound mixed with water. Additionally, such engines are lubricated and cooled by oils that are generally derived from petroleum-based and non-petroleum synthesized chemical compounds.
Under extreme operating conditions, IC engines generate elevated amounts of heat energy within their combustion chambers. Such heat energy usually affects the entire engine structure, but is initially absorbed by the engine's pistons. In order to permit the pistons to reliably withstand elevated thermal stresses, IC engines are often equipped with oil squirters to cool the pistons.
An oil squirter includes a housing in fluid communication with a source of oil pressure, a first nozzle in fluid communication with the housing, and a second nozzle in fluid communication with the housing. The oil squirter also includes a mechanism arranged within the housing and configured to open the first nozzle and close the second nozzle when the oil pressure is below a threshold value. The mechanism is also configured to open the second nozzle and close the first nozzle when the oil pressure is at or above the threshold value.
The mechanism may include a piston configured to remain in a first position when the oil pressure is below the threshold value and be shifted by the oil pressure to a second position when the oil pressure is at or above the threshold value. The piston may define a fluid passage configured to supply oil to the first nozzle when the piston is in the first position and be shut off when the piston is in the second position.
The mechanism may also include a spring configured to preload the piston to the first position when the oil pressure is below the threshold value and permit the piston to be shifted to the second position when the oil pressure is at or above the threshold value.
The mechanism may additionally include a stopper configured to substantially block the passage when the piston is shifted to the second position. The stopper may be integral with the housing.
The fluid passage may include a first end and second end, such that the first end is exposed to the first nozzle, and the second end is exposed to the source of oil pressure.
The fluid passage may provide a first oil path in fluid communication with the first nozzle and the housing may provide a second oil path in fluid communication with the second nozzle.
An engine is disclosed having a cylinder defined by a cylinder bore, a piston configured to reciprocate within the cylinder bore, and the oil squirter. In the engine, the oil squirter's first nozzle sprays oil onto the cylinder bore and the second nozzle sprays oil at the underside of the piston. A vehicle having such an engine is also disclosed.
The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.
Referring to the drawings, wherein like reference numbers refer to like components,
The engine 12 includes a cylinder block 22 and an oil pan or sump 23. The sump 23 is attached to the cylinder block 22 for holding a body of oil. The cylinder block 22 houses a crankshaft 24 and cylinders 26. Each cylinder 26 is defined by a cylinder bore 27, and is provided with intake valves 28 and exhaust valves 30 that may be actuated by respective intake and exhaust camshafts 32, 34, as shown in
The crankshaft 24, camshafts 32, 34, connecting rods 38 and various other rotating or otherwise frequently moving components of the engine 12 are supported by specifically configured bearings (not shown). Typically, such bearings rely on a film of oil established between a surface of the bearing and the supported component to create a reliable low friction interface. Typically, the oil used in internal combustion engines is a specially formulated fluid that is derived from petroleum-based and non-petroleum chemical compounds. Such oil is mainly blended by using base oil composed of hydrocarbons and other chemical additives for a specific engine application.
The engine 12 also includes an oil pump 40 configured to draw oil from the sump 23, and then pressurize and supply the oil to a main oil gallery 42. The gallery 42, in turn, distributes the pressurized oil to the engine bearings of the crankshaft 24, camshafts 32, 34, connecting rods 38, and to other components that rely on the oil for lubrication, actuation, and/or cooling. Because the engine 12 requires a greater pressure and volume of oil at higher engine speeds and combustion pressures, the pump 40 is configured to generate a progressive increase in the amount of oil pressure as the speed of the engine 12 rises. The pump 40 may be driven mechanically by the engine 12, such as by the one of the camshafts 32, 34 or the crankshaft 24, or be operated electrically.
As shown in
Each oil squirter 44 includes a housing 46. The housing 46 is in fluid communication with the pump 40 via an opening 41 to the gallery 42. Each oil squirter 44 also includes a first nozzle 48 that is in fluid communication with the housing 46 and is configured to spray oil onto the respective cylinder bore 27. Each oil squirter 44 additionally includes a second nozzle 50 that is in fluid communication with the housing 46 and is configured to spray oil at the underside of the respective piston 36. Furthermore, each oil squirter 44 includes a mechanism 52. The mechanism 52 is arranged within the housing 46 and is configured to open the first nozzle 48 and close the second nozzle 50 when the oil pressure within the gallery 42 is below a threshold value. The mechanism 52 is additionally configured to open the second nozzle 50 and close the first nozzle 48 when the oil pressure within the gallery 42 is at or above the threshold value. The threshold value of oil pressure may be set, for example, at 20 Psi (138 KPa).
The threshold value of the oil pressure may be established empirically during development and testing of the engine 12. Accordingly, the threshold value may be set based on the engine speed below which it is desirable to reduce audible noise generated due to clearance between the bore 27 and the piston 36, as well as enhance lubrication there between. At lower to medium engine speeds, such as below 3,000 RPM, because the overall noise generated by the engine 12 is lower than at higher engine speeds and loads, the noise generated due to the clearance between the piston 36 and the bore 27 may be objectionable. Therefore, at lower to medium engine speeds the first nozzle 48 is used to spray oil onto the respective cylinder bore 27 in order to take up the clearance between the piston 36 and the cylinder bore.
At higher engine speeds, such as at and above 3,000 RPM, the noise due to clearance between the bore 27 and the piston 36 may be overshadowed by the increase in the overall engine noise. Furthermore, the increased thermal energy being absorbed by the pistons 36 at higher engine speeds may be detrimental to the engine's reliability. Accordingly, at such higher engine speed, cooling of the pistons 36 may take precedence over engine noise concerns. Therefore, at higher engine speeds the first nozzle 48 is used to cool the underside of the respective piston 36.
The fluid passage 56 includes a first end 58 and second end 60. The first end 58 is exposed to the first nozzle 48 and the second end 60 is exposed to the pump 40 via the gallery 42. The fluid passage 56 is thereby configured to provide a first oil path 62 that is in fluid communication with the first nozzle 48 when the oil pressure is below the threshold value. Accordingly, the fluid passage 56 is configured to supply pressurized oil to the first nozzle 48 when the piston 54 is in the first position and be shut off when the piston is in the second position. The housing 46, for its part, provides a second oil path 64 that is in fluid communication with the second nozzle 50 when the oil pressure is at or above the threshold value. As shown in
The mechanism 52 also includes a spring 66. The spring 66 is configured to preload the piston 54 to the first position and substantially close off the opening 41 when the oil pressure in the gallery 42 is below the threshold value. The spring 62 is additionally configured to permit the piston 54 to be shifted to the second position when the oil pressure in the gallery 42 is at or above the threshold value. To achieve such a response of the piston 54, the spring constant âKâ of the spring 66 is selected according to the area of the piston 54 exposed to the oil pressure in the gallery 42. Therefore, the spring constant âKâ of the spring 66 along with the area of the piston 54 ensure that the opening 41 remains closed by the piston 54 up to the threshold value of the oil pressure and be opened when the oil pressure reaches the threshold value. The mechanism 52 additionally includes a stopper 68. The stopper 68 is configured to substantially block the fluid passage 56 and permit the pressurized oil from the gallery 42 to be directed to the second oil path 64 when the piston 54 is shifted to the second position. As shown in
Overall, as disclosed, the oil squirter 44 is a dual mode mechanism. In its first mode of operation, the oil squirter 44 provides the ability to take up clearances between the respective cylinder bore 27 and piston 36 to reduce engine noise at lower engine speeds and increase lubrication of the piston and the cylinder bore. Additionally, in its second mode of operation, the oil squirter 44 provides the ability to also cool the underside of the respective piston 36 at higher engine speeds to enhance reliability of the engine 12.
While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.
