Oil squirter

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. An engine having a cylinder defined by a cylinder bore, a piston configured to reciprocate within the cylinder bore, and the oil squirter, along with a vehicle having such an engine, is also disclosed. In the engine, the first nozzle sprays oil onto the cylinder bore and the second nozzle sprays oil at the underside of the piston.

TECHNICAL FIELD

The present disclosure relates to an oil squirter.

BACKGROUND

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.

SUMMARY

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.

DETAILED DESCRIPTION

Referring to the drawings, wherein like reference numbers refer to like components,FIG. 1shows a schematic view of a motor vehicle10. The vehicle10incorporates a powertrain that includes an internal combustion (IC) engine12, such as a spark or a compression ignition type, adapted for driving wheels14and/or wheels16to propel the vehicle. The engine12applies its torque to the driven wheels14and/or16through a transmission18and via a drive or a propeller shaft20.

The engine12includes a cylinder block22and an oil pan or sump23. The sump23is attached to the cylinder block22for holding a body of oil. The cylinder block22houses a crankshaft24and cylinders26. Each cylinder26is defined by a cylinder bore27, and is provided with intake valves28and exhaust valves30that may be actuated by respective intake and exhaust camshafts32,34, as shown inFIG. 1. The intake valves28are configured to control supply of air or of air and fuel into the respective cylinder26, while the exhaust valves30are configured to control the removal of post combustion exhaust gas from the respective cylinder. Each cylinder26also includes a piston36and a connecting rod38. The pistons36are configured to reciprocate under the force of combustion inside their respective cylinder bores27, and thereby rotate the crankshaft24via the connecting rods38.

The crankshaft24, camshafts32,34, connecting rods38and various other rotating or otherwise frequently moving components of the engine12are 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 engine12also includes an oil pump40configured to draw oil from the sump23, and then pressurize and supply the oil to a main oil gallery42. The gallery42, in turn, distributes the pressurized oil to the engine bearings of the crankshaft24, camshafts32,34, connecting rods38, and to other components that rely on the oil for lubrication, actuation, and/or cooling. Because the engine12requires a greater pressure and volume of oil at higher engine speeds and combustion pressures, the pump40is configured to generate a progressive increase in the amount of oil pressure as the speed of the engine12rises. The pump40may be driven mechanically by the engine12, such as by the one of the camshafts32,34or the crankshaft24, or be operated electrically.

As shown inFIGS. 2-3, the engine12also includes oil squirters44. The oil squirters44are arranged on the cylinder block22, with one oil squirter positioned at each respective cylinder26underneath a respective piston36for selectively supplying a jet of oil to the underside of the piston and to the respective cylinder bore27. The oil squirters44are thereby employed to selectively reduce the thermal stress experienced by the pistons36as a result of combustion during operation of engine10and lubricate the cylinder bores27by generating a film of oil thereon. Although a single oil squirter44is shown at each cylinder26location, any quantity of oil squirters44may be used at each cylinder in other possible embodiments. The oil pressure generated by the pump40is sufficient for each oil squirter44to establish the jet of oil that targets the underside of the respective piston36and cylinder bore27.

Each oil squirter44includes a housing46. The housing46is in fluid communication with the pump40via an opening41to the gallery42. Each oil squirter44also includes a first nozzle48that is in fluid communication with the housing46and is configured to spray oil onto the respective cylinder bore27. Each oil squirter44additionally includes a second nozzle50that is in fluid communication with the housing46and is configured to spray oil at the underside of the respective piston36. Furthermore, each oil squirter44includes a mechanism52. The mechanism52is arranged within the housing46and is configured to open the first nozzle48and close the second nozzle50when the oil pressure within the gallery42is below a threshold value. The mechanism52is additionally configured to open the second nozzle50and close the first nozzle48when the oil pressure within the gallery42is 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 engine12. 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 bore27and the piston36, 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 engine12is lower than at higher engine speeds and loads, the noise generated due to the clearance between the piston36and the bore27may be objectionable. Therefore, at lower to medium engine speeds the first nozzle48is used to spray oil onto the respective cylinder bore27in order to take up the clearance between the piston36and the cylinder bore.

At higher engine speeds, such as at and above 3,000 RPM, the noise due to clearance between the bore27and the piston36may be overshadowed by the increase in the overall engine noise. Furthermore, the increased thermal energy being absorbed by the pistons36at higher engine speeds may be detrimental to the engine's reliability. Accordingly, at such higher engine speed, cooling of the pistons36may take precedence over engine noise concerns. Therefore, at higher engine speeds the first nozzle48is used to cool the underside of the respective piston36.

FIG. 2depicts the oil squirter44operating in a first mode where the first nozzle48sprays oil onto the respective cylinder bore27, whileFIG. 3depicts the oil squirter operating in a second mode where the second nozzle50sprays oil at the underside of the respective piston36. As shown inFIGS. 2 and 3, the mechanism52includes a piston54configured to remain in a first position (shown inFIG. 2) 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 piston54defines a fluid passage56.

The fluid passage56includes a first end58and second end60. The first end58is exposed to the first nozzle48and the second end60is exposed to the pump40via the gallery42. The fluid passage56is thereby configured to provide a first oil path62that is in fluid communication with the first nozzle48when the oil pressure is below the threshold value. Accordingly, the fluid passage56is configured to supply pressurized oil to the first nozzle48when the piston54is in the first position and be shut off when the piston is in the second position. The housing46, for its part, provides a second oil path64that is in fluid communication with the second nozzle50when the oil pressure is at or above the threshold value. As shown inFIGS. 2 and 3, the second oil path64is generated through the interior of the housing46when the piston54shifts to the second position and thereby uncovers the opening41. Accordingly, the second oil path64is configured to supply pressurized oil to the second nozzle50when the piston54resides in the second position.

The mechanism52also includes a spring66. The spring66is configured to preload the piston54to the first position and substantially close off the opening41when the oil pressure in the gallery42is below the threshold value. The spring62is additionally configured to permit the piston54to be shifted to the second position when the oil pressure in the gallery42is at or above the threshold value. To achieve such a response of the piston54, the spring constant “K” of the spring66is selected according to the area of the piston54exposed to the oil pressure in the gallery42. Therefore, the spring constant “K” of the spring66along with the area of the piston54ensure that the opening41remains closed by the piston54up to the threshold value of the oil pressure and be opened when the oil pressure reaches the threshold value. The mechanism52additionally includes a stopper68. The stopper68is configured to substantially block the fluid passage56and permit the pressurized oil from the gallery42to be directed to the second oil path64when the piston54is shifted to the second position. As shown inFIGS. 2 and 3, the stopper68may be formed integral with the housing46.

Overall, as disclosed, the oil squirter44is a dual mode mechanism. In its first mode of operation, the oil squirter44provides the ability to take up clearances between the respective cylinder bore27and piston36to 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 squirter44provides the ability to also cool the underside of the respective piston36at higher engine speeds to enhance reliability of the engine12.