Oil supply device for engine

Abstract

An oil supply device for an engine includes a first oil suction passage, a second oil suction passage, a first pump for sucking and discharging oil from the first oil suction passage, a second pump arranged in series with the first pump, the second pump for sucking and discharging oil from at least one of the first pump and the second oil suction passage, a check valve for blocking oil circulation, a first oil passage, a second oil passage, a third oil passage for establishing communication between the first oil passage and the second oil passage, and a supply volume control device for varying oil supply volume to a lubrication system portion, to a cooling system portion, or to the lubrication system portion and the cooling system portion in accordance with a change in at least one of an engine oil temperature, an engine rotation speed, and an engine load.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is based on and claims priority under 35 U.S.C. §119 with respect to Japanese Patent Application No. 2004-281908 filed on Sep. 28, 2004, the entire content of which is incorporated herein by reference. FIELD OF THE INVENTION [0002] The present invention relates to an oil supply device for an engine. More particularly, the present invention pertains to an oil supply device for an engine, which supplies oil to lubrication system portions and cooling system portions of the engine. BACKGROUND [0003] A known oil supply device for an engine described in JPH04 (1992)-132414U includes a main oil pump (i.e., a first pump) and a motor driven oil pump (i.e., a second pump). According to the known oil supply device, a destination of oil from each pump is changed by appropriately switching oil passages from the both pumps on the basis of engine rotation speed. With the known oil supply device described in JPH04 (1992)-132414U, the f...

AI Technical Summary

Benefits of technology

[0008] In light of the foregoing, the present invention provides an oil supply device for an engine for supplying oil to a lubrication system portion and a cooling system portion of an engine, which includes a first oil suction passage in communication with an oil reservoir which reserves oil, a second oil suction passage in communication with the oil reservoir, a first pump for sucking oil from the first oil suction passage by means of rotation of crankshaft of the engine and for discharging the sucked oil, a second pump arranged in series with the first pump for controlling switching On-Off operation, the second pump configured to be supplied with oil discharged from the first pump and introduced from the second oil suction passage for sucking and discharging oil from at least one of the first p

Problems solved by technology

However, because whether it is necessary to supply oil to the lubrication system portions and the cooling system portions is varied in accordance with temperature of oil and spattered volume of oil (amount of oil mist) and further because there is adequacy of an oil pump used for supplying oil to each portion (e.g., a pump with larger output torque is required when oil viscosity is higher), oil cannot be supplied appropriately to the lubrication system portion and the cooling system portion with known oil supply devices where oil passages are switched on the basis of only the engine rotation speed.

Further, with the construction of the oil supply device according to JPH04 (1992)-132414U, because the main oil pump and the electric oil pump are arranged in parallel to the destination of the oil, there is an drawback that the both pumps should be high output pumps when it is necessary to supply oil by high pressure relative to the destination of the oil.

Further, with the construction of the oil supply device according to JPH10 (1998)-252434, the second pump cannot suck oil unless the first pump is operated, and thus the second pump cannot supply the oil to the destination of the oil.

Particularly, there is a drawback that oil cannot be supplied from the second pump to the destination of the oil until the first pump sufficiently sucks oil and discharge the oil to the second pump at an engine start.

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