OIL PUMP SYSTEM FOR VEHICLE

Abstract

The present disclosure provides an oil pump system for a vehicle to control an oil flow or a flow rate of oil according to characteristics of an oil flow rate consumed for each component. The oil pump system includes: a mechanical oil pump, an electrical oil pump. In particular, the mechanical oil pump supplies oil to a lubrication component, and the electrical oil pump supplies oil to a cooling component or a control component. The mechanical oil pump and the electrical oil pump are independently operated.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to Korean Patent Application No. 10-2015-0141744, filed on Oct. 8, 2015, which is incorporated herein in its entirety by reference.

FIELD

The present disclosure relates to an oil pump system for a vehicle.

BACKGROUND

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

Recently, as part of preparation for depletion of fossil fuel and environmental pollution, eco-friendly vehicles such as a hybrid vehicle using both an engine using fossil fuel and an electric motor operated by electricity, as driving sources, have been developed and come onto the market.

An oil pump is installed in a transmission of a hybrid vehicle and configured to supply oil to lubricate a lubrication element (e.g., an element to be lubricated, such as bearing, bush, gear, etc.), cool a cooled element (e.g., an element to be cooled, such as an electric motor, an engine, or a supplemental cooling device for cooling the motor, engine etc.), and form control pressure for a control element (e.g., a clutch, a brake, etc.).

Meanwhile, flow rate characteristics of oil consumed for each element vary depending on operational conditions of a vehicle, or the like. For example, a supply flow rate of oil desired for lubricating a lubrication element may be increased in proportion to a vehicle speed, and a supply flow rate of oil desired for cooling a cooled element may be increased when torque of an electric motor is high under hill climbing/acceleration conditions of a vehicle. A supply flow rate of oil desired for forming control pressure of a control element may be significantly increased when a speed is changed.

In the oil pump system, some hybrid vehicles use a mechanical oil pump and an electrical oil pump connected in parallel. Here, the mechanical oil pump is configured to supply oil to a lubrication element, a cooled element, and a control element, and when a supply flow rate of oil by the mechanical oil pump is insufficient such as in an idle state of the vehicle or a low speed section, the electrical oil pump serves to adjunctively supply oil.

However, in the related art oil pump system, since the electrical oil pump adjunctively operates and the mechanical oil pump operates as a main oil supplier, the mechanical oil pump needs an increased pump capacity and thus its size may be increased.

Also, since the mechanical oil pump is configured to be directly connected to a driving source (e.g., an engine or an electric motor) and rotated, a supply flow rate of oil may be increased as revolution per minute (RPM) of the driving source is increased. We have discovered that when a supply flow rate of oil is increased and higher than a flow rate desired for a transmission according to an increase in a vehicle speed, power of the driving source may be wasted and the fuel efficiency of the vehicle decreases.

In the related art, an oil pump system employing only an electrical oil pump alone, without a mechanical oil pump, has been developed.

In the oil pump system employing only the electrical oil pump alone, the electrical oil pump may be controlled to appropriately cope with a supply flow rate of oil desired for a transmission, reducing a waste of oil, and since a mechanical oil pump is omitted, fuel efficiency may be enhanced.

We have discovered, however, that since oil should be constantly supplied to a lubrication element, significant energy loss occurs when electric energy is converted into mechanical energy in the electrical oil pump, and in addition, when the electrical oil pump is operated under an extremely low temperature (e.g., −35° C.), oil itself acts as a large load, an undesired large motor for driving the electrical oil pump is requireded.

SUMMARY

The present disclosure provides an oil pump system for a vehicle, in which a mechanical oil pump is configured to supply oil toward a lubrication element and an electrical oil pump is configured to supply oil toward a cooled element and a control element, and the mechanical oil pump and the electrical oil pump are independently driven to optimally control an oil flow or a flow rate of oil according to characteristics of an oil flow rate desired for each of the elements.

According to an exemplary form of the present disclosure, an oil pump system for a vehicle includes: a mechanical oil pump configured to supply oil to a lubrication element; and an electrical oil pump configured to supply oil to at least any one of a cooled element and a control element, wherein the mechanical oil pump and the electrical oil pump are independently operated.

A first oil flow channel for supplying oil toward the lubrication element may be connected to the mechanical oil pump.

The mechanical oil pump may be connected to a driving source of a vehicle so as to be operated.

A second oil flow channel for supplying oil toward the control element may be connected to the electrical oil pump.

A third oil flow channel for supplying oil toward the cooled element may be connected to one side of the second oil flow channel.

A regulator valve may be installed in a portion where the second oil flow channel and the third oil flow channel are connected.

According to another exemplary form of the present disclosure, an oil pump system for a vehicle includes: an oil pan configured to store oil; a mechanical oil pump configured to supply oil of the oil pan only to a lubrication element; and an electrical oil pump configured to supply oil of the oil pan to at least any one of a cooled element and a control element, wherein the mechanical oil pump and the electrical oil pump are independently connected to the oil pan.

A first intake line may be connected to an inlet of the mechanical oil pump, the first intake line may be connected to the oil pan, and a first oil line supplying oil to the lubrication element may be connected to an outlet of the mechanical oil pump.

A second intake line may be connected to an inlet of the electrical oil pump, the second intake line may be connected to the oil pan, and a second oil line supplying oil to the control element may be connected to an outlet of the electrical oil pump.

The first intake line and the second intake line may be independently connected to the oil pan.

A third oil flow channel supplying oil toward the cooled element may be connected to one side of the second oil flow channel, and a regulator valve may be installed in a portion where the second oil flow channel and the third oil flow channel are connected.

Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

FIG. 1 is a view illustrating an oil pump system for a vehicle;

FIG. 2 is a diagram illustrating an oil pump system for a vehicle;

FIG. 3 is a diagram illustrating a transmission of a hybrid vehicle to which an oil pump system for a vehicle is applicable; and

FIG. 4 is a graph illustrating a relationship between an oil flow rate of an electric oil pump of an oil pump system for a vehicle and a vehicle speed.

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

For reference, dimensions of elements or thicknesses of lines illustrated in the drawings referred to describe the present disclosure may be exaggerated for the convenience of understanding. Also, the terms used henceforth have been defined in consideration of the functions of the present disclosure, and may be altered according to the intent of a user or operator, or conventional practice. Therefore, the terms should be defined on the basis of the entire content of this specification.

Referring to FIGS. 1 and 2, an oil pump system for a vehicle according to an exemplary form of the present disclosure includes: an oil pan 15 storing oil, a mechanical oil pump 11 supplying oil to a lubrication element 21, and an electrical oil pump 12 configured to supply oil to at least one of a control element 22 or a cooled element 23.

The mechanical oil pump 11 is configured to pump oil of the oil pan 15 and supply the oil toward the lubrication element 21. Here, the lubrication element 21 refers to a component making a motion relative to a peripheral component and thus generating frictional abrasion and heat, such as a bearing, a bush, and a gear.

As illustrated in FIG. 1, the mechanical oil pump 11 is connected to a driving source 1 such as an engine or an electric motor of a vehicle, and thus the mechanical oil pump 11 operates as the driving source 1 of the vehicle is driven,. The mechanical oil pump 11 may increase a supply flow rate of oil in proportion to a vehicle speed. In other words, the supply flow rate of oil increases according to the increase of the vehicle speed.

In particular, since the mechanical oil pump 11 is configured to supply oil only toward the lubrication element 21 (e.g., a bush, a bearing, gears), oil may be supplied according to a desired flow rate of the lubrication element 21, and thus, a waste of oil may be reduced even at high RPM of the driving source 1 (e.g., an engine or a motor), and thus the fuel efficiency of the vehicle and the efficiency of the lubrication on the lubrication element 21 are improved.

A first oil flow channel 31 for supplying oil toward the lubrication element 21 (e.g., a bush, a bearing, gears) may be connected to the mechanical oil pump 11, and a relief valve 31 a may be installed on one side of the first oil flow channel 31.

A first intake line 41 may be connected to an inlet of the mechanical oil pump 11 and connected to the oil pan 15, and the first oil flow channel 31 is connected to an outlet of the mechanical oil pump 11. Thus, the mechanical oil pump 11 may intake oil of the oil pan 15 through the first intake line 41 and subsequently supply oil toward the lubrication element 21 through the first oil flow channel 31.

The electronic oil pump 12 is configured to pump oil from the oil pan 15 and supply the oil to the control element 22 and/or the cooled element 23. Here, the control element 22 may be a clutch or a brake operated by oil which is supplied or discharged thereto, and the cooled element 23 may be a driving source of a hybrid vehicle or an electric vehicle (e.g. a motor or an engine), an additional cooling device for cooling an electric motor or engine, or the like.

As illustrated in FIGS. 1 and 2, a motor 16 is connected to the electrical oil pump 12, and the electrical oil pump 12 is operated by the motor 16. A controller (not shown) calculates a supply flow rate of oil desired for forming control pressure of the control element 22 and/or cooling the cooled element 23 and subsequently controls the motor 16 according to the flow rate desired for the control element 22 and/or the cooled element 23, whereby the electrical oil pump 12 may supply an appropriate amount of oil corresponding to the flow rate desired for the control element 22 and/or the cooled element 23.

For example, the electrical oil pump 12 may be independently driven by the motor 16 to control a supply flow rate of oil, regardless of the driving source 1 of the vehicle, and thus, formation of control pressure of the control element 22 and/or cooling of the cooled element 23 may be stably and independently performed regardless of a vehicle speed.

A second oil flow channel 32 for supplying oil toward the control element 22 is connected to the electrical oil pump 12, and a third oil flow channel 33 for supplying oil toward the cooled element 23 is connected to one side of the second oil flow channel 32.

In particular, a regulator valve 34 for forming control pressure of the control element 22 may be installed in a portion where the second oil flow channel 32 and the third oil flow channel 33 are connected. When oil is supplied to the control element 22 through the second oil flow channel 32 according to an operation of the electrical oil pump 12, control pressure of the control element 22 may be formed by the regulator valve 34, and after the control pressure is formed, oil may flow to the third oil flow channel 33 so as to be supplied toward the cooled element 23. A relief valve 33a may be installed on one side of the third oil flow channel 33.

As described above, the electrical oil pump 12 may control a supply flow rate or a flow of oil by controlling the motor 16 or the regulator valve 34 regardless of a vehicle speed, and thus, the electrical oil pump 12 may appropriately supply oil according to a desired flow rate of the control element 22 and/or the cooled element 23.

A second intake line 42 is connected to an inlet of the electrical oil pump 12 and connected to the oil pan 15, and the second oil flow channel 32 is connected to an outlet of the electrical oil pump 12.

In particular, since the mechanical oil pump 11 and the electrical oil pump 12 are independently connected to the oil pan 15 through the first intake line 41 and the second intake line 42, respectively, they may independently operate more smoothly.

FIG. 3 is a view illustrating a transmission of a hybrid vehicle to which an oil pump system for a vehicle according to an exemplary form of the present disclosure is applicable.

The transmission for a hybrid vehicle illustrated in FIG. 3 has an input shaft 2 connected to an engine 1, a planetary gear set 3 installed in the input shaft 2, a first electric motor 4 selectively connected to the planetary gear set 3, a second electric motor 5 installed in a middle shaft 6 parallel to the input shaft 2, an overdrive brake 7 connected to the first electric motor 4, and a one-way clutch 8 connected to the planetary gear set 3.

As illustrated in FIG. 3, the mechanical oil pump 11 of an oil pump system for a vehicle is connected to the engine 1 through a gear or a pulley, and the electrical oil pump 12 may be disposed to be adjacent to the mechanical oil pump 11.

The oil pump system for a vehicle may be applied to a transmission of a hybrid vehicle illustrated in FIG. 3 to supply oil according to a supply flow rate of oil desired for the lubrication element 21, the control element 22, and the cooled element 23.

As a vehicle speed is increased, the lubrication element 21 has increased frictional contact or heat, and accordingly, an increased flow rate of oil for lubricating the lubrication element 21 is desired. Here, as illustrated in FIG. 4, the mechanical oil pump 11 may increase a supply flow rate of oil supplied to the lubrication element 21 in proportion to the vehicle speed through a structure connected to the engine 1 of the vehicle (please refer to A of FIG. 4).

The cooled element 23, such as the electric motor 4 or 5 as an auxiliary driving source, of the vehicle is rapidly increased in temperature under hill climbing conditions in which a vehicle speed is low and high torque is desired. Under this condition, the cooled element 23 is desired to be cooled, regardless of vehicle speed. When the cooled element 23 is desired to be cooled, an appropriate amount of oil may be supplied by the electrical oil pump 12 toward the cooled element 23 (please refer to B1 of FIG. 4).

Also, when the overdrive brake 7 is coupled to drive a vehicle at a high speed and thus to enhance fuel efficiency, the electrical oil pump 12 supplies an appropriate amount of oil toward the control element 22 (please refer to B2 and B3 of FIG. 4)

In a case where the electric motor 4 or 5 is desired to be cooled under condition that the overdrive brake 7 is coupled, that is, in a case where not only formation of control pressure for the control element 22 but also cooling of the cooled element 23 are simultaneously desired, the electrical oil pump 12 supplies an appropriate amount of oil toward the control element 22 and the cooled element 23 (please refer to B4 of FIG. 4).

As described above, since the electrical oil pump 12 and the mechanical oil pump 11 are operated independently each other, an oil flow or a flow rate of oil may be controlled according to conditions desired for each element so that fuel efficiency of the vehicle is enhanced. Also, since pumping capacity of each of the oil pumps 11 and 12 is reduced, a size, weight, and manufacturing cost may be reduced. In addition, due to the reduction in capacity of each of the oil pumps 11 and 12, a low voltage may be used through a reduction in maximum torque of the motor 16 of the electrical oil pump 12 under an extreme low temperature condition, thus increasing safety of a fail safe.

As described above, according to exemplary forms of the present disclosure, since the mechanical oil pump is configured to supply oil toward the lubrication element, the electrical oil pump is configured to supply oil toward the cooled element and the control element, and the mechanical oil pump and the electrical oil pump are independently driven, an oil flow or a flow rate of oil may be properly controlled according to characteristics of an oil flow rate desired for each element.

Hereinabove, although the present disclosure has been described with reference to exemplary forms and the accompanying drawings, the present disclosure is not limited thereto, but may be variously modified and altered by those skilled in the art to which the present disclosure pertains without departing from the spirit and scope of the present disclosure.

Claims

1. An oil pump system for a vehicle, the oil pump system comprising:

a mechanical oil pump configured to supply oil to a lubrication element; and

an electrical oil pump configured to supply oil to at least one of a cooled element or a control element,

wherein the mechanical oil pump and the electrical oil pump are independently operated.

2. The oil pump system according to claim 1, wherein a first oil flow channel configured to supply oil toward the lubrication element is connected to the mechanical oil pump.

3. The oil pump system according to claim 2, wherein the mechanical oil pump is connected to a driving source of a vehicle so as to be operated.

4. The oil pump system according to claim 1, wherein a second oil flow channel configured to supply oil toward the control element is connected to the electrical oil pump.

5. The oil pump system according to claim 4, wherein a third oil flow channel configured to supply oil toward the cooled element is connected to one side of the second oil flow channel.

6. The oil pump system according to claim 5, wherein a regulator valve configured to form control pressure of the control element is installed in a portion where the second oil flow channel and the third oil flow channel are connected.

7. An oil pump system for a vehicle, the oil pump system comprising:

an oil pan configured to store oil;

a mechanical oil pump configured to supply oil of the oil pan only to a lubrication element; and

an electrical oil pump configured to supply oil of the oil pan to at least one of a cooled element or a control element,

wherein the mechanical oil pump and the electrical oil pump are independently connected to the oil pan.

8. The oil pump system according to claim 7, wherein

a first intake line is connected to an inlet of the mechanical oil pump,

the first intake line is connected to one side of the oil pan, and

a first oil line configured to supply oil to the lubrication element is connected to an outlet of the mechanical oil pump.

9. The oil pump system according to claim 8, wherein

a second intake line is connected to an inlet of the electrical oil pump,

the second intake line is connected to the oil pan, and

a second oil line configured to supply oil to the control element is connected to an outlet of the electrical oil pump.

10. The oil pump system according to claim 9, wherein the first intake line and the second intake line are independently connected to the oil pan.

11. The oil pump system according to claim 9, wherein

a third oil flow channel configured to supply oil toward the cooled element is connected to one side of a second oil flow channel, and

a regulator valve is installed in a portion where the second oil flow channel and the third oil flow channel are connected.