Description:FIELD OF INVENTION

The present invention relates to farm machinery. In particular, the present invention relates to a hydraulic system for minimizing hydraulic power-loss in an agricultural vehicle. More particularly, the present invention relates to a method of controlling such an agricultural vehicle, such as a tractor.

BACKGROUND OF THE INVENTION

Agricultural vehicles are used in different applications using different implements attached thereto as attachments such as cultivator, rotavator, seed drill, lawn mower, thrasher, trolley, dozer, snow cutting machine, sprayer etc. for carrying out various agriculture-related operations. Some of these implements require hydraulic power for lifting/lowering or operating them and some of these implements do not require hydraulic power in any form for operations thereof.

At present, in the hydraulic systems for Hitch and external or auxiliary applications for most of the agricultural vehicles, a fixed displacement hydraulic pump (hereinafter referred to as a "hydraulic pump") is coupled to the vehicle engine, and this pump continuously runs with the vehicle engine.

This hydraulic pump sucks oil from the oil-reservoir in the transmission case through suction lines and filter and delivers the necessary oil-flow to the hydraulic systems through a respective hydraulic pressure line. The hydraulic pump provides oil-flow to operate the hydraulic system by consuming engine power as continuous power input received from the engine. The oil-flow provided by the hydraulic pump flows through pipe/s and hose/s and enters in the hydraulic control valves available in the agricultural vehicle/s.
When the hydraulic system is not operated, the oil-flow is not used for any work, and hydraulic control valve returns this oil-flow in the transmission case via an unloading valve which is a part of the hydraulic control valve.

This unloading valve poses a higher resistance to the continuous oil-flow based on the valve mechanism, orifice diameter and valve size, and this higher resistance results in the consumption of higher engine power, which forms a substantial hydraulic power-loss in the agricultural vehicle, like a tractor. This continuous power-loss leads to a reduction in the drawbar power and lowers the fuel efficiency of the agricultural vehicle.

In current practice, the hydraulic power is readily available for use in terms of a continuous hydraulic oil flow at the hydraulic control valve irrespective of the application and attached implement. Unloading valve of the hydraulic control valve dumps the oil-flow to the transmission case with higher resistance to oil-flow, causing a higher hydraulic power-loss even for the applications where the hydraulic power is not utilized.

To minimize the hydraulic power-loss in an agricultural vehicle, a system with a hydraulic bypass circuit is provided and the oil-flow is diverted to tank directly through “2/2 or 3/2 direction control valve” in the applications wherever the tractor hitch and external/auxiliary hydraulic system is not used. The driver is provided with an actuating mechanism like a switch/lever/linkage/electric switch to operate the “2/2 or 3/2 direction control valve” for setting this valve in different conditions. When the agricultural vehicle needs to use the hitch and external/auxiliary hydraulic system for operations depending on the position control, draft control and external/auxiliary functions, the driver has to close/shutoff this “2/2 or 3/2 direction control valve” by the aforesaid actuating mechanisms.
DESCRIPTION OF THE INVENTION

In accordance with the present invention, a hydraulic system for minimizing hydraulic power-loss in an agricultural vehicle, such as tractor is provided, which includes a hydraulic tandem pump assembly with a hydraulic pump for hitch and external/auxiliary control, and a hydraulic pump for power steering system; the pump assembly is mechanically coupled to an engine of the agricultural vehicle and receives power therefrom for hitch and external/auxiliary control as well as for steering system; a hydraulic filter connected before the pump assembly; a hydraulic filter to filter the impurities from hydraulic fluid-flow supplied to the pump assembly from the hydraulic fluid-tank or transmission housing of the agricultural vehicle; a relief valve connected between the pump assembly and a hitch control valve; a hydraulic power steering control system connected to the agricultural vehicle; the hitch control valve includes a main lifting valve, lowering control valve, and unloading valve each; the hitch control valve receives the hydraulic fluid from relief valve after passing through a removable manifold; the hitch control valve is connected to a hydraulic cylinder via a lubrication pipe; and the manifold connects an external hydraulic control valve for directly supplying the hydraulic fluid-flow for dozer/sprayer applications etc.; wherein a 2/2 or 3/2 direction control valve is connected to the relief valve, and when the hydraulic power from the hydraulic cylinder is required by the agricultural vehicle, a lower back pressure is exerted on the pump assembly during pumping the hydraulic fluid passing through the 2/2 or 3/2 direction control valve due to the fluid flow from the pump assembly to the 2/2 or 3/2 direction control valve.

The present invention also provided a method to control the agricultural vehicle by the above hydraulic system to reduce engine power consumption due to a lower resistance to the hydraulic fluid-flow because of a shorter fluid flow-path.
PRIOR ART

EP 2381115 B1 titled- “Hydraulic pump controller for construction machine” discloses a hydraulic pump controlling apparatus of a construction machine which includes: a hydraulic pump 10 in which a swash plate angle is controlled to control the discharge flow; an auxiliary pump 14; control valve 11 controlling the flow-direction of the fluid discharged from the hydraulic pump 10 and selectively supplying the fluid to actuator 13; orifice 15 and relief valve 16 connected between center bypass line 17 of the control valve 11 and tank T to be parallel to each other; signal pressure selecting units 20, 120, 220 receiving the fluid passing through center bypass line 17 and the fluid discharged from auxiliary pump 14, and selecting the pressure of any one of the fluids as the signal pressure; and regulator 30 receives the signal pressure selected from the signal pressure selecting units 20, 120, 220 to control the swash plate angle of hydraulic pump 10, and the signal pressure selecting unit 20 selects the pressure of the fluid discharged from auxiliary pump 14 as the signal pressure and transfers the selected pressure to the regulator 30 when the construction machine is in an idle state.

However, the above document concerns a construction machine including a variable displacement hydraulic pump. This innovation involves the change in flow or speed at the pump, i.e. by controlling the pump flow output based on the hydraulic system demand. So, it involves hydraulic pump controlling apparatus by an automated process with the help of this hydraulic control.

EP 2878830 A1 titled- “Hydraulic system for construction machine” discloses a hydraulic system provided with a relief valve for a construction machine, which can reduce a discharge flow rate of a hydraulic pump when a relief valve is operated. The hydraulic system for a construction machine includes a variable displacement hydraulic pump connected to an engine, an attachment operation device outputting an operation signal in proportion to an operation amount by an operator, an attachment actuator connected to the hydraulic pump to be driven by an operation of the attachment operation device, a control valve installed in a flow path between the hydraulic pump and the attachment actuator and shifted to control a start, a stop, and a direction change of the attachment actuator, an orifice installed in a flow path branched from a discharge flow path of the hydraulic pump, a relief valve installed on a downstream side of the orifice in the flow path, and a controller outputting a control signal to a flow control valve of the hydraulic pump so as to reduce a discharge flow rate of the hydraulic pump when a difference between pressures before and after the orifice exceeds a predetermined value.

However, the above document also concerns a construction machine including a variable displacement hydraulic pump. This innovation involves the change in flow or speed at the pump by controlling the pump flow output based on the pressure differential through an orifice. This involves a controller and sensor used in an automated process.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a hydraulic system for minimizing hydraulic power-loss in an agricultural vehicle, such as a tractor.

Another object of the present invention is to provide a method of controlling hydraulic power-loss in an agricultural vehicle using a hydraulic bypass circuit.
Still another object of the present invention is to provide a method of controlling hydraulic power-loss in a tractor for increasing the productivity of agricultural operations.

Yet another object of the present invention is to provide a method of controlling hydraulic power-loss in a tractor for increasing the fuel efficiency by minimizing power consumption.

A further object of the present invention is to provide a method of controlling hydraulic power-loss in a tractor for increasing the service-life of the hydraulic components such as pipes, pump, seals, etc.

An additional object of the present invention is to provide a method to minimize hydraulic power-loss in tractor by introducing hydraulic bypass circuit in applications not using tractor hitch and external/auxiliary hydraulic system.

A still further object of the present invention is to provide a method of controlling hydraulic power-loss in a tractor for reducing overall heat generation therein.

A yet further object of the present invention is to provide a method of controlling hydraulic power-loss in a tractor for obtaining environmental benefits by lowering the heat loss and carbon emission therein.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.

SUMMARY OF INVENTION

In accordance with the present invention, there is provided a hydraulic system for minimizing power-loss in an agricultural vehicle, the hydraulic system with a hydraulic circuit for the agricultural vehicle, the hydraulic circuit comprises:

- a hydraulic tandem pump assembly with a hydraulic pump for hitch and external/auxiliary control, and a hydraulic pump for power steering system;

- the pump assembly mechanically coupled to an engine of the agricultural vehicle and receiving power therefrom for hitch and external/auxiliary control;

- a hydraulic filter connected in a hydraulic line before the pump assembly;

- a hydraulic filter filtering out the impurities from the hydraulic fluid-flow supplied to the pump assembly from hydraulic fluid-tank or transmission housing of the agricultural vehicle;

- a relief valve connected between the pump assembly and a hitch control valve via a line receiving hydraulic fluid-flow therefrom;

- a hydraulic steering control system connected to the agricultural vehicle;

- the hitch control valve having a main lifting valve, a lowering control valve, and an unloading valve;

- the hitch control valve receiving the hydraulic fluid from the relief valve via a line after passing through a removable manifold;

- the hitch control valve is connected to a hydraulic cylinder via a lubrication pipe; and

- the manifold is configured to connect an external hydraulic control valve to directly supply hydraulic fluid-flow for dozer/sprayer applications and the like;
wherein a 2/2 direction control valve or 3/2 direction control valve is connected to the relief valve in the hydraulic circuit, and when the hydraulic power from the hydraulic cylinder is required, a lower back pressure is exerted on the pump assembly while pumping the hydraulic fluid passing through the direction control valve due to the fluid flow from the pump assembly to the direction control valve.

Typically, the external control valve with an external or auxiliary hydraulic circuit is connected via an auxiliary hydraulic line connected to the line receiving the hydraulic fluid-flow from the pump assembly via the relief valve, when the manifold is removed from the hydraulic system.

Typically, the 2/2 direction control valve or 3/2 direction control valve is a normally open (NO) direction control valve.

Typically, the 2/2 direction control valve or 3/2 direction control valve is a normally closed (NC) direction control valve.

Typically, the 2/2 direction control valve is open to the tank/reservoir to bypass the hitch control valve, when the hydraulic power from the hydraulic cylinder is required for operating hitch control valve.

Typically, the 3/2 direction control valve is open to the tank/reservoir to bypass the hitch control valve, when the hydraulic power from the hydraulic cylinder is required for operating the external/auxiliary control valve.

Typically, one port of the 3/2 direction control valve is closed by a plug.

Typically, the external control valve is configured to provide a shorter hydraulic fluid-flow path and to allow the hydraulic fluid to pass with lower neutral pressure due to the lower resistance offered by the direction control valve, and thus to reduce the engine power-loss when the hydraulic cylinder is not in use.

Typically, the hydraulic control valve is configured for splash lubrication of a hydraulic cylinder via a lubrication pipe, when the hydraulic functions of the agricultural machine are not required;

Typically, the hitch control valve is manually controlled to divert the hydraulic fluid-flow to the hydraulic cylinder through the main lifting valve and the hydraulic cylinder is extended in a forward stroke; and in a backward stroke, due to gravity, the piston of the hydraulic cylinder is moved backward to return/dump the hydraulic-fluid accumulated therein to the hydraulic fluid-tank or transmission housing through a port connected to the lowering control valve.

Typically, the hitch control valve is mechanically/electrically/electronically controlled to divert the hydraulic fluid-flow to the hydraulic cylinder through the main lifting valve.

In accordance with the present invention, there is also provided a method for minimizing the power-loss in an agricultural vehicle by the hydraulic system, wherein the 2/2 or 3/2 direction control valve connected in the hydraulic circuit is opened to the hydraulic fluid-tank or transmission housing by bypassing the hitch control valve for shortening the hydraulic fluid-flow path to pass with a lower back pressure. Thereby, it offers a lower resistance to the fluid flow to lower the back pressure experienced by the pump assembly for reducing the hydraulic power-loss and in turn engine power-loss, when the hydraulic power from the hydraulic cylinder is not required by the agricultural vehicle.
Typically, the 2/2 or 3/2 direction control valve is closed, when the hydraulic system is required for operating the hitch control valve or the external/auxiliary control valve for the respective application thereof.

Typically, the hydraulic control valve of the hydraulic system is manually operated for diverting the hydraulic fluid-flow to the hydraulic cylinder through the main lifting valve and extending the hydraulic cylinder in a forward stroke, and moving the piston of the hydraulic cylinder backward in a backward stroke thereof to return/dump the hydraulic fluid accumulated therein to the hydraulic fluid-tank or transmission housing.

Typically, the 2/2 or 3/2 direction control valve is closed, when the hydraulic system is operated mechanically/electrically/electronically.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described in the following with reference to the accompanying drawings.

Figure 1 shows a conventional hydraulic circuit for an agricultural vehicle, including a hydraulic filter connected in hydraulic line before pumps.

Figure 2 shows a hydraulic circuit for an agricultural vehicle configured in accordance with the present invention, comprising a hydraulic filter connected in hydraulic line before pumps and an additional 2/2 or 3/2 direction control valve.

Figure 3 shows a block diagram of conventional hydraulic system used for an agricultural vehicle.
Figure 4 shows a block diagram of hydraulic system configured in accordance with the present invention comprising a 2/2 or 3/2 direction control valve in the hydraulic circuit for an agricultural vehicle, when the hydraulic power is not in use.

Figure 5 shows a block diagram of hydraulic system configured in accordance with the present invention comprising a 2/2 or 3/2 direction control valve in the hydraulic circuit for an agricultural vehicle when the hydraulic power to be used.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, a system and method for controlling the power-loss in an agricultural vehicle like a tractor and configured in accordance with the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention.

Figure 1 shows a conventional hydraulic circuit HC1 for an agricultural vehicle. The hydraulic tandem pump assembly 2 consists of two hydraulic pumps named P1 and P2. The pump P1 is used for the hitch control and external/auxiliary control, and the pump P2 is used for the power steering system. The pump assembly 2 is mechanically coupled to the engine 6 of the agricultural vehicle (not shown), e.g. a tractor. A hydraulic power steering control system 4 is also connected to the agricultural vehicle. The pump assembly 2 used for hitch and external/auxiliary control receives the driving power from the engine 6 and also receives hydraulic fluid-flow from the hydraulic fluid-tank, i.e., transmission housing (not shown) for the agricultural vehicle via a hydraulic filter 1 connected in the hydraulic line L1 before the hydraulic pump 2. The hydraulic fluid-flow from the pump assembly 2 passes via line L2 through relief valve 3 and can also be connected via auxiliary hydraulic line AL to the external control valve 11 such as loader in the external or auxiliary hydraulic circuit EHC. This hydraulic fluid-flow L3 finally reaches the hitch control valve 5, and passes through a manifold 9 which is removable and provided to connect other external hydraulic control valve such as auxiliary valve (Hydraulic direction control valve with high pressure carry over) for applications such as dozer, sprayer etc. as well. If manifold 9 is available, the oil-flow proceeds further directly through the manifold 9. In case the manifold 9 is removed and the external hydraulic control valve is connected, the oil-flow returns back up-to the hitch control valve 5 similarly as through manifold 9. The oil-flow proceeds to the port P of the hitch control valve 5 and in neutral condition proceeds through unloading valve 5.3 of the hitch control valve 5 and lubrication pipe 10 and it is then dumped back to the hydraulic fluid-tank (not shown) as splash lubrication to the hydraulic cylinder 8, i.e. when the hydraulic functions of agricultural machine are not used. In this case, the hydraulic fluid passes through the complete hydraulic circuit HC1 and reaches up-to the hydraulic fluid-tank. Lubrication of the hydraulic cylinder 8 is not required when the hydraulic system is not used. Because of a longer path followed by the hydraulic fluid and due to the internal design resistance caused by the longer flow path and unloading valve 5.3 of the hitch control valve 5, the observed neutral pressure is substantially higher. When the hydraulic function is required to be used, the hitch control valve 5 is manually controlled and flow is diverted to the hydraulic cylinder 8 through hydraulic lifting valve and the hydraulic cylinder 8 is extended (forward stroke). In case of backward stroke, due to gravity, piston moves backward and accumulated oil from the cylinder returns to tank through T port connected to lowering control valve 5.2.

Figure 2 shows a hydraulic circuit HC2 for an agricultural vehicle configured in accordance with the present invention, which comprises a hydraulic filter 1 connected in hydraulic line L1 before pumps P1, P2 and an additional 2/2 direction control valve 7a or alternatively 3/2 direction control valve 7b. Since normally open or normally closed type of valve only affects the valve actuation, any of these 2 types of valve (7a, 7b) state is useful here.

Figure 3 shows a block diagram of the conventional (Figure 1) hydraulic system used for an agricultural vehicle by the conventional hydraulic circuit HC1 (Figure 1). It is shown in the block diagram (Figure 1) that the flow from the pump is reaching up-to cylinder through Hitch control valve 5 and returning to tank through the unloading valve 5.3 of the hitch control valve 5 and lubrication pipe 10, when the hydraulic cylinder is not in use. The different denotations are used to represent the flow of fluid, pressure and power in various conditions with arrows of different colors. The hydraulic pump powered by engine 6 pumps the hydraulic fluid up to the hitch control valve 5 with a higher pressure (as explained above with Figure 1) and thus causes higher power-loss, because of higher back-pressure to the pumping of fluid passing through the hydraulic hitch control valve 5 and/or external/auxiliary control valve AL.

Figure 4 shows a block diagram of hydraulic system configured in accordance with the present invention comprising a 2/2 or 3/2 direction control valve (7a or 7b) in the hydraulic circuit HC2 for an agricultural vehicle, when the hydraulic power is not in use. Here, hydraulic cylinder 8 is not in use, it means that the hydraulic power is not utilized; and because of the fluid flow from the pump assembly 2 to the 2/2 direction control valve (7a) or 3/2 direction control valve (7b), a lower back pressure is experienced by the pump assembly 2 during pumping of the fluid passing through the 2/2 or 3/2 direction control valve (7a or 7b). When the hydraulic system is not in use for operating hitch control valve 5 or external/auxiliary control valve AL for their respective applications, the 2/2 direction control valve (7a) or 3/2 direction control valve (7b) is open to the tank/reservoir and bypasses the hydraulic control valve HC (5). The shorter path of the hydraulic fluid and the lower resistance offered by this 2/2 direction control valve (7a) or 3/2 direction control valve (7b) allows the fluid to pass with lower neutral pressure. Therefore, this lower neutral pressure reduces the engine power-loss when the hydraulic cylinder 8 is not in use. However, a hitch control valve (5) having a different configuration from this configuration may also be used.

Figure 5 shows a block diagram of hydraulic system configured in accordance with the present invention comprising a 2/2 or 3/2 direction control valve (7a or 7b) in the hydraulic circuit for an agricultural vehicle, when the hydraulic power is to be used. When the hydraulic system is to be used for operating hitch control valve 5 or external/auxiliary control valve AL for their respective applications. This 2/2 or 3/2 direction control valve (7a or 7b) remains closed and hydraulic functions works as usual as explained in the description of Figure 1, when the hydraulic function is required and the hydraulic power is utilized against the work.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The hydraulic system and method configured in accordance with the present invention, for minimizing power-loss in an agricultural vehicle, such as a tractor offers the following advantages:

• Minimizes the hydraulic power-loss in agricultural vehicle, e.g. tractor.

• Increases the fuel efficiency by minimizing power consumption.

• Increases the productivity of agricultural and other activities.

• Flexibility of using 2/2 or 3/2 direction control valve mechanically or electrically or electronically.

• Increases the service-life of hydraulic components like pipes, pumps, seals, etc.

• Reduces the overall heat generation in the agricultural vehicle.

• Provides environmental benefits by lower heat-loss/carbon emission.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

It is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners to use this embodiment and to further enable the skilled person in the relevant art to practice this invention.

Although, the embodiments presented in this disclosure have been described in terms of its preferred embodiments, the skilled person in the art would readily recognize that these embodiments can be applied with modifications possible within the spirit and scope of the present invention as described in this specification by making innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in different size, shape, orientation and interrelationship without departing from the scope and spirit of this invention.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to imply including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps. The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.

The description of the exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which are to be considered part of the entire written description. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top”, and “bottom” as well as derivatives thereof (e.g. “horizontally”, “inwardly”, “outwardly”; “downwardly”, “upwardly” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion.

These relative terms are for convenience of description and do not require that the corresponding apparatus or device be constructed or operated in a particular orientation.
Terms concerning attachments, coupling and the like, such as “connected” and “interconnected”, refer to a relationship, wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. , Claims:We claim:

1. A hydraulic system for minimizing power-loss in an agricultural vehicle, said hydraulic system with a hydraulic circuit (HC2) for said agricultural vehicle, said hydraulic circuit (HC2) comprising:

(i) a hydraulic tandem pump assembly (2) with a hydraulic pump (P1) for hitch and external/auxiliary control, and a hydraulic pump (P2) for power steering system;

(ii) said pump assembly (2) mechanically coupled to an engine (6) of said agricultural vehicle and receiving power therefrom for hitch and external/auxiliary control;

(iii) a hydraulic filter (1) connected in a hydraulic line (L1) before said pump assembly (2);

(iv) said hydraulic filter (1) filtering out the impurities from the hydraulic fluid-flow supplied to said pump assembly (2) from hydraulic fluid-tank or transmission housing of said agricultural vehicle;

(v) a relief valve (3) connected between said pump assembly (2) and a hitch control valve (5) via a line (L2) receiving hydraulic fluid-flow therefrom;

(vi) a hydraulic steering control system (4) connected to said agricultural vehicle;

(vii) said hitch control valve (5) having a main lifting valve (5.1), a lowering control valve (5.2), and an unloading valve (5.3);

(viii) said hitch control valve (5) receiving the hydraulic fluid from said relief valve (3) via a line (L3) after passing through a removable manifold (9);
(ix) said hitch control valve (5) connected to a hydraulic cylinder (8) via a lubrication pipe (10); and

(x) said manifold (9) configured to connect an external hydraulic control valve (11) to directly supply hydraulic fluid-flow for dozer/sprayer applications and the like;

wherein a 2/2 direction control valve or 3/2 direction control valve (7a; 7b) is connected to said relief valve (3) in said hydraulic circuit (HC2), and when the hydraulic power from said hydraulic cylinder (8) is required, a lower back pressure is exerted on said pump assembly (2) while pumping the hydraulic fluid passing through said direction control valve (7a; 7b) due to the fluid flow from said pump assembly (2) to said direction control valve (7a; 7b).

2. The hydraulic system as claimed in claim 1, wherein an external control valve (11) with an external or auxiliary hydraulic circuit (EHC) is connected via an auxiliary hydraulic line (AL) connected to said line (L2) receiving the hydraulic fluid-flow from said pump assembly (2) via said relief valve (3), when said manifold is removed from said hydraulic system.

3. The hydraulic system as claimed in claim 1, wherein said 2/2 direction control valve (7a) or said 3/2 direction control valve (7b) is a normally open (NO) direction control valve.

4. The hydraulic system as claimed in claim 1, wherein said 2/2 direction control valve (7a) or said 3/2 direction control valve (7b) is a normally closed (NC) direction control valve.

5. The hydraulic system as claimed in claim 3, wherein said 2/2 direction control valve (7a) is open to the tank/reservoir to bypass said hitch control valve (5), when the hydraulic power from said hydraulic cylinder (8) is required for operating hitch control valve (5).

6. The hydraulic system as claimed in claim 5, wherein said direction control valve (7b) is open to the tank/reservoir to bypass said hitch control valve (5), when the hydraulic power from said hydraulic cylinder (8) is required for operating said external/auxiliary control valve (AL).

7. The hydraulic system as claimed in claim 3 or 4, wherein one port of said 3/2 direction control valve (7b) is closed with a plug.

8. The hydraulic system as claimed in claim 2, wherein said external control valve (11) is configured to provide a shorter hydraulic fluid-flow path and to allow the hydraulic fluid to pass with lower neutral pressure due to the lower resistance offered by said direction control valve (7a; 7b), and thus to reduce the engine power-loss when the hydraulic cylinder (8) is not in use.

9. The hydraulic system as claimed in claim 1, wherein said hydraulic control valve (5) is configured for splash lubrication of a hydraulic cylinder (8) via a lubrication pipe (10), when the hydraulic functions of said agricultural machine are not required.

10. The hydraulic system as claimed in claim 9, wherein said hitch control valve (5) is manually controlled to divert the hydraulic fluid-flow to said hydraulic cylinder (8) through said main lifting valve (5.1) and said hydraulic cylinder (8) is extended in a forward stroke; and in a backward stroke, due to gravity the piston of said hydraulic cylinder (8) is moved backward to return/dump the hydraulic-fluid accumulated therein to the hydraulic fluid-tank or transmission housing through a port (T) connected to said lowering control valve (5.2).
11. The hydraulic system as claimed in claim 1, wherein said hitch control valve (5) is mechanically/electrically/electronically controlled to divert the hydraulic fluid-flow to said hydraulic cylinder (8) through said main lifting valve (5.1).

12. A method for minimizing the power-loss in an agricultural vehicle by the hydraulic system as claimed in anyone of the preceding claims 1-11, wherein said 2/2 or 3/2 direction control valve (7a or 7b) connected in said hydraulic circuit (HC2) is opened to the hydraulic fluid-tank or transmission housing by bypassing said hitch control valve (5) for shortening the hydraulic fluid-flow path to pass with a lower back pressure and thereby offering a lower resistance to the fluid-flow to lower the back pressure experienced by said pump assembly (2) for reducing the hydraulic power-loss and in turn, the engine power-loss, when the hydraulic power from said hydraulic cylinder (8) is not required by said agricultural vehicle.

13. The method as claimed in claim 12, wherein said 2/2 or 3/2 direction control valve (7a; 7b) is closed, when said hydraulic system is required for operating said hitch control valve (5) or said external/auxiliary control valve (AL) for the respective application thereof.

14. The method as claimed in claim 13, wherein said hydraulic control valve (5) of said hydraulic system is manually operated for diverting the hydraulic fluid-flow to said hydraulic cylinder (8) through said main lifting valve (5.1) and extending said hydraulic cylinder (8) in a forward stroke, and moving the piston of said hydraulic cylinder (8) backward in a backward stroke thereof to return/dump the hydraulic fluid accumulated therein to the hydraulic fluid-tank or transmission housing.

15. The method as claimed in claim 12, wherein said 2/2 or 3/2 direction control valve (7a; 7b) is closed, when said hydraulic system is operated mechanically/electrically/electronically.

Dated this 08th day of February 2024.

Digitally / e-Signed by:

(SANJAY KESHARWANI)
APPLICANT’S PATENT AGENT
REGN. NO. IN/PA-2043.