DESC:FIELD OF INVENTION

The present invention relates to a tractor engine with convertible speed. In particular, the present invention relates to a tractor engine for operating implements requiring constant PTO speeds. More particularly, the present invention relates to a tractor engine which can operate both as a variable speed and constant speed engine.

BACKGROUND OF THE INVENTION

In the modern tractors, the engine is governed by means of a variable speed governor. So, for a given constant throttle position, the speed varies depending on the load from the implement attached to the tractor. With an increase in load, the speed reduces, and vice versa. Some of the tractor implements powered by the power take-off (PTO) unit, e.g. Rotavator, Thresher, Sprayer etc. require a constant PTO speed for the achieving an optimum functioning. However, due to the variable speed of the engine under variable load conditions, the engine speed also varies. This causes poor quality output.

Moreover, in the current rural scenario, most villages have an acute shortage of electricity. Most rural farmers cannot afford to use generator sets or other means of power generation. However, many villages have tractors being used for farming. Therefore, it is necessary that whole range of agricultural implements, like Rotavator, Thresher, Sprayer etc. requiring a constant PTO speed can be operated by the tractor engine itself, whenever there is no electricity available.

PRIOR ART

US 4307690 A discloses an electronic, variable speed engine governor for an engine. The governor utilizes the approximate digital equivalent of a lead and a lag feedback network in combination with a stored, digital, nonlinear look-up table, or other nonlinear means, to control engine speed. The governor controls the engine at different fixed engine speeds in response to demand, or at continuously variable engine speeds in response to demand. Similar engine governors for generator sets are also manufactured and marketed by Sedemac.
DISADVANTAGES WITH THE PRIOR ART

The following are the disadvantages with the tractor engine currently available in the market are discussed above:

Currently, no tractor engine is available which can also operate the implements working on constant PTO speeds, e.g. Rotavator, Thresher, Sprayer etc. This is particularly troublesome for the farmers in the regions having no electricity or where power supply is frequently interrupted, e.g. in non-electrified or rural area poorly supplied with electricity in a vast country like India.

Therefore, there is a need to develop a tractor engine, which can operate both at variable and constant speeds, so that the same tractor engine can be used for farming activities as well as for other auxiliary activities like threshing, spraying etc. by using implements that require a constant PTO output.

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 tractor engine which can be easily converted from a variable speed operation to a constant speed operation and vice-versa.

Another object of the present invention is to provide a tractor engine, in which speed switching options are provided for easily converting the operational mode.

Still another object of the present invention is to provide a tractor engine, which facilitates operating constant PTO speed implements in absence of electric supply.

Yet another object of the present invention is to provide a tractor engine, which achieves optimum performance from the tractor in a wide range of farming activities.
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 THE INVENTION

In accordance with the present invention, there is provided a tractor engine operating on variable speed and constant speed, wherein the tractor comprises: a foot-operated accelerator and a hand-operated accelerator for selectively actuating a speed governor, a fuel injection pump connected to the speed governor as well as tractor engine, which in turn is coupled to an application load, characterized in that a mode selection switch is connected to the fuel injection pump as well as the tractor engine via an electronic module for selectively operating the tractor engine on a constant speed mode CSM or a variable speed mode VSM based on the application load connected to the tractor engine.

Typically, the constant speed mode CSM is selected for a standstill condition of the tractor for operating an agricultural implement at constant PTO speed, such as Rotavator, sprayer or the like.

Typically, the variable speed mode VSM is selected for performing normal farming operations by the tractor.

Typically, the speed governor is configured as a mechanical speed governor.

Typically, the speed governor is configured as an electronic speed governor.

Typically, the fuel injection system is configured as a mechanical fuel injection system.

Typically, the fuel injection system is configured with an electronic module comprising:

- a speed sensor to sense flywheel speed;

- an actuator to control the stop lever for controlling connecting rod position to control the speed constant; and

- electronic control unit to control actuator movement as a function of the sensed engine speed;

wherein the modes and operational sequence of the electronic module is configured in the engine management system (EMS) for attachment to the existing fuel injection pump.

Typically, the fuel injection system is configured as an electronic fuel injection system.

Typically, the engine management system (EMS) of the engine is configured with modes of operation (CSM, VSM) for common rail fuel injection system.

Typically, the speed governor is configured as a combination of mechanical and electronic speed governing mechanism.

DESCRIPTION OF THE INVENTION

The idea underlying the present invention is to configure an engine which can be operated both as a variable speed engine and a constant speed engine. Here, the new engine can switch from a variable speed mode (VSM) to a constant speed mode (CSM) depending on the input from the tractor operator.

The engine speed governing system configured in accordance with the present invention can be applied to any type of engine governing system. The engine speed governing mechanism can be a mechanical or electronic system or a combination of both, depending on the type of fuel injection system (mechanical or electronic) used therein. However, the basic characteristic operational features of this engine governing system are enumerated below:

1. Operator choosing the no-load speed using the hand accelerator.

2. Subsequently, the operator chooses the CSM, while the tractor is in a standstill condition.
This system can be used for both mechanical fuel injection system and electronic fuel injection system.

In case of mechanical fuel injection system, there will be an additional module to the existing fuel injection pump. This module consists of:

1. A speed sensor to sense the flywheel speed.

2. An Electronic Control Unit (ECU) for controlling the actuators depending on the engine speed.

3. An actuator to control the stop lever, and thereby a control rod position to control the speed constant.

In case of the common rail / electronic fuel injection system, the modes and the working logic thereof are built into the engine management system (EMS).

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, wherein:

Figure 1a shows a schematic arrangement of a conventional tractor engine.

Figure 1b shows the normal torque curve on operating the engine shown in Figure 1a in a variable speed mode (VSM).

Figure 2a shows a schematic arrangement of a tractor engine configured in accordance with the present invention, which can be operated both as a variable speed engine and as a constant speed engine.

Figure 2b shows the normal torque curve on operating the engine shown in Figure 2a in a variable speed mode (VSM).

Figure 2c shows the normal torque curve on operating the engine shown in Figure 2a in a constant speed mode (CSM).

Figure 3a shows a schematic arrangement of the tractor engine of Figure 2, which is selected to be operated in a variable speed mode (VSM) based on the operator’s input.

Figure 3b shows a normal torque curve on operating the engine of Figure 2a in a variable speed mode (VSM).

Figure 4a shows a schematic arrangement of the tractor engine of in Figure 2, which is selected to be operated in a Constant Speed mode (CSM).

Figure 4a shows a schematic arrangement of the tractor engine of in Figure 2, selected for operation in CSM by using a mode selection switch.

Figure 4b shows the normal torque curve on operating the engine shown in Figure 4a in CSM.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, the tractor engine 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 in any way.

Figure 1a shows a schematic arrangement of a conventional tractor engine. Here, the tractor operator 10 is provided with a foot-operated accelerator 12, a hand-operated accelerator 14, which actuate the speed governor 16. The speed governor 16 is also connected to a fuel injection pump (FIP) 18 and engine 20, which in turn is coupled to an application load 22, such as a Rotavator, Thresher, Sprayer etc.

Figure 1b shows the normal torque curve on operating the engine shown in Figure 1a in variable speed mode (VSM). Here, the engine speed (rpm) on x-axis is plotted against the torque or load (N-m) on y-axis.

Figure 2a shows a schematic arrangement of a device configured in accordance with the present invention for operating the tractor engine either as a normal/variable speed engine or a constant speed engine. Accordingly, depending on the input from the operator 100, this engine can be switched from a variable speed mode (VSM) to a constant speed mode (CSM). Here, the tractor operator 100 is provided with a foot-operated accelerator 112, a hand-operated accelerator 114, which actuate the speed governor 116. The speed governor 116 is also connected to a fuel injection pump (FIP) 118 as well as engine 120, which in turn is coupled to an application load 122. The tractor operator 100 has access to a mode selection switch 102, which is connected to a CS Module 104, which in turn is also connected to FIP 118 and engine 120.

Figure 2b shows the normal torque curve on operating the engine shown in Figure 2a in a variable speed mode (VSM). Here, engine speed (rpm) on x-axis is plotted against the torque or load (N-m) on y-axis.

Figure 2c shows the normal torque curve on operating the engine shown in Figure 2a in a constant speed mode (CSM). As in Figure 2b, the engine speed (rpm) on x-axis is plotted against the torque or load (N-m) on y-axis.

Figure 3a shows a schematic arrangement of the tractor engine of Figure 2a, which is selected to be operated in a variable speed mode (VSM) 208 based on the input from the operator. Here, the tractor operator 200 is provided with a foot-operated accelerator 212, a hand-operated accelerator 214, which actuates the speed governor 216. The speed governor 216 is also connected to a FIP) 218 and engine 220, which is coupled to an application load 222. The mode selection switch 208 is similarly connected to a CS Module 210, which in turn is connected to FIP 218 and engine 220. Here, inactive signal flow-path is shown by dashed lines and the remaining signal flow-path is active and depicted by continuous lines.

Figure 3b shows the normal torque curve on operating the engine 220 shown in Figure 3a in a variable speed mode (VSM). Here, engine speed (rpm) on x-axis is plotted against the torque or load (N-m) on y-axis.

Figure 4a shows a schematic arrangement of the tractor engine of in Figure 2a, which is now selected to be operated in a Constant Speed mode (CSM) by using the mode selection switch 206. The tractor engine can be activated in this mode only when it is in a standstill (No load) condition. The operator can set a no-load speed, using the hand accelerator 214. Once this no-load speed is selected, the operator indicates to the system to switch to CSM. This can be done by using a push button or switch. Once the engine switches to the constant speed mode, the engine remains operating only at constant speed until further selection to change the operational mode thereof. Here also, the inactive signal flow-path is shown by dashed lines, while the remaining signal flow-path is active and depicted by continuous lines. The rest of the arrangement is same as in Figure 3a.

Figure 4b shows the normal torque curve on operating the engine 220 shown in Figure 4a in a constant speed mode (CSM). Here, engine speed (rpm) on x-axis is plotted against the torque or load (N-m) on y-axis.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The convertible tractor engine for operating agricultural implements operating on constant PTO speeds configured in accordance with the present invention has the following technical and economic advantages:

• Can be easily converted from variable speed operation to constant speed operation by a using mode switch.

• Enable the tractor operator to switch operational mode from his seat.
• Facilitates operation of implements requiring constant PTO speed in the absence of electricity.

• Can be used for both variable speed and constant speed operations.

The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention. The description provided herein is purely by way of example and illustration.

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 terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of this invention.

While considerable emphasis has been placed on the specific features of the preferred embodiment described here, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiments without departing from the principles of the invention.

These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby 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.

Many of the fastening, connection, processes and other means and components utilized in this invention are widely known and used in the field of the invention described, and their exact nature or type is not necessary for an understanding and use of the invention by a person skilled in the art and they will not therefore be discussed in significant detail.

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 implies 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.

Also, any reference herein to the terms ‘left’ or ‘right, ‘up’ or ‘down, or ‘top’ or ‘bottom’ are used as a matter of mere convenience, and are determined by standing at the rear of the machine facing in its normal direction of travel.

Furthermore, the various components shown or described herein for any specific application of this invention can be widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail. When referring to the figures, like parts are numbered the same in all of the figures. ,CLAIMS:We claim:

1. A tractor engine operating on variable speed and constant speed, wherein the tractor comprises: a foot-operated accelerator (112, 212) and a hand-operated accelerator (114, 214) for selectively actuating a speed governor (116, 216), a fuel injection pump (118, 218) connected to the speed governor (116, 216) as well as tractor engine (120, 220), which in turn is coupled to an application load (122, 222), characterized in that a mode selection switch (102, 202) is connected to the fuel injection pump (118, 218) as well as the tractor engine (120, 220) via an electronic module (104, 204) for selectively operating the tractor engine (120, 220) on a constant speed mode CSM (106, 206) or a variable speed mode VSM (108, 208) based on the application load (122, 222) connected to the tractor engine (120, 220).

2. Engine as claimed in claim 1, wherein the constant speed mode CSM (106, 206) is selected for a standstill condition of the tractor for operating an agricultural implement at constant PTO speed, such as Rotavator, sprayer or the like.

3. Engine as claimed in claim 1, wherein the variable speed mode VSM (108, 208) is selected for performing normal farming operations by the tractor.

4. Engine as claimed in claim 1, wherein the speed governor (116, 216) is configured as a mechanical speed governor.

5. Engine as claimed in claim 1, wherein the speed governor (116, 216) is configured as an electronic speed governor.

6. Engine as claimed in claim 1, wherein the fuel injection system (118, 218) is configured as a mechanical fuel injection system.

7. Engine as claimed in claim 6, wherein the fuel injection system (118, 218) is configured with an electronic module comprising:

- a speed sensor to sense flywheel speed;
- an actuator to control the stop lever for controlling connecting rod position to control the speed constant; and

- electronic control unit to control actuator movement as a function of the sensed engine speed;

wherein the modes and operational sequence of the electronic module is configured in the engine management system (EMS) for attachment to the existing fuel injection pump.

8. Engine as claimed in claim 1, wherein the fuel injection system (118, 218) is configured as an electronic fuel injection system.

9. Engine as claimed in claim 8, wherein the engine management system (EMS) of the engine is configured with modes of operation (CSM, VSM) for common rail fuel injection system.

10. Engine as claimed in claim 1, wherein the speed governor (116, 216) is configured as a combination of mechanical and electronic speed governing mechanism.

Dated: this 28th day of October 2016. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT