EP4347345A1

EP4347345A1 - System and method for controlling engine operations

Info

Publication number: EP4347345A1
Application number: EP22816644.3A
Authority: EP
Inventors: Saravanan Sankaran; James A. Davies
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2021-06-03
Filing date: 2022-05-19
Publication date: 2024-04-10
Also published as: WO2022256178A1; BR112023025011A2

Abstract

System (200) and method (600) for controlling operations of an engine (114) is provided. The method (600) includes operating (602), by electronic controller (202), engine (114) in one of first operating mode or second operating mode. First operating mode is an isochronous operating mode facilitating adjusting engine speed to match target engine speed corresponding to change in engine load from no-load to full load. Second operating mode is droop operating mode facilitating predefined decrease in engine speed corresponding to change in engine load from no-load to full load. Electronic controller (202) receives (604), via engine mode switch (214), operator input indicating change in operating mode of engine (114) and determines (606) current operating mode of engine (114). Electronic controller (202) controls engine (114) to change operating mode based on received operator input and determined current operating mode of engine (114) and controls engine speed in accordance with changed operating mode corresponding to change in engine load.

Description

SYSTEM AND METHOD FOR CONTROLLING ENGINE OPERATIONS

Technical Field

The present disclosure generally relates to an engine control of a machine. More particularly, the present disclosure relates to a method and system for controlling engine operations to achieve fuel efficiency.

Background

Fuel efficiency of a machine has always been one of the most important parameters in evaluating performance and market value of the machine. Over the years, numerous systems and methods have been devised to improve fuel efficiencies of the machines and the topic still remains as one of most evolving area of research and development. Generally, electronic engines are considered to be more fuel efficient as compared to mechanical engines. Thus, mechanical engines have been replaced with electronic engines in many machines.

In electronic engines, to further increase the fuel efficiency, one of the common approaches is to have a separate electronic hydraulic pump displacement to cater to the fuel consumption and productivity requirements of the machine. However, having a separate electronic hydraulic pump displacement is expensive and structurally complex to implement, which makes it undesirable. Moreover, many machines do not even have electronics associated with the hydraulic system of the machine and thus, implementing a separate electronic hydraulic pump displacement may not even be possible.

US Patent Publication No. 2014/0200795 (hereinafter referred to as the ’795 publication) provides an engine control device that includes a detection unit, a no-load maximum speed computation unit, a target matching speed computation unit, and a target engine output computation unit. The detection unit is for detecting the operating state of a working machine. The no-load maximum speed computation unit is for computing a no-load maximum speed being an engine speed to be increased to the maximum upon a load of the working machine being released, based on the operating state. Further, the target matching speed computation unit for computing a target matching speed being an engine speed to be increased upon a load being applied to the working machine, separately from the no-load maximum speed, based on the operating state. The target engine output computation unit is for computing target engine output EL that can be outputted to the maximum, based on the operating state. The engine control device also includes an engine control unit for controlling the engine speed between the no-load maximum speed and the target matching speed under a restriction of the target engine output.

Summary of the Invention

In one aspect, a method for controlling operations of an engine is provided. The method includes operating, by electronic controller, engine in one of first operating mode or second operating mode. First operating mode is an isochronous operating mode facilitating adjusting engine speed to match target engine speed corresponding to change in engine load from no-load to full load. Second operating mode is droop operating mode facilitating predefined decrease in engine speed corresponding to change in engine load from no-load to full load. Electronic controller receives, via engine mode switch, operator input indicating change in operating mode of engine and determines current operating mode of engine. Electronic controller controls engine to change operating mode based on received operator input and determined current operating mode of engine and adjusts engine speed in accordance with changed operating mode corresponding to change in engine load.

In another aspect of the present disclosure, a power system for controlling operations of an engine of a machine is provided. The power system includes an engine mode switch and an electronic controller. The engine mode switch is configured to selectively activate one of a first operating mode or a second operating mode of the engine. The first operating mode is an isochronous operating mode facilitating adjusting an engine speed to match a target engine speed corresponding to a change in engine load from no-load to full load and the second operating mode being a droop operating mode facilitating a predefined decrease in the engine speed corresponding to the change in engine load from no-load to full load. The electronic controller is operatively coupled to the engine mode switch and the engine. The electronic controller is configured to operate the engine in one of the first operating mode or the second operating mode based on an activated operating mode. The electronic controller is further configured to receive an operator input via the engine mode switch, the operator input indicating a change in the operating mode of the engine. The electronic controller is configured to determine a current operating mode of the engine and control the engine to change the operating mode from one of the first operating mode and the second operating mode to the other of the first operating mode and the second operating mode based on the received operator input and the determined current operating mode of the engine. The electronic controller is further configured to adjust the engine speed in accordance with the changed operating mode of the engine corresponding to the change in engine load.

In a yet another aspect of the present disclosure, a machine is provided. The machine includes a machine frame configured to support an operator cabin and ground engaging members, the operator cabin including an operator console having one or more controls for operating the machine. A machine implement is coupled to the machine frame and configured to perform one or more implement operations. An engine is configured to power the machine and a power system is for controlling operations of the engine. The power system includes an engine mode switch and an electronic controller. The engine mode switch is positioned inside the operator cabin and configured to selectively activate one of a first operating mode or a second operating mode of the engine. The first operating mode is an isochronous operating mode facilitating adjusting an engine speed to match a target engine speed corresponding to a change in engine load from no-load to full load. The second operating mode being a droop operating mode facilitating a predefined decrease in the engine speed corresponding to the change in engine load from no-load to full load. The electronic controller is operatively coupled to the engine mode switch and the engine. The electronic controller is configured to operate the engine in one of the first operating mode or the second operating mode based on an activated operating mode. The electronic controller receives an operator input via the engine mode switch, the operator input indicating a change in the operating mode of the engine. The electronic controller determines a current operating mode of the engine and controls the engine to change the operating mode from one of the first operating mode and the second operating mode to the other of the first operating mode and the second operating mode based on the received operator input and the determined current operating mode of the engine. The electronic controller adjusts the engine speed in accordance with the changed operating mode of the engine corresponding to the change in engine load.

Brief Description of the Drawings

FIG. 1 illustrates an exemplary machine operating at a worksite, according to the embodiments of the present disclosure;

FIG. 2 illustrates an exemplary power system of the machine, in accordance with the embodiments of the present disclosure;

FIG. 3 illustrates an exemplary electronic controller within the power system for controlling operations of an engine of the machine, in accordance with the embodiments of the present disclosure;

FIG. 4 illustrates an exemplary engine map for operating the engine in a first operating mode, in accordance with the embodiments of the present disclosure;

FIG. 5 illustrates an exemplary engine map for operating the engine in a second operating mode, in accordance with the embodiments of the present disclosure;

FIG. 6 illustrates an exemplary method for controlling operations of the engine, in accordance with the embodiments of the present disclosure;

FIG. 7 illustrates an exemplary graph of engine operation in the first operating mode, in accordance with the embodiments of the present disclosure; and FIG. 8 illustrates an exemplary graph of engine operation in the second operating mode, in accordance with the embodiments of the present disclosure.

Detailed Description

The present disclosure relates to a system and method for controlling operations of an engine of a machine. To this end, FIG. 1 illustrates an exemplary machine 100 configured to operate at a worksite 102. The worksite 102 may include a mine site, a landfill, a quarry, a construction site, or any other type of worksite. In an example, the machine 100 is embodied as a backhoe loader. In other embodiments, the machine 100 may be any other machine such as a wheel loader, a motor grader, a truck, a tractor, a dozer, an excavator, a generator, and so on. The machine 100 may be configured to perform activities such as excavation, demolishment, transportation, material handling, and so on at the worksite 102. In other embodiments, the machine 100 may be any machine related to an industry including, but not limited to, transportation, construction, manufacturing, power generation, material handling, marine, aviation, and aerospace.

As shown in FIG. 1, the machine 100 includes a frame 104 that supports various components of the machine 100, such as a set of ground engaging members 106 and an operator cabin 108. In an exemplary embodiment, the ground engaging members 106, as shown in FIG. 1, include a pair of front wheels 110 and a pair of rear wheels 112 (only one side shown). However, in other exemplary embodiments, the ground engaging members 106 may alternatively include endless tracks for maneuvering the machine 100 at the worksite 102. The movement of the ground engaging members 106 may be powered by a power source, such as an engine 114 via a transmission (not shown). The engine 114 may be based on one of the commonly applied power generation units, such as an internal combustion engine (ICE) having a V-type configuration, inline configuration, or an engine with different configurations, as are conventionally known. However, aspects of the present disclosure need not be limited to a particular type of power source. The frame 104 defines a front end 118 and a rear end 120 of the machine 100. The terms ‘front’ and ‘rear’, as used herein, are in relation to a direction of travel of the machine 100, as represented by arrow, T, in FIG. 1, with said direction of travel being exemplarily defined from the rear end 120 towards the front end 118. The front end 118 is supported on the pair of front wheels 110 and is configured to support a first implement, such as a front loader 122. Similarly, the rear end 120 is supported on the pair of rear wheels 112 and is configured to support a second implement, such as a backhoe 124. The front loader 122 and the backhoe 124 may each be configured to perform one or more implement operations at the worksite 102.

The front loader 122 includes a pair of loader arms 126 having a coupler 128 for coupling a loader bucket 130 thereto. The front loader 122 and the loader bucket 130 may be raised or lowered with respect to the front end 118 of the frame 104 via a first set of hydraulic actuators 132. The backhoe 124 includes a boom 134, an arm 136 and a backhoe bucket 138. The boom 134 may be movably attached to a swing assembly 140 movably attached to the rear end 120 of the frame 104. The backhoe 124 and the backhoe bucket 138 may be raised or lowered with respect to the rear end 120 of the frame 104 via a second set of hydraulic actuators including actuators 142, 144, and 146. The machine 100 may further include a hydraulic system 148 to power the hydraulic actuators 132, 142, 144, 146. The hydraulic system 148 may include a hydraulic pump (not shown) that provides a flow of pressurized fluid to cause motion of each of the hydraulic actuators 132, 142, 144, 146.

The operator cabin 108 may include an operator seat 150 and an operator console 152 positioned therein. The operator console 152 may include various input-output controls for operating the machine 100, the front loader 122, the backhoe 124 and various other components of the machine 100. For example, the operator console 152 may include, but not limited to, one or more of steering wheel, touch screens, display devices, joysticks, switches etc., to facilitate an operator in operating the machine 100 and its components. Although the operator cabin 108 and the operator console 152 is shown to be on-board the machine 100, it may be contemplated that in some examples, the operator console 152 and/or the operator cabin 108 itself may also be positioned remotely with respect to the machine 100 and/or the worksite 102.

Referring to FIG. 2, an exemplary power system 200 of a machine, such as the machine 100 is illustrated. As shown, the power system 200 includes a prime mover, such as the engine 114, in the illustrated example. The engine 114 is configured to provide power to various components of the machine 100 during operations. In an exemplary embodiment of the present disclosure, the power system 200 includes an electronic controller 202, such as an engine control unit, configured to control the operations of the engine 114. The electronic controller 202 may be a single controller or may include more than one controllers disposed to control various functions and/or features of the engine 114. In this embodiment, the term “controller” is meant to include one, two, or more controllers that may be associated and that may cooperate in controlling various functions and operations of the engine 114.

In the illustrated embodiment, the power system 200 includes various links disposed to exchange information and command signals between the electronic controller 202 and the various components of the machine 100. Such links may be of any appropriate type and may be capable of two-way exchange of multiple signals. In one embodiment, such links may be channels of communication between various devices that are connected to one another via a confined area network (CAN).

The power system 200 may further include a machine propel system 204 including one or more components that cooperate to move the machine 100. As shown, the engine 114 is configured to provide power to the machine propel system 204. The machine propel system 204 may include electric, hydraulic, mechanical, pneumatic, or any other types of motive power generation for the machine 100. Accordingly, the engine 114 may provide power to the machine propel system 204 in any suitable form, such as, but not limited to, mechanical power from a rotating shaft, electrical power that is generated by an electrical power generator or stored in the form of electrical power in batteries, capacitors, or other storage devices and so forth.

The machine propel system 204 may include one or more motors (not shown) that are arranged to rotate or otherwise actuate components that drive the ground engaging members 106 of the machine 100. Additionally, or alternatively, the machine propel system 204 may include one or more clutches or gear packs, for example, bevel gears, planetary gear sets, track sprockets, and so forth, that transmit power from the engine 114 in a direct drive configuration to power the ground engaging members 106 to propel the machine 100.

Further, the engine 114 may be configured to power one or more implements of the machine 100, which may be collectively referred to as a machine implement system 206 of the machine 100. The machine implement system 206 may include any known type of actuator(s) that uses a power input to perform a function. Such power input may be converted into mechanical power that operates a device or implement that performs a function of the machine. In the illustrated, the engine 114 may provide power in the form of mechanical power operating a hydraulic pump (not shown) of the hydraulic system 148 that provides a flow of pressurized fluid to cause motion of the actuators 132, 142, 144, 146.

Each of the machine propel system 204 and the machine implement system 206 may be communicatively coupled to the electronic controller 202. For instance, the electronic controller 202 may provide propel commands, commands and settings to the machine propel system 204, such as an operator command to propel the machine, which may include an actuation signal for one or more motors. The machine propel system 204 may also provide information, such as torque or power consumption of the machine propel system 204 in real time during operation, the speed of operation of the one or more motors, and so forth to the electronic controller 202. Similarly, the electronic controller 202 may provide command signals to operate the various implements associated with the machine implement system 206 and the machine implement system 206 may provide information about the operation of the various implements, such as torque or power utilization, to the electronic controller 202. The engine 114 may additionally be configured to power other systems 208 of the machine 100. Such other systems 208 may include any suitable auxiliary power generation system used to provide power to one or more auxiliary components of the machine 100, such as, but not limited to, fans 210-1, blowers 210-2, air-conditioning compressors 210-3, lights 210-n, and/or other machine systems onboard the machine 100. Such other systems 208 may also be configured to received one or more operational commands from the electronic controller 202 and send information about power consumption to the electronic controller 202.

During operation of the power system 200, information about torque or power utilization by the various systems, for example, the machine propel system 204, the machine implement system 206, and/or the other systems 208, is received and processed by the electronic controller 202. Such processing of information may include various operations, including an aggregation of power utilization in the power system 200 indicative of a total power utilization in the machine 100 in real time. The electronic controller 202 is further configured to control the operations of the engine 114 based on the power utilization information of the various systems of the machine 100. For example, the electronic controller 202 is configured to provide command signals to various engine actuators and systems that control the operation of the engine 114. As is known, the electronic controller 202 is configured to control engine speed and power by, for example, controlling the amount of fuel or air that enters the engine 114. Such engine control is typically based on various engine operating parameters, such as engine speed. Information signals that are indicative of one or more engine operating parameters are provided to the electronic controller 202.

The electronic controller 202 is configured to receive operational commands from an operator of the machine 100 via one or more operator control devices 212 positioned within an operator cabin, such as the operator cabin 108 of the machine 100. The operator control device 212 may be any device known in the art for causing a machine function in response to a manual command performed on the control device 212 by the operator of the machine. Such operator control devices 212 may include pedals, levers, joysticks, steering wheels, switches, knobs, and so forth. For the purpose of explanation, the operator control device 312 is described as a throttle pedal that may be used by the operator to provide throttle actuation signal to control the engine speed during operation of the machine 100.

In an embodiment of the present disclosure, the power system 200 includes an engine mode switch 214 for facilitating on the fly switching of operating modes of the engine 114. For example, the engine mode switch 214 is a two-position switch positioned inside the operator cabin 108 of the machine 100, such as on the operator console 152 or an auxiliary console (not shown) provided inside the operator cabin 108. The engine mode switch 214 may define a first switch position corresponding to a first operating mode of the engine 114 and a second switch position corresponding to a second operating mode of the engine 114. The engine mode switch 214 may be configured to facilitate the operator of the machine 100 to switch between the operating modes of the engine 114 according to engine performance requirements. The details of the first operating mode and the second operating mode of the engine 114 and the operations of the electronic controller 202 and the engine 114 in response to operator selection will now be described in greater detail with reference to FIGs. 3 through 8.

As shown in FIG. 3, the electronic controller 202 includes a control unit 300, an input/output unit 302, and a memory unit 304 communicatively coupled to one another. The input/output unit 302 is configured to receive inputs from the various machine systems, operator control device 212 and the engine mode switch 214 to facilitate controlling of operations of the engine 114 by the control unit 300 based on one or more engine operating parameters stored in the memory unit 304. The memory unit 304 may include a random access memory (RAM) and read only memory (ROM). The RAM may be implemented by Synchronous Dynamic Random Access Memory (SDRAM), Dynamic Random Access Memory (DRAM), and/or any other type of random access memory device. The ROM may be implemented by a hard drive, flash memory and/or any other desired type of memory device. Further, the control unit 300 may be configured to execute the instruction stored in the memory unit 304, to perform the one or more predetermined operations, such as those described herein. The control unit 300 may include one or more microprocessors, microcomputers, microcontrollers, programmable logic controller, DSPs (digital signal processors), central processing units, state machines, logic circuitry, or any other device or devices that process/manipulate information or signals based on operational or programming instructions. The control unit 300 may be implemented using one or more controller technologies, such as Application Specific Integrated Circuit (ASIC), Reduced Instruction Set Computing (RISC) technology, Complex Instruction Set Computing (CISC) technology, etc.

The electronic controller 202 is configured to store predefined engine maps corresponding to the first operating mode and the second operating mode of the engine 114. For example, the electronic controller 202 is configured to store a first engine map corresponding to the first operating mode 400 (shown in FIG. 4) of the engine 114 and a second engine map corresponding to the second operating mode 500 (shown in FIG. 5) of the engine 114. The engine maps represents an interrelationship between an engine speed 402, 502, which is expressed, for example, in revolutions per minute (RPM), and a torque output 404, 504 of the engine 114, which can be expressed in Nm or ft-lb. The interrelationship between the engine speed and the torque in each of the first engine map and the second engine map govern the operations of the engine 114 in the first operating mode 400 and the second operating mode 500, respectively as load on the engine 114 increases during operation.

In an exemplary embodiment of the present disclosure, the first operating mode 400 of the engine 114 is an isochronous operating mode (hereinafter interchangeably referred to as the isochronous operating mode 400) while the second operating mode 500 of the engine 114 is a droop operating mode (hereinafter interchangeably referred to as the droop operating mode 500).

In an isochronous operating mode 400 of the engine 114, the engine speed is adjusted to match a desired engine speed (target speed), in response to throttle actuation signal received from the operator control device 212, by adjusting fuel supply to the engine 114 when load on the engine 114 changes. Thus, in an isochronous operating mode 400, when load is applied to the engine 114, the electronic controller 202 may be configured to increase the fuel supply to the engine 114 to match the actual engine speed with the target speed in response to throttle actuation by the operator of the machine 100. Similarly, when the load is decreased, the electronic controller 202 may be configured to decrease the fuel supply to the engine 114 to decrease the engine speed and match the actual engine speed to the target engine speed in response to the throttle actuation by the operator.

FIG. 4 illustrates an engine map 400 having engine speed plotted along the horizontal axis 402 and engine torque output plotted along the vertical axis 404. A curve 406 represents the maximum attainable engine torque over the range of operating engine speed. For purpose of illustration, a desired engine speed 408 is identified on the engine map 400. The desired engine speed 408 may represent a desired speed for the engine under conditions of little to no load utilization. During operation, the electronic controller 202 may control the operation of the engine 114 such that the engine speed is maintained constant until the engine 114 reaches its rated power output or rated torque output 410 in response to an increase in the load on the engine 114. Thus, in the first operating mode or the isochronous mode 400, the constant speed extends along a vertical line 412 corresponding to the desired engine speed 408 as the load on the engine 114 changes from no-load to full load, for example, when the machine 100 performs one or more machine and/or implement operations at the worksite 102. In the illustrated example, when the desired engine speed 408 is 2300 RPM, the electronic controller 202 may be configured to adjust fuel supply to the engine 114, so that the engine speed is maintained at 2300 RPM (along the vertical line 412) as the load on the engine changes from no-load to full load and the engine 114 reaches the rated power output.

In the second operating mode or the droop operating mode 500 of the engine 114, the electronic controller 202 is configured to facilitate a percentage reduction (hereinafter referred to as droop) in the engine speed as the load on the engine 114 increases. For instance, if the droop percentage is defined as 5%, then with 5% reduction in the engine speed, the operating power output of the engine 114 is increased by 100 %. Accordingly, with every 1% decrease in engine speed, the power output is increased by 20%. In droop operation mode 500, the engine speed decreases by a set percentage after a load has been applied. Therefore, in the droop operating mode, if the original speed is desired, the operator must raise the speed setting to return to the original speed when a load is applied. For example, droop is expressed as a percentage of the original speed setting from no load to full load and is determined based on the following relation:

(iVo Load engine speed — Full load rated speed )

% Droop X 100 Full load rated speed

FIG. 5 illustrates the second operating mode or the second engine map 500 having engine speed plotted along the horizontal axis 502 and engine torque output plotted along the vertical axis 504. A curve 506 represents the maximum attainable engine torque over the range of operating engine speed. For purpose of illustration, a no-load engine speed 508 is identified on the engine map 500. The no-load engine speed 508 may represent a desired speed for the engine under conditions of little to no load utilization. In an exemplary embodiment, in the droop operating mode 500, the electronic controller 202 may facilitate the engine speed to decrease according to a predefined percentage droop setting (following the slope 510) in response to throttle actuation signal until the engine 114 reaches the rated power output (i.e., the full load rated speed 512) as the load on the engine 114 changes from no-load to full load. Therefore, in the droop operating mode 500, the no-load engine speed 508 may be set to be higher than the full load rated speed 512, such that when the engine speed follows the percentage droop, the engine 114 reaches the desired full load rated speed 504. In one example, as shown in FIG. 5, the no-load speed is set to be 2460 RPM and the full load rated speed is set to be 2300, thereby facilitating a reduction of about 7% in the engine speed when the load changes from no-load to full-load.

This means that in the droop operating mode 500, the electronic controller 202 will not adjust the fuel supply to the engine to increase the engine speed, as in the isochronous mode 400. Instead, the electronic controller 202 will allow the engine speed to decrease by a set percentage when the load on the engine 114 increases at least until the engine 114 reaches its rated power.

Referring back to FIG. 3, the control unit 300 includes a load detection unit 306, a mode detection unit 308, an operations control unit 310, a comparator 312 and a fuel adjustment unit 314. The load detection unit 306 is configured to continuously receive information about the load on the engine 114 based on the power utilization information received from the various machine systems. The load detection unit 306 may be further configured to detect the change in load on the engine 114 from no-load to full-load to subsequently govern the engine operations.

In an embodiment of the present disclosure, the mode detection unit 308 may be operatively coupled to the engine mode switch 214 inside the operator cabin 108 and configured to detect the operating mode of the engine 114 corresponding to the position of the engine mode switch 214. In an exemplary embodiment, the mode detection unit 308 may be configured to detect a current operating mode of the engine 114 as well as a desired or changed operating mode of the engine 114 based on the operator input received from the engine mode switch 214. For instance, the mode detection unit 308 may be configured to detect a change in the operating mode of the engine 114 when the operator provides the operator input by changing the position of the engine mode switch 214.

Further, the operation control unit 310 is configured to control the engine 114 in accordance with the engine map corresponding to the detected operating mode. For example, the operation control unit 310 is configured to adjust the engine speed based on the operating mode of the engine 114 as detected by the mode detection unit 308. For example, when the engine mode switch 214 is positioned to first switch position, thereby indicating to the mode detection unit 308 that the detected operating mode is the first or the isochronous mode, the operation control unit 310 starts to control the engine 114 and govern the engine speed according to the engine map 400. To this end, as the load is applied to the engine 114, the operation control unit 310 is configured to activate the comparator 312 to compare an actual engine speed at which the engine 114 is operating, in response to the throttle actuation signal received from the operator control device 212, to the desired engine speed at which the engine 114 is desired to be operating in response to the throttle actuation signal received from the operator control device 212. For instance, the comparator 312 may be configured to communicate with an engine speed sensor 316 associated with the engine 114 to continuously detect the actual engine speed at which the engine 114 is operating. Based on the comparison, if the actual engine speed is determined to be different than the desired engine speed, the fuel adjustment unit 314 may be configured to adjust a fuel supply to the engine 114 to maintain the engine speed constant and equal to the desired engine speed (in accordance with the vertical line 412) as the load changes from no-load to full-load. Thus, when the load increases, by default, the engine speed tends to decrease and the fuel adjustment unit 314 may be configured to increase the fuel supply to the engine 114 until the engine speed reaches and is maintained at the desired engine speed. Similarly, when the load decreases or otherwise when the actual engine speed is determined to be higher than the desired engine speed, the fuel adjustment unit 314 may be configured to reduce the fuel supply to the engine 114 until engine speed is reduced and maintained at the desired engine speed.

Further, during operation, the operator of the machine 100 may switch the position of the engine mode switch 214 to switch the engine operating mode to the second operating mode, i.e., the droop operating mode 500. For instance, in order to perform implement operations while the machine 100 is not moving, the operator of the machine 100 may want to run the engine 114 in the droop operating mode 500 to save fuel. Thus, the operator may switch the engine mode switch 214 to the second switch position thereby switching the engine 114 to operate in the droop operating mode 500 on the fly without switching off the engine 114. For example, the mode detection unit 308 may be configured to detect that the operator input indicates a change in position of the engine mode switch 214 and thus the operating mode of the engine 114. For instance, the mode detection unit 308 may determine the current operating mode of the engine 114 to be the first operating mode 400 and detect that changed position of the engine mode switch 214 indicates a change in operating mode from the first operating mode 400 to the second operating mode 500.

In an embodiment of the present disclosure, in response to the detected change in operating mode, the operation control unit 310 automatically switches the operating mode of the engine 114 and starts controlling the engine 114 according to the engine map corresponding to the second operating mode or droop operating mode 500. To this end, the operation control unit 310 may be configured to send a deactivation signal to the comparator 312 so as to stop adjusting the engine speed and fuel supply to the engine 114. Therefore, once the operating mode of the engine 114 is switched to the droop operating mode 500, the no-load engine speed is changed to be higher than the full load rated speed and the operations control unit 310 controls the engine 114 to facilitate the decrease in engine speed by predefined droop percentage to accommodate the increase in load on the engine 114. For example, the droop percentage may be predefined and prestored in the memory unit 304. In an exemplary implementation, the predefined droop percentage may be defined between 3% to 15%. However, the values of the predefined droop percentage are merely exemplary and may be varied without deviating from the scope of the claimed subject matter.

Furthermore, when the operator switches the engine mode switch 214 back to the first switch position corresponding to the first operating mode 400, then the mode detection unit 308 again detects this change and accordingly the operations control unit 310 automatically switches the engine operating mode from the second operating mode 500 back to the first operating mode 400. Thus, the operation control unit 310 again activates the comparator 312 and starts controlling the engine 114 in the manner already described above.

Industrial Applicability

The power system 200 and the electronic controller 202 of the present disclosure facilitates on the fly and automatic switching of operating modes of the engine 114 between the first operating mode, i.e., isochronous operating mode 400 and the second operating mode, i.e., droop operating mode 500 to achieve fuel efficiency without switching off the engine 114. Such dynamic and automatic switching is facilitated by the two-position engine mode switch 214 which defines two switch positions, i.e., the first switch position corresponding to the isochronous operating mode 400 and the second switch position corresponding to the droop operating mode 500. In an exemplary implementation, the first switch position may be labelled as “Normal mode” and the second switch position may be labelled as “Eco mode” on the engine mode switch 214 for the convenience of understanding of the operator of the machine 100. As explained previously, the engine mode switch 214 may be positioned on either a main console, such as the console 152 or on an auxiliary console (not shown) provided on either side of the operator seat 150 to facilitate ease of operation for the operator.

Fig. 6 illustrates an exemplary method 600 of controlling operations of the engine 114. Fig. 7 illustrates an exemplary graph indicating the changes in engine speed in response to increase in load, as governed by the first operating mode 400. Fig. 8 illustrates an exemplary graph indicating the changes in engine speed in response to increase in load, as governed by the second operating mode 500.

As the machine 100 is operated at the worksite 102, the operator may also select the operating mode of the engine 114. For example, the operation control unit 310 within the electronic controller 202 is configured to operate the engine 114 in one of the first operating mode 400 or the second operating mode 500, at step 602. For example, the mode detection unit 308 is configured to detect the position of the engine mode switch 214 and accordingly detect the operating mode of the engine 114. For instance, when the machine 100 is moving and operating at the worksite 102, the operator may select the “Normal mode” of engine mode switch 214 thereby indicating the engine operating mode as the first operating mode 400 to the mode detection unit 308. Upon such detection by the mode detection unit, the operation control unit 310 may be configured to operate the engine 114 in the isochronous operating mode 400. Thus, in the illustrated example shown in FIG. 7, the engine speed 702 follows the almost straight line 710 and thus is maintained constant and close to the rated speed 712 by adjusting the fuel supply to the engine 114. As will be appreciated, the engine torque output is shown along the vertical axis 704 and the curve 706 represents the maximum attainable engine torque over the range of operating engine speed. For example, the full-load rated speed 712 of the engine 114 is set to be 2200 RPM and thus, as the load on the engine 114 increases, the operator will initially observe a drop in the engine speed and try to compensate by increasing the throttle actuation through the operator control device 212. At the same time, the operation control unit 310 may activate the comparator 312 to detect that the actual engine speed is less than the desired engine speed. Accordingly, the fuel adjustment unit 314 adjusts the fuel supply to the engine 114 to increase the engine speed corresponding to the throttle actuation signal and maintain the engine speed as close as possible to the desired full -load rated speed of 2200 RPM, thereby following the almost vertical line 710 shown in FIG. 7.

While the engine 114 is still running, the operator may desire to switch the engine operation to “Eco mode”, for example, when the machine 100 is not moving and performing implement operations at the worksite 102. Thus, the operator may switch the position of the engine mode switch 212 from the previous first position (the “Normal mode” position) to the second position (the “Eco mode” position). The mode detection unit 308 receives this operator input indicating a change in the operating mode of the engine 114, at step 604.

Further, at step 606, the mode detection unit 308 determines the current operating mode of the engine 114 in which the engine 114 is currently operating. Thus, when the operator input is received, the mode detection unit 308 that the engine 114 is currently operating in the first operating mode, i.e., the isochronous operating mode and thus determines that the received operator input indicates a different operating mode of the engine 114.

At step 608, the operation control unit 310 controls the engine 114 to automatically switch the operating mode to the other of the first operating mode or the second operating mode based on the received operator input and the determined current operating mode of the engine 114. For example, in this case, the operation control unit 308 automatically switches the engine map to the engine map corresponding to the droop operating mode 500 to control the engine 114 operations in accordance with the droop operating mode 500.

At step 610, the engine speed is controlled or governed according to the engine map corresponding to the droop operating mode 500, as described above. For example, as shown in FIG. 8, the full-load engine rated speed 812 is set as 2200 RPM while the no-load engine speed 808 is set at 2350 RPM. As will be appreciated, the engine torque output is shown along the vertical axis 804 and the curve 806 represents the maximum attainable engine torque over the range of operating engine speed. In this example, as the load changes from no-load to full load, the engine speed 802 decreases by a predefined percentage to follow the slope 810 and accommodate the load changes without increasing the fuel supply to the engine 114. Thus, the droop operating mode 500 is able to accommodate loads with reduced fuel consumption by the engine 114 and thus provides fuel efficiency for the machine 100.

The method 600 may be performed repeatedly during the operation of the machine 100 and may facilitate on the fly switching of operating modes of the engine 114 to achieve fuel efficiency. The power system 200 and the electronic controller 202 add versatility to the machines by facilitating easy switching between performance and fuel related operations of the machine. In an exemplary implementation, such electronic controller 202 and the engine mode switch 214 may be provided as retrofittable components to be retrofitted onto the existing power system of a machine. Since the electronic controller 202 facilitates switching the operating modes of the engine 114, it can be implemented onto machines that do not have a dedicated electronic control module for the various components of the machine and still achieve fuel efficiency without complex structural alterations to the machine.

It will be apparent to those skilled in the art that various modifications and variations can be made to the system of the present disclosure without departing from the scope of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalent.

Claims

1. A method (600) for controlling operations of an engine (114) of a machine (100), the method (600) comprising: operating (602), by an electronic controller (202), the engine (114) in one of a first operating mode and a second operating mode, the first operating mode being an isochronous operating mode facilitating adjusting an engine speed to match a target engine speed corresponding to a change in engine load from no- load to full load and the second operating mode being a droop operating mode facilitating a predefined decrease in the engine speed corresponding to the change in engine load from no-load to full load; receiving (604), by the electronic controller (202) via an engine mode switch (214), an operator input indicating a change in the operating mode of the engine (114); determining (606), by the electronic controller (202), a current operating mode of the engine (114); and controlling (608), by the electronic controller (202), the engine (114) to change the operating mode from one of the first operating mode and the second operating mode to the other of the first operating mode and the second operating mode based on the received operator input and the determined current operating mode of the engine (114); and controlling (610), by the electronic controller (202), the engine speed in accordance with the changed operating mode of the engine (114) corresponding to the change in engine load.

2. The method (600) as claimed in claim 1, wherein the engine mode switch (214) is a two-position switch positioned inside an operator cabin (108) of the machine (100) and operatively coupled to the electronic controller (202), the two-position switch defining a first switch position corresponding to the first operating mode and a second switch position corresponding to the second operating mode of the engine (114). 3. The method (600) as claimed in claim 1 , wherein the second operating mode includes a predefined engine map indicative of a predefined droop percentage from no-load engine speed to full-load engine speed and wherein controlling the engine speed comprises decreasing, by the electronic controller (202), the engine speed according to the predefined droop percentage corresponding to an increase in engine load when the engine (114) is controlled to change the operating mode from the first operating mode to the second operating mode. 4. The method (600) as claimed in claim 3, wherein the predefined droop percentage is within a range of 3 percent to 15 percent.

5. The method (600) as claimed in claim 1, wherein when the engine (114) is controlled to change the operating mode from the second operating mode to the first operating mode, controlling the engine speed comprises: determining, by the electronic controller (202) via an operator control device (212), a desired engine speed based on a throttle actuation signal and the engine load; determining, by the electronic controller (202) using an engine speed sensor (316), an actual engine speed corresponding to the throttle actuation signal and the engine load; comparing, by the electronic controller (202), the desired engine speed and the actual engine speed; and adjusting, by the electronic controller (202), based on the comparison, a fuel supply to the engine (114) to adjust the engine speed to match the target engine speed corresponding to the change in engine load.

6. A power system (200) for controlling operations of an engine (114) of a machine (100), the power system (200) comprising: an engine mode switch (214) positioned within an operator cabin

(108) of the machine (100) and configured to selectively activate one of a first operating mode or a second operating mode of the engine (114), the first operating mode being an isochronous operating mode facilitating adjusting an engine speed to match a target engine speed corresponding to a change in engine load from no- load to full load and the second operating mode being a droop operating mode facilitating a predefined decrease in the engine speed corresponding to the change in engine load from no-load to full load; and an electronic controller (202) operatively coupled to the engine mode switch (214) and the engine (114), the electronic controller (202) being configured to: operate the engine (114) in one of the first operating mode or the second operating mode based on an activated operating mode; receive an operator input via the engine mode switch (214), the operator input indicating a change in the operating mode of the engine (114); determine a current operating mode of the engine (114); control the engine (114) to change the operating mode from one of the first operating mode and the second operating mode to the other of the first operating mode and the second operating mode based on the received operator input and the determined current operating mode of the engine (114); and control the engine speed in accordance with the changed operating mode of the engine (114) corresponding to the change in engine load.

7. The power system (200) as claimed in claim 6, wherein the engine mode switch (214) is a two-position switch having a first switch position corresponding to the first operating mode and a second switch position corresponding to the second operating mode of the engine (114).

8. The power system (200) claimed in claim 6, wherein the second operating mode includes a predefined engine map indicating a predefined droop percentage from no-load engine speed to full-load engine speed and wherein the electronic controller (202) is configured to: decrease the engine speed according to the predefined droop percentage corresponding to an increase in engine load when the engine (114) is controlled to change the operating mode from the first operating mode to the second operating mode.

9. The power system (200) as claimed in claim 8, wherein the predefined droop percentage is within a range of 3 percent to 15 percent.

10. The power system (200) as claimed in claim 6, further comprising: an operator control device (212) positioned within the operator cabin (108) of the machine (100) and configured to receive a throttle actuation signal for controlling the engine speed; an engine speed sensor (316) associated with the engine (114) and configured to sense the engine speed; and wherein when the engine (114) is controlled to change the operating mode from the second operating mode to the first operating mode, the electronic controller (202) is configured to: determine a target engine speed based on the throttle actuation signal and the engine load; determine, using the engine speed sensor (316), an actual engine speed corresponding to the throttle actuation signal and the engine load; compare the target engine speed and the actual engine speed; and adjust a fuel supply, based on the comparison, to control the engine speed to match the target engine speed corresponding to the change in engine load from no-load to full load.