Patent Description:
Working machines of various types such as excavators, backhoe loaders, wheel loading shovels, telescopic handlers, tractors, material handling and the like used in various applications in construction, agriculture, logistics and waste handling and recycling have historically been powered by internal combustion engines (ICEs), for example diesel engines.

Due to increasing concerns regarding climate change and air quality, legislation has been enacted that is resulting in a drive towards alternative power sources for such machines. One such power source is electrical energy stored in batteries or other storage media that is used to provide energy to electric motors to operate such working machines. The batteries may be used as the sole source of power to the machine, or may be used in conjunction with an ICE in a so called "hybrid" configuration whereby power may be supplied from the battery to the electric motors alone, energy may be supplied from diesel fuel to power an internal combustion engine alone, or some combination of the two power sources may be utilised. In such hybrid configurations, typically a smaller ICE will be provided than on a traditional machine with the power shortfall being supplied from the batteries and electric motor.

Traditional energy sources such as diesel fuel have a greater energy density than batteries, i.e. one unit mass of the fuel is able to supply more energy compared to a unit mass of a battery. Diesel fuel is generally lower cost than batteries or other electrical energy storage media. Batteries also take significantly longer to charge than an ICE engine takes to refuel, potentially leading to a loss of productivity.

In addition, ICEs produce a significant amount of waste heat in operation that may be utilised for heating parts of the working machine as required, such as the operator structure. Such a source of heat may be reduced in a hybrid working machine, or be entirely non-existent in a solely electrically powered working machine.

During certain stages of a typical operating cycle of a working machine, and being dependent upon environmental conditions, certain parts of a working machine may desirably be heated or cooled to maintain operating efficiency and operator comfort. The supply of energy to effect such heating or cooling may be problematic in certain circumstances in a pure electric working machine or a hybrid working machine in view of the reduced availability or quality of energy and waste heat to provide such heating or cooling. In particular the use of electrical energy from the machine's batteries to provide such heating or cooling may reduce the available energy for such a machine to perform working operations, between periods of charging where the machine may not be operable, thereby compromising the working efficiency of the machine. Utility model <CIT> discloses a mobile crane hydraulic tank's medium temperature governing system.

The present teachings seek to overcome or at least mitigate the problems of the prior art.

According to a first aspect, there is provided a working machine comprising: an electric energy storage unit configured to provide electrical power to the working machine; a hydraulic fluid circuit arranged to provide hydraulic fluid to one or more hydraulic actuators to perform a working operation; an operator structure; an operator structure climate control assembly arranged to selectively add and/or remove thermal energy to/from the operator structure for selectively warming and cooling the operator structure; a heat exchanger arranged to selectively add and/or remove thermal energy from the hydraulic fluid circuit for selectively warming and cooling the hydraulic fluid; and a thermal management system connecting the heat exchanger to the operator structure climate control assembly, wherein the thermal management system is configured to determine an operator structure energy requirement based on a target operator structure temperature and a hydraulic fluid energy requirement based on a target hydraulic fluid temperature, and wherein the thermal management system comprises an energy distribution system to selectively transfer thermal energy between the operator structure and the hydraulic fluid based on the relative values of the operator structure energy requirement and the hydraulic fluid energy requirement; and wherein the thermal management system is configured to heat the hydraulic fluid and/or operator structure to the respective target temperature(s) prior to or at an expected time of operation of the working machine.

Advantageously, this arrangement enables excess thermal energy in the hydraulic fluid to be used to heat the operator structure and/or vice versa, and therefore increases the efficiency of the working machine. Using an energy requirement calculation for the operator structure and the hydraulic fluid as opposed to absolute temperature values is advantageous in determining the amount and the rate of heat transfer required between the hydraulic fluid and the operator structure.

The provision of an energy distribution system allows heat transfer to occur more efficiently in certain conditions, for example when thermal energy is transferred from an operator structure that is cooler than the hydraulic fluid, but the operator structure has an energy surplus and the hydraulic fluid has an energy deficit. This arrangement provides a time, e.g. input by an operator, by which the hydraulic fluid and/or operator structure should be heated by. This enables the hydraulic fluid and/or operator structure to be heated just in time for use by an operator, which avoids the system maintaining the target temperatures unnecessarily. This helps to improve the efficiency of the thermal management system.

The energy distribution system of the thermal management system may be configured to activate when the working machine is in an active state.

The working machine is considered to be in an active state when it is turned on, e.g. before or during use by an operator, and when it is charging. The provision of an energy distribution system that operates when the machine is active enables said system to preheat the operator structure and/or hydraulic fluid prior to use by an operator.

When the working machine is in an active state, i.e. when the working machine is turned on or is charging, this arrangement helps pre heat the hydraulic fluid and/or operator structure. This helps to ensure that the hydraulic fluid is operating at an optimal viscosity to increase the efficiency of the working operations and/or to improve user comfort within the operator structure. Providing a thermal management system that will supply heat when the machine is in an active state (i.e. when the machine is either running or charging) ensures that the additional supplied energy does not have to come from an electrical energy storage device.

The expected time of operation may be inputted by an operator.

The thermal management system may be configured to calculate the expected time of operation of the working machine from a mean value of times at which the working machine is turned on over a pre-determined period of time.

Incorporating machine learning may improve the efficiency of the thermal management system because thermal energy is not wasted maintaining the hydraulic fluid and operator structure at their target temperatures.

The thermal management system may be configured to activate such that the time at which the hydraulic fluid and/or operator structure are preheated to their respective target temperatures is approximately equal to the expected time of operation.

This arrangement helps to ensure that the operator structure and hydraulic fluid of the working machine are only preheated for the desired time, which avoids waste energy being used by holding the operator structure and hydraulic fluid at their target temperatures during a whole charging cycle.

The energy distribution system may be configured to impart thermal energy into the thermal management system when transferring thermal energy between the operator structure and the hydraulic fluid. The thermal management system may be configured to transfer this imparted energy to hydraulic fluid and/or operator structure.

Utilisation of the energy put into the thermal management system by the energy distribution system to heat the operator structure and/or hydraulic fluid has been found to improve the efficiency of the thermal management system, and so of the working machine.

The thermal management system may be configured to determine whether the working machine has an energy surplus or an energy deficit based on the operator structure energy requirement and the hydraulic fluid energy requirement.

Calculation of whether the working machine has an energy surplus or an energy deficit (i.e. calculation of the energy requirement of the working machine) allows the thermal management system to determine whether there is a need to add or remove thermal energy from the working machine, depending on whether there is an energy deficit or an energy surplus within the working machine. This has been found to improve the efficiency of the system, and so of the working machine.

The thermal management system may be configured to determine whether the working machine has an energy surplus or an energy deficit based on the thermal energy imparted into the thermal management system when transferring thermal energy between the operator structure and the hydraulic fluid.

Incorporating the energy supplied by energy distribution system into the machine energy requirement calculation improves the accuracy of the energy requirement calculation. This has been found to improve the efficiency of the thermal management system, and so of the working machine.

When the working machine is determined to have an energy surplus, the thermal management system may be configured to selectively remove thermal energy from the hydraulic fluid and/or the operator structure and to direct the surplus thermal energy to ambient or to transfer the surplus thermal energy to a component of the working machine, e.g. to transfer the surplus thermal energy to an electric energy storage device, an electric heater and/or an electric motor for providing, at least in part, tractive power to the working machine.

This arrangement may further optimise the usage of thermal energy in the working machine.

The energy distribution system may comprise a heat pump circuit. The heat pump circuit or refrigerant circuit may include a compressor for compressing a refrigerant in the heat pump circuit and optionally including an expansion device, an evaporator and a condenser.

This arrangement enables the energy transfer system to selectively transfer heat from a source to a target, even when the source temperature is below the required temperature of the target.

The energy distribution system may be configured to determine whether the working machine has an energy surplus or an energy deficit based on the energy added to the refrigerant by the compressor.

This has been found to increase the accuracy of the energy requirement calculation.

The energy distribution system may comprise a coolant circuit having a coolant flow path in thermal communication with the operator structure and the hydraulic fluid for transferring thermal energy therebetween, optionally wherein the coolant flow path is in thermal communication with the hydraulic fluid heat exchanger and the operator structure climate control assembly.

The coolant circuit may comprise a coolant pump for circulating coolant around the coolant flow path.

The energy distribution system may be configured to determine whether the working machine has an energy surplus or an energy deficit based on thermal energy in the coolant. The energy distribution system may be configured to determine whether the working machine has an energy surplus or an energy deficit based on the volume and/or specific heat capacity of the coolant.

The electric heater may be configured to impart thermal energy into the coolant, e.g. when the working machine is charging.

The thermal energy in the hydraulic fluid and/or the coolant may be used to pre-heat the operator structure.

The working machine may comprise an electric heater arranged to supply thermal energy to the thermal management system. The electric heater may enable the thermal management system to pre-heat the hydraulic fluid and/or the operator structure.

This arrangement may enable the pre-conditioning of the hydraulic fluid and/or operator structure to occur prior to operation of the working machine. Additionally, this may allow thermal energy to be added to the energy distribution system when there is insufficient thermal energy to heat the hydraulic fluid and/or the operator structure.

The working machine may comprise an outside heat exchanger configured to liberate thermal energy from the atmosphere and/or to supply thermal energy to the thermal management system.

This has been found to improve the efficiency of the thermal management system, and so of the working machine.

The thermal management system may be configured to determine the operator structure energy requirement based on a measured operator structure temperature and a target operator structure temperature and/or to determine the hydraulic fluid energy requirement based on a measured hydraulic temperature and a target hydraulic fluid temperature.

Inputting the measured value for hydraulic fluid temperature may improve the efficiency of heat transfer if the operator structure is above or below the target temperature. Additionally, using a measured value increases the accuracy of the hydraulic fluid energy requirement.

The thermal management may be configured to determine the operator structure energy requirement and/or hydraulic fluid energy requirement based on a measured ambient temperature.

Inputting the ambient temperature into the energy requirement calculation tells the thermal management system if there is thermal energy available to be absorbed from ambient. Additionally, the accuracy of the operator structure energy requirement may increase because if the ambient temperature is lower than the measured operator structure temperature, the rate of thermal energy transferred to ambient is accounted for.

The thermal management system may be configured to determine the operator structure energy requirement based on a solar load imparted onto the operator structure.

Inputting the solar load may improve the efficiency of the system because it inhibits energy being extracted unnecessarily, for example to heat the operator structure, when energy is available from the solar load.

The operator structure operator structure climate control assembly may comprise an operator structure heat exchanger configured to selectively add thermal energy to the operator structure and/or an operator structure cooler configured to selectively remove thermal energy from the operator structure.

The working machine may further comprise an electrical energy storage device configured to provide, electrical energy to an electric motor to provide, at least in part, tractive power to the ground engaging propulsion structure and/or power to a hydraulic pump to provide pressurised hydraulic fluid to displace the or each hydraulic actuator.

The thermal management system may be arranged to supply thermal energy to and/or remove thermal energy from at least one of: an electric motor to provide tractive power to the ground engaging structure, an electric motor to drive a hydraulic pump of the hydraulic fluid circuit, power electronics of the working machine; and the electrical energy storage device.

According to a second aspect, there is provided a method for transferring thermal energy around a working machine comprising an electric energy storage unit configured to provide electrical power to the working machine using a thermal management system, the method comprising the steps of: a) determining an operator structure energy requirement based on a target operator structure temperature; b) determining a hydraulic fluid energy requirement based on a target hydraulic fluid temperature; c) calculating a working machine energy requirement based on the operator structure energy requirement and the hydraulic fluid energy requirement; d) selectively transferring thermal energy between the operator structure and the hydraulic fluid based on the operator structure energy requirement and the hydraulic fluid energy requirement; and e) heating the hydraulic fluid (<NUM>) and/or the operator structure (<NUM>) to the respective target temperature(s) (<NUM>, <NUM>) prior to or at an expected time of operation of the working machine.

This method helps ensure that the hydraulic fluid is operating at an optimal viscosity to increase the efficiency of the working operations and thereby maximise the operations that may be undertaken between recharging operations of the electrical energy storage device. Additionally, the overall efficiency of the working machine is further improved since less electrical energy is used to effect operator structure heating.

The method may further comprise the step of determining whether a working machine has an energy surplus or an energy deficit based on the operator structure energy requirement and the hydraulic fluid energy requirement.

The method may carried out only when the working machine is in an active state.

According to an example, there is provided a working machine comprising: a hydraulic fluid circuit arranged to provide hydraulic fluid to one or more hydraulic actuators to perform a working operation; an operator structure; an operator structure climate control assembly arranged to selectively add and/or remove thermal energy to/from the operator structure for selectively warming and cooling the operator structure; a heat exchanger arranged to selectively add and/or remove thermal energy from the hydraulic fluid circuit for selectively warming and cooling the hydraulic fluid; and a thermal management system connecting the heat exchanger to the operator structure climate control assembly, wherein the thermal management system is configured to preheat the hydraulic fluid and/or operator structure to respective target temperature(s) prior to or at an expected time of operation of the working machine.

This arrangement provides a start time, e.g. input by an operator, by which the hydraulic fluid and/or operator structure should be heated by. This enables the hydraulic fluid and/or operator structure to be heated just in time for use by an operator, which avoids the system maintaining the target temperatures unnecessarily. This helps to improve the efficiency of the thermal management system.

It will be appreciated that the fourth aspect may also comprise one or more of the features of the first aspect.

Embodiments disclosed herein will now be described, by way of example only, with reference to the accompanying drawings, in which:.

With reference to <FIG>, an embodiment includes a working machine <NUM> which may be a load handling machine. In this embodiment the load handling machine is a telescopic handler. In other embodiments the working machine <NUM> may be a skid-steer loader, a compact track loader, a wheel loader, or a telescopic wheel loader, a slew excavator, a backhoe loader, a dumper or a tractor for example. Such machines may generally be denoted as off-highway working machines. All such machines include a hydraulic fluid circuit arranged to provide hydraulic fluid to one or more hydraulic actuators for performing working operations such as moving a working arm of a loader or excavator; tipping a skip of a dumper; or lifting or powering an implement of a tractor.

The machine <NUM> includes a machine body <NUM>. The body <NUM> may include an operator structure <NUM> to accommodate a machine operator, for example, an enclosed operator structure from which an operator can operate the machine <NUM>. The working environment in the operator structure <NUM> can be separate from its surroundings. In other embodiments, the working machine <NUM> may have an open canopy structure (not shown) for the operator.

In an embodiment, the machine <NUM> has a ground engaging propulsion structure comprising a first axle A<NUM> and a second axle A<NUM>, each axle being coupled to a pair of wheels (two wheels <NUM>, <NUM> are shown in <FIG> with one wheel <NUM> connected to the first axle A<NUM> and one wheel <NUM> connected to the second axle A<NUM>). The first axle A<NUM> may be a front axle and the second axle A<NUM> may be a rear axle. One or both of the axles A<NUM>, A<NUM> may be coupled to a motor M (see <FIG> discussed below) which is configured to drive movement of one or both pairs of wheels <NUM>, <NUM>. Thus, the wheels <NUM>, <NUM> may contact a ground surface and rotation of the wheels <NUM>, <NUM> may cause movement of the working machine <NUM> with respect to the ground surface. In other embodiments, the ground engaging propulsion structure may comprise tracks or rollers. In other embodiments, the drive transmission may not be operated by the motor M via a direct mechanical linkage, but instead the motor M may drive a hydraulic pump, which subsequently provides traction via one or more hydraulic motors that are drivingly connected to the wheels or tracks. Alternatively, the drive transmission may comprise an electric motor for providing traction to the wheels or tracks.

A load handling apparatus <NUM>, <NUM> is coupled to the machine body <NUM>. The load handling apparatus <NUM>, <NUM> may be mounted by a mount <NUM> to the machine body <NUM>. In an embodiment, the load handling apparatus <NUM>, <NUM> includes a working arm <NUM>, <NUM>.

The working arm <NUM>, <NUM> may be a telescopic arm having a first section <NUM> connected to the mount <NUM> and a second section <NUM> which is telescopically fitted to the first section <NUM>. In this embodiment, the second section <NUM> of the working arm <NUM>, <NUM> is telescopically moveable with respect to the first section <NUM> such that the working arm <NUM>, <NUM> can be extended and retracted. Movement of the first section <NUM> with respect to the second section <NUM> of the working arm <NUM>, <NUM> may be achieved by use of an extension actuator <NUM> which may be a double acting hydraulic linear actuator. One end of the extension actuator <NUM> is coupled to the first section <NUM> of the lifting arm <NUM>, <NUM> and another end of the extension actuator <NUM> is coupled to the second section <NUM> of the working arm <NUM>, <NUM> such that extension of the extension actuator <NUM> causes extension of the working arm <NUM>, <NUM> and retraction of the extension actuator <NUM> causes retraction of the working arm <NUM>, <NUM>. As will be appreciated, the working arm <NUM>, <NUM> may include a plurality of sections: for example, the working arm <NUM>, <NUM> may comprise two, three, four or more sections. Each arm section may be telescopically fitted to at least one other section.

The working arm <NUM>, <NUM> can be moved with respect to the machine body <NUM> and the movement is preferably, at least in part, rotational movement about the mount <NUM> (about pivot B of the working arm <NUM>, <NUM>). The rotational movement is about a substantially transverse axis of the machine <NUM>, the pivot B being transversely arranged.

Rotational movement of the working arm <NUM>, <NUM> with respect to the machine body <NUM> is, in an embodiment, achieved by use of at least one lifting actuator <NUM> coupled, at one end, to the first section <NUM> of the working arm <NUM>, <NUM> and, at a second end, to the machine body <NUM>. The lifting actuator <NUM> is a double acting hydraulic linear actuator, but may alternatively be single acting. In some embodiments, the lifting actuator is an electric linear actuator.

A load handling implement <NUM> may be located at a distal end of the working arm <NUM>, <NUM>. The load handling implement <NUM> may include a fork-type implement which may be rotatable with respect to the working arm <NUM>, <NUM> about a pivot D, this pivot also being transversely arranged. Other implements may be fitted such as shovels, grabs etc. Movement of the load handling implement <NUM> may be achieved by use of a double acting linear hydraulic actuator (not shown) coupled to the load handling implement <NUM> and the distal end of the section <NUM> of the working arm <NUM>, <NUM>.

In the illustrated embodiment, the operator structure <NUM> has a fixed angular orientation with respect to the front and/or rear axles A<NUM> and A<NUM>.

The working machine <NUM> includes an operator structure climate control assembly <NUM> for selectively adding and/or removing thermal energy to/from the operator structure <NUM> for selectively warming and/or cooling of the operator structure <NUM>, for example to preheat the operator structure <NUM>. The climate control assembly <NUM> is located in the operator structure <NUM>. The climate control assembly <NUM> includes an operator structure heat exchanger <NUM> configured to selectively add/remove thermal energy to/from the operator structure <NUM>. The heat exchanger <NUM> includes an operator structure cooler <NUM>, for example an air conditioning system, configured to selectively remove thermal energy from the operator structure <NUM>. The heat exchanger <NUM> includes an operator structure heater <NUM> configured to selectively add thermal energy to the operator structure.

The working machine <NUM> of <FIG> is provided with an outside heat exchanger assembly <NUM> that is mounted to the rear of the operator structure <NUM>, and is discussed in more detail below. In other embodiments, the outside heat exchanger assembly <NUM> may be mounted at other locations on the operator structure <NUM>, or at other locations on the working machine <NUM>.

With reference to <FIG>, the working machine <NUM> is an electric working machine having an electric energy storage unit <NUM> for providing electrical power to the working machine <NUM>. In this embodiment the electrical energy storage unit <NUM> comprises batteries, but in other embodiments may utilise capacitors or a combination of batteries and capacitors; or other storage technologies. In other embodiments the working machine <NUM> may be a "hybrid" working machine in which an internal combustion engine (ICE) and electric motors may both supply power to the ground engaging propulsion structure and/or the actuators to displace the working arm(s) <NUM>, <NUM>.

The working machine <NUM> includes an electric drive motor M coupled to the electric energy storage unit <NUM> via suitable control electrics (not shown) and configured to drive movement of one or both pairs of wheels <NUM>, <NUM>. The motor M is coupled to a driveshaft <NUM> to drive movement of the wheels <NUM>, <NUM> via axles A<NUM> and A<NUM>. The working machine <NUM> also includes a separate hydraulic pump electric motor <NUM> configured to drive a hydraulic pump <NUM> to move the working arms <NUM>, <NUM>, e.g. to actuate the actuators <NUM>, <NUM>. The hydraulic motor <NUM> is positioned proximal to the mount <NUM> of the load handling apparatus <NUM>, <NUM>. In other embodiments, a single motor may provide drive for traction and actuation of a working arm.

It is known that to increase the efficiency of operation of the working arm <NUM>, <NUM>, it is desirable for the hydraulic fluid <NUM> to be within an optimal temperature range that is typically above ambient temperature, e.g. a temperature range of <NUM>-<NUM>. At this temperature, the viscosity of the hydraulic fluid <NUM> is reduced and therefore frictional losses as it circulates within the hydraulic circuit <NUM> (see <FIG>) are reduced. Additionally, wear on the valves and other components within the circuit <NUM> may be reduced at this temperature. Temperatures above this range may however cause damage to components in the circuit <NUM>, e.g. due to improper lubrication, or sub-optimal performance, e.g. leakage from the breakdown of seals, and this is also undesirable.

When the working machine <NUM> has been inactive for a period of time (e.g. overnight) in most operating environments, the temperature will be below this desirable range and it will take a period of time for the fluid to reach this range (as a result of frictional effects as it circulates) dependent upon ambient temperatures and the intensity with which the machine is operated. In the intervening period, the operational efficiency of the machine is reduced. In some circumstances where the working arms are not operated intensively, the temperature may not achieve the desired range. The present inventors have therefore recognised the advantage of preheating the hydraulic fluid <NUM> to the desirable range to increase the efficiency of operation of the working machine <NUM>. Further, if the machine has been operating intensively for an extended period of time it is possible that the hydraulic fluid <NUM> exceeds the desirable temperature range, which may also be undesirable for the reasons stated above.

The present inventors have recognised that at the same time, there may be a demand for heat to be supplied to the operator structure <NUM> to improve operator comfort. The present inventors have recognised that the usage of electrical power supplied from the electrical energy storage unit <NUM> in such circumstances makes inefficient usage of this limited resource when a supply of thermal energy may already be available from the hydraulic fluid <NUM>.

The present inventors have also recognised that, in certain conditions, for example if the working machine <NUM> absorbs high levels of thermal energy (i.e. a solar load) from the sun, the operator structure <NUM> may exceed the desirable temperature range for optimal user comfort. At the same time, there may be a demand for heat to be supplied to the hydraulic fluid <NUM> in order to raise the hydraulic fluid temperature to within the optimal temperature range so as to improve the efficiency of the working machine <NUM>. The present inventors have recognised that the use of electrical power supplied by the storage unit <NUM> in such circumstances makes inefficient usage of this limited resource when a supply of thermal energy may already be available from the operator structure <NUM>.

In order to enable the preheating of the hydraulic fluid and/or the operator structure <NUM>, and the transfer of thermal energy between the hydraulic fluid and the operator structure <NUM>, the working machine <NUM> includes a thermal management system <NUM>. The thermal management system <NUM> is configured to connect a heat exchanger <NUM> arranged to selectively add and/or remove thermal energy from the hydraulic fluid circuit <NUM> to the operator structure <NUM> (i.e. via the operator structure climate control assembly <NUM>).

The thermal management system <NUM> is configured to determine a thermal energy requirement of the operator structure <NUM> based on a target operator structure temperature, and to determine a thermal energy requirement of the hydraulic fluid based on a target hydraulic fluid temperature. The thermal management system <NUM> includes an energy distribution system to selectively transfer thermal energy between the operator structure <NUM> and the hydraulic fluid <NUM>, based on the determined energy requirements thereof. It will be appreciated that the energy distribution system may be configured to selectively transfer thermal energy between the operator structure <NUM> and the hydraulic fluid <NUM> both during operation of the working machine <NUM> and whilst the working machine <NUM> is charging. This enables the thermal management system <NUM> to preheat the operator structure <NUM> and/or the hydraulic fluid <NUM> while the working machine <NUM> is charging, and to maintain optimal temperatures for the operator structure <NUM> and the hydraulic fluid <NUM> during operation of the working machine <NUM>.

Referring now to <FIG>, a thermal management system <NUM> of the working machine <NUM> is illustrated. The thermal management system <NUM> includes a hydraulic fluid heat exchanger <NUM>, for example a liquid/liquid heat exchanger. The hydraulic fluid heat exchanger <NUM> is located within a hydraulic fluid reservoir <NUM> so as to be immersed in the hydraulic fluid <NUM>. The energy distribution system of this embodiment features a coolant pump <NUM> for transferring a working fluid, e.g. a coolant such as ethylene-glycol, around a circuit <NUM> based on the state of a circuit switch <NUM>, i.e. a coolant switch <NUM>. The circuit <NUM> is in thermal communication with the hydraulic fluid heat exchanger <NUM> and to an operator structure heat exchanger <NUM>, that forms part of the cabin climate control assembly <NUM>. The operator structure heat exchanger <NUM> may be a liquid/gas heat exchanger.

The operator structure climate control assembly <NUM> includes a fan or a blower <NUM> that blows air over the operator structure heat exchanger <NUM> and into the operator structure <NUM>. A hydraulic fluid heater <NUM>, e.g. a heating element, is immersed within the hydraulic fluid <NUM> in the hydraulic fluid reservoir <NUM>. It will be appreciated that, the hydraulic fluid heater <NUM> may also in thermal communication with the circuit <NUM>. An outside, i.e. external, heat exchanger <NUM> is also in thermal communication with the circuit <NUM>.

<FIG> shows the hydraulic fluid circuit <NUM> in simplified form (e.g. without control valves etc.). The hydraulic fluid circuit <NUM> includes the hydraulic fluid reservoir <NUM>, supply flow path <NUM> to the hydraulic pump <NUM>. The hydraulic circuit <NUM> includes a machine load, which in this embodiment includes the extension actuator <NUM> and lift actuator <NUM>. In alternative arrangements, the machine load may include other devices in the circuit, and may include an auxiliary circuit to supply hydraulic fluid to an implement <NUM> mounted to the working arm <NUM>, <NUM>. Once the hydraulic fluid has been utilised by the component(s) of the working machine <NUM> it is returned to the reservoir <NUM> via the hydraulic flow path <NUM>. Energy transfer between the hydraulic fluid circuit <NUM> and the operator structure <NUM> is achieved using an energy transfer medium such as a water/glycol mixture pumped in a circuit between the hydraulic fluid circuit <NUM> and the operator structure <NUM>.

The thermal management system <NUM> enables coolant to be circulated by the energy distribution system around the circuit <NUM>, and is capable of drawing heat from the hydraulic fluid <NUM> in the reservoir <NUM> and supplying it to the operator structure <NUM> (via heat exchanger <NUM>) if there is a thermal energy surplus of the hydraulic fluid <NUM> and a thermal energy deficit of the operator structure <NUM>.

The thermal management system <NUM> enables coolant to be circulated by the energy distribution system around the circuit <NUM>, and is capable of drawing heat from the operator structure <NUM> and supplying it to the hydraulic fluid heat exchanger <NUM>, if there is a thermal energy surplus of the operator structure <NUM> and a thermal energy deficit of the operator structure <NUM>.

The circuit <NUM> includes a working fluid heater, i.e. a coolant heater, <NUM> to selectively heat the working fluid in the circuit <NUM>. The provision of the heater <NUM> enables the temperature of the working fluid to be increased, should external energy be required so as to heat the operator structure <NUM> and/or hydraulic fluid <NUM>.

The thermal management system <NUM> enables the hydraulic fluid to be kept within a desirable operating temperature range and also maintain the operator structure temperature at a desirable level for an operator. It will be appreciated that the thermal management system <NUM> is able to reject or discard excess thermal energy to the atmosphere, e.g. via the outside heat exchanger <NUM>.

It will be understood that the thermal management system <NUM> is configured to operate when the working machine <NUM> is in an 'active' state. Put another way, the thermal management system <NUM> is configured to operate when the working machine is either charging or in use (i.e. turned on).

Referring to <FIG>, the control logic for the thermal management system <NUM> of <FIG> is shown. The control logic controls the transfer of thermal energy between the hydraulic fluid <NUM> and the operator structure <NUM>, and enables preheating during charging of the working machine <NUM>, and efficient energy transfer during operation of the working machine <NUM>.

The working machine <NUM> includes a sensor (not shown) for measuring the temperature <NUM> of the operator structure <NUM>. The working machine <NUM> includes a sensor (not shown) for measuring the temperature <NUM> of the hydraulic fluid <NUM>. When the working machine is charging (but not turned on), the thermal management system <NUM> is configured to pre-heat the hydraulic fluid <NUM> and the operator structure <NUM> to their respective target temperatures <NUM>, <NUM>.

The thermal management system <NUM> has three charging states of operation to efficiently preheat the hydraulic fluid <NUM> and the operator structure <NUM>.

In a first charging state of operation <NUM> of the thermal management system <NUM>, the measured hydraulic fluid temperature <NUM> is less than the target hydraulic fluid temperature <NUM>, and there is a heating requirement of the hydraulic fluid <NUM>. In order to supply thermal energy to the hydraulic fluid <NUM>, the hydraulic fluid heater <NUM> and the coolant heater <NUM> are switched on and powered by the electric power charging the working machine <NUM>
The thermal management system <NUM> may be configured to prioritise pre-heating of the hydraulic fluid <NUM> to promote efficient operation. In some arrangements, the coolant pump <NUM> and coolant switch <NUM> of the energy distribution system may be switched off until the hydraulic fluid <NUM> has reached the target hydraulic fluid temperature <NUM>. In some arrangements, the fan <NUM> of the operator structure climate control assembly <NUM> may be switched off, this is because it might be assumed that the operator structure <NUM> is vacant when the working machine <NUM> is charging.

In a second charging state of operation <NUM> of the thermal management system <NUM>, the measured hydraulic fluid temperature <NUM> is at of close to the target hydraulic fluid temperature <NUM>. In said second charging state of operation <NUM>, if the measured operator structure temperature <NUM> is less than the target operator structure temperature <NUM>, there is a heating requirement.

The thermal management system <NUM> controls the operator structure climate control assembly in order to pre-heat the operator structure <NUM> to the target temperature of the operator structure <NUM>.

The thermal energy generated by the hydraulic fluid heater <NUM> and/or the coolant heater <NUM> may be used to pre-heat the operator structure <NUM>. The thermal management system <NUM> is able to determine the coolant pump speed and flow rate. The coolant switch <NUM> may be configured to direct coolant from the hydraulic fluid heat exchanger <NUM> to the operator structure heat exchanger <NUM> via the circuit <NUM> to transfer thermal energy from the hydraulic fluid heater <NUM> to the operator structure <NUM>. In some arrangements, the coolant may be heated directly via the coolant heater <NUM>.

In a third charging state <NUM> of the thermal management system <NUM>, the hydraulic fluid measured temperature <NUM> reaches and/or exceeds the hydraulic fluid target temperature <NUM>. In said third charging state <NUM>, the thermal management system <NUM> is configured to turn off the hydraulic fluid heater <NUM> and/or the coolant heater <NUM> to reduce the generation of unnecessary generation of thermal energy. The coolant pump <NUM> directs the flow of the coolant to the outside heat exchanger <NUM> to reject thermal energy to the atmosphere. The thermal management system <NUM> control logic implements feedback loops with the aim of preventing an excess of thermal energy being supplied to the hydraulic fluid, because this will decrease the efficiency of the working machine <NUM>.

During operation of the working machine <NUM>, the thermal management has three operational states to efficiently transfer thermal energy around the working machine <NUM>.

In a first operational state <NUM>, the measured hydraulic fluid temperature <NUM> is less than the target hydraulic fluid temperature <NUM>, and there is a heating requirement of the hydraulic fluid <NUM>. In said first operational state, the thermal energy of the hydraulic fluid <NUM> will increase as the hydraulic fluid <NUM> flows around the working machine <NUM>, e.g. to operate the working arm <NUM>, <NUM>. Due to this, externally supplied thermal energy, e.g. from the hydraulic fluid heater <NUM> and coolant heater <NUM>, may not be required and so may be turned off.

It will be appreciated that the thermal management system <NUM> may be configured to prioritise pre-heating of the hydraulic fluid <NUM> to promote efficient operation thereof. This may mean that the coolant pump and coolant switch <NUM> are switched off until the hydraulic fluid <NUM> has reached the target hydraulic fluid temperature <NUM>.

In a second operational state <NUM>, the measured hydraulic fluid temperature <NUM> has reached the target hydraulic fluid temperature <NUM>, and the measured operator structure temperature <NUM> is less than the target operator structure temperature <NUM>, there is a heating requirement of the operator structure <NUM>.

During operation of the working machine <NUM>, it will be understood that thermal energy will continuously be generated in the hydraulic fluid <NUM>. The excess thermal energy generated may be used to heat the operator structure. In such arrangements, the hydraulic fluid heater and the coolant heater <NUM> can be switched off. The thermal management system directs the flow of coolant from the hydraulic fluid heat exchanger <NUM> to the operator structure heat exchanger <NUM> via the circuit <NUM> to transfer thermal energy from the hydraulic fluid <NUM> to the operator structure <NUM>.

In a third operational state <NUM>, the measured temperature of the operator structure <NUM> has reached the target temperature <NUM>, there is a cooling requirement of the hydraulic fluid <NUM> due to thermal energy generated therein by operation of the working machine <NUM>.

In order to remove thermal energy from the hydraulic fluid <NUM>, the thermal management system <NUM> activates the coolant pump <NUM> and the coolant switch <NUM>. Flow of coolant is directed to the outside heat exchanger <NUM> and reject thermal energy from the coolant to the atmosphere.

It will be appreciated that in the first, second a third operational states <NUM>, <NUM>, <NUM> require sufficient thermal energy to be generated within the hydraulic fluid during operation of the working machine so as to heat both the hydraulic fluid <NUM> and the operator structure <NUM>. However, if this is not the case, e.g. if the working machine <NUM> is not being operated at maximum capacity, the thermal management system is configured to supply additional thermal energy, e.g. from the coolant heater <NUM>, to heat the hydraulic fluid <NUM> and the operator structure <NUM>.

The thermal management system <NUM> may be further configured to transfer thermal energy from the operator structure <NUM> to the hydraulic fluid <NUM>, although this is not illustrated in <FIG>. The coolant pump <NUM> pumps coolant around the circuit <NUM> and the coolant switch directs the flow of coolant from the operator structure heat exchanger <NUM> to the to the hydraulic fluid heat exchanger <NUM> to supply thermal energy to the hydraulic fluid <NUM>. The thermal management system <NUM> may also be configured to transfer thermal energy from the atmosphere to the operator structure <NUM> and/or the hydraulic fluid <NUM>.

It will be understood that the thermal management system <NUM> the thermal management system <NUM> is activated when the state of charge of the working machine <NUM> reaches a predetermined threshold <NUM>. Typically, the predetermined threshold <NUM> of charge of the working machine <NUM> is approximately <NUM>%, but any suitable charge state may be used. When the charge state of the working machine <NUM> reaches this predetermined threshold, the thermal management system <NUM> pre-heats the operator structure <NUM> and hydraulic fluid <NUM> to pre-determined target temperatures <NUM>, <NUM>.

The thermal management system <NUM> may be configured to preheat the operator structure <NUM> and hydraulic fluid <NUM> to their target temperatures for an expected time (i.e. an expected start time) of operation <NUM> of the working machine <NUM>. This preheat logic process is illustrated in <FIG>. In some arrangements, this expected time of operation (or 'Get Active Time') <NUM> may be inputted manually by an operator (via a start manual control function). In alternative arrangements, this expected time of operation <NUM> may be determined based on historic operation start times <NUM>. Once the current time <NUM> equals the expected time of operation <NUM> minus the time required to heat up the operator structure and hydraulic fluid <NUM> (the warm up time), the thermal management system <NUM> will begin preheating.

The preheat control logic of <FIG> is, in this embodiment, processed by the thermal management system <NUM> of the working machine <NUM>. However, it shall be appreciated that in alternative embodiments, the control logic could be carried out remotely with the output of the preheat logic transmitted (e.g. wirelessly) and inputted into the thermal management system <NUM>.

The thermal management system <NUM> of this embodiment is particularly advantageous for use in compact working machines with spatial limitations e.g. mini excavators which cannot accommodate bulky and heavy equipment.

Referring now to <FIG>, an alternative thermal management system <NUM> of the working machine <NUM> is illustrated schematically.

The thermal management system <NUM> includes a cooling circuit <NUM> and a heating circuit <NUM>. A heat transfer fluid or coolant such as water-ethylene-glycol mix may be used in both the heating and cooling circuits <NUM>, <NUM>. Both the heating and cooling circuits <NUM>, <NUM> use coolant pumps 56a, 56b to circulate the coolant around the circuit. The thermal management system <NUM> is configured to control the flow rate and distribution of the heat transfer fluid depending on the rate and direction of heat transfer required from the energy requirement of the working machine <NUM> and the local energy requirements of the hydraulic fluid <NUM> and the operator structure <NUM>.

The cooling circuit <NUM> is selectively connected to the operator structure cooler <NUM> via a flow control valve <NUM>. The cooling circuit <NUM> is also connected to an outside heat exchanger <NUM> by first and second three way flow control valve arrangements 84a and 84b. Finally, the cooling circuit <NUM> is connected to the hydraulic fluid heat exchanger <NUM> via two further three way flow control valve arrangements 86a and 86b. The third port of the three way flow control valve arrangements 84a, 84b, 86a and 86b are connected to the heating circuit <NUM> such that the three way flow control valve arrangements can switch to the flow of either the cooling circuit <NUM> or heating circuit <NUM> as is required.

The heating circuit <NUM> is also selectively connected to the operator structure heater <NUM> via a further flow control valve <NUM>. The operator structure cooler <NUM> and heater <NUM> are both, in this embodiment, provided as part of an operator structure climate control assembly <NUM> that also includes a fan <NUM> that blows outside air past both the operator structure cooler <NUM> and operator structure heater <NUM> and into the operator structure <NUM> via suitable vents in order to provide for operator structure <NUM> heating or cooling as required. The operator structure climate control assembly <NUM> also allows air within the operator structure <NUM> to be recirculated through the operator structure cooler <NUM> or heater <NUM> in certain embodiments.

The energy distribution system of this embodiment features a heat pump circuit. The heat pump circuit includes a vapour compression refrigerant circuit to facilitate the transfer of thermal energy between the heating circuit and cooling circuit <NUM>, <NUM>. The refrigerant circuit comprises a compressor <NUM> in series with a condenser <NUM>, an expansion device <NUM> and an evaporator <NUM>. The cooling circuit <NUM> is connected to the evaporator <NUM> and the heating circuit <NUM> is connected to the condenser <NUM> such that thermal energy may be transferred from the cooling circuit <NUM> to the heating circuit <NUM> via the refrigerant circuit <NUM>. The refrigerant circuit <NUM> is a closed loop and contains a suitable refrigerant such as R134a or R1234yf.

The work done by the refrigerant compressor <NUM> of the energy distribution system on the refrigerant increases the enthalpy (i.e. the energy content) of the refrigerant and enables thermal energy to be transferred from a location of lower temperature to a location of higher temperature. This is particularly advantageous for this application because it is possible that when heat transfer occurs from the operator structure <NUM> to the hydraulic fluid <NUM>, the hydraulic fluid <NUM> will already be at a higher temperature than the operator structure. Without the refrigerant compressor, heat transfer in this case would occur from the hydraulic fluid <NUM> to the operator structure even though the heating requirement for the optimal performance of the working machine <NUM> is in the opposite direction.

The thermal management system <NUM> comprises a hydraulic fluid heat exchanger <NUM> located within the hydraulic fluid reservoir <NUM> to be immersed within the hydraulic fluid <NUM>, for example a liquid/liquid heat exchanger. The hydraulic fluid heat exchanger <NUM> is connected to a circuit <NUM> of the thermal management system <NUM> that is filled with a suitable working liquid such as ethylene-glycol and that is circulated by means of a coolant pump 56a, 56b to the operator structure heat exchanger <NUM>, for example a liquid/gas heat exchanger, that forms part of the operator structure climate control assembly <NUM>. The circuit <NUM> then returns the coolant to the hydraulic fluid heat exchanger <NUM>. It will be appreciated that the transfer of thermal energy from the hydraulic fluid reservoir <NUM> to the hydraulic fluid heat exchanger <NUM> may take place by free convection due to the difference in temperature gradients. Alternatively, there may be an external source, for example a pump or a fan, to promote forced convection.

In some embodiments, a heating element is also immersed within the hydraulic fluid <NUM> in the hydraulic fluid reservoir <NUM>. Both the coolant pumps 56a, 56b and the heating element are, in this embodiment, electrically powered. Electrical power may be provided either to or from an external power source e.g. mains electrical power via a charger (not shown) or from the electrical energy storage unit <NUM>.

In order to raise the temperature of the hydraulic fluid <NUM> to the desirable operating range after an extended period where the working machine <NUM> is inoperative, the heating element may be used to preheat the hydraulic fluid <NUM>. Whilst the heating element is electrically powered, such preheating may occur whilst the working machine <NUM> is placed onto charge overnight. This means that the electrical power is not supplied from the electrical energy storage unit <NUM> on the working machine <NUM>, which would otherwise reduce the electrical energy available to the working machine <NUM> for performing working operations.

In addition, if the hydraulic fluid <NUM> is preheated at the very start of operation of the working machine <NUM>, this means that the thermal energy of the hydraulic fluid <NUM> can be used to supply heat to the operator structure <NUM> straight away, or at least with a much reduced delay. Indeed, if low outside air temperatures are anticipated for a particular working day, the heating element may be controlled in such a way as to heat the hydraulic fluid to a higher temperature than may otherwise be required in anticipation of some of said heat being supplied to the operator structure climate control assembly <NUM> immediately upon vehicle operation or to preheat the operator structure <NUM> before the operator enters it.

In order to ensure that thermal energy can be transferred both from the hydraulic fluid <NUM> to the operator structure <NUM> and from the operator structure <NUM> to the hydraulic fluid, the heat exchangers of the embodiment of <FIG> are configured to selectively switch between the heating circuit <NUM> and the cooling circuit <NUM>. The cooling circuit <NUM> is connected to the evaporator <NUM> and the heating circuit <NUM> is connected to the condenser <NUM> such that thermal energy may be transferred from the cooling circuit <NUM> to the heating circuit <NUM> via the refrigerant circuit <NUM>.

In <FIG>, the flow of heated coolant in the heating circuit <NUM> is denoted by a thick solid line whereas an inoperative part of the heating circuit <NUM> is denoted by dotted lines. The flow of coolant in the cooling circuit <NUM> is denoted by a solid thin line, whereas inoperative parts of the coolant circuit are also denoted by broken lines.

In <FIG>, the thermal management system <NUM> is operating with thermal energy being absorbed by the refrigerant circuit <NUM> via the following heat transfer process: thermal energy in the hydraulic fluid flowing in the hydraulic flowing circuit <NUM> is transferred to the cooling circuit <NUM> via the hydraulic fluid heat exchanger <NUM> and from ambient air via the outside heat exchanger <NUM>. This thermal energy is then transferred from the cooling circuit <NUM> to the refrigerant circuit <NUM> via the evaporator <NUM> and the refrigerant circuit <NUM> then transfers this heat to the operator structure heater <NUM> via the condenser <NUM> and the heating circuit <NUM>. The fan <NUM> blows outside air over the operator structure heater <NUM> to raise the temperature within the operator structure <NUM>. It can be seen that the flow control valve <NUM> is closed so that the operator structure cooler <NUM> is inoperative.

In order to maintain the desired viscosity of the hydraulic fluid, the rate of coolant flow through the hydraulic fluid heat exchanger <NUM> is metered to control the rate of heat rejection from the hydraulic fluid, with any shortfall in the heat required to be transferred to the operator structure heater <NUM> being supplied by the outside heat exchanger <NUM>.

<FIG> illustrates the thermal management system <NUM> operating in a different mode which reflects a situation in which the working machine <NUM> is operating in a high ambient temperature and the hydraulic fluid and the operator structure <NUM> simultaneously require cooling. Accordingly, in this situation thermal energy is absorbed by the refrigerant circuit <NUM> via the transfer of thermal energy from the hydraulic fluid in the hydraulic fluid circuit <NUM> to the refrigerant circuit <NUM> via the cooling circuit <NUM> and evaporator <NUM>. Simultaneously, thermal energy is also transferred from the operator structure <NUM> to the evaporator <NUM> via the operator structure cooler <NUM>. This thermal energy is then rejected to the outside air from the refrigerant circuit <NUM> via the condenser <NUM> and outside heat exchanger <NUM>, as the three way flow control valve arrangements 84a and 84b are now switched to allow flow of coolant in the heating circuit <NUM> through the outside heat exchanger <NUM>. Again, the temperature of the hydraulic fluid is maintained within its target temperature range by metering the rate of coolant flow through the hydraulic fluid heat exchanger <NUM>.

Referring to <FIG>, the thermal management system <NUM> is operating in a mode to reflect a situation where, for example, a pre conditioning of the hydraulic fluid and operator structure <NUM> air temperature is required before operation of the working machine <NUM>, or the working machine <NUM> has just started operating from a cold start and the operator requires the operator structure <NUM> to be heated and at the same time the hydraulic fluid in the hydraulic circuit <NUM> is lower than the target temperature range. Consequently, thermal energy is absorbed by the refrigerant circuit <NUM> via a heat transfer process that takes thermal energy from the outside air to the cooling circuit <NUM> via the outside heat exchanger <NUM> and then into the refrigerant circuit <NUM> via the evaporator <NUM>.

Alternatively, if there is not enough thermal energy available from the atmosphere to meet the energy requirement of the working machine <NUM>, the thermal management system <NUM> may absorb thermal energy from any suitable source, for example, from the electric heater, the fuel burning heater, the electric storage device <NUM> or the electric motor <NUM>.

This thermal energy is then transferred to the hydraulic fluid in the hydraulic fluid circuit <NUM> and to the operator structure <NUM> via the refrigerant circuit <NUM> to the condenser <NUM> and then into the heating circuit <NUM> which has its flow control valves set to allow the flow of heated coolant into both the operator structure heat exchanger <NUM> and the hydraulic fluid heat exchanger <NUM>.

With reference to <FIG> the thermal management system <NUM> is set to reflect a situation where the ambient temperature is relatively warm and the operator has requested cooling within the operator structure <NUM> and simultaneously the machine <NUM> is operating on a light duty cycle such that the natural frictional losses due to flow of hydraulic fluid around the hydraulic fluid circuit <NUM> is not capable of maintaining the temperature of the hydraulic fluid at the desirable temperature range and therefore some heating of the hydraulic fluid is also required.

Accordingly, thermal energy is absorbed by the refrigerant circuit <NUM> via the operator structure air to the cooling circuit <NUM> via the operator structure cooler <NUM> and to the refrigerant circuit <NUM> via the cooling circuit <NUM> and evaporator <NUM>. This thermal energy is then rejected to the hydraulic fluid and to the outside air by way of its transfer to the condenser <NUM> via the refrigerant circuit <NUM> and from the condenser <NUM> to the heating circuit <NUM> and then into both the hydraulic fluid heat exchanger <NUM> and the outside heat exchanger <NUM>. The rate of flow of heated coolant into the hydraulic fluid heat exchanger may be metered to ensure the temperature of the hydraulic fluid is maintained within the target temperature range, with the remaining flow and excess thermal energy being expelled to the outside air via the outside heat exchanger <NUM>.

It can therefore be appreciated that the thermal management system <NUM> may be switched via the opening and closing of the flow control valves to efficiently provide and remove thermal energy to the operator structure <NUM> and or the hydraulic fluid circuit <NUM> as required and to remove thermal energy from the operator structure <NUM> and the hydraulic fluid circuit <NUM> as required, thereby ensuring a pleasant environment for the working machine operator and the hydraulic fluid being utilised within the desirable temperature range for efficient movement of the working arm <NUM>, <NUM>.

The thermal management system <NUM> may also be adapted to supply or remove thermal energy to the batteries and power electronics by adding the suitable further valves and heat exchangers to the system of <FIG>. It will be appreciated that the thermal management system <NUM> may be adapted to supply or remove thermal energy to any other machine device requiring active thermal management to function or to improve thermal efficiency of performance by adding suitable additional valves and heat exchangers to the system of <FIG>.

Referring to <FIG>, the control logic of the thermal management system <NUM> is illustrated. This process is configured to selectively transfer thermal energy between the hydraulic fluid <NUM> and the operator structure <NUM> for preheating and for efficient energy transfer during operation of the working machine <NUM>.

In order to establish whether there is a heating or cooling requirement of the hydraulic fluid <NUM>, the thermal management system <NUM> carries out a hydraulic fluid energy requirement calculation <NUM>. This calculation <NUM> determines a hydraulic fluid energy requirement <NUM> based on a target hydraulic fluid temperature <NUM>. The target hydraulic fluid temperature <NUM> can be manually inputted into the thermal management system <NUM> or can be pre-set into the thermal management system <NUM>. The target hydraulic fluid temperature <NUM> may be inputted as a temperature range with an upper and lower temperature limit. This target hydraulic fluid temperature <NUM> may be in the range of <NUM> to <NUM>, although it will be appreciated that the target temperature may be varied to suit to the working machine <NUM> and/or the application.

It will be appreciated that, if there is a need to preheat the operator structure <NUM> to achieve a target operator structure temperature <NUM>, this thermal energy may be supplied by the hydraulic fluid. A target hydraulic fluid temperature <NUM> may be set below the measured hydraulic fluid temperature <NUM>, and that this target hydraulic fluid temperature <NUM> may be below the temperature range for optimal working efficiency of the hydraulic fluid. This enables the thermal management system <NUM> to transfer thermal energy from the hydraulic fluid to the operator structure <NUM>. Thermal energy may then be supplied to the hydraulic fluid from an alternative source.

The working machine <NUM> may include a device (not shown) for measuring the flow rate of the hydraulic fluid <NUM> along the hydraulic fluid flow path. The device may be, for example, a flow meter. The determination of the energy requirement <NUM> of the hydraulic fluid <NUM> may incorporate the measured hydraulic fluid flow rate <NUM>. This has been found to increase the accuracy of the energy requirement <NUM> of the hydraulic fluid <NUM>. The determination of the energy requirement <NUM> of the hydraulic fluid <NUM> may incorporate the volume of hydraulic fluid and/or the specific heat capacity of the hydraulic fluid <NUM>. Monitoring of one or more of these factors enables the amount of energy required to heat the hydraulic fluid to a pre-determined temperature and/or the surplus energy contained within the hydraulic fluid.

If the hydraulic fluid energy requirement <NUM> is less than zero (i.e. if the energy requirement is negative), there is an energy surplus of the hydraulic fluid and the thermal management system <NUM> will selectively remove thermal energy from the hydraulic fluid <NUM> via the hydraulic fluid heat exchanger <NUM>. Put another way, if the measured temperature <NUM> of the hydraulic fluid is greater than the target hydraulic fluid temperature <NUM>, there is an energy surplus of the hydraulic fluid, and the thermal management system <NUM> will selectively remove thermal energy from the hydraulic fluid <NUM> via the hydraulic fluid heat exchanger <NUM>.

If the hydraulic fluid energy requirement <NUM> is more than zero (i.e. if the energy requirement is positive), there is an energy deficit of the hydraulic fluid and the thermal management system <NUM> will selectively input thermal energy into the hydraulic fluid <NUM> via the hydraulic fluid heat exchanger <NUM>. Put another way, if the measured temperature <NUM> of the hydraulic fluid is less than the target hydraulic fluid temperature <NUM>, there is an energy deficit of the hydraulic fluid and the thermal management system <NUM> will selectively add thermal energy to the hydraulic fluid <NUM> via the hydraulic fluid heat exchanger <NUM>.

In order to establish whether there is a heating or cooling requirement of the operator structure <NUM>, the thermal management system <NUM> carries out an operator structure energy requirement calculation <NUM>. This calculation <NUM> determines an operator structure energy requirement <NUM> based on the target operator structure temperature <NUM>. The target operator structure temperature <NUM> can be manually inputted into the thermal management system <NUM> or can be pre-set into the thermal management system <NUM>.

The working machine <NUM> may include a sensor (not shown) for measuring an ambient temperature <NUM> surrounding the working machine <NUM>. The working machine <NUM> may include a sensor (not shown) for measuring the solar load <NUM> on the operator structure <NUM>. The determination of the energy requirement <NUM> of the operator structure <NUM> may further include the measured ambient temperature <NUM> and/or the measured solar load <NUM>. This has been found to increase the accuracy of the energy requirement <NUM> of the operator structure <NUM>.

If the operator structure energy requirement <NUM> is less than zero (i.e. the energy requirement is negative), there is an energy surplus of the operator structure <NUM> and the thermal management system <NUM> will selectively remove thermal energy from the operator structure <NUM> via the climate control assembly <NUM>. Put another way, if the measured temperature <NUM> of the operator structure <NUM> is greater than the target operator structure <NUM>, there is an energy surplus of the operator structure <NUM> and the thermal management system <NUM> will selectively remove thermal energy from the operator structure <NUM> via the climate control assembly <NUM>.

If the operator structure energy requirement <NUM> is more than zero (i.e. if the energy requirement is positive), there is an energy deficit of the operator structure <NUM> and the thermal management system <NUM> will selectively input thermal energy into the operator structure <NUM> via the climate control assembly <NUM>. Put another way, if the measured temperature <NUM> of the operator structure <NUM> is less than the target operator structure temperature <NUM>, there is an energy deficit of the operator structure <NUM> and the thermal management system <NUM> will selectively add thermal energy from the operator structure <NUM> via the climate control assembly <NUM>.

If the thermal management system <NUM> determines that there is an operator structure energy surplus and a hydraulic fluid energy deficit, the thermal management system <NUM> is configured to selectively transfer thermal energy from the operator structure <NUM> to the hydraulic fluid <NUM>. Alternatively, if the thermal management system <NUM> determines that there is an operator structure energy deficit and a hydraulic fluid energy surplus, the thermal management system is configured to transfer thermal energy from the hydraulic fluid <NUM> to the operator structure <NUM>.

The thermal management system <NUM> is configured to perform an energy balance calculation <NUM> in order to determine the energy requirement <NUM> of the working machine <NUM>. The energy balance calculation <NUM> is based on the energy requirement <NUM> of the hydraulic fluid <NUM>, the energy requirement <NUM> of the operator structure <NUM> and the work done by components of the energy distribution system.

As has been discussed above, the working machine <NUM> includes an energy distribution system to selectively transfer thermal energy between the operator structure <NUM> and the hydraulic fluid <NUM>. As has been discussed above, in some embodiments, the energy distribution system <NUM> may incorporate a means of energy transfer which, when operated, results in additional energy being added to the energy distribution system. An example of this may be in the form of a vapour compression refrigerant circuit (as is discussed with reference to <FIG> below). The work carried out on refrigerant within the refrigerant circuit by the compressor <NUM> further increases the energy content of said refrigerant, and the determination of the energy requirement <NUM> of the working machine <NUM> may incorporate the energy inputted by the energy distribution system itself. Incorporation of the energy inputted by the energy distribution system of <FIG> into the energy requirement <NUM> of the working machine <NUM> has been found to improve the accuracy of the energy balance calculation <NUM>.

If the value energy requirement <NUM> of the working machine <NUM> is less than zero (i.e. where the energy requirement <NUM> is negative), there is a surplus of energy of the working machine <NUM>. For example, if both the operator structure <NUM> and the hydraulic fluid <NUM> have temperatures above their respective temperatures and so each have an energy surplus, or if an energy deficit of either the operator structure <NUM> or hydraulic fluid <NUM> is smaller than the energy surplus of the other added to the energy inputted into the energy distribution system by the refrigerant compressor <NUM>. Where it is determined that the working machine <NUM> has an energy surplus, the thermal management system <NUM> is configured to selectively remove thermal energy from the working machine <NUM> (e.g. from the operator structure <NUM> and/or the hydraulic fluid).

If the energy requirement <NUM> of the working machine <NUM> is more than zero (i.e. where the energy requirement <NUM> is positive), there is an energy deficit of the working machine <NUM>.

For example, if both the operator structure <NUM> and the hydraulic fluid <NUM> have temperatures below their respective target temperatures and so each have an energy deficit that is greater than any energy inputted into the energy distribution system by the refrigerant compressor <NUM>, or if an energy deficit of either the operator structure <NUM> or hydraulic fluid <NUM> is greater than the energy surplus of the other added to the energy inputted into the energy distribution system by the refrigerant compressor <NUM>. Where it is determined that the working machine <NUM> has an energy deficit the thermal management system <NUM> is configured to selectively input thermal energy into the operator structure <NUM> and/or the hydraulic fluid.

Determining the energy requirements of the operator structure <NUM>, hydraulic fluid <NUM> and the energy inputted into the energy distribution system as a part of the calculation of the energy requirement <NUM> of the working machine <NUM> enables the thermal management system <NUM> to determine the local energy requirements as well as for the overall working machine <NUM>. This, in turn, enables the thermal management system <NUM> to selectively remove thermal energy from a first location/component having an energy surplus, and to supply said surplus energy to a second location/component having an energy deficit. This arrangement has been found to increase the efficiency of the thermal management system <NUM>, by facilitating heat transfer around the working machine <NUM> prior to thermal energy being added/removed from the working machine <NUM>. The thermal management system <NUM> may be configured to prioritise the removal/inputting of thermal energy to systems of the working machine <NUM> which need protection from overheating/cooling to a damaging level.

In order to further aid the removal of thermal energy from the hydraulic fluid <NUM> in the event of an energy surplus, the thermal management system <NUM> may further comprise a hydraulic fluid in-line cooler and/or an electric fan. Additionally, the thermal management system <NUM> may employ system de-rate, where the working machine <NUM> is operated at less than its rated maximum capability, to slow down the generation of thermal energy.

The working machine <NUM> includes an electric heater (not shown) for supplying thermal energy to the thermal management system <NUM>. If the working machine <NUM> is in an active state, electric power is supplied to the electric heater from mains electricity (if the working machine is charging) or from the electric storage unit <NUM> (if the working machine is turned on). The addition of an electric heater enables a quick supply of thermal energy if there is none readily available from an alternative heat source, as discussed in more detail below.

The thermal energy inputted into the working machine <NUM> by the thermal management system <NUM> may be absorbed from any suitable source of thermal energy, for example, from the electric heater, a fuel burning heater the electric storage device <NUM> or the electric motor <NUM>. Through the determination of the energy requirement <NUM> of the working machine <NUM>, the thermal management system <NUM> is able to determine the amount of thermal energy that needs to be absorbed from the alternative energy sources for the heating of the operator structure <NUM> and/or the hydraulic fluid <NUM>.

As is discussed above, the working machine <NUM> includes an outside heat exchanger assembly <NUM>. The outside heat exchanger assembly <NUM> includes an outside heat exchanger <NUM>. In some embodiments, the outside heat exchanger <NUM> is a radiator. The outside heat exchanger <NUM> is configured to liberate thermal energy from the atmosphere and to supply thermal energy to the thermal management system if there is an energy deficit of the thermal management system <NUM>. Additionally, in the case of an energy surplus, the outside heat exchanger <NUM> is configured to reject surplus thermal energy from the thermal management system <NUM> to the atmosphere.

Where it is determined that the working machine <NUM> has an energy surplus, the thermal management system <NUM> is configured to selectively reject thermal energy from the working machine <NUM> to the atmosphere. Where it is determined that the working machine <NUM> has an energy deficit, the thermal management system <NUM> is configured to selectively absorb thermal energy from the atmosphere. It will be appreciated that the thermal management system <NUM> may be configured to absorb/receive energy from several heat sources, for example other components of the working machine <NUM> such as the electric heater, the electric storage device <NUM>, the hydraulic pump electric motor <NUM>, electric motor M for providing, at least in part, tractive power to the working machine <NUM> or any suitable component of the working machine <NUM>.

Alternatively, the thermal management system <NUM> may be configured to reject thermal energy to several heat sinks, for example other components of the working machine <NUM> such as the electric storage device <NUM>, the hydraulic pump electric motor <NUM>, electric motor M for providing, at least in part, tractive power to the working machine <NUM> or any suitable component of the working machine <NUM>. The thermal management <NUM> may be configured to include the amount of thermal energy rejected to/absorbed from these alternative heat sinks/sources in the energy balance calculation <NUM>. This may improve the accuracy of the machine energy requirement <NUM> and help to inhibit the inefficient rejection/absorption of thermal energy.

Claim 1:
An electric working machine (<NUM>) comprising:
an electric energy storage unit (<NUM>) configured to provide electrical power to the working machine (<NUM>);
a hydraulic fluid circuit (<NUM>) arranged to provide hydraulic fluid (<NUM>) to one or more hydraulic actuators to perform a working operation;
an operator structure (<NUM>);
an operator structure climate control assembly (<NUM>) arranged to selectively add and/or remove thermal energy to/from the operator structure (<NUM>) for selectively warming and cooling the operator structure (<NUM>);
a heat exchanger (<NUM>) arranged to selectively add and/or remove thermal energy from the hydraulic fluid circuit (<NUM>) for selectively warming and cooling the hydraulic fluid (<NUM>); and
a thermal management system (<NUM>) connecting the heat exchanger (<NUM>) to the operator structure climate control assembly (<NUM>),
wherein the thermal management system (<NUM>) is configured to determine an operator structure energy requirement (<NUM>) based on a target operator structure temperature (<NUM>) and a hydraulic fluid energy requirement (<NUM>) based on a target hydraulic fluid temperature (<NUM>), and
wherein the thermal management system (<NUM>) comprises an energy distribution system to selectively transfer thermal energy between the operator structure (<NUM>) and the hydraulic fluid (<NUM>) based on the relative values of the operator structure energy requirement (<NUM>) and the hydraulic fluid energy requirement (<NUM>); and
wherein the thermal management system (<NUM>) is configured to heat the hydraulic fluid (<NUM>) and/or operator structure (<NUM>) to the respective target temperature(s) (<NUM>, <NUM>) prior to or at an expected time of operation (<NUM>) of the working machine (<NUM>).