System for heating a catalytic converter

Abstract

A system 102 for heating a catalytic converter 110 of a vehicle 100 comprises a heater 118 for heating the catalytic converter, and a photovoltaic module 116 mounted to the vehicle. The photovoltaic m

Description

TECHNICAL FIELD The present invention relates to a system for heating a catalytic converter of a vehicle. Aspects of the invention relate to a system, to a control system, to a vehicle, and to a method of energy management. BACKGROUND TO THE INVENTION Catalytic converters are widely used in the automotive industry to reduce pollution emissions from an internal combustion engine. More specifically, catalytic converters are widely used in vehicle exhaust systems to catalyse a redox reaction of the exhaust gases, converting toxic gases and pollutants contained in the exhaust gas into less-harmful forms. However, catalytic converters are typically ineffective below a minimum activation temperature and require a warm-up period, following engine start-up, before they can effectively catalyse the redox reaction. For example, a typical warm-up period may last approximately 2 to 3 minutes before the catalytic converters reach their minimum activation temperature. As a result, high levels of polluting emissions are observed immediately following engine start-up (whilst the catalytic converter is still cold). This issue is particularly problematic in relation to short journeys, and urban driving scenarios, where a cold start is most frequently encountered. It is against this background that the present invention has been devised. SUMMARY OF THE INVENTION According to an aspect of the invention, there is provided a system for heating a catalytic converter of a vehicle. The system comprises: a heater for heating the catalytic converter; and a photovoltaic module for mounting to the vehicle. The photovoltaic module is electrically connected to the heater and configured to convert sunlight into electrical power for powering the heater to heat the catalytic converter. In this manner, the heater is supplied with electrical power whenever the photovoltaic module is exposed to sufficient light, and the catalytic converter is therefore heated even while the vehicle is shut-down, or in a key-off state. The temperature of the catalytic converter is therefore elevated without consuming other energy resources and prepared for efficient operation when the engine is subsequently activated. The warm-up period is therefore significantly reduced or eliminated, mitigating unwanted emissions following engine start-up. The photovoltaic module may, for example, be mountable to a roof or exterior area of the vehicle and the heater may be coupled to an exhaust system of the vehicle for heating the catalytic converter. In an example, the system is electrically connectable to one or more electric vehicle systems for energy management of the heater and the photovoltaic module. For example, the one or more electric vehicle systems may comprise: an electric drive system, and / or an auxiliary system for auxiliary equipment of the vehicle. In this manner, electrical circuitry may connect the heater, the photovoltaic module and the one or more electrical vehicle systems together to allow for energy distribution therebetween. Each electric vehicle system may, for example, include a respective battery energy storage system for electrical connection to the photovoltaic module and the heater. In this manner, the battery energy storage system can act as an energy buffer, storing excess electrical power and / or supplementing a power shortfall. In an example, the one or more electric vehicle systems may include the electric drive system and the auxiliary system. The electric drive system may, for example, include a high voltage battery energy storage system and the auxiliary system may include a low voltage battery energy storage system. In an example, the system may further comprise a controller or a control system configured to control the electrical power supply between the photovoltaic module, the heater and the one or more electric vehicle systems. In an example, the system may further comprise or connect to one or more vehicle activation sensors configured to generate a signal indicative of an activation state of the vehicle. For example, the one or more vehicle activation sensors may be configured to monitor a startup system and / or ignition system of the vehicle. The control system may include one or more controllers configured to execute machine readable instructions to: receive the signal from the one or more vehicle activation sensors; determine the activation state of the vehicle as one of a plurality of vehicle activation states based on the received signal; and control the electrical power supply between the photovoltaic module, the heater and the one or more electric vehicle system based on the determined activation state of the vehicle. In this manner, the power supply can be adapted according to the needs or priorities of the vehicle in different activation states. Optionally, the plurality of activation states may include a key-off state of the vehicle, also known as a shut-down state (when the vehicle is not in use). The control system may be configured to supply electrical power from the photovoltaic module to the heating element when the control system determines the key-off state of the vehicle. In the key-off state, the heater may therefore passively heat the catalytic converter ready for later use. In an example, the control system may be configured to supply a surplus of electrical power, exceeding a power demand of the heater, from the photovoltaic module to the battery energy storage system of at least one of the one or more electric vehicle systems when the control system determines the key-off state of the vehicle. For example, the control system may be configured to supply the surplus of electrical power to the high voltage battery energy storage system of the electric drive system. Optionally, the plurality of activation states includes an engine-active state of the vehicle, i.e. a state following engine startup during which the engine is combusting fuel. The control system may be configured to supply electrical power from the photovoltaic module to the one or more electric vehicle systems when the control system determines the engineactive state. For example, the control system may be configured to supply electrical power from the photovoltaic module to the low voltage battery energy storage system of the auxiliary system when the control system determines the engine-active state. In the engine active state, the fuel combustion heats the catalytic converter and thus the usefulness of supplying power to the heater may be reduced. The control system may therefore be configured to reduce the supply of electrical power from the photovoltaic module to the heater between determining the key-off state and the engine-active state. In an example, the control system may be configured to supply a shortfall of electrical power, required to meet a power demand of the heater, from the photovoltaic module to the heater when the control system determines the engine-active state. Optionally, the plurality of vehicle activation states may include a key-on state (with an inactive engine). That is, a state where one or more of the electric vehicle systems, such as the vehicle auxiliary equipment, are operational and consuming power before engine start-up. When the control system determines the key-on state, the control system may be configured to: supply electrical power from the photovoltaic module to the heater; and supply a shortfall of electrical power, required to meet a power demand of the heater, from the high voltage battery energy storage system of the electric vehicle system to the heater. In this condition, the supply of power to the heater may be prioritised in expectation of imminent engine startup. In an example, the system may further comprise or connect to one or more temperature sensors configured to generate a signal indicative of a temperature of the catalytic converter. The one or more controllers may be configured to execute machine readable instructions to: receive the signal from the one or more temperature sensors; and control the electrical power supply between the photovoltaic module, the heater and the one or more electric vehicle systems based on a comparison of the indicated temperature of the catalytic converter to a threshold temperature. In this manner, when the threshold temperature is reached, surplus power from the photovoltaic module can be directed away from the heater to other uses. In an example, the control system may be configured to determine a surplus or a shortfall of electrical power supply from the photovoltaic module to the heater based, at least in part, on the comparison of the indicated temperature to the threshold temperature. The control system may, for example, be configured to: control the supply of electrical power from the photovoltaic module to the one or more electric vehicle systems in dependence on determining the surplus of electrical power supply to the heater; and / or control the supply of electrical power from the one or more electric vehicle systems to the heater in dependence on determining the shortfall of electrical power supply to heater. According to another aspect of the invention there is provided a vehicle comprising an engine, a catalytic converter, and a system as described in a previous aspect of the invention. The vehicle may, for example, further comprise the one or more electric vehicle systems electrically connected to the system. According to yet another aspect of the invention there is provided a kit for retrofitting to a vehicle comprising a catalytic converter. The kit comprises: a heater for heating the catalytic converter; and a photovoltaic module for mounting to the vehicle. The photovoltaic module is electrically connectable to the heater and configured to convert sunlight into electrical power for powering the heater to heat the catalytic converter. According to a further aspect of the invention, there is provided a method of energy management for a vehicle comprising an engine, a catalytic converter, a heater for heating the catalytic converter, a photovoltaic module for converting sunlight into electrical power, and one or more electrical vehicle systems. The method comprises: controlling the electric power supply between the photovoltaic module, the heater, and the one or more electric vehicle systems. In an example, controlling the electric power supply between the photovoltaic module, the heater, and the one or more electric vehicle systems, comprises: receiving a signal indicative of a temperature of the catalytic converter from one or more temperature sensors of the vehicle; comparing the indicated temperature of the catalytic converter to a threshold temperature; and controlling the electrical power supply between the photovoltaic module, the heater and the one or more electric vehicle systems based on the comparison. In an example, controlling the electric power supply between the photovoltaic module, the heater, and the one or more electric vehicle systems, comprises: receiving a signal indicative of an activation state of the vehicle from one or more vehicle activation sensors; determining the activation state of the vehicle as one of a plurality of vehicle activation states based on the received signal; and controlling the electric power supply between the photovoltaic module, the heater, and the one or more electric vehicle systems, based on the determined activation state of the vehicle. According to a still further aspect of the invention, there is provided a control system for a vehicle comprising: an engine, a catalytic converter, a heater for heating the catalytic converter, a photovoltaic module for module for converting sunlight into electrical power, and one or more electric vehicle systems. The control system comprises one or more controllers configured to execute machine readable instructions to perform the method described in a previous aspect of the invention. According to another aspect of the invention, there is provided a computer program product, comprising computer readable instructions which, when the program is executed by one or more processors cause the one or more processors to perform the method described in a previous aspect of the invention. According to yet another aspect of the invention, there is provided a computer readable medium comprising instructions which, when executed by a computer, cause the computer to perform the steps of the method described in a previous aspect of the invention. Within the scope of this application, it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DECRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic illustration of a plan view of a vehicle, in accordance with an embodiment of the invention, with an overlay of an exemplary system for heating a catalytic converter of the vehicle; Figure 2 schematically illustrates a first exemplary arrangement of a heater of the system, shown in Figure 1, for heating the catalytic converter; Figure 3 schematically illustrates a second exemplary arrangement of a heater of the system, shown in Figure 1, for heating the catalytic converter; Figure 4 schematically illustrates an exemplary control architecture for the system, shown in Figure 1, in accordance with an embodiment of the invention; Figure 5 is a schematic illustration of an exemplary controller, in accordance with an embodiment of the invention, for the system shown in Figure 1; and Figures 6 and 7 schematically illustrate an exemplary method of operating the system in accordance with an embodiment of the invention. DETAILED DESCRIPTION Embodiments of the present invention relate to systems and methods for heating a catalytic converter of a vehicle, such as a passenger car, having an internal combustion engine (ICE). The ICE may be a spark ignition (SI) engine or a compression ignition (Cl) engine and may, for example, be petrol-fuelled or diesel-fuelled respectively. The vehicle includes catalytic converter(s) for converting components of the exhaust gases into less toxic or polluting forms. For example, such catalytic converters may include a two-way catalytic converter, a three-way catalytic converter, a diesel oxidation catalyst, and / or a selective catalytic reduction (SCR) system, amongst others. In examples, the vehicle may also include an electric drive or propulsion system and the vehicle may therefore also take the form of a hybrid vehicle, such as a hybrid electric vehicle (HEV). In order to minimise the polluting emissions from the engine, particularly during startup, the methods and systems of the present invention include a heating device or heater for heating the catalytic converter(s) and a photovoltaic module that provides a source of electrical power for the heater. The photovoltaic module is attachable to an exterior surface of the vehicle and configured to convert sunlight into electrical power. The generated electrical power is supplied to the heating element to heat the catalytic converter(s) and, advantageously, the power supply is therefore available whenever the photovoltaic module is exposed to sufficient lighting. In this manner, the catalytic converter(s) can be heated, even while the vehicle is shut-down or in a key-off state, thereby readying the catalytic converter(s) for efficient operation when the engine is subsequently activated. It is envisaged that embodiments of the invention will therefore lead to a reduction of polluting emissions from the vehicle, particularly in urban driving scenarios, without compromising the energy availability for other electric systems onboard the vehicle. Embodiments of the invention shall now be discussed in more detail with reference to Figures 1 to 7. Figure 1 shows a plan view of a vehicle 100 with a schematic overlay of a system 102 for heating a catalytic converter 110 in accordance with an embodiment of the invention. In this example, the vehicle 100 takes the form of a HEV, such as a passenger car, with a powertrain that includes both internal combustion and electric drive systems. The vehicle 100 is therefore shown to include an engine 106, which forms part of the internal combustion drive system, and an electric machine 108, such as an electric motor, that forms part of the electric drive system 109 for improving the fuel economy of the vehicle 100. This example is not intended to be limiting on the scope of the invention though and, in other examples, the vehicle 100 may take various other forms, such as a bus, truck, or train, amongst other passenger vehicles. Moreover, the vehicle powertrain is not limited to a hybrid arrangement and, in other examples, the vehicle powertrain may take various suitable forms including at least one internal combustion engine as a source of drive for the vehicle 100. The engine 106 may take the form of a petrol-fuelled or diesel-fuelled engine, for example, which is connected to an exhaust system (not shown in Figure 1), through which exhaust gases are expelled from the engine 106. However, the exhaust gasses output from the engine 106 may contain toxic gases and pollutants, such as nitrogen oxides, carbon monoxide, and hydrocarbons. Advantageously, the vehicle 100 therefore includes one or more catalytic converters 110 for mitigating the polluting effects of such exhaust gases. That is, the catalytic converter(s) 110 are configured to catalyse redox reactions of the exhaust gases, and thereby convert toxic compounds and pollutants in the exhaust gasses into less harmful forms. To give an example, the catalytic converter(s) 110 may include a three-way catalytic converter for: (i) the reduction of nitrogen oxides into nitrogen and oxygen, (ii) the oxidation of carbon monoxide into carbon dioxide, and (iii) the oxidation of hydrocarbons into carbon dioxide and water. It shall be appreciated that the catalytic converter(s) 110 will vary depending on the nature and configuration of the engine 106 and the exhaust gases generated by its operation. In examples, the catalytic converter(s) 110 may therefore include a two-way catalytic converter and / or a three-way catalytic converter for treating the exhaust gases of a petrol-fuelled engine. In other examples, the catalytic converter(s) 110 may include a diesel oxidation catalyst and / or a selective catalytic reduction (SCR) system for treating the exhaust gases of a diesel-fuelled engine. Other variations are also envisaged. The electric machine 108 may take various suitable forms for propelling the vehicle 100 and requires a high-voltage source of electric power. For context, electric traction motors typically operate at voltage levels greater than or equal to 240V, and more commonly between 400 and 800 Volts. Herein, the term ‘high-voltage’ is therefore used to refer to voltage levels suitable for powering an electric drive system of the vehicle 100 and may correspond to voltage levels that are greater than or equal to approximately 240 V, for example between 400 V and 800 V. Meanwhile, the term ‘low-voltage’ is used to refer to the relatively low voltage levels typically used to power the vehicle auxiliary equipment. For example, the ‘low-voltage’ may therefore correspond to a voltage level of approximately 12 V. The electric machine 108 is electrically connected to an onboard battery energy storage system 112 of the vehicle 100, such as a high-voltage (HV) battery 112, which forms part of the electric drive system 109 and provides the HV source of electrical power. The HV battery 112 is a rechargeable battery, also known as a traction battery, which may typically take the form of a lithium-ion battery or battery pack, for example, having a high power-to-weight ratio and energy density. The HV battery 112 can be recharged at a charging station, by connection to an electric grid, and / or by one or more energy recovery systems of the vehicle 100, such as a regenerative braking system. In this example, the electric drive system 109 is one of a number of electric vehicle systems 111 onboard the vehicle 100 that require an electric power supply during vehicle operation. For example, the vehicle 100 is further shown to include an auxiliary system 114, comprising electrical connections to a range of conventional auxiliary vehicle equipment 113, such as the windscreen wipers, air conditioning system, and / or window systems, that require electric power during vehicle operation. The auxiliary system 114 may operate at a relatively low voltage, e.g. approximately 12V, and may therefore further include power conversion equipment, such as a DC-to-DC converter (not shown) for voltage reduction between the HV and V systems. Additionally, the auxiliary system 114 may include a battery energy storage system, such as a 12 V or low-voltage (LV) battery 115, that stores electrical power for the auxiliary vehicle equipment 113. The LV battery 115 is able to provide power to the auxiliary vehicle equipment 113 in a key-on state of the vehicle 100, prior to engine startup. The system 102 is also shown to include a heating device or heater 118 for heating the catalytic converter(s) 110 and, advantageously, further includes a photovoltaic module 116 for supplying power to the heater 118. The photovoltaic module 116 may include one or more solar panels or solar arrays, comprising an array of photovoltaic cells connected together to generate sufficient power for heating the catalytic converter(s) 110. To give an example, the solar panel may include between 500 and 1000 photovoltaic cells connected together to produce a high-voltage output suitable for heating the catalytic converter(s) 110 towards their activation temperature. The photovoltaic module 110 may therefore be configured to generate a ‘high-voltage’ nominal output, for example producing a nominal output voltage of at least 240 V or at least 400 V. For this purpose, the photovoltaic cells may be made of semiconductor materials such as silicon and alloys of indium, gallium and nitrogen, for example. The cells may be mounted on an exterior of the vehicle 100, for example on a roof structure of the vehicle 100, as schematically illustrated in Figure 1. The heater 118 is configured to heat the catalytic converter(s) 110 using electrical power supplied from the photovoltaic module 116, and may include one or more heating elements for this purpose. The heater 118 may be configured to heat the catalytic converter(s) 110 to a target temperature, which may be greater than or equal to a minimum activation temperature of the catalytic converter(s) 110, for example. For context, modern three-way catalysts typically become active at temperatures of around 250 to 400 °C, and the target temperature of the heater 118 may therefore be approximately 250 °C, for example. In examples, it shall be appreciated that the vehicle 100 may include a plurality of heaters, particularly if the vehicle 100 includes multiple catalytic converters 110, and each heater 118 may be configured to heat a respective catalytic converter 110. For example, each heater 118 may be configured to heat one of the catalytic converter(s) 110 to its respective minimum activation temperature. Figures 2 and 3 schematically show exemplary embodiments of the heater 118 arranged in an exhaust system 120 of the vehicle 100 for heating an exemplary catalytic converter 110. The exhaust system 120 is shown to include a first duct 122 extending from an outlet of the engine 106 to the catalytic converter 110, and a second duct 124 that extends from the catalytic converter 110 to an outlet 126 of the exhaust system 120. The exhaust gases generated by the engine 106 therefore enter the exhaust system 120 along the first duct 122 and pass through the catalytic converter 110, where a redox reaction is catalysed to convert toxic gasses and pollutants in the exhaust gas into less harmful forms. The treated exhaust gas subsequently flows from the catalytic converter 110 through the second duct 124 and passes into the external environment through the outlet 126. Figure 2 shows a first embodiment in which the heater 118 is coupled to the catalytic converter 110, and arranged to heat the catalytic converter 110 directly. Figure 3 shows an alternative embodiment, in which the heater 118 is arranged upstream of the catalytic converter 110, in the first duct 122, to heat the catalytic converter 110 indirectly (by transferring heat to the exhaust gas travelling through the first duct 122 before it reaches the catalytic converter 110). It shall be appreciated that the first embodiment, shown in Figure 2, may provide a relatively efficient heating arrangement, whilst the arrangement shown in Figure 3 may provide relative advantages in terms of the ease of manufacture, or even the ease of retrofitting the system 102 to a vehicle 100. These exemplary layouts are provided by way of example only though and are not intended to be limiting on the scope of the invention. The photovoltaic module 116 generates electrical power whenever the photovoltaic cells are exposed to adequate sunlight and the photovoltaic module 116 can therefore power the heater 118 even while the vehicle 100 is shut-down, in a key-off state. In this manner, the system 102 can heat the catalytic converter(s) 110 to an above-ambient temperature, such as a temperature at or above the minimum activation temperature, whilst the vehicle 100 is not in use. Consequently, the vehicle 100 is prepared for efficient operation upon engine start-up and the warm-up period of the catalytic converter(s) 110 is substantially reduced or negated. The catalytic converter(s) 110 are therefore able to effectively catalyse the redox reactions at, or shortly after, engine start-up, leading to significant reductions in the polluting emissions from the vehicle 100 following a cold-start. In examples, the electric power supply from the photovoltaic module 116 may be actively or passively controlled. For example, in a passive control arrangement, the photovoltaic module 116 may be electrically connected to the heater 118 and arranged to supply electrical power directly to the heater 118, whenever such power is available. In other examples, the photovoltaic module 116 may be configured to act as an electric power source for multiple electric vehicle systems, including the heater 118, and the system 102 may include an energy management system or control architecture for actively controlling the power distribution amongst such systems. To give an example, Figure 4 schematically illustrates an exemplary control architecture for controlling the power supply between the photovoltaic module 116, the heater 118, and the electric vehicle systems 111. For this purpose, the system 102 is shown to include electric circuitry 121 connecting the photovoltaic module 116, the heater 118, the electric drive system 109 and the auxiliary system 114 together. The auxiliary system 114 and the electric drive system 109 are each connected via their respective batteries 115, 112 and, although not shown in Figure 4, it shall be appreciated that the electric system 121 may also include power conversion equipment for stepping up I down the voltage level, as required. The electric circuitry 121 is also shown to include a plurality of switch devices 151, such as electric relays, operable to control the respective electrical connections between the photovoltaic module 116, the heater 118, the electric drive system 109, and the auxiliary system 114. The system 102 further includes one or more controllers that collectively form a control system 150 configured to operate the switch devices 151 and thereby control the electrical connections. In this manner, the power distribution is effectively controlled by the control system 150, which acts as an energy management system (EMS). In order to inform the energy management, the control system 150 is configured to receive signals from one or more sensors and to control the switch devices 151 based thereon. To give an example, Figure 4 shows the control system 150 connected to one or more heating sensors 152 configured to monitor the catalytic converter(s) 110 and one or more vehicle activation sensors 154 configured to generate signals indicative of an activation state of the vehicle 100. The control system 150 may therefore be configured to: (i) receive signals that are indicative of the temperature of the catalytic converter(s) 110 from the heating sensor(s) 152, and (ii) control the power supply power to the heater 118 in dependence on the indicated temperature. For example, the control system 150 may be configured to receive signals from the heating sensor(s) 152 and operate the switch devices 151 to supply power to the heater 118 while such signals indicate that the temperature of the catalytic converter(s) 110 is less than or equal to a threshold temperature. The threshold temperature may correspond to the minimum activation temperature of the catalytic converter(s) 110, for example. If the control system 150 determines that the indicated temperature is greater than or equal to the threshold temperature, the control system 150 may instead operate the switch devices 151 to supply the excess power from the photovoltaic module 116 to the auxiliary system 114 and / or the electric drive system 109. In this manner, the control system 150 may be configured to determine a surplus or a shortfall of electrical power supply from the photovoltaic module 116 to the heater 118 based on a comparison of the indicated temperature to the threshold temperature, and control the switch devices 151 accordingly by generating corresponding control signals. In examples, the control system 150 may additionally or alternatively be configured to: (i) receive signals indicative of an activation state of the vehicle 100 from the vehicle activation sensor(s) 154, and (ii) control the switch devices 121 according to the indicated vehicle activation state. For example, the vehicle activation sensors 154 may generate signals indicative that the vehicle 100 is in one of three states, namely: a key-off state, a key-on state, or an engine active state. The key-off state is a shutdown state of the vehicle 100, when the vehicle 100 is not in use. The key-on state is a wake or activate state of the vehicle, prior to engine startup. Accordingly, during the key-on state, the electric systems of the vehicle 100 are active, but the engine 106 is inactive. In the engine-active state, the engine ignition has been activated and the engine 106 is operational and generating power. Hence, the vehicle activation sensor(s) 154 may take various suitable forms that may be configured to monitor an ignition system and / or a startup system of the vehicle 100 to determine the vehicle activation state. If the control system 150 receive a signal indicating that the vehicle 100 is in the key-off state, the control system 150 may be configured to operate the switch devices 121 to: (i) supply electrical power from the photovoltaic module 116 to the heater 118, and (ii) supply excess power, if any, to the HV battery 112. If the control system 150 receives a signal indicating that the vehicle 100 is in the key-on state, the control system 150 may be configured to prioritise the power supply to the heater 118 and operate the switch devices 121 to: (i) supply electrical power from the photovoltaic module 116 to the heater 118, and (ii) satisfy the power demand of the heater 118 by providing any shortage of electrical power from the HV battery 112 and / or the LV battery 115. However, if the control system 150 receives a signal indicating that the vehicle 100 is in the engine-active state, the control system 150 may be configured to prioritise other systems and operate the switch devices 121 to supply electric power from the photovoltaic module 116 directly to the LV battery 115 instead. Any combination of the above is also possible, for example, if it is determined that the catalytic converter(s) 110 are at or above the threshold temperature, the control system 150 may be configured to: (i) supply the excess electrical power to the HV battery 114 if the vehicle 100 is in the key-off state; or (ii) supply the excess electrical power to the LV battery 115 if the vehicle 100 is in the key-on or engine-active state. In order to control such power supply, even when the vehicle 100 is in the shut-down or key-off state, it shall be appreciated that the control system 150 may include one or more low energy controller configured to remain operational while the vehicle 100 is inactive. Such controllers may include or otherwise interact with a remote keyless entry system of the vehicle 100, for example, and the controllers may be powered by a battery system thereof or via the photovoltaic module 116. Figure 5 provides a schematic illustration of an exemplary controller 160 of the control system 150, which is shown to include an input module 162, an output module 164, a processor module 166, and a memory module 168. That is, Figure 5 shows an exemplary embodiment of a controller 160 of the control system 150, including four functional elements, units or modules. Each of these units or modules may be provided, at least in part, by suitable software running on any suitable computing substrate using conventional or customer processors and memory. Some or all of the units or modules may use a common computing substrate (for example, they may run on the same server) or separate substrates, or different combinations of the modules may be distributed between multiple computing devices. The example architecture of the controller 160 is not intended to be limiting on the scope of the invention though and, in other examples, it shall be appreciated that the architecture may take other suitable forms. The input module 162 is electrically connected to the heating sensor(s) 152 and the vehicle activation sensor(s) 154. The input module 162 is therefore configured to receive signals that are indicative of the temperature of the catalytic converter(s) 110 and / or the activation state of the vehicle 100, amongst other inputs, such as the connection state of the switch devices 151. The processor module 166 is configured to: (i) process the signals received at the input module 162 and (ii) determine one or more control signals for operating the switch devices 151 based on the indicated vehicle state and / or the indicated temperature of the catalytic converter(s) 110. For this purpose, the processor module 166 may use one or more schemes, rules, or algorithms and / or access one or more look-up tables, prescribing respective connection states of the electrical switches 151 corresponding to respective information received from the sensors 152, 154. For example, the processor module 166 may access one or more look-up tables comprising data comprising one or more prescribed connection states of the switch devices 151 corresponding to an indicated temperature of the catalytic converter(s) 110 and / or activation state of the vehicle 100. The data in the one or more look-up tables may be preprogramed into the processor 166, for example by the manufacturer. It shall be appreciated that such look-up tables may be stored in the memory module 168 of the controller 160 and accessed by the processor module 166 to determine the control signal(s). The output module 164 is connected to each of the switch devices 151 and configured to output the determined control signals in order to manage the power distribution. That is, the output module 164 is configured to output the determined control signals to respective ones of the electrical switch devices 151 to control the electrical connections between the photovoltaic module 116, the heater 118, the electric drive system 109, and the auxiliary system 114. To give an example, during driving, the input module 162 may receive a signal indicative of an engine-active state and the output module 164 may output corresponding control signal(s) to the switch devices 151 so as to supply the auxiliary system 114 with the electric power generated by the photovoltaic module 116. However, if the vehicle 100 is subsequently stopped and shut-down, the controller 160 will receive a corresponding signal indicative of a key-off state of the vehicle 100, and the output module 164 may output corresponding control signal(s) to the switch devices 151 to redirect the supply of electrical power from the photovoltaic module 116 to the heater 118. In this manner, the system 102 is configured to effectively manage the power distribution from the photovoltaic module 116, and prioritise the supply of electrical power to the heater(s) 118 whenever the engine is inactive. In this manner, system 102 is able to raise the temperature of the catalytic converter(s) 110 and thereby reduce a warm-up period for effective catalysis following engine start-up. Shortly after engine startup, further heating of the catalytic converter(s) 110 is no longer required for effective catalysis, and the control system 150 can instead direct the excess power supply, generated by the photovoltaic module 116, to the auxiliary system 114 for effective use. Advantageously, the invention therefore serves to reduce polluting emissions from the engine 106, particularly during start-up, and the invention maximises the usefulness of the power generated by the photovoltaic module 116. A method of operating the heating system 102 shall now be described in more detail with additional reference to Figures 6 and 7. Figures 6 and 7 show an exemplary method 200 of operating the system 102, in accordance with an embodiment of the disclosure. In step 202, the control system 150 receives a signal from the vehicle activation sensor(s) 154. The vehicle activation sensor(s) 154 may monitor an ignition system of the vehicle 100, for example, and the received signal may be indicative of whether the vehicle 100 is in one of a key-off state, a key-on state, or an engine-active state. That is, the received signal may indicate, in a binary manner, one of three possible states of the vehicle 100 based on inputs from a user to the ignition system. In step 204, the control system 150 checks if the vehicle 100 is in a key-off state based on the received signal. If the control system 150 determines that the vehicle 100 is in the key-off state, the control system 150 is configured to control the switch devices 151 to supply the heater 118 with electrical power from the photovoltaic module 116, in step 206. For example, the control system 150 may operate the switch devices 151 to ensure that all of the power generated by the photovoltaic module 116 is directed to the heater 118 for the purpose of heating the catalytic converter(s) 110. In this manner, the heater 118 is supplied with electrical power from the photovoltaic module 116, while the vehicle 100 is shut-down, in the key-off state. The heater 118 provides heat to the catalytic converter(s) 110 during this time, increasing or maintaining an above-ambient temperature of the catalytic converter(s) 110 while the vehicle 100 is not in use. The control system 150 may continue to heat the catalytic converter(s) 110 while power remains available from the photovoltaic module 116. However, in examples, the power available from the photovoltaic module 116 may be greater than the demand of the heater 118 for heating the catalytic converter(s) 110 to a desired temperature, such as a minimum activation temperature. In examples, the controller 150 may therefore be configured to direct such power to other electrical vehicle systems for other uses. As shown in Figure 6, the control system 150 may therefore receive a signal from the temperature sensor(s) 152, in step 208. The temperature sensor(s) 152 monitor the catalytic converter(s) 110 and output one or more signals indicative of the temperature(s) of the catalytic converter(s) 110. The control system 150 compares the indicated temperature of the catalytic converter(s) 110 to a threshold temperature, in step 210. The threshold temperature may correspond to a temperature at or above the minimum activation temperature of a respective catalytic converter 110, for example, or any other desired temperature. If the indicated temperature is less than the threshold temperature, the control system 150 may continue to supply all of the electrical power generated by the photovoltaic module 116 to the heater 118 and the method 200 may return to step 202 for a subsequent iteration. Otherwise, if the indicated temperature is greater than or equal to the threshold temperature, the control system 150 may control the switch devices 151 to connect the photovoltaic module 116 to the HV battery 112, in step 212, and thereby supply the HV battery 112 with the excess power. In this manner, the photovoltaic module 116 therefore serves, in the first instance, to heat the catalytic converter(s) 110 and thereby reduce or negate the warm-up period, following startup, and, in the second instance, supplies excess power to the HV battery 112 for storage. The photovoltaic module 116 may therefore further help to recharge the HV battery 112 while the vehicle 100 is not in use. Thereafter, the method 200 may proceed to step 202 for a subsequent iteration. If it is determined, in step 204, that the vehicle 100 is not in a key-off state based on the received signal, the control system 150 proceeds to check, in step 214, if the vehicle 100 is in a key-on state based on the received signal. If the control system 150 determines that the vehicle 100 is in the key-on state, the other electric vehicle systems 111 may also be operational and consuming electric power, but the heating of the catalytic converter(s) 110 is prioritised over the other electrical vehicle systems 111 in anticipation of imminent engine activation. In step 216, the control system 150 is therefore configured, once again, to control the switch devices 151 to supply the heater 118 with electrical power from the photovoltaic module 116. For example, the control system 150 may operate the switch devices 151 to ensure that all of the power generated by the photovoltaic module 116 is directed to the heater 118 for the purpose of heating the catalytic converter(s) 110. However, in order to prioritise the heating of the catalytic converter(s) 110 whilst in the key-on state, the control system 150 may further operate the switch devices 151 to connect one or more of the other electric vehicle systems 111 to the heater 118, drawing additional power from the stored energy reserves to maximise the energy available for heating the catalytic converter(s) 110. To inform such control, the control system 150 may therefore receive a signal from the temperature sensor(s) 152, in step 218, and compare the indicated temperature a threshold temperature, in step 220, which may be greater than or equal to the threshold temperature used in step 210. If the indicated temperature is greater than or equal to the threshold temperature, the control system 150 may control the switch devices 151 to connect the photovoltaic module 116 to the auxiliary system 114, in step 224, and thereby supply the LV battery 114 with the excess power for powering the auxiliary systems 114 of the vehicle 100. In this manner, the photovoltaic module 116 therefore serves, in the first instance, to heat the catalytic converter(s) 110 and reduce or negate the warm-up period, and, in the second instance, supplies excess power to the LV battery 114 to replenish the energy available for operating the auxiliary equipment 113 of the vehicle 100. Thereafter, the method 200 may proceed to step 202 for a subsequent iteration. Alternatively, if the indicated temperature is less than the threshold temperature, the control system 150 may instead control the switch devices 151 to connect the HV battery 112 to the heater 118, in step 222, and thereby supply the heater 118 with a power shortfall from the energy stored in the HV battery 112. In this manner, the heater 118 can temporarily draw a power shortage, if needed, from the HV battery 112 to heat the catalytic converter(s) 110 prior to startup of the engine 106. Thereafter, the method 200 may proceed to step 202 for a subsequent iteration. Referring to Figure 7, if it is determined, in step 214, that the vehicle 100 is not in a key-on state based on the received signal, the control system 150 proceeds to check, in step 226, if the vehicle 100 is in an engine-active state based on the received signal. If the control system 150 determines that the vehicle 100 is in the engine-active state, the engine 106 is combusting fuel and the exhaust gases heat the catalytic converter(s) 110. In this state, the catalytic converter(s) 110 are likely to be at temperatures greater than or equal to their minimum activation temperature(s) and able to effectively catalyse redox reactions. Upon determining that the vehicle 100 is in the engine-active state, the control system 150 may therefore prioritise the supply of excess power to the auxiliary system of the vehicle. Accordingly, the control system 150 may be configured to receive a signal from the temperature sensor(s) 152, in step 228, and compare the indicated temperature to a threshold temperature, in step 230, which may be greater than or equal to the threshold temperature used in step 210 or 220. If the indicated temperature is greater than or equal to the threshold temperature, the control system 150 may control the switch devices 151 to connect the photovoltaic module 116 to the auxiliary system, in step 234, and thereby supply the LV battery 114 with the excess power for powering the auxiliary systems 114 of the vehicle 100. Thereafter, the method 200 may proceed to step 202 for a subsequent iteration. Alternatively, if the indicated temperature is less than the threshold temperature, for example immediately after engine startup, the control system 150 may control the switch devices 151 to supply the heater 118 with electrical power from the photovoltaic module 116, in step 232. For example, the control system 150 may operate the switch devices 151 to ensure that at least some of the power generated by the photovoltaic module 116 is directed to the heater 118 for the purpose of heating the catalytic converter(s) 110. Thereafter, the method 200 may again proceed to step 202 for a subsequent iteration. In this manner, the control system 150 provides for effective energy management between the photovoltaic module 116, the heater 118, and the additional electric vehicle system 111, such that the catalytic converter(s) 110 are effectively heated, even when the vehicle 106 is shut-down or in a key-off state. As a result, the system 102 provides effective catalysis of the exhaust gases. Such energy management will lead to a reduction of polluting emissions from the vehicle 110, particularly in urban driving scenarios, without compromising the energy availability for other electric systems 111 onboard the vehicle 100. It is noted that the steps of the method 200 described are merely exemplary in nature and are not intended to limit the energy management method. As such, it is understood that the steps involved may be altered, reordered, added and removed as will be appreciated by the person skilled in the art. It will also be appreciated that various changes and modifications can be made to the examples described above without departing from the scope of the present invention. In other examples, the control system 150 may be configured to operate the switch devices 151 without reference to the vehicle activation state, for example, and instead simply supply power from the photovoltaic module 116 to the heater 118 whenever the temperature is less than the threshold temperature. If the control system 150 determines that the indicated temperature is greater than the threshold temperature, the control system 150 may further be configured to supply excess power from the photovoltaic module 116 to one of the other electric vehicle systems 111. In other examples, the control system 150 may be configured to operate the switch devices 151 without reference to the temperature of the catalytic converter(s) 110. For example, the control system 150 may be configured to: (i) connect the photovoltaic module 116 to the heater 118 whenever the key-off state is detected; (ii) connect the photovoltaic module 116, and optionally the HV battery 112, to the heater 118 whenever the key-on state is detected; and (iii) connect the photovoltaic module 116 to the auxiliary system 114, and optionally the heater 118, whenever the engine-active state is detected.

Claims

1. A system for heating a catalytic converter of a vehicle, the system comprising:a heater for heating the catalytic converter; anda photovoltaic module for mounting to the vehicle;the photovoltaic module being electrically connected to the heater and being configured to convert sunlight into electrical power for powering the heater to heat the catalytic converter.

2. A system according to claim 1, wherein the system is electrically connectable to one or more electric vehicle systems for energy management of the heater and the photovoltaic module, the one or more electric vehicle systems comprising:an electric drive system, and / oran auxiliary system for auxiliary equipment of the vehicle.

3. A system according to claim 2, wherein each electric vehicle system includes a respective battery energy storage system for electrical connection to the photovoltaic module and the heater.

4. A system according to claim 3, wherein the one or more electric vehicle systems include the electric drive system and the auxiliary system, and wherein the electric drive system includes a high voltage battery energy storage system and the auxiliary system includes a low voltage battery energy storage system.

5. A system according to any of claims 2 to 4, further comprising a control system configured to control the electrical power supply between the photovoltaic module, the heater and the one or more electric vehicle systems.

6. A system according to claim 5, further comprising one or more vehicle activation sensors configured to generate a signal indicative of an activation state of the vehicle, wherein the control system includes one or more controllers configured to execute machine readable instructions to:receive the signal from the one or more vehicle activation sensors;determine the activation state of the vehicle as one of a plurality of vehicle activation states based on the received signal; andcontrol the electrical power supply between the photovoltaic module, the heater and the one or more electric vehicle system based on the determined activation state of the vehicle.

7. A system according to claim 6, wherein the plurality of activation states includes a key-off state of the vehicle, and the control system is configured to supply electrical power from the photovoltaic module to the heating element when the control system determines the key-off state of the vehicle.

8. A system according to claim 7, when dependent on claim 3, wherein the control system is configured to supply a surplus of electrical power, exceeding a power demand of the heater, from the photovoltaic module to the battery energy storage system of at least one of the one or more electric vehicle systems when the control system determines the key-off state of the vehicle.

9. A system according to any of claims 6 to 8, wherein the plurality of activation states includes an engine-active state of the vehicle, and the control system is configured to supply electrical power from the photovoltaic module to the one or more electric vehicle systems when the control system determines the engine-active state.

10. A system according to claim 9, when dependent on claim 7, wherein the control system is configured to reduce the supply of electrical power from the photovoltaic module to the heater between determining the key-off state and the engine-active state.

11. A system according to claim 9 or claim 10, wherein the control system is configured to supply a shortfall of electrical power, required to meet a power demand of the heater, from the photovoltaic module to the heater when the control system determines the engineactive state.

12. A system according to any of claims 6 to 11, when dependent on claim 4, wherein the plurality of vehicle activation states includes a key-on state with an inactive engine and, when the control system determines the key-on state, the control system is configured to: supply electrical power from the photovoltaic module to the heater; andsupply a shortfall of electrical power, required to meet a power demand of the heater, from the high voltage battery energy storage system of the electric vehicle system to the heater.

13. A system according to any of claims 5 to 12, further comprising one or more temperature sensors configured to generate a signal indicative of a temperature of the catalytic converter; wherein the one or more controllers are configured to execute machine readable instructions to:receive the signal from the one or more temperature sensors; andcontrol the electrical power supply between the photovoltaic module, the heater and the one or more electric vehicle systems based on a comparison of the indicated temperature of the catalytic converter to a threshold temperature.

14. A system according to claim 13, wherein the control system is configured to determine a surplus or a shortfall of electrical power supply from the photovoltaic module to the heater based, at least in part, on the comparison of the indicated temperature to the threshold temperature; and wherein the control system is configured to:control the supply of electrical power from the photovoltaic module to the one or more electric vehicle systems in dependence on determining the surplus of electrical power supply to the heater; and / orcontrol the supply of electrical power from the one or more electric vehicle systems to the heater in dependence on determining the shortfall of electrical power supply to heater.

15. A vehicle comprising an engine, a catalytic converter, and a system according to any preceding claim.

16. A vehicle according to claim 15, when dependent on claim 2, further comprising the one or more electric vehicle systems electrically connected to the system.

17. A method of energy management for a vehicle comprising an engine, a catalytic converter, a heater for heating the catalytic converter, a photovoltaic module for converting sunlight into electrical power, and one or more electrical vehicle systems, the method comprising:controlling the electric power supply between the photovoltaic module, the heater, and the one or more electric vehicle systems.

18. A method according to claim 17, wherein controlling the electric power supply between the photovoltaic module, the heater, and the one or more electric vehicle systems, comprises:receiving a signal indicative of a temperature of the catalytic converter from one or more temperature sensors of the vehicle;comparing the indicated temperature of the catalytic converter to a threshold temperature; andcontrolling the electrical power supply between the photovoltaic module, the heater and the one or more electric vehicle systems based on the comparison.

19. A method according to claim 17 or claim 18, wherein controlling the electric power supply between the photovoltaic module, the heater, and the one or more electric vehicle systems, comprises:receiving a signal indicative of an activation state of the vehicle from one or more vehicle activation sensors;determining the activation state of the vehicle as one of a plurality of vehicle activation states based on the received signal; andcontrolling the electric power supply between the photovoltaic module, the heater, and the one or more electric vehicle systems, based on the determined activation state of the vehicle.

20. A control system for a vehicle comprising: an engine, a catalytic converter, a heater for heating the catalytic converter, a photovoltaic module for module for converting sunlight into electrical power, and one or more electric vehicle systems, the control system comprising one or more controllers configured to execute machine readable instructions to perform the method of any of claims 17 to 19.

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