GB2573280A

GB2573280A - Automated charge control

Info

Publication number: GB2573280A
Application number: GB1806759.5A
Authority: GB
Inventors: Owen Simon; Hannis Geoff
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2018-04-25
Filing date: 2018-04-25
Publication date: 2019-11-06
Anticipated expiration: 2038-04-25
Also published as: GB201806759D0; GB2573280B

Abstract

A method for charging a hybrid electric vehicle that has been left unattended for a long period of time, the method comprising determining that the vehicle is stationary, determining a state of charge for the battery, receiving a command from a user to initiate a charging operation to charge the battery, and controlling the internal combustion engine and the electrical machine to charge the battery at a rate dependent upon a charge rate vehicle parameter when the vehicle is stationary and the state of charge for the battery is below a predetermined threshold. Preferably, the parameters could be a charging efficiency, a target battery charge level, a maximum available charge time, or a manually selectable charge rate, and could depend on an optimum engine speed or an optimum electrical machine speed. An output signal may be included to provide real-time feedback of the charging operation. A filter means could be used to disregard minor adjustments to the pedals during charging. Reference is also made to the possible use of a cruise control system, and exhaust gas sensors.

Description

AUTOMATED CHARGE CONTROL

TECHNICAL FIELD

The present disclosure relates to automated charge control. The present disclosure relates particularly, but not exclusively, to controlling the charging operation of a battery in a hybrid electric vehicle and more particularly, but not exclusively, pertains to vehicles powered by an internal combustion engine and an electric battery. Aspects of the invention relate to a method, a system, a controller and a vehicle.

BACKGROUND

As opposed to conventional vehicles, hybrid vehicles typically make use a combination of multiple power sources to improve fuel efficiency. Commonly, manufacturers of hybrid electric vehicles and plug-in hybrid electric vehicles combine a conventional internal combustion engine with an electric propulsion system, sometimes referred to as an electrical machine.

Usually, a hybrid vehicle does not have a traditional alternator and therefore the 12V car battery is not charged directly from the internal combustion engine of the car. Instead, the 12V car battery is reliant on electrical charge received from a high voltage battery used by the hybrid vehicle system. This can cause problems for owners or drivers of hybrid vehicles when they are left unattended and unused for long periods of time. For example, leaving a hybrid vehicle parked in an airport car park whilst away.

In order to charge the high voltage battery of the hybrid vehicle, almost all manufacturers make use of kinetic energy to recharge the main high voltage battery which is often known as regenerative braking.

Another technique known as a manual or command charging operation can be used to resolve the aforementioned problem that drivers and/or owners encounter after having returned to a hybrid vehicle that was left dormant for a long period of time. The manual or command charging operation is implemented by providing torque from the internal combustion engine directly to the electrical machine. This enables the electrical machine to generate electrical energy which is then transferred to the high voltage battery. Additionally, since the internal combustion engine of the vehicle is being used to charge the high voltage battery, the vehicle is required to be in a park mode, where the gearbox is in neutral and the vehicle handbrake is activated.

In most applications of the manual charging operation, the manufacturer’s handbook indicates a manual charge function exists and that it can be activated in the vehicle by applying the accelerator with the “P” or “N” gear selected.

The driver would typically use the state of charge (SoC) indicator on the vehicle to determine when charging of the main battery is complete. Similar to a traditional fuel gauge, an SoC reading or percentage is indicative of the amount of charge the battery is currently holding.

Current implementations of this charging operation lack several key aspects that would enable a more efficient and improved charging operation. An example of such is providing an indication to the driver of the most efficient internal combustion engine revolutions per minute (ICE RPM) value to get an optimum electrical machine (EM) speed to efficiently produce electrical energy. Often a low engine speed (low RPM) results in a longer charge time whereas a high engine speed (high RPM) offers no improvement in charge time relative to an optimal engine speed. Contrary to common belief, a higher RPM does not lead to a faster charge time. Another popular common misconception is that a small but steady increase, followed by a hold, is the best method of manual charging. Even though these presumptions may be incorrect, there is no information related back to the driver to guide them through an efficient charging process. In fact, the selection of a suboptimal RPM by the driver results in unwanted and excess noise, waste of fuel, wear on engine, etc. There are also no restrictions in place stopping a driver from increasing the engine speed over an optimal RPM or once an optimal RPM is reached.

Another common problem is that other than observing the SoC percentage change, the driver is unaware of whether or not the charging function is even active. This often leads to the driver revving the internal combustion engine (ICE) and using fuel without actually charging the main battery.

Since the driving range of a hybrid vehicle depends on the SoC of the main high voltage battery, battery capacities tend to be fairly large. As a result, the time to manually charge a battery may be significant if one intends to fully charge a battery from a low SoC. In current methods, the driver would not normally know how long the charging function will take. Whether this relates to a certain engine speed (ICE RPM) to provide a specific level of battery charge or how long it will take for a complete charge cycle. Often, the driver must remain in the vehicle with their foot on with the acceleration pedal throughout the charging operation.

Along with the driving range of the vehicle, the SoC also determines the enablement of certain vehicle features. For example, the ability to drive the vehicle in a four-wheel-drive (4WD) configuration depends on the amount of charge held in the main battery. Instead of using the traditional methods of regenerative braking or reducing the maximum power of the ICE which may then be used to charge the main battery, drivers may choose to make use of the manual or command charging operation but face the aforementioned problems.

It is therefore an aim of the present invention to enable an extension to the capability of known manual or command charging methods, provide the driver with a user-friendly interface indicative of the charging process and an automated capability to complete a charging cycle through this method and to address one or more of the previously mentioned disadvantages.

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide a method, system, controller and a vehicle as claimed in the appended claims for charging the battery of a hybrid vehicle.

According to an aspect of the present invention there is provided a method for charging a hybrid electric vehicle having an internal combustion engine, an electrical machine and a battery, the method comprising determining that the vehicle is stationary using a first determining means, determining a state of charge for the battery using a second determining means, receiving a command from a user input means to initiate a charging operation to charge the battery, and controlling the internal combustion engine and the electrical machine to charge the battery at a rate dependent upon a charge rate vehicle parameter when the vehicle is stationary and the state of charge for the battery is below a predetermined threshold.

This provides the advantage that the vehicle automatically supports the driver of the car in using a charging operation for the battery. Rather than relying on driver inputs to charge the high voltage battery of the vehicle (from torque provided by the internal combustion engine), the vehicle will control the ICE and the electrical machine to provide the most efficient charging operation. This enables the driver or user of the vehicle to prolong the life of the high voltage battery and protect the battery during extended periods of sedimentary use.

In an embodiment, the charge rate vehicle parameter comprises any combination of a charging efficiency, a target state of charge level for the battery, a maximum available charge time or a manually selectable charging rate.

In this way, the method makes it possible to automatically provide the most efficient transfer of ICE fuel to electrical energy for the battery, through the electrical machine. The charging method may also relate to the most efficient way of charging the battery to reach a certain target state of charge, for example, to enable a particular vehicle drive mode. In some examples, the maximum available charge time can be based on a driver or user’s availability or certain vehicle limitations such as engine fuel level.

In an embodiment, the charge rate vehicle parameter is dependent upon any combination of: an optimum internal combustion engine speed or an optimum electrical machine speed. In this way, the method determines the optimal ICE speed and/or the corresponding electrical machine speed to safely or efficiently meet charging objectives.

In an embodiment, the optimum internal combustion engine speed or optimum electrical machine speed is dependent upon any combination of: internal combustion engine output; electrical machine size; electrical machine rating; connection configuration between the internal combustion engine and the electrical machine; internal combustion engine oil and coolant temperature; battery temperature; internal combustion engine fuel level; a predicted total range calculated using a combination of current engine fuel and current battery state of charge; a signal indicative of a driving style of a user; battery charging limit; time and location of the vehicle; or vehicle altitude and surrounding air pressure. In this way the vehicle automatically considers all the different types of constraints and variables that would affect the charging operation.

In an embodiment, target state of charge is manually adjustable by a user, the maximum available charge time is dependent upon a user input, and the manually selectable charging rate comprises a user manually setting a target engine speed. In addition to the automatic determinations performed by the vehicle, the user may also adjust the charging operation to suit their own specific requirements.

In an embodiment, the method provides an output signal indicative of the charging method in real-time so as to provide the user with feedback of the charging operation. In an embodiment, the output signal provides an indication of at least one of: target RPM, time until battery is fully charged, battery capacity percentage, battery temperature, emission information, air pressure and vehicle range.

This provides the advantage that the user of the vehicle is informed that the charging operation is active and running. In current implementations of this charging method, there is no information relayed back to the driver to indicate what is happening during the charging process other than the SoC gauge changing on the instrument pack.

In hybrid electric vehicles, a small amount of movement in the SoC indicator is noticeable due to the small size of the battery. However, there is usually a delay from the start of the charging operation and the SoC percentage moving to reflect a change in the battery charge. As a result, drivers may not know the charging function is activated and they may stop revving the engine. On a plug-in hybrid vehicle, the SoC indicator movement would not be noticeable and the driver would have no idea if the charge feature is working until quite some time. Many drivers would not free rev their engine for an unknown length of time in the hope that the battery is charging or doing some undefined piece of work.

In an embodiment, a filter configuration is used for disregarding minor adjustments to the pedals during the charging operation. If the driver remains in the vehicle during the charging process, this provides the advantage that movements to the accelerator pedal are ignored and the optimal engine speed is kept constant throughout the charging process.

In an embodiment, the charging operation of the battery is manually terminated by a user by activating a cancellation signal. This enables the driver to override and terminate the charging process. The cancellation signal can be remotely activated by a user via an internet enabled device or can take the form of a braking signal activated by manually pressing the brake pedal whilst in the car.

In an embodiment, the charging operation is initiated by a user manually setting the internal combustion engine speed between 1500 to 2500 rpm. The vehicle can thus actively detect when the driver is looking to initiate the charging process. The driver can either set the engine speed using the accelerator pedal in the car, or remotely by means of an internet enabled device.

In an embodiment, the internal combustion engine speed is maintained using a vehicle cruise control system. This provides the advantage that the driver does not need to keep the accelerator pedal pressed throughout the charging process should they decide to remain in the car. The engine speed level can be maintained by the cruise control system.

In an embodiment, the system comprises an exhaust gas sensor for detecting whether the vehicle is in a confined space. This enables the assessment of whether or not the vehicle is in a safe environment for the charging process to operate in. The exhaust gas sensor may detect an exhaust gas level to determine whether the vehicle is in a confined space.

In an embodiment, the charging operation is disabled when the exhaust gas level is above a predetermined threshold. The predetermined threshold may be indicative of the vehicle being in a confined space and/or be at a level which may be considered to be harmful to human health.

In an embodiment, a stationary vehicle comprises the vehicle being in a park mode. In an embodiment, the park mode comprises activation of a vehicle handbrake and a neutral gearbox.

According to another aspect of the invention, there is provided a system for a hybrid electric vehicle comprising a vehicle motion sensor for determining when the vehicle is stationary; a battery for storing electrical charge, a battery sensor for determining a state of charge for the battery; and an internal combustion engine coupled operable to an electrical machine; wherein the system is configured to receive a command from a user to initiate a charging operation, the charging operation comprising determining that the vehicle is stationary using the vehicle motion sensor, determining that the state of charge of the battery is below a predetermined threshold using the battery sensor and use a controller configured to control the internal combustion engine and the electrical machine to charge the battery at a rate dependent upon a charge rate vehicle parameter. In an embodiment, the system is operable to perform the of the method steps previously mentioned.

According to another aspect of the invention, there is provided a controller for charging a battery in a hybrid electric vehicle, the controller comprising a first input from a vehicle motion sensor for determining when the vehicle is stationary; a second input from a battery sensor for determining a state of charge for the battery; and a third input from a user to initiate a charging operation to charge the battery; wherein the controller is configured to control an internal combustion engine and an electrical machine to charge the battery at a rate dependent upon a charge rate vehicle parameter when the vehicle is stationary and the state of charge for the battery is below a predetermined threshold. In an embodiment, the controller operable to perform the method steps mentioned above.

According to another aspect of the invention, there is provided a vehicle comprising a vehicle motion sensor for determining when the vehicle is stationary; a battery for storing electrical charge; a battery sensor for determining a state of charge for the battery; and an internal combustion engine coupled to an electrical machine; wherein the vehicle is configured to receive a command from a user to initiate a charging operation, the charging operation comprising determining that the vehicle is stationary using the vehicle motion sensor, determining that the state of charge of the battery is below a predetermined threshold using the battery sensor, and use a controller configured to control the internal combustion engine and the electrical machine to charge the battery at a rate dependent upon a charge rate vehicle parameter. In an embodiment, the vehicle operable to perform the method steps mentioned above.

According to yet another aspect of the invention, there is provided a computer program product operable to perform the method steps mentioned above.

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 DESCRIPTION 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 illustrates a block diagram of an example embodiment of the invention;

Figure 2 shows a flow chart showing the logic followed in an example embodiment of the invention;

Figure 3 shows another flow chart illustrating a preferred embodiment of the invention;

Figure 4 shows a flow chart related to the optional features related to the activation of the invention;

Figure 5 shows a flow chart relation to the additional steps relating to the automation of the invention;

Figure 6 shows an example vehicle in accordance with an embodiment of the invention.

DETAILED DESCRIPTION

A method in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figure 3.

With reference to Figure 3, block 300 relates to the activation of the charging method. Further details and optional steps relating to the activation are described with reference to Figure 4.

Figure 4 depicts an example of a sequence of events that take place in order to activate the charging operation of this invention. At block 401, the vehicle first ascertains the SoC of the high voltage battery. High voltage batteries use known battery management systems (BMS) to monitor SOC and the BMS may interface with the rest of the vehicle controllers as required. A low SoC level could be due to the vehicle being left dormant or unused for a long period of time. Alternatively, the SoC may be too low for a particular vehicle driving mode to be activated or the user requires an extended vehicle range using the electric battery.

Next, at block 402, the vehicle receives an indication that the driver wants to initiate the charge operation and checks whether the vehicle is in a park mode, preferably where the handbrake is activated. Once the park mode condition is satisfied, the system will determine if the vehicle is in a mode ready to begin the operation (403). This generally requires the ICE to be running and the gearbox being in neutral.

The system then requires an input from the driver. At block 404, the driver presses the accelerator pedal to increase the engine RPM. In order to make the driver’s intentions clear, a pedal filter will determine whether or not the driver is merely blipping the throttle 405. The pedal filter will also detect if the driver is taking part in emissions tests that require the engine to free rev 406.

Should all these conditions be satisfied and the driver holds the engine speed between 1500 - 2000 rpm (407), the charging operation will be activated.

Referring back to Figure 3, once the charging operation is activated, the next step in the method is to determine a target power or rev count (301). The target rev count is indicative of the optimal internal combustion engine speed and/or the optimal electrical machine speed needed to provide the most efficient charging operation for the high voltage battery of the vehicle. A number of internal and external variables can affect the target rev count.

Examples of internal vehicle variables include engine output, electrical machine size and rating, the ICE to electrical machine connection method (for example, the CIMG load can be calculated to determine the optimal engine speed), ICE oil and coolant temperatures, vehicle cabin heating or cooling demand, temperate of the high voltage battery, the charge and discharge rate of the high voltage battery, a user selected driving mode or style, a manual selection of SoC target by the driver, the ICE fuel level, a combined ICE/EM vehicle range, other vehicle component temperatures, etc.

As an example of how the temperature of vehicle components can affect the charging efficiency, an inverter temperature model can be used to limit the need for cooling the inverter by charging the battery at a lower rate. Alternatively, the battery can be charged at a higher rate and the inverter can be appropriately cooled if the available charging time (for the user) is short and there is enough ICE fuel.

External variables that can affect the charging efficiency include the ambient air temperature, the vehicle location (for example, being in a confined space), distance to the closest known fuel location (using GPS), the time when the charging operation is activated (for example, noise pollution), vehicle altitude, current air pressure, etc.

An indication of the ideal target engine speed, reflective of the most efficient charging operation for any given circumstance, is then indicated to the user using the vehicle’s instrument display panel.

Once the user is aware of the target rev count, as represented by block 302, the user then proceeds to either increase or decrease the engine speed to the indicated level. In some cases, the vehicle can include pedal filters that detect and ignore small amounts of pedal movement in order to allow a smooth and consistent rev count and engine noise level.

As the high voltage battery begins charging, the user has two options of proceeding in the charging operation. The user may decide to proceed by manually operating the charge operation (303) by completing the operation until a full charge. The manual operation can be ended and disabled by the user releasing the accelerator pedal and pressing the brake pedal.

The user also has the option to engage an automated charging function (304) which enables the vehicle to complete the charging operation without any further input from the driver. This feature can be particularly useful when the vehicle has a large high voltage battery that would take a long time to charge.

The automated charging function is explained in more detail with reference to Figure 5. In order to deliver an automated function, the driver must initially set the vehicle up in a state that can allow the function to be initiated (505). For example, the vehicle needs to identify that the driver wants to use the automated charging feature which can activated by a button press or another type of input from the instrument display panel.

User input means could be one or more of, but not limited to, a throttle input, instrument control input or wifi enabled internet / phone / tablet device. User input means could be an existing or new vehicle control button, touch pad, switch or rotary selector. In block 506, the vehicle will use the information panel to display the engine speed that it will use to charge the high voltage battery. At the same time, the vehicle can also inform the user of the time it will take to complete a charge (or to a given value i.e. 80% charge). Before the automated function is enabled, the driver can be presented with options to adjust the charging parameters. For example, the user can then choose to remain with the current optimum charge point/rev count or increase/decrease the charge time to suit their needs. Once, or if, a new charge time is selected, the engine speed will be automatically set to the revised target engine speed.

The driver may also be presented with various information that corresponds to the charging operation. For example, the vehicle may display a target RPM (pre-automation), time of charge, battery percentage increase (as a goal of the charging operation), vehicle range predictions (including range information for the vehicle being in different modes) or a countdown timer to completion.

The automation steps should take no more than 10-15 seconds. After this, the driver could leave the vehicle unattended and allow the vehicle to charge on its own. I some scenarios, there may be a need for the user to confirm that the vehicle is not parked in a garage or closed space in order to avoid air pollution from the exhaust fumes of a running ICE.

Once the automated feature is activated there should not need to be any further input from the user to control the engine speed. The user can stop the automated charging function at any time by pressing the brake pedal or the ignition switch (507).

The invention with the inclusion of optional features is presented in figure 2. This embodiment of the invention starts with an active detection step for the charging operation 201. At block 202, the determination of whether the charging function is activated is assessed. This could relate to one or more of the factors from Figure 4. For example, if the accelerator is pressed and the engine rev count is above a certain threshold and if the vehicle is in a park mode. If this is not the case, the system returns to the active detection mode. If the charging function is activated the system proceeds to the next step.

At decision block 203, the system determines whether the cruise control button is depressed. In this embodiment, the charging operation requires the use of a vehicle’s cruise control function. This option relieves the user from having to manually press the accelerator pedal throughout the charging operation which can be impractical at times. If the cruise control button is enabled, the vehicle will output information on the human machine interface (HMI) to indicate that the vehicle is ready for a charging operation to begin 204.

As a final check before the charging operation, the system will determine whether the vehicle is in a confined space 205. A sensor 205a for the detection of exhaust gasses such as carbon monoxide, carbon dioxide or nitrogen oxide can be used to assess the air quality around the vehicle. If the environment is unsafe 206 to run the charging operation, for example being in a garage, the system will stop the operation 210. In addition to air quality measurement sensors, GPS or other forms of location data can be used to determine the exact location of the vehicle.

If the vehicle is not in a confined space and considered to be in a safe location for the manual charging operation, the user may select options to configure the charging operation 207. This may include charging the battery to a specific level, for a specific amount of time or in order to provide a total vehicle range.

Once the charging parameters have been adjusted by the user, the vehicle enters a charge mode 208 where the ICE is used to efficiently charge the high voltage battery of the vehicle. The vehicle exits the charge mode 210 when the charge operation achieves its desired objective 209.

In addition, although not depicted in any of the figures, the driver may use an internet enabled device, such as a mobile ‘phone or a tablet, to remotely activate, control and monitor the charging operation. For example, the user of a car may use an application on the device to set the engine speed, activate a cancellation or braking signal, or perform any other aforementioned steps.

Figure 6 depicts a vehicle 601 comprising the manual charging system, method and controller according to aspects and/or embodiments disclosed herein.

It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Any system feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure.

Any feature in one aspect may be applied to other aspects, in any appropriate combination. In particular, method aspects may be applied to system aspects, and vice versa. Furthermore, any, some and/or all features in one aspect can be applied to any, some and/or all features in any other aspect, in any appropriate combination.

It should also be appreciated that particular combinations of the various features described and defined in any aspects can be implemented and/or supplied and/or used independently.

Claims

1. A method for charging a hybrid electric vehicle having an internal combustion engine, an electrical machine and a battery, the method comprising:

determining that the vehicle is stationary using a first determining means; determining a state of charge for the battery using a second determining means;

receiving a command from a user input means to initiate a charging operation to charge the battery; and controlling the internal combustion engine and the electrical machine to charge the battery at a rate dependent upon a charge rate vehicle parameter when the vehicle is stationary and the state of charge for the battery is below a predetermined threshold.

2. A method according to claim 1 wherein the charge rate vehicle parameter comprises any combination of:

a charging efficiency;

a target state of charge level for the battery;

a maximum available charge time; or a manually selectable charging rate.

3. A method according to claim 2 wherein the charge rate vehicle parameter is dependent upon any combination of: an optimum internal combustion engine speed or an optimum electrical machine speed.

4. A method according to claim 3 wherein the optimum internal combustion engine speed or optimum electrical machine speed is dependent upon any combination of: internal combustion engine output; electrical machine size; electrical machine rating; connection means between the internal combustion engine and the electrical machine; internal combustion engine oil and coolant temperature; battery temperature; internal combustion engine fuel level; a predicted total range calculated using a combination of current engine fuel and current battery state of charge; a signal indicative of a driving style of a user; battery charging limit; time and location of the vehicle; or vehicle altitude and surrounding air pressure.

5. A method according to claim 2 wherein the target state of charge is manually adjustable by a user.

6. A method according to claim 2 wherein the maximum available charge time is dependent upon a user input.

7. A method according to claim 2 wherein the manually selectable charging rate comprises a user manually setting a target engine speed.

8. A method according to any preceding claim wherein the method provides an output signal indicative of the charging method in real-time so as to provide the user with feedback of the charging operation.

9. A method according to any preceding claim wherein the method comprises a filter means for disregarding minor adjustments to the pedals during the charging operation.

10. A method according to any preceding claim wherein the charging operation of the battery is manually terminated by a user by activating a cancellation signal.

11. A method according to any preceding claim wherein the charging operation is initiated by a user manually setting the internal combustion engine speed between 1500 to 2500 rpm.

12. A method according to claim 11 wherein the internal combustion engine speed is maintained using a vehicle cruise control system.

13. A method according to any preceding claim wherein the system comprises an exhaust gas sensor for detecting whether the vehicle is in a confined space.

14. A method according to claim 13 wherein the charging operation is disabled when the exhaust gas level is above a predetermined threshold.

15. A method according to claim 8 wherein the output signal provides an indication of at least one of: target RPM, time until battery is fully charged, battery capacity percentage, battery temperature, emission information, air pressure and vehicle range.

16. A method according to any preceding claim wherein a stationary vehicle comprises the vehicle being in a park mode.

17. A method according to claim 16 wherein the park mode comprises activation of a vehicle handbrake and a neutral gearbox.

18. A system for a hybrid electric vehicle comprising:

a vehicle motion sensor for determining when the vehicle is stationary;

a battery for storing electrical charge;

a battery sensor for determining a state of charge for the battery; and an internal combustion engine coupled operable to an electrical machine; wherein the system is configured to receive a command from a user to initiate a charging operation, the charging operation comprising determining that the vehicle is stationary using the vehicle motion sensor, determining that the state of charge of the battery is below a predetermined threshold using the battery sensor and use a controller configured to control the internal combustion engine and the electrical machine to charge the battery at a rate dependent upon a charge rate vehicle parameter.

19. A system according to claim 18 operable to perform the method of any of claims 2 to

17.

20. A controller for charging a battery in a hybrid electric vehicle, the controller comprising:

a first input from a vehicle motion sensor for determining when the vehicle is stationary;

a second input from a battery sensor for determining a state of charge for the battery; and a third input from a user to initiate a charging operation to charge the battery;

wherein the controller is configured to control an internal combustion engine and an electrical machine to charge the battery at a rate dependent upon a charge rate vehicle parameter when the vehicle is stationary and the state of charge for the battery is below a predetermined threshold.

21. A controller according to claim 20 operable to perform the method of any one of claims 2 to 17.

22. A vehicle comprising:

a vehicle motion sensor for determining when the vehicle is stationary;

a battery for storing electrical charge;

a battery sensor for determining a state of charge for the battery; and

5 an internal combustion engine coupled to an electrical machine;

wherein the vehicle is configured to receive a command from a user to initiate a charging operation, the charging operation comprising determining that the vehicle is stationary using the vehicle motion sensor, determining that the state of charge of the battery is below a predetermined threshold using the battery sensor, and use a 10 controller configured to control the internal combustion engine and the electrical machine to charge the battery at a rate dependent upon a charge rate vehicle parameter.

23. A vehicle according to claim 22 operable to perform the method of any of claims 2 to

15 17.

24. A computer program product operable to perform the method of any preceding claim.