GB2575078A

GB2575078A - Control system and method

Info

Publication number: GB2575078A
Application number: GB201810592A
Authority: GB
Inventors: Stephen Foster Jaimie; Osborn Russell
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2018-06-28
Filing date: 2018-06-28
Publication date: 2020-01-01
Also published as: GB201810592D0

Abstract

A control system 605 comprising means for converting kinetic energy 645 associated with the movement of a vehicle 600 to electrical energy 650, means for monitoring at least one parameter associated with the operation of the vehicle, means for distributing electrical energy converted from kinetic energy of the vehicle between the energy conversion means and an energy storage device 610 of the vehicle, and between the energy conversion means and at least one further component associated with the vehicle in dependence on data associated with the at least one parameter, the at least one further component comprising at least one of a component of a lubrication circuit 635, a heating or cooling means of the energy storage device, and a heating or cooling means of a component of a drive train. The electrical energy may be distributed in dependence on a charge state of a battery, a charge mode of a battery, or a temperature of a lubricant. Also provided is a control method for a vehicle and a vehicle comprising the above control system.

Description

CONTROL SYSTEM AND METHOD

TECHNICAL FIELD

The present disclosure relates to a control system and method and particularly, but not exclusively, to an electrical energy control system and method. Aspects of the invention relate to a control system for a vehicle, a vehicle, and a control method for a vehicle.

BACKGROUND

Electric vehicles and hybrid electric vehicles are known to use electric drive units for propulsion. When the electric drive unit is engaged, it is often powered by electricity from a battery. An electronic charging station is often used to charge the battery. The electrical energy from the battery can be used to power other electronic components of the vehicle, such as lighting when a light switch is pressed by a user of the vehicle.

Another part of the vehicle that may require energy when the vehicle is in motion or stationary is the lubrication system. The lubrication system may comprise an electrically driven pump for pumping lubricant to various components of the vehicle. Electric and hybrid vehicles include various rotating components that require lubrication, for example the components that form the electric drive unit of the vehicle. In known lubricating systems, a rotating component, such as a ring gear, transfers lubricant to another rotating component, for example a pinion bearing. A disadvantage of such a system is that the lubricant can cause drag on the rotating ring gear, leading to an energy inefficiency known as churn loss. In cold conditions, the lubricant may be highly viscous and thus more energy would be required to generate lubricant flow. This results in increased shearing forces and bearing spin loss. Energy may be required to increase the temperature of the lubricant in order to reduce its viscosity and therefore reduce losses associated with shearing forces. This may be achieved by increasing the flow rate of lubricant in the lubrication system to increase the temperature of the lubricant. Conversely, in warm conditions, the viscosity of the lubricant will be lower compared to when it is at its normal operating temperature. As such, the lubricant film thickness of a component or components supplied by the lubrication system will be lower than when the lubricant is at its normal operating temperature. This will result in increased friction between contacting components supplied by the lubrication system which will generate heat. In this situation, a higher flow rate of lubricant may be required to prevent localised heating. As such, increased energy will be required of the lubricant pump.

An issue with relying on electrical energy from the battery to power the electronic components of the vehicle, such as a lubricant pump, would arise if the battery was depleted of energy and a charging station was not available. In this case, it would not be possible to provide electrical energy to the electronic components and therefore the components would be unable to function. Vehicles that rely on electrical energy from the battery to provide energy to the vehicle’s electronic components may be made more efficient by utilising and converting energy from other parts of the vehicle.

For example, some electric and hybrid electric vehicles are known to adopt a method of converting kinetic energy to electrical energy, which is directed to the battery, through the braking mechanism of the wheels and/or the mass and inertia of the vehicle. This conversion method is known as regenerative braking. One of the disadvantages of known methods of regenerating energy in a vehicle is that the energy is regenerated only when the brakes are engaged. A further disadvantage is that the regenerated energy may be directed only to the battery of the vehicle.

In addition, in some implementations of regenerative braking, if the battery is fully charged, the energy would not be regenerated and utilised. Instead the energy would be lost as waste heat through the friction brakes of the vehicle. This limits the amount of electrical energy available for use in the vehicle to the amount that is stored in the battery.

The present invention has been devised to mitigate or overcome at least some of the above-mentioned issues.

SUMMARY OF THE INVENTION

Aspects of the invention relate to a control system for a vehicle, a vehicle, and a control method for a vehicle as claimed in the appended claims.

According to an aspect of the present invention there is provided a control system for a vehicle comprising: means for converting kinetic energy associated with the movement of the vehicle to electrical energy; means for monitoring at least one parameter associated with the operation of the vehicle; and means for distributing electrical energy converted from kinetic energy of the vehicle between an energy storage device of the vehicle and at least one further component associated with the vehicle in dependence on data associated with the at least one parameter. The at least one further component comprises at least one of: a component of a lubrication circuit, a heating or cooling means of the energy storage device, and a heating or cooling means of a component of a drive train.

It is to be understood that the term ‘drive train’ as used herein refers to a group of components of the vehicle which deliver torque to the driven wheel or wheels of the vehicle from a torque source, such as an internal combustion engine or an electric motor, or the combination thereof, excluding the torque source itself.

An advantage of the present control system is that it is able to decide where electrical energy is required in the vehicle and distribute it accordingly. This decision is made using data associated with at least one parameter. The decision and distribution may be made without user input. A further advantage is that even if the battery is fully charged, the regenerated electrical energy may be used in other parts of the vehicle.

Advantageously, the control system may therefore allow the energy in a vehicle to be directed to the components of the vehicle that require it the most given a current state of the vehicle determined from the parameter data. Further, the control system may be configured to make decisions about which subsystem(s) to distribute the electrical energy to without any external input, for example from the user. The regenerated energy during the use of the vehicle, whether the drive unit is engaged or disengaged, may therefore be managed more efficiently.

The means for distributing electrical energy may distribute electrical energy in dependence on a signal associated with a charge state of a battery.

The means for distributing electrical energy may distribute electrical energy in dependence on a signal associated with a charge mode of a battery.

The means for distributing electrical energy may distribute electrical energy in dependence on a signal associated with a temperature of a lubricant.

The regenerated electrical energy can be directed to subsystems that require energy and not to subsystems that do not require energy. For example, if the battery has a high charge state or if it is fully charged, the electrical energy can be directed to subsystems that require energy instead of the battery. This reduces the generation of waste heat.

Electrical energy may be distributed to the component of a lubrication circuit and one of two pump modes may be activated in use: a first pump mode comprising a predetermined lubricant flow rate; or a second pump mode comprising a lubricant flow rate that is higher than the pre-determined lubricant flow rate. The pre-determined lubricant flow rate is a pre-determined minimum flow rate that provides sufficient lubrication of components provided with lubricant by the lubricant circuit. The pre-determined lubricant flow rate may be associated with an efficient lubricant flow rate for maintaining an optimum lubricant temperature in accordance with one or more requirements of the vehicle.

This allows the lubricant to be pumped at the most suitable flow rate and in turn allows the lubricant temperature to be maintained. For example, if the current battery charge is high and does not require further charging, electrical energy can be distributed to the lubrication circuit and the lubrication pump mode can be set in order to maintain the required lubricant temperature.

The parameter associated with the operation of the vehicle may comprise any one or more of: vehicle condition, state of charge of a battery, battery charge mode, lubricant temperature or inverter temperature.

The data associated with any one or more of these parameters can be used to make the decision about which subsystem(s) to distribute the energy to. No user input is required. This enables the energy in a vehicle to be managed more efficiently.

The data may be associated with signals from at least one sensor.

Sensors can be used to detect temperature, speed, torque and/or any other parameter associated with the operation of the vehicle or the driving conditions. The nature of the decision to distribute electrical energy to the subsystems can be based on a wide range of properties and therefore provide the most energy efficient option for the current state of the vehicle.

The data may be associated with one or more criteria and may be stored on memory storage means.

The data may be associated with one or more models stored on a memory storage means, the model being executed using a processing means.

Advantageously, the data may not have to be obtained when required - it may be available through the memory storage means and this would lead to a faster decision for distributing the electrical energy.

According to an aspect of the present invention there is provided a control method for a vehicle comprising: converting kinetic energy associated with the movement of the vehicle to electrical energy; monitoring at least one parameter associated with the operation of the vehicle; and distributing electrical energy converted from kinetic energy of the vehicle between: a means for converting kinetic energy associated with the movement of the vehicle to electrical energy and an energy storage device of the vehicle, and the means for converting kinetic energy associated with the movement of the vehicle to electrical energy and at least one further component associated with the vehicle in dependence on data associated with the at least one parameter; wherein the at least one further component comprises at least one of: a component of a lubrication circuit, a heating or cooling means of the energy storage device, and a heating or cooling means of a component of a drive train.

Electrical energy may be distributed in dependence on a signal associated with a charge state of a battery.

Electrical energy may be distributed in dependence on a signal associated with a charge mode of a battery.

Electrical energy may be distributed in dependence on a signal associated with a temperature of a lubricant.

The regenerated electrical energy can be directed to subsystems that require energy and not to subsystems that do not require energy. Advantageously this reduces the generation of waste heat. For example, if the battery has a high charge state or if it is fully charged, the electrical energy can be directed to subsystems that require energy instead of the battery.

Distributing electrical energy may comprise electrical energy being distributed to the component of a lubrication circuit and one of two pump modes being activated in use: a first pump mode comprising a pre-determined lubricant flow rate; or a second pump mode comprising a lubricant flow rate that is higher than the pre-determined lubricant flow rate. The pre-determined lubricant flow rate may be a pre-determined minimum flow rate that provides sufficient lubrication of components provided with lubricant by the lubricant circuit. The pre-determined lubricant flow rate may be associated with an efficient lubricant flow rate for maintaining an optimum lubricant temperature in accordance with one or more requirements of the vehicle.

This allows the lubricant to be pumped at the most suitable flow rate and in turn allow the lubricant temperature to be maintained. For example, if the current battery charge is high and does not require further charging, electrical energy can be distributed to the lubrication circuit and the lubrication pump mode can be set in order to maintain the required lubricant temperature.

The regenerated electrical energy can be used to control the temperature of the battery to maximise efficiency and minimise energy loss.

The first pump mode may be activated in response to the battery charge mode being in depletion mode and lubricant temperature being lower than an operating temperature of the vehicle. The second pump mode may be activated in response to the battery charge mode being in depletion mode and lubricant temperature being higher than an operating temperature of the vehicle.

The data may be associated with signals from at least one sensor.

According to an aspect of the present invention there is provided a vehicle comprising a control system as described herein.

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 shows a block diagram of a control system according to an embodiment of the invention;

Figure 2 shows a block diagram of the control system shown in Figure 1 further detailing components of the means for converting kinetic energy associated with the movement of the vehicle to electrical energy;

Figure 3 shows a block diagram of the control system shown in Figure 2 further detailing components of the means for monitoring at least one parameter associated with the operation of the vehicle;

Figure 4 shows a block diagram of the control system shown in Figure 3 further detailing components of the means for distributing electrical energy;

Figure 5 shows a plan view schematic diagram of a vehicle indicating numerous components according to an embodiment of the invention;

Figure 6 shows a plan view schematic diagram of the vehicle shown in Figure 5 comprising a control system, according to an embodiment of the invention; and

Figure 7 shows a plan view schematic diagram of the vehicle shown in Figure 5 comprising a control system, according to a further embodiment of the invention.

DETAILED DESCRIPTION

The present disclosure relates to a control system and method. A vehicle may comprise the control system and method as described herein. The control system and method may be used for distributing electrical energy in a vehicle.

There is presented a control system. The control system comprises: means for converting kinetic energy associated with the movement of the vehicle to electrical energy; means for monitoring at least one parameter associated with the operation of the vehicle; and means for distributing electrical energy converted from kinetic energy of the vehicle between an energy storage device of the vehicle and at least one further component associated with the vehicle in dependence on data associated with the at least one parameter. The at least one further component comprises at least one of: a component of a lubrication circuit, a heating or cooling means of the energy storage device, and a heating or cooling means of a component of a drive train.

An example of the general principle of operation, which can be applied to one or more embodiments described below, of the present disclosure, will now be described. Advantages of the control system are then discussed.

If a user is driving a vehicle and the user puts his or her foot on the brake pedal or releases the throttle, kinetic energy from the motion of the vehicle and wheels may be converted to electrical energy using, for example, an electric generator. In the meantime, a temperature sensor may be used to monitor the temperature of lubricant in a component of the vehicle. In addition, a light sensor may be used to detect the current ambient light level outside the vehicle. The data from the sensors may be transmitted to an electronic processor which may comprise a set of models or rules. The processor may then compare the data to the models or rules. After the comparison, the processor may determine that power is required by both the lighting at the door and the lubrication system. The processor may also determine the amount of power required by these components. The processor may then distribute the regenerated electrical energy to the components accordingly. In the event that the light sensor signal is low and brighter light is required by the user, the processor may distribute energy to the lighting circuit and adjust the brightness according to data from the light sensor. In the event that the temperature of the lubricant in a particular component of the vehicle is lower than the ideal temperature, the processor may distribute energy to the lubrication system to increase the lubricant temperature, for example by directly heating the lubricant or by energising a pump to increasing the flow rate of lubricant into the lubrication system.

An advantage of the present control system is that it is able to decide where electrical energy is required in the vehicle and distributes it accordingly. In particular, the control system is able to decide which subsystems to distribute electrical energy converted from kinetic energy of the vehicle to according to the requirements of said subsystems. As such, the amount of electrical energy converted from kinetic energy of the vehicle that is wasted can be reduced and therefore the overall energy efficiency of the vehicle can be increased. This decision is made using data obtained by monitoring parameters in the vehicle or data stored in memory. The decision and distribution may be made without user input. A further advantage is that even if the battery is fully charged, the regenerated electrical energy may be used in other parts of the vehicle instead of being wasted through conversion to unusable heat energy.

The process of converting kinetic energy from the rotation of the wheels and translation of the vehicle body to electrical energy may be referred to herein as regenerative braking. Advantageously, the present control system and method may permit the conversion of kinetic energy from the movement of any part of the vehicle. This process of regenerating energy utilises energy that would normally be lost as waste heat.

A wide range of parameters may be monitored by one or more sensors in or on the vehicle. For example, a condition of the vehicle (e.g. stationary or in motion); a condition of the battery (e.g. a charge level); or a temperature of a subsystem of the vehicle (e.g. a temperature of the drive train) may be monitored. Additionally or alternatively, the data may be available on a memory storage means.

The control system may distribute the regenerated electrical energy to one or more subsystems of the vehicle that use electrical energy to drive a particular function or output. As an example, the control system may controllably distribute the regenerated electrical energy to one or more components of the powertrain of the vehicle, such as the battery, the inverter, the drive unit(s) and/or the differential.

The decision about which subsystem(s) to distribute electrical energy to may be established using processing means such as, but not limited to, an electronic processor or Electronic Control Unit (ECU).

The term ‘data’ may be, but is not limited to, any one or more of: data associated with the battery or data associated with the drive train of the vehicle; data associated with the occupancy state of the vehicle; data associated with the local environment about the vehicle.

The term ‘vehicle’ may also be referred to herein as a car and in some examples an electric car or hybrid electric vehicle. It is understood that examples referencing an electric car or hybrid electric car may equally refer to other types of cars as well as other types of vehicles. For example, the control system may be used with plug-in hybrid vehicles, which can be charged by an electric charging station, or with conventional hybrid vehicles, which are charged by regenerative braking. Other uses of the control system may be envisaged, for example in the train industry to distribute regenerated energy from braking to different systems or in the toy industry to distribute regenerated energy in a toy train set.

The term ‘subsystem’ may comprise, but is not limited to, a system associated with the battery or a system associated with a lubrication circuit. Examples of subsystems include; a powertrain, a battery cooling means, a battery heating means for adjusting the temperature of the battery, an inverter cooling means, a stator cooling water system or a cooling generator. The battery cooling and heating means may comprise a heat exchanger configured to transfer heat between the battery and a coolant. Similarly, the inverter cooling means may comprise a heat exchanger configured to transfer heat between the inverter and a coolant.

Specific embodiments of the control system will be described below with reference to Figures 1 to 8.

Figure 1 shows a block diagram of a control system 100 for a vehicle according to an embodiment of the invention.

The control system may be placed at any location in or on the vehicle. For example, the control system may be integral to the power electronics used in the operation of the vehicle. Alternatively, the control system may be embedded in the vehicle supervisory controller (VSC), as this would ensure that the parameters may be overwritten if necessary.

The control system comprises: means for converting 105 kinetic energy associated with the movement of the vehicle to electrical energy; means for monitoring 110 at least one parameter associated with the operation of the vehicle; and means for distributing 115 the regenerated electrical energy to at least one subsystem associated with the vehicle. The distribution of regenerated electrical energy depends on data associated with the monitored parameter(s) or stored in the memory of a processing unit.

Each of the components of the control system will be described in detail using Figures 2 to 4.

The data used by the control system can be obtained by monitoring a parameter, for example a state of charge of the battery, or by a signal from a sensor, for example a sensor that detects the speed of the vehicle. Alternatively, the data may be stored on a memory storage means.

Further, the regenerated electrical energy can be directed to the subsystems that require the energy given the current properties of the vehicle. The control system can determine to which subsystems the regenerated energy goes. The determination may be based on rules or criteria. These rules/criteria may be, for example, for the purposes of efficiency and/or providing optimal operating conditions of one of more vehicle systems. In one example the criteria used may be those concerned with the optimum vehicle conditions required for the vehicle to respond to an expected acceleration of the vehicle.

The control system can be run self-sufficiently; i.e. it makes a decision regarding which subsystems to distribute the electrical energy to without requiring user input. This improves the user experience by making the use of subsystems in the vehicle more convenient and timely.

Figure 2 shows a block diagram of the control system 100, as shown in Figure 1 where like reference numerals represent like features. Figure 2 indicates components of the means for converting 105 kinetic energy associated with the movement of the vehicle to electrical energy.

The means for converting 105 kinetic energy associated with the movement of the vehicle to electrical energy may comprise means for stopping 120 the flow of electrical energy associated with the movement of the vehicle to one or more subsystems associated with the vehicle. For example, when the vehicle is braking or decelerating, the flow of electrical energy from the battery of the vehicle to the drive unit may be stopped by opening the electronic circuit. This means may be, for example an electrical or mechanical switch.

The means for converting 105 kinetic energy may comprise a means for using 125 the kinetic energy and momentum of the movement of the vehicle to make the wheels turn the electrical motor. The electric motor may act like a generator by converting the kinetic energy into electrical energy. The regenerated electrical energy is then available to be used in any subsystem of the vehicle that may require it.

In use, when a vehicle is braking or decelerating, one or more subsystems of the vehicle may not require electrical energy from the battery of the vehicle and thus the flow of electrical energy to the subsystem(s) would be stopped. Kinetic energy associated with the movement of the vehicle, for example the wheels, may be provided to an electrical motor. The kinetic energy would then be converted into electrical energy.

An advantage of the conversion of kinetic energy associated with the movement of the vehicle to electrical energy minimises energy losses in the vehicle and, therefore, improves the energy efficiency of the vehicle.

Figure 3 shows a block diagram of the control system 100, as shown in Figure 2 where like reference numerals represent like features. This figure further indicates components of the means for monitoring 110 at least one parameter associated with the operation of the vehicle.

The parameter may be, for example, the vehicle condition, the battery condition, or the temperature of a component or subsystem of the vehicle.

The means for monitoring 110 may comprise one or more sensors for monitoring the vehicle condition 135. The vehicle condition may comprise the motion status or occupancy status. For example, the vehicle may be stationary, unoccupied and parked or it may be stationary, occupied and in traffic congestion. The vehicle may be moving at a steady state velocity on a zero or positive (uphill) gradient. Alternatively the vehicle may be moving at a steady state velocity on a negative (downhill) gradient.

The means for monitoring 110 may also comprise a means for monitoring the charge state 140 of a battery. For example, a ‘high’ state of charge may mean close to or equal to 100% and a ‘low’ state of charge may mean close to or equal to 0%.

The means for monitoring 110 may also comprise one or more electronic sensors for monitoring the battery charge mode 145. The battery may be in charge-depleting mode, which means that the operation of the vehicle is dependent on energy from the battery. For example, if the vehicle is in motion, energy is depleted from the battery to operate the movement of the vehicle. If the vehicle is stationary and occupied, energy may be depleted from the battery for the vehicle’s ancillary power requirements such as, for example, lights, an instrument panel or air conditioning. The battery charge mode may be ‘low rate’ or ‘high rate’. Low charge rates and high charge rates refer to the charging power placed into the battery and may be dependent on the state of charge of the battery. For example, if the battery of a vehicle has a low state of charge, the user may choose to use a high rate battery charge mode in order to increase the total battery range quickly. Charge rates may be relative to the type of battery system adopted in the vehicle. If the vehicle is stationary and parked, a charger may be connected to the vehicle. The operator may be in the vicinity of the vehicle, for example prior to unplugging the charge device. Alternatively, there may be a wireless charging pad at the location. For example, a wireless charging pad may be placed under the vehicle or embedded into a parking bay so that when the pad is aligned with a receiver on the vehicle, induction charging from the pad to the vehicle’s electrical system begins. Alternatively, the vehicle may have been parked after use. It is understood that the location is not limited to the operator’s home address or place of work.

The means for monitoring 110 may also comprise a temperature sensor for monitoring the lubricant temperature 150. The lubricant temperature 150 may be Operating’, low’ or ‘high’. An operating temperature may be defined as a temperature equal to the ideal operating temperature or temperature range of the lubricant of the vehicle being used. A low lubricant temperature may be defined as a temperature lower than the operating temperature or temperature range. A high lubricant temperature may be defined as a temperature higher than the operating temperature or temperature range.

The vehicle condition 135, the charge state 140 of a battery, the battery charge mode 145 and the lubricant temperature 150 are among only some of the parameters that may be monitored by the control system. It is understood that the parameters and the means for monitoring the parameters described above are examples and may comprise other types of parameters such as, for example, the inverter temperature.

The data associated with any one or more of these parameters, or any other parameters that may be monitored by the control system, may be used to make the decision about which subsystem(s) to distribute the energy to. The nature of the decision to distribute electrical energy to the subsystems can be based on a wide range of properties and therefore provide the optimum need and/or the most energy efficient option for the current state of the vehicle.

Figure 4 shows a block diagram of the control system, as shown in Figure 3 where like reference numerals represent like features, according to an embodiment further indicating components of the means for distributing 115 electrical energy converted from kinetic energy of the vehicle to at least one subsystem associated with the vehicle. The distribution is dependent on data associated with one or more parameter.

The subsystem may be, for example, a powertrain 152 of the vehicle which may include a battery 155, an inverter 160, a drive unit 165 and a differential 170. It is to be understood that the term ‘powertrain’ as used herein refers to the combination of a drive train as described above and a torque source, such as an internal combustion engine or an electric motor, or the combination thereof.

The subsystem may be a lubrication circuit 175, which may include a lubricant pump 180 and an arrangement of conduits and valves 185 that distribute the lubricant to the various vehicle components, such as the vehicle’s transmission system, that require it.

Examples of the operation of the means for distributing electrical energy will now be described.

The control system may be used to distribute the regenerated electrical energy to one or more components of the lubricant circuit. In this example, the control system would control the pumping and distribution of lubricant to provide sufficient lubrication to components of the vehicle that may require it. When the control system distributes electrical energy to the lubrication circuit, one of two pump modes may be activated in use: a first pump mode comprising a pre-determined lubricant flow rate or a second pump mode comprising a lubricant flow rate that is higher than the pre-determined lubricant flow rate. The pre-determined lubricant flow rate may be associated with an efficient lubricant flow rate for maintaining an optimum lubricant temperature in accordance with one or more requirements of the vehicle.

For example, in the first pump mode, the flow rate will be at a minimum, set by component durability requirements (e.g. no degradation in life over the current state of the art). Where the lubricant provides a cooling function, the flow may relate to the durability via component temperature. The first pump mode may also be known as the optimum pump mode or optimum lubrication pump mode.

In the second pump mode, the flow rate of the lubricant may be close to the maximum flow potential of the system. This flow may be distributed accordingly within the system but the rate will be high. The second pump mode may also be known as the high pump mode or high lubrication pump mode.

Over-lubrication would increase the drag losses within the system, thereby warming the system up and providing longer term aggregate efficiency benefits.

The selection of the pump mode in dependence on the current state of the vehicle allows the lubricant to be pumped at the most suitable flow rate and in turn allows the lubricant temperature to be maintained. Flow rate optimisation may be speed-specific, torquespecific or temperature-specific, for a given hardware and lubricant combination. The flow rate may be controlled by a processor receiving one or more signals from one or more sensors configured to monitor torque, vehicle speed or temperature (wherein the temperature measured may be any of the temperature of the lubricant or temperature of any other portion of the vehicle engine or transmission system). The processor uses the received signals to determine an output signal for controlling the flow rate, for example a signal for controlling a lubrication pump. The determination may use other data in addition to or in the alternative to the sensor data, such as, for example, data stored on a memory means that provides a flow rate profile and/or one or more thresholds to compare the sensor signal to. The flow rate profile may require a plurality of different sensor signals to determine the output signal. For example both temperature and speed sensor signals may be used to determine the output signal.

For example, a scenario in which the current battery charge state 140 is high (close to or at 100%), and if the battery 155 is in charge-depleting mode (vehicle operation is dependent on energy from the battery 155), and the lubricant temperature is detected as low (defined as below the ideal operating temperature for the vehicle component architecture), would cause the control system to distribute energy to the lubrication system and activate the first pump mode.

When the first pump mode is activated, a suitable lubricant flow rate is used to pump lubricant to the vehicle components, such that maximum efficiency and durability are achieved with respect to the exact vehicle operating conditions during that time. In the example above, a relatively low flow rate would be used to improve the energy efficiency at low temperatures.

In contrast, a scenario in which the current battery charge is high (close to or at 100%), and if the battery is in charge-depleting mode (vehicle operation is dependent on energy from the battery), and the lubricant temperature is detected as high (defined as above the ideal operating temperature for the vehicle component architecture), would cause the control system to distribute energy to the lubrication system and activate the second pump mode. In the second pump mode, a high flow rate, which may be close to the maximum flow potential of the system, is used.

The data used by the control system to distribute the electrical energy may be signals from a number of sensors. For example, a sensor can be used to detect temperature, speed, torque and any other driving condition. The nature of the decision to distribute electrical energy to the subsystems can be based on a wide range of factors. This enables the optimum use of energy by providing the energy to the subsystems that require it the most in the current state of the vehicle. Different sensors may be used, including sensors utilising electronic or optoelectronic technology.

The data may be associated with one or more criteria. The data may also be stored on a memory storage means or memory means, for example an electronic memory such as RAM, ROM, solid state memory, a hard drive or other electronic memory device. The advantage of this is that the data would not have to be obtained when required. For example, the memory storage means may store a default distribution profile or sequence that may be used if or when data from the monitored parameters are not available. The availability of the data in the memory storage means may also enable the control system to make a faster decision for distributing the electrical energy.

The decision to distribute electrical energy to one or more subsystems may be established using processing means such as, but not limited to, an electronic processor or ECU.

The processing means may comprise a data input means and one or more models or rules. Given data as input, the models/rules determine where the electrical energy should be distributed to. The data is received by the processing means and compared to the models or rules. The processing means is configured to instruct the distribution of energy to one or more subsystems based on the comparison of the data to the models or rules.

The processing means may comprise a priority list. The priority list may comprise a rule that defines a default energy distribution to one or more subsystems, for example to the battery. The default energy distribution may be overridden given certain inputs in the priority list, for example, temperature data from a sensor.

An advantage of the energy distribution means is that the regenerated electrical energy may be distributed to one or more components of the powertrain of the vehicle, such as the battery, the inverter, the drive unit(s) and/or the differential. In addition, the electrical energy may be distributed to one or more components of the lubricant circuit. The lubricant pumping means and the arrangement of conduits and valves can enable the controlled pumping and distribution of lubricant to provide sufficient lubrication to components of the vehicle that require it.

The subsystem may also be a battery cooling means and a battery heating means for adjusting the temperature of the battery. The subsystem may also be an inverter cooling means, a stator cooling water system or a cooling generator.

Advantageously, the regenerated electrical energy can be used to control the temperature of the battery to maximise energy efficiency and minimise energy loss in the vehicle.

The distribution of electrical energy is dependent on data. The data used by the control system may be, for example, signals from a number of sensors. A sensor may be used to detect temperature, speed, torque and any other driving condition. The means for distributing electrical energy may be dependent on a signal associated with, for example, a charge state 140 of a battery or a charge mode of a battery. Other signals may be used for the distribution of energy such as a temperature of a component of the vehicle or a property associated with the movement of the vehicle, such as a velocity of the vehicle.

It is understood that the signals on which the distribution of electrical energy are in dependence on, as described above, are examples and may comprise other signals such as, for example, temperature of the vehicle battery or torque of the vehicle.

The data may be associated with one or more criteria and stored on a memory storage means.

Figure 5 shows a schematic diagram of a vehicle 500 indicating numerous components of the vehicle according to an embodiment. In this example, the vehicle is an electric car. The vehicle 500 comprises a chassis 505 that supports propulsion battery modules 510, inverter and power electronics 515, a rear axle electric drive unit and gear train 520, two front wheels 525 and two rear wheels 530. Propulsion battery modules 510 may be the energy storage devices used to provide energy to the vehicle propulsion system and other electrical ancillaries. Inverter electronics may convert the direct current (DC) voltage from the battery modules to alternating current (AC) voltage for the propulsion motors. The power electronics may then demand power from the battery modules based on the vehicle driving condition and distribute the power to high voltage transfer cables. The rear axle electric drive unit and gear train 520 is effectively a propulsion electric motor designed to provide power to the rear wheels of the vehicle. Within the unit, there is a gear train that converts the motor rotational power into rotational power of the differential, where the differential is part of the gear train. The gear train may also act as a torque control device such that motor torque can be translated to the axle shafts in the correct plane and at a suitable magnitude. For instance, wheel speeds are typically lower than motor speeds and so the gear train steps the speeds and torques to suitable levels, through gearing.

The vehicle also comprises a front axle shaft 535 and a rear axle shaft 540. Reference to the rear axle electric drive unit and gear train 520 is hereinafter described as the rear axle electric drive unit 520.

In this example, the vehicle is a two wheel drive vehicle and thereby the two rear wheels 530 are driven wheels. It is understood that the control system 100 may be implemented in a four wheel drive electric vehicle. A four wheel drive electric vehicle may use more than one electric drive unit, for example one for each axle of the vehicle. Alternatively the four wheel drive electric vehicle may comprise a mechanical differential between the front and rear axles. Many architectural layouts may be adopted for different types of vehicles and are not limited to those described herein.

When the vehicle 500 is in motion and/or accelerating, electrical energy from the propulsion battery modules 510 is converted into kinetic energy using the inverter and power electronics 515 and rear axle electric drive unit and gear train 520. The invertor may convert DC voltage supplied from the battery to AC voltage for supply to the rear axle electric drive unit which comprises an electric motor for converting the electrical energy supplied from the invertor to kinetic energy for supply to the wheels. The kinetic energy is then used to drive the two rear wheels 530. In other words, energy is depleted from the battery to operate the movement of the vehicle. Electrical energy from the battery may also be used for the vehicle’s power requirements such as, for example, lights, an instrument panel, air conditioning or lubrication.

Figure 6 shows a schematic diagram of a vehicle 600 comprising a control system 605, according to an embodiment. Like reference numerals incremented by 100 are used in figure 6 to refer to like features in figure 5.

In this embodiment, the vehicle 600 is braking and decelerating. Upon braking and/or deceleration, the flow of electrical energy from the battery of the vehicle to the drive unit is stopped 120 by opening the electronic circuit. The kinetic energy 645 associated with the movement of the wheels 630 is provided to the gear train within the rear axle electric drive unit, subsequently spinning the rotor in the electrical machine. The machine can be used as a generator in this instance. The kinetic energy is thus converted into electrical energy. The regenerated electrical energy is then available to be used in any subsystem of the vehicle that may require it.

In this embodiment the control system 605 is located towards the front of the vehicle. The control system may be located at any location on the vehicle.

The parameters monitored by the control system 605 in this example will now be described. The vehicle is on a positive (uphill) gradient. The battery charge level is low and the battery is in charge-depleting mode. The lubricant temperature is determined as being low with respect to the ideal operating temperature or temperature range for the lubricant and component of the vehicle being used. Data associated with the above parameters are used by the control system to make the decision about which subsystem(s) to distribute the regenerated electrical energy to.

In this case, the control system distributes electrical energy 650 to the battery 610 and the lubrication circuit 635, via the inverter and power electronics 615. The inverter and power electronics 615 can determine the rate of energy consumption or recovery possible. The inverter may specify the conversion rate and efficiency from DC to AC or vice versa. The inverter and power electronics would have power and thermal limitation, which would influence the total electrical power flow that the system can sustain and peak at. The control system controls the pumping and distribution of lubricant to provide sufficient lubrication to components of the vehicle. When the control system distributes electrical energy to the lubrication circuit, the first pump mode is activated to provide lubrication to the components of the rear axle electric drive unit and gear train 620. This allows the lubricant to be pumped at an optimum flow rate 640, allowing the lubricant temperature to be maintained whilst minimising the electrical energy consumed. A suitable lubricant flow rate is used such that the maximum efficiency and durability are achieved with respect to the exact vehicle operating conditions during that time. This may involve continuous flow, zero flow or a pulsed flow. The control system would determine the most energy efficient approach whilst respecting durability requirements. In the example above, a relatively low flow rate would be used to improve the energy efficiency at low temperatures.

The features of this embodiment may also apply when the vehicle is decelerating without braking. The kinetic energy may be harvested from the movement of the two rear wheels 630, the two front wheels 625 or all four wheels 625, 630.

Advantageously, when the vehicle is braking and decelerating, the conversion of kinetic energy from the wheels to electrical energy enables the kinetic energy to be harvested and utilised in the vehicle. The kinetic energy would otherwise be lost and thus the above embodiment demonstrates the ability of the control system 605 to minimise energy losses in the vehicle by directing the energy to where it is required. In this particular embodiment the lubricant temperature is maintained without depleting further charge from the battery, which is already at a low battery charge level.

Figure 7 shows a schematic diagram of a vehicle 700 comprising a control system 705, according to an embodiment of the invention. Like reference numerals incremented by 100 are used in figure 7 to refer to like features in figure 6.

In this embodiment, the vehicle 700 is braking and decelerating. Upon braking and/or deceleration, the flow of electrical energy from the battery 710 of the vehicle to the drive unit is stopped 120 by opening the electronic circuit. The kinetic energy 745 associated with the movement of the wheels 730 is used to drive the electric motor in the rear axle electric drive unit via the gear train which converts the kinetic energy into electrical energy. The regenerated electrical energy is then available to be used in any subsystem of the vehicle that may require it.

The parameters monitored by the control system 705 in this example will now be described. The vehicle is on a positive (uphill) gradient. The battery charge level is high and the battery is in charge-depleting mode. The lubricant temperature is determined as being high with respect to the ideal operating temperature or temperature range for the lubricant and component of the vehicle being used.

Data associated with the above parameters are used by the control system 705 to make the decision about which subsystem(s) to distribute the regenerated electrical energy to.

The data associated with the battery, the motion status of the vehicle and temperature of the lubricant is inputted into the control system 705. A processor compares the data or one or more models or rules and instructs the distribution of regenerated electrical energy 750 to the lubrication circuit 735. The control system 705 controls the pumping and distribution of lubricant to provide sufficient lubrication to components of the vehicle. When the control system 705 distributes electrical energy to the lubrication circuit, the first pump mode is activated to provide lubrication to the rear axle electric drive unit and gear train 720. This allows the lubricant to be pumped at a flow rate 740 that enables the heat energy to be carried away by the oil and the optimum lubricant temperature to be maintained. The most efficient flow rate is determined based on the current temperature, speed and load to ensure that maximum efficiency and durability are achieved. Since the battery charge level is high, the control system determines that there is a sufficient amount of electrical energy to pump lubricant at a high flow rate and to provide electrical energy to other subsystems of the vehicle that may require it. A suitable lubricant flow rate is used such that the maximum efficiency and durability are achieved with respect to the exact vehicle operating conditions during that time. In this case, the first pump mode would be used based on a thermally dependent control parameter within the flow rate decision logic. This would minimise any further temperature rise, without component neglect.

An alternative to a high flow rate may be to flow at the minimum rate to provide sufficient lubrication without adding too much heat to the high temperature lubricant. This would maximise efficiency and durability.

There may be other situations in which a high flow rate may be beneficial such as, for example, where the lubricant is flowing across a device or area of high thermal energy transfer.

Advantageously, when the vehicle is braking and decelerating, the conversion of kinetic energy from the wheels to electrical energy enables the kinetic energy to be harvested and utilised in the vehicle. The kinetic energy would otherwise be lost and thus the above embodiment demonstrates the ability of the control system 705 to minimise energy losses in the vehicle by directing the energy to where it is required. For example, when the battery charge level is high, the regenerated electrical energy may be used to control both the lubricant temperature and the temperature of the battery to maximise efficiency and minimise energy loss.

Many modifications may be made to the above examples without departing from the 5 scope of the present invention as defined in the accompanying claims. In particular it is noted that none of the embodiments are mutually exclusive and the various embodiments of the control system and vehicle may be combined together in any suitable combination.

Claims

1. A control system for a vehicle comprising:

means for converting kinetic energy associated with the movement of the vehicle to electrical energy;

means for monitoring at least one parameter associated with the operation of the vehicle;

means for distributing electrical energy converted from kinetic energy of the vehicle between: the means for converting kinetic energy associated with the movement of the vehicle to electrical energy and an energy storage device of the vehicle, and the means for converting kinetic energy associated with the movement of the vehicle to electrical energy and at least one further component associated with the vehicle in dependence on data associated with the at least one parameter; wherein the at least one further component comprises at least one of: a component of a lubrication circuit, a heating or cooling means of the energy storage device, and a heating or cooling means of a component of a drive train.

2. The control system of any preceding claim, wherein the means for distributing electrical energy distributes electrical energy in dependence on a signal associated with a charge state of a battery.

3. The control system of any preceding claim, wherein the means for distributing electrical energy distributes electrical energy in dependence on a signal associated with a charge mode of a battery.

4. The control system of any preceding claim, wherein the means for distributing electrical energy distributes electrical energy in dependence on a signal associated with a temperature of a lubricant.

5. The control system of any preceding claim, wherein electrical energy is distributed to the component of a lubrication circuit and one of two pump modes is activated in use:

a first pump mode comprising a pre-determined lubricant flow rate; or a second pump mode comprising a lubricant flow rate that is higher than the predetermined lubricant flow rate, wherein the pre-determined lubricant flow rate is a pre-determined minimum flow rate that provides sufficient lubrication of components provided with lubricant by the lubricant circuit.

6. The control system of any preceding claim, wherein the parameter associated with the operation of the vehicle comprises any one or more of: state of charge of a battery, battery charge mode, lubricant temperature or inverter temperature.

7. The control system of any preceding claim, wherein the data is associated with signals from at least one sensor.

8. The control system of any preceding claim, wherein the data is associated with one or more criteria and is stored on memory storage means.

9. The control system of any preceding claim, wherein the data is associated with one or more models stored on a memory storage means, the model being executed using a processing means.

10. A control method for a vehicle comprising:

converting kinetic energy associated with the movement of the vehicle to electrical energy;

monitoring at least one parameter associated with the operation of the vehicle; and distributing electrical energy converted from kinetic energy of the vehicle between: a means for converting kinetic energy associated with the movement of the vehicle to electrical energy and an energy storage device of the vehicle, and the means for converting kinetic energy associated with the movement of the vehicle to electrical energy and at least one further component associated with the vehicle in dependence on data associated with the at least one parameter; wherein the at least one further component comprises at least one of: a component of a lubrication circuit, a heating or cooling means of the energy storage device, and a heating or cooling means of a component of a drive train.

11. The control method of Claim 10, wherein electrical energy is distributed in dependence on a signal associated with a charge state of a battery.

12. The control method of Claim 10 or 11, wherein electrical energy is distributed in dependence on a signal associated with a charge mode of a battery.

13. The control method of any of Claims 10 to 12, wherein electrical energy is distributed in dependence on a signal associated with a temperature of a lubricant.

14. The control method of any of Claims 10 to 13, wherein electrical energy is distributed to the component of a lubrication circuit and one of two pump modes is activated in use:

15. The control method of any of Claims 10 to 14, wherein the parameter associated with the operation of the vehicle comprises any one or more of: state of charge of a battery, battery charge mode, lubricant temperature or inverter temperature.

16. The control method of Claim 15, wherein the first pump mode is activated in response to the battery charge mode being in depletion mode and lubricant temperature being lower than a predetermined operating temperature.

17. The control method of Claim 15, wherein the second pump mode is activated in response to the battery charge mode being in depletion mode and lubricant temperature being higher than a predetermined operating temperature.

18. The control method of any of Claims 10 to 17, wherein the data is associated with signals from at least one sensor.

19. The control method of any of Claims 10 to 18, wherein the data is associated with one or more criteria and is stored on memory storage means.

20. The control method of any of Claims 10 to 19, wherein the data is associated with 5 one or more models stored on a memory storage means, the model being executed using a processing means.

21. A vehicle comprising a control system as claimed in any one of claims 1 to 9.