Patent Description:
Heavy-duty vehicles are designed to carry heavy loads, sometimes hazardous goods, and often on public roads. They are therefore associated with stricter safety requirements compared to, e.g., regular passenger cars. Rigorous pre-launch procedures are often required to be performed by a driver or technician before the vehicle is allowed to be put into motion. Some drivers are reluctant to turn off their vehicles during periods of inactivity since these time-consuming pre-launch procedures then need to be repeated once the vehicle is started up again.

Many drivers also leave their motors running when the vehicle is stationary since this way the cab temperature is maintained even in cold climates, and the batteries of the vehicle are not exhausted. The motor is often also kept running in hot climates to keep air-conditioning (AC) going and the temperature in cold storage compartments sufficiently low. However, this is an energy inefficient way to operate a heavy-duty vehicle, and therefore undesired.

<CIT> describes an engine control system which is configured to automatically start a combustion engine in response to a number of enabler signals indicative of, e.g., low battery voltage, low cab temperature and/or low engine temperature. This allows a driver to turn off the engine without worrying for, e.g., the cab temperature dropping too low and the battery voltage running low. However, further improvement in energy efficient vehicle control is desired.

<CIT> discloses a system for reducing the idling time of a vehicle, where the system is arranged to start an engine of the vehicle if certain conditions are met, such as low battery voltage or low engine temperature.

It is an object of the present invention to provide techniques which improve energy efficiency in heavy-duty vehicles. This object is at least in part obtained by a control unit for a heavy-duty vehicle. The control unit is arranged to control the vehicle according to a mode of operation selected from at least three different modes of operation, where the mode of operation is configurable by a driver via a mode selection device. A first mode of operation is a mode of operation where the vehicle is in an inactivated state, i.e., turned off. A second mode of operation is a stand-by mode of operation where the vehicle is in an active state, and where the control unit is arranged to turn off a combustion engine of the vehicle in case a vehicle state meets a pre-determined power-down criterion. This mode of operation is an introduced mode of operation where the vehicle is deemed active from many sub-systems, such as cab temperature control and the like, but where the engine is turned off by the vehicle control system in case it is not needed. A third mode of operation is a mode of operation where the vehicle is in the active state, and wherein the third mode of operation corresponds to a non-stand-by regular active state of the vehicle. In this state the vehicle may enter into a state of motion, i.e., accelerate into motion. The control unit is configured to require manual input from a driver prior to transitioning into the third mode of operation from the second mode of operation. This increases overall vehicle safety, since it reduces the chance of involuntarily entering the third mode of operation where the vehicle may be brought into motion.

This way the drawbacks of turning of the ignition during periods of inactivity are largely eliminated, since the driver will not experience any loss of function due to placing the vehicle in the second mode of operation compared to leaving the vehicle in the third mode of operation where the engine is running. The driver is thus more likely to voluntarily place the vehicle in the second mode of operation compared to turning off the engine of a legacy heavy-duty vehicle.

According to aspects, the control unit is required to successfully execute a pre-launch procedure prior to entering the second mode of operation or the third mode of operation from the first mode of operation. This pre-launch procedure may involve, e.g., technical verifications of vehicle system functions, driver authentication of various forms such as a verification of driver credentials and/or driver authorization, and potentially also alcohol tests of the driver. Notably, the pre-launch procedure is required when transiting from the first mode to the second and third mode, not when entering the third mode of operation from the second mode of operation. , the control unit is arranged to transition between the second mode of operation and the third mode of operation without successfully executing the pre-launch procedure.

According to aspects, the vehicle is required to be in a stationary state when in the second mode of operation. Being in a stationary state means that vehicle wheels are not moving. This may be ensured by, e.g., activating service brakes and/or parking brakes of the vehicle. Being in a stationary state optionally also comprises any auxiliary equipment being inactivated, such as a crane not being used.

According to aspects, the control unit is arranged to inactivate a vehicle motion management (VMM) function when in the second mode of operation. Computational functions such as vehicle motion management normally consume a significant amount of electrical energy. By inactivating such signal processing functions, or at least parts of such functions, energy consumption by the vehicle is reduced. The circuitry of the signal processing units may be placed in sleep mode when the vehicle is in the second mode of operation, where the sleep mode is an energy conserving mode of operation of the circuitry.

According to aspects, the control unit is configured to automatically transition into the second mode of operation from the third mode of operation in case the vehicle has been stationary for a pre-determined period of time. This means that even vehicles operated by drivers that are reluctant to place the vehicle in the second mode of operation will eventually transition into the second mode of operation, which is an advantage.

According to aspects, the pre-determined power-down criterion comprises any of: cab temperature, electrical energy storage (ESS) state of charge, trailer compartment temperature, and combustion engine temperature. Thus, the control unit will not leave the motor inactive if there is a need for having the motor running by any of the above listed sub-systems, which is an advantage. The driver may place the vehicle in the second mode of operation knowing that important vehicle subsystems will not be affected by the change in mode of operation.

According to aspects, the control unit is arranged to indicate a current mode of operation via an in-cabin display. Thus, the driver easily sees what state the vehicle is in, which is an advantage. The driver also knows the reason for the engine suddenly turning on and off during a period of inactivity.

There is also disclosed herein methods, computer programs, computer readable media, computer program products, and vehicles associated with the above discussed advantages.

The skilled person realizes that different features of the present invention may be combined to create embodiments other than those described in the following, without departing from the scope of the present invention as defined by the appended claims.

<FIG> illustrates a heavy-duty vehicle <NUM>. This particular example comprises a tractor unit <NUM> which is arranged to tow a trailer unit <NUM>. The tractor <NUM> comprises a vehicle control unit (ECU) <NUM> arranged to control various functions of the vehicle <NUM>. For instance, the ECU may be arranged to perform a vehicle motion management (VMM) function comprising control of wheel slip, vehicle unit stability, and so on. The ECU may be communicatively coupled, e.g., via wireless link, to a remote server <NUM>. This remote server may be arranged to perform various configurations of the ECU, and to provide various forms of data to the ECU <NUM>.

In order to start the vehicle <NUM>, a driver may need to perform certain pre-launch tasks, such as verifying different technical functions on the vehicle, and perhaps disengaging an alcohol interlock device. An alcohol interlock device is a device which requires the driver to blow into a mouthpiece on the device before starting or continuing to operate the vehicle. If the resultant breath-alcohol concentration analyzed result is greater than the programmed blood alcohol concentration (which varies between countries), the device prevents the engine of the vehicle <NUM> from being started, thus immobilizing the vehicle.

In cold climates, the drivers have a tendency to leave the motor running during periods of inactivity when the vehicle is stationary, e.g., waiting for cargo to be loaded waiting in queue or to embark on a ferry. This is done in order to prevent a temperature drop inside the cab, and/or a discharge of the battery. Also, if the ambient temperature is very low, it may be hard to start the engine again if its temperature has gone critically low.

The same holds true for vehicles operating in hot climates, where drivers have a tendency to leave the motor running in order to keep the AC operational, and to keep the temperature in cold storage compartments at the required temperature.

A situation where drivers leave the engine running during periods of inactivity when the vehicle is stationary is undesired, for both environmental as well as energy efficiency and cost efficiency reasons. A purpose of the present invention is to present a system which allows the drivers to "turn off" the vehicle without the vehicle leaving an active mode of operation. Thus, there is a reduced incentive for the drivers to leave their motors running during periods of inactivity. A benefit of the techniques disclosed herein is a reduced energy consumption.

The present invention describes a vehicle control system which encourages drivers to place the vehicle in a type of stand-by mode of operation, where the vehicle is considered as being in an active state of operation, but where the ECU <NUM> is allowed to turn off the engine and other systems if certain vehicle state criteria are fulfilled. Since the vehicle is considered to be in an active state, there is no requirement to perform the pre-launch procedures when exiting the stand-by mode of operation.

<FIG> illustrates a mode selection device <NUM> connected to the ECU <NUM> of the vehicle <NUM>. This mode selection device is a manual control device which the driver can use to configure a mode of operation of the vehicle into one out of a plurality of modes of operation. The mode selection device may be realized by a control knob or button, e.g., as a start button or ignition key, but with an extra mode of operation indicating a stand-by mode of operation. In this stand-by mode of operation, the vehicle control system is active. However, it is operating with reduced functionality, and the ECU is allowed to turn off the engine <NUM> in case the vehicle state meets a set of pre-determined criteria <NUM>, such as if the battery is sufficiently charged, and the temperatures of the vehicle can be kept within acceptable levels without the engine running.

The ECU is optionally also allowed to deactivate other vehicle systems when operating in the stand-by mode of operation. For instance, the ECU may deactivate the VMM function comprising computationally intensive functions such as vehicle motion estimation, vehicle motion control functions, and vehicle motion prediction. Other functions such as various communications functions are preferably maintained, such as the communication link to the remote server <NUM>. The vehicle sensor systems <NUM> and energy management systems <NUM> are preferably also kept on-line, at least in part since these systems may be required to be active also during periods of inactivity when the vehicle is stationary. Also, it may take some time to start up these systems and verify full functionality before setting the vehicle into motion.

<FIG> illustrates an example control unit <NUM> for a heavy-duty vehicle such as the vehicle <NUM>, which may be comprised as a part of the ECU <NUM>. The control unit <NUM> is arranged to control the vehicle according to a mode of operation selected from at least three different modes of operation, where the currently active mode of operation is configurable by a driver via the mode selection device <NUM>. A first mode of operation <NUM> is a mode of operation where the vehicle is in an inactivated state, i.e., when the vehicle is turned off or otherwise fully inactivated. This mode of operation can be entered into, e.g., when the vehicle is parked for an extended time duration. A second mode of operation <NUM> is the above-mentioned stand-by mode of operation where the vehicle is in an active state <NUM>, and where the control unit <NUM> is arranged to turn off a combustion engine <NUM> of the vehicle <NUM> in case a vehicle state meets a pre-determined power-down criterion <NUM>. Some example pre-determined power-down criteria is listed in <CIT>. The power-down criteria may be configured at the factory, or via software update, possibly via the wireless link to the remote server <NUM>. A third mode of operation <NUM> is a mode of operation where the vehicle <NUM> is in the active state, i.e., in this state the vehicle may be put in motion, and the VMM function (if present) is active. This mode corresponds to the regular active state of a vehicle.

An example <NUM> of the mode selection device <NUM> is illustrated in <FIG>. This example mode selection device comprises a knob or ignition key arrangement which can be set in three different configurations, one configuration corresponds to turning the vehicle off (OFF), one configuration corresponds to turning the vehicle on (ON), and one configuration corresponds to placing the vehicle in the stand-by mode of operation (STAND-BY). Other example mode selection devices may comprise touchscreens, voice command, or other input options.

Optionally, as indicated in <FIG>, the control unit <NUM>, <NUM> is required to successfully execute a pre-launch procedure <NUM> prior to entering <NUM> into the second mode of operation <NUM> or the third mode of operation <NUM>, i.e., the active state. The pre-launch procedure <NUM> may, e.g., comprise a verification of driver credentials and/or driver authorization, such as an identification check and/or an alcohol interlock system. The pre-launch procedure <NUM> may also comprise a verification of technical vehicle systems function <NUM>, which may be annoyingly time consuming in some cases.

A driver of the vehicle <NUM> contemplating leaving the vehicle running in order to, e.g., avoid having to redo a pre-launch procedure or experience a temperature drop in the cabin, can now instead place the vehicle in the stand-by mode of operation which, essentially, is the same thing as leaving the motor running. Thus, there is much less incentive in leaving the motor running since the stand-by state has most of the properties of the third mode of operation but is a much more energy efficient and environmentally friendly mode of operation.

According to some aspects, the control unit <NUM>, <NUM> is arranged to transition <NUM> between the second mode of operation <NUM> and the third mode of operation <NUM> without requiring successful execution of the pre-launch procedure <NUM>. Thus, a driver may freely configure the vehicle in the second mode of operation (stand-by), and then back to the third mode of operation (fully operational mode), without having to execute any of the pre-lunch procedures that may be required when transitioning from the first mode of operation <NUM> into the second or third mode of operation, i.e., the active state <NUM>.

The stand-by mode of operation may be associated with constraints on vehicle state. This means that the stand-by mode of operation will optionally only be available under certain circumstances. For instance, the stand-by mode of operation may only be allowed if the vehicle <NUM> is in a stationary state where the vehicle is not moving relative to the ground, perhaps with an engaged parking brake, or where position sensors indicate that the vehicle is truly stationary.

The VMM functionality mentioned above may involve rather complex computations involving powerful processing units. Such signal processing operations may consume significant amounts of energy, i.e., draw significant amounts of current from the vehicle electrical energy storage system (ESS). Vehicle energy efficiency can be further improved if the VMM function, or parts of the VMM function, are inactivated when the ECU <NUM> controls the vehicle according to the second mode of operation, i.e., the stand-by mode of operation. In other words, the control unit <NUM>, <NUM> is optionally arranged to inactivate a VMM function of the vehicle <NUM>, or parts of theVMM function, when the vehicle is controlled in the second mode of operation <NUM>.

Advantageously, the VMM function <NUM> may be arranged to trigger a software update procedure when the vehicle is in the second mode of operation. This is an advantage since the VMM has time to perform the software update, and it may consume energy since the control unit will turn the engine back on in case ESS state of charge reaches too low levels. The vehicle may be prevented from immediately entering into the third mode of operation from the second mode of operation until the software update has been completed. Thus, it may be preferred to only execute minor software updates and downloads of data in this manner.

The control unit may optionally also be configured to automatically transition the vehicle operation into the second mode of operation from the third mode of operation in case the vehicle has been stationary for a pre-determined period of time. Thus, if the driver still leaves the engine running for an extended period of time despite the vehicle being inactive and stationary, then the control unit may automatically, and without driver input, transition the vehicle control into the second mode of operation. This transition may be conditioned on the vehicle not being located in vicinity of some given type of environment such as in the middle of a road or the like. The transition should of course also be prevented in case some auxiliary equipment is in use, like a crane, unless this operation is deemed supportable by the charge in the ESS. The control unit <NUM>, <NUM> may further be configured to require manual input from a driver prior to transitioning into the third mode of operation from the second mode of operation. Thus, if the driver keeps the vehicle <NUM> stationary for enough time, such that the control unit automatically transfers vehicle control into the second mode of operation, the vehicle may request driver input via the mode selection device <NUM> before the vehicle is allowed to transition into the third mode of operation and be put into motion again.

As discussed at length in <CIT>, the pre-determined power-down criterion optionally comprises any of: cab temperature, electrical energy storage (ESS) state of charge, trailer compartment temperature, and combustion engine temperature.

<FIG> schematically illustrates an in-cabin display, such as a dashboard display. The control unit <NUM>, <NUM> is arranged to indicate the current mode of operation <NUM> via the in-cabin display <NUM>.

<FIG> is a flow chart illustrating methods which summarize the above discussions. There is illustrated a computer implemented method, performed by a control unit <NUM>, <NUM> arranged to control a heavy-duty vehicle <NUM> according to a mode of operation selected from at least three different modes of operation. The method comprises defining S1 a first mode of operation <NUM> as a mode of operation where the vehicle is in an inactivated state, defining S2 a second mode of operation <NUM> as a stand-by mode of operation where the vehicle is in an active state <NUM>, and where the control unit <NUM>, <NUM> is arranged to turn off a combustion engine of the vehicle <NUM> in case a vehicle state meets a pre-determined power-down criterion, defining S3 a third mode of operation <NUM> as a mode of operation where the vehicle <NUM> is in the active state, and configuring S3 the mode of operation based on driver input via a mode selection device <NUM>, <NUM>.

<FIG> schematically illustrates, in terms of a number of functional units, the components of a control unit <NUM> according to embodiments of the discussions herein, such as the ECU <NUM>. This control unit <NUM> may be comprised in the articulated vehicle <NUM>. Processing circuitry <NUM> is provided using any combination of one or more of a suitable central processing unit CPU, multiprocessor, microcontroller, digital signal processor DSP, etc., capable of executing software instructions stored in a computer program product, e.g. in the form of a storage medium <NUM>. The processing circuitry <NUM> may further be provided as at least one application specific integrated circuit ASIC, or field programmable gate array FPGA.

Claim 1:
A control unit (<NUM>, <NUM>) for a heavy-duty vehicle (<NUM>), where the control unit (<NUM>, <NUM>) is arranged to control the vehicle (<NUM>) according to a mode of operation selected from at least three different modes of operation, where the mode of operation is configurable by a driver via a mode selection device (<NUM>, <NUM>),
where a first mode of operation (<NUM>) is a mode of operation where the vehicle is in an inactivated state,
where a second mode of operation (<NUM>) is a stand-by mode of operation where the vehicle is in an active state (<NUM>), and where the control unit (<NUM>, <NUM>) is arranged to turn off a combustion engine of the vehicle (<NUM>) in case a vehicle state meets a pre-determined power-down criterion, and
where a third mode of operation (<NUM>) is a mode of operation where the vehicle (<NUM>) is in the active state, and wherein the third mode of operation (<NUM>) corresponds to a non-stand-by regular active state of the vehicle, and
where the control unit (<NUM>, <NUM>) is configured to require manual input from a driver prior to transitioning into the third mode of operation from the second mode of operation.