Charging method and assembly utilizing a mule vehicle with a storage battery

An exemplary charging method includes charging a storage battery of a mule vehicle as a tow vehicle tows the mule vehicle to a stranded vehicle. The storage battery configured to be electrically coupled to a traction battery of an electrified vehicle to charge the traction battery. An exemplary charging assembly includes a mule vehicle. A storage battery of the mule vehicle charges as the mule vehicle is towed to a stranded vehicle. The storage battery is configured to be electrically coupled to a traction battery of the electrified vehicle to charge the traction battery.

TECHNICAL FIELD

This disclosure relates generally to a mule vehicle having a storage battery used to charge a traction battery of an electrified vehicle. The storage battery of the mule vehicle can be charged as the mule vehicle is towed to the electrified vehicle that is stranded, or another type of stranded vehicle.

BACKGROUND

Electrified vehicles differ from conventional motor vehicles because electrified vehicles are selectively driven using one or more electric machines powered by a traction battery. The electric machines can drive the electrified vehicles instead of, or in addition to, an internal combustion engine. Example electrified vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs).

If an amount of electrical energy held by the traction battery drops below a threshold level, the electrified vehicle may be stranded. That is, the traction battery, when sufficiently depleted, cannot adequately power the electric machines to provide propulsive power to wheels of the electrified vehicle. The traction battery can be recharged by a charging station, but a charging station is not always nearby. Also, the charging station, even if nearby, may be malfunctioning and unable to charge the traction battery.

Conventional vehicles can become stranded as well, due to, for example, a mechanical failure.

SUMMARY

A charging method according to an exemplary aspect of the present disclosure includes, among other things, charging a storage battery of a mule vehicle as a tow vehicle tows the mule vehicle to a stranded vehicle. The storage battery is configured to be electrically coupled to a traction battery of an electrified vehicle to charge the traction battery.

In a further non-limiting embodiment of the foregoing method, the mule vehicle is mechanically coupled to the tow vehicle when the tow vehicle tows the mule vehicle to the stranded vehicle.

A further non-limiting embodiment of any of the foregoing methods includes, after the tow vehicle and the mule vehicle reach the stranded vehicle, mechanically coupling the stranded vehicle to the tow vehicle, and then towing the stranded vehicle with the tow vehicle as the mule vehicle autonomously follows the stranded vehicle.

A further non-limiting embodiment of any of the foregoing methods includes, after the tow vehicle and the mule vehicle reach the stranded vehicle, mechanically coupling the stranded vehicle to the tow vehicle, and then towing the stranded vehicle with the tow vehicle.

A further non-limiting embodiment of any of the foregoing methods includes mechanically coupling the mule vehicle to the stranded vehicle and then using the mule vehicle to assist the towing of the stranded vehicle with the tow vehicle.

A further non-limiting embodiment of any of the foregoing methods includes pushing the stranded vehicle with the mule vehicle to assist the towing of the stranded vehicle with the tow vehicle.

A further non-limiting embodiment of any of the foregoing methods includes braking the mule vehicle to slow the stranded vehicle during the towing and thereby assist the towing of the stranded vehicle with the tow vehicle.

A further non-limiting embodiment of any of the foregoing methods includes towing the stranded vehicle with the tow vehicle as the mule vehicle is driven by an operator located on the mule vehicle.

A further non-limiting embodiment of any of the foregoing methods includes regeneratively charging the storage battery of the mule vehicle when towing the mule vehicle.

A further non-limiting embodiment of any of the foregoing methods includes adjusting the charging based on a distance that the tow vehicle tows the mule vehicle to the electrified vehicle.

A charging assembly according to an exemplary aspect of the present disclosure includes, among other things, a mule vehicle. A storage battery of the mule vehicle charges as the mule vehicle is towed to a stranded vehicle. The storage battery is configured to be electrically coupled to a traction battery of the electrified vehicle to charge the traction battery.

In a further non-limiting embodiment of the foregoing assembly, the storage battery is regeneratively charged when the mule is towed to the electrified vehicle.

In a further non-limiting embodiment of any of the foregoing assemblies, the mule vehicle is mechanically coupled to a tow vehicle when the mule vehicle is towed to the electrified vehicle.

In a further non-limiting embodiment of any of the foregoing assemblies, the mule vehicle is configured to autonomously follow the stranded vehicle while it is towed by the tow vehicle.

In a further non-limiting embodiment of any of the foregoing assemblies, the mule vehicle is configured to mechanically couple to the towed vehicle and to assist the towing of the stranded vehicle with the tow vehicle.

In a further non-limiting embodiment of any of the foregoing assemblies, the mule vehicle is configured to push the stranded vehicle to assist the towing of the stranded vehicle with the tow vehicle.

In a further non-limiting embodiment of any of the foregoing assemblies, the mule vehicle is configured to brake to slow the stranded vehicle to assist the towing of the stranded vehicle with the tow vehicle.

In a further non-limiting embodiment of any of the foregoing assemblies, the mule vehicle is configured to be driven by an operator located on the mule vehicle.

A further non-limiting embodiment of any of the foregoing assemblies, includes the stranded vehicle as the electrified vehicle, and further includes Electric Vehicle Supply Equipment of the mule vehicle that electrically couples the storage battery to the traction battery.

In a further non-limiting embodiment of any of the foregoing assemblies, the Electric Vehicle Supply Equipment comprises a charge cord.

DETAILED DESCRIPTION

This disclosure relates generally to a mule vehicle having a storage battery that can be used to charge a traction battery of an electrified vehicle. If a charge level of the traction battery is sufficiently reduced, the electrified vehicle may be stranded at a location. The mule vehicle can then be towed to the location of the electrified vehicle so that a storage battery of the mule vehicle can be used to recharge the electrified vehicle.

The mule vehicle may be particularly useful for charging the traction battery of an electrified vehicle that is stranded in a location remote from any charge station. Notably, the storage battery of the mule vehicle can be charged as the mule vehicle is towed to the location of the electrified vehicle.

Referring now toFIG. 1, an exemplary mule vehicle10includes a storage battery14, an electric machine18, a power transfer unit20, and a plurality of wheels22. The example mule vehicle10is a battery electric vehicle (BEV) type of electrified vehicle. It should be understood, however, that the concepts described herein are not limited to BEVs and could extend to other mule vehicles including, but not limited to, mule vehicles that are plug-in hybrid electric vehicles (PHEVs), mule vehicles that are hybrid electric vehicle (HEVs), etc.

In an example embodiment, the mule vehicle10employs a drive system that includes a combination of at least the storage battery14, the electric machine18, and the power transfer unit20. When employing this drive system, the mule vehicle10uses energy stored in the storage battery14to power the electric machine18, which generates torque to drive the wheels22through the power transfer unit20. The power transfer unit20can be a transmission gearbox with an epicyclic gear set, for example.

The storage battery14is, in this example, a battery pack comprising a plurality of individual battery cells. The exemplary storage battery14has a relative high energy capacity, say from 100-200 kilowatt hours.

Driving the wheels22with the power transfer unit20propels the mule vehicle10. The drive system can thus be considered an electric drive system.

The electric machine18is a combined motor-generator in this example. In other examples, the electric machine18includes a motor and additionally includes a generator that is separate from the motor.

The electric machine18operates in a motor mode when employing the electric drive system. The electric machine18can also operate in a generator mode. When operating in the generator mode, rotation of the wheels22can drive the electric machine18through the power transfer unit20. The electric machine18converts the mechanical energy from the wheels22into electrical energy that charges the storage battery14. The wheels22can be rotated to drive the electric machine18when, for example, another vehicle is towing the mule vehicle10.

When operating in the generator mode, the electric machine18can also utilize regenerative braking of the wheels22to generate electrical energy that charges the storage battery14. That is, when the mule vehicle10is moving and the wheels22are slowed by regenerative braking, the kinetic energy of the mule vehicle10is converted by the electric machine18into electrical energy that charges the storage battery14.

Referring toFIG. 2with continued reference toFIG. 1, the mule vehicle10additionally includes a charge cord26, a mule control module30, a communication module34, and a mule hitch36.

The charge cord26can be electrically coupled to an electrified vehicle. When electrically coupled to an electrified vehicle, electrical energy from the storage battery14can flow through the charge cord26to charge a traction battery of the electrified vehicle. The mule control module30, in this embodiment, can control electrical communication through the charge cord26.

The charge cord26is an example type of Electric Vehicle Supply Equipment (“EVSE”). The mule vehicle10may include many types of EVSE to facilitate coupling to a wide variety of electrified vehicles. Exemplary EVSE could include charge cords with Type1connector interfaces, Type2connector interfaces (for AC charging), and combined charging system connectors. Other exemplary EVSE incorporated into the mule vehicle10could include quick-charging electrical connectors sold under the CHAdeMO tradename. The mule vehicle10effectively emulates a charge station from the perspective of the electrified vehicle having the traction battery being charged.

In this exemplary embodiment, the charge cord26, and other EVSE, is packaged within a rear of the mule vehicle10. This packaging can facilitate electronically coupling the charge cord26to the electrified vehicle when the mule vehicle10is parked in front of the electrified vehicle. A winding mechanism39is incorporated into the mule vehicle10to wind the charge cord26for storage.

As shown inFIG. 3, the mule hitch36of the mule vehicle10can be mechanically coupled to a tow hitch38of a tow vehicle42, here a tow truck. As the tow vehicle42is driven, the tow vehicle42tows the mule vehicle10when the mule hitch36is mechanically connected to the tow hitch38. Mechanically connected, for purposes of these disclosure, means a physical connection.

The tow vehicle42and the mule vehicle10can be, for example, located at a towing company. The tow vehicle42can tow the mule vehicle10to various locations remote from the towing company location.

Towing the mule vehicle10rotates the wheels22, which can generate electrical power to charge the storage battery14. Regenerative braking of the wheels22of the mule vehicle10as the mule vehicle10is towed by the tow vehicle42can also generate electrical power to charge the storage battery14.

The mule vehicle10, in this example, is relatively low to the ground, which can reduce aerodynamic load and facilitate power generation as the mule vehicle10is towed by the tow vehicle42. That is, the powertrain of the tow vehicle42can deliver a certain maximum continuous power, which may limit the power generation of the mule vehicle10. To facilitate a low road load, the storage battery14is positioned in a vertically low area of the mule vehicle10.

In this example, the communication module34can communicate wirelessly with a communication module52of the tow vehicle42. The wireless communication between the communication module34of the mule vehicle10and the communication module52of the tow vehicle42can include, for example, reporting a state of charge of the storage battery14through the communication module34to the communication module52. A driver of the tow vehicle42can review the state of charge of the storage battery14via a display (not shown) within a cabin of the tow vehicle42.

Another example communication could be a command sent from the communication module52of the tow vehicle42to the communication module34of the mule vehicle10. The command can instruct the mule vehicle10to begin a storage battery charge procedure where rotation of the wheels22causes the storage battery14to charge. When the storage battery charging procedure is not initiated, the mule vehicle10can be towed without rotation of the wheels22charging the storage battery14.

Although the communications between the communication module34of the mule vehicle10and the communication module52of the tow vehicle42are described as wireless communications, other examples could include other types of communications. For example, the mule vehicle10and the tow vehicle42could communicate through wired connections extending along the tow hitch38from the tow vehicle42to the mule vehicle10.

Referring now toFIG. 4with continuing reference toFIGS. 2-3, a stranded vehicle is, in this example, an electrified vehicle60including a traction battery64. If the traction battery64is depleted such that the electrified vehicle60is stranded at a location, an operator of the electrified vehicle60can contact the towing company to request a charge of the electrified vehicle60.

In response to the request, the tow vehicle42mechanically couples the mule vehicle10to the tow vehicle42, and then tows the mule vehicle10to the location of the electrified vehicle60. After the mule vehicle10arrives at the location of the electrified vehicle60, the charge cord26of the mule vehicle10can be electrically coupled to the electrified vehicle60as shown inFIG. 4. The storage battery14in the mule vehicle10can then charge the traction battery64of the electrified vehicle60.

Based on, among other things, a distance that the tow vehicle42and the mule vehicle10must travel to reach the electrified vehicle60, the tow vehicle42can initiate a command through the communication module52to begin the storage battery charge procedure. The storage battery charge procedure can be timed to begin so that when the mule vehicle10reaches the electrified vehicle60, the storage battery14is charged to a desired level, has a state of charge sufficient to charge the traction battery64of the electrified vehicle60, or both.

Further, if a distance that the tow vehicle42and the mule vehicle10must travel to the electrified vehicle60is relatively small, the tow vehicle42may tow the mule vehicle10at a slower speed. This has two effects: firstly, the aerodynamical road load of the tow vehicle42and the mule vehicle10is reduced. As a consequence, a higher fraction of the power of the tow vehicle42can be used for power generation in the mule vehicle10. Secondly, the tow vehicle42and mule vehicle10will take longer to reach the electrified vehicle60, and hence have more time for charging so that the mule vehicle10will have sufficient energy stored in the storage battery14to charge the traction battery64of the electrified vehicle60.

In this example, the mule vehicle10can DC fast charge the traction battery64, which can reduce a time period required to charge the traction battery64of the electrified vehicle60when compared to, for example, an AC charge. In another example, the mule vehicle10couples to the electrified vehicle to AC charge the traction battery64.

In some examples, the AC charging provided by the mule vehicle10includes charges up to an E-phase of 43 kilowatts, and the DC charging includes relatively high powered charging such as 150 kilowatts at 400 Volts or 350 kilowatts at 800 Volts.

The mule control module30can provide control over the charging of the traction battery64with the storage battery14, such as by controlling a rate of the charging. The mule control module30can include an interface, such as a touch screen, that an individual can interact with to start a charging of the traction battery64, stop a charging, control a rate of charging, etc. The mule control module30is, in this example, located on a right side (or passenger side) of the mule vehicle10. If the electrified vehicle60is stranded on a right side of a road, which may be typical, the individual can interact with the mule control module30on a side of the mule vehicle10away from the flow of traffic along the road.

In an embodiment, the mule control module30includes a processing unit and non-transitory memory for executing various charging control strategies. The mule control module30can receive and process various inputs when controlling the charging, such as an input indicating that the operator of the tow vehicle42, or the driver of the electrified vehicle60, is requesting that the charging begin.

The processing unit, in an embodiment, is configured to execute one or more programs stored in the memory of the mule control module30. A first exemplary program, when executed, calculates an efficient rate at which to charge the traction battery64.

In an exemplary non-limiting embodiment shown schematically inFIGS. 5A and 5B, the storage battery14of the mule vehicle10can be split into two separate battery packs14A,14B of approximately 400 Volts each. The mule control module30can transition a switch66to place the battery packs14A,14B in parallel or series. When the battery packs14A,14B are in the parallel as shown inFIG. 5A, output from the EVSE can be 400 Volts. When the battery packs14A,14B are in series as shown inFIG. 5B, output from the EVSE can be 800 Volts. The mule control module30can control transitions of the switch to charge the traction battery64with 400 Volts or 800 Volts as desired.

From time to time, the electrified vehicle60may require towing by the tow vehicle42. For example, the tow vehicle42and the mule vehicle10could arrive at the electrified vehicle60and determine that electronic complications prevent driving the electrified vehicle60, even if the traction battery64is recharged. In such situations, the tow vehicle42may tow the electrified vehicle60back to the location of the towing company, or to another location.

Referring toFIG. 6with reference toFIGS. 1 and 2, to tow a stranded vehicle, which is the electrified vehicle60in this example, the mule vehicle10is first mechanically decoupled from the tow hitch38of the tow vehicle42. A vehicle hitch76of the electrified vehicle60can then be mechanically coupled to the tow hitch38. The electrified vehicle60thus substantially takes the place of the mule vehicle10.

To avoid leaving behind the mule vehicle10, the mule vehicle10in this exemplary non-limiting embodiment is configured to autonomously follow the electrified vehicle60as the tow vehicle42drives and tows the electrified vehicle60.

Prior to autonomously following the electrified vehicle60, the mule vehicle10can be placed into a learning mode where the mule vehicle10scans a rear of the electrified vehicle60. In the learning mode, sensors on the mule vehicle10detect and store characteristics of the rear of the electrified vehicle60. The sensors could utilize echoes and other types of sensory recognition techniques to detect the characteristics. The characteristics can be stored within the memory of the mule control module30and referenced as required.

After the learning mode is sufficiently complete, the mule vehicle10is placed in a follow mode. Then, as the tow vehicle42moves forward and begins to tow the electrified vehicle60, the mule vehicle10follows the electrified vehicle60towed by the tow vehicle42. The mule vehicle10can rely on optical, LIDAR, and other sensors for tracking a distance to the electrified vehicle60as the mule vehicle10autonomously follows the electrified vehicle60.

When autonomously following the electrified vehicle60, the mule vehicle10can use electrical energy from the storage battery14to power the electric machine18to drive the wheels22.

Also, the communication module34of the mule vehicle10can remain in communication with the communication module52of the tow vehicle42. The communications could cause the charging control module to activate lighting systems on the mule vehicle10, such as brake lights, in response to braking of the tow vehicle42. Signals from the communication module52can also cause the mule vehicle10to accelerate, decelerate, steer to the left or right, slow down, etc.

In this exemplary embodiment, due to the relatively close distance between the mule vehicle10and the electrified vehicle60during the autonomous following, the mule vehicle10does not need to fully interpret traffic situations, traffic lights, etc. Instead, the operator of the tow vehicle42interprets these traffic situations and controls the tow vehicle42accordingly. The mule vehicle10then continues to follow the electrified vehicle60. As the mule vehicle10does not need to fully interpret traffic situations, the equipment required for autonomous operation of the mule vehicle10is simplified. In some examples, only a basic camera or radar sensor on the mule vehicle10is required.

In some examples, steering the mule vehicle10when autonomously following the electrified vehicle relies on the characteristics of the electrified vehicle60detected and stored during the learning mode. A characteristic could include for example, a location of a tail light of the electrified vehicle60, or a laterally outermost edge of the electrified vehicle60. The mule vehicle10is then automatically steered by the mule control module30in response to these features being repositioned as the electrified vehicle60is towed.

For example, if a camera of the mule vehicle10detects that a right tail light of the electrified vehicle is deviating or moving to the left, the mule vehicle10is automatically steered to the left until the right tail light returns to a target position. The mule vehicle10can utilize a closed loop controller (e.g., Proportional Integral, Proportional Derivative, or Proportional Integral Derivative) to control steering based on the detected movement of the right tail light in the electrified vehicle60.

The mule vehicle10can be trained on particular features during the learning mode. The automatic steering of the mule vehicle10based on the detected movement of features in the electrified vehicle60can be in addition to, or instead of, steering control commands sent by the communication module52to the mule vehicle10. The mule vehicle10, during the learning mode, may prompt the tow vehicle42or the electrified vehicle60to activate certain features to assist with the learning. The mule vehicle10may prompt the operator to activate, for example, a turn signal of the electrified vehicle60, which helps the mule vehicle10identify and learn the location of the turn signal.

In some examples, if the sensors on the mule vehicle10become unable to detect the electrified vehicle60, a steering angle of the mule vehicle10can be kept constant and friction brakes of the mule vehicle10are applied to bring the mule vehicle10to a controlled stop. A snow plow, for example, could direct snow between the mule vehicle10and the electrified vehicle60, which could interfere with the sensors of the mule vehicle10detecting the electrified vehicle60.

If a control system was able to use the sensory data obtained to interpret the geometry of the road before the direct line of sight between the mule vehicle10and the electrified vehicle60was lost, the stored geometry of the road may be followed. Further, if satellite and navigation information about the geometry of the road were saved within the memory of mule vehicle10as road data, that road data could be followed when bringing the mule vehicle10to a controlled stop.

Notably, a person having skill in this art and the benefit of this disclosure would understand how to configure a vehicle to autonomously follow another type of towed vehicle utilizing a learning mode and a follow mode. For example, non-electrified, (i.e., conventional) vehicles may require being towed to a location where they can be repaired. In such examples, the mule vehicle10can autonomously follow the non-electrified vehicle that is being towed by the tow vehicle42.

Referring now toFIG. 7, in another exemplary embodiment, the mule hitch36of the mule vehicle10is mechanically coupled to a tow hitch78of a towed vehicle60A towed by the tow vehicle42. The towed vehicle60A is, in this example, a stranded vehicle that is relatively large and non-electric (i.e., conventional). The mule vehicle10can assist the tow vehicle42with towing the towed vehicle60A, rather than autonomously following the towed vehicle60A. Assisting the tow vehicle42with towing the towed vehicle60A can, among other things, reduce fuel consumption of the tow vehicle42during the towing.

The towing of the towed vehicle60A can be assisted by the mule vehicle10in many ways. For example, if the tow vehicle42is braking to slow the towed vehicle60A, the mule vehicle10can brake to slow the towed vehicle60A. Further, the mule hitch36and the tow hitch78can be configured to permit the mule vehicle10to push the towed vehicle60A, and thereby assist in moving the towed vehicle60A forward. The pushing of the towed vehicle60A can reduce the towing load on the tow vehicle42.

Referring now toFIG. 8with reference toFIG. 4, another exemplary mule vehicle10A includes a cabin area80occupied by an operator84. Like the mule vehicle10, the mule vehicle10A includes the storage battery14that can be charged when the mule vehicle10A is towed by the tow vehicle42, and can be used to charge the traction battery64of the electrified vehicle60.

As required, the mule vehicle10A can be driven by the operator84independently from the tow vehicle42. Initially, the mule vehicle10A can be towed by the tow vehicle42to a location of the electrified vehicle60. If the tow vehicle42is then required to tow the electrified vehicle60, the operator84can drive the mule vehicle10A back to, for example, the towing station. Since the mule vehicle10A can be driven by the operator84, the mule vehicle10does not need to autonomously follow the electrified vehicle60and does not need to be mechanically coupled to the electrified vehicle60. In some examples, the operator84can use the mule vehicle10A for transportation when not returning from the location of the electrified vehicle60, such as for commuting the operator84to and from work.

Features of the disclosed examples include a mule vehicle having a storage battery that can be charged when the mule vehicle is towed. Time spent charging the storage battery with a charging station can thus be reduced or eliminated.

The mule vehicle, in some embodiments, can be mechanically coupled to another vehicle towed by a tow vehicle and assist in the towing of the other vehicle by, for example, assisting in braking the other vehicle or by pushing the other vehicle.

In some embodiments, the mule vehicle can be mechanically decoupled from the other vehicle towed by the tow vehicle, and configured to autonomously follow the other vehicle. An operator driving the tow vehicle is thus not required. Instead, a single driver operating the tow vehicle can return the tow vehicle, the other vehicle, and the mule vehicle to, for example, a service station.

In some embodiments, the mule vehicle can be driven by a driver in a cabin of the mule vehicle.