Hybrid utility vehicle

A hybrid vehicle may be a series hybrid or a parallel hybrid vehicle. One embodiment of a parallel hybrid vehicle includes an engine, a transmission coupled to the engine, a front drive coupled to the transmission through a prop shaft, a rear drive coupled to the transmission, a traction motor drivingly coupled to the prop shaft, and a battery to operate the traction motor.

FIELD OF THE DISCLOSURE

The present application relates to a utility vehicle and, more particularly, a hybrid utility vehicle configured to operate in various drive modes.

BACKGROUND OF THE DISCLOSURE

Electric vehicles are known to have at least one battery pack which may be operably coupled to an electric motor for charging the battery pack and/or for driving the wheels of the vehicle. A hybrid vehicle, however, has both an electric motor and an internal combustion engine. In one embodiment of a hybrid vehicle, the engine and the battery packs operate in series, meaning that the battery packs provide the power or energy for driving the wheels and the engine operates to charge the battery packs. Alternatively, in another embodiment, a hybrid vehicle may be a parallel hybrid vehicle, meaning that the battery packs provide the power or energy to drive either the front or rear wheels but the engine provides the motive power to drive the other set of wheels.

SUMMARY OF THE DISCLOSURE

In one embodiment, a parallel hybrid power train comprises an engine, an electric motor/generator, a transmission having an input shaft, at least a second shaft drivingly coupled to the input shaft, the engine and the electric motor/generator being coupled to one of the input or second shafts, and at least a first output; and a final drive assembly operably coupled to the first output, the final drive assembly being profiled for driving ground engaging members of a vehicle.

The parallel hybrid power train may comprise a silent mode wherein the electric motor/generator operates to drive the transmission output. The parallel hybrid power train may also allow the engine driven generator to charge the battery. In this embodiment, the parallel hybrid power train comprises a charge at rest mode wherein the engine is run to only charge the batteries through the engine driven motor/generator.

The parallel hybrid power train may also comprise a full performance mode wherein the motor/generator and engine are both operated to add torque to the transmission output.

Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

The embodiments disclosed below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may utilize their teachings. While the present disclosure is primarily directed to a utility vehicle, it should be understood that the features disclosed herein may have application to other types of vehicles such as other all-terrain vehicles, motorcycles, snowmobiles, and golf carts.

Referring first toFIGS. 1-3, an illustrative embodiment of a hybrid utility vehicle10is shown, and includes ground engaging members, including front ground engaging members12and rear ground engaging members14, a powertrain assembly16(FIG. 2), a frame20, a plurality of body panels22coupled to frame20, a front suspension assembly24, a rear suspension assembly26, and a rear cargo area28. In one embodiment, one or more ground engaging members12,14may be replaced with tracks, such as the PROSPECTOR II tracks available from Polaris Industries, Inc. located at 2100 Highway 55 in Medina, Minn. 55340, or non-pneumatic tires as disclosed in any of U.S. Pat. No. 8,109,308, filed on Mar. 26, 2008; U.S. Pat. No. 8,176,957, filed on Jul. 20, 2009; and U.S. Pat. No. 9,108,470, filed on Nov. 17, 2010; and U.S. Patent Application Publication No. 2013/0240272, filed on Mar. 13, 2013, the complete disclosures of which are expressly incorporated by reference herein. Vehicle10may be referred to as a utility vehicle (“UV”), an all-terrain vehicle (“ATV”), or a side-by-side vehicle (“S×S”) and is configured for travel over various terrains or surfaces. Furthermore, vehicle may be similar to that disclosed in U.S. Patent application publication 20170355259, the complete disclosure of which is expressly incorporated by reference herein. More particularly, vehicle10may be configured for military, industrial, agricultural, or recreational applications.

Powertrain assembly16is operably supported on frame20and is drivingly connected to one or more of ground engaging members12,14. As shown inFIGS. 2-5, powertrain assembly16may include an engine30(FIG. 2) and a transmission, for example a continuously variable transmission (“CVT”)32(FIG. 3) and/or a shiftable transmission34. Transmission34is shown as a transaxle which includes a combination shiftable transmission and final drive. However, the transmission and final drive may be separated and coupled together as shown in U.S. Pat. No. 8,596,405. Engine30may be a fuel-burning internal combustion engine, however, any engine assembly may be contemplated, such as hybrid, fuel cell, or electric engines or units. In one embodiment, powertrain assembly16includes a turbocharger (not shown) and engine30is a diesel internal combustion engine. Additional details of CVT32may be disclosed in U.S. Pat. Nos. 3,861,229; 6,120,399; 6,176,796 6,860,826; and 6,938,508, the complete disclosures of which are expressly incorporated by reference herein.

As shown inFIG. 1, front suspension assembly24and rear suspension assembly26may be similar to that described in U.S. Pat. No. 7,819,220, filed Jul. 28, 2006, the complete disclosure of which is expressly incorporated by reference herein. Alternatively, rear suspension assembly26may be as shown and described in U.S. Patent Application Publication No. 2012/0031693, filed Aug. 3, 2010, titled “SIDE-BY-SIDE ATV, the complete disclosure of which is expressly incorporated by reference herein.

Referring again toFIG. 1, vehicle10includes an operator area40supported by frame20, and which includes seating for at least an operator and a passenger. Illustratively, one embodiment of vehicle10includes three seats, including an operator seat42, a front passenger seat44, and a middle seat46. Operator seat42includes a seat bottom and a seat back. Similarly, front passenger seats44and46include a seat bottom and a seat back.

As described above, vehicle10includes frame20supported by ground engaging members12,14. Illustratively, rear frame portion48(FIGS. 4 and 5) supports powertrain assembly16and rear cargo area28. Vehicle10also comprises an overhead or upper frame portion50. Upper frame portion50is coupled to frame20and cooperates with operator area40to define a cab of vehicle10. Additional details of vehicle10may be disclosed in U.S. Pat. No. 8,998,253, filed Mar. 28, 2013, the complete disclosure of which is expressly incorporated by reference herein.

Referring toFIGS. 2 and 3, in one embodiment, vehicle10is a series hybrid utility vehicle configured for engine and electrical operation. Vehicle10includes a motor/generator60operably coupled to transmission34to provide input power to the transmission as further described herein. Vehicle10further includes a plurality of batteries70for driving motor/generator60and which can be charged by the engine30as further described herein. While only one battery70is shown, it should be understood that multiple batteries may be coupled together or a battery pack may be provided. An engine control unit74is provided to assist in the control of the motor/generator60. As shown best inFIG. 3, vehicle10further includes a transmission rear output at78for coupling to half shafts (not shown) to drive the rear wheels14, and a front output80which couples to a drive shaft82which in turn is coupled to a front final drive84having a front output at86. It should be appreciated that half shafts (not shown) are coupled to the front wheels12and driven by output at86.

With reference again toFIGS. 4 and 5, powertrain16is shown mounted within rear frame portion48. As shown, rear frame portion48includes a lower frame portion90which supports engine30and transaxle34. Rear frame portion48further includes upstanding posts92coupled to longitudinal rails94which support rearwardly extending frame tubes96which enclose the powertrain16yet provide support for utility bed28(FIG. 1). A seat support98is provided which is supported by longitudinal frame tubes94and enclose battery70and engine control unit74. Seat support94supports the operator and passenger seats42,44,46.

With reference now toFIGS. 6-8, the mounting of the motor/generator60and the coupling to the transaxle34will be described in greater detail. As shown best inFIG. 7, transaxle34includes an upper input shaft100which is internally split to provide a shaft portion102and shaft portion104. Shaft portion102receives power input from CVT32whereas shaft portion104receives power input from motor/generator60. As is known, engine30would drive a drive clutch of CVT32which internally drives a driven clutch of CVT32, and the driven clutch of CVT32would couple to the shaft portion102. The hybrid drive aspect will now be described in greater detail herein, with a first discussion regarding the mounting of the motor/generator60to the transmission34.

With reference now toFIGS. 7, 7A and 8, transaxle34includes three threaded posts or studs110(FIG. 7A) extending outwardly from a housing112of the transaxle on the same side of the transaxle as shaft portion104. As described herein, studs110correspond with lock nuts114. As shown best inFIG. 7, a mounting assembly120is provided for mounting motor/generator60to the transaxle34. As shown inFIGS. 7 and 7A, mounting assembly120includes a spacer124, lock nuts126and128, inner bracket130, bearing132and outer bracket134. Spacer124includes a threaded portion140, a hexagonal portion142and a threaded portion144. It should be appreciated that the transaxle housing112includes a threaded opening146positioned around shaft portion104, which threadedly receives threaded portion140of spacer124. Spacer124also includes an opening at148which is larger than shaft portion104such that when spacer124is threaded into opening146, shaft portion104extends through spacer124but does not contact spacer124. Lock nut126is threaded onto threaded portion144of spacer124and may float in order to define the lateral position of inner bracket130as described herein.

Once coupler124is attached to threaded opening146, inner bracket130may be mounted to transaxle34. As shown best inFIG. 7A, inner bracket130includes three apertures at150which correspond with threaded posts110such that inner bracket130may be positioned over transaxle34. It should also be appreciated that lock washer126is moved to an inward most position to allow the positioning of inner bracket130. Inner bracket130includes an opening at160which includes an enlarged diameter portion162, reduced diameter portion164, shoulder166and opening168. It should be appreciated that threaded portion144of spacer124may be received through opening168of inner bracket130and that lock washer128is positioned through opening162and is threadably received on the threaded portion144which protrudes through opening168. Bearing132is then received within the diameter portion162of opening160. This can be seen best in the cross-sectional view ofFIG. 9. With bearing132positioned within diameter portion162, shaft104is carried within the bearing132. Lock nuts126and128are tightened against bracket130, as shown best inFIG. 9. Lock nuts114are also coupled to the threaded studs110, which couples the inner bracket130to the transmission34.

Outer bracket134is shown best inFIG. 8, and includes a plurality of recessed openings170which align with threaded bosses172on motor/generator60to receive cap screws174therethrough to couple the outer bracket134to the motor/generator60. Outer bracket134further includes openings180which align with threaded openings182on motor/generator60and receive fasteners184therethrough to further couple outer bracket134to motor/generator60. The two brackets130,134are now aligned which also aligns shaft portion104with output shaft190of motor/generator60. Shaft190is internally splined which couples with shaft portion104. Brackets130and134may then be coupled together by way of fasteners200extending through apertures202of bracket130and into threaded openings204of outer bracket134. As shown inFIG. 7, fasteners210may also be received through apertures212of bracket134and into threaded engagement with threaded apertures214of bracket130. Thus as coupled together as described above, either the motor/generator60or CVT32may provide input power to the transaxle through corresponding input shafts104,102. This provides multiple modes of operation of the hybrid vehicle as described herein.

With reference now toFIG. 10, the inner gearing of the transaxle34will be described in greater detail. As shown, shaft portions102and104are separated but may be coupled together by way of coupler220. The end of shaft102has a splined portion at222and the end of shaft104has a splined portion224, where both splined portions222and224extend into a splined coupling portion of coupler220. Coupler220is laterally movable along the direction of arrow designated as226such that when in the position shown inFIG. 10, the two.104are coupled together and act as one. If the coupler220is moved to the left as viewed inFIG. 10, shaft portion104is decoupled from shaft portion102whereas when the coupler is moved to the right as viewed inFIG. 10, shaft portion102is decoupled from shaft portion104. As shown, shaft portion102includes a gear at230and shaft portion104includes a gear at232. An intermediate shaft240is provided which provides a gear242in meshing engagement with gear230and a gear244in meshing engagement with gear232. Shaft240further includes a gear246. As shown inFIG. 10, gear242may be laterally movable in the direction of arrow248, for example by way of a dog clutch (not shown) whereby gear242may be moved into and out of meshing engagement with gear230. In a similar manner, and as shown inFIG. 10, gear244may be laterally movable in the direction of arrow249, for example by way of a dog clutch (not shown) whereby gear244may be moved into and out of meshing engagement with gear232.

A lower shaft250is provided having a gear252in meshing engagement with gear246and shaft250includes a gear254in meshing engagement with a gear256. It should be appreciated that gear256provides the output to transaxle outputs78and80(FIG. 3). It should also be appreciated that a combination of gears232and244represent a low gear, that is a high torque gear, whereas the combination of gears230and242represent a high gear, that is a higher speed gear. Thus with the coupling as described, multiple modes of operation of the transaxle are available. For example as shown inFIG. 10, a power path260provides for an engine drive for low gear, power path262provides engine drive for a high gear, power path264provides for a charge at rest mode, power path266provides a charge and drive mode and power path268provides a motor only drive in low gear. The various modes will now be described with relation toFIGS. 10A-10E.

With reference first toFIG. 10A, the engine only in high gear power path is shown where coupler220is shown moving to the right along path226such that shaft portion104is decoupled from shaft portion102. Thus, power from the CVT34to shaft102provides power along power path280to power path282(through gears230,242), through power path284(through shaft240), through power path286(through gears246,252), through power path288(through shaft250) and through power path290(through gears254,256). As mentioned above, the power through power path290provides power to both outputs of the transaxle at80and86.

With reference now toFIG. 10B, the power path will be described to define a “charge and drive mode” whereby power from only the engine30provides input power through the low gear setting of transaxle34. In this mode, coupler220couples together shaft portions102and104and gear242is moved to the right as viewed inFIG. 10Bto decouple gear242from gear230. Thus power moves along power path300(through shaft portions102and104) to power path302(through gears232,244), through power path304(through shaft240), and then through power paths286,288and290as described above. As shown in this mode inFIG. 10B, power is also provided to motor/generator60(in the generator mode) through power path301to charge the batteries70.

With reference now toFIG. 10C, a “full performance” mode is shown where input may be received from both the engine30and the motor/generator60where the power path is virtually identical to that shown inFIG. 10B, with the exception that a power path310is also provided from motor/generator60through shaft104. The power path therefore includes input power paths300and310which couples to power paths302,304,286,288and290.

With reference now toFIG. 10D, an electric only “stealth” mode is shown where coupler220is moved to the left as viewed inFIG. 10Dto a position to decouple shaft portion102from shaft portion104. Thus, the motor provides input power along power path312(through shaft104) to power path314(through gears232,244), along power path316(through shaft240), through power path318(through gears246,252), through power path320(through shaft250) and through power path322(through gears254,256).

With reference now toFIG. 10E, a “charge at rest” mode is shown where coupler220couples together shaft portions102and104and where gears242and244are moved to the right as viewed inFIG. 10Eto decouple them from their corresponding gears230and232such that only the shaft portions102,104are driven and shafts240and250remain idle. In this mode, the vehicle is not moving and therefore at rest and only the generator portion of the motor/generator60is utilized for recharging the batteries70.

With reference now toFIGS. 11-16G, a second embodiment of hybrid drivetrain will be described. With reference first toFIGS. 11-15, a hybrid drive is shown at416which is similar to the hybrid drive16described above. Hybrid drive416includes engine430, transaxle434, motor/generator460, batteries470, motor controller474, transaxle output478, front output480(FIG. 13), drive shaft482, front final drive484and front output486. The difference in the embodiment ofFIG. 11from that ofFIG. 2relates to the manner in which motor/generator460is coupled to the transmission434. In this embodiment, motor/generator460is coupled to the transaxle434by way of a belt490and pulleys or sheaves492,494(FIG. 14) which provides power into the transaxle as described herein. As shown inFIG. 12, hybrid powertrain416is packaged in the rear frame portion48in much the same manner as described above with respect to hybrid powertrain16. Motor460is coupled to transmission434by way of mounting assembly520, as shown best inFIGS. 14 and 15.

With reference now toFIGS. 16-16G, the operation of the hybrid powertrain416will be described in greater detail. With reference first toFIG. 16, transmission434includes an input shaft502which is a solid shaft having gears at630and632. A second shaft540is included which includes gears642and644which mesh with gears630and632on shaft502, respectively. Gear642may be moved laterally out of meshing engagement with gear630by movement in the direction of arrow648while gear644may be moved into and out of meshing engagement with gear632along movement according to arrow651. Shaft540further includes a third gear at646which couples with gear652on shaft650. A clutch620moves laterally in the direction of arrow626which moves gear652into and out of meshing engagement with gear646. Shaft650further includes a gear654which is in meshing engagement with gear656. It should be appreciated that gear656provides the output to transaxle outputs478and480(FIG. 13). As with hybrid drive16, hybrid drive416has multiple modes of operation.

With reference first toFIG. 16A, a “charge and drive” mode in high gear is shown where power into shaft502from CVT34provides power along power path700(through shaft502) to power path702(through gears630,642) along power path704(through shaft540) to power path706(through gears648,652) to power path708(through shaft650) to power path710(through gears654,656). At the same time as shaft is powered by input to shaft502, a power path712is provided which couples to sheave492which powers sheave494through belt490. This provides charging of batteries70while the motor/generator460is in the generator mode. In this mode, gear644moves in the direction of arrow651to disengage from gear632.

As shown inFIG. 16B, a “charge and drive” mode can also be utilized in the low gear whereby power from CVT to input shaft502provides a power path720(through shaft502) to power path722(through gears632,644) which provides input to shaft540providing a power path724(through shaft540) to power path726(through gears648,652) to power path728(through shaft650) and then to power path730(through gears654,656). At the same time power is provided to shaft540, a power path732is provided (through shaft540) to power path714provided by the belt490driving sheaves492and494. In this mode, gear642moves in the direction of arrow648to disengage from gear630.

With reference now toFIG. 16C, a “full performance” mode is shown in a low gear, which is substantially similar to the embodiment ofFIG. 16B, with the exception that power is provided from the motor/generator460to shaft540through power path740such that the motor/generator460is operating in the motor mode and assisting in the driving of shaft540. In a similar manner, and as shown inFIG. 16D, a “full performance” mode is shown in high gear which is substantially similar to that described with respect toFIG. 16A, with the exception that power is provided from motor/generator460through power path740to drive shaft540.

An electric only drive mode is shown inFIG. 16Ewhere gears642and644are disengaged such that power from only motor/generator460in the motor mode is driven to shaft540through power path750to power path752(through shaft540) to power path754(through gears648and652) to shaft650through power path756and to power path758(through gears654,656).

Finally and with respect toFIG. 16F, a “charge at rest” mode is shown through the low gear such that input from the CVT to shaft502provides input to power path770(through gears632,644) to power path772(through shaft540) and through power path774(through belt490and sheaves492,494). It should be appreciated that clutch620in this configuration moves gear652in the direction of arrow626to take gear652out of meshing engagement with gear648, such that shaft650is not rotated. Gear642is also disengaged from gear630having been moved in the direction of arrow648.

A similar charge at rest mode is shown inFIG. 16G, through the high gear whereby input power to shaft502provides input through power path780(through shaft502) to power path782(through gears630,642) to power path784(through shaft540) and to power path786(through belt490and driving sheaves492,494). As in the embodiment ofFIG. 16, gear652is moved by clutch620out of meshing engagement with gear648by moving gear in the direction of arrow626. Gear644is also disengaged from gear632having been moved in the direction of arrow651.

Finally, a third embodiment of powertrain could be provided where a motor/generator is mounted on the same side as the CVT, where the motor/generator is coupled to the driven CVT pulley. This could be done by a belt and sheaves for example, where one sheave is coupled to the motor/generator (similar to the embodiment shown inFIG. 14) and the other sheave is coupled to the CVT pulley shaft.

With respect toFIG. 17, a control system800of vehicle10may be included to control operation of any of the powertrain assemblies disclosed herein. Control system800includes a hybrid control unit (“HCU”)801which is operatively coupled to various control units through a communications network or device, such as a CAN bus802. For example, HCU801may be operatively coupled to an engine control unit (“ECU”)804, a motor control unit (“MCU”)806, and a transmission control unit (“TCU”)808. It may appreciated that ECU804may be the same as engine control unit74ofFIG. 2and MCU806may the same as motor controller474ofFIG. 12. In this way, various components of the powertrain assemblies disclosed herein may be controlled by individual control units or controllers. However, in other embodiments, the various controllers or control units may be defined as a single controller or control unit but separated by software for individual control of the motor, engine, batteries, and other powertrain components.

Referring still toFIG. 17, HCU801is configured to receive inputs or requests from other vehicle components, defined as driver inputs/requests810. For example, various driver inputs/requests810may be provided from the accelerator pedal, the gearbox, and the clutch. In one embodiment, driver inputs/requests810may include an input to the accelerator pedal, a requested gearbox position, and a requested driving direction (e.g., forward or reverse).

Control system800may be used to provide various modes for operating vehicle10. In one embodiment, vehicle10is configured to operate in a Downhill Speed Control Mode, a Hill Hold Control Mode, a Snow Plow Control Mode, and an Electric Drive-Away Control Mode, as disclosed herein.

Downhill Speed Control Mode

When vehicle10operates in the Downhill Speed Control Mode, vehicle10is driving downhill and, due to gravity, the velocity of vehicle10can increase. Motor/generator60,460may assist with braking vehicle10to a specific speed without applying the mechanical brake. More particularly, a negative torque may be applied relative to the direction of driving to maintain a constant velocity of vehicle10without the need to apply the mechanical brake when driving downhill. Additionally, when in the Downhill Speed Control Mode, battery70may be recharged. For example, motor/generator60,460may be used as a generator to recharge battery70when the charge on battery70is less than 100%.

As shown inFIG. 18, when in the Downhill Speed Control Mode, control system800may utilize at least one look-up table to determine the torque requested on motor/generator60,460. More particularly, at812, the accelerator pedal input is determined and compared to the regenerative threshold at814. The comparison of the accelerator pedal input to the regenerative threshold leads to a true/false path at816, where a zero input at818may be provided or an output from826be provided, in order determine the regenerative torque. More particularly, at816, there is a determination that, if the input is true, then the output is equal to the first output; however, if the determination is false or not true, then the output is equal to the second output. For example, as shown at820, when the RPM of motor/generator60,460is less than zero, the regenerative torque is determined following821and used for generating the torque request on motor/generator60,460at822. Again, at821, if the determination of the input is true, then the output is equal to the first output; however, if the determination at821is that the input is false or not true, then the output is equal to the second output. As such, if the state-of-charge on the battery is in a predetermined range for regeneration, the accelerator pedal input is below the regenerative threshold, and the RPM of motor/generator60,460is above a threshold, then the braking torque will increase to a maximum value. However, if the RPM of motor/generator60,460decreases to a value below the regenerative threshold, the regenerative torque will be increased to zero to bring vehicle10to a smooth stop. In each state, if the accelerator pedal input exceeds the minimum regenerative threshold, vehicle10will return an idle state.

Additionally, as shown at823, the absolute value of motor/generator60,460is used with respect to a look-up table at824to determine a signal or input, as shown at826, in order to arrive at the true/false path at816. Also, referring still toFIG. 18, at828shows that the accelerator pedal is sealed from 1-0 for the range of 0 to the regenerative threshold in order to arrive at the signal(s) or input at826. In may be appreciated that826in bothFIGS. 18 and 19denote a multiplication of the two input signals.

With respect to830, the accelerator pedal input is compared to a look-up table at832to determine the acceleration torque. The acceleration torque is then used to determine the torque requested for motor/generator60,460, as shown at822. It may be appreciated that, outside of the state flow shown inFIG. 18, the regenerative torque will be scaled to the range of the accelerator pedal between zero and a minimum pedal regenerative input to allow the driver to actively control the braking torque over the throttle accelerator pedal. These regenerative controls of vehicle10may be used to request a regenerative torque or an acceleration torque from motor/generator60,460.

Hill Hold Control Mode

When vehicle10operates in the Hill Hold Control Mode, control system800prevents vehicle10from rolling backwards without applying the brake pedal when stopping on steep grades of terrain. More particularly, motor/generator60,460may be used to fully stop vehicle10or allow vehicle10to roll backwards at a controlled and slow speed.

With respect toFIG. 19, the open-loop, look-up table approach ofFIG. 18also may be used during the Hill Hold Control Mode. If vehicle10tends to roll down hill and the accelerator pedal position is zero, then the acceleration torque also will be zero. However, because motor/generator60,460will start to spin, the braking torque, as shown as determined following826, will increase and slow down vehicle10.

Snow Plow Control Mode

To perform various tasks, such as plowing snow or allowing for a load at the front end of vehicle10, the operator desires to have the ability to quickly change between forward and reverse. Additionally, when in the forward mode, vehicle10must be capable of pushing or otherwise handling heavy loads. When in the Snow Plow Mode, vehicle10is driven forward using engine30,430. Engine30,430may be used alone or in combination with motor/generator60,460. When vehicle10is driven in reverse, only motor/generator60,460is used and engine30,430idles. The driver has the full power and torque available while driving forward and has the option to quickly change to reverse without any mechanical shifting required. More particularly, the transmission position may be in “LOW” in both driving directions, thereby allowing this change in directions to occur without any mechanical shifting. As such, when vehicle10is driving in the forward direction, engine30,430provides torque while motor/generator60,460provides a positive torque; however, when vehicle10is driving in the reverse direction, engine30,430idles while motor/generator60,460provides negative torque. It may be appreciated that the forward/reverse selection input may be any switch, treadle pedal, or other mechanism which provides an electrical signal or CAN message for the different requested states or driving directions.

Electric Drive-Away Control Mode

To allow for improved low-speed drivability and maneuvering, control system800may allow vehicle10to be driven in an Electric Drive-Away Control Mode. In this mode, when vehicle10is operating as a hybrid vehicle, whereby both engine30,430and motor/generator60,460are used to drive vehicle10, vehicle10may initially start moving using only motor/generator60,460to allow for smooth operation of vehicle10at low speeds. When the speed of vehicle10increases to a predetermined threshold and the clutch engages such that both motor/generator60,460and engine30,430are used to drive, vehicle10then operates at full performance.

More particularly, as shown inFIG. 20, when at840in a low-speed drive-away/maneuvering operation of vehicle10, only motor/generator60,460is used and is set to a torque control mode. As the speed of vehicle10increases above a predetermined threshold, the speed of engine30,430increases, as shown at842, and the engine speed may equal the speed of the driven clutch. Specifically, at842, the speed of the secondary clutch of the CVT is monitored, for example it may be known through the wheel-based speed of motor/generator60,460. Engine30,430may be operated in a speed-controlled mode and the speed of engine30,430and the CVT driven clutch may be synchronized. It may be appreciated that motor/generator60,460remains in the torque-control mode at842. As shown at844, for normal driving operation of vehicle10at speeds above the threshold, engine30,430may be set to the torque-control mode such that both motor/generator60,460and engine30,430are in the torque-control mode.