Systems and methods for operating a vehicle that includes a continuously variable transmission are described. The systems and methods adjust engine speed according to one of a plurality of engine speed to vehicle speed profiles so that driveline noise, vibration, and harshness may be reduced. The different engine speed to vehicle speed profiles provide different levels of engine braking.

A hybrid electric vehicle (HEV) that includes one or more controller(s) configured to manage electric only and combustion engine drive modes, and at start-up, to generate a trip distance, and to detect an electric drive range, and battery, cabin, and powertrain thermal demands, among other conditions. The controller(s) engage a combustion engine drive mode if the distance exceeds the range, and the thermal demands exceed respective thresholds. The controller(s) also engage an electric drive mode if the range exceeds the distance, and the threshold exceed the thermal demands. Further variations include the controller(s) responsive to receiving a destination, and communicating the destination to a navigation system, and detecting if a charge event is likely to occur at the destination. In other arrangements, the controller(s) also adjust the trip distance upon detecting an historical probability of a charge event at the destination and whether the destination is a final destination.

A hybrid electric vehicle (HEV) that includes one or more controller(s) configured to manage electric only and combustion engine drive modes, and at start-up, to generate a trip distance, and to detect an electric drive range, and battery, cabin, and powertrain thermal demands, among other conditions. The controller(s) engage a combustion engine drive mode if the distance exceeds the range, and the thermal demands exceed respective thresholds. The controller(s) also engage an electric drive mode if the range exceeds the distance, and the threshold exceed the thermal demands. Further variations include the controller(s) responsive to receiving a destination, and communicating the destination to a navigation system, and detecting if a charge event is likely to occur at the destination. In other arrangements, the controller(s) also adjust the trip distance upon detecting an historical probability of a charge event at the destination and whether the destination is a final destination.

A method of controlling a continuously variable electric drivetrain (CVED) including a high ratio traction drive transmission and at least one of a first motor-generator and a second motor-generator is disclosed. The method includes the steps of receiving an output speed, determining a kinematic output speed, and determining a slip state of the high ratio traction drive transmission based on a comparison of the output speed to the kinematic output speed.

A method of controlling a continuously variable electric drivetrain (CVED) including a high ratio traction drive transmission and at least one of a first motor-generator and a second motor-generator is disclosed. The method includes the steps of receiving an output speed, determining a kinematic output speed, and determining a slip state of the high ratio traction drive transmission based on a comparison of the output speed to the kinematic output speed.

A vehicle includes a drive axle, a multi-mode transmission, and a controller coupled to the multi-mode transmission. The multi-mode transmission includes a first gear set having a first planetary gear carrier and a second gear set having a second planetary gear carrier, a first motor/generator coupled to the first gear set, a second motor/generator coupled to the second gear set and selectively coupled to a connecting shaft, a brake positioned to selectively limit a rotational movement of a ring gear of the second gear set when engaged, a first clutch selectively rotationally coupling the first gear set and the second gear set to the drive axle when engaged, and a second clutch selectively rotationally coupling the second motor/generator to the connecting shaft when engaged. The controller is configured to engage the brake and the clutches to selectively reconfigure the multi-mode transmission to an intermediate shift mode of operation.

A vehicle includes a drive axle, a multi-mode transmission, and a controller coupled to the multi-mode transmission. The multi-mode transmission includes a first gear set having a first planetary gear carrier and a second gear set having a second planetary gear carrier, a first motor/generator coupled to the first gear set, a second motor/generator coupled to the second gear set and selectively coupled to a connecting shaft, a brake positioned to selectively limit a rotational movement of a ring gear of the second gear set when engaged, a first clutch selectively rotationally coupling the first gear set and the second gear set to the drive axle when engaged, and a second clutch selectively rotationally coupling the second motor/generator to the connecting shaft when engaged. The controller is configured to engage the brake and the clutches to selectively reconfigure the multi-mode transmission to an intermediate shift mode of operation.

A control process including the following steps is executed. The control process includes, at the time of switching from series-parallel mode to series mode, a step of reducing an engine torque, a step of releasing a clutch, a step of reducing a reaction torque of a first rotary electric machine and a step of increasing a torque of a second rotary electric machine, and, when synchronization is started and a step of increasing a positive torque of the first MG, a step of starting engagement of a clutch, and, when a rotation speed of the first rotary electric machine and a rotation speed of an engine are synchronous with each other, a step of engaging the clutch.

A control process including the following steps is executed. The control process includes, at the time of switching from series-parallel mode to series mode, a step of reducing an engine torque, a step of releasing a clutch, a step of reducing a reaction torque of a first rotary electric machine and a step of increasing a torque of a second rotary electric machine, and, when synchronization is started and a step of increasing a positive torque of the first MG, a step of starting engagement of a clutch, and, when a rotation speed of the first rotary electric machine and a rotation speed of an engine are synchronous with each other, a step of engaging the clutch.

A drive force control system for hybrid vehicles configured to reduce a change in a drive force simultaneous execution of a starting operation of an engine and a shifting operation of a transmission. The drive force control is applied to a hybrid vehicle comprising: an engine connected to front wheels; a first motor connected to rear wheels; and a transmission that changes a speed ratio between the first motor and the rear wheels. A controller restricts execution of any one of an engine staring operation and a shifting operation of the transmission during execution of other one of the engine staring operation and shifting operation of the transmission.