Abstract: A hydraulic control system for distributing pressurized fluid to a multi-mode hybrid-type power transmission is provided, as well as a method for regulating the same. The hydraulic control system includes an engine-driven main pump in fluid communication with a main regulator valve, and an electrically-driven auxiliary pump in fluid communication with an auxiliary regulator valve. One pressure control solenoid provides feedback (boost) pressure to both regulator valves, and thereby modify output of the main and auxiliary pumps. A controller selectively modifies distribution of boost pressure to ensure a continuous and controllable feed of hydraulic pressure to the transmission during all vehicle operations.

Abstract: A method and an apparatus for controlling an electro-mechanical transmission selectively operative in a plurality of fixed gear modes and continuously variable modes is provided. The exemplary transmission comprises first and second electrical machines and a hydraulic circuit comprising a plurality of pressure control devices and flow management valves. The method comprises monitoring an operating temperature of the electrical machines. A cooling flow rate in the hydraulic circuit effective to reduce the operating temperature of the electrical machines is determined. Availability of active cooling for each of the electrical machines is determined. Hydraulic flow in the hydraulic circuit is selectively controlled.

Abstract: A method for controlling an electromechanical transmission includes monitoring a current hydraulic circuit oil temperature, monitoring a current state of flow management valves, monitoring a command for cooling of electric machines, monitoring a desired transmission operating range state, utilizing a state machine to determine a sequence for controlling positions of the flow management valves to achieve the desired transmission operating range state based upon the monitored properties.

Abstract: A method for controlling a hydraulic flow within a powertrain comprising an electromechanical transmission mechanically-operatively coupled to an engine adapted to selectively transmit power to an output, wherein the transmission utilizes a hydraulic control system serving a number of hydraulic oil consuming functions includes monitoring minimum hydraulic pressure requirements for each of the functions, determining a requested hydraulic pressure based upon the monitoring minimum hydraulic pressure requirements and physical limits of the hydraulic control system including a maximum pressure, determining a desired flow utilizing a hydraulic control system flow model based upon the requested hydraulic pressure, and utilizing the desired flow to control an auxiliary hydraulic pump.

Abstract: The present invention provides a control system employing a single solenoid valve operable to provide a variable fluid flow to effect cooling if the motor/generator assemblies contained within an electrically variable hybrid transmission. The control system of the present invention selectively controls the cooling of at least one motor/generator assembly of an electronically variable hybrid transmission by selectively controlling valves of various types and configurations.

Abstract: An electromechanical transmission includes a rotor supported by a rotor hub that has at least one passage formed therein for providing cooling fluid flow to the rotor. Preferably, cooling fluid is provided to the passage through an orifice to control flow rate. An inner diameter of the rotor is supported by the rotor hub and fluid is pooled by the rotor hub opposite the rotor inner diameter for cooling thereof. Preferably, fluid is thrown by centrifugal force from the rotor hub onto rotor ends and then onto an inner diameter side of stator windings of a stator surrounding the rotor. A method of cooling an electromechanical transmission is also provided.

Abstract: An assembly and method is provided for reducing clutch wear due to centrifugal apply pressure within a clutch-apply cavity. The assembly comprises a rotatable clutch housing, a clutch-apply piston disposed within a clutch-apply cavity, and a balance piston. The balance and apply pistons define a balance cavity including a liquid fill channel and a dedicated air exhaust channel having a control radius configured to at least partially offset or compensate for the centrifugal apply force generated within the clutch-apply cavity when the clutch assembly rotates. The method includes configuring the balance cavity with an exhaust channel for exhausting fluid, and providing the exhaust channel with a control radius determined by the innermost radius of rotating fluid within the balance cavity as measured with respect to the centerline of rotation of the clutch assembly, the control radius being suitable for exhausting any excess of centrifugal balance force over centrifugal apply force.

Abstract: A powertrain has an electrically variable hybrid transmission having an electro-hydraulic control system, plurality of electrical power units, and a plurality of torque transmitting mechanisms selectively engageable by the electro-hydraulic control system to provide four forward speed ranges, a neutral condition, an electric low and high speed mode, and an electrically variable low and high speed mode. Additionally, the electrically variable hybrid transmission provides a parallel reverse mode and a series reverse mode. The present invention provides an improved electro-hydraulic control system having a multiplexed electronic transmission range selection (ETRS) and reverse dog clutch system for an electrically variable hybrid transmission. The multiplexed control system of the present invention allows effective control of both the ETRS system and reverse dog clutch system using only one solenoid valve.

Abstract: A powertrain has an electrically variable hybrid transmission having an electro-hydraulic control system, plurality of electrical power units, and a plurality of torque transmitting mechanisms selectively engageable by the electro-hydraulic control system to provide four forward speed ranges, a neutral condition, an electric low and high speed mode, an electrically variable low and high speed mode, and a hill hold mode. The electro-hydraulic control system includes a multiplexed pressure switch system. The multiplexed pressure switch system of the present invention allows position detection of six torque transmitting mechanism control valves through the use of only four pressure switches.

Abstract: A method and apparatus to control an electrically variable transmission, by dynamically controlling system main hydraulic clutch pressures, based upon required clutch capacity, as determined by output load of the transmission. Included is a method to regulate hydraulic clutch pressure in an electrically variable transmission equipped with at least one clutch. This comprises monitoring magnitude of slippage of the clutches and controlling hydraulic boost pressure based upon the magnitude of clutch slippage. Controlling hydraulic boost pressure based upon the magnitude of clutch slippage comprises monitoring operator inputs, determining a requested operator torque command, and determining a required main boost pressure. The main boost pressure is based upon the requested operator torque command, the monitored operator inputs, parameters of the EVT and clutches. Commanded main boost pressure is then determined based upon the determined required main boost pressure.

Abstract: A method and an apparatus for controlling an electro-mechanical transmission selectively operative in a plurality of fixed gear modes and continuously variable modes is provided. The exemplary transmission comprises first and second electrical machines and a hydraulic circuit comprising a plurality of pressure control devices and flow management valves. The method comprises monitoring an operating temperature of the electrical machines. A cooling flow rate in the hydraulic circuit effective to reduce the operating temperature of the electrical machines is determined. Availability of active cooling for each of the electrical machines is determined. Hydraulic flow in the hydraulic circuit is selectively controlled.

Abstract: A powertrain has an electrically variable hybrid transmission having an electro-hydraulic control system, plurality of electrical power units, and a plurality of torque transmitting mechanisms selectively engageable by the electro-hydraulic control system to provide four forward speed ranges, a neutral condition, an electric low and high speed mode, an electrically variable low and high speed mode, and a hill hold mode. The electro-hydraulic control system permits operation in the electrically variable low mode of operation if the electrical power is interrupted when the powertrain is operating in the first forward range, electric low speed mode, electrically variable low speed mode, and hill hold mode. Additionally, the system permits operation in the electrically variable high speed mode of operation if the electrical power is interrupted when the powertrain is operating in the second through fourth forward range, electric high speed mode, and electrically variable high speed mode.

Abstract: A powertrain has an electrically variable hybrid transmission having an electro-hydraulic control system, plurality of electrical power units, and a plurality of torque transmitting mechanisms selectively engageable by the electro-hydraulic control system to provide four forward speed ranges, a neutral condition, an electric low speed mode, an electrically variable low and high speed mode, and two electrical power off drive home modes. The electro-hydraulic control system includes a multiplexed pressure switch system. The multiplexed pressure switch system of the present invention allows position detection of five torque transmitting mechanism control valves through the use of only four pressure switches.

Abstract: A powertrain has an electrically variable hybrid transmission having an electro-hydraulic control system, plurality of electrical power units, and a plurality of torque transmitting mechanisms selectively engageable by the electro-hydraulic control system to provide four forward speed ranges, a neutral condition, an electric low speed mode, an electrically variable low and high speed mode, and two electrical power off drive home modes. The electro-hydraulic control system of the present invention has a multiplexed trim system for an electrically variable hybrid transmission. The multiplexed trim system allows engagement control of four torque transmitting mechanism and individual control of fluid flow to effect cooling of two motor/generators by multiplexing three trim valves with two logic valves.

Abstract: The present invention provides a multiplexed control system, employing a single solenoid valve, to selectively control the damper lock-out clutch and motor/generator cooling of an electronically variable hybrid transmission. The present invention also contemplates a method of selectively controlling damper lock-out clutch engagement and motor/generator cooling for an electrically variable hybrid transmission control.

Abstract: A method and apparatus for efficiently cooling and lubricating rotating components in a hybrid transmission is provided. By efficiently managing cooling flow to and between the rotating elements, flow requirements and associated pumping requirements within the drive unit are minimized. In addition, by providing a method for placing the fluid directly on the required components, spin losses associated with component contact with stray oil are reduced. Combined, the reduction in pumping and spin losses create a more efficient drive unit and an overall more efficient hybrid drive system which directly leads to higher fuel economy.

Abstract: A method for providing an active engine stop of the engine of a hybrid electric vehicle. The method utilizes the electric machine to oppose and rapidly stop the rotation of the engine at a controlled rate. The method includes the calculation of an input speed reduction trajectory using the engine speed when the active engine stop request is made and a predetermined speed reduction interval. The speed reduction interval is less than a time from the active stop request to the shutoff command to the electric machine The method provides rapid deceleration of the engine, particularly through the powertrain resonance speed, reducing the amount of vibration energy dissipated through the powertrain and chassis. The method removes the electric machine torques from the engine prior to achieving zero engine speed in order to avoid imparting a negative engine speed or counter-rotation of the engine.

Abstract: The normal control of an electrically-activated hydraulic valve armature is overridden to automatically and periodically open the armature for flushing out debris that has accumulated between the armature and a seat that the armature is designed to engage. The valve develops fluid pressure for maintaining engagement of a motor vehicle transmission clutch, and when excessive slippage of the clutch is detected, the armature is forced into engagement with the seat until the slippage is reduced or a predetermined period of time has elapsed, after which the armature is temporarily positioned away from the seat to provide full flow of hydraulic fluid across the seat to flush out debris that prevents the armature from engaging the seat. During Neutral operation of the transmission, the armature is continuously positioned away from the seat, and during low torque conditions the armature is temporarily positioned away from the seat.

Abstract: The present invention is drawn to a method and apparatus for cooling a hybrid transmission electric motor. More precisely, an annular chamber is formed between a housing for the electric motor and a transmission housing. Coolant is disposed in the annular chamber and is applied to the electric motor through a plurality of coolant apertures in the motor housing to cool the motor.

Abstract: Hydraulic fill and drain of a clutch chamber is controlled with a blocking valve and a trim valve. The blocking valve selectively provides pressurized fluid to the trim valve which in turn selectively provides the pressurized fluid to the clutch chamber. Exhausting of the clutch chamber is effected through one of two alternate paths utilizing deactivation of one of the trim and blocking valves. Back up exhausting of the clutch chamber is effected through the other of the alternative paths. Such system allows for determination of valve failures and continued operation until such failures can be rectified.