A powertrain may include a plurality of shafts disposed in parallel with a transmission input shaft of a first shifting mechanism which receives power from an engine, and transmitting power from a motor to a driving shaft while a vehicle is driven; and a second shifting mechanism including a plurality of gears fitted on the shafts, in which one of the gears remains engaged and rotated as a driven gear by a constant synchronizer while the vehicle is driven.

A hybrid vehicle includes an electronic control unit configured to: set a target rotation speed of an engine based on a vehicle speed and a shift position; set a driving force when an upper-limit power is output to a drive shaft as an upper-limit driving force; set a target engine power such that the smaller of the upper-limit driving force and the required driving force is output to the drive shaft; and control the engine, the first motor, and the second motor such that the engine to rotate at the target rotation speed and to output the target power. At this time, the upper-limit power is set to be lower when a coolant temperature of the engine is low than when the coolant temperature is high.

When a kickdown switch is turned off, a target rotation speed of an engine is set on the basis of a vehicle speed and a gear and the engine, the first motor, and the second motor are controlled such that the smaller driving force of an upper-limit driving force based on the target rotation speed and a required driving force is output to a drive shaft and the engine rotates at the target rotation speed. On the other hand, when the kickdown switch is turned on, the target rotation speed is set to be higher than that when the kickdown switch is turned off on the basis of the vehicle speed and the gear and the engine, the first motor, and the second motor are controlled such that the required driving force is output to the drive shaft and the engine rotates at the target rotation speed.

A dual-motor power system or a dual-motor hybrid power system for a vehicle comprises a first motor, a second motor, an intermediate shaft, a first gear set disposed between a first driving shaft, and an intermediate shaft. The first driving shaft couples with the intermediate shaft via the first gear set, a second gear set disposed between the second driving shaft and the intermediate shaft, and a single synchronizer disposed around the second driving shaft. The synchronizer can be switched between a neutral position, a first-speed-ratio position, and a second-speed-ratio position. In the neutral position, the second driving shaft is decoupled from the first and second gear sets. In the first-speed-ratio position, the synchronizer couples the second driving shaft with the intermediate shaft via the first gear set. In the second-speed-ratio position, the synchronizer couples the second driving shaft with the intermediate shaft via the second gear set.

A method is provided to control a hybrid powertrain comprising an internal combustion engine; a gearbox with input and output shafts; a range gearbox, connected to the output shaft; a first planetary gear, connected to the input shaft; a second planetary gear, connected to the first planetary gear; a first electrical machine, connected to the first planetary gear; a second electrical machine, connected to the second planetary gear; at least one gear pair, connected with the first planetary gear and the output shaft; and at least one gear pair, connected with the second planetary gear and the output shaft, wherein the internal combustion engine is connected with the first planetary gear via the input shaft. The method comprises the steps: a) engaging a gear by way of connecting two rotatable components in the first planetary gear; b) connecting the at least one gear pair, connected with the second planetary gear and the output shaft; c) connecting a sixth gear pair, arranged between a countershaft and the range gearbox with the countershaft, so that the countershaft is connected with the output shaft via the range gearbox; d) controlling the range gearbox from a low range position to a neutral state, in which no torque transmission occurs through the range gearbox; e) controlling two rotatable components in the range gearbox towards achieving a synchronized rotational speed with the assistance of the first electrical machine; f) connecting the rotatable components with the use of a shiftable third clutch device; and g) engaging a gear by way of connecting two rotatable components in the second planetary gear.

Provided is a method to control a hybrid powertrain to achieve a reverse drive, wherein the hybrid powertrain comprises an internal combustion engine; a gearbox with an input and output shaft; a first planetary gear connected to the input shaft and a first main shaft; a second planetary gear connected to the first planetary gear and a second main shaft; first and second electrical machines respectively connected to the first and second planetary gears; one gear pair connected with the first main shaft and the output shaft; and one gear pair connected with the second main shaft and the output shaft, wherein the internal combustion engine is connected with the first planetary gear via the input shaft. The method comprises: ensuring that moveable component parts in the first planetary gear are disconnected from each other and/or that moveable component parts in the second planetary gear are disconnected from each other; ensuring that an output shaft in the internal combustion engine is prevented from rotating; and controlling the first electrical machine and/or second electrical machine to achieve a negative torque in the output shaft via the first main shaft and/or second main shaft.

A transmission for a vehicle includes a first input shaft installed to receive power from an engine, a second input shaft concentrically disposed with the first input shaft and installed to receive power from a motor, an output shaft disposed in parallel with the first input shaft and the second input shaft, a first synchronizer provided at the first input shaft to selectively connect the first input shaft and the second input shaft, a first stage driving gear and a second stage driving gear provided at the second input shaft, a first stage driven gear and a second stage driven gear disposed at the output shaft to be freely rotated and meshed with the first stage driving gear and the second stage driving gear, respectively, to form a first stage shift ratio and a second stage shift ratio, and a second synchronizer installed to selectively connect any one of the first stage driven gear and the second stage driven gear with the output shaft.

A power transmission system of hybrid electric vehicle includes an input shaft, counter shaft, an output shaft, first motor/generator, second motor/generator, first planetary gear set, second planetary gear set to selectively externally gear-connect fourth rotation element to third rotation element through counter shaft while being directly connected to counter shaft and to directly connect fifth rotation element to output shaft and selectively connect sixth rotation element to transmission housing, first transfer gear disposed between second rotation element and output shaft, second transfer gear disposed between third rotation element and counter shaft, variable direct connection device to selectively connect two of three rotation elements of second planetary gear set, and variable connection device to selectively connect sixth rotation element to transmission housing or selectively external gear-connect third rotation element to fourth rotation element.

The present invention relates to a hybrid transmission using an engine and two electric motors/generators together, wherein a planetary gear device comprising double planet gears, two sun gears and a ring gear, as a power splitter is used, and in addition, to a hybrid transmission in which one or more clutches and/or one or more brakes are combined to select a mechanical shift mode other than a hybrid mode and an electric drive mode.

Disclosed is a hybrid work vehicle capable of smooth work travel using a work device with a low output internal combustion engine, while avoiding battery exhaustion. The vehicle includes an internal combustion engine that supplies drive power to a travel device and a work device via power transmission means, a motor generator that is driven by a battery, a load information generation part that generates load information representing a sudden increase in rotational load, an assist characteristic determination part that determines motor assist characteristics defining an assist amount and an assist time period of assist control based on load information, and a motor control unit that controls the motor generator based on the motor assist characteristics.