Background

Hybrid electric vehicles are widely accepted as a short to mid-term technical solution due to noticeably improved efficiency and lower emissions at competitive costs. Various hybrid powertrain systems have been implemented based on different styles of conventional transmission. The most widely used technology for hybridization of transmission is automated manual transmission (AMT). However, AMT is not desirable for passenger vehicles due to torque gap which results in surging clutch torch and a very bumpy ride for passengers. Server change found in the AMT further diminishes driveability.

Technology Overview

The HAMT technology provides a solution to fill torque gap by creating an independent or semi-independent torque path from the motor during gearshift. The HAMT integrates a motor, main clutch and an 8-speed parallel-shaft gearbox into one unit. The gearbox, based on a manual gearbox, has three connection ports which are connected to an engine via a main clutch, motor and final drive (Figure 1). Through thoughtful combinations of actuators inside the gearbox, this novel solution provides agile operation and achieves desirable drivability and fuel economy. The HAMT model also supports full EV mode.

Stage of Development

A Simulink-Sim Driveline hybrid vehicle model, based on powertrain system component models extracted from AUTONOME simulation tool, was built with all new transmission and driveline. Control strategy was built to harmonically coordinate different powertrain components to realize TGF function. A vehicle launch simulation test is finished under 30% of accelerator pedal position to thoroughly reveal details during gearshift. Simulation results revealed that this HAMT can eliminate most torque gaps that have been a persistent issue of traditional AMT, leading to improved drivability and performance.

Benefits

Benefits:

• Eliminates issues with torque gap during gear shift
• Takes advantage of pre- and post- transmission parallel hybrid configurations
• Integrates a motor, main clutch and an 8-speed parallel-shaft gearbox into one unit
• Provides agile operations, desirable driveability and fuel economy

Applications

Hybrid vehicles and vehicles that support full EV mode

Opportunity

Opportunities:

· Collaborative research

· Technology licensing