Turner Powertrain development of the PG115 Lock-up transmission was born of research that identified the need to provide a more energy efficient solution for the application of the PG115 transmission in machines. Customer research identified improved fuel efficiency as a key requirement and that fuel efficiency is a significant differentiator between machines in a purchasing decision. After an investigation of the energy usage over the machines application profile it was identified that the greatest energy losses were made during traveling between work sites.
Investigation of the energy losses found that much of the loss could be traced to the torque converter. Specifically identified was the fluid coupling slippage as the main energy loss and that a solution would be a torque converter which was capable of initiating direct or lock-up clutch drive.
The engineering team developed a torque converter containing a clutch mechanism for the specific purpose of controlling and initiating direct drive. They also investigated how a transmission could be adapted to include a system to control the internal torque converter clutch mechanism, using software control of an electrically actuated hydraulic valve that redirected oil flow within the transmission to feed the torque converter clutch mechanism and provide a controllable oil pressure.
A test transmission was manufactured to prove the design and test functionality. The positive results achieved from this test model convinced the team that further proof of design transmissions should be developed to provide further models for laboratory testing and to test in machines. Further development work revised and improved the functioning of the transmission and the lock-up clutch torque converter and prepared the product for serial manufacture.
A number of transmissions were released for pilot production on the production line. These transmissions proved that serial production systems were capable of producing repeatable product and provided further transmissions for field machines to provide further validation data. The PG115 lock-up transmission proved to work successfully throughout the testing phase and therefore was introduced to the market. It was first adopted by Caterpillar as an option for their back hoe loader and has since been adapted to be used for Hidromek in their back–hoe loader machine and further adapted for rail applications. The system has the potential for further development to be adapted to other machine applications. Further details of this transmission can be found here.