GM 2 Mode Transmission
GM has simplified the two-mode hybrid system for application in front-wheel drive vehicles—the Saturn VUE being the first instance —while retaining its functionality and capability,
The RWD version of the two-mode used to power the full-size SUV and pickup hybrid models incorporates two motors, three planetary gearsets and four clutches. The resulting system offers two electric continuously variable transmission (ECVT) modes (low and high speed) and also incorporates four fixed-gear ratios for high efficiency and power-handling capabilities in a broad variety of vehicle applications, including towing.
The 2-Mode Hybrid Transmission contains two electric motors, 3 planetary gear sets, and 4 wet-plate clutches. The hybrid transmission can operate in multiple modes including propelling the vehicle electrically with the combustion engine off. Two continuous ratio modes of operation are attained with the electric motors, one with the combustion engine supplying torque, and the other with an electric motor supplying torque. Since the continuous ratio ability is attained with one of the electric motors, these modes are described as Electrically Variable Transmission modes or “EVT†modes. Three 300 volt A/C cables are connected to each of the two motors, these cables attach to the transmission housing via a rigid conduit around the transmission and are connected to an inverter which drives the motors. Simple!!!
The system was also introduced for the 2008 model year in the full-sized Chevrolet Tahoe and GMC Yukon SUVs as a specific 2-Mode Hybrid model.It is available in both two and four wheel drive models. GM will reportedly offer an identical 2-mode hybrid system in its full-size 2009 model 1/2-ton pickup trucks.
The immediate results look good. Only the test of time will show us how durable they are. I never buy anything in it’s first year of production, I don’t want to be a guinea pig. Let them work out the bugs first. Realistically, conventional automatic transmissions will here for a while meaning that the maintenace procedures we recommend for them apply. What will the care of a hybrid transmission be? We don’t know yet. As we get this info it will be posted for your information.
With the preponderance of transmissions being conventional in design, GotTransmission.com is the most qualified supplier of transmissions in the country. We use our GotTransmissions.com Blog to help keep you informed on new transmission technology and real world information on current transmissions. Knowing the economy is in a mess for a while means more folks will be replacing broken transmissions than replacing cars with broken transmissions. It only makes sense, call us at 866-320-1182 for any questions you may need answered or use our comment box.
