GM revealed today, ahead of 2010 Los Angeles Auto Show in California, the 2012 Buick LaCrosse with eAssist, a new fuel-saving technology that promises to increase fuel economy by 25 percent when comparing it with the already fuel-efficient four-cylinder/six-speed powertrain in the 2011 LaCrosse. According to the auto manufacturer, the new eAssist technology will deliver an impressive class-leading highway fuel economy of 37 mpg.
Ok, so what is so special about this technology? Well, according to GM, the eAssist features the same basic belt-alternator-starter configuration of previous BAS designs, but delivers more than three times the power and is much more capable than the previous-generation BAS system.
The new 2012 Buick LaCrosse is powered by a 2.4-liter Ecotec four-cylinder engine, but the eAssist system’s 115V air-cooled lithium-ion battery bolsters its power with approximately 11 kW (15 horsepower) of electric power during heavy acceleration and 15 kW of regenerative braking power.
To note, the older version of the BAS system delivered only 2 kW of power assist and 5 kW of regenerative power. Furthermore, the new system can also down fuel delivery in certain deceleration conditions.
The eAssist power pack uses a lithium-ion battery pack -- the integrated power inverter and 12V power supply -- located in a compartment between the rear seat and trunk. The battery pack which has a total weight of about 65 pounds (29 kg), reduced the trunk space to 10.9 cubic feet (307 liters) of storage.
In addition, a new electric fan cools the power pack, drawing air from a vent located in the package tray, behind the rear seat. The eAssist’s electric motor-generator is mounted to the engine in place of the alternator. The new car also comes with a new Hydra-Matic 6T40 six-speed automatic transmission. This means that the total output of the 2012 Buick LaCrosse is rated at 180 hp (134 kW).
Power is sent to the wheels through the next generation of the Hydra-Matic 6T40 gearbox, which takes transmission technology to the next level with features that can enhance enhance powertrain efficiency. For instance, the Hydra-Matic 6T40 gearbox now boasts of reduced spin losses while improving shift response and time.
Thanks to the added electric power provided by the eAssist system, higher gearing can be achieved, thereby improving steady state efficiency without negatively affected acceleration performance or drivability.
Moreover, the new Hydra-Matic 6T40 gearbox now features an auxiliary, electric-driven transmission oil pump that can keep the transmission system primed and the fluid flowing when the engine shuts down during a stop. This means that the transmission is always to work as soon as the driver accelerates.