• The eAssist 'light electrification' system produces 25-percent increase in fuel economy
• eAssist technology is standard on all 2012 models wîth the 2.4L four-cylinder engine
• Provides customers wîth a full-size luxury sedan featuring 37 mpg highway and 25 mpg city for about $30,000 (exact pricing has not yet been set)
• Boost in fuel economy comes wîth no compromises in the driving experience
LOS ANGELES – Buick unveils the 2012 LaCrosse wîth eAssist,™ a new fuel-saving technology that increases fuel economy by 25 percent compared to the four-cylinder/six-speed powertrain in the 2011 LaCrosse. The eAssist technology provides class-leading highway fuel economy of 37 mpg, while maintaining the luxury, performance and value expected from Buick's flagship sedan. (concept carz)
The eAssist system becomes the standard powertrain on LaCrosse starting next summer. The system uses a state-of-the-art lithium-ion battery system and electric motor-generator to enable regenerative braking capability to improve LaCrosse fuel economy by an estimated 25 percent.
'The LaCrosse wîth eAssist technology is the latest example of how this successful car – wîth sales up more than 200 percent for the year – is shaking up the §egmènt and helping to reinvent Buick,' said John Schwegman, vice president of Buick marketing. 'It is the smart choice for those who want great fuel economy and performance in a luxury vehicle, wîth excellent value – the LaCrosse wîth eAssist will cost thousands less than competitors wîth similar technologies.'
Mated to a 2.4L Ecotec direct injection four-cylinder engine and next-generation six-speed automatic transmission, the eAssist system uses power stored in the battery to provide needed electrical boost in various driving scenarios, optimizing engine and transmission operation. An advanced 115V lithium-ion battery and latest-generation 15-kW motor-generator unit help increase fuel economy through:
• Regenerative braking, which provides up to 15 kW of electricity to charge the battery
• Providing up to 11 kW (15 hp) of electric power assistance during acceleration
• Automatic engine shut-off when the vehicle is stopped
• Aggressive fuel cut-off during deceleration down to zero vehicle speed, enabled by the torque smoothing provided by the motor-generator unit
• Intelligent charge/discharge of the high-voltage battery.
Buick LaCrosse wîth eAssist technology also features improved underbody aerodynamics and tires optimized for performance and fuel economy, as well as active control of front-end airflow that improves aerodynamics and engine warm-up. Electronically controlled shutters in the lower grille close at higher speeds to push more air over the vehicle, which increases aerodynamic efficiency to enhance fuel economy. All of these technologies increase the eAssist system's regenerative braking capability, while also improving the vehicle's efficiency while driving.
'LaCrosse was the first in its §egmènt wîth a four-cylinder/six-speed powertrain, the first wîth HiPer Strut and is now is leading the way wîth the new standard eAssist technology,' said Schwegman. 'Importantly, LaCrosse wîth eAssist is the standard powertrain for four-cylinder-equipped models and there isn't a cost premium.'
LaCrosse wîth eAssist includes an ECO gauge on the instrument panel that continuously responds to driving behavior, enabling the driver to drive wîth maximum efficiency. It also features a hill-assist system that captures brake pressure to help the driver more comfortably accelerate from a stop on a moderate or steep grade. It does this by greatly reducing the tendency of the vehicle to roll backward wîth the engine in shut-down mode.
eAssist details
While the eAssist system shares the same basic belt-alternator-starter configuration of previous BAS designs, it delivers more than three times the power and is much more capable than the previous-generation BAS system.
'The eAssist system is more than just the next-generation BAS system. The ability to integrate regenerative braking wîth the latest lithium-ion battery technology creates a system that delivers significant fuel-efficiency gains that customers will enjoy,' said Steve Poulos, global chief engineer of the eAssist system. 'Being able to provide electric boost to the powertrain system during heavy acceleration and grade driving enables the LaCrosse transmission to operate more efficiently, while the added functionality of engine start-stop and fuel shut-off during deceleration provides added fuel savings.'
The eAssist system's 115V air-cooled lithium-ion battery bolsters the 2.4L Ecotec four-cylinder engine wîth approximately 11 kW (15 horsepower) of electric power assist during heavy acceleration and 15 kW of regenerative braking power. That compares wîth only 2 kW of power assist and 5 kW of regenerative power on the previous BAS system. The greater power capability enables greater energy capture during regenerative braking for improved fuel economy.
The system also enables the Ecotec engine to shut down fuel delivery in certain deceleration conditions, which saves additional fuel. (concept carz) While in fuel shut-off mode, the motor-generator unit continues spinning along wîth the engine to provide immediate and smooth take-off power when the driver presses on the accelerator. Then, as the vehicle comes to a stop, the motor-generator unit spins the engine, bringing it to a smooth stop – properly positioned for a smooth restart.
'The battery system is designed to provide power assistance to the internal combustion engine, rather than storing energy for all-electric propulsion,' said Poulos. 'It's really an extension of the conventional internal combustion engine, not a replacement for it.'
The eAssist power pack contains the lithium-ion battery pack, the integrated power inverter and 12V power supply. It is located in a compartment between the rear seat and trunk; and it is surprisingly compact and lightweight, weighing only about 65 pounds (29 kg). It still allows rear access to the trunk via the split-folding rear seat – an attribute not shared wîth other hybrid competitors. Trunk space is slightly reduced when compared wîth 2011 models wîth the four-cylinder/six-speed powertrain, but still offers 10.9 cubic feet (307 liters) of storage. An electric fan cools the power pack, drawing air from a vent located in the package tray, behind the rear seat. The fans are designed to be quiet from the cabin.
The eAssist system's electric motor-generator is mounted to the engine in place of the alternator to provide both motor assist and electric-generating functions through a new engine belt-drive system. The motor-generator is a high-performance, compact induction motor that is liquid-cooled for increased performance and efficiency.
Next-generation six-speed
The eAssist system works wîth LaCrosse's direct injected 2.4L Ecotec four-cylinder and next-generation six-speed automatic powertrain combination. In the LaCrosse wîth eAssist, the engine is rated at approximately 180 horsepower (134 kW) and the next-generation Hydra-Matic 6T40 takes transmission technology to the next level wîth features designed to enhance powertrain efficiency.
Significant internal transmission changes to clutch controls and hardware provide reduced spin losses while improving shift response and time. The added electric power provided by the eAssist system allows for higher gearing to improve steady state efficiency without impacting acceleration performance or driveability. The system's capability of providing some electric assistance at cruising speeds allows the driver to accelerate lightly or ascend mild grades without the transmission downshifting.
An auxiliary, electric-driven transmission oil pump is added to the 6T40, which keeps the transmission primed and the fluid flowing when the engine shuts down at a stop. That keeps the transmission ready to perform when the driver accelerates, for a seamless, uncompromised driving experience.
'It's a very integrated powertrain system, wîth no compromises in driving performance, shift quality or ride and handling,' said Daryl Wilson, LaCrosse lead development engineer. 'We believe this combination points to the future of vehicles powered primarily by an internal combustion engine.'
Source - BuickNew V-6 Delivers Horsepower Boost to 2012 Buick LaCrosse
• Lightweight components and enhancements improve luxury sedan's performance
• 23-horsepower improvement wîth no compromise in fuel efficiency
The 2012 Buick LaCrosse, arriving in dealerships later this summer, will be available wîth a new, more powerful and fuel-efficient version of its direct-injected 3.6L V-6 engine. The engine is a no-additional-cost alternative on select trim levels to the standard 2.4L four-cylinder engine wîth eAssist.
The 3.6L V-6 wîth variable valve timing delivers a SAE-certified 303 horsepower (223 kW) on the front-wheel-drive LaCrosse – an increase of 23 hp (17 kW) – and 264 lb.-ft. (358 Nm) of torque wîth no loss in fuel efficiency (17 mpg city / 27 highway). An all-wheel-drive version, which is yet to be rated, also will be available.
'The changes we've made to the 3.6L V-6 represent greater refinements to an already well-balanced package,' said Tom Sutter, global V-6 chief engineer. 'We are using the latest designs, lighter-weight components and enhancements to improve the engine's performance, efficiency and durability.'
The lighter-weight aluminum alloy V-6 is more powerful than its predecessor partly because of its new cylinder head design, which has a revised intake port design that enhances airflow to the combustion chambers. Larger-diameter intake valves in the heads and new, longer-duration intake camshafts help provide the engine's boost in horsepower.
By using larger valves and holding them open longer, more air is pulled into the combustion chamber, for more powerful combustion. Often, the tradeoff for greater power is greater fuel consumption, but engineers optimized the fuel system for the engine's performance parameters.
'As a result, there is more power without sacrificing fuel economy,' Sutter §äid. 'The more-efficient combustion also means reduced emissions.'
The engine retains direct fuel injection, enabling greater combustion efficiency, but uses a new fuel pump and a new, isolated fuel rail. The new fuel pump is quieter, while the isolated fuel rail further reduces fuel system noise to help maintain LaCrosse's quiet-tuned operation. Direct injection also delivers reduced emissions, particularly on cold starts, where hydrocarbon emissions are cut by about 25 percent.
The new V-6 uses several lighter-weight components that help maintain LaCrosse's fuel efficiency while boosting its horsepower. The new integrated cylinder head/exhaust manifold design saves about 13 pounds compared to the cylinder heads and manifolds of the previous engine, while the new composite intake manifold saves about 5.5 pounds. Additionally, a light-weight structural front cover and lightweight, high-strength connecting rods bring the total weight savings to 20.5 pounds, improving fuel efficiency and enhancing the feeling of driving balance.
'Thanks to increased use of lightweight components and other enhancements, the new 3.6L V-6 offers 2012 LaCrosse buyers improved acceleration wîth no hit to fuel efficiency,' said Doug Osterhoff, LaCrosse product marketing manager. 'This new engine is an attractive option on the car that's been widely hailed as one of the most attractive luxury sedans on the road today.'
Source - Buick
