When needed, the belt alternator starter hybrid will also provide an electric power assist during acceleration. During a wide-open throttle or aggressive passing maneuver, the system improves vehicle launch and acceleration feel by assisting the engine to achieve maximum power.
The system is designed to automatically maintain accessory functionality and passenger comfort when the engine is stopped, Nitz says, which means that the vehicle's hybrid operation will go unnoticed by the driver and passengers.
The belt alternator starter hybrid consists of six major components:
Stephens notes that GM's belt alternator starter hybrid operates in either the motoring or generating mode.
In the motoring mode, the belt alternator starter hybrid is used to quickly restart the engine upon brake pedal release and to provide momentary acceleration assist as needed.
"To perform these functions," Stephens explains, "the advanced nickel metal hydride hybrid battery converts its stored chemical energy into direct current electrical energy. The hybrid's power electronics then convert the DC electrical energy to three-phase alternating current to run the motor/generator unit as a motor. Vehicle accessory power is also generated in this mode."
In the generating mode, Stephens adds, the belt alternator starter hybrid is used to provide both 12V vehicle accessory power and power to recharge the hybrid battery.
"To perform these functions," he says, "the engine is used to power the motor/generator unit, which then provides a three-phase electrical output. In this mode, the energy required to drive the engine may come from either gasoline when accelerating, or the kinetic energy of the moving vehicle when decelerating with the fuel cut off. The three-phase AC electrical output of the motor/generator is then converted to DC electrical outputs by the power electronics that are, in turn, used to efficiently charge both the hybrid and vehicle accessory batteries."
Stephens says GM's hybrid strategy is part of GM's larger overall advanced propulsion technology strategy, which is focused on introducing new technologies to improve the internal combustion engine and transmissions to further reduce vehicle emissions and increase fuel economy.
"We want to provide consumers a choice that will be in harmony with their budget, vehicle expectations and fuel economy needs," says Stephens. "The belt alternator starter hybrid will offer consumers the combination of an affordable price and a good fuel economy improvement over the base vehicle."
photo:General Motors
The system is designed to automatically maintain accessory functionality and passenger comfort when the engine is stopped, Nitz says, which means that the vehicle's hybrid operation will go unnoticed by the driver and passengers.
The belt alternator starter hybrid consists of six major components:
- precision electric motor/generator unit
- engine coolant-cooled power electronics that control the motor/generator unit and provide 12-volt vehicle accessory power
- an advanced, nickel metal hydride hybrid battery pack capable of delivering and receiving more than 10kW of peak power
- an engine control module that includes "sophisticated Hybrid Supervisory Software" to manage both engine and hybrid system operation
- a new engine accessory drive with dual tensioner assembly and aramid cord belt that enables reliable transfer of both motoring and generating torque, and
- the hybrid-enabled 4T45-E transaxle that includes an auxiliary oil pump and unique hybrid controls to ensure seamless hybrid operation.
Stephens notes that GM's belt alternator starter hybrid operates in either the motoring or generating mode.
In the motoring mode, the belt alternator starter hybrid is used to quickly restart the engine upon brake pedal release and to provide momentary acceleration assist as needed.
"To perform these functions," Stephens explains, "the advanced nickel metal hydride hybrid battery converts its stored chemical energy into direct current electrical energy. The hybrid's power electronics then convert the DC electrical energy to three-phase alternating current to run the motor/generator unit as a motor. Vehicle accessory power is also generated in this mode."
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| (Photo: General Motors) |
"To perform these functions," he says, "the engine is used to power the motor/generator unit, which then provides a three-phase electrical output. In this mode, the energy required to drive the engine may come from either gasoline when accelerating, or the kinetic energy of the moving vehicle when decelerating with the fuel cut off. The three-phase AC electrical output of the motor/generator is then converted to DC electrical outputs by the power electronics that are, in turn, used to efficiently charge both the hybrid and vehicle accessory batteries."
Stephens says GM's hybrid strategy is part of GM's larger overall advanced propulsion technology strategy, which is focused on introducing new technologies to improve the internal combustion engine and transmissions to further reduce vehicle emissions and increase fuel economy.
"We want to provide consumers a choice that will be in harmony with their budget, vehicle expectations and fuel economy needs," says Stephens. "The belt alternator starter hybrid will offer consumers the combination of an affordable price and a good fuel economy improvement over the base vehicle."
photo:General Motors
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