A leader in vehicle fuel economy improvement technology, Valeo is offering Original Equipment Manufacturer (OEM) customers two micro-hybrid systems – i-StARS and ReStart. Both solutions enable stop-start functionality and can help reduce the fuel consumption of a traditional internal combustion engine by two-to-three percent during the standard driving cycle and by up to 15 percent in congested urban traffic.
“The two solutions are part of a complete family of cost-effective stop-start system technologies,” said Valeo Group Product Marketing Director Derek de Bono. “The stop-start function automatically stops the engine when the vehicle is stationary. The i-StARS starter-alternator and the ReStart reinforced starter make it possible for the engine to immediately restart.”
i-StARS: A Two-For-One Technology
Valeo’s i-StARS, which stands for integrated Starter Alternator Reversible System, is a stop-start system based on a combined starter-alternator solution replacing the conventional alternator. Similar to an alternator, it is linked to the crankshaft through the belt drive. i-StARS enables the combustion engine to shut off when the driver begins to brake and the vehicle has dropped below a preset speed. For example, one Valeo application example in the market today stops the engine when the vehicle speed drops below five miles per hour (eight km/h) for automatic transmissions and below 13 miles per hour (20 km/h) for manual transmissions. i-StARS automatically restarts the engine in approximately 400 milliseconds, even when drivers unexpectedly change their minds during stopping sequences.
i-StARS is a 14-volt LIN-interfaced, belt-driven starter-alternator with integrated electronics that is scalable up to eight kW. Compared to previous product generations, the advanced design provides increased torque and reliability, while improving cost, packaging and temperature management. In addition to LIN, it can interface with any OEM engine control unit architecture, such as RVC and C-Terminal.
As the vehicle’s alternator, i-StARS’s power electronics improve the system’s electrical efficiency to make it one of the most efficient alternators on the market. The integrated control and power electronics reduce system cost and makes it easier to install during vehicle assembly. The i-StARS+ version is a seven-phase design, making it extremely quiet, giving it best-in-class noise performance. It can be applied to up to 4-liter gasoline and 3-liter diesel engines and easily adapts to both manual and automatic transmissions.
The i-StARS belt drive provides excellent comfort performance, enabling a faster and smoother engine stop with less oscillations and a smooth and silent restart. Ready for automatic transmission applications, the innovation’s belt drive offers greater stop-start functionality by making it possible to restart an engine while the flywheel is still rotating or the gear is still engaged. Allowing the engine to stop before the vehicle does, maximizes the fuel economy benefits of a vehicle coasting to a stop. This unique capability makes it ideal for the United States market, where more than 90 percent of vehicles are equipped with automatic transmissions and drivers expect smooth and silent start-stop operation.
ReStart: The Starter-Based Solution
Valeo’s ReStart system is the second solution in the company’s range of stop-start innovations. This reinforced starter provides the extra durability needed for repeated stopping and starting when the vehicle comes to a complete standstill. ReStart has minimal impact on engine architecture and can be applied to a variety of engine types and displacements.
Currently, Valeo is developing a reinforced starter capable of restarting an engine, while it is still rotating, for automatic transmissions and to offer additional fuel economy improvement.
A History of Hybridization
Valeo provides a full range of vehicle electrification solutions, from full electric to micro-hybrids. The company launched its first belt-driven starter generator on the Citroen C3 in 2004 and programs with Mercedes, Nissan and PSA soon followed.
“During the United States CAFE urban test cycle, a car is idle about 19 percent of the time or 10 percent for combined highway/city operation,” said de Bono. “Makingautomatic engine shut-down and restart more affordable is a viable near-term solution to reducing vehicle CO2 emission and improving fuel economy.”
Valeo’s experience in reversible belt-driven machine design is a valuable asset in its development of higher-voltage belt-driven systems for mild hybrid applications. Its next generation of systems will have the ability to recover braking energy and provide engine torque assistance.
Valeo is an independent industrial Group fully focused on the design, production and sale of components, integrated systems and modules for the automotive industry, mainly for CO2 emissions reduction. Valeo ranks among the world’s top automotive suppliers. The Group has 125 plants, 21 research centers, 39 development centers, 10 distribution platforms and employs 67,900 people in 28 countries worldwide.
In North America, Valeo’s regional headquarters is located in Troy, Mich., and the company has 15 production sites and six research and development centers. The company employs approximately 6,200 people across the United States and Mexico and was responsible for 13 percent of the Group’s 2010 global annual sales.
The company’s innovative solutions are developed by its four business groups – Comfort and Driving Assistance Systems, Powertrain Systems, Thermal Systems, Visibility Systems – and Valeo Service. Valeo’s key products support and advance automotive electrical systems; transmission systems; engine management systems; air management systems; hybrid and electric vehicle systems; climate control; powertrain thermal systems; compressors; front-end modules; driving assistance; interior controls; interior electronics; access mechanisms; lighting systems; wiper systems; and, wiper motors.
More information about the Valeo Group and its activities can be found on the Internet at www.valeo.com