As Bosch announced another application of its stop-start system—on the Fiat 500, it also stated that it anticipates half of all new vehicles in Europe will incorporate the technology by 2012.
The 500 is the first Fiat to use stop-start, which Bosch estimates can typically reduce fuel consumption by up to 5% on the NEDC (New European Driving Cycle). In the urban cycle of the NEDC, the saving can be as high as 8%.
Bosch supplies a specially adapted starter, engine management system, and battery sensor. It began manufacturing stop-start systems in 2007 and has revealed that it has delivered more than 500,000 starters to BMW and Mini.
Stefan Asenkerschbaumer, President of Bosch's Starter Motors and Generators Division, believes that, as automotive emissions requirements tighten, the stop-start market is set to expand widely and rapidly.
"In 2008, roughly 5% of all new vehicles in Europe are equipped with a stop-start system," he said. "By 2012, we estimate this will be in every second newly registered vehicle—most of them with Bosch technology." Kia is scheduled to shortly introduce a Bosch stop-start system on the Cee’d.
Typically, a stop-start system facilitates an engine restart as soon as the driver depresses the clutch pedal to put the vehicle back into gear. As starter-based systems are largely based on existing components, their cost-benefit ratio is excellent, says Bosch, and unlike other technologies, this approach is also suitable for cold starts in diesel engines.
For the Fiat 500, though, the system will initially be available in combination with the Dualogic automated manual transmission and a 1.2-L engine. In this application, the engine restarts when the foot brake is released. Fiat plans to install the system in other variants and models in 2009.
Bosch has adjusted the service life of the starter to cope with the greatly increased number of starts associated with the system. The electric starter motor has been developed to achieve low noise levels, and the company explains that enhanced meshing mechanics guarantee safe, fast, and quiet engine starts in all situations.
Bosch also supplies the engine control unit (ECU) and battery sensor for the Fiat 500. The ECU includes the software used to analyze all the relevant sensor data and to stop and start the engine. The battery sensor computes the current state of battery charge and relays information to the energy management system.
As well as the starter, control software, and battery sensor, the Fiat’s stop-start system comprises a crankshaft sensor and pedal sensors. A high-efficiency alternator, in combination with a deep-cycle resistant battery, increases the vehicle’s engine-off time capability.