Hybrid systems offer automotive savings

Bosch has confirmed that the fuel consumption of automotive vehicles can be dramatically reduced with hybrid technology, especially in city traffic.

Bosch has confirmed that the fuel consumption of automotive vehicles can be dramatically reduced with hybrid technology, especially in city traffic.

This is largely thanks to the electric motor installed in mild and strong hybrids, which also makes for greater driving dynamics and more driving fun.

The hybrid systems offered by Bosch can be divided into three functional categories: micro hybrids including start/stop function, mild hybrids with boost effect, and strong hybrids which allow for driving with electrical energy over short distances.

In the micro hybrid category, Bosch banks mostly on the cost efficient smart electronic start/stop system, which works with a reinforced starter.

The system requires minimum modification input for existing vehicles, which offers a chance for deployment in large unit numbers in the near future.

In city traffic, vehicles more often than not are stopped by traffic lights or simply due to traffic congestion.

On occasions such as this, the Bosch Micro Hybrid System is designed to automatically shut off the engine.

In order to move off again, the driver simply steps on the clutch pedal for the system to restart the engine both quickly and conveniently.

The use of the start/stop system may increase fuel efficiency by as much as 8%.

Production of the Micro Hybrid System smart electronic start/stop is planned for 2006.

Both mild and strong hybrids offer the same benefits as the micro hybrid system, though mild hybrids are equipped with an electric motor of up to 25kW output.

This relatively small power motor offers additional acceleration when overtaking another vehicle, providing a "boost" effect.

Combined with a traditional combustion engine, the energy saved can reduce fuel costs by up to 15%.

The same can also be said for the strong hybrid, though it is equipped with a stronger power motor of up to 75kW, and in some cases more.

This results in a greater torque of up to 400Nm from standstill, as well as potential fuel savings of more than 20% on average.

The system also allows for driving shorter distances with just electrical power and therefore zero emissions.

Bosch relies on its own production of permanent-magnet synchronous motors powered by a high-voltage battery to run its high-power electrical drives.

Bosch expects, on the basis of present calculations, about 100kg of additional weight in a strong hybrid vehicle compared with a conventional petrol-powered vehicle.

Technically the components for hybrid drives such as high-power batteries, electric motors and DC/DC convertor may well find their way into the design of fuel cell vehicles currently under development.

Bosch has been involved with hybrid technologies for more than 30 years.

No other supplier to the automotive industry boasts such a broad knowledge base with knowhow in petrol and diesel injection just as in hybrid drives including brake system and energy management.

Such a wide knowledge base is essential for competently coping with the task of systems integration for hybrid systems.

For this very purpose, Bosch founded the Project Center Hybrid Systems.

At the end of 2004, already more than 60 associates were working in development and sales of hybrid systems, but by the end of 2005 this number is expected to rise to 130.

In comparison to equally powerful vehicles with more conventional combustion engines, hybrid engines produce lower levels of carbon dioxide and other emissions but require more sophisticated technological equipment.

Hybrid technology offers an improvement in fuel economy and carbon dioxide (CO2) emissions and is seen to be especially efficient in dense inner-city traffic.

For a vehicle with a conventional petrol engine of 170kW and an automatic transmission, an average of 20% fuel efficiency or reduction in carbon dioxide can be achieved.

This is possible with a smaller combustion engine with an additional electric motor for boosting, resulting in the same overall maximum performance.

However, when driving on a motorway, a state-of-the-art diesel engine will consume less fuel than a petrol hybrid.

The advantages of the hybrid technology diminish in comparison to a conventional petrol engine with direct injection optimised for fuel savings.

A realistic alternative is the diesel hybrid which, although has a greater initial cost in comparison to a petrol engine, offers a dramatic reduction in overall running costs.

The fuel saving potential of a diesel hybrid compared with a vehicle with only diesel engine amounts to up to 15% in mixed driving modes.

This is based on calculations of simulations conducted with vehicles of the same maximum performance with conventional or hybrid drives, respectively.

Previous market assessments assume a market share of 5% in Japan, 4% in the USA and 2% in Western Europe by 2015.

Estimates by independent market research institutes and some OEMs even assume two or three times higher market shares.

Bosch assumes that some 50 different hybrid models will be on the market worldwide by 2010.

Bosch expects the largest market growth in North America.

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