Bosch Sees Increasing Hybridization

Bernd Bohr, then-chairman of the Bosch Automotive Group (bosch.com), made some interesting observations at a technical event in mid-June (he retired from his position at the end of June 2013) that indicate the auto industry is on a path toward increased electrification, whether this means hybrids or electric vehicles (Bosch is behind the electric drive system in the Fiat 500e).

Bohr pointed out that globally, most cars run on gasoline or diesel and are likely to through the end of the decade. He went on to say, “However, slowly but surely, the number of alternatives is growing. Looking ahead to 2020, we expect to see 110 million newly registered vehicles around the world by then, 12 million of them with an electrical powertrain. This latter figure will grow gradually throughout the decade, with its growth curve becoming ever steeper in the next.”

Bohr said that Bosch plans to contribute to the growth of electric vehicles by developing lithium-ion batteries that will provide double the range at half the cost per kilowatt hour.

Looking toward the 2020 regulations in Europe that call for average CO₂ emissions of 95 grams/kilometer, Bohr suggested that while the diesel and gasoline engines in the subcompact class should meet the regulation without electrification, when it comes to compact, hybridization is needed, as well as other improvements to reduce fuel consumption.

Bosch is working on a wide range of technologies to address this, including what it calls the “eClutch” for manual trans-missions. This unit automatically shifts into neutral when the vehicle is not under acceleration, thereby reducing the amount of fuel used by as much as 5%.

Of course, the number of manual transmissions (particular in the U.S.) is decreasing, so they’re working on other technologies, like a start-stop system that is integrated with the navigation system: depending on factors like the terrain, the driver can be coached to lift from the accelerator when it isn’t necessary, which, Bohr said, “can result in fuel savings of up to 15% in real driving conditions” on highways.

There is a “boost regeneration system” (BRS) for use on midsized cars. This is a hybrid system that uses a 48-volt electrical system. When the vehicle brakes, energy is sent to a 0.25-kWh lithium-ion battery, where it is stored until required by acceleration. The system also works as a start-stop system, but has the capability to shut off the engine when the car is coasting (and the driver is not deploying either the accelerator or brake pedals). The BRS system is capable of reducing CO₂ emissions by up to 15%.

And in a slight twist to conventional hybrid systems, Bosch is working with PSA Peugeot Citroën on a hydraulic hybrid system. Here, there is a nitrogen pressure accumulator and a hydraulic fluid reservoir. When braking, the kinetic energy acts on the fluid, which compresses the gas to over 300 bar. Then, when needed for accelerator, the gas is allowed to expand, thereby putting a compressive force on the hydraulic fluid, which drives a hydraulic motor that is connected to the transmission. While this setup is more limited in capacity and range than lithium-ion battery-based hybrids, it is said to be more economical and capable of reducing fuel consumption by up to 30%.

Robert Bosch Corp.