DETROIT - Automakers are beginning to grapple with technology changes needed for 42-volt systems, but Denso Corp. views the voltage as only a resting point in the scramble to meet global environmental requirements.
By 2010, higher-voltage cars will be entering the market in large numbers, said Kazuo Matsumoto, managing director and member of the board of Denso Corp. in Japan.
But the reason for higher voltage has less to do with consumer demands than global environmental regulations. Matsumoto called it a 'continuous progression to better systems.'
These cars will resemble hybrids such as the Toyota Prius and Honda Insight, more than they will conventional cars converted to so-called mild hybrids using a 42-volt starting system. Denso already supplies components to Honda for its hybrid vehicle.
Matsumoto said that for vehicles using the car body as a common ground, 42 volts is the safe upper limit; that's why the industry is harmonizing on that higher voltage for its intermediate step. But Matsumoto and other Denso executives said 42-volt technology alone won't achieve emission reductions mandated as part of global warming initiatives.
Need for 42-plus
To reach those emissions reductions, vehicles must move to what Denso executives called 42-plus levels - systems that can provide up to 16 kilowatts of energy per car rather than the 8 kilowatts expected from early 42-volt technology.
'When we think about all other electrical systems, we see much getting common around 2010,' Matsumoto said.
That year marks the legislative deadline in Japan for a 15 percent reduction in carbon dioxide emissions. A more demanding European deadline that requires a 25 percent industrywide reduction of carbon dioxide comes in 2008.
'We see the drive for higher voltage is related to emissions. You can see in Europe, they are concentrated on reduction of carbon dioxide. On the contrary, in the United States, they are concentrating on emissions. Probably, in the case of Japan, they are concentrated on both. So the drivers are a little bit different, region by region,' Matsumoto said
Even the shift to the most basic 42-volt systems is more likely to be driven by regulations than by consumer demand, said Douglas Patton, vice president of Denso International America Inc., of Farmington Hills, Mich. Denso has calculated that, of existing vehicle fleets, re-equipping them by introducing lean-burn engines, continuously variable transmissions and weight reduction will not meet the European standard.
'The customer is probably not the driver for the shift to 42 volts,' he said. 'Going to 42 volts is going to be somewhat transparent to the owner.'
That's because the earliest applications of 42-volt technology are expected to influence engine emissions and fuel economy, rather than power-hungry features for automobile interiors.
Denso and other suppliers face an interesting balancing act as the voltages emerge, Patton said. The suppliers need to balance demand from their automaker customers for interim 42-volt systems with demand for the isolated, higher-voltage systems of true hybrid vehicles. At the same time, they need to continue making advances in the technology that drives conventional 14-volt systems.
Overall, Patton said, the major change is that electricity in the car will now become a highly managed, computer-controlled system. As an example, Denso introduced an efficient AC/DC converter to reduce 42-volt generated power to the 14 volts needed for chassis electronics. The converter is 95 percent efficient. And though that's high efficiency for such a converter, it's still wasting 5 percent of the electricity that goes through it.
'We have to make up that 5 percent from another part - the wiring, for example,' said Chad Kosuge, vice president of Denso International America.