|In the long run, the large variety of drivetrain concepts will give way to electric drive. Source: Bosch. Click to enlarge.|
While full electric powertrains (battery and fuel cell) will at some point become pervasive in light-duty vehicles, the dominance of the internal-combustion engine will remain unchallenged over the next twenty years, according to Robert Bosch GmbH executives at their annual International Automotive Press Briefing in Boxberg, Germany. This is due in part to important technological challenges to powertrain electrification that must first be overcome and in part to ongoing efficiency improvements in combustion engine technology.
As a supplier, Bosch is active in both areas, said Dr. Bernd Bohr, chairman of the Bosch Automotive Group. Bosch is working hard to get the electric drive of the future readied for large-scale series production, while also doing its utmost to further improve the internal-combustion engine for decades to come, Bohr said. The company is investing €3 billion (US$ 4.25 billion) in R&D in the automotive technology sector in 2009.
We will do the one thing without neglecting the other. Our engineers are working to reduce the fuel consumption of gasoline and diesel engines by up to one third. This will make it possible to reduce the carbon dioxide emissions of diesel cars to under 99 grams per kilometer.
...The electric car will come, but in small numbers at first. It will occupy a niche and will not make a noticeable mark on the roads until after 2020. By 2015, we expect to see a sales volume of some 500,000 electric vehicles worldwide. To achieve higher volumes, we must first improve the performance of these vehicles considerably.—Dr. Bernd Bohr
|Comparison of drive concepts for diesel engines, with reductions in fuel consumption. Source: Bosch. Click to enlarge.|
Combustion engines. By 2015, said Dr. Rolf Leonhard, Executive Vice President Engineering, Diesel Systems, the market will see three-cylinder, 1.1- or 1.2-liter engines, both gasoline and diesel, that offer the same 100 kW (134 hp) power and performance of a standard 2.0-liter, four-cylinder engine of today but with much greater fuel efficiency.
The new engines will also be equipped with several additional technologies to increase the overall efficiency of the drivetrain:
- A start-stop system that automatically starts and stops the engine when the car is not in motion, for instance at a red light or in a traffic jam;
- A thermal management system that quickly gets the engine up to optimum operating temperature, and keeps it there;
- A highly efficient generator with a control unit that uses additional braking energy to charge the battery; and
- Many other support functions which, thanks to electrification, work more efficiently and can be better controlled.
|“Hybrid drives and electric cars are playing an increasingly important role...However, CO2 emissions and fuel consumption can be reduced much more quickly and cost-effectively by exploiting the development potential of gasoline and diesel engines.”|
—Dr. Rolf Leonhard
By 2015, said Leonhard, a gasoline-driven car will consume only 5.5 liters per 100 kilometers (43 mpg US)—29% less than a standard engine in 2009. A diesel-powered car in 2015 will only burn 3.6 L/100km (65 mpg US)—a third less than diesel in 2009.
Hybridization can reduce the consumption of gasoline engines by 39%, and of diesel engines by as much as 40%, he said. In addition, automobile manufacturers are using other technologies to further decrease consumption and emissions. By designing more streamlined car bodies, they are reducing aerodynamic drag, and they are also reducing vehicle weight and rolling resistance.
All in all, an automobile which is fully optimized in these ways will consume 50 percent less fuel than today—fuel consumption under standard conditions of around 3.8 liters of gasoline per 100 kilometers [62 mpg US], or 2.6 liters of diesel [90 mpg US], can be achieved. Of course, all this extra technology comes at a cost. But the money that drivers save on fuel means that it pays off in the long run.—Rolf Leonhard
|“The electric motor is the most efficient means of powering a car.”|
Powertrain electrification.On the path toward powertrain electrification, Bosch’s current development activities focus on the hybrid engine, on purely electric driving, and on the range extender, said Wolf-Henning Scheider, President, Gasoline Systems.
In addition to its work on electric motors and drives, Scheider said, Bosch is focusing on the power electronics as a core competency.
Bosch’s first-generation power electronics systems has an installation volume of 13 to 14 liters for 50 kilowatts of electrical power. For the next generation, this will be reduced to five liters, and Bosch is already working on a subsequent three-liter version.
Bosch is also developing a new ESP®system that electronically coordinates the electric motor’s braking power with that of the friction brakes for better regenerative braking. Other activities include development of electric auxiliary systems, as well as charging systems for plug-ins.
What will the electric car look like in 2015? It will weigh around 1,000 kilograms. It will have a drag coefficient of 0.34, and its 40-kilowatt motor will be capable of speeds up to 120 kilometers per hour. In Germany today, the average distance covered each day by 90 percent of cars is under 80 kilometers. According to recent surveys, however, drivers want the electric car to have a minimum range of 200 kilometers. To make this possible, our electric car needs a battery with a capacity of 35-kilowatt hours.
Based on the technology we expect to be available in 2015, this battery will weigh 250 kilograms and cost around 12,000 euros, or 350 euros per kilowatt hour [US$495/kWh]. Depending on the design of the electric vehicle—how heavy it is, for example—and depending on how the lithium-ion battery develops, the cost of the battery may be slightly lower, at around 8,000 euros.—Wolf-Henning Scheider
|SB LiMotive is targeting improvements in power and energy. Source: Bosch. Click to enlarge.|
Li-ion batteries. In 2008, Bosch and Samsung SDI Co. Ltd. established a joint venture to develop, manufacture, and sell lithium-ion batteries for automotive applications. The joint venture—SB LiMotive Co. Ltd.—is based in Korea, and will start production in 2010. (Earlier post.)
In order to bring the lithium-ion battery up to speed for the automobile, we have set the following goals for our development activities at SB LiMotive has set four primary goals for its work in automotive Li-ion technology, said Dr. Joachim Fetzer, Executive Vice President, SB LiMotive:
- To considerably improve the power and energy density of the lithium-ion battery
- To significantly reduce battery costs
- To further improve cycle durability and service life
- To adapt the battery to the safety standards of the automotive industry
To achieve these goals, SB LiMotive is taking a three-pronged development approach:
- In the chemical components of the individual battery cell and its structure
- In the integration of the cells to form battery modules
- In the battery management system which serves to monitor and regulate the individual cells
Li-ion cells for hybrid applications today deliver about 3,000 W/kg of specific power and some 85 Wh/kg of specific energy, Fetzer said. In contrast, those for electric cars deliver 110 Wh/kg. To improve both energy and power density, SB LiMotive is focused on optimizing the cell chemistry, with goals of a power density of more than 4,000 W/kg by 2012 for hybrid applications and an energy density greater than 150 Wh/kg for electric car applications—a 30-40% improvement in the key performance indicators of lithium-ion batteries within 3 years.
We would be able to reduce the number of cells [required in vehicle packs] in the future if we could considerably increase the specific power or specific energy of the materials in each cell. This would make the battery lighter and, most importantly, less expensive. Costs can also be reduced by producing on a larger scale. Plus, the battery will become more affordable with a larger procurement volume of raw materials and an increasing standardization of components. As our experience grows over the next few years, we will certainly find new ways to gradually optimize the process costs of battery cell manufacturing. This includes the cheaper production of chemical raw materials as well as the integration of cells in battery modules in large-scale series production. The general consensus is that we will be able to produce a battery pack for about 350 euros per kilowatt hour by 2015, or about two-thirds of the current cost.—Dr. Joachim Fetzer