· With innovative technology, fuel consumption and CO2 emissions of diesel and gasoline engines to be reduced by some 30 percent by 2015

Thanks to Bosch technology, the internal-combustion engine will become even more economical and eco-friendly in the years to come. This means that in the future, gasoline and diesel engines will consume less fuel and emit less CO2, and will thus be able to meet stricter emissions standards. As a leading automotive supplier Bosch still sees the internal-combustion engine as the technology of choice for the next 20 years. At the same time, however, the company has also stepped up its activities toward powertrain electrification.

A new generation of direct injection for gasoline and diesel engines – to be used in combination with downsizing concepts and turbocharging – will play a significant role in making cars more fuel-efficient. When engines are downsized, engine displacement is reduced, often combined with a reduction in the number of cylinders. These smaller engines are characterized by reduced throttling and friction losses and therefore greater fuel efficiency and lower CO2 emissions. Thanks to turbocharging in combination with direct injection technologies, there is no loss in performance. Assuming downsizing concepts and other technologies are consistently applied, a mid-class vehicle will consume 30 percent less fuel by 2015 than it does today. Bosch is developing systems and components to achieve this aim with both gasoline and diesel engines.

Gasoline engines: Direct injection, turbocharging, and downsizing
Today, the gasoline engine is the most widespread drive technology in the world. Making gasoline engines more efficient can thus lead to significantly lower CO2 emissions. Today, just under two-thirds of cars with gasoline engines sold worldwide are still equipped with a port-fuel injection system. Just by switching to gasoline direct injection in combination with turbo-charging, fuel savings of some 15 percent can be achieved.

Bosch has put together technology packages based on gasoline direct injection in combination with turbocharging. These packages make different levels of downsizing possible. The first of these packages is supplemented by the variable control of intake and exhaust valves as well as by scavenging. Especially at low engine speeds, the process of valve overlap ensures that more fresh air is fed into the cylinders, which considerably boosts torque. This first package further reduces consumption with a start-stop system and a thermal management system to improve the efficiency of the engine. Moreover, an optimized alternator enables braking energy to be recovered as well as electric auxiliary systems to be run solely according to their energy needs.

Wolf-Henning Scheider, president of the Bosch Gasoline Systems division, says: “This can reduce fuel consumption and thus also CO2 emissions by some 22 percent – for a turbocharged 1.4-liter four-cylinder engine with the same power output of around 100 kilowatts as one of today's 2.0-liter standard port-fuel injection engines. The fuel consumption of a mid-class vehicle is then 6.0 liters per 100 kilometers, which corresponds to CO2 emissions of 142 grams per kilometer.”

Even higher charge pressure
With the second technology package for gasoline engines, fuel consumption can be reduced by a full 29 percent by 2015. This scenario foresees an engine with only three cylinders and a displacement of only 1.1 liters. However, power output and torque remain unchanged at 100 kilowatts and some 200 newton meters respectively. Compared with the first package, additional technological features include the turbo-charger's boost pressure, which increases from 1.8 to 2.4 bar. The package also includes more elaborate valve control, which allows not only the valve timing, but also the valve lift itself and thus also the intake diameter, to be varied. Here, fuel consumption amounts to 5.5 liters per 100 kilometers and CO2 emissions to 130 grams per kilometer.

Diesel engines: Increasing injection and charge pressure
Fuel efficiency can be increased even further with the diesel engine. Compared with today's standard 2.0-liter diesel engine, which is equipped with common-rail injection and turbocharging and achieving a power output of 100 kilowatts, by 2015 a mid-class car will consume one-third less fuel, or only 3.6 liters per 100 kilometers, and will emit only 97 grams of CO2 per kilometer.

Dr. Rolf Leonhard, executive vice president engineering at Bosch Diesel Systems, summarizes the main features of the first technology package for the diesel engine: “By increasing exhaust-gas recirculation, charge-air pressure for combustion air, and injection pressure over the greater part of the engine map, we can reduce nitric oxide levels in the combustion process.” In addition, the package contains the same elements already applied in the gasoline engine: smaller engine size reduced in displacement from 2.0 to 1.6-liters, a start-stop system, and thermal management. This cuts fuel consumption by 22 percent, to 4.2 liters per 100 km, and CO2 emissions to 112 grams per kilometer.

Denoxtronic makes engines even more efficient
In a second step, exhaust gas treatment to reduce nitric oxide emissions plays a major role. This is important, since with the transition from Euro 5 to Euro 6 emission standards, nitric oxide (NOx) emissions must be reduced by more than half. At the very least, to reduce nitric oxide emissions, the high-performing diesel engines of heavy vehicles will require a catalytic converter in the future. To this end, Bosch already provides proven Denoxtronic technology for selective catalytic reduction in commercial vehicles.

Denoxtronic also offers opportunities for further reducing fuel consumption. Higher combustion temperatures made possible by the subsequent reduction of nitric oxide improve the diesel engine's efficiency by a further five to seven percentage points. This means that compared with today's standard engine, the fuel consumption of a 1.6-liter four-cylinder engine can be reduced by 28 percent to 3.9 liters per 100 kilometers, which corresponds to 105 grams of CO2 per kilometer. If the engine size is further reduced from four to three cylinders with 1.2 liters of engine displacement and the same power output of 100 kilowatts, fuel consumption can be reduced to 3.6 liters per kilometer (97 grams CO2 per kilometer). This is 33 percent lower than the fuel consumption of today's standard diesel engine.

The Bosch Group is a leading global supplier of technology and services. In the areas of automotive and industrial technology, consumer goods, and building technology, some 275,000 associates generated sales of 38.2 billion euros in fiscal 2009. The Bosch Group comprises Robert Bosch GmbH and its more than 300 subsidiaries and regional companies in over 60 countries. If its sales and service partners are included, then Bosch is represented in roughly 150 countries. This worldwide development, manufacturing, and sales network is the foundation for growth. Each year, Bosch spends more than 3.5 billion euros for research and development, and applies for some 3,800 patents worldwide. With all its products and services, Bosch enhances the quality of life by providing solutions which are both innovative and beneficial. The company was set up in Stuttgart in 1886 by Robert Bosch (1861-1942) as “Workshop for Precision Mechanics and Electrical Engineering.” The special ownership structure of Robert Bosch GmbH guarantees the entrepreneurial freedom of the Bosch Group, making it possible for the company to plan over the long term and to undertake significant up-front investments in the safeguarding of its future. Ninety-two percent of the share capital of Robert Bosch GmbH is held by Robert Bosch Stiftung GmbH, a charitable foundation. The majority of voting rights are held by Robert Bosch Industrietreuhand KG, an industrial trust. The entrepreneurial ownership functions are carried out by the trust. The remaining shares are held by the Bosch family and by Robert Bosch GmbH. Additional information can be accessed at www.bosch.com.

PI6751 - September 2009