Intelligent Drives for Eco-Friendly, More Fuel-Efficient Commercial Vehicles

Scaleable hybrid drive systems for commercial vehicles

As one of the world's leading suppliers of hybrid and electric drives, Continental's Powertrain Division is adapting hybrid vehicle technologies to the needs of the commercial vehicle sector as well. Projects in this vein include start-stop functions for automatic red-light switch-off of the engine, mild hybrid drives, which give the combustion engine a noticeable torque boost when accelerating and which recharge the energy storage unit through regenerative brake functions, and full hybrid drives with the option of purely electric driving. In cooperation with its strategic partner, ZF Friedrichshafen AG, Continental Automotive Systems is intensifying the development, production and marketing of hybrid drive systems and components. Continental’s modular concept proves of advantage, moreover, in standardizing versatilely combinable components and in terms of quality. It also cuts back development times.

The module includes the energy storage unit (high-performance battery), the voltage transformer for powering the vehicle power supply, the electric motor and the inverter for different engine-power classes. Scalable hybrid systems with additional electrical outputs of up to 150 kilowatts can be assembled from these components.

Electronic engine control systems for greater fuel efficiency

The latest-generation commercial vehicle engine control units from Continental have been designed to meet the stringent exhaust emission limits slated to take effect in the next few years – EPA 2010 (Environmental Protection Agency, U.S.A.), Japan 09, and Euro 6 standard. They also help enhance commercial vehicle fuel efficiency. Developed for engines with four to eight cylinders with a typical cubic capacity of four to 16 liters, they can regulate every conventional injection and emission control system in medium-duty and heavy-duty engines. For the aftertreatment of exhaust gases, the electronics system controls the timing and quantity of fuel injected, the turbocharger and the exhaust gas recirculation. It meters injection of a precise amount of carbamide additive for SCR (Selective Catalytic Reduction) purification of the exhaust gas. The latter is necessary to further reduce nitrogen oxide emissions.

Piezo technology for clean and efficient diesel engines

Continental’s trend-setting piezo common rail injection system for diesels ensures low fuel consumption – and thus lower emissions – in the case of small vans and American pickups with displacement of 6,5-liters or less. Piezo technology further guarantees uniformly precise metering of both very small and larger quantities of fuel. Rapid switching allows extremely exact adjustment of the injection profile to the engine's operating state at any given moment. Piezo technology offers a three percent consumption advantage over conventional diesel injection engines, thereby making it easier to comply with emissions limits.

To conform to ever more stringent environmental protection stipulations, the Powertrain division has developed a new piezo injector with direct drive and quantity control loop. It gives engine developers the potential to further reduce consumption and emissions. Thanks to the direct drive the nozzle needle gets by without a hydraulic boost. It can be actuated even more rapidly and accurately.

In addition, the injection rate pattern for individual injections can now, for the first time, be flexibly configured. This ideally backs up the multiple-injection systems found in modern common-rail diesel engines. The piezo actuator simultaneously functions as a sensor by feeding the precise position of the nozzle needle back to the engine control unit. In sum effect, this constitutes the first closed quantity control loop. With combustion optimized and injection pressure having been increased to 2000 bar, particulate and nitrogen oxide emissions can be reduced by some 35 percent. The direct drive injector is, therefore, the key technology allowing engine manufacturers to meet the limits specified in the Euro 6 exhaust gas directive set to take effect in 2014. The first series production application of the new technology will be in a light commercial vehicle in 2009.

Sensors and actuators for an optimum combustion process in the engine

Exact interaction of all the components involved in mixture formation, engine management and exhaust gas aftertreatment is possible only if the engine’s operating state can be quickly and accurately sensed and influenced at all times To achieve this, a multitude of sensors and actuators is required. Electronic actuators developed expressly for commercial vehicles specifically optimize the combustion air supply and the exhaust gas recirculation rate to markedly reduce the diesel engine's untreated emissions. In addition, a NOx sensor measures the nitrogen oxide concentration and the air-fuel ratio in the exhaust gas and passes the data obtained on to the engine management system. On this basis parameters for injection and exhaust gas aftertreatment can be quickly and efficiently adjusted. With the NOx sensor it is likewise possible to monitor the proper functioning of exhaust gas aftertreatment and diagnose errors.

By optimizing combustion it is possible to drastically reduce the amount of particulate mass emitted by commercial vehicle diesel engines. With additional exhaust gas purification systems, further significant reductions in particulate emissions – to cite one example – can be achieved. In Emitec Continental has a strong partner in this pursuit. The company makes mounts for state-of-the-art exhaust gas filters and exhaust-gas converters.