Search Results

The reduction of CO₂ emissions represents a major goal of governments worldwide. In developed countries, approximately 20% of the CO₂ emissions originate from transport, one third of this from commercial vehicles. CO₂ emission legislation is in place for passenger cars in a number of major markets. For commercial vehicles such legislation was also already partly published or is under discussion. Furthermore the commercial vehicles market is very cost sensitive. Thus the major share of fuel cost in the total cost of ownership of commercial vehicles was already in the past a major driver for the development of efficient drivetrain solutions. These aspects make the use of new powertrain technologies, specifically hybridization, mandatory for future commercial powertrains. While some technologies offer a greater potential for CO₂ reduction than others, they might not represent the overall optimum with regard to the total cost of ownership.

This paper analyses the potential of dual clutch transmissions for MD and HD commercial vehicles in India. It compares vehicle performance, i.e. duration of a given transport cycle, and fuel consumption during this transport cycle for a 49 to. long haulage truck under typically given driving conditions in India. Additionally a performance comparison between 6 speed and 8 speed transmissions on long haul trucks in India is shown. The performance of different transmission types (MT, AMT and DCT) as well as 6 respectively 8 speed transmissions for each transmissions type are compared and discussed. The fuel efficiency as well as the cycle time of each individual transmission have been analyzed by powertrain system simulations. Furthermore the design of a modular transmission family concept for commercial vehicles (truck & bus) is presented. It combines both, a manual transmission as well as a powershift capable double clutch transmission within the same transmission family.

Best fuel efficiency is one of the core requirements for commercial vehicles in India. Consequently it is a central challenge for commercial vehicle OEMs to optimize the entire powertrain, hence match engine, transmission and rear axle specifications best to the defined application. The very specific real world driving conditions in India (e.g. traffic situations, road conditions, driver behavior, etc.) and the large number of possible commercial powertrain combinations request an efficient and effective development methodology. This paper presents a methodology and tool chain to specify and develop commercial powertrains in a most efficient and effective way. The methodology is based on the measurement of real world driving scenarios, identification of representative Real World Driving Profiles and vehicle system simulation which allows extended analysis of the road topography, the traffic situation as well as the driver behavior.