Abstract
Humankind is challenged to reduce carbon dioxide emissions and preserve the remaining fossil fuels for other applications than energy, where possible substitutes are hardly in sight (e.g.: chemicals, pharmaceutics). This demanding task is strongly linked to individual transportation, which contributes to the consumption of fossil fuels to a large extent. Therefore automotive industry faces a demanding task to increase fuel economy of passenger cars while increasing safety, comfort and functionality. In addition vehicle concepts are driven by marketing strategies and the end consumers’ various individual needs and desires.
The present study aims at evaluating the reasonability of the drive train and engine performance of the passenger cars that have been available in Europe in 2010. The technical characteristics of the existing passenger cars are collected in a database. The model range covers all passenger car vehicle types from micro cars to vans and sports utility vehicle. Based on a longitudinal dynamics approach the driving resistance of each vehicle is calculated for the most demanding driving situations in town, on the country road and on the motorway. These most demanding driving situations include the vehicle being loaded to gross vehicle weight, driving at maximum allowed speed, on a road with maximum realistic inclination with a certain amount of acceleration reserve. As the next step the required engine power and torque to overcome the total driving resistance is determined using the technical specifications of the existing cars. Finally the calculated required engine torque and engine power is compared to the engine characteristics of the respective existing passenger car.
This comparison of the existing car concepts to the ‘reasonable’ concepts based on condition to comply with the transportation task shows, that most cars on the market have significant excessive power. The study illustrates the expected trends of increasing excessive power from small cars to large cars such as SUVs. In addition the study reveals special challenges, inherent to the system, when developing micro car concepts with the restriction of multiple applications of drive train packages in different vehicle concepts.
Overall the study indicates that the present key factors for the development of passenger car concepts are not strictly reasonable from an environmental and vehicle dynamics point of view. The results shall be seen as a supportive study for automotive engineering to cope with the steady challenge to develop reasonable and environmentally friendly car concepts for future markets under the aspect of drastic reduction of energy consumption.
Keywords: drivetrain, engine performance, reasonability, passenger car concepts, model range 2010.