Abteilung Fahrzeugtechnik
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Die Schwingungsdämpfer von Pkw werden in Deutschland bei der regelmäßigen technischen Überwachung im Rahmen der Hauptuntersuchung nach Paragraph 29 StVZO überprüft. In eingebautem Zustand werden sie dabei im wesentlichen nur einer Sichtkontrolle unterzogen, bei der die Dichtigkeit der Dämpfer und ihre äußerliche Unversehrtheit beurteilt werden. Ziel der Untersuchung war die Klärung der Frage, ob die Notwendigkeit einer aussagekräftigeren Kontrolle der Schwingungsdämpfer bei der regelmäßigen technischen Überwachung von Kraftfahrzeugen besteht, da die objektive Messung der Dämpferleistung problematisch ist und der Nutzen einer solchen Maßnahme bisher nicht quantifiziert werden kann. Objektive Prüfergebnisse an Schwingungsdämpfern sind jedoch nur in ausgebautem Zustand zu erhalten. Durch die Untersuchung sollte über eine "Ist-Zustands-Prüfung" von im Verkehr befindlichen Pkw und eine darauf aufbauende Hochrechnung der Anteil der Fahrzeuge, die mit defekten Dämpfern fahren, festgestellt werden. Die Auswertung der Reihenuntersuchung ergab, dass von 5.749 untersuchten Pkw 450 Pkw eine Fahrwerksbeurteilung erhielten, nach der an mindestens einem Rad der prüfstandspezifische Grenzwert nicht eingehalten wurde, was in der Regel auf einen defekten Dämpfer zurückzuführen ist. Dies entspricht hochgerechnet einem Anteil von 7,8 Prozent der zugelassenen Pkw. Folgt man den durch die Reihenuntersuchung ermittelten Ergebnissen und den bisher diskutierten Grenzwerten von 50 Prozent für die Restwirkung der Dämpfer, so würde die Einführung einer obligatorischen Dämpferprüfung zu erheblichen Kosten führen, deren Nutzen jedoch aufgrund fehlender Angaben derzeit nicht festgestellt werden kann. In Anbetracht der Unsicherheiten bezüglich des Einflusses defekter Schwingungsdämpfer auf das Unfallgeschehen und der ermittelten Defektrate konnte die Einführung einer obligatorischen Prüfung auf einem Prüfstand im Rahmen der regelmäßigen Hauptuntersuchung nicht abschließend bewertet werden.
In der Europäischen Gemeinschaft werden derzeit jährlich ca. 50.000 Menschen bei Verkehrsunfällen getötet, ca. 10.000 davon als Fußgänger. Von den 10.600 (1992) in der Bundesrepublik Deutschland bei Straßenverkehrsunfällen Getöteten waren 1.800 Fußgänger (etwa 17 Prozent). Problemgruppen bei Fußgängerunfällen bilden die Kinder wegen ihrer hohen Unfallhäufigkeit und alte Personen wegen ihrer hohen Unfallschwere. Kopfverletzungen sind die häufigste Todesursache bei Fußgängerunfällen. Eine Verringerung der Unfallschwere kann - außer durch Verminderung von Fahr- beziehungsweise Aufprallgeschwindigkeiten der Fahrzeuge - nur durch konstruktive Eingriffe an der vorderen Fahrzeugaußenkontur oder dem Unterbau von Pkw erfolgen. Dazu ist es notwendig, einheitliche Prüfverfahren für die Beurteilung der "Fahrzeugaggressivität" gegenüber Fußgängern bereitzustellen. Die Ableitung eines Prüfvorschlages zur Simulation des Kopfaufpralls auf Fronthauben von Pkw beim Fußgängerunfall, unterteilt in Kopfaufpralltests für Erwachsene und Kinder, ist Gegenstand dieser Arbeit. Es werden, ausgehend von einer Analyse der Unfallstatistik, der Entstehungsmechanismus von Kopfverletzungen erklärt, die für ein Prüfverfahren notwendigen Eingangsparameter (Masse, Geschwindigkeit, Aufprallstellen am Fahrzeug etc.) abgeleitet und die Ergebnisse der gewählten Prüfkörpertestmethode mit Ergebnissen von Leichenversuchen verglichen. Eine Kosten-/Nutzen-Betrachtung am Schluss der Arbeit zeigt, dass sich bei nur geringen Kosten ein volkswirtschaftlicher Nutzen durch eine allgemeine Anwendung des Prüfverfahrens mit ca. 270 Millionen DM allein in der Bundesrepublik Deutschland pro Jahr erzielen ließe.
At the 2001 ESV-Conference the EEVC working group on compatibility (WG 15) reported the first phase of the research work to investigate the major factors influencing compatibility between passenger cars. Following this, WG15 performed an interim study, which was partly subventioned by the European Commission, the results of which are reported in this paper. In the next phase of work, it is intended to complete the development of a suite of test procedures and associated performance criteria to assess the compatibility of passenger cars in frontal impacts The main areas of work for the interim study were: - in depth accident data analysis - the development of methods to assess the potential benefit of improved compatibility - crash testing. The accident analysis identified the major compatibility problems to be poor structural interaction, stiffness mismatching and compartment strength. Different methods to assess the potential benefit of improved compatibility were applied to in depth accident data. Full scale crash testing including a car to car test was performed to help develop the following candidate compatibility test procedures: - a full width wall test with a deformable aluminium honeycomb face and a high resolution load cell wall - an offset barrier test with the EEVC barrier face and a high resolution load cell wall - an offset barrier test with the progressively deformable barrier (PDB) face. The results of the interim study will be presented in detail and the proposed methodology of the next phase to complete the development of a suite of test procedures for the assessment of car to car compatibility in frontal impacts will be outlined
When the EEVC proposed the full-scale side impact test procedure, it recommended that consideration should be given to an interior headform test in addition. This was to evaluate areas of contact not assessed by the dummy. EEVC Working Group 13 has been researching the parameters of a possible European headform test procedure in four phases. Earlier stages of the research have been presented at previous ESV conferences. The conclusions from these have suggested that the US free motion headform should be used in any European test procedure and that it should be a free flight test, not guided. This research has now culminated in proposals for a European test procedure. This paper presents the proposed EEVC side impact interior headform test procedure, giving the rationale for the test and the first results from the validation phase of the test protocol.
The development of tyre- and truck-manufacturers leads to the direction to introduce wide base single tyres (size 495/45R22,5) instead of twin tyres on the driving axle of trucks, tractors and busses. To study the driving behaviour and safety of various trucks and units with different tyre combinations and loading conditions was the aim of the study. A computer-aided simulation was used for this investigation. Drive tests with a 40 t unit with prototype single tyres on the drive axle were carried out to verify the simulation. Alterations in driving behaviour and driving safety are mainly dependent on the tyre cornering stiffness. The prototype wide single tyres had a higher lateral stiffness which leads to a higher degree of under-steering (safer driving behaviour). The altered spring base on the drive axle had no influence on the side- tilt stability of vehicle combinations but the solo truck profited from the higher rear axle roll stiffness (less danger for roll-over accidents). As far as the driving safety is concerned nothing speaks against wide base tyres on the drive axle. The simulation of a tyre defect in a bend (assuming 40% of the max. transferable side force for the flat tyre) showed no increased danger using wide single tyres. Later driving tests showed however the need of tyre run flat possibilities to avoid jack-knifing of road trains. Also tyre pressure monitoring systems and electronic stability programs for the trucks are advised.
The frontal crash is still an important contributor to deaths and serious injured resulting from road accidents in Europe. As the Hybrid-III dummy used in crash tests is over two decades old, the European Enhanced Vehicle-safety Committee is studying the potential for a new test device. Key is the availability of a well-defined set of requirements that identifies the minimum level of biofidelity required for an advanced frontal dummy. In this paper, a complete set of frontal impact biofidelity requirements, consisting of references , description of test conditions and corridors, is presented.
The Swedish National Road Administration (SNRA), the Japanese Automobile Research Institute (JARI) and the Federal Highway Research Institute (BASt) are co-operating in the International Harmonized Research Activities on Intelligent Transportation Systems (IHRA-ITS). Under this umbrella a joint study was conducted. The overall objective of this study was to contribute to the definition and validation of a "battery of tools" which enables a prediction and an assessment of changes in driver workload due to the use of in-vehicle information systems (IVIS) while driving. In this sense \"validation\" means to produce empirical evidence from which it can be concluded that these methods reliably discriminate between IVIS which differ in terms of relevant features of the HMI-design. Additionally these methods should also be sensitive to the task demands imposed on the driver by the traffic situation and their interactions with HMI-design. To achieve these goals experimental validation studies (on-road and in the simulator) were performed in Sweden, Germany and Japan. As a common element these studies focused on the secondary task methodology as an approach to the study of driver workload. In a joint German-Swedish on-road study the Peripheral Detection Task (PDT) was assessed with respect to its sensitivity to the complexity of traffic situations and effects of different types of navigation systems. Results show that the PDT performance of both the German and the Swedish subjects reflects the task demands of the traffic situations better than those of the IVIS. However, alternative explanations are possible which will be examined by further analyses. Results of this study are supplemented by the Japanese study where informational demands induced by various traffic situations were analysed by using a simple arithmetic task as a secondary task. Results of this study show that relatively large task demands can be expected even from simple traffic situations.
The European Enhanced Vehicle-safety Committee (EEVC) Working Group 13 for Side Impact Protection has been developing an Interior Headform Test Procedure to complement the full-scale Side Impact Test Procedure for Europe and for the proposed IHRA test procedures. In real world accidents interior head contacts with severe head injuries still occur, which are not always observed in standard side impact tests with dummies. Thus a means is needed to encourage further progress in head protection. At the 2003 ESV-Conference EEVC Working Group 13 reported the results on Interior Headform Testing. Further research has been performed since and the test procedure has been improved. This paper gives an overview of its latest status. The paper presents new aspects which are included in the latest test procedure and the research work leading to these enhancements. One topic of improvement is the definition of the Free Motion Headform (FMH) impactor alignment procedure to provide guidelines to minimize excessive headform chin contact and to minimize potential variability. Research activities have also been carried out on the definition of reasonable approach head angles to avoid unrealistic test conditions. Further considerations have been given to the evaluation of head airbags, their potential benefits and a means of ensuring protection for occupants regardless of seating position and sitting height. The paper presents the research activities that have been made since the last ESV Conference in 2003 and the final proposal of the EEVC Headform Test Procedure.
The European Enhanced Vehicle-safety Committee wants to promote the use of more biofidelic child dummies and biomechanical based tolerance limits in regulatory and consumer testing. This study has investigated the feasibility and potential impact of Q-dummies and new injury criteria for child restraint system assessment in frontal impact. European accident statistics have been reviewed for all ECE-R44 CRS groups. For frontal impact, injury measures are recommended for the head, neck, chest and abdomen. Priority of body segment protection depends on the ECE-R44 group. The Q-dummy family is able to reflect these injuries, because of its biofidelity performance and measurement capabilities for these body segments. Currently, the Q0, Q1, Q1.5, Q3 and Q6 are available representing children of 0, 1, 1.5, 3 and 6 years old. These Q-dummies cover almost all dummy weight groups as defined in ECE-R44. Q10, representing a 10 year-old child, is under development. New child dummy injury criteria are under discussion in EEVC WG12. Therefore, the ECE-R44 criteria are assessed by comparing the existing P-dummies and new Q-dummies in ECE-R44 frontal impact sled tests. In total 300 tests covering 30 CRSs of almost all existing child seat categories are performed by 11 European organizations. From this benchmark study, it is concluded that the performance of the Q-dummy family is good with respect to repeatability of the measurement signals and the durability of the dummies. Applying ECE-R44 criteria, the first impression is that results for P- and Q-dummy are similar. For child seat evaluation the potential merits of the Q-dummy family lie in the extra measurement possibilities of these dummies and in the more biofidelic response.