Search Results

The increasing demand of four-wheel drive vehicles is pushing the market for more optimized transfer cases. In modern cars the transfer case is usually controlled electronically because this provides more design freedom and the possibility of diagnostics feedback and direct control by the powertrain ECU. A typical transfer case control would include different sensors for angle-rotational speed and position sensing, a keypad for the mode selection by the driver, a microcontroller to compute the information and some high current drive circuitry for driving the actuators. But, while SUV's are known to provide ample space for the passengers, the electronics cannot claim that luxury. With every function added the available board space per function is getting smaller and the additional power dissipation is of concern. This is especially true for high current components like the transfer case motor driver.

Function analysis provides the backbone of systems engineering design and underpins the use of Design for Six Sigma and Failure Mode Avoidance tools. Identification and management of interfaces is a key task in systems engineering design, in ensuring that the system achieves its functions in a robust and reliable way. The aim of the work presented in this paper was to develop and implement a structured approach for function analysis of a complex system, which focuses on the identification and characterization of interfaces. The proposed approach is based on the principle of separation of the functional and physical domains and development of function decomposition through iteration between functional and physical domains. This is achieved by integrating some existing / known engineering tools such as Boundary Diagram, State Flow Diagram, Function Tree and an enhanced interface analysis within a coherent flow of information.

Dynamic simulation is routinely used to analyze the occupant response to motor vehicle impact. That said, while commercially-available models have been subjected to numerous high-severity level validation studies, little attention has been given to lower severity crashes. While high severity crashes typically result in more severe injury, the vast numbers of lower severity “fender bender” type crashes and the ensuing high medical costs warrant study related to biomechanics and vehicle design. The scope of this study is directed at addressing the validity of these models for analyzing occupant response to collinear rear impact involving delta-V less than 5 mph. As part of this study, a series of five vehicle-to-vehicle collisions with instrumented volunteer occupants were performed with closing speeds of 1.1, 1.9, 2.9, 4.0 and 5.1 mph. These impacts produced delta-V, for the target vehicle, of 0.6, 1.8, 2.5, 3.1 and 3.2 mph, respectively.

Event Data Recorder (EDR) technology has been incorporated into the Electronic Control Modules (ECMs) of many on-highway heavy trucks. One benefit of this technology is its applicability to vehicle collision investigation and reconstruction ( Goebelbecker & Ferrone, 2000 ; van Nooten & Hrycay, 2005 ). However, collisions that cause extensive damage to the truck may cause a loss of electrical power to the ECM, which might interrupt the data storage process. This research is an attempt to determine the effects of power loss on heavy vehicle ECMs 1 , and the associated effects on data collected by the EDR function. Controlled testing was conducted with Detroit Diesel, Mercedes, Mack, Cummins, and Caterpillar engines, and power failures were created by artificially interrupting power between the vehicle's battery and ECM at predetermined intervals. EDR data from the test vehicles were extracted after each test, and the presence or absence of new data was examined.

This paper validates the single-track vehicle driver model available in PC-Crash simulation software. The model is tested, and its limitations are described. The introduction of this model eliminated prior limitations that PC-Crash had for simulating motorcycle motion. Within PC-Crash, a user-defined path can be established for a motorcycle, and the software will generate motion consistent with the user-defined path (within the limits of friction and stability) and calculate the motorcycle lean (roll) generated by following that path at the prescribed speed, braking, or acceleration levels. In this study, the model was first examined for a simple scenario in which a motorcycle traversed a pre-defined curve at several speeds. This resulted in the conclusion that the single-track driver model in PC-Crash yielded motorcycle lean angles consistent with the standard, simple lean angle formula widely available in the literature.

The challenges concerning noise, vibration, and harshness (NVH) performance in the vehicle cabin have been significantly changed by the powertrain shift from a conventional drive unit with an internal-combustion engine (ICE) to electric drive units (eAxles). However, there is few research regarding the impact of electrification on NVH considering the influence of the context such as multi-stimuli and traffic rules during a real-life driving. In this study, the authors conducted test drives using EVs and ICEVs on public roads in Europe and conducted a statistical analysis of the difference in driver impression of NVH performance based on interviews during actual driving. The impression data were categorized into clusters corresponding to related phenomena or features based on driver comments. Furthermore, the vehicles data (vehicle speed, acceleration, GPS information, etc.) were recorded to associate the driver impressions with the vehicle’s conditions when the comments were made.

The objectives of this study were to provide insights on how injury risk is influenced by occupant demographics such as sex, age, and size; and to quantify differences within the context of commonly-occurring real-world crashes. The analyses were confined to either single-event collisions or collisions that were judged to be well-defined based on the absence of any significant secondary impacts. These analyses, including both logistic regression and descriptive statistics, were conducted using the Crash Investigation Sampling System for calendar years 2017 to 2021. In the case of occupant sex, the findings agree with those of many recent investigations that have attempted to quantify the circumstances in which females show elevated rates of injury relative to their male counterparts given the same level bodily insult. This study, like others, provides evidence of certain female-specific injuries.

Seatback and head restraints are the primary restraining devices in rear-impact collisions. The seatback failures expose front seat occupants to dive deep into the rear compartment survival space. Furthermore, it allows the occupants to get in a position with lower spinal tolerance to the impact direction. This paper employs sled tests to demonstrate the dangers of seatback failures in severe rear impact by allowing the occupants to orient their spine in its lowest tolerance zone to the impact direction. Furthermore, the sled test shows the potential of head pocketing phenomena and torso augmentation producing compressive cervical spine loading enough to cause first-order neck buckling. Finally, the results of collapsing seatback dynamics are compared to the strong seatback performance by conducting a similar test with a strong ABTS seatback.

Reducing criteria pollutants while reducing greenhouse gases is an active area of research for commercial on-road vehicles as well as for off-road machines. The heavy duty on-road sector has moved to reducing NOx by 82.5% compared to 2010 regulations while increasing the engine useful life from 435,000 to 650,000 miles by 2027 in the United States (US). An additional certification cycle, the Low Load Cycle (LLC), has been added focusing on part load operation having tight NOx emissions levels. In addition to NOx, the total CO2 emissions from the vehicle will also be reduced for various model years. The off-road market is following with a 90% NOx reduction target compared to Tier 4 Final for 130-560 kW engines along with greenhouse gas targets that are still being established. The off-road market will also need to certify with a Low Load Application Cycle (LLAC), a version of which was proposed for evaluation in 2021.