Search Results

Lean operating natural gas heavy duty applications have advantages in terms of lower CO2 and PM compared to Diesel applications. This makes operating heavy duty applications on natural gas attractive and currently, they do not have to implement an exhaust particulate filter. However, the challenge is controlling methane emissions over a range of vehicle operating conditions. Methane is extremely stable and light off occurs at temperatures above 400 °C, with high efficiency occurring >500 °C and requires high precious metal loaded catalysts in the range of 150 - 200 g/ft3. Under stoichiometric conditions, 500 °C can be met in many engine operating points however, for lean operating applications, the exhaust temperature can be significantly lower than 500 °C posing a significant challenge for exhaust catalytic CH4 control. This paper will discuss synthetic gas reactor study results using ozone in the feed gas to perform low temperature methane control.

Conventional car manufacturing is extremely capital and energy-intensive. Due to these limitations, major auto manufacturers produce very similar, if not virtually identical, vehicles at very large volumes. This limits potential customization for different users and acts as a barrier to entry for new companies or production techniques. Better understanding of the barriers for low volume production and possible solutions with innovative production techniques is crucial for making low volume vehicles viable and accelerating the adoption of new production techniques and lightweight materials into the competitive marketplace. Additive manufacturing can enable innovative design with minimal capital investment in tooling and hence should be ideal for low and perhaps high volume parts. For this reason, it was desired to evaluate potential opportunities in manufacturing automotive parts with additive techniques.

OEMs are investigating opportunities to reduce vehicle mass, driven by a need to meet upcoming CAFE targets, increase the range and reduce battery size of EVs. A number of lightweight materials including high strength steels, aluminum alloys, plastics and composites are now in production. To facilitate development of corporate R&D and commercialization plans for new materials, it is beneficial to understand the current manufacturing costs for production components, and their impact on piece price at different volumes. This paper investigates design and cost impact of light-weighting with respect to front door and floor assembly of Toyota Corolla and BMW i3. Toyota Corolla has a traditional steel body and is sold in high volumes while BMW i3 has relatively low annual sales and is primarily made of composite, aluminum and plastic parts.

Intake and exhaust system development is an important step in automotive design. The intake system must allow sufficient air to flow into the engine, and the exhaust system must allow exhaust gases to depart at the rear of the vehicle, without excessive pressure loss. These systems must also attenuate the acoustic pressure pulsations generated by the engine, such that the noise emitted from the intake and exhaust orifices is constrained within reasonable limits, and exhibits a sound quality in keeping with the brand and vehicle image. Pressure loss and orifice noise tend to be in conflict, so an appropriate trade-off must be sought. Simulation of both parameters allows intake and exhaust systems to be designed effectively, quickly, cheaply and promptly. Linear simulation approaches have been widely used for intake and exhaust acoustic prediction for many decades.

Future fuel economy targets represent a significant challenge to the automotive industry. While a range of technologies are in research and development to address this challenge, they all bring additional cost and complexity to future products. The most cost effective solutions are likely to be combinations of technologies that in isolation might have limited advantages but in a systems approach can offer complementary benefits. This presentation describes work carried out at Ricardo to explore Intelligent Electrification and the use of Stratified Charge Lean Combustion in a spark ignition engine. This includes a next generation Spray Guided Direct Injection SI engine combustion system operating robustly with highly stratified dilute mixtures and capable of close to 40% thermal efficiency with very low engine-out NOx emissions.

The U.S. Environmental Protection Agency, U.S. Department of Transportation's National Highway and Traffic Safety Administration, and the California Air Resources Board have recently released proposed new regulations for greenhouse gas emissions and fuel economy for light-duty vehicles and trucks in model years 2017-2025. These proposed regulations intend to significantly reduce greenhouse gas emissions and increase fleet fuel economy from current levels. At the fleet level, these rules the proposed regulations represent a 50% reduction in greenhouse gas emissions by new vehicles in 2025 compared to current fleet levels. At the same time, global growth, especially in developing economies, should continue to drive demand for crude oil and may lead to further fuel price increases. Both of these trends will therefore require light duty vehicles (LDV) to significantly improve their greenhouse gas emissions over the next 5-15 years to meet regulatory requirements and customer demand.

Acoustics of automotive intake and exhaust systems have been modelled very successfully for many years using 1D gas dynamic simulations. These use pseudo 3D models to allow complex components to be constructed from simple building blocks. In recent years, tools have appeared that automate the construction of network models from 3D geometries of intake and exhaust components. Using these tools, concurrent noise and performance predictions are a core part of most engine development programmes. However, there is still much interest in the more traditional field of linear acoustics: analysing the acoustic behaviour of isolated components or predicting radiated noise using a linear source. Existing approaches break the intake and exhaust system down into a set of components, each with known acoustic properties. They are then connected together to create a network that replicates the donor non-linear model.

In response to environmental and fossil fuel usage concerns, the automotive industry will gradually move from Hybrid Electric Vehicles (HEV) which includes a shift of internal combustion engines toward Zero Emissions Vehicles (ZEV). Refinement is an important aspect in the successful adoption of any new technology and ZEV brings its own NVH challenges owing to the unique dynamic characteristics of the powertrain and driveline system. This paper presents considerations for addressing dynamic driveline NVH issues that are common to 100% electric vehicles; issues that manifest themselves as groans, rattles and clunks. A dynamic torsional analytical model of the powertrain & driveline will be presented. The analytical model served as the baseline for an extensive parametric study using the Genetic Algorithm (GA) technique, whereby the effectiveness of practical countermeasures was investigated.

As fuel prices continue to be unstable the drive towards more fuel efficient powertrains is increasing. For engine original equipment manufacturers (OEMs) this means engine downsizing coupled with alternative forms of power to create hybrid systems. Understanding the effect of engine downsizing on vehicle interior NVH is critical in the development of such systems. The objective of this work was to develop a vehicle model that could be used with analytical engine mount force data to predict the vehicle interior noise and vibration response. The approach used was based on the assumption that the largest contributor to interior noise and vibration below 200 Hz is dominated by engine mount forces. An experimental transfer path analysis on a Dodge Ram 2500 equipped with a Cummins ISB 6.7L engine was used to create the vehicle model. The vehicle model consisted of the engine mount forces and vehicle paths that define the interior noise and vibration.

Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) networks within the Intelligent Transportation System (ITS) lead to safety and mobility improvements in vehicle road traffic. This paper presents case studies that support the realization of the ITS architecture as an evolutionary process, beginning with driver information systems for enhancing feedback to the users, semi-autonomous control systems for improved vehicle system management, and fully autonomous control for improving vehicle cooperation and management. The paper will also demonstrate how the automotive, telecom, and data and service providers are working together to develop new ITS technologies.

The Ethanol-Boosted Direct Injection (EBDI) demonstrator engine is a collaborative project led by Ricardo targeted at reducing the fuel consumption of a spark-ignited engine. This paper describes the design challenges to upgrade an existing engine architecture and the synergistic use of a combination of technologies that allows a significant reduction in fuel consumption and CO₂ emissions. Features include an extremely reduced displacement for the target vehicle, 180 bar cylinder pressure capability, cooled exhaust gas recirculation, advanced boosting concepts and direct injection. Precise harmonization of these individual technologies and control algorithms provide optimized operation on gasoline of varying octane and ethanol content.

The problem of predicting the quality of weld is critical to manufacturing. A great deal of data is collected under multiple conditions to predict the quality. The data generated at Daimler Chrysler has been used to develop a model based on grammatical evolution. Grammatical Evolution Technique is based on Genetic Algorithms and generates rules from the data which fit the data. This paper describes the development of a software tool that enables the user to choose input variables such as the metal types of top and bottom layers and their thickness, intensity and speed of laser beam, to generate a three dimensional map showing weld quality. A 3D weld quality surface can be generated in response to any of the two input variables picked from the set of defining input parameters. This tool will enable the user to pick the right set of input conditions to get an optimal weld quality. The tool is developed in Matlab with Graphical User Interface for the ease of operation.

Low frequency torsional vibrations can be a significant source of objectionable vehicle vibrations and in-vehicle boom, especially with changes in engine operation required for improved fuel economy. These changes include lower torque converter lock-up speeds and cylinder deactivation. This paper has two objectives: 1) Examine the effect of increased torsional vibrations on vehicle NVH performance and ways to improve this performance early in the program using test and simulation techniques. The important design parameters affecting vehicle NVH performance will be identified, and the trade-offs required to produce an optimized design will be examined. Also, the relationship between torsional vibrations and mount excursions, will be examined. 2) Investigate the ability of simulation techniques to predict and improve torsional vibration NVH performance. Evaluate the accuracy of the analytical models by comparison to test results.

Brake torque variation is a source of objectionable NVH body/chassis response. Such input commonly results from brake disk thickness variation. The NVH dynamic characteristics of a vehicle can be assessed and quantified through experimental modal testing for determination of mode resonance frequency, damping property, and shape. Standard full vehicle modal testing typically utilizes a random input excitation into the vehicle frame or underbody structure. An alternative methodology was sought to quantify and predict body/chassis sensitivity to brake torque variation. This paper presents a review of experimental modal test methodologies investigated for the reproduction of vehicle response to brake torque variation in a static laboratory environment. Brake caliper adapter random and sine sweep excitation input as well as body sine sweep excitation in tandem with an intentionally locked brake will be detailed.

NVH targets for future vehicles are often defined by utilizing a competitive benchmarking vehicle in conjunction with an existing production and/or reference vehicle. Mode management of full vehicle modes is one of the most effective and significant NVH strategies to achieve such targets. NVH dynamic characteristics of a full vehicle can be assessed and quantified through experimental modal testing for determination of global body mode resonance frequency, damping property, and mode shape. Major body modes identified from full vehicle modal testing are primarily dominated by the vehicle's body-in-white structure. Therefore, an estimate of BIW modes from full vehicle modes becomes essential, when only full vehicle modes from experimental modal testing exist. Establishing BIW targets for future vehicles confines the fundamental NVH behavior of the full vehicle.

This paper describes the application of the modal compliance method to a complex structure such as a vehicle body in white, and the extension of the method from normal modes to the complex modes of a complete vehicle. In addition to the usual bending and torsion calculations, the paper also describes the application of the method to less usual tests such as second torsion, match-boxing and breathing. We also show how the method can be used to investigate the distribution of compliance throughout the structure.

NVH refinement of passenger vehicles is crucial to customer acceptance of contemporary vehicles. This paper describes the vehicle NVH development process, with specific examples from a Diesel sedan application that was derived from gasoline engine-based vehicle architecture. Using an early prototype Diesel vehicle as a starting point, this paper examines the application of a Vehicle Interior Noise Simulation (VINS) technique in the development process. Accordingly, structureborne and airborne noise shares are analyzed in the time-domain under both steady-state and transient test conditions. The results are used to drive countermeasure development to address structureborne and airborne noise refinement. Examples are provided to highlight the refinement process for “Diesel knocking” under idle as well as transient test conditions. Specifically, the application of VINS to understanding the influence of high frequency dynamic stiffness of hydro-mounts on Diesel clatter noise is examined.

The Frequency Response Function (FRF) is a fundamental component to identifying the dynamic characteristics of a system. FRF's have a significant impact on modal analysis and root cause analysis of NVH issues. In most cases the FRF can be easily measured, but there are instances when the measurement is unobtainable due to spatial constraints. This paper outlines a simple experimental method for obtaining a high quality input-output FRF of a structure in areas where an impact hammer can not reach during impact testing. Traditionally, the FRF in such an area is obtained by using a load cell extender with a hammer impact excitation. A common problem with this device is a double hit, that yields unacceptable results.

Tailor welded steel blanks have long been applied in stamping of automotive parts such as door inner, b-pillar, rail, sill inner and liftgate inner, etc. However, there are few known tailor welded aluminum blanks in production. Traditional laser welding equipment simply does not have the capability to weld aluminum since aluminum has much higher reflectivity than steel. Welding quality is another issue since aluminum is highly susceptible to pin holes and undercut which leads to deterioration in formability. In addition, high amount of springback for aluminum panels can result in dimension control problem during assembly. A tailor-welded aluminum blank can help reducing dimension variability by reducing the need for assembly. In this paper, application of friction stir and plasma arc welded blanks on a liftgate inner will be discussed.

This paper identifies the difference in powertrain cooling system content levels using a nominal and a +3 Standard deviation maximum temperature design approach. Variation simulation analysis tools are used along with a 1-D cooling system performance model to predict resulting temperature distribution for different combinations of input variable populations. The analysis will show differential in powertrain cooling system content, mass, and impact to fuel economy for a nominal vs. +3 sigma design approach.