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Ported shroud compressor covers recirculate low momentum air near the inducer blade tips, and the use of these devices has traditionally been confined to extending the low-flow operating region at elevated rotational speeds for compressors on compression-ignition (CI) engines. Implementation of ported shrouds on compressors for spark-ignition (SI) engines has been generally avoided due to operation at pressure ratios below the region where ported shrouds improve low-flow range, the slight efficiency penalty, and the perception of increased noise. The present study provides an experimental investigation of performance and acoustics for a SI engine turbocharger compressor both with a ported shroud and without (baseline). The objective of implementing the ported shroud was to reduce mid-flow range broadband whoosh noise of the baseline compressor over 4-12 kHz.

For diesel engines to meet current and future emissions levels, the amount of EGR required to reach these levels has increased dramatically. This increased EGR has posed big challenges for conventional turbocharger technology to meet the higher emissions requirements while maintaining or improving other vehicle attributes, to the extent that some OEMs resort to multiple turbocharger configurations. These configurations can include parallel, series sequential, or parallel - series turbocharger systems, which would inevitably run into other issues, such as cost, packaging, and thermal loss, etc. This study, as part of a U.S. Department of Energy (USDoE) sponsored research program, is focused on the experimental evaluation of the emission and performance of a modern diesel engine with an advanced single stage turbocharger.

Transient higher-frequency flow-induced tones are often perceived following air-conditioning (A/C) compressor engagements in automotive refrigerant systems, especially the ones with Thermostatic Expansion Valve (TXV) controlled systems. In this paper, the mechanisms of the acoustic tones induced by turbulent flow and shear-layer-instability in A/C lines are presented. Some of the recommended countermeasures for the attenuation and suppression of these flow-induced transient tones are also discussed.

This paper describes the process of incorporation of 25% post-industrial recycled sheet molded composite (SMC) material in the 1998 Continental Hood inner. 1998 Continental Hood assembly consists of traditional SMC outer and this recycled hood inner along with three small steel reinforcements. BUDD Plastics collects SMC scraps from their manufacturing plants. The scrap is then processed and made into fillers for production of SMC. Strength of SMC comes from glass fibers and fillers are added to produce the final mix of raw materials. This recycled material is approximately 10% lighter and less stiff than the conventional virgin SMC. This presented unique challenges to the product development team to incorporate this material into a production vehicle in order to obtain the desired goal of reducing land fill and improving the environment.

For the application of advanced clean combustion technologies, such as diesel HCCI/LTC, a compressor with high efficiency over a broad operation range is required to supply a high amount of EGR with minimum pumping loss. A compressor with high pitch of vaneless diffuser would substantially improve the flow range of the compressor, but it is at the cost of compressor efficiency, especially at low mass flow area where most of the city driving cycles resides. In present study, an ultra low solidity compressor vane diffuser was numerically investigated. It is well known that the flow leaving the impeller is highly distorted, unsteady and turbulent, especially at relative low mass flow rate and near the shroud side of the compressor. A conventional vaned diffuser with high stagger angle could help to improve the performance of the compressor at low end. However, adding diffuser vane to a compressor typically restricts the flow range at high end.

Air-conditioning (A/C) induced moan is a very commonly observed phenomenon in automotive refrigerant systems. Since most of the automotive A/C systems cycle ON/OFF four to six times every minute, the A/C induced moan is quite readily audible under engine idle and even while driving, especially under lower engine/vehicle speeds. It is not unusual for an A/C compressor to moan or not, on some vehicle/s under certain operating conditions. Most of the OEMs resolve or suppress the A/C moan potential to barely audible levels. However, under some unique and extreme operating conditions, A/C moan is quite readily induced and often results in customer complaints. This paper discusses A/C moan related root-causes, sources and paths of propagation. A systematic diagnostic test-procedure is also described to diagnose and develop the needed most cost-effective design-fixes. Finally, based on this case-study - some objective targets are recommended to suppress the A/C moan to acceptable levels.

Custom functions are widely used in real-time embedded automotive applications to conserve scarce processor resources. Typical examples include mathematical functions, filtering routines and lookup tables. The custom routines are very efficient and have been in production for many years [ 1 ]. These hand-crafted functions can be reused in new control algorithm designs being developed using Model Based Design (MBD) tools. The next generation of vehicle control software may contain a mix of both automatically generated software and manually developed code. At Ford Motor Company, the code is automatically generated from control algorithm models that are developed using The MathWorks tool chain. Depending on the project-specific needs, the control algorithm models are automatically translated to efficient C code using either The Math Works Real-Time Workshop Embedded Coder (RTW-EC) or dSPACE TargetLink production code generators.

Vehicle chassis mounted cantilevered components should meet two critical design targets: 1) NVH criterion to avoid resonance with road noise and engine vibration and 2) satisfied durability performance to avoid any incident in structure failure and dysfunction. Generally, two types of testing are performed to validate chassis mounted cantilevered component in the design process: shaker table testing and vehicle proving ground testing. Shaker table testing is a powered vibration endurance test performed with load input summarized from real proving ground data and accurate enough to replicate the physical test. The proving ground test is typically performed at critical milestones with full vehicles. Most tests are simplified lab testing to save cost and effort. CAE procedures that virtually replicate these lab tests is even more helpful in the design verification stages.

The effects of substituting a 12 mm thick subcool on top condenser in place of a 16 mm subcool on bottom condenser are evaluated in a vehicle level AC pull down test. The A to B testing shows that a thinner condenser with subcool on top exhibits no degradation in AC performance while resulting in a lower total system refrigerant charge. The results are from vehicle level tests run in a climatically controlled vehicle level wind tunnel to simulate an AC pull down at 43°C ambient. In addition to cabin temperature and AC vent temperatures, comparison of compressor head pressures was also done. The conclusion of the study was that a standard 16 mm thick subcool on bottom IRD condenser can be replaced by a 12 mm thick subcool on top IRD condenser with no negative effects on performance.

The failure of an A/C system often results in the introduction of contaminants to the A/C system. The sources of the contaminants include debris from damaged components and debris from the surrounding environment. Returning the A/C system to service requires the removal of these contaminants from any reused components. The recommended approach to cleaning contaminated components and systems is to flush with a solvent flushing machine. Previous internal studies have concluded that solvent flushing will remove all contaminants, restoring component and system performance. Many commercial refrigerant recovery and recharge machines include a refrigerant “flush” feature which can flush oil from the system and components with the systems refrigerant. The effectiveness of using the “flush” feature of a refrigerant recovery and recharge machine with an added in-line filter to remove contaminants is investigated.

The natural refrigerant, R744 (CO2), remains a viable solution to replace the high GWP refrigerant R134a which is to be phased out in light-duty vehicles in EU and US market. In this study, thermodynamic analysis is performed on a R744 parallel compression system to evaluate its potential in automotive climate control. The model adopts a correlation of isentropic efficiency as a function of compression ratio based on a prototype R744 MAC compressor and accounts for the operating limits defined in the latest DIN specifications. Optimization is run over typical MAC operating conditions which covers both transcritical and subcritical domain. Comparing to the conventional single compression cycle, effectiveness of parallel compression is found most pronounced in low evaporating temperature and high ambient conditions, with up to 21% increase in COP and 5.3 bar reduction in discharge pressure observed over the considered parametric range.

The Variable Displacement Supercharger (VDS) is a twin helical screw style compressor that has a feature to change its displacement and its compression ratio actively during vehicle operation. This device can reduce the parasitic losses associated with supercharging and improve the relative fuel economy of a supercharged engine. Supercharging is a boosting choice with several advantages over turbocharging. There is fast pressure delivery to the engine intake manifold for fast engine torque response providing the fun to drive feel. The performance delivered by a supercharger can enable engine fuel economy actions to include engine downsizing and downspeeding. The cost and difficulty of engineering hot exhaust components is eliminated when using only an air side compressor. Faster catalyst warm up can be achieved when not warming the turbine housing of a turbocharger.

Turbocharger compressors are susceptible to surge – the instability phenomena that impose limitations on the operation of turbocharged engines because of undesired noise, engine torque capability constraints, and hardware strain. Turbocharged engines are typically equipped with a binary compressor recirculation valve (CRV) whose primary function is to prevent compressor surge. Calibration of the associated control strategy requires in-vehicle tests and usually employs subjective criteria. This work aims to reduce the calibration effort for the strategy by developing a test procedure and data processing algorithms. An automated calibration for CRV control is developed that will generate a baseline calibration that avoids surge events. The effort to obtain the baseline calibration, which can be further fine-tuned, is thereby significantly reduced.

Material authenticity is an important factor for appearance and perceived quality of the vehicle interior. The term authenticity implies ambivalence: For the product designer, it means identification and trueness of the origin of the material. The customers, however, can only access information on the nature of the materials via their own perception of surface features. Thus, the intended authenticity of a material always needs to be conveyed by its surface. Specific cases illustrate the context: 1. The customer touches a part of known matter, but various layers prevent from directly touching the natural material: e.g. leather at the steering wheel, applications of wood. 2. Perception of a thin surface layer indicates authentic material, which is not fulfilled by the whole part: e.g. plastic parts plated with metal. 3. A part consists of authentic material, but newly composed, so that it is not easily identified, such as recycled materials, e.g. leather fiber layers for seats.

A transmission system model is developed at various complexities in order to capture the transient behaviors in drivability and fuel economy simulations. A large number of model parameters bring more degree of freedom to correlate with vehicular test data. However, in practice, it requires extensive time and effort to tune the parameters to satisfy the model performance requirements. Among the transmission model, a hydraulic clutch actuator plays a critical role in transient shift simulations. It is particularly difficult to tune the actuator model when it is over-parameterized. Therefore, it is of great importance to develop a hydraulic actuator model that is easy to adjust while retaining sufficient complexity for replicating realistic transient behaviors. This paper describes a systematic approach for reducing the hydraulic actuator model into a piecewise 1st order representation based on piston movement.

Automotive refrigerant system induced noise and vibration transients usually accompany A/C compressor engagement/disengagement. These transients include audible/perceivable metallic impact/slip (clink, chirp, etc.), engagement thump, delayed accumulator thump, orifice tube/TXV induced hiss, and occasionally very loud slugging. In this paper, the inherent noise source mechanisms of these transients are described, and a set of psychoacoustics based objective metrics quantifying these transients in terms of loudness and sharpness is developed. Some of the recommended design-fixes and noise control approaches for the related transient noises are also discussed.

Response surface methodologies (RSMs) have been proposed as surrogate models in vehicle design processes to gain insight and improve turnaround time for optimization and robust design. However, when studying the vehicle occupants during crash events, nonlinearities in responses, coupled with the relatively high dimensionality of vehicle design, can yield misleading results with little or no warning from the response surface algorithms. To ensure the accuracy and reliability of RSMs, fast and dependable error estimation procedures are essential for enlightening how well a response surface predicts highly nonlinear phenomena, given a limited number of model simulations. Such error estimation methods are also useful for providing guidance on how many simulation runs are needed for reliable RSM construction. In this paper, a fast cross validation error estimate procedure is first presented, applied to the multivariable adaptive regression spline (MARS) response surface method.

To support its recycling efforts, Ford Motor Company is using a Raman based instrument, the RP-1, co-developed with SpectraCode Inc. to identify unknown polymeric parts. Our recycling initiative involves detailed dismantling of our vehicles into individual parts, calculating the percentage recyclability and making recommendations for the future use of recycled polymers. While Ford has voluntarily adopted the SAE J1344 marking protocol for identifying part material composition, a large number of unmarked parts still exist and require identification. This identification is being done with the help of RP-1. To facilitate this identification, we have generated an accurate reference library of Raman spectra for comparison to those of unknown materials. This paper will describe the techniques that were used to develop and refine the RP-1 reference library to identify automotive polymers, especially black/dark plastics.

The current work demonstrates effective suppression of compression system surge instabilities by installing a variable cross-sectional flow area restriction within the inlet duct of a turbocharger centrifugal compressor operating on a bench-top facility. This restriction couples with the compressor, similar to stages in a multi-stage turbomachine, where the effective pressure ratio is the product of those for the restriction and compressor. During experiments at constant compressor rotational speed, the compressor is stable over the negatively sloped portion of the pressure ratio vs. flow rate characteristics, so the restriction is eliminated within this operating region to preserve compressor performance. At low flow rates, the slope of the compressor alone characteristics reaches a positive value, and the unrestricted compression system enters mild surge. Further reduction of flow rate with the unrestricted compressor inlet results in a sudden transition to deep surge instabilities.

The Single Sequential Turbocharger (SST) used in Ford’s 6.7L Scorpion Diesel is analyzed using Computational Fluid Dynamics (CFD) to draw conclusions about the compressor stability at low mass flows. The SST compressor concept consists of a double-sided wheel which flows in parallel fed by two separate inlets (front and rear), followed by a single vane-less diffuser, and a volute. CFD simulations for the full stage are performed at low mass flow rates Both, front and rear, sides have ported shroud casing-treatment (CT) in the inlet region. An objective of the analysis is to determine which side of the SST unit compressor (front or rear on the double-sided wheel) suffers flow break down first as the mass flow is reduced, and its impact on the overall stability of the SST compressor. Another objective is to better understand the interactions between the compressor inlet flow and the flow through the casing-treatment.