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Downsized-Boosted Gasoline Engine with Exhaust Compound and Lean Advanced Combustion

General Motors LLC-Jeremie Dernotte, Paul M. Najt, Russell P. Durrett
  • Technical Paper
  • 2020-01-0795
To be published on 2020-04-14 by SAE International in United States
This article presents the experimental results obtained with a disruptive engine platform, designed to maximize the engine efficiency through a synergetic implementation of downsizing, high compression-ratio, and importantly exhaust-heat energy recovery in conjunction with advanced lean/dilute low-temperature type combustion. The engine architecture is a supercharged high-power output, 1.1-liter engine with two-firing cylinders and a high compression ratio of 13.5:1. The integrated exhaust heat recovery system is an additional, larger displacement, non-fueled cylinder into which the exhaust gas from the two firing cylinders is alternately transferred to be further expended. The main goal of this work is to implement advanced lean/dilute combustion while minimizing NOx emissions and addressing the transition between the operating modes. The combustion modes include well-mixed charge compression-ignition at low-load, and a mixed-mode combustion strategy at higher loads. The mixed-mode combustion strategy is composed of a deflagration of a stratified mixture, triggering a controlled autoignition of the surrounding gas. The paper describes the key features of the engine and details regarding the combustion and multi-mode valve strategies. The experiments were performed under steady-state…
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General Motors Full Scale Wind Tunnel Upgrade

General Motors LLC-Nina Tortosa
Jacobs Technology-Paul Nagle, Tyler Brooker
  • Technical Paper
  • 2020-01-0687
To be published on 2020-04-14 by SAE International in United States
The General Motors Aero Lab’s Full Scale Wind Tunnel Facility, which came into operation in August of 1980, has undergone the significant upgrade of installing a state-of-the-art moving ground plane system. After almost four decades of continued use the full-scale wind tunnel also received some significant maintenance to other areas, including a new heat exchanger, main fan overhaul, and replacement of the test section acoustic treatment. A 5-belt system was installed along with an integrated vehicle lift system. The center belt measures 8m long, and can accommodate two belt widths of 1100mm and 900mm. Flow quality and other wind tunnel performance parameters were maintained to prior standards which are on par with the latest industry standards. The new 5-belt rolling road system maintains GM’s industry leading vehicle aerodynamic development and the improved acoustic panels ensure GM continues to develop vehicles with leading class acoustics.
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Study of the Effective Backlight Angle Influence on Vehicle Aerodynamics and Contamination

General Motors LLC-Danilo Oliveira
University of Campinas-Rogerio Goncalves dos Santos
  • Technical Paper
  • 2020-01-0691
To be published on 2020-04-14 by SAE International in United States
This paper presents contamination simulation results of a 2004 Chevrolet Malibu Maxx with different morphed rear declination angles geometry to understand that effect on the vehicle contamination. Computational fluid dynamics highly-resolved time accurate simulations were performed using a commercial Lattice-Boltzmann solver, to compare the rear end contamination with five different rear declination angles. Aerodynamics simulations were also performed and presented good correlation with theoretical data. The contamination results were compared with aerodynamics simulation results in order to find a trend between the two areas for different declination angles.
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Development of GM 10-Speed Allison Heavy Duty (HD) Transmission

General Motors LLC-Chi Teck Lee, David Ames, Brett Caldwell, Matthew Knoth, Timothy Reinhart, Jeffrey Kelly, Rajesh Kannan, German Tanasi
  • Technical Paper
  • 2020-01-0438
To be published on 2020-04-14 by SAE International in United States
This paper describes the development of GM 10-Speed Allison Heavy Duty (HD) Transmission. The trend of engine power and towing capacity in the automotive heavy-duty truck segment has been steadily climbing for a past 10 years. The development of GM 10-Speed Allison Heavy Duty Transmission is designed to be best in class for towing performance with no compromise in fuel economy. GM 10-Speed Allison Heavy Duty Transmission also gives the customers the option to order an integrated power transfer unit to improve the installation of power transfer or generation accessories. GM Allison HD truly brings the best of towing performance and fuel economy to the customers.
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Minimizing Disturbance Detection Time in Hydraulic Systems

General Motors LLC-Paul Otanez, Ramadityanand Bhogadi
  • Technical Paper
  • 2020-01-0263
To be published on 2020-04-14 by SAE International in United States
In a hydraulic system, parameter variation, contamination, and/or operating conditions can lead to instabilities in the pressure response. The resultant erratic pressure profile produces reduced performance that can lead to hardware damage. Specifically, in a transmission control system, the inability to track pressure commands can result in various types of slip and disturbances to the driveline. Therefore, it is advantageous to identify such pressure events and take remedial actions. The challenge is to detect the condition in the least amount of time while minimizing false alarms. In this study, cross and auto-correlation techniques are evaluated for the detection of pressure disturbances. The performance of the detectors is measured in terms of speed of detection and robustness to: 1) measurement noise, and 2) disturbance parameter uncertainty (frequency and amplitude). The implications in terms of computations and memory utilization of implementing the detectors in real-time embedded systems are also discussed. Both simulation and hardware examples are presented. The hardware experiment is performed in a hydraulic system with low damping composed of a solenoid and a regulator valve…
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Leveraging real-world driving data sets for design and impact evaluation of energy efficient control strategies.

General Motors LLC-Bharatkumar Hegde, Steven E. Muldoon
National Renewable Energy Laboratory-Michael O'Keefe, Jeffrey Gonder
  • Technical Paper
  • 2020-01-0585
To be published on 2020-04-14 by SAE International in United States
Modeling and simulation are crucial in the development of advanced energy efficient control strategies. Utilizing real-world driving data as the underlying basis for control design and simulation lends veracity to projected real-world energy savings. Standardized drive cycles are limited in their utility for evaluating advanced driving strategies that utilize connectivity and on-vehicle sensing, primarily because they are non-causal and are typically intended for evaluating emission and fuel economy under controlled conditions. Real-world driving data, because of its scale, is a useful representation of various road types, driving styles, and driving environments. The scale of real-world data also presents challenges in effectively using it in simulations. A fast and efficient simulation methodology is necessary to handle the large number of simulations performed for design analysis and impact evaluation of control strategies. In this study, we present two methods of leveraging real-world data in both design optimization of energy efficient control strategies and in evaluating the real-world impact of those control strategies upon large-scale deployment. Through these methodologies, strategies with highest impact on energy savings were selected…
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Random Vibration Fatigue Life Assessment of Transmission Control Module (TCM) Bracket Considering the Mean Stress Effect

General Motors LLC-Neeraj Carpenter, Sudeep Yesudas, Michael D. Nienhuis
  • Technical Paper
  • 2020-01-0194
To be published on 2020-04-14 by SAE International in United States
Random loads are experienced by many engineering systems/components such as the housing and the brackets mounted on the chassis of an automobile, wind blowing on the wind turbine blades, Printed Circuit Board (PCB) used in battery electric vehicles, fuel cell stacks mounted on housing of a fuel cell etc. In automotive systems, random load is caused due to unevenness of the road surface. As these loads are varying in nature, it could lead to the fatigue failure of systems experiencing such loads. To ensure structural integrity, they are designed considering random loads and commercially used FE software packages have the capabilities available to evaluate random vibration fatigue. While above mentioned systems undergo random loads during operation, there are other loads/stresses also acting on them such as assembly loads (bolt preload), residual stresses due to casting, static loads i.e. load due to belt or chain drive etc. Consideration of all significant loads are extremely important for a design engineer and CAE analyst while designing such systems in order to ensure the reliability of their design. The…
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EDGE-QUALITY EFFECTS ON MECHANICAL PROPERTIES OF STAMPED NON-ORIENTED ELECTRICAL STEEL

General Motors LLC-Peggy Jones, Margarita Thompson, Yew Sum Leong, Paul Crepeau
General Motors Technical Center India-Virupakshappa Lakkonavar, Swaroop Kavi
  • Technical Paper
  • 2020-01-1072
To be published on 2020-04-14 by SAE International in United States
The market for electric vehicles and hybrid electric vehicles is expected to grow in the coming years, which is increasing interest in design optimization of electric motors for automotive applications. Under demanding duty cycles, the moving part within a motor, the rotor, may experience varying stresses induced by centrifugal force, a necessary condition for fatigue. Rotors contain hundreds of electrical steel laminations produced by stamping, which creates a characteristic edge structure comprising rollover, shear and tear zones, plus a burr. Fatigue properties are commonly reported with specimens having polished edges. Since surface condition is known to affect fatigue strength, an experiment was conducted to determine the effect of sample preparation in stamped specimens. Tensile properties were unaffected by polishing. In contrast, polishing was shown to increase fatigue strength by approximately 10-20% in the range of 105-107 cycles to failure.
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Improving EV customer experience using Sound Enhancement

General Motors LLC-Frank Valeri, Glenn Pietila
  • Technical Paper
  • 2020-01-1361
To be published on 2020-04-14 by SAE International in United States
Electric Vehicles are typically thought of as being quiet and refined, but they do come with some unique N&V challenges. Some of these challenges include a natural sound that can be undesirable due to its tonal nature, presence of high frequency, discontinuities in sound, and characteristics and levels that do not always naturally increase with motor torque and vehicle speed. One approach to address those challenges is Electric Vehicle Sound Enhancement (EVSE) which is a software feature embedded within the infotainment system. EVSE can be used to improve the perception of the vehicle by enhancing the preferred natural sounds of the vehicle, masking unusual and annoying components of the sound and aurally conveying information related to the vehicle performance. A jury study was conducted to better understand how EVSE can be used to accomplish this. This paper will summarize a typical EVSE system and highlight some of the tools and methods that can be used to develop an EVSE tuning that mitigates the unpleasant sounds and enhances the customer experience without completely changing the vehicle…
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N&V Component Structural Integration and Mounted Component Durability Implications

General Motors LLC-Mark Stebbins, Joseph Schudt
  • Technical Paper
  • 2020-01-1396
To be published on 2020-04-14 by SAE International in United States
Exterior component integration has presented competing integration challenges for suitable exterior styling, safety, N&V structural feel and component durability balanced performances. Industry standard practice of N&V vehicle mode mapping uses vehicle source, path and receiver considerations for component mode frequency placement. Mounted component mode frequency performance can have an influence on structural feel and durability performances. Component integration headwinds have increased with additional nonstructural component styling content, component size, component mass and added sensor modules. Based on first principles, the effective mass of exterior mounted components are increased due to the geometric overhang from structure. Component input vibration levels are compounded due to the cantilevered nature as well as relative positioning to the suspension and propulsion vehicle source inputs locations. Examples of vehicle end mounted components include but are not limited to headlamps, side mirrors, end gates, bumpers and fascia. Our goal is to establish basic expectations for the behavior of these systems, and ultimately to consolidate our existing rational and approaches that can be applied to such integrated systems. The focus of this paper…