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The electrical architecture of today's automobiles employs a significant number of fractional horsepower motors to control wipers, windows, seats, etc. The typical motors are permanent magnet DC brush-commutated motors, often referred to as BM motors. These BM motors, while simple in design, have the inherent issue of creating short-duration, high-frequency electrical noise (caused by the constant interruption, or commutation, of the motor current). This electrical noise can readily lead to radio reception interference. In order to protect against this risk, a typical solution is to install a radio frequency (RF) filter internal to the motor. This filter generally includes a high-frequency ceramic or metal film capacitor across the motor terminals that connect to the vehicle electrical system.

An Extended Range Electric vehicle brings a wealth of new features since it is capable of driving on battery alone, has a range extending engine, and has a high voltage battery pack that can be recharged by plugging into wall power. The customer is able to interact with the vehicle's plug-in charging system through mobile applications. Along with all these new features is the challenge of designing a driver interface to provide important information to the customer. This paper will describe the unique customer interface features added to the vehicle, and will include some additional specifics related to the hardware used to provide the information.

As part of standardizing the global portfolio, General Motors (GM) created an electrical architecture that will support the GM global product feature set. Introduced in 2009, this common electrical architecture is already being applied to multiple platforms in GM's regional engineering centers. The electrical architecture will be updated regularly to address the needs of new features in the automotive market and to take advantage of the latest technology advancements. The functional requirements of these new features result in technology challenges. In addition, many new features may result in challenges to the vehicle electrical architecture or the vehicle development process. The challenges have been evaluated so that needs and initiatives can be better understood.

The development and validation of an electric vehicle presents numerous issues that are not normally encountered during the development of a traditional internal combustion powered vehicle. Many of the issues that are encountered involve components that are common to both electric and internal combustion vehicles but are utilized in new or unique ways that may present challenges during the development process. The integration of the electric motors, power supply, batteries, and associated content into a traditional vehicle can bring new and challenging issues to light. This paper discusses the solution for an issue that arose during the testing and development of the chassis and powertrain hardware of an electric vehicle. In particular, the large rotational inertia of the electric drive motor presented significant challenges when it was accelerated by forces that were external to the drive unit.

Typical seal immersion testing in lubricants does not aerate the lubricant as typically seen during normal operation of a transmission or axle. This paper will discuss a new test apparatus that introduces air into transmission fluids and gear oils during seal immersion testing. The seal materials selected for the testing are from current vehicle applications from several different material families. The test results compare the standard properties: change in tensile strength, elongation, hardness, and volume swell. Several tests were completed to investigate and refine the new testing method for seal compatibility testing with transmission fluids and gear oils. Initial results from the first data sets indicate that lubricant aeration helps improve test repeatability. In addition to aeration, the test results explore appropriate fluid immersion temperature for repeatability and appropriate test duration.

1 As global automotive manufacturers prepare for the introduction of HFO-1234yf as the low Global Warming Potential (GWP) refrigerant solution in Europe and North America concerns over compressor durability due to oil migration still remain. This preliminary study evaluates several different variables that affect oil migration. Several compressor suppliers each having their own unique oil formulation for HFO-1234yf were included. Comparisons between vehicle tests and various accelerated lab test methods are made. In R134a automotive system the thresholds that cause compressor warranty are well understood. This study will compare AC systems running with HFO-1234yf at the same time identical systems with R134a are run to understand the relative effect of HFO-1234yf versus R134a.

This study introduces a method to examine the flow path of the lubricant inside a planetary gearset of an automatic transmission. A typical planetary gearbox has several load bearing elements which are in relative sliding motion to each other which causes heat to be released. The major sources of friction as well as heat are the meshing teeth between gears (sun/planet, planet/ring), thrust washers, thrust bearings and needle bearings. The lubricant performs the vital function of both lubricating these sliding interfaces and cooling these sources of heat, thereby preventing failure of the gearbox. The exact flow path that the lubricant takes inside a planetary gearset is unknown. Since the gearset is primarily splash lubricated, it is also not known how much lubricant reaches critical areas. A method is developed using computational fluid dynamic techniques to enable comprehensive flow and thermal analysis and visualization of an automatic transmission assembly.

In an effort to increase fuel economy and improve shift quality - the GF6 family of General Motors transmissions has been analyzed for potential enhancements. The focus of this analysis was to improve fuel economy, while increasing downshift responsiveness, and manual mode sport delays. This paper describes a variety of the hardware philosophy changes, and control methods which have contributed to the next generation of GM clutch-to-clutch 6-speed transmissions. These changes to hardware and controls have led to a composite fuel economy improvement of 4.5% with no changes to shift or torque-converter scheduling. In addition, the downshift responsiveness has been significantly improved to reduce delay times by approximately 50% while virtually eliminating the dependency on engine torque reductions - ultimately allowing for stacked downshifts to progress with minimal, if any, time between shifts. Additionally, “tap shift” delays have been significantly decreased to levels near 150 ms.

Measured vehicle loads have traditionally been used as the basis for development of component, subsystem and vehicle level durability tests. The use of measured loads posed challenges due to the availability of representative hardware, scheduling, and other factors. In addition, stress was placed on existing procedures and methods by aggressive product development timing, variety in tuning and equipment packages, and higher levels of design optimization. To meet these challenges, General Motors developed new processes and technical competencies which enabled the direct substitution of analytically synthesized loads for measured data. This process of Virtual Road Load Data Acquisition (vRLDA) enabled (a) conformance to shortened product development cycles, (b) greater consistency between design targets and validation requirements, and (c) more comprehensive data.

The SAE J2716 SENT (Single Edge Nibble Transmission) Protocol has entered production with a number of announced products. The SENT protocol is a point-to-point scheme for transmitting signal values from a sensor to a controller. It is intended to allow for high resolution data transmission with a lower system cost than available serial data solution. The SAE SENT Task Force has developed a number of enhancements and clarifications to the original specification which are summarized in this paper.

An air suspension system can consist of many different components. These components include an air compressor, air springs, pneumatic solenoid valves, height sensors, electronic control unit, air reservoir, air lines, pressure sensor, temperature sensor, etc. The system could be designed as a 2-corner rear air suspension or a 4-corner air suspension. In this paper, the pneumatic models of air suspension systems are presented. The suspension system models are implemented in AmeSim. The suspension controls are implemented using Matlab/Simulink. The compressor was modeled using the standard AmeSim element with known mass flow rate as a function of pressure ratio. Air lines were modeled using a friction submodel of pneumatic pipe and control (isolation) valves are modeled using 2 position, 2 port pneumatic servo valves. The air spring is modeled as a single pneumatic chamber, single rod jack with spring assistance to account for spring nonlinearities.

In general for Vehicle-to-Vehicle (V2V) communication, message authentication is performed on every received wireless message by conducting verification for a valid signature, and only messages that have been successfully verified are processed further. In V2V safety communication, there are a large number of vehicles and each vehicle transmits safety messages frequently; therefore the number of received messages per second would be large. Thus authentication of each and every received message, for example based on the IEEE 1609.2 standard, is computationally very expensive and can only be carried out with expensive dedicated cryptographic hardware. An interesting observation is that most of these routine safety messages do not result in driver warnings or control actions since we expect that the safety system would be designed to provide warnings or control actions only when the threat of collision is high.

Ferritic Nitrocarburized (FNC) cast iron brake rotors are proposed as a means to improve corrosion resistance, improve brake lining wear, as well as reduce corrosion-induced pulsation of automotive brake rotors. FNC processing of finish machined brake rotors presents challenges with controlling distortion, i.e., lateral run out (LRO). Prior investigations of FNC brake rotors suggested grinding the rotors to correct distortion. Post grinding the FNC processed rotors may reduce the FNC layer with an accompanying reduction in performance. Stress relieving (SR) the casting prior to FNC was found beneficial in providing a dimensionally acceptable rotor. Dimensional analysis of the stress relieved and FNC processed rotors will be presented. Benefits of FNC processed rotors will be reviewed.

The two-mode hybrid system has several advantages over a one-mode EVT system: greater ability to transmit power mechanically and minimize electrical recirculation power, maximize fuel economy improvement and best meet demanding vehicle requirements. Extending the two-mode hybrid electric vehicle (HEV) to two-mode plug-in hybrid electric vehicle (PHEV) is significant not only to make the internal combustion engine (ICE)-based vehicle cleaner and more efficient in the near term, but also to provide a potential path to battery electric vehicles in the future. For PHEV, the enhanced electric drive capability is of vital importance to achieve best efficiency and best electric only performance. This paper describes the development of a prototype two-mode hybrid powertrain with enhanced EV capability (2MH4EV). The prototype drive unit includes an additional input brake to the existing General Motors FWD 2-mode HEV system.

The ride performance potentials of a prototype torsio-elastic axle suspension for an off-road vehicle were investigated analytically and experimentally. A forestry vehicle was fitted with the prototype suspension at its rear axle to assess its ride performance benefits. Field measurements of ride vibration along the vertical, lateral, fore-aft, roll and pitch axes were performed for the suspended and an unsuspended vehicle, while traversing a forestry terrain. The measured vibration responses of both vehicles were evaluated in terms of unweighted and frequency-weighted rms accelerations and the acceleration spectra, and compared to assess the potential performance benefits of the proposed suspension. The results revealed that the proposed suspension could yield significant reductions in the vibration magnitudes transmitted to the operator's station.