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The present production General Motors 2-Mode Hybrid system for full-size SUVs and pickup trucks integrates truck utility functions with a full hybrid system. The 2-mode hybrid system incorporates two electro-mechanical power-split operating modes with four fixed-gear ratios. The combination provides fuel savings from electric assist, regenerative braking and low-speed electric vehicle operation. The combination of two power-split modes reduces the amount of mechanical power that is converted to electric power for continuously variable transmission operation, meeting the utility required for SUVs and trucks. This paper describes how fuel economy functionality was blended with full-size truck utility functions. Truck functions described include: Manual Range Select, Cruise Control, 4WD-Low and continuous high load operation.

It is a well established fact that variable camshaft phasing can be used to reduce engine out emissions during steady state operation. However, a transition in camshaft timing which often accompanies engine speed / load changes, can have a significant dynamic impact on volumetric efficiency. The change in volumetric efficiency can be highly unpredictable, and can last for several engine cycles following the endpoint of cam movement. Since precise control of catalyst feedgas equivalence ratio is crucial to meeting increasingly stringent automotive emission requirements, the steady state benefits of cam phasing can be overshadowed by the loss of A/F control during transient operation if the engine control algorithms are not properly designed and calibrated. This paper investigates the impact of exhaust variable cam phaser transients on equivalence ratio control, and the mechanism by which volumetric efficiency is affected.

This paper describes the creation of novel transmission mechanisms using algebraic design techniques. The objective is to create novel arrangements comprised of one or more planetary gear sets, a pair of motor-generators and several torque-transmitting mechanisms (clutches and brakes). The algebraic design procedure represents the planetary gear sets, fixed interconnections, clutches/brakes, and motor-generator sets as algebraic constraints. Appropriate subsets of constraint equations are solved to identify viable transmission mechanism designs. We have used the above design approach to create several novel candidate multi-speed transmissions as well as EVT concepts. The main benefit of the algebraic design procedure is that it allows the designer to systematically generate and assess novel designs.

Current Diesel engines development is facing challenging vibro-acoustic requirements and at the same time is struggling with the need to reduce as much as possible the cost and the weight of the engine. The latter obviously has become a key player for fuel consumption reduction. Large covers are commonly used in the base engine design and their noise contribution to total radiated noise is not negligible. Typical covers architecture shows thick cast and ribbed plates, meaning heavy and expensive covers. An interesting option is represented by using thin stamped covers either in aluminum or in steel, that have to show a low vibrational response. The current paper focuses on the structural optimization of such a peculiar design, trying to mitigate as much as possible its noise radiation with the intent to avoid any additional acoustic enabler (e.g. wrapping by means of acoustic foams) that will increase the final cost of the component.

Sound power can be determined using a variety of methods, but precision methods require the volume of the noise source to be less than 1% of the chamber volume leading to relatively large test chambers. Automotive torque converter performance and noise testing is completed in an enclosed metallic test fixture which inhibits the use of precision methods due to volume and space limitations. This paper describes a new method developed to accurately determine sound power of an automotive torque converter in a relatively small enclosure through characterization of the test environment. The test environment was characterized using two reference noise sources designed to represent torque converter noise output and physical geometry. Sound pressure levels of the sources were measured at multiple microphone locations and at three source amplitude levels to characterize the environment.

This paper describes how distributive computing along with statistical subsystem simulation can be applied to produce near production ready embedded vehicle software and calibrations. Coupling distributive computing and statistical simulation was first employed over a decade ago at General Motors to design and analyze propulsion subsystem hardware. Recently this method of simulation has been enhanced extending its capabilities to both test embedded vehicle code as well as develop calibrations. A primary advantage of this simulation technique is its ability to generate data from a statistically significant population of subsystems. The result is the acquisition of an optimal data set enabling the development of a robust design now including both embedded code and calibrations. Additionally it has been shown that there are significant economic advantages in terms of time and cost associated with this type of development when compared to traditional method.

This work reports a CFD study on a 2-stroke (2-S) opposed piston high speed direct injection (HSDI) Diesel engine. The engine main features (bore, stroke, port timings, et cetera) are defined in a previous stage of the project, while the current analysis is focused on the assembly made up of scavenge ports, manifold and cylinder. The first step of the study consists in the construction of a parametric mesh on a simplified geometry. Two geometric parameters and three different operating conditions are considered. A CFD-3D simulation by using a customized version of the KIVA-4 code is performed on a set of 243 different cases, sweeping all the most interesting combinations of geometric parameters and operating conditions. The post-processing of this huge amount of data allow us to define the most effective geometric configuration, named baseline.

The purpose of this paper is to present the origins and the technology of the different types of non-manual transmissions systems currently available and the wide potential to incorporate such technologies to the vehicles made in Brazil. The Brazilian market is experiencing a huge increase in automated and automatic transmissions vehicles share, and the OEMs are adopting different strategies to offer competitive products with affordable prices to enter in this segment. Many different alternatives are available, and there is no obvious winner. This paper will describe the concepts, the architecture and the operations of such systems and point out the pros and cons of each one.

Low Voltage Electric Drives are becoming very attractive for various applications in the Turf, Construction and Agricultural products being engineered today. Determining what the Customer Support Requirements are for Maintenance and Repair for the Life Cycle of the products is critical to the initial design process. Presenter Russell Christ

With the ability of modern high pressure diesel injectors to deliver accurate, closely coupled multiple pulse injections, it is possible to minimize engine combustion noise without negative effect on exhaust emissions. Literature shows that, splitting the cycle heat release into several parts helps to lower peak heat release rate and combustion noise. The charge cooling caused by fuel vaporization can be effectively used to influence ignition delay and achieve lower noise, emissions and fuel consumption. With the traditional pilot-main injection scheme, researchers have shown that, the injection dwell time between the pilot and main is primarily responsible for noise reduction. The current objective is to analytically explore the fundamental physics behind the experimentally observed noise reduction phenomena with multiple injections. This computational study was conducted at a key part-load operation (2000RPM and 5Bar BMEP) with five injection pulses.

Using a clutch to disconnect and shut-off the engine when engine power is not required, the single-motor strong hybrid has the potential for significant fuel economy improvement with reduced costs and less system complexity. However, it is a challenge for the single-motor strong hybrid to maintain acceptable drivability at engine start since it requires diverting motor torque through a slipping clutch to start the engine. In this study, dynamic simulations of the hybrid transmission driveline with hydraulic and motor controls have been employed to assess the feasibility of the single-motor strong hybrid, to address drivability issues specific to this hybrid architecture at engine start, and to develop control methods to manage driveline disturbances to an acceptable level.

High interest is expressed in using analytical models to eliminate costly driveline tests used to determine the stresses produced in the driveshaft and driveline during resonant operating conditions. This paper discusses an analytical model to simulate the driveline-bending integrity, test procedure. Three major subsystems are modeled in this analytical approach, namely powertrain, rear axle, and driveshaft. Imbalance masses were added on the driveshaft to induce the whirl motion of the driveshaft. The combination of nonlinear Multi-body System Simulation (MSS) and linear Finite Element Analysis (FEA) in the time domain was employed for the evaluation of the dynamic interaction between several parts.

Wire shorts on an in-vehicle controller area network (CAN) impact the communication between electrical control units (ECUs), and negatively affects the vehicle control. The fault, especially the intermittent fault, is difficult to locate. In this paper, an equivalent circuit model for in-vehicle CAN bus is developed under the wire short fault scenario. The bus resistance is estimated and a resistance-distance mapping approach is proposed to locate the fault. The proposed approach is implemented in an Arduino-based embedded system and validated on a vehicle frame. The experimental results are promising. The approach presented in this paper may reduce trouble shooting time for CAN wire short faults and may enable early detection before the customer is inconvenienced.

The VT25-E transmission introduced by General Motors for the 2002 model year is the first variant of GM VTi variable transmission family. The VTi is an electronically controlled Continuously Variable Transaxle (CVT). It is the first North American, high volume production CVT. This CVT enables fuel economy improvements over traditional step gear transmissions, with an improved packaging, wider ratio spread, neutral idle and complete absence of shifts for driver comfort. The VT25-E utilizes a controlled slip converter clutch in conjunction with electronically scheduled ratios and an integrated electronic throttle control to operate the powertrain at its most efficient level. A dual-lobed fixed displacement vane pump and jet nozzle filter arrangement provide the source pressure to a multi-tiered hydraulic control system. The multi-tiered hydraulic control system helps to achieve the precise control necessary to meet the durability requirements of this demanding market.

The 4T65-E transmission produced by General Motors is the third evolution of GM's original 4-speed F.W.D. automatic. This most recent redesign introduced for the 1997 model year meets new corporate goals for fuel economy and reduced noise, along with the ability to adjust shift character to meet the brand image of the various nameplates. Improving fuel economy and cooling at increased engine power levels was enabled by designing a larger diameter torque converter with the aid of 3-D modeling. The new converter has reduced internal leakage and incorporates a controlled slip clutch. Improvements in NVH have been achieved through a revised oil pump design and the use of the new phased drive chain, made affordable by the joint development of powdered metal technology required for the unique sprocket design.

This study is an experimental and computational investigation of the influence of injection timing, fuel spray orientation, and in-cylinder air motion on the combustion, fuel economy, and engine-out emissions of a single-cylinder, 2-valve, spark-ignition direct-injection (SIDI) engine, operating under stratified-charged conditions. For the best compromise between fuel consumption, combustion stability, engine-out hydrocarbon emissions and smoke, the engine required relatively retarded injection timings (in comparison to other charge- or wall-controlled DI engines), high swirl levels, and a spray orientation that is directed towards the intake-valve side and targets the ridge wall of the piston.

Carbon, hydrogen and oxygen are major elements in vehicle fuels. Knowledge of fuels elemental composition is helpful in addressing its performance characteristics. Carbon, hydrogen and oxygen composition is an important parameter in engine calibration affecting vehicle performance, emissions and fuel economy. Biodiesel, a fuel comprised of mono-alkyl esters of long-chain fatty acids also known as Fatty Acid Methyl Esters(FAME), derived from vegetable oils or animal fats, has become an important commercial marketplace automotive fuel in the United States (US) and around the world over last few years. FAME biodiesels have many chemical and physical property differences compared to conventional petroleum based diesel fuels. Also, the properties of biodiesel vary based on the feedstock chosen for biodiesel production. One of the key differences between petroleum diesel fuels and biodiesel is the oxygen content.

The aim of the present study is to improve the effectiveness of automotive diesel engine and aftertreatment calibration process through the critical evaluation of several methodologies to estimate the soot mass flow produced by diesel engines fueled by petroleum fuels and filtered by Diesel Particulate Filters (DPF). In particular, its focus has been the development of a reliable simulation method for the accurate prediction of the engine-out soot mass flow starting from Filter Smoke Number (FSN) measurements executed in steady state conditions, in order to predict the DPF loading considering different engine working conditions corresponding to NEDC and WLTP cycles. In order to achieve this goal, the study was split into two main parts: Correlation between ‘wet PM’ (measured by soot filter weighing) and the ‘dry soot’ (measured by the Micro Soot Sensor MSS).

The process and the tools that are used for engineering an optimum engine air-flow subsystem are critical for the successful execution of an engine program. From the perspective of the Air-Flow Subsystem Engineer, the requirements and concept subsystem of components, component subsystem, engine subsystem, and vehicle system engineering processes are described. Additionally, applicable tools such as benchmarking, engine cycle simulation, vehicle simulation, computational fluid dynamics, steady air-flow bench, engine dynamometer, and vehicle testing are explained. As an example, this paper illustrates the process by which a modern, high-performance, high-volume production-intent engine air-flow subsystem, in particular, the intake manifold component, is engineered and how these tools are applied.

Carbon, hydrogen and oxygen are major elements in modern fuels. Varying combinations of these elements in motor fuel alter the stoichiometric air-fuel ratio (A/F). Stoichiometric A/F ratio is an important parameter in engine calibration affecting vehicle performance, emissions and fuel economy. With increasing use of ethanol in automotive fuels in recent years, since it can be made from renewable feedstocks, oxygen contents in fuel are increasing. Oxygen contents can be around 1.7 mass % in European E5 gasoline or 3.5 mass % in U.S. E10 gasoline and up to 29 mass % in E85 fuel. The increase in oxygen content of fuel has resulted in changes in other physical and chemical properties due to the differences between ethanol and hydrocarbons refined from fossil oil. A previous paper (SAE 2010-01-1517) discussed the change in energy content of automotive fuel and the estimation of net heating values from common fuel properties.