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OBD system requirements were first developed by the California Air Resources Board, the U.S. Environmental Protection Agency, and the European Commission. New OBD requirements should be as consistent as possible with existing requirements to maximize reliability and to minimize system complexity, proliferation of configurations, and consumer cost. New OBD requirements from around the world are briefly reviewed and most are consistent with the original U.S. and European requirements. Worldwide OBD requirements are being further harmonized under the United Nations, Economic Commission for Europe, World Forum for Harmonization of Vehicle Regulations (WP29). Presenter David H. Ferris, General Motors Company

Plug-In Hybrid and Extended Range Electric Vehicle's have quickly become the focus of many OEM's and suppliers. Existing regulations and test procedures did not anticipate this rapid adoption of this new technology, resulting in many product development challenges. The lack of clear requirements is further complicated by CARBs consideration of CO2 inclusion in their next light duty OBD regulation. This presentation provides an overview of the regulatory requirements for OBD systems on hybrid vehicles that intend to certify in California. Near term challenges for EREV?s and PHEV?s are discussed, including concerns with the existing denominator and warm-up cycle calculations. Some proposals are made to address these concerns. Presenter Andrew Zettel, General Motors Company

A combination of laboratory reactor measurements and vehicle FTP testing has been combined to demonstrate a method for diagnosing the formation of NO2 from a diesel oxidation catalyst (DOC). Using small cores from a production DOC and simulated diesel exhaust, the laboratory reactor experiments are used to support a model for DOC chemical reaction kinetics. The model we propose shows that the ability to produce NO2 is chemically linked to the ability of the catalyst to oxidize hydrocarbon (HC). For thermally damaged DOCs, loss of the HC oxidation function is simultaneous with loss of the NO2 production function. Since HC oxidation is the source of heat generated in the DOC under regeneration conditions, we conclude that a diagnostic of the DOC exotherm is able to detect the failure of the DOC to produce NO2. Vehicle emissions data from a 6.6 L Duramax HD pick-up with DOC of various levels of thermal degradation is provided to support the diagnostic concept.

Previous research has shown that elevating fuel injection pressure results in better air-fuel mixture formation, allowing for a further increase in maximum exhaust gas recirculation (EGR) rate while consequently reducing NOx emissions. The aim of this paper is to find out whether there is an optimum injection pressure for lowest soot-NOx emissions at a given boost pressure in high-speed diesel engines. Experiments are carried out on a single-cylinder research engine with a prototype common-rail system, capable of more than 200 MPa injection pressure. The effect of injection pressure on soot-NOx formation is investigated for a variety of boost conditions, representing the conditions of single to multi-stage turbocharger systems. Analysis of the data is performed at the application relevant soot to NOx ratio of approximately 1:10. It is observed that above a critical injection pressure, soot-NOx emissions are not reduced any further.

Magnesium and aluminum alloys offer lightweighting opportunities in automotive applications. Joining of dissimilar materials, however, generally requires methods that do not involve fusion. This paper explores the use of self-pierce riveting (SPR) to join magnesium to aluminum alloys for structural and closure applications. The preliminary results indicate that SPR is a viable option for joining aluminum extrusions to magnesium die castings, as well as stamped sheet aluminum to quick-plastic-formed (QPF) sheet magnesium.

Experimental decklids for the Cadillac STS sedan were made with Al AA5083 sheet outer panels and Mg AZ31B sheet inner panels using regular-production forming processes and hardware. Joining and coating processes were developed to accommodate the unique properties of Mg. Assembled decklids were evaluated for dimensional accuracy, slam durability, and impact response. The assemblies performed very well in these tests. Explicit and implicit finite element simulations of decklids were conducted, and showed that the Al/Mg decklids have good stiffness and strength characteristics. These results suggest the feasibility of using Mg sheet closure panels from a structural perspective.

Organic acid degradation products and other anions in engine oil were speciated by capillary electrophoresis (CE) and liquid chromatography-mass spectrometry (LCMS) with electrospray ionization. The sample preparation procedure involved selectively extracting the acids and other water soluble salts into 0.05M aqueous potassium hydroxide. Samples of engine-aged mineral oil and synthetic engine oil contained formic acid, acetic acid, and complex mixtures of fatty acid degradation products. CE analysis of formic acid, acetic acid and selected fatty acids is proposed as a new chemical analysis method for evaluating the condition of engine oil and for studying the effects of high temperature-high load (HTHL) oxidation. Because the overall pattern of CE peaks in the electropherogram changes with oil age or condition, CE-fingerprint (i.e., pattern recognition) techniques may also be useful for evaluating an aged oil's condition or remaining service life.

Regarding the strongly growing two-wheeler market fuel economy, price and emission legislations are in focus of current development work. Fuel economy as well as emissions can be improved by introduction of engine management systems (EMS). In order to provide the benefits of an EMS for low cost motorcycles, efforts are being made at BOSCH to reduce the costs of a port fuel injection (PFI) system. The present paper describes a method of how to reduce the number of sensors of a PFI system by the use of sophisticated software functions based on high-resolution engine speed evaluation. In order to improve the performance of a system working without a MAP-sensor (manifold air pressure sensor) an air charge feature (ACFn) based on engine speed is introduced. It is shown by an experiment that ACFn allows to detect and adapt changes in manifold air pressure. Cross-influences on ACFn are analyzed by simulations and engine test bench measurements.

Fuel economy of two-wheelers is an important factor influencing the purchasing psychology of the consumer within the emerging markets. Additionally, air pollution being a major environmental topic, there is a rising concern about vehicle emissions, especially in the big cities and their metropolitan areas. Potentially, the relatively expensive engine management systems are providing more features and value in comparison to the carburettor counterpart. The combustion system analysis is carried out on a 125 cm3 motorcycle engine and the subsequent numerical simulation comparing the carburettor and the Electronic (Port) Fuel Injection which provides a basis to establish the fuel consumption benefit for the electronic injection systems [1].

In order to comply with more and more stringent emission standards, like EU6 which will be mandatory starting in September 2014, GDI engines have to be further optimized particularly in regard of PN emissions. It is generally accepted that the deposition of liquid fuel wall films in the combustion chamber is a significant source of particulate formation in GDI engines. Particularly the wall surface temperature and the temperature drop due to the interaction with liquid fuel spray were identified as important parameters influencing the spray-wall interaction [1]. In order to quantify this temperature drop at combustion chamber surfaces, surface temperature measurements on the piston of a single-cylinder engine were conducted. Therefore, eight fast-response thermocouples were embedded 0.3 μm beneath the piston surface and the signals were transmitted from the moving piston to the data acquisition system via telemetry.

Due to the principle of direct injection, which is applied in modern homogeneously operated gasoline engines, there are various operation points with significant particulate emissions. The spray droplets contact the piston surface during the warm-up and early injections, in particular. The fuel wall films and the resulting delayed evaporation of the liquid fuel is one of the main sources of soot particles. It is therefore necessary to carry out investigations into the formation of wall film. The influence of the spray impact angle is of special interest, as this is a major difference between engines with side-mounted injectors and centrally positioned injectors. This paper describes an infrared thermography-based method, which we used to carry out a systematic study of fuel deposits on the walls of the combustion chamber. The boundary conditions of the test section were close to those of real GDI engines operated with homogeneous charge.

A pilot-main injection strategy is investigated for a part-load operating point in a single cylinder optical Diesel engine. As the energizing dwell between the pilot and main injections decreases below 200 μs, combustion noise reaches a minimum and a reduction of 3 dB is possible. This decrease in combustion noise is achieved without increased pollutant emissions. Injection schedules employed in the engine are analyzed with an injection analyzer to provide injection rates for each dwell tested. Two distinct injection events are observed even at the shortest dwell tested; rate shaping of the main injection occurs as the dwell is adjusted. High-speed elastic scattering imaging of liquid fuel is performed in the engine to examine initial liquid penetration rates.

Cost reduction of engine management systems (EMS) for two-wheeler applications is the key to utilize their potentials compared to carburetor bikes regarding emissions, fuel economy and system robustness. In order to reduce the costs of a system with port fuel injection (PFI) Bosch is developing an EMS without a manifold air pressure (MAP) sensor. The pressure sensor is usually used to compensate for different influences on the air mass, which cannot be detected via the throttle position sensor (TPS) and mean engine speed. Such influences are different leakage rates of the throttle body and changing ambient conditions like air pressure. Bosch has shown in the past that a virtual sensor relying on model based evaluation of engine speed can be used for a detection of leakage air mass in idling to improve the pre-control of the air-fuel ratio. This provides a functionality which so far was only possible with an intake pressure sensor.

The prime factor which influences noise and vibrations of electro-mechanical drives is wear at the components. This paper discusses the numerical methods developed for abrasion, vibration calculations and the coupling between wear and Noise Vibration and Harshness (NVH) models of the drive unit. The vibration domain model, initially, focuses on the calculations of mechanical excitations at the gear shafts which are generated via a nonlinear dynamic model. Furthermore, the bearings are studied for the influences on their stiffness and eventually their impact on the harmonics of the drivetrain. Later, free and forced vibrations of the complete drivetrain are simulated via a steady-state dynamic model. Consequently, the paper concentrates on the abrasion calculations at the gears. Wear is a complex process and understanding it is essential for determining the vibro-acoustics characteristics.

Acoustics and vibrations are amongst the foremost indicators in perceiving the quality of drive units. Analyzing these factors is vital for improve the performances of electro-mechanical systems. This paper deals with the study of vibro-acoustic behavior concerning the drivetrain components using system modeling and Finite Element calculations. A generic simulation methodology within system modeling is proposed enabling the vibro-acoustic simulation of electro-mechanical drivetrains. Excitations for these systems mostly arise from the electric motor and mechanical gears. The paper initially depicts the system model for gear whining considering the associated nonlinearities of the mesh. The results obtained from the gear mesh submodel, together with the excitations resulting from the motor, aid in the comprehension of the forces at the bearings and of the vibrations at the housings.

In order to optimize spray layouts of commonly used high-pressure injectors for gasoline direct injection (GDI) engines featuring multi-hole valve seats, a detailed understanding of the cause-effect relation between inner spray hole geometries and inner flow conditions, initializing the process of internal mixture formation, is needed. Therefore, a novel measurement setup, capable of determining spray hole individual mass flow rates, is introduced and discussed. To prove its feasibility, a 2-hole configuration is chosen. The injected fuel quantities are separated mechanically and guided to separate pressure tight measurement chambers. Each measurement chamber allows for time resolved mass flow rate measurements based on the HDA measurement principle (German: “Hydraulisches Druck-Anstiegsverfahren”).

The fuel-independent particulate emissions of a direct injection gasoline engine were investigated. This was done by running the engine with reference gasoline at four different loads and then switching to hydrogen or methane port fuel operation and comparing the resulting particulate emissions and their size distribution. Differences in the combustion characteristics of hydrogen and gasoline were accounted for by diluting the inlet air with nitrogen and matching the pressure or heat release traces to those of gasoline operation. Methane operation is expected to generate particulate emissions lower by several orders of magnitude compared to gasoline and hydrogen does not contribute to carbon soot formation because of the lack of carbon atoms in the molecule. Thus, any remaining particulate emissions at hydrogen gas operation must arise from non fuel related sources, e.g. from lubrication oil, metal abrasion or inlet air.

This paper presents the development of a novel direct coil cooling approach which can enable high performance for electric traction motor, and in further significantly reduce motor losses. The proposed approach focuses on bypassing critical thermal resistances in motor by cooling coils directly in stator slots with oil flow. Firstly, the basic configuration and features are shown: sealed stator slots to air gap, pressure reservoirs on both side of the slots and slot channels for oil flow. The key to enhance thermal performance of the motor here is based on introducing fluid guiding structure in the slot channels. Next, heat transfer in the channel with guiding structure is investigated by CFD and compared with bare slot channel without guiding structure. For studying the effectiveness of proposed cooling concept, numerical analysis is conducted to compare it with HEV favored oil impingement cooling.

General Motors has developed an all-new Ecotec 1.5 L range extender engine for use in the 2016 next generation Voltec propulsion system. This engine is part of a new Ecotec family of small displacement gasoline engines introduced in the 2015 model year. Major enhancements over the range extender engine in the current generation Voltec propulsion system include the adoption of direct injection (DI), cooled external exhaust gas recirculation (EGR), and a high 12.5:1 geometric compression ratio (CR). Additional enhancements include the adoption of high-authority phasers on both the intake and exhaust camshafts, and an integrated exhaust manifold (IEM). The combination of DI with cooled EGR has enabled significant thermal efficiency gains over the 1.4 L range extender engine in the current generation Voltec propulsion system at high engine loads.

The introduction of CO2-reduction technologies like Start-Stop or the Hybrid-Powertrain and the future emissions regulations require a detailed optimization of the engine start-up. The combustion concept development as well as the calibration of the ECU makes it necessary to carry out an explicit thermodynamic analysis of the combustion process during the start-up. As of today, the well-known thermodynamic analysis using in-cylinder pressure traces at stationary condition is transmitted to the highly dynamic engine start-up. Due to this approximation the current models for calculation of the transient wall heat fluxes by Woschni, Hohenberg and Bargende do not lead to desired results. But with a fraction of approximately 40 % of the burnt fuel energy, the wall heat is very important for the calculation of energy balance and for the combustion process analysis during start-up.