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A simulation framework with a validated system model capable of estimating fuel consumption is a valuable tool in analysis and design of the hybrid vehicles. In particular, the framework can be used for (1) benchmarking the fuel economy achievable from alternate hybrid powertrain technologies, (2) investigating sensitivity of fuel savings with respect to design parameters (for example, component sizing), and (3) evaluating the performance of various supervisory control algorithms for energy management. Presenter Chinmaya Patil, Eaton Corporation

An advanced exhaust aftertreatment system is characterized following end-of-life catalyst aging to meet final Tier 4 off-highway emission requirements. This system consists of a fuel dosing system, mixing elements, fuel reformer, lean NOx trap (LNT), diesel particulate filter (DPF), and a selective catalytic reduction (SCR) catalyst. The fuel reformer is used to generate hydrogen (H2) and carbon monoxide (CO) from injected diesel fuel. These reductants are used to regenerate and desulfate the LNT catalyst. NOx emissions are reduced using the combination of the LNT and SCR catalysts. During LNT regeneration, ammonia (NH3) is intentionally released from the LNT and stored on the downstream SCR catalyst to further reduce NOx that passed through the LNT catalyst. This paper addresses system durability as the catalysts were aged to 500 desulfation events using an off-highway diesel engine.

Diesel exhaust aftertreatment systems are required for meeting both EPA 2010 and final Tier 4 emission regulations. This paper addresses aftertreatment system performance of a fuel reformer, lean NOx trap (LNT) and selective catalytic reduction (SCR) system designed to meet the EPA 2010 emission standards for an on-highway heavy-duty vehicle. The aftertreatment system consists of a fuel dosing system, mixing elements, fuel reformer, LNT, diesel particulate filter (DPF), and SCR for meeting NOx and particulate emissions. System performance was characterized in an engine dynamometer test cell, using a development, 13L, heavy-duty engine. The catalyst performance was evaluated using degreened catalysts. Test results show that system performance met the EPA 2010 emission standards under a range of test conditions that were reflective of actual vehicle operation.

The identification of the dominant noise sources in diesel engines and the assessment of their contribution to far-field noise is a process that can involve both fired and motored testing. In the present work, the cross-spectral densities of signals from cylinder pressure transducers, accelerometers mounted on the engine surface, and microphones (in the near and far fields), were used to identify dominant noise sources and estimate the transfer paths from the various “inputs” (i.e., the cylinder pressures, the accelerometers and the near field microphones) to the far field microphones. The method is based on singular value decomposition of the input cross-spectral matrix to relate the input measurements to independent virtual sources. The frequencies at which a particular input is strongly affected by an independent source are highlighted, and with knowledge of transducer locations, inferences can be drawn as to possible noise source mechanisms.

Diesel Cylinder Deactivation (CDA) has been shown in previous work to increase exhaust temperatures, improve fuel efficiency, and reduce engine-out NOx for engine loads up to 3 bar BMEP. The purpose of this study is to determine whether or not the turbocharger needs to be altered when implementing CDA on a diesel engine. This study investigates the effect of CDA on exhaust temperature, fuel efficiency, and turbocharger performance in a 15L heavy-duty diesel engine under low-load (0-3 bar BMEP) steady-state operating conditions. Two calibration strategies were evaluated. First, a “stay-hot” thermal management strategy in which CDA was used to increase exhaust temperature and reduce fuel consumption. Next, a “get-hot” strategy where CDA and elevated idle speed was used to increase exhaust temperature and exhaust enthalpy for rapid aftertreatment warm-up.

Experimental measurements of tire tread band vibration have provided direct evidence that higher order structural-acoustic modes exist in tires, not just the well-known fundamental acoustical mode. These modes display both circumferential and radial pressure variations within the tire's air cavity. The theory governing these modes has thus been investigated. A brief recapitulation of the previously-presented coupled structural-acoustical model based on a tensioned string approach will be given, and then an improved tire-acoustical model with a ring-like shape will be introduced. In the latter model, the effects of flexural and circumferential stiffness are considered. This improved model accounts for propagating in-plane vibration in addition to the essentially structure-borne flexural wave and the essentially airborne longitudinal wave accounted for in the previous model. The longitudinal structure-borne wave “cuts on” at the tire's circumferential ring frequency.

Component sound quality is an important factor in the design of competitive diesel engines. One component noise that causes complaints is the gear rattle that originates in the front-of-engine gear train which drives the fuel pump and other accessories. The rattle is caused by repeated tooth impacts resulting from fluctuations in differential torsional acceleration of the driving gears. These impacts generate a broadband, impulsive noise that is often perceived as annoying. In most previous work, the overall sound quality of diesel engines has been considered without specifically focusing on predicting the perception of gear rattle. Gear rattle level has been quantified based on angular acceleration measurements, but those measurements can be difficult to perform. Here, the emphasis was on developing a metric based on subjective testing of the perception of gear rattle.

An experiment has been developed to investigate the ignition characteristics of ultra-lean premixed H2/air mixtures by a supersonic hot jet. The hot jet is generated by combustion of a stoichiometric mixture in a small prechamber. The apparatus adopted a dual-chamber design in which a small-volume (1% of the main chamber by volume) prechamber was installed within a large-volume main chamber. A small orifice (nozzle) connects the two chambers. Spark initiated combustion inside the prechamber causes a pressure rise and pushes the gases though the nozzle, resulting in a hot jet that would ignite the lean mixture in the main chamber. Simultaneous high-speed Schlieren photography and OH* Chemiluminescence were applied to visualize the jet penetration and the ignition processes inside the main chamber. Hot Wire Pyrometry (HWP) was used to measure temperature distribution of the transient hot jet.

The following computational study examines the structure of sonic hydrogen jets using inlet conditions similar to those encountered in direct-injection hydrogen engines. Cases utilizing the same mass and momentum flux while varying exit-to-chamber pressure ratios have been investigated in a constant-volume computational domain. Furthermore, subsonic versus sonic structures have been compared using both hydrogen and ethylene fuel jets. Finally, the accuracy of scaling arguments to characterize an underexpanded jet by a subsonic “equivalent jet” has been assessed. It is shown that far downstream of the expansion region, the overall jet structure conforms to expectations for self-similarity in the far-field of subsonic jets. In the near-field, variations in fuel inlet-to-chamber pressure ratios are shown to influence the mixing properties of sonic hydrogen jets. In general, higher pressure ratios result in longer shock barrel length, though numerical resolution requirements increase.

Sintered valve guides are increasingly used in various engine applications due to their superior durability and cost. Typical valve guide materials are low alloyed materials of the type Fe-Cu-C. More severe applications may require higher alloying content. One such application is EGR where the exhaust temperatures are much higher as compared to the conventional automotive valve guide. A new material was developed to work in this harsh environment. The object of this paper is to report development of this material including material properties and durability test results.

An LNT + SCR diesel aftertreatment system was developed in order to meet the 2010 US HD EPA on-road, and tier 4 US HD EPA off-road emission standards. This system consists of a fuel reformer (REF), lean NOx trap (LNT), catalyzed diesel particulate filter (DPF), and selective catalytic reduction (SCR) catalyst arranged in series to reduce tailpipe nitrogen oxides (NOx) and particulate matter (PM). This system utilizes a REF to produce hydrogen (H2), carbon monoxide (CO) and heat to regenerate the LNT, desulfate the LNT, and actively regenerate the DPF. The NOx stored on the LNT is reduced by the H2 and CO generated in the REF converting it to nitrogen (N2) and ammonia (NH3). NH3, which is normally an undesired byproduct of LNT regeneration, is stored in the downstream SCR which is utilized to further reduce NOx that passes through the LNT. Engine exhaust PM is filtered and trapped by the DPF reducing the tailpipe PM emissions.

The paper covers the NOx performance evaluation of an LNT + SCR system designed to meet the 2010 on-highway heavy-duty (HD) US EPA emission standards. The system combines a fuel reformer catalyst (REF), lean NOx trap (LNT), diesel particulate filter (DPF), and selective catalytic reduction (SCR) in series, to reduce engine-out NOx and PM. System NOx reduction performance was verified in an engine dynamometer test cell, using a 2007 7.6L medium-duty engine. System NOx performance was characterized using fresh LNT and SCR along with hydrothermal aged LNT and fresh SCR. Test results show levels consistent with EPA 2010 limits under various test conditions. Catalysts performance was characterized at eight steady engine-operating conditions (A100, B50, B75, A75, B100, C100, C75, C50, across a 13-mode Supplemental Emission Test (SET), and an on-highway Heavy Duty Federal Test Procedure (HD-FTP).

Conventional hydraulic steering systems keep improving performance and driving comfort by introducing advanced features via mechanical design. The ever increasing mechanical complexity requires the advanced modeling and simulation technology to mitigate the risks in the early stage of the development process. In this paper, we focus on advanced modeling tools environment with an example of a load sensing hydraulic steering system. The complete system architecture is presented. Analytical equations are developed for a priority valve and a steering control unit as the foundation of modeling. The full version of hydraulic steering system model is developed in Dymola platform. In order to capture interaction between steering and vehicle, the co-simulation platform between the hydraulic steering system and vehicle dynamics is established by integrating Dymola, Carsim and Simulink.

Global environmental and economic concerns regarding increasing fuel consumption and greenhouse gas emission are driving changes to legislative regulations and consumer demand. As regulations become more stringent, advanced engine technologies must be developed and implemented to realize desired benefits. Discrete variable valve lift technology is a targeted means to achieve improved fuel economy in gasoline engines. By limiting intake air flow with an engine valve, as opposed to standard throttling, road-load pumping losses are reduced resulting in improved fuel economy. This paper focuses on the design and development of a switching roller finger follower system which enables two mode discrete variable valve lift on end pivot roller finger follower valvetrains. The system configuration presented includes a four-cylinder passenger car engine with an electro-hydraulic oil control valve, dual feed hydraulic lash adjuster, and switching roller finger follower.

This paper presents a simulation model for the analysis of internal gear ring pumps. The model follows a multi domain simulation approach comprising sub-models for parametric geometry generation, fluid dynamic simulation, numerical calculation of characteristic geometry data and CAD/FEM integration. The sub-models are interacting in different domains and relevant design and simulation parameters are accessible in a central, easy to handle graphical user interface. The potentials of the described tool are represented by simulation results for both steady state and transient pump operating conditions and by their correlation with measured data. Although the presented approach is suitable to all applications of gear ring pumps, a particular focus is given to hydraulic actuation systems used in automotive drivetrain applications.

Excessive vibration and poor controllability occur in many mobile fluid power applications, with negative consequences as concerns operators' health and comfort as well as machine safety and productivity. This paper addresses the problem of reducing oscillations in fluid power machines presenting a novel control technique of general applicability. Strong nonlinearities of hydraulic systems and the unpredictable operating conditions of the specific application (e.g. uneven ground, varying loads, etc.) are the main challenges to the development of satisfactory general vibration damping methods. The state of the art methods are typically designed as a function of the specific application, and in many cases they introduce energy dissipation and/or system slowdown. This paper contributes to this research by introducing an energy efficient active damping method based on feedback signals from pressure sensors mounted on the flow control valve block.

Supercharger gear whine noise has been a NVH concern for many years, especially around idle rpm. The engine masking noise is very low at idle and the supercharger is sensitive to transmitted gear whine noise from the timing gears. The low loads and desire to use spur gears for ease in timing the rotors have caused the need to make very accurate profiles for minimizing gear whine noise. Over the past several years there has been an effort to better understand gear whine noise source and transmission path. Based on understanding the shaft bending mode frequencies and better gear design optimization tools, the gear design was modified to increase the number of teeth in order to move out of the frequency range of the shaft bending modes at idle speed and to lower the transmission error of the gear design through optimization using the RMC (Run Many Cases) software from the OSU gear laboratory.

The four-microphone standing wave tube system has proven useful for measuring the absorption and transmission loss of various fibrous and non-fibrous absorbers. The system is fast, repeatable, accurate and compact. This paper discusses the advantages of the four-microphone system for measuring the transmission loss in lateral-flow absorber systems. The original four-microphone round impedance tube system and the migration to a four-microphone square tube system are discussed. The four-microphone square tube system allows effective study of filled and partially filled cavities.

Notched spoilers may be used to suppress flow-induced cavity resonance in vehicles with open sunroofs or side windows. The notches are believed to generate streamwise vortices that break down the structure of the leading edge cross-stream vortices predominantly responsible for the cavity excitation. The objectives of the present study were to gain a better understanding of the buffeting suppression mechanisms associated with notched spoilers, and to gather data for computational model verification. To this end, experiments were performed to characterize the surface pressure field downstream of straight and notched spoilers mounted on a rigid wall to observe the effects of the notches on the static and dynamic wall pressure. Detailed flow velocity measurements were made using hot-wire anemometry. The results indicated that the presence of notches on the spoiler reduces drag, and thus tends to move the flow reattachment location closer to the spoiler.

ADVISOR is a flexible drivetrain analysis tool, developed in MATLAB/Simulink® to compare fuel economy and emissions performance between different drivetrain configurations. This paper reports a couple of numerical issues with application of ADVISOR 2002 to commercial vehicles with traditional powertrain systems. One instance is when ADVISOR model is set up to simulate running a heavy-duty (HD) truck with an automated manual transmission (AMT) on a demanding pickup-delivery duty cycle. The other is highlighted during an analysis of a medium-duty (MD) truck with an automatic transmission (AT) where wide-open throttle, i.e., fast acceleration is requested. These two cases have shown different numerical difficulties by using ADVISOR 2002. Based on studying the details of the models, solutions to these numerical issues are developed. The simulation results will demonstrate the effectiveness of these solutions.