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The Energy Finite Element Analysis(EFEA) is a recent development for high frequency vibro-acoustic analysis, and constitutes an evolution in the area of high frequency computations. The EFEA is a wave based approach, while the SEA is a modal based approach. In this paper the similarities in the theoretical development of the two methods are outlined. The main scope of this paper is to establish the validity of the EFEA by analyzing several complex structural-acoustic systems. The EFEA solutions are compared successfully to SEA results and to solutions obtained from extremely dense conventional FEA models.

An experimental study is performed for homogeneous charge compression ignition (HCCI) combustion focusing on late phasing conditions with high cyclic variability (CV) approaching misfire. High CV limits the feasible operating range and the objective is to understand and quantify the dominating effects of the CV in order to enable controls for widening the operating range of HCCI. A combustion analysis method is developed for explaining the dynamic coupling in sequences of combustion cycles where important variables are residual gas temperature, combustion efficiency, heat release during re-compression, and unburned fuel mass. The results show that the unburned fuel mass carries over to the re-compression and to the next cycle creating a coupling between cycles, in addition to the well known temperature coupling, that is essential for understanding and predicting the HCCI behavior at lean conditions with high CV.

Digital human models (DHM) are now widely used to assess worker tasks as part of manufacturing simulation. With current DHM software, the simulation engineer or ergonomist usually makes a manual estimate of the likely worker standing location with respect to the work task. In a small number of cases, the worker standing location is determined through physical testing with one or a few workers. Motion capture technology is sometimes used to aid in quantitative analysis of the resulting posture. Previous research has demonstrated the sensitivity of work task assessment using DHM to the accuracy of the posture prediction. This paper expands on that work by demonstrating the need for a method and model to accurately predict worker standing location. The effect of standing location on work task posture and the resulting assessment is documented through three case studies using the Siemens Jack DHM software.

Developing a complete understanding of the structure and behavior of the near-wall region (NWR) in reciprocating, internal combustion (IC) engines and of its interaction with the core flow is needed to support the implementation of advanced combustion and engine operation strategies, as well as predictive computational models. The NWR in IC engines is fundamentally different from the canonical steady-state turbulent boundary layers (BL), whose structure, similarity and dynamics have been thoroughly documented in the technical literature. Motivated by this need, this paper presents results from the analysis of two-component velocity data measured with particle image velocimetry near the head of a single-cylinder, optical engine. The interaction between the NWR and the core flow was quantified via statistical moments and two-point velocity correlations, determined at multiple distances from the wall and piston positions.

Naturally aspirated HCCI operation is typically limited to medium load operation (∼ 5 bar net IMEP) by excessive pressure rise rate. Boosting can provide the means to extend the HCCI range to higher loads. Recently, it has been shown that HCCI can achieve loads of up to 16.3 bar of gross IMEP by boosting the intake pressure to more than 3 bar, using externally driven compressors. However, investigating HCCI performance over the entire speed-load range with real turbocharger systems still remains an open topic for research. A 1 - D simulation of a 4 - cylinder 2.0 liter engine model operated in HCCI mode was used to match it with off-the-shelf turbocharger systems. The engine and turbocharger system was simulated to identify maximum load limits over a range of engine speeds. Low exhaust enthalpy due to the low temperatures that are characteristic of HCCI combustion caused increased back-pressure and high pumping losses and demanded the use of a small and more efficient turbocharger.

Plenoptic particle tracking velocimetry (PTV) shows great potential for three-dimensional, three-component (3D3C) flow measurement with a simple single-camera setup. It is therefore especially promising for applications in systems with limited optical access, such as internal combustion engines. The 3D visualization of a plenoptic imaging system is achieved by inserting a micro-lens array directly anterior to the camera sensor. The depth is calculated from reconstruction of the resulting multi-angle view sub-images. With the present study, we demonstrate the application of a plenoptic system for 3D3C PTV measurement of engine-like air flow in a steady-state engine flow bench. This system consists of a plenoptic camera and a dual-cavity pulsed laser. The accuracy of the plenoptic PTV system was assessed using a dot target moved by a known displacement between two PTV frames.

This paper provides insight into the tradeoffs between exhaust energy recovery and increased pumping losses from the flow restriction of the electric turbo-generator (eTG) assessed using thermodynamic principles and with a detailed GT-Power engine model. The GT-Power engine model with a positive displacement expander model was used to predict the influence of back pressure on in-cylinder residuals and combustion. The eTG is assessed for two boosting arrangements: a conventional turbocharger (TC) and an electrically assisted variable speed (EAVS) supercharger (SC). Both a low pressure (post-turbine) and high pressure (pre-turbine) eTG are considered for the turbocharged configuration. The reduction in fuel consumption (FC) possible over various drive cycles is estimated based on the steady-state efficiency of frequently visited operating points assuming all recovered energy can be reused at an engine efficiency of 30% with 10% losses in the electrical path.

In-cylinder fluid velocity is measured in an optically accessible, fired HSDI engine at idle. The velocity field is also calculated, including the full induction stroke, using multi-dimensional fluid dynamics and combustion simulation models. A detailed comparison between the measured and calculated velocities is performed to validate the computed results and to gain a physical understanding of the flow evolution. Motored measurements are also presented, to clarify the effects of the fuel injection process and combustion on the velocity field evolution. The calculated mean in-cylinder angular momentum (swirl ratio) and mean flow structures prior to injection agree well with the measurements. Modification of the mean flow by fuel injection and combustion is also well captured.

The role of automotive electronics in light duty vehicles is continuing to expand rapidly. In this paper an overview of a 1986 Delphi forecast of major trends is presented. Trends discussed include electronics as a fraction of vehicle and component cost and projections of basic vehicle features supported by electronic technology. In addition, basic trends in diagnostics and multiplexing are presented. Several issues in support of automotive electronics are discussed, including the systems approach to vehicle engineering, the importance of developing a proper market strategy, and the continued major role of energy economics. The Delphi forecasting technique and its governing concepts are reviewed as a method to predict the future of automotive technology.

Exhaust gas recirculation (EGR) coolers are used on diesel engines to reduce peak in-cylinder flame temperatures, leading to less NOx formation during the combustion process. There is an ongoing concern with soot and hydrocarbon fouling inside the cold surface of the cooler. The fouling layer reduces the heat transfer efficiency and causes pressure drop to increase across the cooler. A number of experimental studies have demonstrated that the fouling layer tends to asymptotically approach a critical height, after which the layer growth ceases. One potential explanation for this behavior is the removal mechanism derived by the shear force applied on the soot and hydrocarbon deposit surface. As the deposit layer thickens, shear force applied on the fouling surface increases due to the flow velocity growth. When a critical shear force is applied, deposit particles start to get removed.

The object of this research was to learn more about the effects of mixture motion upon ignition in spark ignited piston engines, and to determine how variations in mixture velocity alter the combustion process. To provide effective means for producing and measuring the mixture velocity, all tests were made in a constant volume bomb, using mixtures of propane and air. The effects of mixture motion on the lean spark ignition limit, rate of pressure rise, and burning time were determined for mixture ratios ranging from stoichiometric to the lean limit. The mixture pressures corresponded to those in Otto cycle engines at the time of spark occurrence. The results reveal that a mixture velocity of 50 fps, relative to the spark plug, requires an enrichment of 17% with respect to the stagnant lean limit. Increases in mixture velocity were found to greatly increase the rate of pressure rise during combustion. This effect was more pronounced for lean mixtures than for stoichiometric mixtures.

A cylindrical combustion bomb with dynamic charging system and electro-hydraulic sampling valve is used to study the effects of turbulence on hydrocarbon (HC) emissions from a quench layer and from artificial crevices. The turbulence level is varied by changing the delay time between induction of combustible charge and ignition. Propane-air mixtures were studied over an initial pressure range of 150 to 500 kPa and equivalence ratios of 0.7 to 1.4. Sampling valve experiments show that quench-layer fuel hydrocarbons are extensively oxidized within 5 ms of flame arrival under laminar conditions and that turbulence further reduces the already low level. Upper limit estimates of the residual wall layer HC concentration show that residual quench layer hydrocarbons are only a small fraction of the exhaust HC emission.

Possible mechanisms for smoke formation in the diesel engine are discussed. Emphasis is placed on the effects of some engine and fuel factors on carbon formation during the course of combustion, including cetane number, fuel volatility, air charge temperature, and after-injection. The tests were made with a single-cylinder, open chamber research engine, with three fuels, covering a wide range of inlet air temperatures and pressures. There is evidence that smoke intensity increased with increase in the cetaine number of the fuels with inlet air temperatures near atmospheric. Increase in the air charge temperature caused an increase in smoke intensity for volatile fuels and had an opposite effect on less volatile fuels for the open chamber engine used. The smoke intensity was found to increase dramatically with after-injection, with all other parameters kept constant. The concept that flame cooling is the main cause for smoke formation is examined.

Present-day implementations of premixed compression ignition low temperature (PCI) combustion in diesel engines use higher levels of exhaust gas recirculation (EGR) than conventional diesel combustion. Two common devices that can be used to achieve high levels of EGR are an intake throttle and a variable geometry turbocharger (VGT). Because the two techniques affect the engine air system in different ways, local combustion conditions differ between the two in spite of, in some cases, having similar burn patterns in the form of heat release. The following study has developed from this and other observations; observations which necessitate a deeper understanding of emissions formation within the PCI combustion regime. This paper explains, through the use of fundamental phenomenological observations, differences in ignition delay and emission indices of particulate matter (EI-PM) and nitric oxides (EI-NOx) from PCI combustion attained via the two different techniques to flow EGR.

Privacy has been a rising concern. The European Union has established a privacy standard called General Data Protection Regulation (GDPR) in May 2018. Furthermore, the Facebook-Cambridge Analytica data incident made headlines in March 2018. Data collection from vehicles by OEM platforms is increasingly popular and may offer OEMs new business models but it comes with the risk of privacy leakages. Vehicular sensor data shared with third-parties can lead to misuse of the requested data for other purposes than stated/intended. There exists a relevant regulation document introduced by the Alliance of Automobile Manufacturers (“Auto Alliance”), which classifies the vehicular sensors used for data collection as covered and non-sensitive parameters.

A comprehensive formulation is presented for the dynamics of a rotating flexible crankshaft coupled with the dynamics of an engine block through a finite difference elastohydrodynamic main bearing lubrication algorithm. The coupling is based on detailed equilibrium conditions at the bearings. The component mode synthesis is employed for modeling the crankshaft and block dynamic behavior. A specialized algorithm for coupling the rigid and flexible body dynamics of the crankshaft within the framework of the component mode synthesis has been developed. A finite difference lubrication algorithm is used for computing the oil film elastohydrodynamic characteristics. A computationally accurate and efficient mapping algorithm has been developed for transferring information between a high - density computational grid for the elastohydrodynamic bearing solver and a low - density structural grid utilized in computing the crankshaft and block structural dynamic response.

Premixed compression ignition low-temperature diesel combustion (PCI) can simultaneously reduce particulate matter (PM) and oxides of nitrogen (NOx). Carbon monoxide (CO) and total hydrocarbon (THC) emissions increase relative to conventional diesel combustion, however, which may necessitate the use of a diesel oxidation catalyst (DOC). For a better understanding of conventional and PCI combustion, and the operation of a platinum-based production DOC, engine-out and DOC-out exhaust hydrocarbons are speciated using gas chromatography. As combustion mode is changed from lean conventional to lean PCI to rich PCI, engine-out CO and THC emissions increase significantly. The relative contributions of individual species also change; increasing methane/THC, acetylene/THC and CO/THC ratios indicate a richer combustion zone and a reduction in engine-out hydrocarbon incremental reactivity.

A two phase, global combustion model has been developed for quiescent chamber, direct injection diesel engines. The first stage of the model is essentially a spark ignition engine flame spread model which has been adapted to account for fuel injection effects. During this stage of the combustion process, ignition and subsequent flame spread/heat release are confined to a mixing layer which has formed on the injected jet periphery during the ignition delay period. Fuel consumption rate is dictated by mixing layer dynamics, laminar flame speed, large scale turbulence intensity, and local jet penetration rate. The second stage of the model is also a time scale approach which is explicitly controlled by the global mixing rate. Fuel-air preparation occurs on a large-scale level throughout this phase of the combustion process with each mixed fuel parcel eventually burning at a characteristic time scale as dictated by the global mixing rate.

This presentation is an assessment of the turbulence-stress scale-similarity in an IC engine, which is used for modeling subgrid dissipation in LES. Residual stresses and Leonard stresses were computed after applying progressively smaller spatial filters to measured and simulated velocity distributions. The velocity was measured in the TCC-II engine using planar and stereo PIV taken in three different planes and with three different spatial resolutions, thus yielding two and three velocity components, respectively. Comparisons are made between the stresses computed from the measured velocity and stress computed from the LES resolved-scale velocity from an LES simulation. The results present the degree of similarity between the residual stresses and the Leonard stresses at adjacent scales. The specified filters are systematically reduced in size to the resolution limits of the measurements and simulation.

Originally written in 1976 and previously revised in 1983, The Maintenance Council (TMC) Recommended Practice RP-404B is intended to enhance the safety of motor carrier employees by providing guidance regarding the purchase and use of access systems on heavy truck and truck tractors. Compliance with the recommended practice is intended to permit anyone entering or exiting a cab to have three limbs in contact with the truck or truck-tractor at arty time. The scope of the recommended practice covers access systems to the cab and rear of cab areas of all types of heavy trucks and truck tractors, in contrast to Bureau of Motor Carrier Safety (BMCS) regulations which applies only to Cab Over Engine (COE) tractors. The Maintenance Council recommended practice also varies from the BMCS requirements in that it remains a design oriented document.