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Global emission legislations for diesel engines are becoming increasingly stringent. While the exhaust gas composition requirements for prior iterations of emission legislation could be met with improvements in the engine's combustion process, the next issue of European, North American and Japanese emission limits greater than 2005 will require more rigorous measures, mainly employment of exhaust gas aftertreatment systems. As a result, many American diesel OEMs are considering NOx adsorbers as a means to achieve 2007+ emission standards. Since the efficacy of a NOx adsorber over its lifetime is significantly affected by sulfur (“sulfur poisoning”), forthcoming reductions in diesel fuel sulfur (down to 15 ppm), have raised industry concerns regarding compatibility and possible poisoning effects of sulfur from the lubricant.

Sulfur poisoning from engine fuel and lube is one of the most recognizable degradation mechanisms of a NOx adsorber catalyst system for diesel emission reduction. Even with the availability of 15 ppm sulfur diesel fuel, NOx adsorber will be deactivated without an effective sulfur management. Two general pathways are currently being explored for sulfur management: (1) the use of a disposable SOx trap that can be replaced or rejuvenated offline periodically, and (2) the use of diesel fuel injection in the exhaust and high temperature de-sulfation approach to remove the sulfur poisons to recover the NOx trapping efficiency. The major concern of the de-sulfation process is the many prolonged high temperature rich cycles that catalyst will encounter during its useful life. It is shown that NOx adsorber catalyst suffers some loss of its trapping capacity upon high temperature lean-rich exposure.

Plug flow reactors, simulating engine exhaust gas, are widely used in emissions control research to gain insight into the reaction mechanisms and engineering aspects that controls activity, selectivity, and durability of catalyst components. The choice of relevant hydrocarbon (HC) species is one of the most challenging factor in such laboratory studies, given the variety of compositions that can be encountered in different application scenarios. Furthermore, this challenge is amplified by the experimental difficulties related to introducing heavier and multi-component HCs and analyzing the reaction products.

A technique for rapid in situ measurement of the fuel dilution of oil in a diesel engine is presented. Fuel dilution can occur when advanced in-cylinder fuel injection techniques are employed for the purpose of producing rich exhaust for lean NOx trap catalyst regeneration. Laser-induced fluorescence (LIF) spectroscopy is used to monitor the oil in a Mercedes 1.7-liter engine operated on a dynamometer platform. A fluorescent dye suitable for use in diesel fuel and oil systems is added to the engine fuel. The LIF spectra are monitored to detect the growth of the dye signal relative to the background oil fluorescence; fuel mass concentration is quantified based on a known sample set. The technique was implemented with fiber optic probes which can be inserted at various points in the engine oil system. A low cost 532-nm laser diode was used for excitation.

Biodiesel is a promising alternative to traditional diesel fuel due to its similar combustion properties to diesel and lower carbon emissions on a well-to-wheel basis. However, combusting biodiesel still generates hydrocarbon (HC), CO, NOx and particulate matter (PM) emissions, similar to those from traditional diesel fuel usage. Therefore, aftertreatment systems will be required to reduce these emissions to meet increasingly stringent emission regulations to minimize the impact to the environment. Diesel oxidation catalysts (DOC) are widely used in modern aftertreatment systems to convert unburned HC and CO, to partially convert NO to NO2 to enhance downstream selective catalytic reaction (SCR) catalyst efficiency via fast SCR and to periodically clean-up DPF via controlled soot oxidation. In this work, we focus on the performance difference between biodiesel and diesel over a commercial DOC catalyst to identify the knowledge gap during the transition from diesel fuel to biodiesel.

Cooled EGR continues to be a key technology to meet emission regulations, with EGR coolers performing a critical role in the EGR system. Designing EGR coolers that reliably manage thermal loads is a challenge with thermal fatigue being a top concern. The ability to estimate EGR cooler thermal fatigue life early in the product design and validation cycle allows for robust designs that meet engine component reliability requirements and customer expectations. This paper describes a process to create an EGR cooler thermal fatigue life model. Components which make up the EGR cooler have differing thermal responses, consequently conjugate transient CFD must be used to accurately model metal temperatures during heating and cooling cycles. Those metal temperatures are then imported into FEA software for structural analysis. Results from both the CFD and FEA are then used in a simplified numerical model to estimate the virtual strain of the EGR cooler.

Sulfur containing species as well as other polar molecules provide lubricity and thermal stability to diesel fuels. During the refining process to produce low and ultra-low sulfur diesel fuels, these components are removed. As a result, fuel additives such as lubricity agents and antioxidant may be added to protect fuel stability and prevent fuel pump wear. Some lubricity additives, such as dimer acids, resulted in fuel filter plugging. The plugging mechanism was related to the capability of aliphatic acids to form agglomeration by interactions with the overbased detergents, delivered into the fuel as oil contaminants. Other sources of acids, derived from thermal degradation, can lead to the same problem. In this study, individual lubricant additives were mixed in the fuel to form single- and dual-component systems. Levels of compatibility and amounts of interaction products were evaluated for individual solutions.

Despite drastic reduction of sulfur content in diesel fuel in the recent years, especially with the introduction of Ultra-Low Sulfur Diesel (ULSD), sulfur poisoning remains one of the most significant factors impacting performance of various catalysts in diesel aftertreatment systems. This is because even with ULSD, cumulative exposure of a catalyst over its lifetime in a heavy-duty diesel system may amount to kilograms of sulfur. In this study, we have found that the impact of sulfur poisoning on the performance of various diesel oxidation catalysts (DOC) strongly depends on the catalyst's operation history. For example, exposing a DOC to limited amounts of freshly deposited sulfur in bench reactor testing was shown to have a substantial detrimental effect. On the other hand, several samples which returned from vehicle or test-cell aging with high sulfur loading, have shown no signs of poisoning.

Automotive timing gear trains, transmission gearboxes, and wind turbine gearboxes are some of the application examples known to use interference-fit to attach the gear to the rotating shaft. This paper discusses the interference-fit joint design and the finite element analysis to demonstrate the distortion. The mechanism of tooth profile distortion due to the interference-fit assembly in gear trains is discussed by demonstrating the before and after assembly gear profile measurements. An algorithm to calculate the profile slope deviation change is presented. The effectiveness of the computational algorithm to predict the distortion is demonstrated by comparing with measurements. Finally, steps to mitigate the interference assembly effects are discussed.

This paper presents an experimental setup and an equivalent FEM simulation methodology to accurately predict the response of Engine Control Module (ECM) assembly mounted on a commercial vehicle subjected to road vibrations. Comprehensive vibration study is carried out. It involved Modal characteristics determination followed by random vibration characterization of the ECM assembly. A hammer impact experiment is first performed in lab to estimate the natural frequencies and mode shapes of ECM assembly. Mounting conditions in test specimen are kept similar to the actual mounting settings on vehicle. Natural frequencies and mode shapes predicted from free vibration experiment are compared with finite element (FE) based modal analysis. The importance of capturing the assembly stiffness more accurately by incorporating pre-stress effects like bolt-pretension and gravity, is emphasized.

Effects of methyl ester biodiesel fuel blends on NOx emissions are studied experimentally and analytically. A precisely controlled single cylinder diesel engine experiment was conducted to determine the impact of a 20% blend of soy methyl ester biodiesel (B20) on NOx emissions. The data were then used to calibrate KIVA chemical kinetics models which were used to determine how the biodiesel blend affects NOx production during the combustion process. In addition, the impact on the engine control system of the lower specific energy content of biodiesel was determined. Both factors, combustion and controls, must be taken into account when determining the net NOx effect of biodiesel compared to conventional diesel fuel. Because the magnitude and even direction of NOx effect changes with engine load, the NOx effect associated with burning biodiesel blends over a duty cycle depends on the duty cycle average power and fuel cetane number.

Heat rejection, liner temperature, exhaust valve seat temperature, and head gasket temperature data were recorded during a full load torque sweep of a compression ignition engine when fueled by No. 2 diesel and an ethanol/diesel fuel blend containing 10% ethanol by volume. Heat balances were calculated for engine operation at various load-speed combinations. The results of this study indicated that a greater than expected volume of E-diesel was required to operate the compression ignition engine at the same torque-speed compared to No. 2 diesel. More E-diesel fuel was required due to lower brake thermal efficiencies for E-diesel. Other than exhaust seat temperatures, there were no appreciable differences in component temperatures measured throughout the engine or the results of the heat balances calculated for the No. 2 diesel and E-diesel fuels.

Dynamometer (dyno) durability testing plays a significant role in reliability and durability assessment of commercial engines. Frequently, durability test procedures are based on warranty history and corresponding component failure modes. Evolution of engine designs, operating conditions, electronic control features, and diagnostic limits have created challenges to historical-based testing approaches. A physics-based methodology, known as Load Matrix, is described to counteract these challenges. The technique, developed by AVL, is based on damage factor models for subsystem and component failure modes (e.g. fatigue, wear, degradation, deposits) and knowledge of customer duty cycles. By correlating dyno test to field conditions in quantifiable terms, such as customer equivalent miles, more effective and efficient durability test suites and test procedures can be utilized. To this end, application of Load Matrix to a heavy-duty diesel engine is presented.

This study is a continuation of previous work assessing the robustness of a Cummins XPI common rail injection system operating with gasoline-like fuel. All the hardware from the original study was retained except for the high pressure pump head and check valves which were replaced due to cavitation damage. An additional 400 hour NATO cycle was run on the refurbished fuel system to achieve a total exposure time of 800 hours and detect any other significant failure modes. As in the initial investigation, fuel system parameters including pressures, temperatures and flow rates were logged on a test bench to monitor performance over time. Fuel and lubricant samples were taken every 50 hours to assess fuel consistency, metallic wear, and interaction between fuel and oil. High fidelity driving torque and flow measurements were made to compare overall system performance when operating with both diesel and light distillate fuel.

A head gasket is a component that sits between the engine block/liner and cylinder head(s) in an internal combustion engine. Its purpose is to seal high pressure combustion gasses in the cylinders and to seal coolant and engine oil. It is the most critical sealing application in an engine. As a general practice, the load deflection(L/D) characteristic is generated by the gasket manufacturer for edge molded or composite gasket types. However, in the case of a solid-sheet metallic gasket, where the gasket is expected to undergo localized yielding to provide adequate conformance and sealing, usually supplier may not be able to provide the required L/D curve due to difficulties to experimentally separate the large loads and small displacements from the elastic loads and deflections of the experimental apparatus. In absence of L/D curve, the typical analysis approach is to model gasket as 3D continuum elements available in ansys by considering nonlinear material and frictional contacts.

This paper describes the methodology used to select an application-based fan that has optimum operating characteristics in terms of cooling air flow rate, fan power, and noise. The selected fan is then evaluated for structural strength. To evaluate different fans, complete rail coach under-hood simulations were carried out using steady-state 3D computational fluid dynamics (CFD) approach. These simulations considered an actual, highly non-uniform flow field. For each fan option, fan power, air flow rate, and surface acoustic power was evaluated. Pressure profiles on the fan blades were studied to assess the effect of non-uniform downstream air passage designs. Surface acoustic power was calculated using broadband noise source (BNS) model in ANSYS Fluent®. Surface pressure profiles over fan blades imported from 3D CFD were used in finite element analysis (FEA) in ANSYS. Analyses were carried out for blade linear and non-linear properties.

With the capability of avoiding failure in advance, failure prediction model is important not only to end users, but also to the service engineers in vehicle industry. This paper proposes an approach based on anomaly detection algorithms and telematic data to predict the failure of the engine air system with Turbo charger. Firstly, the relationship between air system and all obtained features are analyzed by both physical mechanism and data-wise. Then, the features including altitude, air temperature, engine output power, and charger pressure are selected as the input of the model, with the sampling interval of 1 minute. Based on the selected features, the healthy state for each vehicle is defined by the model as benchmark. Finally, the ‘Medium surface’ is determined for specific vehicle, which is a hyperplane with the medium points of the healthy state located at, to detect the minor weakness symptom (sub-health state).

Various 1D simulation tools (KULI & LMS Amesim) and 3D simulation tools (ANSYS FLUENT®) can be used to size and evaluate truck cooling system design. In this paper, ANSYS FLUENT is used to analyze and validate the design of medium duty truck cooling systems. LMS Amesim is used to verify the quality of heat exchanger input data. This paper discusses design and simulation of parent and derivative trucks. As a first step, the parent truck was modeled in FLUENT (using standard' k - ε model) with detailed fan and underhood geometry. The fan is modeled using Multiple Reference Frame (MRF) method. Detailed geometry of heat exchangers is skipped. The heat exchangers are represented by regular shape cell zones with porous medium and dual cell heat exchanger models to account for their contributions to the entire system in both flow and temperature distribution. Good agreement is observed between numerical and experimental engine out temperatures at different engine operating conditions.

Commercial automotive diesel engine service and repair, post a diagnostic trouble code trigger, relies on standard troubleshooting steps laid down to identify or narrow down to a faulty engine component. This manual process is cumbersome, time-taking, costly, often leading to incorrect part replacement and most importantly usually associated with significant downtime of the vehicle. Current study aims to address these issues using a novel in-house simulation-based approach developed using a Digital Twin of the engine which is capable of conducting in-mission troubleshooting with real world vehicle/engine data. This cost-effective and computationally efficient solution quickly provides the cause of the trouble code without having to wait for the vehicle to reach the service bay. The simulation is performed with a one-dimensional fluid dynamics, detailed thermodynamics and heat transfer-based diesel engine model utilizing the GT-POWER engine performance tool.

In the early years of antifreeze/coolants (1920s & 30s) glycerin saw some usage, but because of higher cost and weaker freeze point depression, it was not competitive with ethylene glycol. Glycerin is a by-product of the manufacture of biodiesel (fatty acid methyl esters) made by reacting natural vegetable or animal fats with methanol. Biodiesel fuel is becoming increasingly important and is expected to gain a large market share in the next several years. Regular diesel fuels blended with 2%, 5%, and 20% biodiesel are now commercially available. The large amount of glycerin generated from high volume usage of biodiesel fuel has resulted in this chemical becoming cost competitive with the glycols currently used in engine coolants. For this reason, and lower toxicity comparable to that of propylene glycol, glycerin deserves to be reconsidered as a base for antifreeze/coolant.