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A Study of PGM-Free Oxidation Catalyst YMnO3 for Diesel Exhaust Aftertreatment

2012-06-18
Manganese oxides show high catalytic activity for CO and HC oxidation without including platinum group metals (PGM). However, there are issues with both thermal stability and resistance to sulfur poisoning. We have studied perovskite-type YMnO3 (YMO) with the aim of simultaneously achieving both activity and durability. This paper describes the oxidation activity of PGM-free Ag/i-YMO, which is silver supported on improved-YMO (i-YMO). The Ag/i-YMO was obtained by the following two methods. First, Mn4+ ratio and specific surface area of YMO were increased by optimizing composition and preparation method. Second, the optimum amount of silver was supported on i-YMO. In model gas tests and engine bench tests, the Ag/i-YMO catalyst showed the same level of activity as that of the conventional Pt/?-Al2O3 (Pt = 3.0 g/L). In addition, there was no degradation with respect to either heat treatment (700°C, 90 h, air) or sulfur treatment (600°C to 200°C, total 60 h, 30 ppm SO2).
Technical Paper

Measurement of Diesel Spray Impingement and Fuel Film Characteristics Using Refractive Index Matching Method

2007-04-16
2007-01-0485
The fuel film thickness resulting from diesel fuel spray impingement was measured in a chamber at conditions representative of early injection timings used for low temperature diesel combustion. The adhered fuel volume and the radial distribution of the film thickness are presented. Fuel was injected normal to the impingement surface at ambient temperatures of 353 K, 426 K and 500 K, with densities of 10 kg/m3 and 25 kg/m3. Two injectors, with nozzle diameters of 100 μm and 120 μm, were investigated. The results show that the fuel film volume was strongly affected by the ambient temperature, but was minimally affected by the ambient density. The peak fuel film thickness and the film radius were found to increase with decreased temperature. The fuel film was found to be circular in shape, with an inner region of nearly constant thickness. The major difference observed with temperature was a decrease in the radial extent of the film.
Technical Paper

Management System for Continuously Variable Valve Lift Gasoline Engine

2007-04-16
2007-01-1200
A continuously variable valve lift gasoline engine can improve fuel consumption by reducing pumping loss and increase maximum torque by optimizing valve lift and cam phase according to engine speed. In this research, a new control system to simultaneously ensure good driveability and low emissions was developed for this low fuel consumption, high power engine. New suction air management through a master-slave control made it possible to achieve low fuel consumption and good driveability. To regulate the idle speed, a new controller featuring a two-degree-of-freedom sliding-mode algorithm with cooperative control was designed. This controller can improve the stability of idle speed and achieve the idle operation with a lower engine speed. To reduce emissions during cold start condition, an ignition timing control was developed that combine I-P control with a sliding mode control algorithm.
Technical Paper

Effects of Fuel Volatility on Combustion Characteristics of PCCI Diesel Engine

2007-07-23
2007-01-1862
In PCCI diesel engine, the fuel is injected much earlier than the injection timing of conventional diesel engines. Exhaust-emission improvements are attained by the lean-premixed combustion. It is expected that fuel properties influence mixture formation and combustion characteristics. In this research, experiments were carried out using a single-cylinder PCCI diesel engine operating on pure fuels with different volatilities. The injection timing and overall equivalence ratio of the premixed spray were varied. The results showed that the maximum heat release rate was smaller for lower-volatility fuel while ISFC was maintained smaller. So the combustion of a lower-volatility fuel would moderately make progress.
Technical Paper

Study on Emission Reducing Method with New Lean NOX Catalyst for Diesel Engines

2007-07-23
2007-01-1933
In recent years, emission regulations have become more stringent as a result of increased environmental awareness in each region of the world. For diesel engines, reducing NOX emissions is a difficult technical challenge.[1],[2],[3],[4]. To respond to these strict regulations, an exhaust gas aftertreatment system was developed, featuring a lean NOX catalyst (LNC) that uses a new chemical reaction mechanism to reduce NOX. The feature of the new LNC is the way it reduces NOX through an NH3-selective catalytic reduction (SCR), in which NOX adsorbed in the lean mixture condition is converted to NH3 in the rich mixture condition and reduced in the following lean mixture condition. Thus, the new system allows the effective reduction of NOX. However, in order to realize cleaner emission gases, precise engine control in response to the state of the exhaust aftertreatment system is essential.
Technical Paper

Development Procedure for Interior Noise Performance by Virtual Vehicle Refinement, Combining Experimental and Numerical Component Models

2001-04-30
2001-01-1538
This paper summarizes the development of a predictive vibro-acoustic full vehicle model of a mid-size sedan and focuses on the engineering analysis procedures used to evaluate the design performance related to engine induced noise and vibration. The vehicle model is build up from a mixture of test-based and finite element component models. FRF Based Substructuring is used for their assembly. The virtual car model is loaded by engine forces resulting from indirect force identification. This force-set includes combustion, inertia, piston slap and crank bearing forces, for engine harmonics from 0.5 to 10th order. Such forced response analysis yields vibration levels at every component, at every interface between components, and interior noise predictions. The target is to provide the vehicle NVH manager with the insight required to identify major causes for peak noise levels and to set targets and develop an action plan for every component design team.
Technical Paper

How to Predict Powertrain Vibration at the Engine Mounting Points Under Running Conditions

2001-04-30
2001-01-1592
Recently, the eigenvalue analysis and the frequency response analysis using the finite element method (FEM) is commonly used, since the vibration characteristic of the powertrain is an important specification which causes the influence on the booming noise and the durability of each parts. However, the eigenvalue analysis and the frequency response analysis cannot take into account of the dynamic behavior of the cranktrain and thenonlinear characteristics. This paper presents a new approach which considers the dynamic behavior of the crankshaft and thenonlinear oil film characteristics of the main bearings and the engine mounts for accurately predicting the vibration level at the engine mounting points under running conditions. By applying this approach to an in-line four cylinder engine, the predicted vibration level is reasonably comparable with experimental result.
Technical Paper

A Decoupled Model of Detailed Fluid Mechanics Followed by Detailed Chemical Kinetics for Prediction of Iso-Octane HCCI Combustion

2001-09-24
2001-01-3612
We have developed a methodology for predicting combustion and emissions in a Homogeneous Charge Compression Ignition (HCCI) Engine. The methodology judiciously uses a fluid mechanics code followed by a chemical kinetics code to achieve great reduction in the computational requirements; to a level that can be handled with current computers. In previous papers, our sequential, multi-zone methodology has been applied to HCCI combustion of short-chain hydrocarbons (natural gas and propane). Applying the same procedure to long-chain hydrocarbons (iso-octane) results in unacceptably long computational time. In this paper, we show how the computational time can be made acceptable by developing a segregated solver. This reduces the run time of a ten-zone problem by an order of magnitude and thus makes it much more practical to make combustion studies of long-chain hydrocarbons.
Technical Paper

Experimental Investigation of Direct Injection-Gasoline for Premixed Compression Ignited Combustion Phasing Control

2002-03-04
2002-01-0418
A direct injection-gasoline (DI-G) system was applied to a heavy-duty diesel-type engine to study the effects of charge stratification on the performance of premixed compression ignited combustion. The effects of the fuel injection parameters on combustion phasing were of primary interest. The simultaneous effects of the fuel stratification on Unburned Hydrocarbon (UHC), Oxides of Nitrogen (NOx), Carbon Monoxide (CO), and smoke emissions were also measured. Engine tests were conducted with altered injection parameters covering the entire load range of normally aspirated Homogeneous Charge Compression Ignited (HCCI) combustion. Combustion phasing tests were also conducted at several engine speeds to evaluate its effects on a fuel stratification strategy.
Technical Paper

Evaporating Spray Concentration Measurementsfrom Small and Medium Bore Diesel Injectors

2002-03-04
2002-01-0219
Vapor concentration measurements were performed for two unit injectors typically found in small- and medium-bore applications under evaporating conditions similar to those experienced in Diesel engines. Ambient gas temperatures of 800 and 1000 K and an ambient density of 15 kg/m3 were investigated using a constant volume combustion-type spray chamber. The exciplex laserinduced fluorescence technique with TMPD/naphthalene doped into the fuel was used to quantitatively determine the vapor-phase concentration and liquid-phase extent. The vapor-phase concentration was quantified using a previously developed method that includes corrections for the temperature dependence of the TMPD fluorescence, laser sheet absorption, and the laser sheet intensity profile. The effect of increasing ambient temperature (1000 vs. 800 K) was significant on intact liquid length, and on the spray-spreading angle in the early portion of the injection period.
Technical Paper

Detailed Diesel Exhaust Particulate Characterization and DPF Regeneration Behavior Measurements for Two Different Regeneration Systems

2007-04-16
2007-01-1063
Three distinct types of diesel particulate matter (PM) are generated in selected engine operating conditions of a single-cylinder heavy-duty diesel engine. The three types of PM are trapped using typical Cordierite diesel particulate filters (DPF) with different washcoat formulations and a commercial Silicon-Carbide DPF. Two systems, an external electric furnace and an in-situ burner, were used for regeneration. Furnace regeneration experiments allow the collected PM to be classified into two categories depending on oxidation mechanism: PM that is affected by the catalyst and PM that is oxidized by a purely thermal mechanism. The two PM categories prove to contribute differently to pressure drop and transient filtration efficiency during in-situ regeneration.
Technical Paper

Gasoline Distillation Effect on Vehicle Cold Start Driveability

2007-10-29
2007-01-4073
Cold start vehicle driveability performance depends on many parameters, one of which is the distillation character of the fuel. In the late 90's, a gasoline driveability index (DI) was developed for spark ignited combustion vehicles by a consortium of automotive and petroleum industry scientists based on correlation studies between controlled fuel quality matrices and vehicle performance under specific ambient conditions. The DI equation uses a weighted sum of gasoline distillation temperatures at the 10, 50 and 90 percent evaporation volumes, commonly called T10, T50 and T90. These three distillation volatility points are specified by the ASTM International D 4814 fuel specification and are seasonally adjusted. This paper studies the cold start driveability performance of Federal EPA Bin 5 and Bin 8 vehicles with respect to fuel distillation characteristics at temperatures other than T10, T50 and T90.
Technical Paper

Study on HCCI-SI Combustion Using Fuels Ethanol Containing

2007-10-29
2007-01-4051
Bio-ethanol is one of the candidates for automotive alternative fuels. For reduction of carbon dioxide emissions, it is important to investigate its optimum combustion procedure. This study has explored effect of ethanol fuels on HCCI-SI hybrid combustion using dual fuel injection (DFI). Steady and transient characteristics of the HCCI-SI hybrid combustion were evaluated using a single cylinder engine and a four-cylinder engine equipped with two port injectors and a direct injector. The experimental results indicated that DFI has the potential for optimizing ignition timing of HCCI combustion and for suppressing knock in SI combustion under fixed compression ratio. The HCCI-SI hybrid combustion using DFI achieved increasing efficiency compared to conventional SI combustion.
Technical Paper

Combustion and Lift-Off Characteristics of n-Heptane Sprays Using Direct Numerical Simulations

2007-10-29
2007-01-4136
Fundamental simulations using DNS type procedures were used to investigate the ignition, combustion characteristics and the lift-off trends of a spatially evolving turbulent liquid fuel jet. In particular, the spatially evolving n-Heptane spray injected in a two-dimensional rectangular domain with an engine like environment was investigated. The computational results were compared to the experimental observations from an optical engine as reported in the literature. It was found that an initial fuel rich combustion downstream of the spray tip is followed by diffusion combustion. Investigations were also made to understand the effects of injection velocity, ambient temperature and the droplet radius on the lift-off length. For each of these parameters three different values in a given range were chosen. For both injection velocity and droplet radius, an increase resulted in a near linear increase in the lift-off length.
Technical Paper

A Transient Heat Transfer System for Research Engines

2007-04-16
2007-01-0975
An ongoing goal of the Powertrain Control Research Laboratory (PCRL) at the University of Wisconsin-Madison has been to expand and improve the ability of the single cylinder internal combustion research engine to represent its multi-cylinder engine counterpart. To date, the PCRL single cylinder engine test system is able to replicate both the rotational dynamics (SAE #2004-01-0305) and intake manifold dynamics (SAE #2006-01-1074) of a multi cylinder engine using a single cylinder research engine. Another area of interest is the replication of multi-cylinder engine cold start emissions data with a single-cylinder engine test system. For this replication to occur, the single-cylinder engine must experience heat transfer to the engine coolant as if it were part of a multi-cylinder engine, in addition to the other multi-cylinder engine transient effects.
Technical Paper

Initial Estimation of the Piston Ring Pack Contribution to Hydrocarbon Emissions from a Small Engine

2007-10-29
2007-01-4014
The contribution to the engine-out hydrocarbon (HC) emissions from fuel that escapes the main combustion event in piston ring crevices was estimated for an air-cooled, V-twin utility engine. The engine was run with a homogeneous pre-vaporized mixture system that avoids the presence of liquid films in the cylinder, and their resulting contribution to the HC emissions. A simplified ring pack gas flow model was used to estimate the ring pack contribution to HC emissions; the model was tested against the experimentally measured blowby. At high load conditions the model shows that the ring pack returns to the cylinder a mass of HC that exceeds that observed in the exhaust, and thus, is the dominant contributor to HC emissions. At light loads, however, the model predicts less HC mass returned from the ring pack than is observed in the exhaust. Time-resolved HC measurements were performed and used to assess the effect of combustion quality on HC emissions.
Technical Paper

Piston-Liner Crevice Geometry Effect on HCCI Combustion by Multi-Zone Analysis

2002-10-21
2002-01-2869
A multi-zone model has been developed that accurately predicts HCCI combustion and emissions. The multi-zone methodology is based on the observation that turbulence does not play a direct role on HCCI combustion. Instead, chemical kinetics dominates the process, with hotter zones reacting first, and then colder zones reacting in rapid succession. Here, the multi-zone model has been applied to analyze the effect of piston crevice geometry on HCCI combustion and emissions. Three different pistons of varying crevice size were analyzed. Crevice sizes were 0.26, 1.3 and 2.1 mm, while a constant compression ratio was maintained (17:1). The results show that the multi-zone model can predict pressure traces and heat release rates with good accuracy. Combustion efficiency is also predicted with good accuracy for all cases, with a maximum difference of 5% between experimental and numerical results.
Technical Paper

Development of a Magnetic Coupling Water Pump for a Four-Stroke 50cm3 Scooter Engine

2002-03-04
2002-01-0858
In the development of a magnetic-coupling water pump, the pulling-out (disengagement) of a coupling that led to the stopping of an impeller was a concern. Upon analysis of the behavior of the magnetic coupling, presence of two types of the pulling-out was found, that is, the pulling-out resulting from a lack of transfer torque in the high-speed revolutions and the pulling-out due to the resonance of an inner magnet and an outer magnet. Main factors that affect the pulling-out are the angular velocity input to the drive side, the moment of inertia of the driven side, characteristics of the magnetic coupling, and a damping from coolant. Using a measurement and simulation of the behavior of the water pump, factors were analyzed and the process of pulling-out was clarified. As a result, design specifications that prevented the pulling-out were established.
Technical Paper

Design of a Hydraulic Wheel Pump/Motor for a Hydrostatic Automobile

2002-03-19
2002-01-1349
Using a low-speed high-torque (LSHT) pump/motor to provide the speed range and torque for a hydrostatic automobile offers a number of advantages over using a high-speed low-torque pump/motor, combined with a gear reducer. However, there appear to be no LSHT units commercially available that have true variable displacement capability. Because of this void, a variable displacement pump/motor has been designed and built that could provide a direct drive for each wheel of a hydrostatic automobile. The unit uses some components such as the cylinder block, piston and modified rotating case from a commercially available radial piston pump/motor. Initial preliminary testing of the pump/motor indicates that it has good efficiency and performance characteristics, and, with further development should be very attractive for automotive use. This paper focuses on the design and kinematics of the device.
Technical Paper

69 Development of Gear Train Behavioral Analysis Technologies Considering Non-linear Elements

2002-10-29
2002-32-1838
A numerical calculation method, which enables the analysis of gear train behavior including non-linear elements in a motorcycle engine, was established. During the modeling process, it was confirmed that factors such as bearing distortion, radial bearing clearance and elastic deformation of a tooth flank could not be neglected because they effect the rotation behavior. To keep a high accuracy, those factors were included in the simulation model, after they were converted into the rigidity elements along the rotational direction of each gear model. In addition, the model was combined with a crankshaft behavior calculation model for a driving and excitation source. A time domain numerical integration method was used to perform the transient response simulation across a wide range of engine speeds. A jump phenomenon of response behavior of the driven gear was predicted that is a characteristic of non-linear response. The phenomenon was also observed in a physical test.
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