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When performing catalyst modeling and parameter tuning it is desirable that the experimental data contain both transient and stationary points and can be generated over a short period of time. Here a method of creating such concentration transients for a full scale engine rig system is presented. The paper describes a valuable approach for changing the composition of engine exhaust gas going to a DOC (or potentially any other device) by conditioning the exhaust gas with an additional upstream DOC and/or SCR. By controlling the urea injection and the DOC bypass a wide range of exhaust compositions, not possible by only controlling the engine, could be achieved. This will improve the possibilities for parameter estimation for the modeling of the DOC.

Investigations of low drag shapes for passenger vehicles were conducted in the 1930s but production cars of today have yet to approach the potential drag coefficients shown by that early research. Furthermore, the adoption of low drag styles has been resisted because of a perception of compromise to the exterior style and so recent aerodynamic developments have concentrated on changes to non-styled surfaces. However, environmental and ecological pressures are placing increasing demands on manufacturers to produce energy efficient vehicles and the contribution of aerodynamics in that equation is increasing, particularly with the adoption of technologies such as regenerative braking and measurements being made using more real-world use driving cycles. Relying on non-styled surfaces alone for drag reduction is unlikely to be sufficient to deliver the improvements required.

The increasing severity in emission standards around the world has been accompanied by the development of more active, durable catalysts. With a view to investigating the effects of high thermal aging on the catalyst performance and structure, the relationships of washcoat composition, washcoat structure, and PGM location with respect to catalyst activity were clarified using a model gas test, as well as physical and chemical characterization methods. The influence of newly developed washcoat components and PGM location on catalyst performance are also demonstrated by engine bench tests. The results obtained in this study indicate the newly developed Pt/Rh catalyst techologies are appropriate for future applications in which the catalyst will be exposed to extremely high temperature and flowrates.

With the ever increasing demand on automotive manufactures to reduce lead times, improve performance, add air conditioning, meet noise and pollution legislation the need to evaluate and improve cooling system performance at the design stage is becoming increasingly important. The cooling system is taken to encompass the full air path of grills, inlet plenum, cooling pack, under bonnet resistance and outlet to the free stream. This paper describes the main structure of a PC based computer program which is being developed to permit the cooling system performance to be optimized at the vehicle concept stage or prior to major updates to a model, which could be for example front end styling or a change of engine. Also discussed are details of how the air paths through the cooling pack, and the system resistances from the inlet grill to the engine compartment outlet are determined.

It has long been recognized that the key to achieving stringent emission standards such as ULEV is the control of cold-start hydrocarbons. This paper describes a new approach for achieving excellent cold-start hydrocarbon control. The most important component in the system is a catalyst that is highly active at ambient temperature for the exothermic CO oxidation reaction in an exhaust stream under net lean conditions. This catalyst has positive order kinetics with respect to CO for CO oxidation. Thus, as the concentration of CO in the exhaust is increased, the rate of this reaction is increased, resulting in a faster temperature rise over the catalyst.

The molecular filtration of sulfur components in ultra low sulfur diesel (ULSD) fuel is described. A comprehensive screening of potential sulfur removal chemistries has yielded a sorbent which has the capability to efficiently remove organo-sulfur components in ULSD fuel. This sorbent has been used to treat ULSD fuel on a heavy duty engine equipped with NOx adsorber after-treatment technology and has been shown to lengthen the time between desulfation steps for the NOx adsorber. The fuel properties, cetane number and aromatics content, etc., have not been changed by the removal of the sulfur in the fuel with the exception of the lubricity which is reduced.

The implementations of the Tier 2 and LEVII emission levels require fast catalyst light-off and fast closed loop control through high-speed engine management. The paper describes the development of innovative catalyst designs. During the development thermal and mechanical boundary conditions were collected and component tests conducted on test rigs to identify the emission and durability performance. The products were evaluated on a Super Imposed Test Setup (SIT) where thermal and mechanical loads are applied to the test piece simultanously and results are compared to accelerated vehicle power train endurance runs. The newly developed light-off catalyst with Perforated Foil Technology (PE) showed superior emission light-off characteristic and robustness.

The topic of energy management in Hybrid Electric Vehicles (HEVs) has received a great deal of recent attention. Various methods have been proposed to develop algorithms which manage energy flows within HEVs so that to optimally exploit energy storage capability of the battery and reduce fuel consumption while maintaining battery State of Charge. In addition, to the rule-based approaches, systematic optimal control methods based on deterministic and stochastic dynamic programming have been explored for HEV energy management optimization. In this paper, another novel framework based on the application of game theory is proposed, in which the HEV operation is viewed as a non-cooperative game between the driver and the powertrain.

The SNR-technique is a new NOx aftertreatment system for lean burn gasoline and diesel applications. The objective of SNR is NOx removal from lean exhaust gas by NOx adsorption and subsequent selective external recirculation and decomposition of NOx in the combustion process. The SNR-project is composed of two major parts. Firstly the development of NOx adsorbents which are able to store large quantities of NOx in lean exhaust gas, and secondly the NOx decomposition by the combustion process. Emphasis of this paper is the investigation of NOx reduction in the combustion process, including experimental investigation and numerical simulation. The NOx decomposition process has been proven in diesel and lean-burn gasoline engines. Depending on the type of engine NOx-conversion rates up to 90 % have been observed. Regarding the complete SNR-system, including the efficiency of the adsorbing material and the NOx decomposition by the combustion, a NOx removal of more than 50% is achievable.

Selective NOx recirculation (SNR), involving adsorption, selective external recirculation and decomposition of the NOx by the combustion process, is itself a promising technique to abate NOx emissions. Three types of materials containing Ba: barium aluminate, barium tin perovskite and barium Y-zeolites have been developed to adsorb NOx under lean-burn or Diesel conditions, with or without the presence of S02. All these materials adsorb NO2 selectively (lean-burn conditions), and store it as nitrate/nitrite species. The desorption takes place by decomposition of these species at higher temperatures. Nitrate formation implies also sulfate formation in the presence of SO2 and SO3, while the NO2/SO2 competition governs the poisoning of such catalysts.

The objective of this effort was to develop an understanding of how different converter substrate cell structures impact tailpipe emissions and pressure drop from a total systems perspective. The cell structures studied were the following: The catalyst technologies utilized were a new technology palladium only catalyst in combination with a palladium/rhodium catalyst. A 4.0-liter, 1997 Jeep Cherokee with a modified calibration was chosen as the test platform for performing the FTP test. The experimental design focused on quantifying emissions performance as a function of converter volume for the different cell structures. The results from this study demonstrate that the 93 square cell/cm2 structure has superior performance versus the 62 square cell/cm2 structure and the 46 triangle cell/cm2 structure when the converter volumes were relatively small. However, as converter volume increases the emissions differences diminish.

The performance characteristics of a commercial lean-NOX trap catalyst were evaluated between 200 and 500°C, using H2, CO, and a mixture of both H2 and CO as reductants before and after different high-temperature aging steps, from 600 to 750°C. Tests included NOX reduction efficiency during cycling, NOX storage capacity (NSC), oxygen storage capacity (OSC), and water-gas-shift (WGS) and NO oxidation reaction extents. The WGS reaction extent at 200 and 300°C was negatively affected by thermal degradation, but at 400 and 500°C no significant change was observed. Changes in the extent of NO oxidation did not show a consistent trend as a function of thermal degradation. The total NSC was tested at 200, 350 and 500°C. Little change was observed at 500°C with thermal degradation but a steady decrease was observed at 350°C as the thermal degradation temperature was increased.

Modeling of SCR in diesel exhaust systems with injection of urea spray is complex and challenging but many models use only the conversion observed at the brick exit as a test of the model. In this study, the case modeled is simplified by injecting ammonia gas in nitrogen in place of urea, but the spatial conversion profiles along the SCR brick length at steady state are investigated. This is a more rigorous way of assessing the ability of the model to simulate observations made on a test exhaust system. The data have been collected by repeated engine tests on eight different brick lengths, all which were shorter than a standard-sized SCR. The tests have been carried out for supplied NH₃ /NOx ratios of a 1.5, excess ammonia, a 1.0, balanced ammonia, and a 0.5, deficient ammonia. Levels of NO, NO₂ and NH₃ have been measured both upstream and downstream of the SCR using a gas analyzer fitted with ammonia scrubbers to give reliable NOx measurements.

This paper investigates the flow maldistribution across the monolith of an axisymmetric catalyst assembly fitted to a pulsating flow test rig. Approximately sinusoidal inlet pulse shapes with relatively low peak/mean ratio were applied to the assembly with different amplitudes and frequencies. The inlet and outlet velocities were measured using Hot Wire Anemometry. Experimental results were compared with a previous study, which used inlet pulse shapes with relatively high peak/mean ratios. It is shown that (i) the flow is more maldistributed with increase in mass flow rate, (ii) the flow is in general more uniformly distributed with increase in pulsation frequency, and (iii) the degree of flow maldistribution is largely influenced by the different inlet velocity pulse shapes. Transient CFD simulations were also performed for the inlet pulse shapes used in both studies and simulations were compared with the experimental data.

Future US emissions limits are likely to mean a sophisticated nitrogen oxide (NOx) reduction technique is required for all vehicles with a diesel engine, which is likely to be either NOx trap or selective catalytic reduction (SCR) technology. To investigate the potential of SCR for NOx reduction on a light duty vehicle, a current model vehicle (EUII M1 calibration), of inertia weight 1810 kg, was equipped with an urea-based SCR injection system and non-vanadium, non-zeolitic SCR catalysts. To deal with carbon monoxide (CO), hydrocarbon (HC) and volatile organic fraction (VOF), a diesel oxidation catalyst was also incorporated into the system for most tests. Investigations into the effect of placing the oxidation catalyst at different positions in the system, changing the volume of the SCR catalysts, increasing system temperature through road load changes, varying the SCR catalyst composition, and changing the urea injection calibration are discussed.

This paper describes the development of new high performance three-way catalyst (TWC) formulations with improved activity and enhanced thermal stability. These new TWC formulations enable the converter to be fitted closer to the engine and allow this future legislation to be met with catalysts using PGM levels significantly lower than those currently being employed. The performance benefits of these advanced platinum- and palladium-based catalysts are demonstrated on a number of different vehicles after bench-engine ageing.

The influence of catalyst volume, cell density and precious metal loading on the catalyst efficiency were investigated to design a low cost catalyst system. In a first experiment the specific loading was kept constant for a 500cpsi and a 900cpsi substrate. In a second experiment the palladium loading was reduced on the 900cpsi substrate and the same PM loading was applied to a 1200cpsi substrate with lower volume. Finally the loading was further reduced for the 1200cpsi substrate. The following parameters were studied after aging: Catalyst performance of standard cell density compared to high cell density technology Light-off performance and catalyst efficiency as a function of Palladium loading and substrate cell density Catalyst efficiency as a function of AFR biasing The performance of the aged catalysts was investigated in a lambda sweep test and in light-off tests at an engine bench.

This paper describes the coupling of a 1D engine simulation code (Ricardo WAVE) to a 3D CFD code (STAR-CD) to study the flow behaviour inside a Close-Coupled Catalytic converter (CCC). A SI engine was modelled in WAVE and the CCC modelled in STAR-CD. The predictions of the stand-alone WAVE model were validated against engine bed tests before the coupled 1D/3D simulations were performed at 3000 RPM WOT for both motored and firing conditions. The predicted exhaust velocities downstream of the catalyst monolith in the coupled simulations matched fairly well with Laser Doppler Anemometry (LDA) measurements.

PICASSOS was a UK government funded programme to improve the ability of automotive supply chains to develop complex software-intensive systems with high safety assurance and at an acceptable cost. This was executed by a consortium of three universities and five companies including an automotive OEM and suppliers. Three major elements of the PICASSOS project were: use of automated model based verification technology utilising formal methods; application of this technology in the context of ISO 26262; and evaluation to measure the impact of this approach to inform key management decisions on the costs, benefits and risks of applying this technology on live projects. The project spanned system level design and software development. This was achieved by using a unified model based process incorporating SysML at the system level and using Simulink and Stateflow auto-coded into C at the software level.

Most ground vehicles related accidents occur when the friction demand to perform a maneuver with a certain vehicle and tires exceeds the coefficient of friction of the pavement surface. As generally known, the forces and moments acting on the vehicle body are mainly generated at the tire-road surface interface. The common characteristics of tire forces on any surface include a linear region where the forces vary linearly with respect to the relative slip values; and a nonlinear region where the forces saturate and may even start decreasing. The experience of most of the daily drivers on the roads is limited within this linear region where the dynamic behavior of the vehicle remains proportional to the driver’s inputs. Therefore, an unexpected change in tire or surface characteristics (due to a change in surface friction, large driver inputs, etc.) may easily cause the driver to panic and/or to lose his/her ability to maintain a stable vehicle.