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The increasing use of gasoline direct injection (GDI) engines coupled with the implementation of new particulate matter (PM) and particle number (PN) emissions regulations requires new emissions control strategies. Gasoline particulate filters (GPFs) present one approach to reduce particle emissions. Although primarily composed of combustible material which may be removed through oxidation, particle also contains incombustible components or ash. Over the service life of the filter the accumulation of ash causes an increase in exhaust backpressure, and limits the useful life of the GPF. This study utilized an accelerated aging system to generate elevated ash levels by injecting lubricant oil with the gasoline fuel into a burner system. GPFs were aged to a series of levels representing filter life up to 150,000 miles (240,000 km). The impact of ash on the filter pressure drop and on its sensitivity to soot accumulation was investigated at specific ash levels.

In the conventional approval test method of fuel consumption for heavy-duty diesel vehicles currently in use in Japan, the fuel consumption under the transient test cycle is calculated by integrating the instantaneous fuel consumption rate referred from a look-up table of fuel consumptions measured under the steady state conditions of the engine. Therefore, the transient engine performance is not considered in this conventional method. In this study, a highly accurate test method for fuel consumption in which the map-based fuel consumption rate is corrected using the transient characteristics of individual engines was developed. The method and its applicability for a heavy-duty diesel engine that complied with the Japanese 2009 emission regulation were validated.

Fuel consumption and exhaust gas emission regulations are being tightened around the world year by year. Electric vehicles are needed to reduce carbon dioxide emissions. Especially, Plug-in hybrid heavy-duty vehicles (PHEVs) are expected to become widespread. PHEVs enable all-electric modes, as well as hybrid modes, using both engines and electric motors, but the control system significantly affects the characteristics of fuel consumption and gas emission. In this study, we used new testing machine (we call extended HILS) to analyze the fuel consumption and gas emission for different plug-in hybrid control systems and investigated the optimal control method for PHEVs.

Application of biodiesel fuel (BDF) to diesel engine is very effective to reduce CO2 emission, because bio-diesel is carbon neutral in principle. However, when biodiesel was applied to conventional diesel engines without modification for biodiesel, NOx emission was increased by the change in fuel characteristics. It is necessary to introduce some strategies into diesel engines fuelled with biodiesel for lower NOx emission than conventional diesel fuel case. The purpose of this study is to reveal that exhaust gas recirculation (EGR) is one of the solutions for the reduction of NOx emission and meeting the future emission regulations when using biodiesel. Neat Rapeseed oil methyl ester (RME) as a biodiesel (B100) was applied to diesel engines equipped with high pressure loop (HPL) EGR system and low pressure loop (LPL) EGR system. Cooled HPL EGR was increased during steady-state operations and JE05 transient mode tests.

Application of biodiesel fuel (BDF) to diesel engine is very effective to reduce CO2 emission, because biodiesel is carbon neutral in principle. However, biodiesels yield an increase in NOx emission from conventional diesel engine, compared with diesel fuel case. Therefore, some strategies are needed for meeting the future emission regulations when using biodiesel. In this study, rapeseed oil methyl ester (RME) was applied to diesel engine equipped with exhaust gas recirculation (EGR) system and NOx storage reduction (NSR) catalyst. NOx reduction rate of NSR catalyst was drastically decreased by using RME, even if injection quantity of RME for rich spike was enhanced. However, an increase in EGR rate could reduce NOx emission without the deterioration in smoke and PM emissions.

This paper presents an improved exhaust emission simulation model that takes into account fuel transportation behavior in order to obtain more precise air-fuel ratio control, which is needed to meet stringent exhaust emission standards. This simulation model is based on experimental formulas for air and fuel behavior in the intake manifold, especially during transient engine operation. Fuel behavior, including the effect of wall flow on the air-fuel ratio, is obtained analytically. Predictions are then made of the exhaust emissions from a car operated under official driving schedules. The new simulation model is a useful tool in the design and development of fuel supply control systems. An outline of the new model is presented first along with a comparison of the calculated and experimental results. The air-fuel ratio control strategy derived with this model is then described.

Nissan Motor has put on the European SUV market a 2.2-L direct-injection diesel engine with a diesel particulate filter (DPF) system that complies with the EURO IV emission regulations. This paper describes the DPF system, cooperative control of a variable geometry turbo (VGT) and exhaust gas recirculation (EGR), and a high-accuracy lambda control adopted for this engine. In order to achieve a compact DPF, the high-accuracy lambda control was developed to reduce variation in engine-out particulate matter (PM) emissions. Moreover, the accuracy of the technique for predicting the quantity of PM accumulation was improved for reliable detection of the DPF regeneration. Prediction error for PM accumulation increases during transient operation. Control logic was adopted to correct the PM prediction according to lambda fluctuation detected by an observer for lambda at cylinder under transient operating conditions. The observer is corrected lambda sensor output.

A variable compression ratio (VCR) technology, that has a new piston-crankshaft mechanism with multi links, has been patented and developed by Nissan for some years (This technology has been detailed in previous SAE paper 2003-01-0921 and 2005-01-1134). This paper will present the use of this VCR technology for Diesel engine. The objective set with the use of VCR for Diesel engine is mainly to reduce as much as possible engine out emission to prepare for long-term, more strict emission standards. Results presented will include the description of the 2l Diesel VCR engine and its VCR mechanism adapted to Diesel constraints. Combustion tests have been performed with the use of HCCI (Homogeneous Charge Compression Ignition) combustion. This technology is still in a research phase in Renault: the adaptation of VCR technology to a Diesel engine consists in the modification of several parts with the addition of lower links, control links and control shaft.

Measurements of particulate matter (PM) from spark ignition (SI) engine exhaust using dilution tunnels will become more prevalent as emission standards are tightened. Hence, a study of the dilution process was undertaken in order to understand how various dilution related parameters affect the accuracy with which PM sizes and concentrations can be determined. A SI and a compression ignition (CI) engine were separately used to examine parameters of the dilution process; the present work discusses the results in the context of SI exhaust dilution. A Scanning Mobility Particle Sizer (SMPS) was used to measure the size distribution, number density, and volume fraction of PM. Temperature measurements in the exhaust pipe and dilution tunnel reveal the degree of mixing between exhaust and dilution air, the effect of flowrate on heat transfer from undiluted and diluted exhaust to the environment, and the minimum permissible dilution ratio for a maximum sample temperature of 52°C.

The Diesel Particulate Filter (DPF) system has been developed as one of key technologies to comply with tight diesel PM emission regulations. For the DPF control system, it is necessary to maintain temperature inside the DPF below the allowable service temperature, especially during soot regeneration to prevent catalyst deterioration and cracks. Therefore, the evaluation of soot regeneration is one of the key development items for the DPF system. On the other hand, regeneration evaluation requires a lot of time and cost since many different regeneration conditions should be investigated in order to simulate actual driving. The simulation tool to predict soot regeneration behavior is a powerful tool to accelerate the development of DPF design and safe regeneration control strategies. This paper describes the soot regeneration model applied to fuel additive and catalyzed types, and shows good correlation with measured data.

Generally, cobalt-contained sintered materials have mainly been applied for exhaust valve seat inserts (VSI). However, there is a trend to restrict the use of cobalt as well as lead environmental law, and cobalt is expensive. To solve these problems, a new exhaust VSI on the assumption of being cobalt and lead free, applicable for conventional engines, having good machinability, and with a reduced cost was developed. The new exhaust VSI is a material dispersed with two types of hard particles, Fe-Cr-C and Fe-Mo-Si, in the matrix of an Fe-3.5mass%Mo at the ratio of 15 mass % and 10 mass % respectively.

Impact of oil-derived ash on the pressure drop of continuous regeneration-type diesel particulate filter (CR-DPF) was investigated through 600hrs running test at maximum power point on a 6.9L diesel engine, which meets the Japanese long-term emission regulations enacted in 1998, using approximately 50ppm sulfur content fuel. Sulfated ash content of test oils were varied as 0.96, 1.31, and 1.70 mass%, respectively. During the running test, the exhaust pressure drop through CR-DPF was measured. And after the test, the ventilation resistance through CR-DPF was also evaluated before and after the baking process, which was applied to eliminate the effect of soot accumulated in CR-DPF. The results revealed that the less sulfated ash in oil gave rise to lower pressure drop across CR-DPF. According to microscope examination of the baked DPF, ash was mainly accumulated on the wall surface of CR-DPF, and that seemed to be related to the magnitude of pressure drop caused by ash.

Four urea SCR systems were developed and evaluated on a C/D and on the road to investigate their potential for Japanese emission regulations in 2005 and beyond. Test results showed that NOx conversion ratios were 50 to 70% during the Japanese D13 mode cycle, and the ratios under the transient driving cycle were lower than those tested during a steady state. Unregulated emissions, such as benzene, aldehyde and benzo[a]pyrene, existed either at a trace level using the oxidation catalyst, or lower than a base diesel engine, when no oxidation catalyst was used. The health effects of particulate matter emitted from the SCR system were almost the same as those from conventional diesel engines, as evaluated by the Ames test and in vitro micronucleus test. Thermal degradation products, such as cyanuric acid and melamine, were two to four figures lower compared with the toxicological information of Safety Information Resources Inc. (SIRI).

This paper is an attempt to estimate the traffic demand of private vehicles in the Philippines and Thailand toward 2030. Estimation of road traffic volume is one of the most important elements for determining fuel consumption and emission gas levels. The level of passenger car ownership is still low, but there has been a distinct shift toward passenger cars due to the lack of mass transport. In Asian countries, inspection and maintenance and emission standards are the most important policy measures. The projections of car stock are evaluated as the emissions of PM, CO and NOx by applying these policy measures in the case of Thailand.

This paper describes the emission reduction technologies applied to 4- and 6-cylinder engines used on Japanese market models certified as ultra-low emission vehicles (U-LEVs) in Japan. To qualify for this rigorous U-LEV certification, a vehicle must reduce hydrocarbon (HC) and nitrogen oxide (NOx) emissions by an additional 75% from the levels mandated by Japan's 2000 exhaust emission regulations. Nearly all Nissan Japanese models fitted with a gasoline engine, ranging from in-line 4-cylinder engines to V6 engines, have now been certified as U-LEVs. This has been accomplished by further improving the emission reduction technologies that were developed for the Sentra CA, which was launched in the U.S. market in 2000 as the world's first gasoline-fueled vehicle to qualify for Partial Zero Emission Vehicle (P-ZEV) credits from the California Air Resources Board. The specific new technologies involved are as follows.

The 1997 Kyoto protocol came into effect in February, 2005 to reduce greenhouse gases within the period 2008-2012 by at least 5 % with respect to 1990 levels. Application of biodiesel fuel (BDF) to diesel engine is very effective to reduce CO2 emission, because BDF is carbon neutral in principle. The purpose of this project is to produce a light-duty biodiesel truck which can be suitable for emission regulation in next generation. The effect of BDF on the performance and emissions of modern diesel engine which was equipped with the aftertreatment for PM and NOx emissions was investigated without modifications of engine components and parameters, as a first step for research and development of biodiesel engine. Rapeseed oil methyl ester (RME) was selected in behalf of BDF, and combustion characteristics, engine performance and exhaust emissions were made a comparison between RME and petroleum diesel fuel by steady operation and Japan transient mode (JE05) tests.

HC emission standards will be tightened during the 1990's in the US. A key issue in reducing HC emission is improving the warm-up characteristics of catalysts during the cold start of engines. For this purpose, studies are under way on reduction of heat mass of ceramic substrates. Reduction of cell walls in substrates to thickness smaller than the current thickness of 12mil or 6mil has resulted in reduced heat mass, and also reduced flow restriction of substrates. The warm-up characteristics of low bulk density catalysts are better than those of high bulk density, i.e., the warm-up characteristics of thinner wall or lower cell density catalysts are better than those of thicker wall or higher cell density catalysts. A relationship between geometric surface area and warm-up characteristics is observed.

Emission regulations for diesel-powered vehicles have been gradually tightening. Installation of after-treatment devices such as diesel particulate filters (DPF), NOx storage reduction (NSR) catalysts, and so on is indispensable to satisfy rigorous limits of particulate matter (PM) and nitrogen oxides (NOx). Japan Clean Air Program II Oil Working Group (JCAPII Oil WG) has been investigating the effect of engine oil on advanced diesel after-treatment devices. First of all, we researched the impact of oil-derived ash on continuous regeneration-type diesel particulate filter (CR-DPF), and already reported that the less sulfated ash in oil gave rise to lower pressure drop across CR-DPF [1]. In this paper, impact of oil-derived sulfur and phosphorus on NSR catalyst was investigated using a 4L direct injection common-rail diesel engine with turbo-intercooler. This engine equipped with NSR catalyst meets the Japanese new short-term emission regulations.

Currently, states that are out of compliance with the National Ambient Air Quality Standards must, according to the Clean Air Act Amendments of 1990 (CAAA), develop and implement control strategies that demonstrate specific degrees of reduction in emissions-with the degree of reduction depending upon the severity of the problem. One tool that has been developed to aid regulators in both deciding an appropriate course of action and to demonstrate the desired reductions in mobile emissions is EPA's Mobile 5a emission estimation model. In our study, Mobile 5a has been used to examine the effects of regulatory strategies, as applied to the Northeast United States, on vehicle emissions under worst-case ozone-forming conditions.

This paper presents a new-generation, lightweight, 3-liter V6 engine that has been developed for use in the next Nissan Maxima. The distinctive features of this new engine, VQ30DE, is its compact, lightweight design and excellent fuel economy. The basic construction of the engine is characterized by its 60-degree V6 configuration, chain-driven DOHC and high-pressure die cast aluminum cylinder block. A two-way cooling system was adopted with the aim of shortening the warm-up time of the cylinder liners. The new engine has been designed to comply with the tougher emission standards, the OBD-II requirements and California's new evaporative emission standard.