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Selective catalyst reduction (SCR) using cordierite honeycomb substrate is generally used as a DeNOx catalyst for diesel engines exhaust in both on-road and commercial off-highway vehicles to meet today’s worldwide emission regulations. Worldwide NOx emission regulations will become stricter, as represented by CARB2027 and EuroVII. Technologies which can achieve further lower NOx emissions are required. Recently, several technologies, like increased SCR catalyst loading amount on honeycomb substrates, and additional SCR catalyst volume in positions closer to the engine are being considered to achieve ultra-low NOx emissions. However, undesirable pressure drop increase and enlarging after treatment systems will be caused by adopting these technologies. Therefore, optimization of the material and honeycomb cell structure for SCR is inevitable to achieve ultra-low NOx emissions, while minimizing any system drawbacks.

Fleet average SULEV30 emissions over FTP-75 must be met under full implementation of US Tier 3/LEV III emission regulation in 2025. The majority of SULEV30 certified 2021 model year vehicles are equipped with ≤ 2L displacement engines and some models adopt hybrid powertrain systems. Pickup trucks account for > 20% of passenger vehicles in the US. They could represent a quick route to meet fleet average SULEV30 targets. The newest pickup truck models are typically ULEV50 or ULEV70 certified. To reach SULEV30 or lower emission category, total tailpipe emissions must be reduced by more than 40%. Improvement of cold start emission is essential because over 70% of regulated emission is emitted during the first 60 seconds of a drive cycle with current engine and aftertreatment technology. High porosity (HP) ceramic substrate is designed to reduce thermal mass and time required to reach three-way catalyst (TWC) active temperature compared to conventional ceramic substrates.

In recent years, electrically heated catalysts (EHCs) have been developed to achieve lower emissions. In several EHC heating methods, the direct heating method, which an electric current is applied directly to the catalyst substrate, can easily activate the catalyst before engine start-up. The research results reported on the use of the direct heating EHC to achieve significant exhaust gas purification during cold start-up [1]. From the perspective of catalyst loading, ceramics is considered to be a better material for the substrate than metal due to the difference in coefficient of thermal expansion between the catalyst and the substrate, but the EHC made of ceramics has difficulties such as controllability of the current distribution, durability and reliability of the connection between the substrate and the electrodes.

Ammonia Selective Catalytic Reduction (SCR) is adapted for a variety of applications to control nitrogen oxides (NOx) in diesel engine exhaust. The most commonly used catalyst for SCR in established markets is Cu-Zeolite (CuZ) due to excellent NOx conversion and thermal durability. However, most applications in emerging markets and certain applications in established markets utilize vanadia SCR. The operating temperature is typically maintained below 550°C to avoid vanadium sublimation due to active regeneration of the diesel particulate filter (DPF), or some OEMs may eliminate the DPF because they can achieve particulate matter (PM) standard with engine tuning. Further improvement of vanadia SCR durability and NOx conversion at low exhaust gas temperatures will be required in consideration of future emission standards.

Ammonia Selective Catalytic Reduction (SCR) is a key emission control component utilized in diesel engine applications for NOx reduction. There are several types of SCR catalyst currently in the market: Cu-Zeolite, Fe-Zeolite and Vanadia. Diesel vehicle and engine manufacturers down select their production SCR catalyst primarily based on vehicle exhaust gas temperature operation, ammonia dosing strategy, fuel quality, packaging envelope and cost. For Vanadia SCR, the operating temperature is normally controlled below 550oC to avoid vanadium sublimation. In emerging markets, the Vanadia SCR is typically installed alone or downstream of the DOC with low exhaust gas temperature exposure. Vanadia SCR is also utilized in some European applications with passive DPF soot regeneration. However, further improvement of Vanadia SCR NOx conversion at low exhaust gas temperatures will be required to meet future emission regulations (i.e.: HDD Phase 2 GHG).

Honeycomb substrates are widely used to reduce harmful emissions from gasoline engines and are exposed to numerous thermal shocks during their lifetime making thermal shock resistance one of the key factors in designing honeycomb substrates. More stringent emission regulations will require the honeycomb substrates to be lighter in weight to improve light-off performance and to have better thermal shock resistance than conventional honeycomb substrates to handle higher expected temperature gradients. Thermal shock resistance is generally evaluated on a substrate by evaluating the thermal strain caused by temperature gradients inside the substrate during durability testing [1,2]. During the test, a heated substrate is cooled at a surface face to generate temperature gradients while the temperature inside the honeycomb substrate is monitored by multiple thermocouples.

Today the Ammonia Selective Catalytic Reduction (SCR) system with good NOx conversion is the emission technology of choice for diesel engines globally. High NOx conversion SCR systems combined with optimized engine calibration not only address the stringent NOx emission limits which have been introduced or are being considered for later this decade, but also reduce CO2 emissions required by government regulations and the increase in fuel economy required by end-users. Reducing the packaging envelope of today's SCR systems, while retaining or improving NOx conversion and pressure drop, is a key customer demand. High SCR loadings ensure high NOx conversion at very low temperatures. To meet this performance requirement, a High Porosity Substrate which minimizes the pressure drop impact, was introduced in SAE Paper 2012-01-1079 [1], [2], [3].

To reduce friction is required to improve engine fuel economy. This study aimed to reduce piston skirt friction, which is a major factor in engine friction. ‘Soft skirt’ is a trendy item in recent gasoline engines, which can improve skirt sliding condition by larger deformation when the piston is pressed to the liner. The effect is confirmed by friction measurement and oil film observation, using prototype pistons. And also one major factor of the effect is clarified that not only side force but also cylinder pressure causes effective deformation of the skirt to create thick oil film at early combustion stroke.

Global environment protection, Co2 emission reduction and so on, is an important problem in automotive industry. An Electric Vehicle (EV) production is one of policies. Co2 emission of EV is lower than Internal Combustion Engine (ICE), petrol and diesel engine. On the other hand, customer's needs for the comfort on driving increase year after year. So it's an important factor for new car performance. Generally speaking, it's thought that the noise and vibration performance of EV have the better of ICE performance. However the aerodynamic noise and road noise contribution for interior noise in EV rise in comparison with ICE, and moreover the sound quality change by new noise component of the motor noise. Therefore new sound evaluation method is needed for EV. So this paper demonstrates each noise component contribution in EV by new noise separation technology, and show the comparison result with EV and ICE.

Mitsubishi Motors Corporation succeeded in mass production of the electric vehicle “i-MiEV” which features leading-edge technologies epitomized by lithium-ion battery. The EV was released into the Japanese market in July 2009 and the European market in January 2011. In order to be used all over the world, the EV has to be practical and durable even under severe weather of extremely cold or extremely hot regions. In this paper we report some results of the tests conducted under extremely cold weather as well as extremely hot weather. From the test results the validity of the vehicle control system and the practicality of the EV are verified.

An efficient cooling system will ensure the reliability of the EV/HEV (Electric Vehicle/Hybrid Electric Vehicle) battery system and extend their lifetime. In order to shorten design period or increase design iterations, a high-speed and high-precision prediction method for cooling is indispensable. For models, such as Mitsubishi i-MiEV, which use fresh air to cool batteries in the battery pack, a transient approach based on loosely coupled method is developed to predict temperature change of batteries. The results by our new approach are in good agreement with the experimental data. Moreover, for the EV/HEV using circulated air to cool its batteries, a second approach is also developed, which can predict the temperature variations of both EV/HEV batteries in the battery pack and the cooling air.

To evaluate various Diesel Particulate Filter (DPF) efficiently, accelerated tests are one of effective methods. In this study, a simulator composed by diesel fuel burners is proposed for fundamental DPF evaluations. Firstly particle size distribution measurement, chemical composition and thermal analysis were carried out for the particulate matter (PM) generated by the simulator with several combustion conditions. The PMs generated by specific conditions showed similar characteristics to PMs of a diesel engine. Through these investigations, mechanism of PM particle growth was discussed. Secondly diversified DPFs were subjected to accelerated pressure drop and filtration efficiency tests. Features of DPFs could be clarified by the accelerated tests. In addition, the correlation between DPF pressure drop performance and PM characteristics was discussed. Thirdly regeneration performance of the simulator's PM was investigated.

Following the previous reports, ventilation characteristics in automobile was investigated by using a half-scale car model which was created by the Society of Automotive Engineers of Japan (JSAE). In the present study, the ventilation mode of the cabin was foot mode which was the ventilation method for using in winter season. Supplied air was blown from the supply openings under the dashboard to the rear of the model via the driver's foot region in this mode. The experiment was performed in order to obtain accurate data about the airflow properties equipped with particle image velocimetry (PIV). Our experimental data is to be shared as a standard model to assess the environment within automobiles. The data is also for use in computational fluid dynamics (CFD) benchmark tests in the development of automobile air conditioning, which enables high accuracy prediction of the interior environment of automobiles.

The Inlet-Membrane DPF which has a small pore size membrane formed on the inlet side of the body wall has been developed as a next generation diesel particulate filter (DPF). It simultaneously realizes low pressure drop, small pressure drop hysteresis, high robustness and high filtration efficiency. The low pressure drop improves fuel economy. The small pressure drop hysteresis has the potential to extend the regeneration interval since the linear relationship between the pressure drop and accumulated soot mass improves the accuracy of the soot mass detection by means of the pressure drop values. The Inlet-Membrane DPF's high robustness also extends the regeneration interval resulting in improved fuel economy and a lower risk of oil dilution while its high filtration efficiency reduces PM emissions. The concept of the Inlet-Membrane DPF was confirmed using disc type filters in 2008 and its performances was evaluated using full block samples in 2009.

A newly developed small-sized IES (inductive energy storage) circuit with a semiconductor switch at turn-off action was successfully applied to an ignition system. This IES circuit can generate repetitive nanosecond pulse discharges. An ignition system using repetitive nanosecond pulse discharges was investigated as an alternative to conventional spark ignition systems in the previous papers. Experiments were conducted using constant volume chamber for CH₄ and C₃H₈-air mixtures. The ignition system using repetitive nanosecond pulse discharges was found to improve the inflammability of lean combustible mixtures, such as extended flammability limits, shorted ignition delay time, with increasing the number of pulses for CH₄ and C₃H₈-air mixtures under various conditions. The mechanisms for improving the inflammability were discussed and the effectiveness of IES circuit under EGR condition was also verified.

New systems or functionalities have been rapidly introduced for fuel economy improvement. Active vibration suppression has also been introduced. Control algorithm is required to be verified in real time environment to develop controller functionality in a short term. Required frequency domain property concept is proposed for representation of target phenomena with reduced models. It is shown how to select or reduce engine, transmission and vehicle model based on the concept. Engine torque profile which has harmonics of engine rotation is required for engine start, take-off from stand still, noise & vibration suppression and misfire detection for OBD simulation. An engine model which generates torque profile synchronous to crank angle was introduced and modified for real time simulation environment where load changes dynamically. Selected models and control algorithms were modified for real time environment and implemented into two linked universal controllers.

Spray-guided gasoline direct injection SI engines attract as one of new generation lean-burn engines to promise CO2 reduction. These typically adopt “narrow-spacing” concept in which an injector is centrally mounted close to a spark plug. Therefore, geometric targets of the fuel spray and a position of the spark plug have to be exactly limited to maintain a proper mixture in the spark gap. In addition, the stable combustion window is narrow because the spark ignition is limited in a short time during and immediately after the injection. These spatial and temporal restrictions involve some intractable problems concerning the combustion robustness due to the complicate phenomena around the spark plug. The local mixture preparation near the spark plug significantly depends on the spray-induced charge motion. The intense flow induced by the motion blows out and stretches the spark, thereby affecting the spark discharge performance.

This paper describes the calculative verification of the effect of the right-and-left torque vectoring system in various types of drivetrain, namely, the front wheels only, the rear wheels only, and both front and rear wheels in FWD, RWD, and AWD vehicles. The effect is evaluated by calculating the vehicle dynamics limit; maximum acceleration and cornering ability. The right-and-left vectoring torque, which is needed for expanding the vehicle dynamics limit, is also calculated. And finally, the paper evaluates the suitable wheels for which the system should be applied in each drivetrain. The application to the front wheels is more effective for FWD vehicles. On the other hand, the application to the rear wheels is more effective for RWD and AWD vehicles.

The development of diesel powered passenger cars is driven by the enhanced emission legislation. To fulfill the future emission limits there is a need for advanced aftertreatment devices. A comprehensive study was carried out focusing on the improvement of the DOC as one part of these systems, concerning high HC/CO conversion rates, low temperature light-off behaviour and high temperature aging stability, respectively. The first part of this study was published in [1]. Further evaluations using a high temperature DPF aging were carried out for the introduced systems. Again the substrate geometry and the catalytic coating were varied. The results from engine as well as vehicle tests show advantages in a highly systematic context by changing either geometrical or chemical factors. These results enable further improvement for the design of the exhaust system to pass the demanding emission legislation for high performance diesel powered passenger cars.

Thermal shock performance parameters to assure Ultra Thin Wall (UTW) substrate durability for close-coupled (CC) converter operating conditions have been defined through testing and FEM modeling. Propane burner tests simulating the engine exhaust conditions were performed and coordinated with FEM stress analysis. For the stress analysis, a newly developed Macro-Micro Thermal Stress Analysis method was employed. Validation of the Macro-Micro Thermal Stress Analysis method was made through comparing FEM analysis results with the electric furnace and the burner tests results. A thermal fatigue life prediction method taking into account variation in material strength, fatigue degradation and effective volume was developed. In the verification tests, crack generation stresses were predicted within a 20 % margin of error.