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The efficiency of the NOx Storage and Reduction (NSR) catalysts used in the aftertreatment of diesel engine exhaust gases can potentially be increased by using reactive reductants such as CO and H₂ that are formed during in-cylinder combustion. In this study, a multi-dimensional computational fluid dynamics (CFD) code coupled with complex chemical analysis was used to study combustion with various fuel after-injection patterns. The results obtained will be useful in designing fuel injection strategies for the efficient formation of CO.

Until recently, the application of the detailed chemistry approach as a predictive tool for engine modeling has been sort of a “taboo” for different reasons, mainly because of an exaggerated rigor to the chemistry/turbulence interaction modeling. In terms of this ideology, if the interaction cannot be simulated properly, the detailed chemistry approach makes no sense. The novelty of the proposed methodology is the coupling of a generalized partially stirred reactor, PaSR, model with the high efficiency numerics to treat detailed oxidation kinetics of hydrocarbon fuels. In terms of this approach, chemical processes are assumed to proceed in two successive steps: the reaction follows after the micro-mixing is completed on a sub-grid scale.

An investigation of the possibility to extend the 3-dimensional modeling capabilities from conventional diesel to the HCCI combustion mode simulation was carried out. Experimental data was taken from a single cylinder engine operating with early injections for the HCCI and a split-injection (early pilot+main) for the high speed Diesel engine operation. To properly phase the HCCI mode in the experiments, high amounts of cooled EGR and a decreased compression ratio were used. In numerical simulation performed using KIVA3-V code, modified to incorporate the Detailed Chemistry Approach the same conditions were reproduced. Special attention is paid on the analysis of the events leading up to the auto-ignition, which was reasonably well predicted.

48V mild hybrid powertrains are promising technologies for cost-effective compliance with future CO2 emissions standards. Current 48V powertrains with integrated belt starter generators (P0) with downsized engines achieve CO2 emissions of 95 g/km in the NEDC. However, to reach 75 g/km, it may be necessary to combine new 48V powertrain architectures with alternative fuels. Therefore, this paper compares CO2 emissions from different 48V powertrain architectures (P0, P1, P2, P3) with different electric power levels under various driving cycles (NEDC, WLTC, and RTS95). A numerical model of a compact class passenger car with a 48V powertrain was created and experimental fuel consumption maps for engines running on different fuels (gasoline, Diesel, E85, CNG) were used to simulate its CO2 emissions. The simulation results were analysed to determine why specific powertrain combinations were more efficient under certain driving conditions.

An advanced catalytic exhaust after-treatment system addresses the problem of NOX emissions from heavy-duty diesel trucks, relying on real-time catalyst modelling. The system consists of de-NOX catalysts, a device for injection of a reducing agent (diesel fuel) upstream the catalysts, and computer programmes to control the injection of the reducing agent and to model the engine and catalysts in real time. Experiments with 5 different air-assisted injectors were performed to determine the effect of injector design on the distribution of the injected diesel in the exhaust gas stream. A two-injector set-up was investigated to determine whether system efficiency could be increased without increasing the amount of catalyst or the amount of reducing agent necessary for the desired outcome. The results were verified by performing European standard transient cycle tests as well as stationary tests.

Combustion with knock is an abnormal phenomenon which constrains the engine performance, thermal efficiency and longevity. The advance timing of the ignition system requires it to be updated with respect to fuel octane number variation. The production series engines are calibrated by the manufacturer to run with a special fuel octane number. In the experiment, the engine was operated at different speeds, loads, spark advance timings and consumed commercial gasoline with research octane numbers (RON) 95, 97 and 100. A 1-dimensional validated engine combustion model was run in the GT-Power software to simulate the engine conditions required to define the knock envelope at the same engine operation conditions as experiment. The knock intensity investigation due to spark advance sweep shows that combustion with noise was started after a specific advance ignition timing and the audible knock occur by increasing the advance timing.

Heavy alcohols can be mixed with fossil diesel to produce blended fuels that can be used in diesel engines. Alcohols can be obtained from fossil resources, but can also be produced more sustainably from renewable raw materials. The use of such biofuels can help to reduce greenhouse gas (GHG) emissions from the transport sector. This study examines four alcohol/diesel blends each containing one heavy alcohol: n-butanol, iso-butanol, 2-ethyl hexanol and n-octanol. All of the blends where prepared to function as drop-in fuels in existing engines with factory settings. To compensate for the alcohols′ low cetane numbers (CN), a third component with high CN was added to each blend, namely hydrotreated vegetable oil (HVO). The composition of each mixture was selected to give an overall CN equal to that of fossil diesel fuel.

The purpose of this paper is to outline a new computer controlled transfer for four-wheel drive vehicles, which AISIN-WARNER LIMITED of Japan has developed in cooperation with TOYOTA MOTOR CORPORATION. Certain difficulties still remain with shafting of a conventional transfer. Coupled with a 4-speed automatic transmission, the new transfer discussed in this paper consists of 3 wet clutches, a simple planetary gear set, a chain for front drive and a control unit. This transmission-transfer combination (30-80LE) has realized “ON THE GO SHIFT” for easier operations of the 4WD applications.

The three-way-catalyst (TWC) is an essential part of the exhaust aftertreatment system in spark-ignited powertrains, converting nearly all toxic emissions to harmless gasses. The TWC’s conversion efficiency is significantly temperature-dependent, and cold-starts can be the dominating source of emissions for vehicles with frequent start/stops (e.g. hybrid vehicles). In this paper we develop a thermal TWC model and calibrate it with experimental data. Due to the few number of state variables the model is well suited for fast offline simulation as well as subsequent on-line control, for instance using non-linear state-feedback or explicit MPC. Using the model could allow an on-line controller to more optimally adjust the engine ignition timing, the power in an electric catalyst pre-heater, and/or the power split ratio in a hybrid vehicle when the catalyst is not completely hot.

A common fan model to use in automotive under hood simulations is the Multiple Reference Frame (MRF) model and within the industry, for this specific application, this model is well known to under predict performance. In this paper we have examined the possibilities of correcting this deficiency with a simple “speed correction”. This is done by testing and simulating a production fan in the Volvo Fan Test Rig for two operating speeds, 1200 rpm and 2400 rpm. Pressure rise, fan power and static efficiency are presented as functions of volumetric flow rate. The simulations verify that using the MRF model the common behavior of under predicting pressure rise and performance of the fan occur. In addition, this work shows that; although the MRF is not predicting fan performance correctly it constitutes a reliable fan modeling strategy.

A diesel engine model, designed for studying events during automated gear shifting in a heavy duty truck is presented. It will be used for developing and evaluating powertrain control strategies. The deceleration in engine speed to the new synchronous speed, during an upshift, is of special intereset. The straightforward approach is to cut fuel and wait for the engine to slow down due to friction and pumping losses. In many cases, this approach is too slow, and the engine compression brake needs to be activated. The engine model, assuming quasi-steady, bidirectional thermodynamic flow with constant specific heat capacities, is implemented using Modelica. A simple model of the hydraulic circuit that governs the activation of the compression brake mode is incorporated in the model. Problems related to the simulation of the engine brake systems are discussed. They are handled by empirical correction factors. Measurements from rapid engine speed decelerations are used for verification.

By developing a mechanical-firing sensor using rotational inertia effect, we have completed miniaturization of the sensor and have developed a new-type mechanical-firing airbag system. This airbag system has been confirmed to have superior occupant protection performance after conducting a variety of vehicle crash tests and sled tests.

A single cylinder, naturally aspirated, four-stroke and camless (Otto) engine was operated in homogeneous charge compression ignition (HCCI) mode with commercial gasoline. The valve timing could be adjusted during engine operation, which made it possible to optimize the HCCI engine operation for different speed and load points in the part-load regime of a 5-cylinder 2.4 liter engine. Several tests were made with differing combinations of speed and load conditions, while varying the valve timing and the inlet manifold air pressure. Starting with conventional SI combustion, the negative valve overlap was increased until HCCI combustion was obtained. Then the influences of the equivalence ratio and the exhaust valve opening were investigated. With the engine operating on HCCI combustion, unthrottled and without preheating, the exhaust valve opening, the exhaust valve closing and the intake valve closing were optimized next.

A very difficult problem exists regarding windshield shape, and that is to create a balance between aerodynamics and optical distortion. To assist in solving this problem, this study, concerning the characteristics of visual perception for the optical distortion when drivers receive visual information through a windshield, was carried out. In this study, the windshield area was divided into 4 zones from the viewpoints of the level of drivers' fixation frequency and types of objects observed. Distortion was defined as the gap angle ( distortion angle ), which crossed the lines of a grid board with and without a windshield, and distortion angles were measured on a total of 4 windshields. Four drivers indicated areas in each windshield in which they felt the area was distorted. As a result, the thresholds of optical distortion were shown as a function of the horizontal and vertical distortion angles by discriminatory analysis.

The authors developed a low-speed in-vehicle network for the body control system on passenger cars, where the most remarkable effects to reduce the number of wire harnesses could be expected. First, the authors analyzed the body control system to clarify the specifications required to build a low-speed in-vehicle network. Then the authors worked out optimum communication protocol, placing emphasis on cost reduction which is the key to expanding the applications of the low-speed in-vehicle network over wider fields. The low-speed in-vehicle network was evaluated for its performance through simulation and on-vehicle tests, and proved the practical validity of the concept. It was also verified that introducing the low-speed in-vehicle network has a satisfactory effect to reduce the number of wire harnesses.

In order to correspond to the exhaust emissions regulations that become severe every year, more advanced engine control becomes necessary. Engine engineers are concerned about the Hydrocarbons (HCs) that flow through the air-intake ports and that are difficult to precisely control. The main sources of the HCs are, the canister purge, PCV, back-flow gas through the intake valves, and Air / Fuel ratio (A/F) may be aggravated when they flow into the combustion chambers. The influences HCs give on the A/F may also grow even greater, which is due to the increasingly stringent EVAP emission regulations, by more effective ventilation in the crankcase, and also by the growth of the VVT-operated angle and timing, respectively. In order to control the A/F more correctly, it is important to estimate the amount of HCs that are difficult to manage, and seek for suitable controls over fuel injection and so on.

The compression ratio is an important engine design parameter. It determines to a large extend engine properties like the achievable efficiency, the heat losses from the combustion chamber and the exhaust losses. The same properties are affected by insulation of the combustion chamber. It is therefore especially important to know the compression ratio when doing experiments with thermal barrier coatings (TBC). In case of porous TBCs, the standard methods to measure the compression ratio can give wrong results. When measuring the compression ratio by volume, using a liquid, it is uncertain if the liquid fills the total porous volume of the coating. And for a thermodynamic compression ratio estimation, a model for the heat losses is needed, which is not available when doing experiments with insulation. The subject of this paper is the evaluation of an alternative method to assess the compression ratio.

An engine model for use in computer simulation of transient behavior in drivetrain and vehicle systems is presented. Two elements, important for deviation (e.g. turbo-lag) from steady state characteristics, are the inertia of the supercharging unit (turbo shaft) and the fuel injection control system. No extensive combustion calculations are carried out within the model. Instead it uses condensed results from existing combustion models and measurements. The model is semi-empirical. Some of the engine specific properties needed for simulation are (e.g. for a turbocharged diesel): engine data in steady state operation, mappings of compressor and turbine performance, inertia of the engine components condensed to the crankshaft, turbo shaft inertia, displacement, compression ratio and the essentials of the fuel injection control strategy. Input parameters to the computer program based on the model are accelerator pedal position and external torque acting on the flywheel.

A multi-dimensional numerical method for predicting the warm-up characteristic of automobile catalytic converter systems was developed to effectively design catalytic converter systems which achieve low tail pipe emissions with satisfactory packagebility. The features of the method are; (1) consideration of the governing phenomena such as gas flow, heat transfer, and chemical reactions (2) capability of predicting warm-up characteristic for not only the catalytic converters but also the system as a whole during emission test modes such as the USA LA-4 mode. The description of the method is presented. The experimental verifications of the method were conducted to assure the accuracy of it. The effect of design parameters such as electrically heated catalyst (EHC), high loading of noble metal and thin honeycomb wall on warm-up characteristic of the catalyst are analyzed in the paper.

In the field of automotive body electronic control such as control of door locks, power windows, and wipers, there is a growing need of multiplexing communication to reduce the amount of wire harnesses. To meet this need, we developed a multiplexing communication protocol particularly suited to the body electronic control. Based on the developed protocol, we designed a communication control IC and a simple driver/receiver circuit with a few discrete components. The bus access method of the communication is the CSMA/CD with nondestructive bit arbitration, and its bit rate is 5 kbps. Its transmission media is a single wire. The communication IC has a multiplexing control block and a serial I/O block for an interface with a host CPU. It was fabricated using CMOS technology and has a chip of 2.6mm x 3.0mm in size that contains about 5,000 transistors. The driver/receiver circuit consists of one transistor, one capacitor and several resistors.