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A mean value turbocharged engine model is useful in terms of accuracy and convenience for fuel economy strategies or engine controller development. Turbocharging process is a feedback system with a positive gain, i.e. increasing exhaust work leads to increasing a cycle work. The gain of the feedback system is determined mainly by exhaust work ratio in a cycle and inertia of the turbine. The work ratio was investigated based on engine test with EGR. A turbocharging process model was obtained using the work ratio in a cycle and theoretical equations. The model is applied to investigate manifold absolute pressure response with EGR.

Gasoline engines have the trace-knock phenomena induced by the fast combustion which happens a few times during 100 cycles. And that constrains the thermal efficiency improvement due to limiting the ignition timing advance. So the authors have been dedicating a trace-knock simulation so that we could obtain any pieces of information associated with trace-knock characteristics. This simulation consists of a turbulent combustion model, a cycle-by-cycle variation model and a chemical calculation subprogram. In the combustion model, a combustion zone is considered in order to obtain proper turbulent combustion speed through wide range of engine speed. From a cycle-by-cycle variation analysis of an actual gasoline engine, some trace-knock features were detected, and they were involved in the cycle-by-cycle variation model. And a reduced elementary reaction model of gasoline PRF (primary reference fuel) was customized to the knocking prediction, and it was used in the chemical calculation.

The automotive refrigerant system can occasionally exhibit an excessive noise out of air-conditioner (A/C) vents during vehicle’s developments. If the vehicle has been parked for long hours in summer and the A/C system is turned on, sometimes hissing noise is induced by the refrigerant flow. In order to understand the mechanism, a lot of bench and vehicle tests were conducted. However, there is still not enough to understand the physical behavior in detail. Therefore, for the first step, the visualization method to capture the behavior of multi-phased refrigerant flow jet inside the pipe was proposed with a high-speed camera, some light devices and acrylic test piece. In addition, image analysis to quantify the flow regime from a series of observed snapshots. Using proposed method, the correlation study between flow and noise was performed at A/C bench test. As a result, different flow features such as the velocity can be observed in the occurrence of the noise or not.

Improving fuel efficiency often affects NVH performance. Modifying a vehicle’s design in the latter stages of development to improve NVH performance is often costly. Therefore, to optimize the cost performance, a Multi-Attribute Balancing (MAB) approach should be employed in the early design phases. This paper proposes a solution based on a unified 1D system simulation model across different vehicle performance areas. In the scope of this paper the following attributes are studied: Fuel economy, Booming, Idle, Engine start and Drivability. The challenges to be solved by 1D simulation are the vehicle performance predictions, taking into account the computation time and accuracy. Early phase studies require a large number of scenarios to evaluate multiple possible parameter combinations employing a multi-attribute approach with a systematic tool to ease setup and evaluation according to the determined performance metrics.

For higher mileage vehicles, noise from contaminant ingress is one of the largest durability issues for wheel bearings. The mileage that wheel bearing sealing issues increase can vary due to multiple factors, such as the level of corrosion for the vehicle and the mating components around the wheel bearing. In general, sealing issues increase after 20,000 to 30,000 km. Protecting the seals from splash is a key step in extending bearing life. Benchmarking has shown a variety of different brake corner designs to protect the bearing from splash. This report examines the effect of factors from different designs, such as the radial gap between constant velocity joint (CVJ) slinger and the knuckle, knuckle labyrinth height and varying slinger designs to minimize the amount of splash to the bearing inboard seal. This report reviews some of the bearing seal failure modes caused by splash.

The strong focus on reducing brake drag, driven by a historic ramp-up in global fuel economy and carbon emissions standards, has led to renewed research on brake caliper drag behaviors and how to measure them. However, with the increased knowledge of the range of drag behaviors that a caliper can exhibit comes a particularly vexing problem - how should this complex range of behaviors be represented in the overall road load of the vehicle? What conditions are encountered during coastdown and fuel economy testing, and how should brake drag be measured and represented in these conditions? With the Environmental Protection Agency (amongst other regulating agencies around the world) conducting audit testing, and the requirement that published road load values be repeatable within a specified range during these audits, the importance of answering these questions accurately is elevated. This paper studies these questions, and even offers methodology for addressing them.

Without engine noise, the cabin of an electric vehicle is quiet, but on the other hand, it becomes easy to perceive refrigerant-induced noise in the automotive air-conditioning (A/C) system. When determining the A/C system at the design stage, it is crucial to verify whether refrigerant-induced noise occurs in the system or not before the real A/C systems are made. If refrigerant-induced noise almost never occurs during the design stage, it is difficult to evaluate by vehicle testing at the development stage. This paper presents a 1D modeling methodology for the assessment of refrigerant-induced noise such as self-excitation noise generated by pressure pulsation through the thermal expansion valve (TXV). The GT-SUITE commercial code was used to develop a refrigerant cycle model consisting of a compressor, condenser, evaporator, TXV and the connecting pipe network.

Recently, the evaluation of the thermal environment of an engine compartment has become more difficult because of the increased employment and installation of turbochargers. This paper proposes a new prediction model of the momentum source for the turbine of a turbocharger, which is applicable to three-dimensional thermal fluid analyses of vehicle exhaust systems during the actual vehicle development phase. Taking the computational cost into account, the fluid force given by the turbine blades is imitated by adding an external source term to the Navier-Stokes equations corresponding to the optional domain without the computational grids of the actual blades. The mass flow rate through the turbine, blade angle, and number of blade revolutions are used as input data, and then the source is calculated to satisfy the law of the conservation of angular momentum.

Torque profile control is one of required technologies for propulsion engines. A smaller parametric model is more preferable for control algorithm design and evaluation. Mean value engine torque can be obtained from throttle opening change using a transfer function. A transfer function for a turbocharged engine was investigated with thermo-dynamic equations for a turbine and a compressor and test data. A small turbocharged engine was tested to model the air transfer process. Turbine speed was measured with temperatures, pressures and air mass flow. Turbine speed response is like a first order system to air mass flow into a combustion chamber. The pressure ratio at the compressor is approximated by a curve proportional to the turbine speed square. Based on those findings, a reduced order model for describing dynamic air transfer process with a turbocharger was constructed. The proposed model is compact and suitable for engine torque control design and controller implementation.

Downsizing engines with a turbocharging system have been widely applied to passenger cars to improve fuel economy. Engine torque response to accelerator operation is one of important features in addition to steady state performance of the system. Torque profile management for turbocharged internal combustion engines is one of required technologies. A turbocharging system for a car is a system with a positive feedback loop in which compressed air drives the compressor after the combustion process. A reduced order model was derived for the charging system. Pressure ratio of a compressor is proportional to square of turbine speed and the turbine speed is a first order delay system to throttle opening in the model. Model structure was designed from mathematical equations that describe turbine and compressor works. Model parameters were identified from measured data. An output torque profile control strategy based on the derived model is investigated.

A KIVA code which is customized for passenger car's diesel engines is linked with an engine performance simulator and demonstrated with our optimizing calculation system. Aiming to fulfill our target calculation speed, the combustion model of the KIVA code is changed from a chemical reaction calculation method to a chemical equilibrium calculation method which is introduced a unique technique handling chemical species maps. Those maps contain equilibrium mole fraction data of chemical species according to equivalence ratio and temperature. Linking the KIVA code to the engine simulator helps to evaluate engine performance by indicated mean effective pressure (IMEP). The optimizing calculation system enables to obtain response surfaces. Observing the response surfaces, clear views of engine performance characteristics can be seen. The overview of this calculation system and some examples of the calculation are shown in this paper.

Compression ratio of newly developed gasoline engines has been increased in order to improve fuel efficiency. But in-cylinder pressure around top dead center (TDC) before spark ignition timing is higher than expectation, because the low temperature oxidization (LTO) generates some heat. The overview of introduced calculation method taking account of the LTO heat of unburned gas, how in-cylinder pressure is revised and some knowledge of knocking prediction using chemical kinetics are shown in this paper.

The human thermal comfort, which has been a subject of extensive research, is a principal objective of the automotive climate control system. Applying the results of research studies to the practical problems require quantitative information of the thermal environment in the passenger compartment of a vehicle. The exposure to solar radiation is known to alter the thermal environment in the passenger compartment. A photovoltaic-cell based sensor is commonly used in the automotive climate control system to measure the solar radiation exposure of the passenger compartment of a vehicle. The erroneous information from a sensor however can cause thermal discomfort to the occupants. The erroneous measurement can be due to physical or environmental parameters. Shading of a solar sensor due to the opaque vehicle body elements is one such environmental parameter that is known to give incorrect measurement.

The vehicle air-conditioning system has significant impact on fuel economy and range of electric vehicles. Improving the fuel economy of vehicles therefore demand for energy efficient climate control systems. Also the emissions regulations motivate the reduced use of fuel for vehicle's cabin climate control. Solar heat gain of the passenger compartment by greenhouse effect is generally treated as the peak thermal load of the climate control system. Although the use of advanced glazing is considered first to reduce solar heat gain other means such as ventilation of parked car and recirculation of cabin air also have impetus for reducing the climate control loads.

To research the mechanism of automobile aerodynamic noise which transmits to the inside of a cabin, flow structure and sound field have been investigated by applying experimental measurements at the wind tunnel and computational fluid dynamics (CFD) based on lattice Boltzmann method (LBM). In this research, transmitted noise at a front side window glass is focused. Pressure fluctuations on the side window glass contain both hydrodynamic pressure fluctuations induced by convection of flow field and acoustic pressure fluctuations propagated from noise sources. But it was found that acoustic pressure fluctuations have large contributions on the side window glass at the high frequency range by considering of the experimental transmission loss. On the other hand, at the low frequency range, hydrodynamic pressure fluctuations are dominant, however their effects to transmitted noise are not so influential for high fluctuation levels.

Global environmental and economic concerns regarding increasing fuel consumption and greenhouse gas emission are driving changes to legislative regulations and consumer demand. As regulations become more stringent, advanced engine technologies must be developed and implemented to realize desired benefits. Discrete variable valve lift technology is a targeted means to achieve improved fuel economy in gasoline engines. By limiting intake air flow with an engine valve, as opposed to standard throttling, road-load pumping losses are reduced resulting in improved fuel economy. This paper focuses on the design and development of a switching roller finger follower system which enables two mode discrete variable valve lift on end pivot roller finger follower valvetrains. The system configuration presented includes a four-cylinder passenger car engine with an electro-hydraulic oil control valve, dual feed hydraulic lash adjuster, and switching roller finger follower.

An advanced variable valve actuation (VVA) system is characterized following end-of-life testing to enable fuel economy solutions for passenger car applications. The system consists of a switching roller finger follower (SRFF) combined with a dual feed hydraulic lash adjuster and an oil control valve that are integrated into a four cylinder gasoline engine. The SRFF provides discrete valve lift capability on the intake valves. The motivation for designing this type of VVA system is targeted to improve fuel economy by reducing the air pumping losses during part load engine operation. This paper addresses the durability of a SRFF for meeting passenger car durability requirements. Extensive durability tests were conducted for high speed, low speed, switching, and cold start operation. High engine speed test results show stable valvetrain dynamics above 7000 engine rpm. System wear requirements met end-of-life criteria for the switching, sliding, rolling and torsion spring interfaces.

Accuracy of numerical simulation has to be evaluated through the actual phenomenon such as experiment or measurement and then it can be employed to design the air-conditioning system of car cabin at the development phase. Scaled model of vehicle cabin was created by the Society of Automotive Engineers of Japan (JSAE) and the experiment was performed to obtain the detailed information of heat transfer characteristics inside the cabin under the non-isothermal condition. The sheet heaters were put to the inner surface of the acrylic cabin and they supplied certain amount of heat. The temperatures of inner and outer surface and air were measured to evaluate the thermal environment of the cabin. The results lead to enhancement of the data of the standard model of the cabin.

Automotive fenders is one such example where specialized thermoplastic material Noryl GTX* (blend of Polyphenyleneoxide (PPO) + Polyamide (PA)) has successfully replaced metal by meeting functional requirements. The evolution of a fender design to fulfill these requirements is often obtained through a combination of unique material properties and predictive engineering backed design process that accounts for fender behavior during the various phases of its lifecycle. This paper gives an overview of the collaborative design process between Mitsubishi Motors Corporation and SABIC Innovative Plastics and the role of predictive engineering in the evolution of a thermoplastic fender design of Mitsubishi Motors Corporation's compact SUV RVR fender launched recently. While significant predictive work was done on manufacturing and use stage design aspects, the focus of this paper is the design work related to identifying support configuration during the paint bake cycle.

Driving car means to control a vehicle according to a target path, e.g. road and speed, with some constraints. Human driving models have been proposed and applied for simulations. However, human control in driving has not been analyzed sufficiently comparing with that of machine control system in term of control theory. Input - output property with internal information processing is not easily measured and described. Response of human driving is not as quicker as that of machine controller but human can learn vehicle response to driving operation and predict target changes. Driving behavior of an expert driver and a beginner in an emission test cycle was measured and difference in target speed tracking was looked into with performance indices. The beginner's operation was less stable than that of the expert. Transfer function of the vehicle system was derived based on linearized model to investigate human driving behavior as a tracking controller in the system.