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In gasoline direct injection engines, fuel is injected into the port walls and the valve. During the engine startup cycle, the temperature of these parts is not adequate to evaporate all the fuel that impacts the walls. As a result, a fraction of the injected fuel does not contribute to the combustion cycle. This fraction forms fuel puddles (wall-wetting) and a portion of it passes to the crankcase. The efficiency of the engine during the startup cycle is decreased and hydrocarbon emissions increased. It is obvious that a control strategy is necessary to minimize the effects of this transient performance of the engine. This paper investigates a modeling framework for the valve, and simulation results validate model performance when compared to available experimental data. The simulation studies lead to a conceptual control design, which is briefly outlined.

A diesel engine can be modeled as a multiple-input, single output system, sometimes known as a coherence model. Theoretical models for multi-input, single output systems are quite well developed, but only recently have attempts been made to apply these models to practical noise cases such as diesel engines. The results of these models can be used to predict changes in engine noise as cylinder pressure - time history is varied or to attempt to identify sources of noise in the engine. Practical difficulties and simplifying assumptions which must be made are discussed.

The vibration transmission in engine structures has been studied to develop analytical models which predict changes in the noise related vibration of the engine as a function of design changes in the engine components. The models are based on vibration measurements made on non-running engines. This paper outlines the basic procedures for the necessary vibration measurements and for the development of the models. Two examples are given of models developed for different vibration transmission paths in different engines. The vibration transmission from the cylinder pressure to the engine block is modeled for a 4 cylinder DI diesel engine and compared with a simulated vibration transmission measurement with the engine not running. The vibration transmission from the engine block to covers and shields is modeled for a 6 cylinder in-line diesel and compared with the measured vibration transmission with the engine running.

Steering vibration is a major NVH issue that affects overall NVH comfort in passenger cars. There are two types of fundamental steering vibrations [1]: Vertical/lateral translational vibration Rotational vibration (Focus of this study) Many studies of mechanisms contributing to steering wheel nibble have been carried out in the past. An overview of stimulation sources (disturbance factors) to steering nibble like wheel imbalance mass is given. As an example of the controversial aspects of the problem, this paper deals with the assumption of suspension compliance characteristic and its conflict with the observed transfer of vibration caused by small (realistic) amounts of imbalance or tyre force variation. The tyre imbalance is virtually created by adding small mass on front right wheel. After modelling and correlating the full vehicle in ADAMS/car, it is possible to identify a natural frequency that contributes reasonably to the nibble phenomenon in the steering wheel.

Because of the increase of traffic on the highways in the last few years, retardation has become the most vital function of car operation; and safe retardation is as necessary as rapid retardation. Good brakes are as essential as a good engine. Becoming convinced of the many attendant advantages of four-wheel brakes, the authors began an intensive study of braking, the results of which are outlined. The features of construction of the Bendix-Perrot standardized four-wheel braking-system, which include: (a) standardized and improved controls, (b) standardized brakeshoes and (c) a simplified brake-operating layout or hook-up, are described and illustrated and the advantages to be obtained with these improvements are summarized.