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CHEVROLET has made its new air-suspension system easily interchangeable in production line assembly with standard full-coil suspension by adopting a 4-link-type rear suspension with short and long arms. A feature of the system is the mounting of the leveling valves within the air-spring assemblies. These valves correct riding height continually at a moderate rate, regardless of whether the springs are leveling or operating in ride motion. The system provides constant frequency ride—ride comfort remains the same whether the car is occupied by the driver alone or is fully loaded.

The environment is one of the most important issues currently facing the world and the automobile industry is required to respond with eco-cars. To meet this requirement, the hybrid vehicle is one of the most optimal solutions. The hybrid system automatically stops engine idling (idling stop), or stops the engine during deceleration to recover energy. The engine stop however creates a problem concerning the vehicle's climate control system. Because the conventional climate control system incorporates a compressor driven by engine belt, there is almost no cooling performance while the engine is stopped. Until now, when a driver needed more cooling comfort the engine has been switched back on as a compromise measure. To realize cabin comfort that is consistent with fuel saving, a 2-way driven compressor has been developed that can be driven both by engine belt while the engine is running and by electric motor when the engine is stopped.

The demands for comfort and a cleaner environment have been increasing for the past years for motorcycle as well as car manufacturers. With the need to decrease the time-to-market, there is a clear drive to apply CAE-based methods in order to evaluate new designs and to propose design changes that solve any identified problems. More specifically, the demands on the comfort of the rider are not only related to ride & handling and vibration levels(1), but also to the noise levels generated by the motorcycle. This paper presents the virtual modeling of one-cylinder engine of a motorcycle that identifies the mechanism behind the generation of an annoying noise. Furthermore, different possible design changes were evaluated in order to solve the problem. A combined experimental and numerical approach was followed to achieve this. Experiments were used to identify important parameters that determine the engine behavior and thus are critical for the modeling of such an engine.

In order to improve the fit and comfort of helmets, we developed digital head models that represent the anthropometric and morphometric variability found in the U.S. Navy. We analyzed the size and shape variation using two related approaches. First, we used Procrustes superimposition, which minimizes the distances between all landmarks of all subjects. This allowed us to visualize the variation in landmark distribution of the face and to test for statistical differences. Second, we extracted curvatures along the surface of the head. This allowed us to characterize the variation in the shape of the head. To create a series of sized digital models, we used principal component analysis (PCA) to organize the variation in both the traditional measurements as well as the locations of the 3D landmarks. Using an adaptation of multivariate accommodation modeling we identified representative individuals who characterize 95% of the variation in size and shape.

The vehicle Heating, Ventilation and Air conditioning (HVAC) system is designed to meet both the safety and thermal comfort requirements of the passengers inside the cabin. The thermal comfort requirement, however, is highly subjective and is usually met objectively by carrying out time dependent mapping of parameters like the velocity and temperature at various in-cabin locations. These target parameters are simulated for the vehicle interior for a case of hot soaking and its subsequent cool-down to test the efficacy of the AC system. Typically, AC performance is judged by air temperature at passenger locations, thermal comfort estimation along with time to reach comfortable condition for human. Simulating long transient vehicle cabin for thermal comfort evaluation is computationally expensive and involves complex cabin material modelling.

Today's agri-businessman is challenged to improve his efficiency to meet higher operating costs and to counter the effects of inflation. New concepts in John Deere's line of 4-wheel-drive tractors are targeted toward this goal and provide increased productivity through power increases, improved fuel economy, comfortable convenient operator environment and controls, increased hydraulic power, improved serviceability and repairability and monitoring of more critical vehicle functions.

Electrical Air Conditioning Systems for 42 V vehicles will provide many benefits in terms of Environment protection, car Architecture, cabin Comfort and overall Safety. E-A/C Systems essentially differ from conventional ones by the use of electrical compressors. First of all, they will be particularly well adapted to new powertrains, helping to make them more environmentally friendly. Accurate control and high efficiency under the most common thermal conditions will reduce the A/C impact on fuel consumption. Besides, higher sealing integrity will cut emissions of refrigerant during normal operation and maintenance. Secondly, the use of an electrically driven compressor (EDC) will suppress a belt, and will reduce the packaging constraints. This will help to design new vehicle architectures. Thirdly, the electrification of air conditioning will allow better thermal comfort. In particular, E-A/C Systems provide a good opportunity for cabin pre-conditioning.

A new compact skid steer loader has been developed. Along with productivity and cost, the design of this loader was concentrated on improving ease of operation, operator comfort and safety, and serviceability. This paper discusses how serviceability was improved over previous model Bobcats. That is; improved accessibility to regulary serviced items, reduced service parts and improved reliability.

Weight reduction and high transmission efficiency demands are getting heavier to manual transmission (MT) for vehicle driving and fuel economy performance. Also comfortable shift feeling and low gear noise level are continuously required by customer because those sensitivity performances are directly recognized by driver which can determine the transmission's merchantability. Newly developed high torque capacity MT is based on serial transmission BG6 which is adopted into a lot of customer' vehicle. This new MT is weight reduced, shift feeling and gear noise performance are highly improved that keeps strong competitiveness in the future. Concerning shift feeling, its smoothness, force balance and cross shift performance are improved and optimized. Also for low gear noise performance, it was reduced to the level which can have advantage to competitor and highly comfortable for passenger vehicle. Those improvement technologies are reported as follows.

This paper gives a report on ergonomic approaches we tried to scooters for improvements in their riding comfort. First we conducted investigations into riding postures that offer a comfortable scooter ride. That is, we picked out major items for the evaluation of scooter riding postures and investigated a correlation between those items and their physical quantities. Our investigation revealed that room for leg and arm movements played a major role in a scooter riding posture. We further found out a high correlation between the evaluation items for legroom and the knee angles and also high correlation between the evaluation items for legroom and the ankle angle. Next we report on the result of the attempt we made at improved riding comfort by equipping the scooter seat with a backrest. To check the effects of backrest, we measured the seating pressure distribution, myogenic potential, and cardiogenic potential.

The automobile body industry in Indonesia is developed by the needs of motorized means of transportation, especially for passengers cheap enough to meet the consumer's buying power. To fill these needs, modifications on commercial vehicles into passenger vehicles or provisions for passenger space on special chassis had been carried out. It can be seen that basically body construction or modification in the automobile body industry is but an extension of the automobile industry in general. At present, commercial vehicles are designed to run with higher speeds and lower fuel consumption. This situation calls for a structure design that has to meet specifications generally applied to automobiles, so as to enable it to perform equally well with the basic vehicles.

In this paper the first results of a project, initiated in the University of Coimbra and dealing with the conjugated influence of multiple stressors in riding passengers, are presented. A field study was conducted in public transportation buses, in which the subjective response of the occupants was collected and the physical parameters related to thermal comfort, air quality, vibration and noise were acquired. More than 250 responses to a subjective inquire were collected. Besides questioning the occupants about how they felt the different stressors, the questionnaires also have a final question related to how they felt the global comfort of the vehicle, in a five-point scale. Even if it looks too far, the final goal of this project is to obtain an general comfort index that takes into account the influence of multiple stressors, thus giving to vehicle manufacturers a tool to evaluate the performance of their models and to improve the vehicle friendliness to passengers.

Vehicle Dynamics testing has its importance in the fields of benchmarking and the validation of mathematical models built in order to predict the ride performance of the vehicle. The importance of enhancing the ride comfort is increasing day by day in present day scenario because of the long hours of driving experience. In presented work, the ride testing is done for two hatchback vehicles on highway conditions in order to compare the ride quality and ride comfort. The parameters like Vibration Dose Value, SEAT factor and Ride Diagram values are used to evaluate the ride comfort. After successful evaluation of the vibration levels affecting the ride comfort of the driver as well as the passenger the next major task is to identify and study the cause of the discomfort. The cause of the discomfort is studied and analyzed in terms of the complex motion of the vehicle. Vehicle motions like choppiness produces higher levels of discomfort as compared to the vertical movement of the vehicle.

In order to specify the human dynamic comfort of seat vibration, a lot of work has been conducted in laboratory research. From the seating manufacturer's perspective, the author proposed a test method to measure the seat ride comfort by using a spring-mass dummy which was designed to match the human response in low frequency in vertical direction. A hydraulic table was employed as the excitation source to the occupied seat. Two seat samples, both measured with human occupants before, were used for this study. For simplicity and comparison, a sweep sine signal in vertical direction was used as the excitation signal. The transmissibility results measured of the dummy loaded seat were compared to those of human occupants. In this paper, a continuing effort focused on correlating the vibration response from dummy occupied seat to that from human occupied seat. A consistent relation was shown between the two measurements.

Accurate assessment of thermal comfort requires comprehensive analysis of the environmental effects contributing to the heat transfer to and from the human body. A common comfort evaluation approach (e.g. PMV/PPD, Equivalent Temperature) is to find a direct correlation of comfort to environmental conditions (e.g. air temperature, relative humidity, clothing), thus implicitly accounting for the relationship between physiological response and thermal comfort. An alternate approach (e.g. Berkeley Comfort Model, Fiala's DTS) is to explicitly correlate comfort to basic physiological response (e.g. skin and core temperature), thereby separating the thermal analysis portion of the problem from the more subjective comfort analysis portion. While it has been shown that comparable results can be obtained between environment-based comfort metrics and physiology-based comfort metrics, the latter should be employed for optimal prediction accuracy.

Experience tells us that one can develop a technically comfortable seat where the seat fits and supports the occupant. The pressure distribution is optimized and the seat and packaging are such that a good posture is attainable by many. The dynamic characteristics of the seat and the vehicle are technically good. Despite all this the customer is not satisfied. Despite it being a technically comfortable seat, it does meet the customers' expectations and/or priorities and thus the comfort provided is lacking. This paper seeks to explore that gap between the seat and the user by modeling comfort using techniques similar to those found in the social sciences where models often focus on user or individual behavior. The model is built upon but diverges from the Cobb Douglas consumer utility model found in economics. It is presented as theory and presents a very different perspective on comfort.

Transmission of vibration and noise to the occupants and especially driver contributes significantly to the quality perception of the motor vehicle and eventually, it affects the overall ride comfort. These forces mainly reach to customer through tactile locations, i.e. floor, gearshift lever, steering wheel and seat. Showroom/Parking customer drive pattern of a vehicle evinces the steering system and driver’s seat rail vibration as strikingly linked aspect to evaluate human comfort [1]. This paper deals with the study of vibration at steering wheel and seat affecting human comfort at engine idle rpm with AC ON and OFF condition for passenger vehicles. The transmissibility of engine and radiator induced vibrations has been investigated with respect to modal alignment of steering and seat system.

Impact torque will be generated on the steering wheel when one tire suddenly blows out on high way, which may cause driver's psychological stress and result in driver's certain misoperations on the car. In this paper, the model of tire blowout vehicle was established; the tire blowout was detected based on the change rate of tire pressure, meanwhile, the rack force caused by tire blowout was estimated through a reduce observer; finally the compensation current was figured out to reduce the impact torque on the steering wheel. Results of simulation tests showed that the control strategy proposed in this paper can effectively reduce the impact torque on the steering wheel and reduce the driver's discomfort caused by tire blowout.

This paper proposes a new evaluation method of analyzing stability and design of a controller for an electric power steering (EPS) system. The main purpose of the EPS system’s control design is to ensure a comfortable driving experience of drivers, which mainly depends on the assist torque map. However, the high level of assist gain and its nonlinearity may cause oscillation, divergence and instability to the steering systems. Therefore, an EPS system needs to have an extra stability controller to eliminate the side effect of assist gain on system stability and attenuate the unpleasant vibration. In this paper, an accurate theoretical model is built and the method for evaluating system quality are suggested. The bench tests and vehicle experiments are carried out to verify the theoretical analysis.

Cabin heating and cooling loads of modern vehicles, notably electrically driven, represent a major portion of the overall vehicle energy consumption. Various concepts to reduce these loads have thus been proposed but quantitative experimental analysis or numerical predictions are scarcely available. Conventional 1D or zonal cabin models do not account adequately for strongly inhomogeneous cabin climate conditions. In this paper a new cabin model is presented, which delivers both temporally and spatially resolved data. The model uses a dynamic coupling algorithm including a CFD simulation of the cabin airflow, a model of the cabin structure and the detailed passenger Fiala Physiological Comfort (FPC) model.