In the present paper we will outline the principles, designs, problems and benefits of electrochromic coatings and present our own laboratory results. The effect of electrochromic coatings on the thermal comfort of a parked vehicle is theoretically calculated and the results confronted with the performances of selective coatings.
The windows of a vehicle have to satisfy the following driver and passenger needs concerning visibility and climate perception both related to active safety: transparency, reluctance, dazzling, glare and diffused light (scattering). All functions are related to visibility and so to the optics of glazing, solar control, deicing, defogging, demisting. The task of material science is to find the multifunctional glasses solving simultaneously problems of visibility, safety and comfort. Particular kind of glasses, colored, wired, coated, electrochromic, liquid crystal, photochromic can be already considered solutions which can operate passively or actively. The example of passive solar control and active heatable coated glasses is shown as a possible practical multifunctional glass very soon.
Predictable and unpredictable forces will change the direction of the charge-air systems industry. The driver of diesel engine development will be the stringent emissions regulations of the 1990s. The drivers in the gasoline engine market will be improved fuel economy, performance, durability and emissions. Forces will also influence the charge-air marketplace, including changes in emission standards, national fiscal policies, political issues, fuel prices, alternate fuels and consumer tastes. The world community mandate for engines that are clean, quiet, durable and fuel efficient will be satisfied, increasingly, by first-tier component suppliers developing integrated systems solutions.
Transfer Path Analysis (TPA) is a widely used methodology in Noise, Vibration and Harshness (NVH) analysis of motor vehicles. Either it is used to design a vehicle from scratch or it is applied to root cause an existing NVH problem, TPA can be a useful tool. TPA analysis is closely related to the concept of partial contribution. The very basic assumption in TPA is that the summation of all partial contributions from different paths constitutes the total response (which could be either tactile or acoustic). Another popular concept in NVH analysis of vehicles is the component sensitivity. Component sensitivity is a measure of how much the response changes due to a change in one of the components of the system, i.e., the thickness of a panel or elastic rate of an engine mount. Sensitivity rates are more popular among CAE/Simulation community, simply because they are reasonably easy to calculate using mathematical models.
An overview of model development for seated occupants is presented. Two approaches have been investigated for modeling the vertical response of a seated dummy: finite element and simplified mass-spring-damper methods. The construction and implementation of these models are described, and the various successes and drawbacks of each modeling approach are discussed. To evaluate the performance of the models, emphasis was also placed on producing accurate, repeatable measurements of the static and dynamic characteristics of a seated dummy.
Modern trends in noise control engineering have subjected the automobile to the “drained swamp” syndrome. Squeaks and rattles (S&R) have surfaced as major concerns. Customers increasingly perceive S&R as direct indicators of vehicle build quality and durability. The high profile nature of S&R has led manufacturers to formulate numerous specifications for assemblies and components. Even so, a large majority of buzz, squeak and rattle (BSR) issues are identified very late in the production cycle, some often after the vehicle is launched. Traditionally, the “find-and-fix” approach is widely adopted, leading to extensive BSR warranty bills. The “design-right-the-first-time” approach must replace the “find-and-fix” approach. Due to the vast breadth and depth of S&R issues, a comprehensive summary of the present state of the art is essential. This paper includes a literature survey of the current state of the art of S&R, and discusses the methods available to further advance it.
This paper provides twelve rules to help reduce four key ergonomic risk factors (force, frequency, posture and mechanical stress). These rules were developed to assist individuals who may not have received extensive ergonomic training but who are involved in implementing any changes (major or minor) to manufacturing work stations. This includes changes in task and/or changes in equipment. A complete ergonomic analysis of a work situation is a good idea in most cases, but these rules will avoid many of the commonly occurring problems if applied early in the design or modification of a workplace.
The oxidation of surrogate diesel fuels composed of mixtures of three pure hydrocarbons with and without their cetane numbers chemically enhanced using 2-ethylhexyl nitrate (2-EHN) is studied in a variable pressure flow reactor over a temperature range 500 - 900 K, at 12.5 atmospheres and a fixed reaction time of 1.8 sec. Changes in both low temperature, intermediate temperature, and hot ignition chemical kinetic behavior are noted with changes in the fuel cetane number. Differences appear in the product distribution and in heat release generated in the low and intermediate temperature regimes as cetane number is increased. A chemically enhanced cetane fuel shows nearly identical oxidation characteristics to those obtained using pure fuel blends to produce the enhanced cetane value. The decomposition chemistry of 2-EHN was also studied. Pyrolysis data of 10% 2-EHN in n-heptane and toluene are reported.
Although the total number of car occupants involved in accidents in Germany has not significantly reduced during the past 10 years, the number of fatalities has steadily decreased. Most of the severe accidents result from a loss of control of the car. The problem of the driver losing control of his car will be explained. This problem is then used to formulate the goal for the vehicle dynamics control system ESP (Electronic Stability Program, also known as VDC). The approach chosen to reach this goal will then be shown. It will be shown that the vehicle slip angle is a crucial indicator for the maneuverability of the automobile. Since the complete vehicle state is not readily available, estimation algorithms are used to supply the control algorithms with sufficient information. With the automatic control of the slip angle the required yaw moment can be generated by individual wheel slip control.
Vehicle stability augmentation has been refined over many years, and currently there are commercial systems that control right/left braking and throttle to create vehicles that remain controlled when road conditions are very poor. These systems typically use yaw rate and lateral acceleration in their control philosophy. The tire/road friction coefficient, μ, has a significant role in vehicle longitudinal and lateral control, and there has been associated efforts to measure or estimate the road surface condition to provide additional information for the stability augmentation system. In this paper, a differential braking control strategy using yaw rate feedback, coupled with μ feedforward is introduced for a vehicle cornering on different μ roads. A nonlinear 4-wheel car model is developed. A desired yaw rate is calculated from the reference model based on the driver steering input.
Stochastic simulation is used to account for the uncertainties inherent to the system and enables the study of crash phenomenon. For analytical purposes, random variables such as material crash properties, angle of impact, human response and the like can be characterized using statistical models. The methodology outlined in this approach is based on using the information about the probability of random variables along with structural behavior in order to quantify the scatter in the structural response. Thus the analysis gives a more complete picture of the actual simulation. Practical examples for the use of this technique are demonstrated and an overview of this approach is presented.
This paper will discuss the various tools used to measure the steering and suspension properties of a vehicle. Measuring the kinematic and compliance properties of the steering and suspension systems is an important part of the vehicle development process. Some of the ways these measurements are used include confirmation of vehicle design and build, to create and correlate CAE models, and for diagnosis of steering and handling concerns. Understanding exactly how the steering and suspension systems are performing is an important step in the development process. We have found that by employing the proper tools and methods, plus having a defined vehicle dynamics fingerprint process, that most issues and concerns can be successfully resolved.
This paper presents the results of a recent project of IKCo’s research center to modify the Paykan 1600’s rear suspension mechanism with the purpose of improving the car’s comfort, stability and handling qualities. The car was originally equipped with a solid rear axle with leaf springs. By replacing the original mechanism with a three-link mechanism with panhard bar and coil springs, the ride comfort and handling characteristics of the car were noticeably improved.3-D, nonlinear ride and handling models were developed and analyzed to determine the important kinematics and dynamic effects of the new mechanism on vehicle responses. To verify the analytical results, subjective tests were carried out on the vehicle. The results of these tests demonstrated remarkable improvement of the dynamics behavior of the car.
Ideally, ride comfort evaluation, or any field evaluating human perception of motion, would be greatly simplified if such evaluation could be made based upon a single number or a simple curve that correlates with the perception of motion. The paper describes a ride comfort descriptor of pitch movements that is simple to use in virtual prototyping and ride comfort evaluations. This descriptor, i.e. Pitch Indicator, is validated in a calculation model, ride comfort measurements and subjective evaluations.
A method was developed for determining the unknown initial velocity of vehicles in yaw based upon evidence of the vehicle’s trajectory. The problem is formulated as an optimization problem by minimizing the error between a simulation trajectory and the known vehicle trajectory as per tire marks. A search simulation is coded in Matlab. An objective function is formulated based upon the error between the search simulation’ trajectories and the trajectory prescribed by the tire mark evidence. Initial conditions and step driver inputs are the design variables. A genetic algorithm routine coded in Matlab, GAOT (Genetic Algorithm Optimization Toolbox), is implemented to determine the solution vector that results in a simulation trajectory that minimizes the objective function. Target simulations are created using EDVSM (Engineering Dynamics Vehicle Simulation Model). The optimization algorithm is implemented and errors in the resultant velocities are reported.
Milliken Research Associates has developed a new simulation tool, named Vehicle Dynamics Simulation-Matlab/Simulink (VD-M/S). Produced for the government's Variable Dynamic Testbed Vehicle (VDTV), VD-M/S is an 18 degree-of-freedom simulation programmed in the Matlab/Simulink environment. It contains a detailed non-linear tire model, kinematic and compliance effects, aerodynamic loadings, etc. as do MRA's other simulation programs. Unique to VD-M/S is its development from Day One as a simulation catered to the inclusion and exploration of active systems within the vehicle.
Used Diesel oil viscosity is commonly measured by the kinematic method as outlined in the Mack T-8 used diesel soot procedure (ASTM D 5967 for used oil from Mack T-8 engine test, and CEC L-83-A-97 for used oil from PSA XUD11 ATE engine test). The limitations of the kinematic viscosity measurement for used oils heavily loaded with carbonaceous matters, have led to a new proposed method which may be better suited for these oils. This paper describes an investigation about the rheology of Diesel oils heavily loaded with carbonaceous matters. The kinematic viscosity result (measured with only the first sphere) was presented as a function of shear rate (imposed by differents kinematic viscometers) and demonstrated that the behaviour of these oils is not newtonian for low shear rates.
An analytical approach to developing motorcycle suspensions is presented. Typical uncontrolled and subjective evaluations that place limits on suspension development are curtailed through the use of a laboratory-based road simulation technique, which evaluates vehicle ride quality. Ride comfort is calculated using a specifically tailored NASA model after primary and secondary frequency regimes have been established for this type of motorcycle. Correlation between road and laboratory simulation is measured and compared to the road data variance. A designed experiment evaluates changes in ride quality as a function of suspension and tire pressure adjustments. Various suspension settings are repeated on the simulator and corresponding ride numbers are calculated for both environments. An analysis is performed to correlate ride quality improvements on the simulator with ride quality improvements in the field.
When a motorcycle runs with hands free riding, the change of the handle deflection angle is interlocked with the vehicle body (frame) bank angle, which is operated by the rider lean angle and caused by the disturbance of road surface. In this report, the motion of the rider who maintains the upright stability of a motorcycle in hands free and hold grips running at low speeds was studied from the experiment with measuring the vehicle frame bank angle, the rider's lean angle and the handle deflection angle, and the rider's feeling evaluation concerning the stability.