Search Results

For the BMW V8 engine, a new LEV/EU3 emission concept has been developed by improvements to the previous engine management and secondary air supply and a complete new exhaust system. Beside the emission limits, also high engine output targets and high operating reliability were targeted. In addition the new exhaust system had to meet low cost targets. Based on these requirements an exhaust concept with separate pre catalyst and main catalyst was chosen. To reduce the heat mass and to optimize the pressure drop, 4.3mil/400cpsi thin wall ceramic substrates were used for the pre and main catalyst.

A new converter concept is introduced, which utilizes the additional space in the inlet cone of the converter. An optimized design is obtained by the application of computational fluid dynamics (CFD) and flow distribution measurements, resulting in up to 20% improved flow distribution through the substrate. In addition, the volume of the converter can be increased by approximately 15% using the same space envelope. Durability tests of the converter system have been performed using a thermal cycling test on an engine test bench for 135 hours. No deterioration of the substrate or mounting system occurred. The emissions performance was evaluated on a stationary dynamometer. The impact of the flow distribution on the temperature field and the conversion behavior during light-off and steady state operation were investigated. Under the current testing conditions, no differences in light-off behavior were determined, despite significant differences in the temperature field.

The automotive industry and emission system suppliers invest considerable efforts for the improvement of the conversion efficiency of a catalytic converter, in order to lower vehicle emission. One of the methods to improve the catalyst conversion efficiency is to use a higher cell density brick with a thinner wall to increase its geometric surface area. However, there is a significant drawback for the system - higher pressure loss along the brick. Moreover, the mechanical strength and thermal degradation of the brick become major concerns. In this paper, the concept of a brick with radially variable cell density is introduced to possibly resolve several issues. A CFD study was conducted to verify benefits in both flow efficiency and pressure loss along the brick with several different flow rates.

Ultrasonic, capacitive, and infrared (IR) occupant position sensors were tested to determine their compatibility with crash test dummies. In this phase of testing, the sensors' responses to a Hybrid III 50th percentile male crash test dummy were compared to those of a human male of similar size. After the data were compared, crash test dummy modifications were developed so that sensor responses to the dummies more closely resembled their responses to humans. Ultrasonic sensors detected little difference between the dummy and the human. However, testing of capacitive and infrared sensors revealed differences in their responses to a crash test dummy and a human subject.

Fleet tests conducted on electrical vehicles around the world have very clearly shown that battery-powered cars may be regarded as zero-emission vehicles with respect to their local environments only. Emission measurements on vehicles powered by internal-combustion engines equipped with optimized exhaust-post-treatment systems have indicated the prospects the latter offer for cleaning up the environment, i.e., for yielding negative emissions, when run at their normal operating temperatures. Replacing electric cars with SULEV's is thus a matter currently under discussion. This paper will cover the functions of the various individual components of such post-treatment systems, and will show that optimizing the interactions among those components will improve their catalytic efficiencies.

The air bag has proven effective in reducing fatalities in frontal crashes with estimated decreases ranging from 11% to 30% depending on the size of the vehicle [IIHS-1995, Kahane-1996]. At the same time, some air bag designs have caused fatalities when front-seat passengers have been in close proximity to the deploying air bag [Kleinberger-1997]. The objective of this study was to develop an accurate and repeatable out-of-position test fixture to study the deployment of air bags into out-of-position occupants. Tests were performed with a 5th percentile female Hybrid III dummy and studied air bag loading on the thorax using draft ISO-2 out-of-position (OOP) occupant positioning. Two different interpretations of the ISO-2 positioning were used in this study. The first, termed Nominal ISO-2, placed the chin on the steering wheel with the spine parallel to the steering wheel.

A new inflator specification, the “inflator thrust variable,” was developed to better explain measured mid-sized male, instrumented test dummy responses in the chest-on-module test condition. Specifically, controlled laboratory experiments were conducted with non-production, driver airbag modules with inflators of various outputs and gas constituents in an effort to assess their effects on a pertinent occupant response. Regression analyses showed that the inflator thrust variable is a better predictor of the observed variation in peak viscous criterion responses than either peak tank pressure or the related pressure rise rate when inflators of differing gas composition were compared.

TEMIC as an automotive electronics manufacturer has done research since several years to develop suitable sensors for occupant detection. The paper will present simulation results and technical solutions concerning this issue which is one of the key points in the future design of advanced airbags.

To introduce a new micro-safing sensor for automotive applications with excellent characteristics based on silicon micro-machining techniques to prevent malfunctions in air bag systems using an acceleration switch. This sensor is composed of an upper electrode, cantilever, and pedestal formed by silicon micro-machining. The upper electrode and cantilever contact mechanically when acceleration during collision is applied and the “ON” signal is output. To achieve a satisfactory result, we developed an optimal shape design using FEM simulation. Also, the frequency characteristic of 100Hz and threshold acceleration of 2-4 (G) are obtained by electrostatic force and chattering measure at the contact point. Other characteristics include high-speed response, compactness, and the fact it is inexpensive, making it highly suitable as a safing sensor for side air bag systems.

Steering control devices are used by people who have difficulty gripping the steering wheel. These devices have projections that may extend up to 14 cm toward the occupant. Testing indicated that contact with certain larger steering control devices with tall rigid projections could severely injure a driver in a frontal collision. In order to reduce this injury risk, an alternative, less injurious design was developed and tested. This design, which included replacing unyielding aluminum projections with compliant plastic ones, produced significantly lower peak contact pressure and less damage to the chest of a cadaver test subject, while maintaining the strength necessary to be useful.

In comparison to drivers exposed to steering-wheel airbag deployments in frontal crashes, there have been fewer front-seat passengers exposed to airbag deployments for 1) many of the cars in crashes did not have dual airbags and 2) the front passenger seat is less often occupied. Of the 826 airbag crashes detailed by UMTRI crash investigators at the time of this manuscript preparation, there were 145 front-seat passengers, exposed to instrument panel mounted airbags. Most of these front-seat passengers 124 were involved in the frontal crashes. There were 92 who were 16 years of age or older, 24 were under 12 years of age and 11 young teenagers, 13-15 years of age. Of those who were 16 years or older in frontal crashes 70% had an MAIS-1 injury. None of the MAIS-2 injuries were directly related to airbag deployments. Of the AIS-3+ level injuries, about two-thirds were not airbag related.

The primary function of the Occupant Classification System is to provide reliable passenger seat occupancy information to the automobile’s central processing unit to control airbag deployment. Our Occupant Classification (OC) sensor system is based on analysis of the seat occupancy pressure profile, which discerns human like from human unlike profiles. If the occupancy is identified as a person, an allocation into one of four morphologic ranges is made. Accordingly, children, light adults, heavy children, medium adults, heavy adults, etc. can be discerned (Figure 1).

The CVT offers high fuel economy, presumably because it ensures a low BSFC driving condition with its continuously variable ratio characteristics. Focusing solely on BSFC values, i.e., indices that represent the engine's thermal efficiency, is not enough, as substantial work loss occurs in the drivetrain, including the transmission and engine accessories, from the engine to wheels. Therefore, attention needs to be paid to the efficiency of the entire powerplant, including engine and transmission, rather than just focusing on engine thermal efficiency, as has been conventionally done. Engine and CVT controls should be integrated as in addition to the stoichiometric operation, an engine may be operated in modes of lean burn and exhaust-gas recirculation. This paper describes a newly developed algorithm for the calculation of the combinations between the engine torque and CVT ratio in order to achieve the highest overall efficiency for the engine and transmission system.

The 45RFE is a new generation electronically controlled rear wheel drive transmission. It employs real-time feedback, closed-loop modulation of shift functions to achieve excellence in shift quality and to meet severe durability goals. The 45RFE uses no shift valves; all friction element applications are effected with high-flow electro-hydraulic solenoid valves. A unique gear train arrangement of three planetary carriers allows all sun and annulus gears to have identical numbers of teeth and to use common pinion gears in all carriers. This results in substantial manufacturing simplification. The three-planetary system is designed for four forward ratios of 3.00, 1.67, 1.00 and 0.75 and one reverse gear ratio equal to the low gear ratio. A fifth ratio of 1.50 is used mainly in certain kick-down shift sequences for highway passing. A sixth forward ratio, an additional overdrive ratio of 0.67, is available in the hardware.

For side airbag systems it is necessary to measure the acceleration within a time of less than 3 ms in order to inflate the side airbag in time. A new generation of side airbag sensors that uses a linear accelerometer is presented. The evaluation circuit includes amplification, temperature coefficient compensation, two wire unidirectional current interface, and a zero-offset compensation. The sensing element for the measurement of acceleration is a surface micromachined accelerometer. In order to minimise the production costs the surface micromachined sensor element and the corresponding evaluation ASIC are packaged into a standard PLCC28 housing. For the entire function only few external components are necessary. During the power-on cycle an internal selftest is carried out and the result is transmitted to the airbag control unit. Most important results of the characterisation are presented.

MANN+HUMMEL has developed a centrifugal oil cleaner focused on the separation of soot from oil. The basic setup and operation principle of a free jet driven centrifugal oil cleaner and its integration into an engine oil system will be explained. The development was supported by a new simulation tool, which predicts the centrifugal cleaner performance using computer analysis. This includes both the prediction of rotor speed and particle separation. Additionally, MANN+HUMMEL performed a detailed rotor design analysis in order to reduce torque resistance, to improve environmental protection and reduce cost.

The correct timing of the diesel injection pump on engine is of major importance for all functions of the engine and for its exhaust emissions, during production pass off as well as in the field. Within the diesel service workshops a variety of devices exist to test the timing of the injection pump on engine. Most of them operate by clamp-on transducer being fitted to the injection pipe. A large uncertainty exists concerning the accuracy of such timing systems. Most diesel engine manufacturers do not have confidence in the timing devices capability and, therefore, do not recommend their usage. A working group within the International Organization for Standardization (ISO) adopted a method for the validation of these measurement systems, which usually is used to judge the capability of measurement gauges for industrial production processes.

Current crash avoidance systems combine vehicle speed with knowledge of position (and change in position) of potential obstacles in front of the vehicle to trigger alarms warning of impending collisions. The various alarm levels are triggered using a simple set of minimum time delays. Although knowledge of on-board vehicle braking capability is not currently incorporated into these systems, such knowledge can improve the effectiveness of crash avoidance systems. A round robin test series of performance based brake testers (PBBTs) was conducted in which the brake forces on several configurations of control vehicles were measured. Using the PBBT-reported brake forces and vehicle weights, combined with knowledge of limiting tire/road coefficient of friction, the maximum deceleration potential can be determined and incorporated into on-board crash avoidance systems.

Extensive modeling and simulation studies have been carried out to evaluate the performance of systems for avoiding run-off-road crashes. Results show that the effectiveness of in-vehicle crash avoidance systems depends on how well they can be tailored to specific vehicle, driver, and roadway characteristics. To this end, a major focus of these studies is the development of improved driver lane-keeping models based on statistical analyses of data collected in driving experiments conducted on highways, rural roads, and test tracks. In recent simulation studies using improved driver models, the performance of crash avoidance systems in tractor-trailers and passenger cars has been compared over a wide range of incipient run-off-road crash conditions. Heavy trucks present a greater challenge for run-off-road crash avoidance systems, because they slightly but frequently leave the lane even under controlled driving, and because they are less stable during recovery maneuvers.