Showing papers by "Saab Automobile AB published in 2003"

HCCI Combustion Phasing with Closed-Loop Combustion Control Using Variable Compression Ratio in a Multi Cylinder Engine

Abstract: This study applies Closed-Loop Combustion Control (CLCC) using Variable Compression Ratio (VCR) and cylinder balancing using variable lambda to solve the problem. Step changes of set points for combustion phasing, Compression Ratio (CR), and load together with ramps of engine speed and inlet air temperature are investigated. Performances of the controllers are investigated by running the engine at either a constant amount of injected fuel corresponding to an approximate load of 1.5 or 2.5 bar BMEP and/or constant speed of 2000 rpm. Commercial RON 92 gasoline is used in the test. The CLCC is found to be fast and effective and has a potential of handling step changes in a matter of cycles, while the speed and temperature ramps need some more optimization of the CLCC. The CR controller is very fast and has a time constant corresponding to three engine cycles at 2000 rpm.

Operating range in a Multi Cylinder HCCI engine using Variable Compression Ratio

Abstract: Homogenous Charge Compression Ignition (HCCI) is a promising part load combustion concept for future power train applications. Different approaches to achieve and control HCCI combustion are today investigated and compared, especially concerning operating range. The HCCI operating range for vehicle applications should at least cover contemporary emissions drive cycles. The operating range in terms of speed and load is investigated with a Naturally Aspirated (NA) four-stroke multi-cylinder engine with Port Fuel Injection (PFI). HCCI combustion control is achieved with Variable Compression Ratio (VCR) and inlet air preheating with exhaust heat. Both primary reference fuels and commercial gasoline are used in the tests. HCCI combustion with commercial gasoline is achieved over a load range from 0 to 3.6bar BMEP, and over a speed range from 1000 to 5000rpm. Maximum load is at 1000rpm and decreases with an approximately straight slope to zero at 5000rpm. NOx emissions are kept below 15ppm and the rate of pressure rise below 6bar/CAD throughout the operating range. Combustion efficiency is above 90% for all positive loads. High amounts of unburned HC as well as CO emissions decrease combustion efficiency to 70% at zero load. Brake efficiencies up to 33% are obtained.

Soft error rate increase for new generations of SRAMs

Abstract: We report on enhanced susceptibility for neutron-induced soft errors from accelerated testing of static random access memories (SRAMs), performed at Los Alamos National Laboratory. This enhancement is per bit of memory.

Particle filtering and Cramer-Rao lower bound for underwater navigation

Abstract: We have studied a sea navigation method relying on a digital underwater terrain map and sonar measurements. The method is applicable for both ships and underwater vessels. We have used experimental data to build an underwater map and to investigate the estimation performance. Since the problem is non-linear, due to the measurement relation, we apply a sequential Monte Carlo method, or particle filter, for the state estimation. The fundamental limitations in navigation uncertainty can be described in terms of the Cramer-Rao lower bound, which is interpreted in terms of the inertial navigation system (INS) error, the sensor accuracy and the terrain map excitation. Hence, the Cramer-Rao lower bound can be interpreted and used in the design for INS systems, sensor performance or, if these are given, how much terrain or depth excitation that is needed for use in positioning and navigation.

Level gauging system

Abstract: A radar level gauge for measuring the level of a surface of a product stored in a tank by use of a radar, where said radar transmits microwaves towards said surface and receives microwaves reflected by said surface and wherein said radar is adapted to transmit and receive said microwaves within two widely separated frequency bands. Widely separated frequency bands are chosen to utilize the differences in attenuation due to foam on the surface and the differences in beam-width or other disturbances. The ratio between the center frequencies of the two widely separated frequency bands can be quantified as at least greater than 1.5:1 or preferably greater than 2:1.

Power efficiency circuit

Abstract: A radar level gauge for measuring a level of a surface of a product in a tank having a two-wire process control loop, output circuitry coupled to the two-wire process control loop for setting in the loop a desired value of a loop current (I loop ) corresponding to the product level, a power supply circuitry coupled to the two-wire process control loop for receiving power from the loop and being a source of power for a microwave source, a microwave receiver, a measurement circuitry and the output circuitry and including a converter for transferring power from the loop to said power supply circuitry by means of feeding a first current (I DC/DC ) from the loop to the power supply circuitry, a current generator included in said output circuitry for generating in parallel to said first current a second current (I sh ) in the loop for maintaining said loop current at a value corresponding to said product level and a sensing circuit for determining the value of said second current and having an output indicative of the value of said second current.

Device and method in a level gauging system

Abstract: The invention relates to a pressure sealing device and a method for decreasing the cut-off frequency in such a pressure sealing device used in a radar level gauging system for gauging a filling level of a product kept in a container, the sealing device comprises a waveguide for feeding microwaves in at least one of the following mode types: transverse electric mode, transverse magnetic mode or hybrid mode. Said waveguide is sealed by a dielectric material. A center conductor is arranged at least partially within said dielectric material.

System and method in a radar level gauging system

Abstract: The present invention relates to the field of radar level gauging systems, in which a level of a surface of a product stored in a container is measured. The gauging system comprises: a radar level gauge arranged above the surface of the product which is arranged to transmit a microwave signal towards the product surface and receive a reflected microwave signal from the product surface; a calculation unit arranged to determine a measured value of the product level based upon the received signal; means for comparing the measured value of the product level with a predetermined value; and a second level gauge arranged closed to the bottom of the container and arranged to determine the product level when the measured value is below the predetermined value.

Radar level gauge with antenna arrangement for improved radar level gauging

Abstract: The present invention relates to a radar level gauge ( 1 ) comprising an antenna ( 2 ), a tank sealing ( 3 ), an electronics unit ( 4 ) and a waveguide feed ( 5 ) between the electronics unit ( 4 ) and the antenna ( 2 ). The waveguide ( 5 ) is essentially straight and has a 90°-symmetric cross section and is further arranged to accommodate two essentially orthogonal waveguide modes. The waveguide ( 5 ) further has a length (l) below two times the range resolution of said radar level gauge ( 1 ). The present invention further relates to a method for improved radar level gauging using a radar level gauge ( 1 ) as above.

A comparative study between two neutron facilities regarding SEU

Abstract: We report on a comparative study between two neutron facilities used for SEU studies, namely the Weapons Neutron Research facility at Los Alamos National Laboratory (a white neutron source), and the The Svedberg Laboratory in Sweden (a quasimono-energetic neutron source). The soft error rates generated from TSL are in excellent agreement with those from WNR. Moreover, an increase of the SER for small process technologies was observed.

System for level gauging and alarms

Abstract: Method and device for calculating the level of the surface (6) of a product (2) in a storage room (1) by means of a radar level gauging system, which includes a first gauging device (10) for calculating a first value of said level and functionally separated from said first gauging device a second gauging device (14) for calculating a second value of said level, wherein: a first signal (12) is produced being dependent of a preset first threshold value of said level in the first gauging device (10), a first current level value signal (19) is output from said first gauging device (10), a second signal (16) is produced in dependence of a preset second threshold value of said level in the second gauging device (14), a second current level value signal (20) is output from said second gauging device (14) and the value of the current level of said surface (6) is presented by means of an indicating unit (21) adapted to receive at least one of said first level value signal (19) and said second level value signal (20) for evaluation of the said current level value.

Circuit for multifrequency band radar level gauge

Abstract: A circuit for a radar level gauge for measuring the level of the surface of a product stored in a container, wherein the gauge includes a radar for transmitting microwave signals from a multiband antenna unit towards the surface for receiving microwave signals reflected by the surface and for determining the level based on an evaluation of the time lapsed between the received and the transmitted signals and said radar operating on at least two different frequency bands. The circuit includes: a first microwave provision means for providing a microwave signal of a first frequency band having a first center frequency, a second microwave provision means for providing a microwave signal of a second frequency band having a second center frequency. The ratio between the second and the first center frequency is quantified as at least greater than 1.5:1 and preferably greater than 2:1. Switches are operated by means of a control signal for switching the circuit to operate on said first frequency band or said second frequency band.

Controlled Tightening Over the Yield Point of a Screw: Based on Taylor’s Series Expansions

Abstract: The technique presented here focuses on the probabilistic nature of the different variables necessary for the calculation of screwed joints. The technique is based on Taylor's series expansions or Monte Carlo simulations of the utilization of a screw over its yield point. It is very useful for quality controllers and design engineers since it is able to predict, for instance, the minimum and maximum snug torques, permanent elongation, final torque and preload after tightening. Comparisons are made between the results found of Monte Carlo simulations, series expansions and the extreme-value method. It is suggested that the Monte Carlo method is the most appropriate.

Interactive system for providing information and optimizing the attendance in the areas of health and related ones

Abstract: An interactive system for providing information and optimizing the service in the health areas and those related thereto able to organize and provide, in an interactive way, information and instructional matters of interest to users (patients/clients) (5) on subjects concerning the health areas and those related thereto, said information being provided by an interactive software (3) (the registration application therefor having already been filed by the inventor of said system himself), showing narrated structured texts, explanatory videos and photographs related to several pathologies, its treatments, surgeries and the like, in a screen (2), as well as the introduction of the professional on duty (6) of the medical area or another area related thereto, his/her resume, a blank space for the most frequent doubts, as well as a space for advertising by advertisers (12) registered in the system, said software (3) being associated to an equipment (1) to be installed in any environment that is easily accessed by the users interested in the information therein, wherein, after said information is handled and attained, said user (5), now more informed, becomes more receptive, thus assisting the professional (5) in his/her consultation in a substantially interactive process, thus improving the rates of feedback acceptance and respect to the proposed treatments or surgeries, also providing spaces for disclosing products, services and researches that aim at generating a greater interest and benefits.

Head kinematics in mini-sled tests of foam padding: relevance of linear responses from free motion headform (FMH) testing to head angular responses.

Abstract: The revised Federal Motor Vehicle Safety Standard (FMVSS) No. 201 specifies that the safety performance of vehicle upper interiors is determined from the resultant linear acceleration response of a free motion headform (FMH) impacting the interior at 6.7 m/s. This study addresses whether linear output data from the FMH test can be used to select an upper interior padding that decreases the likelihood of rotationally induced brain injuries. Using an experimental setup consisting of a Hybrid III head-neck structure mounted on a mini-sled platform, sagittal plane linear and angular head accelerations were measured in frontal head impacts into foam samples of various stiffness and density with a constant thickness (51 mm) at low (approximately 5.0 m/s), intermediate (approximately 7.0 m/s), and high (approximately 9.6 m/s) impact speeds. Provided that the foam samples did not bottom out, recorded peak values of angular acceleration and change in angular velocity increased approximately linearly with increasing peak resultant linear acceleration and value of the Head Injury Criterion (HIC36). The results indicate that the padding that produces the lowest possible peak angular acceleration and peak change in angular velocity without causing high peak forces is the one that produces the lowest possible HIC36 without bottoming out in the FMH test.

In-band control mechanism for switching architecture

Abstract: Systems for in-band control that establish relationships between incoming data and one or more destinations to which the data is to be transmitted. In the in-band control embodiments described herein, a connection is established between two ends of a circuit by provisioning at one end of the circuit. A circuit connection table is kept at both ends of the circuit. This table contains the new and existing circuit connection information. A software process writes to the connection table at the local end of the circuit with the address information of the remote end of the circuit. The circuit connection information is to be periodically sent to the remote end to establish or tear down new connections.

Simulation of Human-Vehicle Interaction in Vehicle Design at Saab Automobile: Present and Future

Abstract: Developers, reviewers and users of human simulation tools claim that the use of these tools may reduce development time and development cost. However, before these benefits will be fully visible, there are some barriers to overcome. The aims of this case study are to identify which departments at Saab Automobile use some sort of human simulation tool today, and to identify the information flow and procedure when the tool is used. Four departments crash safety, packaging, production planning and vehicle ergonomics were identified as direct users of human simulation tools. The tools used were finite element with crash dummy representation, SAE human model, Safework and Ramsis. Communications between human simulation tool users are limited. Communications are done through the project management. The crash safety and packaging departments have formal descriptions of the human simulation process, whereas production planning and vehicle ergonomics have no formal process descriptions. To gain from the benefits of human simulation tools, Saab Automobile needs to adapt them to the organization and the organization to the tools. Integration of a working methodology is essential for effective and efficient use in the other human simulation departments where this is currently lacking. (Less)

Iterative solution of a hybrid method for Maxwell's equations in the frequency domain

Abstract: A hybrid method for solution of Maxwell's equations of electromagnetics in the frequency domain is developed as a combination between the method of moments and the approximation in physical optics. The equations are discretized by a Galerkin method and solved by an iterative block Gauss–Seidel method. The convergence of the iterations is studied theoretically and in numerical experiments. The accuracy of the hybrid method is compared to the method of moments for a cylinder with an incident field for different wavenumbers. Copyright © 2003 John Wiley & Sons, Ltd.

Separation frequency detection in a radar level gauge

Abstract: The present invention relates to a separation frequency detector circuit and a method for detection of a separation frequency in a radar level gauge. A first circuit element (1) is arranged to receive a first clock frequency, and a second clock frequency. An instantaneous value of said first clock frequency will be transferred to and held at an output Q of said first circuit element (1) once each period of said second clock frequency. A predetermined value will be transferred to and held at an output Q of a second circuit element (3) triggered by the output Q of said first circuit element (1) and said predetermined value will be cleared from said output Q of said second circuit element (3) a predetermined time period after being triggered. An output is obtainable as a short pulse with a leading edge which will be synchronized with the first change of the leading signal edge of said first circuit element (1).

Zündelektrodenanordnung an einem Verbrennungsmotor

Abstract: Zundelektrodenanordnung fur einen Zylinder in einem Verbrennungsmotor, beispielsweise einem Ottomotor, in dem ein Zylinderkopf (3) eine erste Elektrode (7) und eine zweite Elektrode (8) tragt, die miteinander zusammenwirken, wobei die erste Elektrode (7) an einer in dem Zylinderkopf (3) befestigten Zundeinrichtung (6) angeordnet ist, wobei sowohl die erste Elektrode (7) als auch die zweite Elektrode (8) relativ zu dem Zylinderkopf (3) bewegbar angeordnet sind, um eine variable Funkenstrecke und/oder eine variable Zundposition zu ermoglichen, und wobei die zweite Elektrode (8) in dem Zylinderkopf (3) getrennt von der Zundeinrichtung (6) angeordnet ist, dadurch gekennzeichnet, dass die erste Elektrode (7) sowohl in Langsrichtung des Zylinders als auch in einer Ebene im rechten Winkel zur Langsrichtung des Zylinders bewegbar ist.