Saab Automobile AB

About: Saab Automobile AB is a based out in . It is known for research contribution in the topics: Radar & Signal. The organization has 760 authors who have published 890 publications receiving 11811 citations.

A Single Polarized Triangular Grid Tapered-Slot Array Antenna

Abstract: A triangular grid single polarized tapered-slot array antenna for radar applications is studied. Compared with a rectangular grid an equilateral triangular grid allows a larger unit cell without any onset of grating lobes. Since single polarized tapered-slots in triangular grids support guided modes, which cause scan blindness, the increase in unit cell size is smaller than the optimal 15%. The design presented in the paper is capable of scan angles out to 60° from broadside in the E and H planes. To improve the match over the radar band a local minimum in the active reflection coefficient is positioned at the most critical scan direction, resulting in a reflection coefficient that is less than -12 dB in the X-band. To reduce the radar cross section for the cross-polarization an absorbing layer is positioned above the ground plane, which affects some of the guided modes that lead to scan blindnesses. An experimental antenna with 16 × 16 elements was built, and it was found that the H-plane performance for large scan angles for the finite antenna deviates more than expected from the infinite array approximation. Otherwise both mutual coupling measurements and embedded element patterns agrees well with the numerical results.

Producing signals denoting location of edges of a finished surface on a partly finished workpiece

Abstract: An elongated workpiece having unfinished side surfaces inclined laterally downwardly and outwardly from a finished top surface is scanned to produce signals denoting location of the longitudinal edges of the top surface at numerous points along them. An elongated scanning zone, extending across the workpiece, is translated all along the workpiece. In synchronism with scanning zone translation the workpiece is alternately illuminated from opposite sides at a low angle of incidence to the top surface to shadow first one side surface, than the other. Scanning lengthwise along the scanning zone is synchronized with translation of that zone and lighting alternation.

Combustion engine with variable compression ratio

Abstract: An internal combustion engine (10) is designed with a cylinder section (11) which is pivoted on a crankcase section (13) to provide different compression ratios. The crankcase section (13) is provided with raised lateral walls (21, 22, 24, 25) with upper surfaces (82-85), which lie in the same plane and thereby allow simple assembly of a seal (34) between the cylinder section (11) and crankcase section (13). The lateral walls (21, 22, 24, 25) also enable auxiliary devices for the engine to be easily secured without having to allow for the mobility of the cylinder section (11) relative to the crankcase section (13).

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.

HCCI Heat Release Data for Combustion Simulation, based on Results from a Turbocharged Multi Cylinder Engine

Abstract: When simulating homogenous charge compression ignition or HCCI using one-dimensional models it is important to have the right combustion parameters. When operating in HCCI the heat release parameters will have a high influence on the simulation result due to the rapid combustion rate, especially if the engine is turbocharged. In this paper an extensive testing data base is used for showing the combustion data from a turbocharged engine operating in HCCI mode. The experimental data cover a wide range, which span from 1000 rpm to 3000 rpm and engine loads between 100 kPa up to over 600 kPa indicated mean effective pressure in this engine speed range. The combustion data presented are: used combustion timing, combustion duration and heat release rate. The combustion timing follows the load and a trend line is presented that is used for engine simulation. The combustion duration in time is fairly constant at different load and engine speeds for the chosen combustion timings here. The heat release rate is fitted to a Wiebe function where the heat release parameter m is found. It is shown that this parameter m scale to the load and the presented trend line is used for simulating the heat release. When the engine is operated with negative valve overlap the mass flow is reduced through the engine. In an engine simulation the valve timings has to be estimated for different intake temperatures and boost pressure levels. By using the intake temperature at intake valve closing as a prediction tool for the temperature at top dead center, the exhaust valve closing timing can be estimated and will then follow the real test results closely as shown in a GT-Power simulation. The turbocharged test engine is an in-line four cylinder gasoline engine with a total displacement of 2.2 l. The engine is direct injected of spray-guided type. To achieve HCCI combustion the engine is operated with low lift and short duration valve timings where the variable negative valve overlap is used for combustion control. (Less)