1. A method of operating a vehicle propulsion system including an engine having an intake manifold communicating with two compressors arranged in separate intake passages, the method comprising:
adjusting a boost pressure provided to the engine by the first and the second compressors in response to a total flow of air consumed by the engine, said first and second compressors cooperating to provide the total flow; and
during an imbalanced flow condition between the first and the second compressors, choking flow through the first compressor before the second compressor experiences surge.
2. The method of claim 1, where adjusting the boost pressure includes limiting the boost pressure in response to the total flow of air, and where during the imbalanced flow condition, the flow through the first compressor is greater than flow through the second compressor, and where said choking limits a further reduction of flow through the second compressor, and where an output shaft of the engine system is coupled to a vehicle drive wheel via a transmission, the method further comprising: adjusting the total flow by adjusting a gear ratio of the transmission; and adjusting the boost pressure limit in response to said adjustment of the transmission gear ratio.
3. The method of claim 2, wherein said adjusting the total flow includes increasing the flow rate by increasing the gear ratio; and increasing the boost pressure limit in response to the increased gear ratio.
4. The method of claim 1, wherein the total flow of air includes a total volumetric flow rate of intake air.
5. The method of claim 1, wherein the first compressor is fixedly coupled to a first turbine arranged in a first exhaust stream of the engine and the second compressor is fixedly coupled to a second turbine arranged in a second separate exhaust stream of the engine; the method further comprising limiting the boost pressure provided to the engine by adjusting a flow rate of the first exhaust stream provided to the first turbine and adjusting a flow rate of the second exhaust stream provided to the second turbine.
6. The method of claim 5, wherein the flow rate of the first exhaust stream provided to the first turbine is adjusted by adjusting an opening a first wastegate arranged in a first bypass passage of the first turbine; and wherein the flow rate of the second exhaust stream provided to the second turbine is adjusted by adjusting an opening of the second wastegate arranged in a second bypass passage of the second turbine.
7. The method of claim 1, further comprising adjusting the total flow by adjusting an opening of a throttle arranged along an intake passage of the engine common to the first and second compressors; and increasing the boost pressure limit in response to the opening of the throttle.
8. The method of claim 7, wherein the boost pressure limit is increased by adjusting a first vacuum pressure provided to a first wastegate actuator arranged along a first turbine bypass passage of the engine and by adjusting a second vacuum pressure provided to a second wastegate actuator arranged along a second turbine bypass passage of the engine.
9. A vehicle propulsion system, comprising:
an internal combustion engine having a plurality of cylinders;
a common air intake manifold communicating with the plurality of cylinders;
a first air intake passage having a first end communicating with the air intake manifold;
a first compression device arranged along the first air intake passage;
a second air intake passage having a first end communicating with the air intake manifold;
a second compression device arranged along the second air intake passage, said first and second compression devices receiving intake air from a common air supply; and
a control system including memory containing instruction executable to:
control the first and second compression devices to limit a level of boost pressure provided to the intake manifold of the engine based on the volumetric flow rate of air consumed by the engine.
10. The system of claim 9, wherein a second end of the first intake passage and a second end of the second intake passage are joined at a first end of a common intake passage, said common intake passage having a second end communicating with an ambient air supply.
11. The system of claim 9, further comprising a throttle arranged along a common intake passage coupling the first end of the first air intake passage and the first end of the second air intake passage to the air intake manifold; and wherein the control system is further configured to adjust an opening of the throttle to adjust the volumetric flow rate of air consumed by the engine.
12. The system of claim 9, further comprising a vehicle drive wheel and a transmission, wherein an output shaft of the engine is coupled to the vehicle drive wheel via the transmission, and wherein the control system is further configured to increase the total volumetric flow rate of air consumed by the engine by increasing a gear ratio of the transmission in response to an indication of compressor surge; and wherein the control system is further configured to increase the level of boost pressure in response to said increase of the transmission gear ratio.
13. The system of claim 9, further comprising an anti-surge valve configured to open to communicatively couple the first air intake passage downstream of the first turbine to a second end of the first intake air passage and to communicatively couple the second air intake passage downstream of the second turbine to a second end of the second intake air passage; and wherein the control system is further configured to increase a volumetric flow rate of air flowing through the first and second compressors without substantially increasing the total volumetric flow rate of air consumed by the engine by selectively opening the anti-surge valve.
14. The system of claim 9, further comprising a first exhaust passage coupled to a first portion of the plurality of engine cylinders; a second exhaust passage coupled to a second portion of the plurality of engine cylinders; a first exhaust turbine arranged along the first exhaust passage and rotationally coupled with the first compression device; a second exhaust turbine arranged along the second exhaust passage and rotationally coupled with the second compressor; and wherein the control system is further configured to limit a first flow rate of exhaust gases provided to the first turbine and a second flow rate of exhaust gases provided to the second turbine to limit the level of boost pressure provided to the intake manifold of the engine.
15. The system of claim 14, further comprising a first bypass passage bypassing the first turbine; a first wastegate arranged along the first bypass passage; a second bypass passage bypassing the second turbine; a second wastegate arranged along the second bypass passage; and wherein the control system is configured to limit the first flow rate by increasing an opening of the first wastegate and is configured to limit the second flow rate by increasing an opening of the second wastegate.
16. The system of claim 9, further comprising a differential pressure sensor configured to provide an indication of pressure difference between the first exhaust passage upstream of the first turbine and the second exhaust passage upstream of the second turbine; and wherein the control system is further configured to reduce a pressure difference indicated by the differential pressure sensor by adjusting a first vacuum pressure provided to an actuator of the first wastegate relative to a second vacuum pressure provided to an actuator of the second wastegate.
17. A method of operating a twin turbocharged engine system including an internal combustion engine receiving intake air from a common ambient air supply via a first compressor of a first turbocharger and a second compressor of a second turbocharger, said first compressor rotationally coupled with a first exhaust turbine arranged in a first branch of the exhaust system and said second compressor rotationally coupled with a second exhaust turbine arranged in a separate second branch of the exhaust system, the method comprising:
during a first imbalanced flow condition between the first and second compressors while operating the engine at a higher volumetric flow rate of intake air, choking the first compressor before the second compressor experiences surge by selectively opening bypass wastegates of the first and the second turbines to limit a boost pressure provided to the engine by the first and second compressors to a higher level; and
during a second imbalanced flow condition between the first and second compressors while operating the engine at a lower volumetric flow rate of intake air, choking the first compressor before the second compressor experiences surge by selectively opening the bypass wastegates of the first and the second turbines to limit the boost pressure provided to the engine by the first and second compressors to a lower level.
18. The method of claim 17, further comprising, adjusting a throttle arranged along an intake passage of the engine common to both the first and second compressors to adjust the volumetric flow rate of intake air between the higher and the lower values.
19. The method of claim 17, further comprising, adjusting a gear ratio of the transmission to adjust the volumetric flow rate of intake air between the higher and the lower values.
20. The method of claim 17, wherein limiting the boost pressure to the lower level includes providing a first vacuum pressure to a flexible diaphragm of each actuator of the turbine bypass wastegates; and wherein limiting the boost pressure to the higher level includes providing a second vacuum pressure to the flexible diaphragm of each actuator of the turbine bypass wastegates, said first vacuum pressure different than said second vacuum pressure.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A semiconductor device comprising:
a semiconductor substrate;
a first isolation oxide film provided in a main surface of said semiconductor substrate; and
an inductance element provided on a region in which said first isolation oxide film is formed with an interlayer insulation film therebetween,
wherein said first isolation oxide film is provided so that a horizontal distance between an end surface of said first isolation oxide film and a nearest one of end surfaces of said inductance element is not less than a vertical distance between a lower surface of said inductance element, which is opposed to said first isolation oxide film, and a surface of said semiconductor substrate.
2. The semiconductor device according to claim 1, wherein:
said semiconductor substrate is an SOI substrate comprising a substrate portion to be a foundation, a buried oxide film provided on said substrate portion, and an SOI layer provided on said buried oxide film; and
said vertical distance is a vertical distance between the lower surface of said inductance element and a surface of said substrate portion.
3. The semiconductor device according to claim 2, wherein:
said first isolation oxide film includes a first portion having a first width and extending in a depth direction with respect to a surface of said buried oxide film, and a second portion having a second width smaller than said first width and being continuously formed under said first portion, extending in a depth direction with respect to said surface of said buried oxide film to reach said buried oxide film; and
said end surface of said first isolation oxide film is an end surface of said second portion.
4. The semiconductor device according to claim 2, wherein
said first isolation oxide film has a predetermined width and extends in a depth direction with respect to a surface of said buried oxide film.
5. A semiconductor device comprising:
a semiconductor substrate;
a first isolation oxide film provided in a main surface of said semiconductor substrate;
an inductance element provided on a region in which said first isolation oxide film is formed with an interlayer insulation film therebetween; and
a conductor layer provided at a height between said first isolation oxide film and said inductance element;
wherein said conductor layer is provided so that a horizontal distance between an end surface of said conductor layer and a nearest one of end surfaces of said inductance element is not less than a vertical distance between a lower surface of said inductance element and a surface of said semiconductor substrate.
6. The semiconductor device according to claim 5, wherein
said first isolation oxide film is provided so that a horizontal distance between an end surface of said first isolation oxide film and a nearest one of end surfaces of said inductance element is not less than a vertical distance between the lower surface of said inductance element and the surface of said semiconductor substrate.
7. The semiconductor device according to claim 5, wherein
said semiconductor substrate is an SOI substrate comprising a substrate portion to be a foundation, a buried oxide film provided on said substrate portion, and an SOI layer provided on said buried oxide film; and
said vertical distance is a vertical distance between the lower surface of said inductance element and a surface of said substrate portion.
8. The semiconductor device according to claim 7, wherein
said first isolation oxide film includes a first portion having a first width and extending in a depth direction with respect to a surface of said buried oxide film, and a second portion having a second width smaller than said first width and being formed under said first portion, extending in a depth direction with respect to said surface of said buried oxide film to reach said buried oxide film; and
said end surface of said first isolation oxide film is an end surface of said second portion.
9. The semiconductor device according to claim 7, wherein
said first isolation oxide film has a predetermined width and extends in a depth direction with respect to a surface of said buried oxide film.
10. A semiconductor device comprising:
a semiconductor substrate;
a first isolation oxide film provided in a main surface of said semiconductor substrate;
an inductance element provided on a region in which said first isolation oxide film is formed with an interlayer insulation film therebetween; and
a dummy pattern region provided around said first isolation oxide film and divided by a second isolation oxide film having a smaller width than said first isolation oxide film in a plan view.
11. The semiconductor device according to claim 10, wherein
said first isolation oxide film is provided so that a horizontal distance between each end surface of said first isolation oxide film and a nearest one of end surfaces of said inductance element is not less than a vertical distance between a lower surface of said inductance element which is opposed to said first isolation oxide film, and a surface of said semiconductor substrate.
12. The semiconductor device according to claim 10, wherein:
said semiconductor substrate is an SOI substrate comprising a substrate portion to be a foundation, a buried oxide film provided on said substrate portion, and an SOI layer provided on said buried oxide film; and
said vertical distance is a vertical distance between the lower surface of said inductance element and a surface of said substrate portion.
13. The semiconductor device according to claim 12, wherein
said first isolation oxide film includes a first portion having a first width and extending in a depth direction with respect to a surface of said buried oxide film, and a second portion having a second width smaller than said first width and being continuously formed under said first portion, extending in a depth direction with respect to said surface of said buried oxide film to reach said buried oxide film; and
said end surface of said first isolation oxide film is an end surface of said second portion.
14. The semiconductor device according to claim 12, wherein
said first isolation oxide film has a predetermined width and extends in a depth direction with respect to a surface of said buried oxide film.
15. The semiconductor device according to claim 10, wherein
said first isolation oxide film is rectangular in shape in a plane view; and
said dummy pattern region has a width 5% or more of a length of a short side of said first isolation oxide film.
16. The semiconductor device according to claim 15, wherein:
said dummy pattern region includes a field portion defined by said second isolation oxide film; and
an area ratio of said second isolation oxide film in said dummy pattern region to said field portion is set to be approximately 1:1.