1. A method of operating a four-stroke gasoline direct-injection controlled auto-ignition combustion engine having at least one cylinder with direct fuel injection and containing a piston reciprocably connected with a crank and defining a variable volume combustion chamber including an intake valve controlling communication with an air intake and an exhaust valve controlling communication with an exhaust outlet, the method comprising:
operating the engine with two sequential pairs of expansion and contraction strokes during two revolutions of the crank;
opening both the intake and exhaust valves during terminal portions of the expansion strokes and initial portions of the contraction strokes; and
injecting fuel directly into the combustion chamber for mixing with retained gases and igniting the fuel near the ends of the contraction strokes;
whereby combustion gases are expanded to produce power during major portions of the expansion strokes when the valves are closed, combusted gases are blown down into the exhaust outlet and the air inlet as the valves are opened and the combusted gases are partially redrawn into the cylinder with fresh air during the terminal portions of the expansion strokes, such that the air and exhaust gas charges are heated by the hot exhaust gases; and
portions of the charges are expelled into the exhaust outlet and the air intake during the initial portions of the contraction strokes and the remaining portions of the charges and injected fuel are compressed during major portions of the contraction strokes after closing of the valves for ignition of the resulting compressed charges of the dilute fuelair and exhaust gas mixture.
2. A method as in claim 1 including injecting equal fuel charges during consecutive pairs of expansion and contraction strokes to provide equivalent power output for consecutive crank revolutions.
3. A method as in claim 1 wherein lift curves of the intake and exhaust valves are identical in timing and profile.
4. A method as in claim 1 including delivering specified amounts of fresh combustion air to the combustion chamber during each crank revolution.
5. A method as in claim 1 including varying the timing of the intake and exhaust valve openings to provide fresh combustion air flow due to piston motion.
6. A method as in claim 1 including providing an auxiliary charging device to provide fresh combustion air flow.
7. A method as in claim 1 including providing a flow control valve to promote fresh combustion air flow to the combustion chamber.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A calibration device, capable of calibrating a gain of a radiometer, comprising:
an actuator, receiving a calibration signal outputted from a control unit; and
a micro-electromechanical-system (MEMS) unit, coupled to the actuator,
wherein the actuator enables the MEMS unit to shield an antenna of the radiometer according to the calibration signal, such that the radiometer generates an environmental signal according to an equivalent radiant temperature received from the MEMS unit, and the control unit calibrates the gain of the radiometer according to the environmental signal.
2. The calibration device as claimed in claim 1, further comprising:
an insulation unit, having a groove in which the antenna is disposed.
3. The calibration device as claimed in claim 1, wherein the radiometer comprises a low noise amplifier, a power detector and a variable gain amplifier.
4. The calibration device as claimed in claim 1, wherein the radiometer is a microwave radiometer.
5. The calibration device as claimed in claim 1, wherein the MEMS unit comprises:
a metal plate, configured to shield the antenna; and
a pushpull bar, having a first terminal and a second terminal respectively coupled to the metal plate and the actuator, such that the metal plate shields the antenna when the actuator pushes or pulls the pushpull bar according to the calibration signal.
6. The calibration device as claimed in claim 1, wherein the MEMS unit comprises:
a gate, having a metal plate, wherein the metal plate shields the antenna when the gate operates in a closed state; and
a torsion beam, coupled between the gate and the actuator to separate the gate and the actuator, such that the gate respectively operates in the closed state and an open state when the actuator respectively operates at a first voltage level and a second voltage level according to the calibration signal.
7. The calibration device as claimed in claim 1, wherein the MEMS unit comprises:
a metal plate, configured to shield the antenna; and
a flexible rod, having a first terminal and a second terminal respectively coupled to the metal plate and the actuator, such that the metal plate shields the antenna when the actuator flexes the flexible rod according to the calibration signal.
8. A calibration system, capable of calibrating gains of a radiometer array having a plurality of radiometers, comprising:
a plurality of calibration devices, arranged in an array form, wherein each of the calibration devices comprises:
an actuator, configured to receive the calibration signal; and
an MEMS unit, coupled to the actuator, wherein the actuator enables the MEMS unit to shield an antenna of the corresponding radiometer according to the calibration signal, such that the radiometer generates an environmental signal; and
a control unit, configured to output the calibration signal, wherein the control unit normalizes the gains of the radiometers according to the environmental signals.
9. The calibration system as claimed in claim 8, wherein each of the calibration devices further comprises an insulation unit having a groove in which the antenna is disposed.
10. The calibration system as claimed in claim 8, wherein each of the radiometers comprises a low noise amplifier, a power detector and a variable gain amplifier.
11. The calibration system as claimed in claim 8, wherein the radiometers are microwave radiometers.
12. The calibration system as claimed in claim 8, wherein the MEMS unit comprises:
a metal plate, configured to shield the antenna; and
a pushpull bar, having a first terminal and a second terminal respectively coupled to the metal plate and the actuator, such that the metal plate shields the antenna when the actuator pushes or pulls the pushpull bar according to the calibration signal.
13. The calibration system as claimed in claim 8, wherein the MEMS unit comprises:
a gate, having a metal plate, wherein the metal plate shields the antenna when the gate operates in a closed state; and
a torsion beam, coupled between the gate and the actuator to separate the gate and the actuator, such that the gate respectively operates in the closed state and an open state when the actuator respectively operates at a first voltage level and a second voltage level according to the calibration signal.
14. The calibration system as claimed in claim 8, wherein the MEMS unit comprises:
a metal plate, configured to shield the antenna; and
a flexible rod, having a first terminal and a second terminal respectively coupled to the metal plate and the actuator, such that the metal plate shields the antenna when the actuator flexes the flexible rod according to the calibration signal.
15. A calibration method, capable of calibrating gains of a plurality of radiometers, comprising:
shielding antennas of the radiometers of a radiometer array by a plurality of MEMS units according to a calibration signal;
receiving an equivalent radiant temperature from the MEMS units to generate environmental signals; and
normalizing gains of the radiometers according to the environmental signals.
16. The calibration method as claimed in claim 15, further comprising:
disposing each of the antennas of the radiometers in a groove of the corresponding calibration device.
17. The calibration method as claimed in claim 15, wherein each of the radiometers comprises a low noise amplifier, a power detector and a variable gain amplifier.
18. The calibration method as claimed in claim 15, wherein the radiometers are microwave radiometers.
19. The calibration method as claimed in claim 15, further comprising:
pushing or pulling a pushpull bar of each of the MEMS units according to the calibration signal, such that a metal plate of the each of the MEMS units shields the corresponding antenna.
20. The calibration method as claimed in claim 15, further comprising:
opening or closing a gate of each of the MEMS units according to the calibration signal, such that a metal plate of the each of the MEMS unit shields the corresponding antenna.
21. The calibration method as claimed in claim 15, further comprising:
flexing a flexible rod of each of the MEMS units according to the calibration signal, such that a metal plate of the each of the MEMS units shields the corresponding antenna.