1. In a free piston engine comprising:
a housing including a cylinder in its interior;
a first piston installed in the cylinder being allowed to move back and forth in an axial direction of the cylinder;
a second piston installed in the cylinder opposing to the first piston, being allowed to move back and forth in the axial direction and forming a combustion chamber between the first piston and the second piston;
a first and a second biasing units for respectively biasing the first and the second pistons in respective directions so that the first and second pistons move closer to each other;
an intake means for supplying the combustion chamber with mixed gas of air and fuel; and
an exhaust means for exhausting combustion gas of the mixed gas from the combustion chamber,
wherein the mixed gas in the combustion chamber is auto-ignited by being compressed when the first and the second pistons move closer to each other, the first and the second pistons are moved in directions away from each other due to an explosion of the mixed gas, and the first and the second pistons are subsequently moved closer to each other again by biasing forces of the first and the second biasing units, so that a fresh mixed gas is compressed and auto-ignited,
a control device for the free piston engine comprising;
a first drive means for adjusting by a magnetic force a first displacement of the first piston from a first reference position;
a second drive means for adjusting by a magnetic force a second displacement of the second piston from a second reference position;
a detection means for detecting a physical quantity by which a condition of the combustion of the free piston engine can be estimated; and
a displacement control means for controlling, by means of the first and the second drive means, the first and the second displacements with respect to the first and second reference positions according to the detected physical quantity, so that the mixed gas in the combustion chamber is auto-ignited at a timing which is equal to or close to an end of a compression stroke during which the first and second pistons are moved closer to each other.
2. The control device according to claim 1, wherein the physical quantity detected by the detection means comprises at least one of a temperature of the mixed gas, an air-fuel ratio of the mixed gas, and a pressure in the combustion chamber.
3. The control device according to claim 1, wherein,
the first drive means comprises a first linear motor for applying a first thrust power by a magnetic force to the first piston and producing electrical power by transforming a kinetic energy of the first piston to an electric energy,
the second drive means comprises a second linear motor for applying a second thrust power by a magnetic force to the second piston and producing electrical power by transforming kinetic energy of the second piston to electric energy, and
the displacement control means controls the first and the second displacements with respect to the first and second reference positions, by adjusting at least one of the first and the second thrust powers applied to the first and second pistons and oscillation frequencies of the first and the second liner motors.
4. In a free piston engine comprising:
a housing including a cylinder in its interior;
a first piston installed in the cylinder being allowed to move back and forth in an axial direction of the cylinder;
a second piston installed in the cylinder opposing to the first piston, being allowed to move back and forth in the axial direction and forming a combustion chamber between the first piston and the second piston;
a first and a second biasing units for respectively biasing the first and the second pistons in respective directions so that the first and second pistons move closer to each other;
an intake means for supplying the combustion chamber with mixed gas of air and fuel; and
an exhaust means for exhausting combustion gas of the mixed gas from the combustion chamber,
wherein the mixed gas in the combustion chamber is auto-ignited by being compressed when the first and the second pistons move closer to each other, the first and the second pistons are moved in directions away from each other due to an explosion of the mixed gas, and the first and the second pistons are subsequently moved closer to each other again by biasing forces of the first and the second biasing units, so that a fresh mixed gas is compressed and auto-ignited,
a control device for the free piston engine comprising;
a first drive means for adjusting a first displacement of the first piston from a first reference position;
a second drive means for adjusting a second displacement of the second piston from a second reference position;
a detection means for detecting a physical quantity by which a condition of the combustion of the free piston engine can be estimated; and
a displacement control means for controlling, by means of the first and the second drive means, the first and the second displacements with respect to the first and second reference positions according to the detected physical quantity, so that the mixed gas in the combustion chamber is auto-ignited at a timing which is equal to or close to an end of a compression stroke during which the first and second pistons are moved closer to each other.
5. The control device according to claim 4, wherein,
the first drive means comprises a first linear motor for applying a first thrust power by a magnetic force to the first piston and producing electrical power by transforming a kinetic energy of the first piston to an electric energy,
the second drive means comprises a second linear motor for applying a second thrust power by a magnetic force to the second piston and producing electrical power by transforming kinetic energy of the second piston to electric energy, and
the displacement control means controls the first displacement with respect to the first reference position by adjusting at least one of the first thrust power applied to the first piston and an oscillation frequency of the first liner motor, and controls the second displacement with respect to the second reference position by adjusting at least one of the second thrust power applied to the second piston and an oscillation frequency of the second liner motor.
6. In a free piston engine comprising:
a housing including a cylinder in its interior;
a first piston installed in the cylinder being allowed to move back and forth in an axial direction of the cylinder;
a second piston installed in the cylinder opposing to the first piston, being allowed to move back and forth in the axial direction and forming a combustion chamber between the first piston and the second piston;
a first and a second biasing units for respectively biasing the first and the second pistons in respective directions so that the first and second pistons move closer to each other;
an intake means for supplying the combustion chamber with mixed gas of air and fuel; and
an exhaust means for exhausting combustion gas of the mixed gas from the combustion chamber,
wherein the mixed gas in the combustion chamber is auto-ignited by being compressed when the first and the second pistons move closer to each other, the first and the second pistons are moved in directions away from each other due to an explosion of the mixed gas, and the first and the second pistons are subsequently moved closer to each other again by biasing forces of the first and the second biasing units, so that a fresh mixed gas is compressed and auto-ignited,
a method for controlling the free piston engine comprising the steps of;
detecting a physical quantity by which a condition of the combustion of the free piston engine can be estimated; and
controlling, according to the detected physical quantity, displacements of the first and the second pistons from their respective reference positions, so that the mixed gas in the combustion chamber is auto-ignited at a timing which is equal to or close to an end of a compression stroke during which the first and second pistons are moved close to each other.
7. The method according to claim 6, wherein the physical quantity to be detected comprises at least one of a temperature of the mixed gas, an air-fuel ratio of the mixed gas, and a pressure in 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 method for adjusting volume of a mobile device in relationship to environment noise when an incoming call is received by the mobile device, the method comprising:
receiving data communicated to the mobile communication device over a mobile communication network;
designating a first speaker for audibly producing the data communicated to the mobile device;
sampling ambient noise around the mobile device to obtain at least one audio sample, wherein the sampling is performed after the mobile device generates a ring in response to receiving an incoming call;
measuring volume of the ring;
determining the volume of the ambient noise by reducing a measured volume of the at least one audio sample by the volume of the ring;
increasing volume of the first speaker, when the volume of the ambient noise is greater than a first threshold value, so that the data communicated to the mobile device can be produced at a higher audible volume, wherein a user predetermines the first threshold value.
2. The method of claim 1 further comprising:
decreasing the volume of the first speaker, when the volume of the ambient noise is less than at most a second threshold value, so that the data communicated to the mobile device can be produced at a lower audible volume, and wherein the user predetermines the second threshold value.
3. The method of claim 1, wherein the first threshold value represents a first volume beyond which it would be difficult for a user to hear an audio output produced by the mobile device in a first environment.
4. The method of claim 2, wherein the second threshold value represents a second volume above which it would be inappropriate for an audio output of the mobile device to be produced in a second environment.
5. The method of claim 1, wherein the volume of the mobile device is produced by an external speaker of the mobile device.
6. The method of claim 1 wherein the sampling is performed prior to mobile device receiving an incoming call.
7. The method of claim 1 wherein the sampling is performed after mobile device receives an incoming call and before a ring tone is generated by the mobile device.
8. The method of claim 1 wherein the user predetermines a magnitude by which the volume of the first speaker is increased.
9. The method of claim 1, wherein the sampling comprises multiple sampling steps at predetermined time intervals to obtain a plurality of audio samples for the ambient noise.
10. The method of claim 9, wherein the volume of the ambient noise is determined based on the plurality of audio samples obtained.
11. The method of claim 10, wherein the volume of the ambient noise is determined as an average of volumes of the plurality of audio samples obtained.
12. A system for adjusting ring volume of a mobile device when an incoming call is received by the mobile device, the system comprising:
a microphone for obtaining at least one audio sample of ambient noise around the mobile device;
a volume sensor for measuring volume of the at least one audio sample to determine volume of the ambient noise; and
a control mechanism for increasing ring volume of the mobile device, when the volume of the ambient noise is greater than a first threshold value, and for decreasing the ring volume of the mobile device, when the volume of the ambient noise is less than a second threshold value,
wherein a user predetermines the first threshold value and the second threshold,
wherein the user predetermines the magnitude by which the ring volume of the mobile device is adjusted in response to determining the volume of the ambient noise,
wherein the at least one audio sample is obtained after the mobile device generates a ring tone in response to receiving an incoming call; and
wherein the volume of the ambient noise is determined by reducing the measured volume of the at least one audio sample by the volume of the ring tone.
13. The system of claim 12 wherein the at least one audio sample is obtained prior to mobile device receiving an incoming call.
14. The system of claim 12 wherein the at least one audio sample is obtained after the mobile device receives an incoming call and before a ring tone is generated by the mobile device.
15. A system for adjusting speaker volume of a mobile device when an incoming call is received by the mobile device, the system comprising:
a speaker designated for producing audio signals communicated to the mobile device;
a microphone for obtaining at least one audio sample of ambient noise around the mobile device;
a volume sensor for measuring volume of the at least one audio sample to determine volume of the ambient noise; and
a control mechanism for increasing the speaker volume, when the volume of the ambient noise is greater than a first threshold value, and for decreasing the speaker volume of the mobile device, when the volume of the ambient noise is less than a second threshold value, so that the audio signals communicated to the mobile device can be produced at respectively higher and lower audible volumes,
wherein a user predetermines the first threshold value and the second threshold value,
wherein the at least one audio sample is obtained after the mobile device generates a ring tone in response to receiving an incoming call; and
wherein the volume of the ambient noise is determined by reducing the measured volume of the at least one audio sample by the volume of the ring tone.
16. The system of claim 15 wherein the at least one audio sample is obtained prior to mobile device receiving an incoming call.
17. The system of claim 15 wherein the at least one audio sample is obtained after the mobile device receives an incoming call and before a ring tone is generated by the mobile device.