1. A sintered body for thermistor elements comprising Sr, Y, Mn, Al, Fe, and O, wherein crystal phases of a perovskite type oxide, a garnet type oxide, and at least one of a Sr\u2014Al based oxide and a Sr\u2014Fe based oxide are present, and wherein FeYO3 andor AlYO3 is selected as said perovskite type oxide, and at least one compound selected from the group consisting of Y3Al5O12, Al2Fe3Y3O12, and Al3Fe3Y3O12 is selected as said garnet type oxide, respectively by powder X-ray diffraction analysis.
2. The sintered body for thermistor elements according to claim 1, wherein in said perovskite type oxide andor said garnet type oxide, there is Sr solid solution in the Y site, Mn andor Fe solid solution in the Al site, and Al andor Mn solid solution in the Fe site.
3. The sintered body for thermistor elements according to claim 1, wherein when the mole number of Sr is defined as x, the mole number of Y is defined as (1\u2212x), the mole number of Mn is defined as y, the mole number of Al is defined as z, and the mole number of Fe is defined as (1\u2212y\u2212z), wherein x, y, and z have the relationship of 0.090\u2266x\u2266s 0.178, 0.090\u2266y\u22660.178, z\u22670.275, and (1\u2212y\u2212z)\u22670.025.
4. The sintered body for thermistor elements according to claim 1, further comprising Si.
5. The sintered body for thermistor elements according to claim 4, wherein FeYO3 andor AlYO3 is defined as said perovskite type oxide, and at least one compound selected from the group consisting of Y3Al5O12, Al2Fe3Y3O12, and Al3Fe3Y3O12 is selected as said garnet type oxide, by power X-ray diffraction analysis.
6. The sintered body for thermistor elements according to claim 4, wherein in said perovskite type oxide andor said garnet type oxide, there is Sr solid solution in the Y site, Mn andor Fe solid solution in the Al site, and Al andor Mn solid solution in the Fe site.
7. The sintered body for thermistor elements according to claim 4, wherein when the mole number of Sr is defined as x, the mole number of Y is defined as (1\u2212x), the mole number of Mn is defined as y, the mole number of Al is defined as z, and the mole number of Fe is defined as (1\u2212y\u2212z), wherein x, y and z have the relationship of 0.090\u2266x\u2266s 0.178, 0.090\u2266y\u22660.178, z\u22670.275, and (1\u2212y\u2212z)\u22670.025.
8. A process for producing a sintered body for thermistor elements, comprising mixing respective raw material powders containing elemental Sr, Y, Mn, Al, and Fe and calcining the mixture to form a calcined powder; subsequently molding a thermistor forming powder comprising a mixture of the calcined powder with a sintering assistant containing at least elemental Si; and then calcining the resulting molded compact to obtain a sintered body for thermistor element, wherein the sintered body comprises crystal phases of a perovskite type oxide, a garnet type oxide, and at least one of a Sr\u2014Al based oxide and a Sr\u2014Fe based oxide, and
wherein FeYO3 andor AlYO3 is selected as said perovskite type oxide, and at least one compound selected from the group consisting of Y3Al5O12, and Al3Fe3Y3Ol2 is selected as said garnet type oxide, respectively by powder X-ray diffraction analysis.
9. A process for producing a sintered body for thermistor elements, comprising mixing respective raw material powders substantially free from elemental Si and containing elemental Sr, Y, Mn, Al, and Fe, and calcining the mixture to form a calcined powder; subsequently molding the thermistor forming powder obtained by pulverizing the calcined powder; and then calcining the resulting molded compact to obtain a sintered body for thermistor elements, wherein the sintered body comprises crystal phases of a perovskite type oxide, a garnet type oxide, and at least one of a Sr\u2014Al based oxide and a Sr\u2014Fe based oxide, and substantially free from Si, and
wherein FeYO3 andor AlYO3 is selected as said perovskite type oxide, and at least one compound selected from the group consisting of Y3Al5O12, Al2Fe3Y3O12, and Al3Fe3Y3O12 is selected as said garnet type oxide, respectively by powder X-ray diffraction analysis.
10. A thermistor element, which is characterized by using a sintered body for thermistor elements comprising Sr, Y, Mn, Al, Fe, and O, wherein crystal phases of a perovskite type oxide, a garnet type oxide, and at least one of a Sr\u2014Al based oxide and a Sr\u2014Fe based oxide are present, and wherein FeYO3 andor AlYO3 is selected as said perovskite type oxide, and at least one compound selected from the group consisting of Y3Al5O12, Al2Fe3Y3O12, and Al3Fe3Y3O12 is selected as said garnet type oxide, respectively by powder X-ray diffraction analysis.
11. A temperature sensor, which is characterized by using a sintered body for thermistor elements comprising Sr, Y, Mn, Al, Fe, and O, wherein respective crystal phases of a perovskite type oxide, a garnet type oxide, and at least one of a Sr\u2014Al based oxide and a Sr\u2014Fe based oxide are present, and
wherein FeYO3 andor AlYO3 is selected as said perovskite type oxide, and at least one compound selected from the group consisting of Y3Al5O12, Al2Fe3Y3O12, and Al3Fe3Y3O12 is selected as said garnet type oxide, respectively by powder X-ray diffraction analysis.
12. A sintered body for thermistor elements comprising Sr, Y, Mn, Al, Fe and O, wherein crystal phases of a perovskite type oxide, a garnet type oxide, and at least one of a Sr\u2014Al based oxide and a Se\u2014Fe based oide are present, and wherein when the mole number of Sr is defined as x, the mole number of Y is defined as (1\u2212x), the mole number of Mn is defined as y, the mole number of Al is defined as z, and the mole number of Fe is defined as (1\u2212y\u2212z), wherein x, y and z have the relationship of 0.120\u2266x\u22660.166, 0.120\u2266y\u22660.166, 0.494\u2266z\u22660.793, and (1\u2212y\u2212z)\u22670.080.
13. The sintered body for thermistor elements according to claim 12, wherein in said perovskite type oxide andor said garnet type oxide, there is a Sr solid solution in the Y site, a Mn andor Fe solid solution in the Al site, and Al andor Mn solid solution in the Fe site.
14. The sintered body for thermistor elements according to claim 12, which further comprises Si.
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 controlling device for an engine, comprising:
an expansion-ratio adjuster configured to adjust an expansion ratio;
a load detector configured to detect an engine load; and
a controller configured to control the expansion-ratio adjuster on the basis of the engine load detected by the load detector in a manner such that the expansion ratio at the time when the load is below a predetermined load value is set lower than that at the time when the load is equal to the predetermined load value.
2. The controlling device for the engine according to claim 1, wherein the controller is further configured to control the expansion-ratio adjuster in a manner such that the expansion ratio at the time when the load is below the predetermined load value becomes lower as the load decreases.
3. The controlling device for the engine according to claim 1, wherein the predetermined load value is a load value at which a pressure in a cylinder falls below the atmospheric pressure before an exhaust valve opens in a latter half of an expansion process.
4. The controlling device for the engine according to claim 1, wherein the expansion-ratio adjuster includes an exhaust valve opening-timing adjuster configured to adjust an opening timing of an exhaust valve, and
wherein when the load is below the predetermined load value, the controller advances the opening timing of the exhaust valve so as to reduce the expansion ratio.
5. The controlling device for the engine according to claim 4, wherein the exhaust valve opening-timing adjuster adjusts only the opening timing of the exhaust valve.
6. The controlling device for the engine according to claim 4, wherein the exhaust valve opening-timing adjuster advances a closing timing of the exhaust valve by the advanced amount of the opening timing of the exhaust valve.
7. The controlling device for the engine according to claim 6, wherein the expansion-ratio adjuster further includes an intake valve opening-timing adjuster configured to adjust an opening timing of an intake valve, and
wherein when the load is below the predetermined load value, the controller advances the opening timing of the intake valve together with advancing the opening and closing timings of the exhaust valve.
8. The controlling device for the engine according to claim 1, wherein the expansion-ratio adjuster includes a top-dead-center position adjusting mechanism configured to adjust a top-dead-center position of a piston, and
wherein when the load is below the predetermined load value, the controller lowers the top-dead-center position of the piston so as to reduce the expansion ratio.
9. The controlling device for the engine according to claim 8, wherein the top-dead-center position adjusting mechanism comprises a plurality of links that link the piston to a crankshaft, and
wherein the expansion ratio is reduced by regulating the movement of at least one of the links.
10. The controlling device for the engine according to claim 9, wherein the plurality of links comprises:
a first link connected to the piston by means of a piston pin;
a second link rockably connected to the first link and rotatably connected to the crankshaft; and
a third link which is rockably connected to the second link and regulates the rocking of the second link.
11. The controlling device for the engine according to claim 8, wherein the piston has stroke characteristics that are substantially a simple harmonic motion.
12. The controlling device for the engine according to claim 8, wherein a stroke amount of the piston is greater than the diameter of the piston.
13. The controlling device for the engine according to claim 4, wherein the expansion-ratio adjuster further includes an intake valve closing-timing adjuster configured to adjust a closing timing of an intake valve, and
wherein the controller sets a closing timing of the intake valve prior to a bottom dead center point and advances a closing timing of the intake valve as the load decreases.
14. The controlling device for the engine according to claim 1, wherein the expansion-ratio adjuster includes an exhaust-valve opening-timing adjuster configured to adjust an opening timing of an exhaust valve and a top-dead-center position adjusting mechanism configured to adjust a top-dead-center position of a piston, and
wherein when the load is below the predetermined load value, the controller reduces the expansion ratio by means of the exhaust valve opening-timing adjuster.
15. A method for controlling an engine, comprising the steps of:
detecting an engine load; and
controlling an expansion ratio of the engine on the basis of the detecting step in a manner setting lower the expansion ratio at the time when the load is below a predetermined load value than that at the time when the load is at least equal to the predetermined load value.