Abstract: In a laser ignition apparatus, a focusing optical element is configured to focus a pulsed laser light to a predetermined focal point in a combustion chamber of an engine. An optical window member is arranged on the combustion chamber side of the focusing optical element so as to separate the focusing optical element from the combustion chamber. A catoptric-light focal point, at which a catoptric light is to be focused, is positioned on the anti-combustion chamber side of a combustion chamber-side end surface of the optical window member. The catoptric light results from the reflection of the pulsed laser light by a pseudo mirror that is formed by the optical window member when the combustion chamber-side end surface thereof is fouled with contaminants. Further, the catoptric-light focal point falls in a region where no solid material forming either the focusing optical element or the optical window member exists.

Abstract: A laser ignition apparatus includes a housing that has a male-threaded portion for fixing the housing and a hexagonal portion for tightening the male-threaded portion. Between a combustion chamber-side end of the male-threaded portion and an anti-combustion chamber-side end of the hexagonal portion, there is defined a non-optical element arrangement region in which none of an introducing optical element, an enlarging optical element and a focusing optical element of the apparatus is arranged. At one of a combustion chamber-side end and an anti-combustion chamber-side end of the non-optical element arrangement region, there is formed a reference surface that extends perpendicular to an axial direction of the housing. One of the introducing optical element, the enlarging optical element and the focusing optical element is received in the housing in such a manner as to be elastically pressed against the reference surface from outside of the non-optical element arrangement region.

Abstract: A sealing structure seals a clearance between a housing and a brake rotor. The housing defines a fluid chamber for sealing a magnetic viscous fluid inside. The brake rotor penetrates through the housing and generates brake torque by contacting the magnetic viscous fluid. The housing has a magnetic sleeve section and a magnetic screw section provided to the brake rotor. The magnetic sleeve section is continuous in a rotational direction of the brake rotor and generates a magnetic flux. The magnetic screw section is an external screw having a screw thread, which extends away from a fluid chamber side toward a phase adjusting mechanism side when traced in a rotational direction of the brake rotor. The magnetic flux is guided to the magnetic screw section through a sealing gap between the magnetic screw section and an inner peripheral section of the magnetic sleeve section.

Abstract: A variable valve timing apparatus has a case, a rotor, and a magneto-rheological fluid. The magneto-rheological fluid gives variable braking force to the rotor. The rotor is connected with a phase adjusting mechanism. The phase adjusting mechanism adjusts a phase of an internal combustion engine according to braking force. A sealing device is disposed between the case and the rotor. In one embodiment, the sealing device has a magnet and a plurality of flux guide members. In other embodiment, a diaphragm which acts as a damper mechanism for absorbing an internal pressure change is disposed on a fluid chamber in which the magneto-rheological fluid is kept.

Abstract: A sealing structure seals a clearance between a housing and a brake rotor. The housing defines a fluid chamber for sealing a magnetic viscous fluid inside. The brake rotor penetrates through the housing and generates brake torque by contacting the magnetic viscous fluid. The housing has a magnetic sleeve section and a magnetic screw section provided to the brake rotor. The magnetic sleeve section is continuous in a rotational direction of the brake rotor and generates a magnetic flux. The magnetic screw section is an external screw having a screw thread, which extends away from a fluid chamber side toward a phase adjusting mechanism side when traced in a rotational direction of the brake rotor. The magnetic flux is guided to the magnetic screw section through a sealing gap between the magnetic screw section and an inner peripheral section of the magnetic sleeve section.

Abstract: A valve timing adjusting apparatus for an engine includes a casing, magnetorheological fluid, a control device, a brake rotor, a phase adjustment mechanism, and a sealing structure. The control device changes the degree of viscosity of magnetorheological fluid in the casing. The sealing structure seals a gap between the casing and the brake rotor. The sealing structure includes an annular permanent magnet and at least one annular magnetic flux guide. The at least one magnetic flux guide defines a guide gap between the at least one magnetic flux guide and the other one of the casing and the brake rotor. The direction of magnetic flux relative to an axial center of the brake rotor, which flux is generated by the control device is similar to a direction of magnetic flux relative to the axial center generated by the permanent magnet.

Abstract: A variable valve timing apparatus has a case, a rotor, and a magneto-rheological fluid. The magneto-rheological fluid gives variable braking force to the rotor. The rotor is connected with a phase adjusting mechanism. The phase adjusting mechanism adjusts a phase of an internal combustion engine according to braking force. A sealing device is disposed between the case and the rotor. In one embodiment, the sealing device has a magnet and a plurality of flux guide members. In other embodiment, a diaphragm which acts as a damper mechanism for absorbing an internal pressure change is disposed on a fluid chamber in which the magneto-rheological fluid is kept.

Abstract: An ejector pump is provided which works to use dynamic energy of a jet of a main fluid emitted from a nozzle to suck a sub-fluid therein. When it is required to stop the ejector pump, the needle is moved to bring a sealing surface formed on a head thereof into abutment with a sealing surface formed around a main fluid flow path extending inside the ejector pump to close the main fluid flow path, thereby inhibiting the fluid pressure from acting on any downstream device. Upon the abutment, the needle is kept away from a nozzle, thereby avoiding undesirable wear or deformation of the needle and nozzle.

Abstract: A fuel cell system is provided which includes a fluid pump such as an ejector pump. The fluid pump is designed to be driven by energy of air flowing within an air line through which air is supplied to a fuel cell. The fluid pump works to suck a fluid containing drops of water and residual gasses from the hydrogen line, thereby ensuring desired startability and stability of operation of the fuel cell.

Abstract: A fuel cell system performing a pre-process for electric generation in a fuel cell controls at least one of a flow amount of fuel gas flowing through a fuel gas supply path and a flow amount of off gas flowing through an off gas circulation path in order to regulate a circulation ratio of a mixed gas composed of the fuel gas and the off gas. The circulation ratio is a ratio between a mole flow amount of the off gas to a mole flow amount of the fuel gas. Before initiating usual electric generation of the fuel cell, the fuel cell system performs the pre-process in which the fuel gas is supplied to the fuel cell in order to set the circulation ratio within a predetermined range. The lower limit of the circulation ratio is set to a value by which all initial gas in a fuel electrode of the fuel cell before initiating the pre-process is exhausted completely.

Abstract: A fuel cell system is provided which includes an off-gas recirculating mechanism working to mix an off-gas discharged from a fuel cell with a hydrogen gas supplied to the fuel cell. The off-gas recirculating mechanism is implemented by an ejector vacuum pump which is controllable of an area of an outlet thereof to bring an output pressure into agreement with a target one. Use of such a type of ejector vacuum pump ensures desired accuracy of recirculation of the off-gas and regulation of the pressure of fuel supplied to the fuel cell.

Abstract: A fuel cell system with a fuel cell (FC stack) has an off gas circulation path to the fuel cell, an off gas exhaust unit, and an off gas pressure sensor. The system measures physical properties such as a pressure and temperatures of the off gas at various timings before and after the purging, and the calculator in the system calculates an off gas density and a hydrogen concentration in the off gas based on the measured physical properties. The system determines optimum conditions such as a start-up time and an operation period of time for the purging based on the measured and calculated values.

Abstract: A fuel supply system for use in a fuel cell system which includes a controller, a pressure regulator, and an ejector device. The controller controls the pressure of a main flow of fuel gas outputted from the pressure regulator and the position of an ejector nozzle of the ejector vacuum pump as a function of electricity generated by a fuel cell to adjust a flow rate of an off-gas to be recirculated to the fuel cell. This structure eliminates the need for an additional flow regulator to regulate the flow rate of the off-gas, thereby ensuring the stability in controlling the flow rate of the off-gas to be recirculated.

Abstract: Provided is a fuel cell system capable of activating a fuel cell even under low-temperature environments. The fuel cell system detects an outside air temperature in the vicinity of the fuel cell to, after the fuel cell enters a deactivated state, estimate a transition of outside air temperature on the basis of a variation of the detected outside air temperature, and makes a decision as to whether or not the estimated outside air temperature falls below a predetermined freezing temperature at which moisture freezes. When a decision is made that the estimated outside air temperature falls below the predetermined freezing temperature, freezing prevention processing is conducted to prevent moisture from freezing in the interior of the fuel cell. The estimation of the outside air temperature transition is made by time-differentiating a variation of outside air temperature.

Abstract: An ejector pump is provided which works to use dynamic energy of a jet of a main fluid emitted from a nozzle to suck a sub-fluid therein. When it is required to stop the ejector pump, the needle is moved to bring a sealing surface formed on a head thereof into abutment with a sealing surface formed around a main fluid flow path extending inside the ejector pump to close the main fluid flow path, thereby inhibiting the fluid pressure from acting on any downstream device. Upon the abutment, the needle is kept away from a nozzle, thereby avoiding undesirable wear or deformation of the needle and nozzle.

Abstract: Under a condition that a main stream hydrogen amount fed into a fuel cell is constant, an off-gas circulation amount and a hydrogen concentration of the circulated off-gas are in a predetermined relationship. Considering this relationship, the hydrogen concentration of the circulated off-gas can be obtained by detecting the main stream hydrogen amount and the off-gas circulation amount. The impurities contained in the circulated off-gas are chiefly nitrogen. The nitrogen concentration of the circulated off-gas is inverse proportional to the hydrogen concentration. The nitrogen concentration (i.e., impurity concentration) is obtainable by detecting the hydrogen concentration. Increase of impurities contained in the circulated off-gas is detectable in advance based on the main stream hydrogen amount and the off-gas circulation amount. The impurities can be removed before the output of the fuel cell becomes unstable. The fuel cell operates stably.

Abstract: A fuel cell system is provided which includes a fluid pump such as an ejector pump. The fluid pump is designed to be driven by energy of air flowing within an air line through which air is supplied to a fuel cell. The fluid pump works to suck a fluid containing drops of water and residual gasses from the hydrogen line, thereby ensuring desired startability and stability of operation of the fuel cell.

Abstract: A fuel cell system is provided which includes an off-gas recirculating mechanism working to mix an off-gas discharged from a fuel cell with a hydrogen gas supplied to the fuel cell. The off-gas recirculating mechanism is implemented by an ejector vacuum pump which is controllable of an area of an outlet thereof to bring an output pressure into agreement with a target one. Use of such a type of ejector vacuum pump ensures desired accuracy of recircualtion of the off-gas and regulation of the pressure of fuel supplied to the fuel cell.

Abstract: Provided is a fuel cell system capable of activating a fuel cell even under low-temperature environments. The fuel cell system detects an outside air temperature in the vicinity of the fuel cell to, after the fuel cell enters a deactivated state, estimate a transition of outside air temperature on the basis of a variation of the detected outside air temperature, and makes a decision as to whether or not the estimated outside air temperature falls below a predetermined freezing temperature at which moisture freezes. When a decision is made that the estimated outside air temperature falls below the predetermined freezing temperature, freezing prevention processing is conducted to prevent moisture from freezing in the interior of the fuel cell. The estimation of the outside air temperature transition is made by time-differentiating a variation of outside air temperature.

Abstract: A tube is provided with elastically deformable tube deforming sections (tube curved sections), and a fin is provided with the quality of spring so that the fin deforms in accordance to changes of dimension between the tubes. Accordingly, it is possible to weaken (absorb) stress by the tube deforming sections (tube curved sections), and to prevent the fin from separating from the tube even when the tube deforming section (tube curved section) deforms.