Abstract: A dilator (30) insertable into a catheter (20) includes a tubular shaft part (40), and a tubular flexible part (50) located on a distal end side of the shaft part (40) and formed of a resin more flexible than the shaft part (40), and includes, in the shaft part (40) and/or the flexible part (50), a physical property inclined part (42) in which rigidity gradually decreases from a proximal end side toward a distal end side. The catheter assembly is capable of achieving both stable catheter insertability into a blood vessel and reduction in risk of blood vessel perforation.

Abstract: Apparatus for detecting the NOx concentration includes a first measurement chamber 20 communicating with the gas under measurement via a diffusion rate defining layer 4d and a second measurement chamber 26 communicating with the first measurement chamber 20 via diffusion limiting layers 6d, 22d. A first pump current IP1 is controlled so that an output of a Vs cell 6 will be equal to the reference voltage VCO for controlling the oxygen concentration in the first measurement chamber 20 to a pre-set low value. A constant voltage is applied across the second pump cell 8 for decomposing the NOx component in the second measurement chamber 26 for pumping out oxygen for detecting the NOx concentration from a second pump current IP2. The sensor temperature is detected from the internal resistance of the Vs cell for controlling the current supplied to the heaters 12, 14. If the temperature of the gas under measurement is changed rapidly, the sensor temperature is changed.

Abstract: Apparatus for detecting the NOx concentration includes a first measurement chamber 20 communicating with the gas under measurement via a diffusion rate defining layer 4d and a second measurement chamber 26 communicating with the first measurement chamber 20 via diffusion limiting layers 6d, 22d. A first pump current IP1 is controlled so that an output of a Vs cell 6 will be equal to the reference voltage VCO for controlling the oxygen concentration in the first measurement chamber 20 to a pre-set low value. A constant voltage is applied across the second pump cell 8 for decomposing the NOx component in the second measurement chamber 26 for pumping out oxygen for detecting the NOx concentration from a second pump current IP2. The sensor temperature is detected from the internal resistance of the Vs cell for controlling the current supplied to the heaters 12, 14. If the temperature of the gas under measurement is changed rapidly, the sensor temperature is changed.

Abstract: Apparatus for detecting the NOx concentration includes a first measurement chamber 20 communicating with the gas under measurement via a diffusion rate defining layer 4d and a second measurement chamber 26 communicating with the first measurement chamber 20 via diffusion limiting layers 6d, 22d. A first pump current IP1 is controlled so that an output of a Vs cell 6 will be equal to the reference voltage VCO for controlling the oxygen concentration in the first measurement chamber 20 to a pre-set low value. A constant voltage is applied across the second pump cell 8 for decomposing the NOx component in the second measurement chamber 26 for pumping out oxygen for detecting the NOx concentration from a second pump current IP2. The sensor temperature is detected from the internal resistance of the Vs cell for controlling the current supplied to the heaters 12, 14. If the temperature of the gas under measurement is changed rapidly, the sensor temperature is changed.

Abstract: A method and apparatus for detecting a functional condition of an NOx occlusion catalyst using an NOx sensor. In order to compensate for variations in oxygen concentration of the exhaust gas which would otherwise affect the detected NOx concentration downstream of the NOx occlusion catalyst, a relative value is calculated as the difference between the detected NOx concentration and the value of the detected NOx concentration initially after start of operation control of an internal combustion engine at a lean air-fuel ratio. The occlusion capability of the NOx occlusion catalyst is judged to have deteriorated when an increase in the relative value exceeds a predetermined value. On the other hand, the NOx occlusion catalyst is judged to have suffered an anomaly when the rate of increase in the relative value becomes greater than a predetermined allowable value.

Abstract: Apparatus for detecting the NOx concentration includes a first measurement chamber 20 communicating with the gas under measurement via a diffusion rate defining layer 4d and a second measurement chamber 26 communicating with the first measurement chamber 20 via diffusion limiting layers 6d, 22d. A first pump current IP1 is controlled so that an output of a Vs cell 6 will be equal to the reference voltage VCO for controlling the oxygen concentration in the first measurement chamber 20 to a pre-set low value. A constant voltage is applied across the second pump cell 8 for decomposing the NOx component in the second measurement chamber 26 for pumping out oxygen for detecting the NOx concentration from a second pump current IP2. The sensor temperature is detected from the internal resistance of the Vs cell for controlling the current supplied to the heaters 12, 14. If the temperature of the gas under measurement is changed rapidly, the sensor temperature is changed.

Abstract: Apparatus for detecting the NOx concentration includes a first measurement chamber 20 communicating with the gas under measurement via a diffusion rate defining layer 4d and a second measurement chamber 26 communicating with the first measurement chamber 20 via diffusion limiting layers 6d, 22d. A first pump current IP1 is controlled so that an output of a Vs cell 6 will be equal to the reference voltage VCO for controlling the oxygen concentration in the first measurement chamber 20 to a pre-set low value. A constant voltage is applied across the second pump cell 8 for decomposing the NOx component in the second measurement chamber 26 for pumping out oxygen for detecting the NOx concentration from a second pump current IP2. The sensor temperature is detected from the internal resistance of the Vs cell for controlling the current supplied to the heaters 12, 14. If the temperature of the gas under measurement is changed rapidly, the sensor temperature is changed.

Abstract: An NOx sensor capable of accurately determining the concentration of NOx contained in a gas to be analyzed (measurement gas) using a simple circuit. The NOx sensor includes a first measurement space and a second measurement space. The first measurement space communicates with the measurement gas via a first diffusion controlling layer, and the second measurement space communicates with the first measurement space via a second diffusion controlling layer. A first pumping current IP1 is controlled such that an output from a Vs cell is used as a reference voltage VC0 to control the amount of oxygen flowing into the second measurement space at a constant level. A constant voltage is applied to the second pumping cell so as to decompose the NOx component of the measurement gas contained in the second measurement space, and to pump out the resulting oxygen from the second measurement space. Accordingly, the concentration of NOx contained in the measurement gas can be obtained from second pumping current IP2.

Abstract: An ion current detection apparatus which can detect ion current with a high degree of accuracy regardless of the presence of voltage damped oscillation and which does not cause contamination of a spark plug. A spark discharge current Isp generated upon spark discharge of a spark plug 10 flows through a charge diode 28, a capacitor 24, and a diode 22, which form a closed loop together with the spark plug 10 and a secondary winding L2 of an ignition coil 12 that constitutes an ignition apparatus. As a result, a Zener diode 26 connected in parallel to these components generates a Zener voltage Vz and thereby charges the capacitor 24. When a preset wait time has elapsed after the ignition timing for starting spark discharge, the discharge switch 30 short-circuits the opposite ends of the charge diode 28 to discharge the capacitor 24, so that a high voltage having a polarity opposite that in the case of spark discharge is applied to the spark plug.

Abstract: Using a sole Nox sensor Nox concentration and oxygen concentration are measured accurately. A measurement device for measuring NOx concentration and oxygen concentration comprises an NOx sensor 2 having a first measurement chamber 20 communicating via a diffusion rate regulating layer 4d with the gas under measurement and a second measurement chamber 26 communicating with the first measurement chamber 20 via diffusion rate regulating layers 6d, 22d. A first pump cell 4 and an oxygen concentration measurement Vs cell 6 are formed on the first measurement chamber 20, while a second pump cell 8 is formed on the second measurement chamber 26. Inside of the first measurement chamber 20 is controlled to a constant low oxygen concentration by controlling the first pump current IP1 so that output of Vs cell 6 will equal a reference voltage VC0. By applying a constant voltage across the second pump cell 8 NOx in the second measurement chamber 26 is decomposed to pump out oxygen.

Abstract: An air/fuel ratio detection device and an air/fuel ratio control device, in which combustion of an engine is controlled with a simple design and toxic substances in exhaust gas discharged from the engine are reduced. Time A during which a lean signal is at a high level is measured. If the time A is shorter than the predetermined value, it is determined that the air/fuel ratio is richer than a target value, and time B during which an electromagnetic valve 21 is open is lengthened, increasing the quantity of supply air and making leaner the fuel mixed air, such that the target air/fuel ratio is approached. If the time A is longer than the predetermined value, it is determined that the air/fuel ratio is leaner and the time B is shortened.

Abstract: An air/fuel ratio sensor is controlled such that the oxygen concentration of the measurement gas can be detected from a pump current substantially instantaneously after a heater turns on. In the air/fuel ratio sensor an oxygen pumping cell and an oxygen concentration measuring cell are each formed of a solid electrolytic layer interposed between a pair of porous electrodes. One of the electrodes of each cell defines a measurement gas chamber in which the diffusion of the measurement gas is controlled. After a micro current is supplied to the other electrode of the oxygen concentration measuring cell for a predetermined period of time, thereby forming an internal reference oxygen source, the supply of the micro current is stopped and at the same time a pump current in the oxygen pumping cell starts to be controlled until the interelectrode voltage of the oxygen concentration measuring cell reaches a target voltage. After the air/fuel ratio sensor is activated, the supply of the micro current is restarted.

Abstract: A misfire detecting device for an ignition system, comprises high voltage applying means for applying a pulsed high voltage to each spark plug of an engine after completion of firing of the spark plug, voltage restricting means for restricting a peak of the pulsed high voltage to a highest possible value that does not cause firing of the spark plug, voltage detecting means for detecting a plug voltage across a center electrode-to-outer electrode of the spark plug after reducing the same, and misfire detecting means for detecting a misfire at each cylinder on the basis of a decay characteristic of a detection voltage which is caused by application of the pulsed high voltage.

Abstract: A method of detecting a misfire of an ignition system for an internal combustion engine is provided. By the method, after completion of spark discharge of a spark plug, a high tension pulse which is not so high as to cause spark discharge is applied to each spark plug by way of a reverse current preventing diode and a secondary winding of an ignition coil or by way of a reverse current preventing diode and a leakage preventing diode for preventing ingress of an ignition high voltage. Misfire at each cylinder is detected on the basis of a voltage attenuation characteristic at a passing side terminal of the reverse current preventing diode. A device for carrying out the above method is also provided.

Abstract: A misfire detecting device for an ignition system, comprises high voltage applying device for applying a pulsed high voltage to each spark plug of an engine after completion of firing of the spark plug, voltage restricting device for restricting a peak of the pulsed high voltage to a highest possible value that does not cause firing of the spark plug, voltage detecting component for detecting a plug voltage across a center electrode-to-outer electrode of the spark plug after reducing the same, and misfire detecting device for detecting a misfire at each cylinder on the basis of a decay characteristic of a detection voltage which is caused by application of the pulsed high voltage.

Abstract: In a spark plug voltage probe device which detects a voltage applied to a spark plug installed in an internal combustion engine so as to analyze a burning condition in the internal combustion engine on the basis of the voltage applied to the spark plug, a rubber clamper (9) is secured to the internal combustion engine, and having a groove (92) in which a spark cable (60) is located so as to form a static capacity between the rubber clamper (9) and the spark plug cable (60). An electrical conductor (93) is embedded in the rubber clamper (9) along the groove (92) while the electrical conductor (93) is connected to a microcomputer by way of an output cable (64) so as to analyze a spark plug voltage waveform. A condenser (42) is connected to a common point (A) between the electrical conductor (93) and the microcomputer so as to reduce the spark plug voltage according to a capacity of the condenser (42).

Abstract: In a sparkplug voltage probe device in use for an internal combustion engine, an insulator base is attached to the internal combustion engine, an upper surface of the insulator base having a plurality of grooves in which the sparkplug cables are placed. An insulator sheet is embedded in the insulator base. An electrode layer is provided on an upper surface of the insulator base along the grooves to form a static capacity between the electrode layer and the sparkplug cables when the voltage is applied across the spark plugs. On a lower surface of the insulator sheet an electrical shield layer is provided connected to the internal combustion engine by a ground wire. A lead wire electrically connects the electrode plate to a microcomputer so as to analyze the engine burning condition based on the static capacity between the electrode plate and the sparkplug cables.

Abstract: A misfire detecting device for a double-ended distributorless ignition system is provided. The device includes a pulse generating circuit for generating a positive polarity pulse which is not so high as to cause spark discharge during the time after completion of spark discharge and before beginning of application of an ignition high voltage for next spark discharge. A reverse current preventing diode is connected at an anode to an output end of the pulse generating circuit and at a cathode to a positive polarity side of a secondary winding of an ignition coil. A plug voltage dividing circuit for dividing a plug voltage is connected between a center electrode and an outer or ground electrode of each of spark plugs to obtain a divided voltage. A detecting circuit detects a misfire of the spark plugs on the basis of an attenuation characteristic of the divided voltage after application of the positive polarity pulse.

Abstract: In a sparkplug voltage probe device, an insulator base is attached to the internal combustion engine, an upper surface of the insulator base having a plurality of grooves in which the corresponding cables are placed. An electrode plate is embedded in the insulator base along the grooves to form a static capacity between the electrode plate and an array of all the cables in the grooves, both of the longitudinal sides of the electrode plate being curled around the outermost cables respectively to compensate shortage of static capacitance so as to form a capacitance adjusting function in order to substantially even a distribution of the static capacity between the electrode plate and the array of all the cables in a direction perpendicular to a length of the electrode plate. A lead wire is provided to electrically connect the electrode plate to a microcomputer.

Abstract: In a spark plug voltage probe device which detects voltage applied to a spark plug installed in an internal combustion engine so as to analyze burning conditions in the internal combustion engine on the basis of the voltage applied to the spark plug, a rubber collar (74) is provided to surround rubber cap (7) secured to high tension terminal (71a) of spark plug (71) so as to form a static capacity between high tension terminal (71a) and rubber collar (74). Electrical conductor (73) is provided between rubber cap (7) and rubber collar (74), and conductor (73) is electrically connected to a microcomputer by output cable (64) so as to analyze the spark plug voltage waveform. Condenser (42) is connected at one end to the ground and the other end to a common point (A) between electrical conductor (73) and the microcomputer so as to reduce the spark plug voltage according to the capacity of condenser (42).