Denso Corporation

Denso Corpora Tion

Go Miyagawa

Masayuki Tamura

Masahiro Yamamoto

Kazuhiko Koike

Takashi Araki

Manabu Yoshidome

Masato Katsuno

Toshihiro Sakawa

Hironobu Shimokawa

Hirokatsu Imagawa

Kensuke Takizawa

Tomotaka Mouri

Takehito Kimata

Takao Mishima

Kouji Andoh

Toru Katafuchi

Yuto Tamei

Hideki Yamada

Failure detection apparatus for a particulate filter includes: a sensor having a particulate matter detection unit that outputs a signal corresponding to the amount of accumulated PM, and a heater unit that heats the particulate matter detection unit; a regeneration control unit that causes the heater unit to heat the particulate matter detection unit to a regeneration temperature allowing the particulate matter to be burned off; a start detection unit that determines the start of the internal combustion engine; failure determination unit that determines whether exhaust gas contains water droplets while the engine is in operation; a heating control unit that causes the heater unit to heat the particulate matter detection unit to a first temperature allowing the accumulated particulate matter to remain and the moisture included in the particulate matter to be removed; and failure determination unit that determines whether the filter has failure based on a sensor output value.

Failure detection apparatus and failure detection method for particulate filter

A PM detection sensor has a sensor body part made of an insulating member and a positive electrode and a negative electrode. The positive electrode is composed of a plurality of positive electrode segments. The negative electrode is composed of a plurality of negative electrode segments. A deposition surface is formed on the sensor body part. These electrode segments are formed on the deposition surface to be exposed to exhaust gas introduced into the inside of the PM detection sensor. The positive electrode segments and the negative electrode segments are arranged adjacently to and separately from each other, on the deposition surface, along a short width direction and a long width direction of each electrode segment. The short width direction and the long width direction are orthogonal to a normal direction of the deposition surface.

Particulate matter detection sensor

After an engine is started, an ECU performs first regeneration processing of a PM sensor through heating by a heater and, after the first regeneration processing, applies a voltage continuously to detection electrodes for a predetermined voltage application period. The ECU causes PM to adhere to an insulating substrate due to the voltage application and, at a time point after the predetermined time period has elapsed, determines the amount of PM that is adhering to the insulating substrate. When a predetermined condition is satisfied outside the voltage application period, the ECU determines whether the amount of adhering PM on the insulating substrate is equal to or greater than an excess determination threshold value. If the amount of adhering PM is determined to be equal to or greater than the excess determination threshold value, the ECU performs second regeneration processing of the PM sensor, through heating by the heater.

Sensor control apparatus

A failure detection device has a PM filter, a PM detection sensor having a sensor element arranged at a downstream of the PM filter, an ECU and a PM detection sensor control part. The sensor element detects an amount of PM in exhaust gas, and generates a sensor signal corresponding to the detected PM amount. A load detection part in the ECU detects an engine load. A judgment execution determination part in the control part compares the detected engine load with a threshold value, and determines whether a PM filter failure detection should be performed based on the comparison result. A failure judgment part compares the sensor signal with a failure judgment threshold value when the determination part decides that it is necessary to perform the failure detection of the PM filter, and determines that the PM filter failure has occurred based on the latter comparison result.

Failure detection device for particulate matter filter and method of detecting failure of particulate matter filter

An apparatus which detects particulate matter is provided. This apparatus estimates a volume of water inside an exhaust passage using estimation sections. When an estimated volume of water is larger than a water drainage threshold, an element portion is heated using a heater by the first temperature range controller, in a temperature range which resists water-induced cracking independent of a volume of water droplets. If the estimated volume of water is less than a water drainage threshold, the water drainage determination section determines that the water drainage of the exhaust passage is completed. Additionally, if it is estimated that the water drainage is completed, the element portion is heated by a second temperature controller at temperature lower than a starting temperature of combustion of particulate matter and in order to repel water adhered onto the element portion in a water-repellent temperature range for a predetermined period.

Particulate matter detection apparatus that mitigates water collection

A particulate matter detecting device includes: an element unit on which particulate matter contained in exhaust gas from an internal combustion engine is deposited; a heater that heats the element unit; a detecting unit that detects the amount of particulate matter on the basis of electrical characteristics of the element unit; and a control unit that controls the operation of the heater. For a predetermined period that does not include a period in which the particulate matter is deposited on the element unit, the control unit operates the heater using a predetermined amount of control set in advance such that the temperature of the element unit is higher than the temperature of the exhaust gas and lower than a predetermined temperature at which the element unit is thermally degraded.

Particulate matter detecting device

A particulate matter sensor and a particulate matter sensing system using such a sensor are provided which are capable of being produced at decreased cost and accurately measuring the temperature of a heater. The particulate matter sensor includes a deposition portion on which particulate matter contained in exhaust gas is accumulated, a pair of electrodes which are disposed on the deposition portion and separate from each other, a heater which heats the deposition portion, and a pair of heater leads which form a path through which electrical current is delivered to the heater. A sensing line is connected to at least one of the heater leads to measure a resistance of the heater lead.

Particulate matter sensor and particulate matter sensing system

A sensor element which has a pair of positive and negative detection electrodes disposed on a surface of an insulation body as a detecting portion and a cover body configured to cover an opening of a cylindrical housing. The cover body is provided with gas inlet and outlet holes via which the measuring gas is introduced and discharged. The pair of detection electrodes have a plurality of wire electrodes. The wire electrodes electrically connected to the positive electrode and the wire electrodes electrically connected to the negative electrode are alternately arranged in parallel. Any one of a first insulation layer which is a narrow electrode interval Dn and a second insulation layer which is a wide electrode interval Dw, arranged between adjacent wire electrodes, and the first insulation layer arranged in a center part of the detecting portion.

The particulate matter detection sensor includes a conductive part, and the pair of electrodes that are arranged at specified spacing so as to face each other. The conductive part is formed into a plate shape using a conductive material having electrical resistivity that is higher than particulate matter. One major surface of the conductive part functions as an accumulation surface on which particulate matter accumulates. The pair of electrodes are formed on this accumulation surface.

Particulate matter detection sensor and particulate matter detection apparatus

A particulate matter detection apparatus is provided with an element portion onto which PM contained in exhaust gas of an engine adheres thereto. A heater which heats the element portion, a quantity detecting portion which detects a quantity of the PM based on electrical properties of the element portion and a temperature detecting portion which detects a temperature of the element portion. The apparatus is further provided with a first and second temperature controller. The first temperature controller heats the element portion using a heater in a first period, which excludes a period in which PM adheres to the element portion based on a detected temperature of the element portion. The element portion is heated in a first temperature range to combust soluble organic fractions contained in the PM and resist melting of ash components contained in the PM. The first period excludes a period in which PM adheres to the element portion. The second temperature controller heats the element portion in the second temperature range, which is higher than the first temperature range using the heater, such that ash is combusted, based on a detected temperature of the element portion.

Particulate matter detection apparatus

A filter malfunction determination apparatus includes a calculator that calculates, upon determination that a rapid output increase has occurred, an amount of change of a parameter value output from a sensor before and after the rapid output increase. The calculator calculates, based on the calculated amount of change, a correction value for correcting at least one of the parameter value output from the sensor and a malfunction determination threshold. The filter malfunction determination apparatus includes an offset corrector configured to perform, based on the correction value, offset correction of at least one of the parameter value output from the sensor and the malfunction determination threshold after determination that the rapid output increase has occurred.

Apparatus for determining whether there is malfunction in filter device

A particulate matter detection sensor has an accumulation section for accumulating a part of particulate matter particles contained in exhaust gas emitted from an internal combustion engine, and a pair of a first detection electrode and a second detection electrode formed on the accumulation section. The second detection electrode is formed separated from the first detection electrode. The first detection electrode has projecting parts which project toward the second detection electrode. Because a separation between the first and second detection electrodes is locally reduced at the projecting parts, the projecting parts attract and accumulate more particulate matter, and this structure makes it possible to allow the particulate matter detection sensor to have improved detection sensitivity.

A particulate matter detection elementincludes paired detection electrodesfor detecting particulate matter contained in exhaust gas discharged from an internal combustion engine, and insulating membermade of electrically insulating material. In the particulate matter detection element, at least part of the paired detection electrodesis exposed from the insulating memberin the direction perpendicular to the lamination direction of the paired detection electrodes, to cause part of the particulate matter to deposit thereon. The surface roughness of at least the insulating member disposed between the paired detection electrodes is between 0.8 &#x3bc;m and 8.0 &#x3bc;m in 10-point average roughness.

Particulate matter detection element and particulate matter detection sensor

A particulate matter detection sensor has an element part for detecting an amount of PM contained in exhaust gas emitted from an internal combustion engine. A deposition part and at least a pair of detection electrodes are formed on an end surface of the element part. Some of particles of PM is deposited on the deposition part. The pair of detection electrodes are arranged on the deposition part. The particulate matter detection sensor changes its output electrical signal according to variation of electrical properties between the pair of the detection electrodes due to deposition of PM on the deposition part. A concave collection part is formed on the deposition part. The concave collection part has a concaved shape when viewed from the edge surface of the element part.

A particulate matter detection apparatus includes a particulate matter quantity detection means, a temperature detection means that detects the temperature of exhaust gas, a control unit and a heating means. The particulate matter quantity detection means includes a particulate matter deposition portion that deposits thereon part of particulate matter contained in the exhaust gas emitted from an internal combustion engine and a pair of opposite electrodes arranged apart from each other on the particulate matter deposition portion. The control unit determines a deposition quantity of the particulate matter on the particulate matter deposition portion based on an electrical signal outputted by the particulate matter quantity detection means and receives information on the temperature of the exhaust gas detected by the temperature detection means. The control unit controls the heating means to heat the particulate matter deposition portion to 300&#xb0; C.-800&#xb0; C. during a cold start of the internal combustion engine.

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Kariya, Japan

Go Miyagawa