Isuzu Motors Limited

Transtron Inc.

Hidekazu Fujie

Tadashi Uchiyama

Satoshi Hanawa

Naoto Murasawa

Teruo Nakada

Yoshiaki Ikai

Mitsuhiro Aso

Takuma Degawa

Kazuo Oosumi

In order to adequately suppress both an increase in NOx emission amount and deterioration of fuel consumption rate, the present invention provides a fuel injection control information generation device equipped with: a test point information storage unit for holding test point information including a plurality of test points constituted by sets of engine speed, fuel injection amount, and oxygen concentration; and a control information generation unit for generating, for each test point included in the test point information, fuel injection control information in which the engine speed, fuel injection amount, and oxygen concentration of the test point are associated with an optimum fuel injection timing at which an index pertaining to the total of a fuel consumption rate and an NOx emission amount in the test point becomes the smallest.

Fuel injection control information generation device and control device

An exhaust purification system includes: a diesel oxidation catalyst (DOC) provided on an exhaust path of an engine; an upstream diesel particulate filter (DPF) and a downstream DPF that are provided on the exhaust path at positions downstream of the DOC to collect particulate matter contained in exhaust gas; electrodes that detect a capacitance of the upstream DPF; a particulate matter accumulation estimating unit that estimates at least an amount of particulate matter accumulated in the downstream DPF on the basis of the capacitance received from the electrodes; and a forced regeneration control unit that injects fuels into the DOC and performs forced regeneration that burns and removes at least the particulate matter accumulated in the downstream DPF when the estimated amount of particulate matter from the particulate matter accumulation estimating unit surpasses a predetermined amount.

Exhaust purification system

A diagnosis device includes: a diesel particulate filter (DPF) collecting particulate matter (PM) in exhaust gas; a resistive type PM sensor provided downstream of the DPF, detecting an amount of PM from current flowing through PM deposited between electrodes. An actual regeneration interval calculator calculating an actual interval from completion of regeneration of the sensor to a start of the next regeneration; a PM slippage amount calculator estimating an amount of PM slippage in exhaust gas that slips through the DPF, assuming the DPF is normal; an estimated regeneration interval calculator calculating, on the basis of the PM slippage amount, an estimated interval from completion of the regeneration of the sensor to the start of the next regeneration; and a DPF failure-normal determination device determining whether the DPF has failed or is normal by comparing the actual interval to the estimated interval.

Diagnosis device

A diagnostic device includes: a diesel oxidation catalyst (DOC) for oxidizing hydrocarbon (HC) and nitrogen monoxide in an exhaust gas; a selective catalytic reduction (SCR) catalyst for reducing and purifying NOx contained in the exhaust gas; a NOx purification rate calculation unit which calculates, based on NOx values at upstream and downstream sides of the SCR catalyst, a low temperature NOx purification rate and a high temperature NOx purification rate; a HC heat generation rate calculation unit which calculates an HC purification rate based on at least the difference between the exhaust gas heat quantities at upstream and downstream sides of the DOC; and a deterioration determination unit which determines the deterioration in the NOproducing capability of the DOC based on the calculated low temperature NOx purification rate, the calculated high temperature NOx purification rate, and the calculated HC purification rate.

Diagnostic device for an oxidation catalyst

A diagnosis device diagnoses a cooler adapted to cool a fluid flowing through intake and exhaust systems of an engine, and includes: a downstream temperature sensor for detecting a fluid temperature downstream of the cooler; a fluid temperature calculation unit for calculating a fluid temperature upstream of the cooler based on a fluid state quantity; a sensor output value calculation unit for assuming an upstream temperature sensor configured to detect a fluid temperature upstream of the cooler, reflecting a sensor response delay in the calculated fluid temperature, and calculating an estimated sensor output value of the upstream temperature sensor; and a cooler diagnosis unit for diagnosing the cooling efficiency of the cooler based on an actual sensor input value entered from the downstream temperature sensor and the calculated estimated sensor output value.

An exhaust purification system includes: a diesel oxidation catalyst (DOC) provided on an exhaust passage of an engine; a diesel particulate filter (DPF) provided on the exhaust passage at a position downstream of the DOC to collect particulate matter contained in exhaust gas; electrodes that detect a capacitance of the DOC; a particulate matter accumulation estimating unit that estimates an amount of particulate matter accumulated in the DPF on the basis of the detected capacitance; and a forced regeneration control unit that injects fuel into the DOC and performs forced regeneration that burns and removes at least the particulate matter accumulated in the DPF when the estimated accumulated particulate matter amount surpasses a predetermined amount.

A diagnostic device includes: a DOC for oxidizing hydrocarbon (HC) contained in an exhaust gas; a first sensor for detecting an exhaust gas temperature at a DOC inlet; a second sensor for detecting an exhaust gas temperature at a DOC outlet; a third sensor for detecting ambient temperature; an HC heat generation rate calculation unit which calculates, based on detection values of the first and second sensors, a difference in an exhaust gas heat quantity between upstream and downstream sides of the DOC, calculates, based on the detection values of the three sensors, a heat loss quantity released to outside air from the DOC, and adds the heat loss quantity and the exhaust gas heat quantity difference to calculate a heat generation quantity of HC in the DOC; and a DOC deterioration determination unit which determines, based on the calculated HC heat generation quantity, deterioration of the DOC.

Diagnostic device

A diagnostic device for an exhaust gas purification system that has a diesel oxidation catalyst (DOC), a diesel particulate filter, and an exhaust pipe injection device. The device includes a sensor for detecting a temperature of the DOC, a first calculation unit for converting an integration time of the detected temperature between regeneration intervals into a thermal history time with respect to a predetermined set temperature, and calculating a degree of degradation of the DOC based on this thermal history time, a second calculation unit for calculating a quantity of heat generated in the DOC based on the detected temperature during a forced regeneration execution period, and calculating another degree of degradation of the DOC based on the quantity of heat generated; and a diagnosis unit for diagnosing a degradation state of the DOC based on the degrees of degradation entered from the first and second calculation units.

An exhaust purification system includes a selective catalytic reduction (SCR) catalyst disposed at an exhaust system of an engine for using ammonia that is generated from urea water as a reducing agent to reduce NOx contained in exhaust gas, a device that injects urea water to the SCR catalyst, an inlet-side electrode that detects capacitance within the SCR catalyst at least from a vicinity of an inlet of the SCR catalyst to a vicinity of an intermediate section in an exhaust gas flowing direction, an outlet-side electrode that detects the capacitance within the SCR catalyst at least from the vicinity of the intermediate section to an outlet of the SCR catalyst in the exhaust gas flowing direction, and a calculation unit that calculates an ammonia adsorption amount within the SCR catalyst on a basis of the capacitances detected from the inlet-side and the outlet-side electrodes.

The present invention provides a DPF failure detection method and a DPF failure detection device, which can be realized with a simple configuration and detect a failure at low cost. The theoretical deposited amount of PM on a DPFis calculated from the operating state of an internal combustion engine. The actual deposited amount of the PM on the DPFis measured based on the electrical capacitance of an electrical capacitance type PM sensor. When the divergence of the actual deposited amount from the theoretical deposited amount exceeds an allowable limit, it is determined that the DPFhas a failure.

Growing community of inventors

Yamato, Japan

Hidekazu Fujie