Nissan Motor Company Limited

Makoto Otake

Naoya Tsutsumoto

Junichi Kawashima

Terunori Kondou

Takao Inoue

Toshimasa Koga

Shouichirou Ueno

Munehiro Tabata

Masahiko Nakano

Jun-ichi Kawashima

Junichi Kawashiwa

A diesel engine () comprises an exhaust passage (), and a DPM filter () provided on the exhaust passage (), which traps diesel particulate matter (DPM) contained in the exhaust gas such that the diesel particulate matter accumulates therein. An engine controller () starts regeneration processing of the DPM filter () by raising the exhaust gas temperature when a regeneration timing of the DPM filter () is reached, sets a target exhaust gas temperature during regeneration processing to ensure that the temperature of the DPM filter () does not exceed an upper temperature limit of the DPM filter (), even when the temperature of the DPM filter () is raised due to the engine () entering an idling condition during the regeneration processing, and controls the exhaust gas temperature to the target exhaust gas temperature.

Diesel engine comprising DPM filter and DPM filter regeneration method

A regeneration control device which regenerates a filter () which traps particulate matter in the exhaust gas of an engine () is disclosed. The regeneration control device includes a first temperature sensor (), which detects one of an upstream temperature and a downstream temperature upstream and downstream of the filter () as a first temperature (Tin, Tout); a second temperature sensor (), which detects the other temperature as a second temperature (Tin, Tout); and a microcomputer. The microcomputer programmed to compute an estimated value (Tbede) for the second temperature based on the first temperature detected by the first temperature sensor (), compute an estimated bed temperature (Tbed) of the filter based on the second temperature detected by a second temperature sensor () and the estimated value (Tbede) for the second temperature, and perform engine control for increasing the temperature of the exhaust gas based on the estimated bed temperature (Tbed).

Filter regeneration control

A regeneration control device which regenerates a filter () by increasing an exhaust gas temperature to burn exhaust gas particulates trapped in the filter, is disclosed. The filter () traps particulate matter in exhaust gas from an engine (). The regeneration control device suppresses fuel cost-performance impairment due to filter regeneration. The regeneration control device has a load detection sensor () which detects an engine load and a microcomputer-based controller (). The controller is programmed to perform engine control to adjust the exhaust gas temperature for regeneration of the filter (), when a computed trapped amount is equal to or more than the first reference value (A) and less than the second reference value (B), and the detected load (Vsp) is equal to or more than a reference load (Vo); and perform engine control to adjust the exhaust gas temperature for regeneration of the filter () regardless of the detected load (Vsp), when the computed trapped amount is equal to or more than the second reference value (B).

Filter regeneration in engine exhaust gas purification device

A filter () which traps particulate matter contained in the exhaust gas of a diesel engine () for a vehicle is regenerated by fuel injection control. A controller () calculates a representative value of the operating condition of the diesel engine () during a latest predetermined time period, and determines the traveling condition of the vehicle on the basis of this representative value. When the representative value corresponds to a highway traveling condition, fuel injection control is performed in accordance with a pattern for burning all of the particulate matter trapped in the filter (). Under any other conditions, fuel injection control is performed in accordance with another pattern. Hence optimum filter regeneration can be performed depending on the traveling condition of the vehicle.

Regeneration control of diesel particulate filter

A filter differential pressure, which is the difference between the inlet pressure and the outlet pressure of a DPM filter (), is determined, and switching is performed in accordance with the regeneration condition of the DPM filter () between a first trapped DPM amount calculation process for estimating the trapped DPM amount after complete regeneration, in which all of the DPM trapped in the DPM filter () is burned, and a second trapped DPM amount calculation process for estimating the trapped DPM amount when a part of the DPM trapped in the DPM filter () has been burned away. The trapped DPM amount in the DPM filter () is estimated on the basis of the filter differential pressure using one of the first and second trapped DPM amount calculation processes.

Diesel engine comprising DPM filter and method of estimating amount of DPM trapped in DPM filter

A diesel particulate filter () which traps particulate matter contained in the exhaust gas of a diesel engine () comprises an oxidation catalyst (A) which exhibits a temperature-raising effect during regeneration of the filter (). A controller () calculates the amount of particulate matter trapped in the filter () at the start of regeneration as a first amount, and calculates the amount of particulate matter burned during regeneration of the filter () as a second amount (S, S, S). A deterioration factor d of the oxidation catalyst is calculated from the ratio of the second amount and first amount, and a target temperature for the next regeneration of the filter is determined on the basis of this deterioration factor d. Thus deterioration of the oxidation catalyst (A) is compensated for, and an optimum temperature environment for regenerating the filter () is realized.

An exhaust gas purifying system of a diesel engine comprises a PM filter installed in an exhaust passage line of the engine to collect particulate matter (PM) in the exhaust gas from the engine; a pressure difference sensor for detecting a pressure difference between upstream and downstream portions of the PM filter; a control unit which comprises a collected PM amount estimating section that estimates an amount of collected PM in the PM filter based on the pressure difference; and a reactivation timing judging section that, based on the estimated amount of the collected PM, judges a reactivation time when the reactivation of the PM filter is needed; and a reactivation carrying out system that, upon judgment of the reactivation time, carries out a predetermined operation to increases the temperature of the PM filter thereby to burn the collected PM. The control unit further comprises a dispersion condition judging section that judges a dispersion condition of the collected PM in the PM filter; and a correction section that corrects the estimated amount of the collected PM in accordance with the judged dispersion condition of the collected PM.

Exhaust gas purifying system of internal combustion engine

A map which defines a relationship of an exhaust gas pressure Pat the outlet of a filter () to a load Q and rotation speed Ne of an engine () is prepared, and an exhaust gas pressure Pat the inlet to the filter () is determined from a differential pressure &#x394;P between the front and rear of the filter and the outlet pressure Pobtained by referring to the map. The inlet pressure Pdetermined in this manner is used to determine an exhaust gas volumetric flow rate Q, and thus an accurate particulate accumulation SM, which is required to determine the need for regeneration of the filter (), can be calculated.

Engine exhaust gas purification device

An engine exhaust gas purification device is disclosed. The purification device has a filter () which traps particulate matter contained in the exhaust gas from an engine; a differential pressure detection sensor () which detects a differential pressure of the filter; a sensor () which detects an engine running state, and a microcomputer (). The microcomputer () is programmed to compute an estimated ash amount ASH_a of the filter based on the detected differential pressure; compute an oil consumption amount OC_total based on the detected engine running state; compute an ash density DENS_ASH from the oil consumption amount OC_total and estimated ash amount ASH_a, and compute an ash amount ASH of the filter based on the oil consumption amount OC_total and ash density DENS_ASH.

To regenerate a diesel particulate filter () which traps particulate matter contained in the exhaust gas of a diesel engine (), a controller () raises the temperature of the exhaust gas through fuel injection control of a fuel injector (), and thus burns the particulate matter trapped in the filter (). The controller () cumulatively calculates the time during which the temperature of the filter () exceeds a target temperature as an effective regeneration time. By estimating the amount of particulate matter remaining in the filter () on the basis of the effective regeneration time, the controller () estimates the amount of remaining particulate matter with a high degree of precision and without consuming energy, whereupon regeneration of the filter () through fuel injection control ends.

In regeneration apparatus and method for a particulate filter that collects a particulate in exhaust gas of an internal combustion engine, a timing at which an accumulated particulate is combusted to regenerate the particulate filter is determined and a control is performed for a combustion of the particulate, during the control for the combustion of the particulate, a temperature of the engine exhaust gas is raised to a first target temperature set at a temperature equal to or higher than a criterion temperature which provides a criterion of whether the particulate is combusted to regenerate the particulate filter when the engine falls in a first driving region, and the engine exhaust gas temperature is raised to a second target temperature set at a temperature lower than the criterion temperature when the engine falls in a second driving region different from the first driving region.

Regeneration apparatus and method for particulate filter applicable to engine exhaust gas purifying device

A diesel particulate filter () traps particulate matter contained in the exhaust gas of a diesel engine () for a vehicle. The filter () is regenerated by raising the exhaust gas temperature so that the trapped particulate matter burns. A controller () calculates a particulate matter combustion amount PMr during regeneration, and in accordance with increases in the combustion amount PMr, raises the oxygen concentration of the exhaust gas by operating an intake throttle () and/or a variable nozzle () of a turbocharger (). As a result, the filter () is held at an optimum temperature for regeneration regardless of the residual particulate matter amount, and hence the time required for regeneration can be shortened without damaging the heat resistance performance of the filter ().

This invention relates to regeneration of a filter () which traps particulate matter contained in the exhaust gas of a diesel engine () for a vehicle. A programmable controller () performs filter regeneration appropriately in accordance with the running pattern of the vehicle by calculating a first parameter indicating the frequency with which the diesel engine () performs an idling operation over a predetermined time period up to the present (S), calculating a second parameter indicating the temperature environment of the filter () over a predetermined time period up to the present (S), and determining whether or not the filter () can be regenerated completely on the basis of the first parameter and second parameter (S).

Regeneration of diesel particulate filter

A regeneration control device, which regenerates a filter () for trapping particulate matter in exhaust gas from an engine (), is disclosed. The filter () supports a catalyst which oxidizes unburnt components in the exhaust gas. The regeneration control device has a temperature sensor () which detects a filter inlet exhaust gas temperature (Tdpf_in_mea); and a microcomputer (). The microcomputer () is programmed to compute a filter outlet exhaust gas temperature (Tdpf_out_cal), not including temperature rise due to oxidation reaction of unburnt components based on the detected inlet exhaust gas temperature; compute the filter bed temperature (Tbed_cal) based on the detected inlet exhaust gas temperature and computed outlet exhaust gas temperature; compute a temperature rise (&#x394;Thc) due to oxidation reaction of unburnt components; correct the bed temperature based on the computed temperature rise (&#x394;Thc).

A regeneration device for a filter () which traps particulate matter in an exhaust gas of an engine () is disclosed. The regeneration device has a sensor () which detects an engine running point containing an engine load and a controller () storing a map which defines a low load region (A) relating to engine running points. The controller () determines whether or not the detected engine running point is in the low load region referring to the map, when the deposition amount of particulate matter is more than a first reference amount (PMn). Further, the controller () immediately start a first filter regeneration control by raising a temperature of the exhaust gas, when the detected engine running point is not in the low load region, and start a second filter regeneration control by raising the temperature of the exhaust gas after the deposition amount of particulate matter exceeds a second reference amount (PMe), when the detected engine running point is in the low load region.

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Yokohama, Japan

Makoto Otake