Nissan Motor Company Limited

Takeshi Ishino

Hiroyuki Itoyama

Hiroshi Iwano

Kensuke Osamura

Kenji Oota

Yasutaka Ishibashi

Yuuichi Hosaka

Issho Uehara

An exhaust emission control device includes a first detection unit for detecting a NOx adsorption amount and an oxygen storage amount of a three-way catalyst and a NOx purification catalyst during rich spike, a second detection unit for detecting the oxygen storage amount of the three-way catalyst and the NOx purification catalyst until the output of a second air-fuel sensor becomes lean after the rich spike, and a deterioration determination unit for determining deterioration of the NOx purification catalyst based on a detected value of the first detection unit and that of the second detection unit.

Exhaust emission control device for internal combustion engine and NOx purification catalyst deterioration determination method

A basic target excess air factor tLAMBDA0 and a target fresh air intake amount tQac are set base upon the operation condition of an engine ( ). A target excess air factor tLAMBDA is calculated by multiplying the ratio of a real fresh air intake amount rQac as detected by a sensor ( ) and the target fresh air intake amount tQac by the basic target excess air factor tLAMBDA0. A fuel injector ( ) is controlled so that the amount of fuel injected thereby converges to a target fuel injection amount tQf which corresponds to the target excess air factor tLAMBDA. It is possible to prevent variation of the output torque of the engine ( ) accompanying a rich spike by this control, even if the basic target excess air factor tLAMBDA0 varies abruptly, since the fuel injection amount varies in correspondence to the variation of the real fresh air intake amount rQac.

Excess air factor control device for internal combustion engine

A method for controlling an engine comprises establishing a torque correction coefficient (KA) to compensate for reducing effect of available engine torque in operating range of different excess air ratios (&lgr;) that are lower than a predetermined value (unity&equals;1). An initial base desired in-cylinder air mass (tQacb) is determined based on a requested engine torque (tTe). A desired excess air ratio (t&lgr;) is determined. The initial base desired in-cylinder air mass (tQacb) is adjusted with at least the desired excess air ratio (t&lgr;) and the correction coefficient (KA) to generate a desired in-cylinder air mass (tQac). A desired injected fuel mass (tQf) is controlled based on the desired in-cylinder air mass (tQac) to deliver the requested engine torque (tTe) with the desired excess air ratio (t&lgr;) held accomplished.

Method and system for controlling an engine with enhanced torque control

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Futtsu, Japan

Takeshi Ishino