Isuzu Motors Limited

Yoshinobu Watanabe

Tatsuo Mashiko

Takashi Haseyama

Takao Onodera

Kenji Hagio

Takuro Iwashita

Naofumi Ochi

Shinji Gotou

In forced regeneration control of an exhaust gas purification device, data for control such as the number of meshes of a data map and the number of data maps for forced regeneration control is reduced and occurrence of torque shock is avoided by smoothly changing a fuel pressure. In the forced regeneration control of the exhaust gas purification device, when an operation state of an internal combustion engine is in a high-load operation state, normal injection control by stopping multi injection is carried out and according to a rotation speed and a load of the internal combustion engine, a region for control is divided into a multi-injection control region, a transition region, and a normal injection control region, and in the transition region, data for fuel pressure control obtained by interpolation of data for fuel pressure control on the multi-injection control region side and data for fuel pressure control on the normal injection control region side is used.

Control method of exhaust gas purification system and exhaust gas purification system

At regeneration control while a vehicle mounting an internal combustion engine () is parked, both an exhaust throttle valve () and an exhaust brake valve () are used and if a catalyst temperature index temperature (Tg) is lower than a predetermined first determining temperature (Tc), first exhaust gas temperature rise control is conducted that the exhaust brake valve () is set to a fully closed side and multiple injection is carried out in in-cylinder fuel injection control, while if a catalyst temperature index temperature (Tg) is equal to the predetermined first determining temperature (Tc) or above, second exhaust gas temperature rise control is conducted that the exhaust brake valve () is set to an open side, the exhaust throttle valve () is set to the fully closed side, and post injection is carried out in the in-cylinder fuel injection control. By this arrangement, while temperature rise efficiency of an exhaust gas flowing into a DPF () is enhanced, forced regeneration is carried out efficiently in a short time with avoiding overheat or abnormal combustion at the regeneration control of the DPF () while the vehicle is parked.

In regeneration control, when the catalyst temperature index temperature (Tg) using the temperature of the oxidation catalyst () as an index is below a predetermined first determination temperature (Tc), the engine speed of idling is brought to a predetermined first target engine speed (Nei) which is higher than the engine speed of idling (Nei) in the ordinary operation, and, further, multi-injection is carried out. On the other hand, when the catalyst temperature index temperature (Tg) is the predetermined first determination temperature (Tc) or above, the engine speed of idling is brought to a predetermined second target engine speed (Nei), which is lower than the predetermined first target engine speed (Nei) and is higher than the engine speed of idling (Nei) in ordinary operation, and, further, post injection is carried out, followed by raising of the temperature of an exhaust gas flown into a DPF apparatus () to a predetermined second determination temperature (Tc). According to the above constitution, in the regeneration control of the DPF apparatus () in an internal combustion engine (), the regeneration can be forcibly carried out with high efficiency while enhancing the temperature rise efficiency of the exhaust gas, and, at the same time, excessive rise in the exhaust temperature, a deterioration in fuel consumption, and the occurrence of noise are suppressed.

Method for controlling exhaust gas purification system and exhaust gas purification system

In an exhaust gas purification system () for conducting control of raising temperature of a DPF () by supplying an unburned fuel to an upstream side of an oxidation catalyst to oxidize it, a minimum value (Qumin) of a first upper limit value (Qu) acquired by subtracting a fuel injection amount (Qe) for in-cylinder combustion from a first combustible fuel amount (Qa) limited by an air/fuel ratio, a second upper limit value (Qu) acquired by subtracting the fuel injection amount (Qe) for in-cylinder combustion from a second combustible fuel amount (Qa) limited by an atmospheric pressure, and a third upper limit value (Qu), which is a third combustible fuel amount (Qa) which can be oxidized by the oxidation catalyst limited by a catalyst temperature index temperature (Tg, Tg) and an engine speed (Ne) is set as an upper limit value (Qu) for the unburned fuel supply amount (Qp). By this arrangement, at forced regeneration of the DPF (), the unburned fuel supplied into an exhaust gas is surely oxidized and generation of white smoke is prevented regardless of an operation state of an internal combustion engine ().

Exhaust gas purification method and exhaust gas purification system

An exhaust gas purification system including an exhaust gas purification device having an oxidation catalyst device including an oxidation catalyst and a diesel particulate filter ('DPF') arranged in order from an upstream side, or a DPF carrying an oxidation catalyst in an exhaust passage of an internal combustion engine. At regeneration of the DPF, when a catalyst temperature index temperature (Tg), indicating a temperature of the oxidation catalyst, becomes equal to a predetermined determining temperature (Tc) or above, a temperature of the DPF is raised by supplying an unburned fuel to the upstream side of the oxidation catalyst to thereby oxidize the unburned fuel by the oxidation catalyst. The predetermined determining temperature (Tc) is changed according to an engine speed Ne of the internal combustion engine. By so oxidizing the unburned fuel supplied into an exhaust gas by the oxidation catalyst, outflow of white smoke is prevented regardless of an operation state of the internal combustion engine.

A fuel injection control device that prevents a misfire is provided. The fuel injection control device comprises: target injection amount determination meansfor determining a target injection amount of each fuel injection, so that the amount of fuel to be supplied to a cylinder in one combustion cycle is supplied in a plurality of fuel injections; and fuel injection correction amount determination meansfor determining a fuel correction amount of one combustion cycle, wherein the fuel injection correction amount determination meansdistributes the correction amount among each fuel injection in accordance with the ratio of a target injection amount of each fuel injection in the cylinder.

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Fujisawa, Japan

Yoshinobu Watanabe