Abstract: An intake air pressure P1 and a target control value S1 under the condition that the internal combustion engine is in a steady operating state and the condition that the turbocharger has its supercharging efficiency set to a ratio according to the engine operating state are estimated based on engine parameters, and an intake air pressure P2 and a target control value S2 under the condition that the internal combustion engine is in the steady operating state and the condition without supercharging by the turbocharger are estimated based on the engine parameters. A target control value S0 associated with an actual intake air pressure P0 under the condition that the internal combustion engine is in a transient operating state is calculated by performing interpolation on the target control values S1, S2 based on a relation between the intake air pressures P1, P2 and the actual intake air pressure P0.

Abstract: An intake air pressure P1 and a target control value S1 under the condition that the internal combustion engine is in a steady operating state and the condition that the turbocharger has its supercharging efficiency set to a ratio according to the engine operating state are estimated based on engine parameters, and an intake air pressure P2 and a target control value S2 under the condition that the internal combustion engine is in the steady operating state and the condition without supercharging by the turbocharger are estimated based on the engine parameters. A target control value S0 associated with an actual intake air pressure P0 under the condition that the internal combustion engine is in a transient operating state is calculated by performing interpolation on the target control values S1, S2 based on a relation between the intake air pressures P1, P2 and the actual intake air pressure P0.

Abstract: According to the present invention, there is provided an exhaust gas purification device for an engine having an exhaust passage, the device comprising a catalyst arranged in the exhaust passage and having an upstream end and a downstream end, a purification ratio of exhaust gas by the catalyst becoming more than a predetermined ratio when a temperature of the catalyst is within a predetermined temperature range, cooling means for cooling the upstream end of the catalyst, heating means for heating the downstream end of the catalyst, and control means for controlling the cooling means and the heating means to maintain the temperature of a portion of the catalyst, which portion is positioned between the upstream end and the downstream end, in the predetermined temperature range.

Abstract: According to the present invention, there is provided an exhaust gas purification device for an engine having an exhaust passage, the device comprising a catalyst arranged in the exhaust passage and having an upstream end and a downstream end, a purification ratio of exhaust gas by the catalyst becoming more than a predetermined ratio when a temperature of the catalyst is within a predetermined temperature range, cooling means for cooling the upstream end of the catalyst, heating means for heating the downstream end of the catalyst, and control means for controlling the cooling means and the heating means to maintain the temperature of a portion of the catalyst, which portion is positioned between the upstream end and the downstream end, in the predetermined temperature range.

Abstract: In a fuel injection control system, a throttle valve is provided on the intake air passage of a diesel engine and an EGR control valve is provided for recycling a part of the engine exhaust gas to the intake air system of the engine. An engine control unit (ECU) controls the intake air amount of the engine to a value corresponding to the engine operating condition by adjusting the throttle valve and the EGR control valve. Further, the ECU detects the actual intake air amount by an airflow meter disposed at the inlet of the intake air passage and determines the maximum fuel injection amount based on the engine speed and the actual intake air amount. The maximum fuel injection amount is the maximum amount of the fuel which does not generate the exhaust smoke.

Abstract: According to the invention, there is provided an exhaust gas purification device for purifying an exhaust gas discharged from an engine having cylinders including first and second cylinders. An exhaust stroke in the first cylinder is carried out next to an exhaust stroke in the second cylinder. The exhaust gas purification device comprises exhaust branch passages which are connected to the cylinders, respectively. The exhaust branch passages include first and second exhaust branch passages which are connected to the first and second cylinders, respectively. The exhaust gas purification device comprises a common exhaust passage connected to the exhaust branch passages, a catalyst positioned in the common exhaust passage for purifying an exhaust gas, and an exhaust gas recirculation passage connected to the first exhaust branch passage. The exhaust gas recirculation passage introduces the exhaust gas from the first exhaust branch passage into an intake passage which is connected to the cylinders.

Abstract: According to the present invention, there is provided a fuel injecting device for injecting fuel into a cylinder of an engine. A fuel injector injects a main fuel charge into the cylinder at a predetermined first timing, and the fuel injector injects additional fuel into the cylinder at a predetermined second timing which is different from the predetermined first timing. It is judged if an amount of fuel adhering to an inner wall of the cylinder is larger than a predetermined fuel amount when the fuel injector injects the additional fuel. The fuel injector inject the additional fuel such that an amount of fuel adhering to the inner wall of the cylinder becomes smaller than the predetermined fuel amount when it is judged that an amount of fuel adhering to the inner wall of the cylinder is larger than the predetermined fuel amount.

Abstract: An exhaust gas purification device, for an engine having an exhaust passage, said device comprising a catalyst arranged in the exhaust passage for purifying NO.sub.x with a reducing agent. A purification ratio of the NO.sub.x by said catalyst becomes more than a predetermined ratio when a temperature of said catalyst is within a predetermined temperature range. A predetermined amount of a reducing agent is fed to said catalyst. An amount of the reducing agent to be fed is increased with respect to the predetermined amount when a temperature of an upstream end of the catalyst is lower than a lowest value of the predetermined temperature range and a temperature of a downstream end of the catalyst is higher than the lowest value.

Abstract: An exhaust gas purifying device, for an engine performing a lean operation and having an EGR system capable of controlling an EGR ratio, comprises a NO.sub.X catalyst arranged in the exhaust passage capable of selectively reducing NO.sub.X in the inflowing exhaust gas, in the oxidizing atmosphere including a reducing agent, and a reducing agent injector arranged in the exhaust passage of the engine for secondarily supplying a reducing agent to the exhaust passage upstream of the NO.sub.X catalyst. The EGR system has an EGR passage connecting the exhaust passage and the intake passage of the engine, an EGR control valve arranged in the EGR passage, and an intake air control valve arranged in the intake passage upstream of an inlet of the EGR passage. The openings of the EGR control valve and the intake air control valve are controlled to control the temperature of the exhaust gas to make the temperature of the NO.sub.X catalyst within the optimum temperature range or equal to the optimum temperature.

Abstract: An exhaust emission gas purification apparatus for an internal combustion engine is disclosed, in which a proper purification rate can be maintained even at a transient time by suppressing an excessive temperature increase of a lean NO.sub.x catalyst. In order to improve the purification efficiency of a lean NO.sub.x catalyst 307, diesel fuel constituting a hydrocarbon material capable of reducing the NO.sub.x is supplied by way of a diesel fuel injection hole 311. A basic amount of diesel fuel to be supplied is determined on the basis of a space velocity SV providing a quantity of state representing the operating conditions of the catalyst calculated from the intake air amount detected by an air flowmeter 302 and the catalyst temperature detected by an outlet exhaust gas temperature sensor 322. The basis amount of diesel fuel to be supplied is corrected based on the difference between the catalyst temperature and the inlet exhaust gas temperature detected by the inlet exhaust gas temperature sensor 321.

Abstract: A fuel injection control device for a direct injection type engine having an exhaust passage and a NO.sub.x catalyst arranged therein to purify NO.sub.x in exhaust gas discharged from the engine comprises fuel injectors for injecting fuel into a cylinder. The injecting operation of the fuel injectors is controlled to carry out a main fuel injection at the latest at the beginning of a power stroke of the engine. The injecting operation of the fuel injectors is controlled to carry out a sub fuel injection at one of a power stroke and an exhaust stroke of the engine after the main fuel injection is completed to increase an amount of hydrocarbon in the exhaust gas. The injecting operation of the fuel injectors is controlled to carry out an additional sub fuel injection after the main fuel injection is completed and before the sub fuel injection is carried out.