Mazda Motor Corporation

Motoshi Kataoka

Daisuke Shimo

Tomoaki Saito

Masahiko Fujimoto

Eiji Nakai

Masanobu Kanno

Kenji Tanimura

Daisuke Fukuda

Hiroshi Hayashibara

Yasuyuki Terazawa

Hideharu Iwakuni

Naotoshi Shirahashi

Sangkyu Kim

Kota Maekawa

Takashi Takemoto

Yoshie Kakuda

Akihiro Kobayashi

Takahiro Yamamoto

Takeru Matsuo

Kazuhiro Furukawa

An exhaust gas recirculation control device of an engine is provided. The device includes: an exhaust turbocharger having a turbine disposed in an exhaust passage and a compressor disposed in an intake passage; a low-pressure EGR passage connecting a part of the exhaust passage downstream of the turbine to a part of the intake passage upstream of the compressor; a low-pressure EGR valve disposed in the low-pressure EGR passage and for changing a cross-sectional area of the low-pressure EGR passage; an exhaust shutter valve disposed downstream of the connected part of the exhaust passage to the low-pressure EGR passage, and for changing a cross-sectional area of the exhaust passage; a valve control device for controlling openings of the low-pressure EGR valve and the exhaust shutter valve; and a gear range detector for detecting a gear range of a transmission of a vehicle in which the engine is installed.

Exhaust gas recirculation control system of engine

An exhaust gas recirculation control device of an engine is provided. The device includes: an exhaust turbocharger having a turbine disposed in an exhaust passage and a compressor disposed in an intake passage; an intercooler disposed in the intake passage downstream of the compressor; a low-pressure EGR passage connecting the exhaust passage downstream of the turbine to the intake passage upstream of the compressor; a low-pressure EGR valve disposed in the low-pressure EGR passage and for changing a cross-sectional area thereof; a high-pressure EGR passage connecting the exhaust passage upstream of the turbine to the intake passage downstream of the intercooler; a high-pressure EGR valve disposed in the high-pressure EGR passage and for changing a cross-sectional area thereof; a valve control device for controlling openings of the low-pressure and high-pressure EGR valves; and a gear range detector for detecting a gear range of a transmission.

Exhaust gas recirculation system of engine

A wall shape of a cavity consists of an inward protruding portion located at the periphery of an opening, a center portion projecting toward a fuel injector, and a peripheral portion connecting the inward protruding portion and the center portion. The fuel injector and the cavity are configured so that fuel injected from fuel injector directs to the proximity of the border between the inward protruding portion and the peripheral portion. The peripheral portion consists of a first portion located farthermost from the fuel injector, a second portion located between the inward protruding portion and the first portion, and a third portion located between the first portion and the center portion. The radii of arcs of the peripheral portion decrease from the second portion to the first portion and increase from the first portion to the third portion.

Diesel engine

A fuel injection nozzle for a diesel engine. The fuel injection nozzle may include a plurality of injection hole groups, each having two injection holes respectively. A distance between the two injection holes, an angle between longitudinal axes of the two injection holes and an angle between horizontal axes of said two injection holes of each injection hole group are each set such that fuel sprays injected from said two injection holes will form a single fuel spray cloud after the fuel sprays collide with a side wall of a combustion chamber formed in a top surface of a piston of the engine, and such that the distance between collision points of the fuel sprays will be in a predetermined range in which a penetration force of said fuel spray cloud along a longitudinal direction of said combustion chamber received after collision with said wall of said combustion chamber is at or near a predetermined maximum value.

Diesel engine and fuel injection nozzle therefor

An engine exhaust gas purifier includes: an injection controller allowing a fuel injection valve to inject fuel near the top dead center on each compression stroke; an EGR amount controller for controlling the amount of exhaust gas recirculated into a combustion chamber; an excess air ratio controller for controlling the excess air ratio so that the local equivalence ratio in a late combustion stage is lower than the equivalence ratio at which soot is produced; and an intake air temperature controller for controlling the temperature of intake air after being mixed with exhaust gas. The intake air temperature controller controls the temperature of intake air within a temperature range lower than an upper temperature limit below which a predetermined ignition delay time can be secured and higher than a lower temperature limit above which the production of HC and CO can be avoided.

Engine exhaust gas purifier

To suppress deposition of fuel injected at an early timing on a wall surface for preventing the degradation in fuel efficiency and increase in the amount of harmful components in an exhaust gas, in a direct-injection diesel engine which controls the injector to cause a combustion configuration dominated by the compressive ignition of the premixture while the engine is in the premixed combustion region defined on a low load side. When fuel is injected at an early timing to form the premixture, at least one of the pulse width to be inputted into the injector and the fuel pressure is or are adjusted according to the change in the injection timing, and corrected according to the intake air temperature or the intake pressure. If an allowable pulse width is insufficient to inject fuel in the amount corresponding to a target torque, fuel is injected in a divided manner.

Combustion control apparatus for a diesel engine

To optimize an ignition timing of premixture for improving fuel efficiency regardless of significant change in an EGR ratio or a fluctuation in temperature of recirculated exhaust gas and temperature in a combustion chamber, there is provided a control apparatus for a diesel engine which controls an injector extending into the combustion chamber to execute a main-injection for injecting fuel and increasing the EGR ratio, so as to attain the premixed compressive ignition combustion while the engine is in the premixed combustion region on the low load side. Just before or after a cool flame reaction occurs in the mixture formed by the main-injection, an auxiliary-injection is executed so that the latent heat of vaporization of the fuel decreases the temperature of the mixture to delay the ignition to a timing near TDC. The auxiliary-injection amount is adjusted according to the estimated value of EGR ratio or the change in the crank angular velocity to optimize the ignition timing of the mixture.

Combustion control apparatus for an engine

In a combustion control apparatus of a direct-injection diesel engine, in which a fuel is injected at an early timing with an EGR ratio more than a first predetermined value at pre-mixed combustion area (H) where an engine load is relatively low so as to provide a pre-mixed combustion mode, while a diesel combustion mode is provided with the EGR ratio less than a second predetermined value at diffusion combustion area (D), when the operation of the engine transfers from one of the pre-mixed combustion area (H) and the diffusion combustion area (D) to the other thereof, an opening of the an EGR valve is changed and thereby a fuel injection mode is changed after an actual EGR ratio: EGR becomes a predetermined value: EGR1. When the EGR ratio: EGR is within a certain range (SB &rarr;SB &rarr;SB ), a follow-up injection (latter-injection) is executed (SB , SB ) so that combustion thereby may begin at the timing when the main-combustion beginning at around TDC completes mostly. The latter-injection can make smoke produced by the main-injection burn again effectively. As a result, smoke concentration in the exhaust gas can be reduced greatly, and a transient deterioration of the exhaust gas condition at the transition between the operating areas (H), (D) and the like can be avoided.

Combustion control apparatus of diesel engine

An exhaust gas purification system having a catalyst for removing nitrogen oxides from exhaust gas causes the temperature range of activation of the catalyst to shift toward the higher temperature side when the degree of oxidation of the catalyst becomes pronounced.

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Hiroshima, Japan

Motoshi Kataoka