Mazda Motor Corporation

Mazda Motor Corporat Ion

Takeshi Matsubara

Naotoshi Shirahashi

Tsunehiro Mori

Yasunori Uesugi

Takahiro Yamamoto

Takeshi Inazumi

Kiyoaki Iwata

Sangkyu Kim

Kenko Ujihara

Hiroaki Shiiba

Tunehiro Mori

Tetsuya Fujioka

Keisuke Kawahara

Takeru Matsuo

Kiyonori Nagato

In a compression-ignition engine having a two-stage cavity, the distribution ratio between fuel for an upper cavity and fuel for a lower cavity is maintained even when the operational state of the engine changes. A piston of the engine includes a lower cavity, an upper cavity, and a lip portion between the lower cavity and the upper cavity. A controller causes a main injection and at least one pilot injection to be executed when an engine operates in a first state and a second state in which the speed is higher than the speed in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller maintains an injection amount of the main injection and increases an injection amount of the pilot injection(s) when the engine operates in the second state as compared to when the engine operates in the first state.

Engine system

In a compression-ignition engine having a two-stage cavity, the distribution ratio between fuel for an upper cavity and fuel for a lower cavity is maintained even when the operational state of the engine changes. A piston of the compression-ignition engine includes a lower cavity, an upper cavity, and a lip portion between the lower cavity and the upper cavity. A controller causes a main injection and at least one pilot injection to be executed when the engine operates in a first state and a second state in which the speed is higher than the speed in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller increases an injection amount per pilot injection when the engine operates in the second state than when the engine operates in the first state.

A diesel engine system is provided, which includes a piston having a cavity dented downwardly in a crown surface thereof and having a bottom part, a peripheral part dented so as to be convex radially outward, and a lip part formed above the peripheral part and protruding so as to be convex radially inward in a cross-sectional view. An injection controller causes an injector to perform, during operation in a given operating range, a main injection in which injected fuel is directed to the lip part, and an after-injection in which a smaller amount of the fuel than the main injection is injected at a given timing later than the main injection in an expansion stroke. An injection interval period from an end of the main injection to a start of the after-injection is shorter as a temperature parameter related to a progress of a warmup of engine increases.

Diesel engine system

A diesel engine system has a piston in which a cavity is formed in a crown surface. The cavity has a bottom part, a peripheral part dented so as to be convex radially outward in a cross-sectional view, and a lip part formed above the peripheral part and protruding so as to be convex radially inward in the cross-sectional view. An injection controller causes an injector to perform, during operation in a given operating range, a main injection in which injected fuel is directed to the lip part, and an after-injection in which a smaller amount of fuel than the main injection is injected at a given period later than the main injection in an expansion stroke. An injection interval period that is a period of time from an end of the main injection to a start of the after-injection is shorter as an injection pressure of fuel increases.

In a compression-ignition engine having a two-stage cavity, the distribution ratio between fuel for an upper cavity and fuel for a lower cavity is maintained even when the operational state of the engine changes. A piston of the compression-ignition engine includes a lower cavity, an upper cavity, and a lip portion between the lower cavity and the upper cavity. A controller causes a main injection and at least one pilot injection to be executed when the engine operates in a first state and a second state in which the load is higher than the load in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller causes a ratio of injection amount per pilot injection to the total injection amount to be higher when the engine operates in the second state than when the engine operates in the first state.

A fuel injection control device causes an injector to execute main injection or pilot injection toward a joint portion, and low penetration injection to inject fuel at timing earlier than the pilot injection in a PILOT region or at timing later than the main injection in an AFTER region. The fuel injection control device causes the low penetration injection to be executed to inject the fuel only in a radial central region of a combustion chamber.

Fuel injection control system and fuel injection control method for diesel engine

In a compression-ignition engine having a two-stage cavity, the distribution ratio between fuel for an upper cavity and fuel for a lower cavity is maintained even when the operational state of the engine changes. A piston of the engine includes a lower cavity, an upper cavity, and a lip portion therebetween. A controller causes a main injection and at least one pilot injection to be executed when the engine operates in a first state and a second state in which the load is lower than the load in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller sets the timing of the pilot injection(s) so that the distribution ratio of the fuel spray of the pilot injection(s) for the lower cavity is higher when the engine operates in the first state than when in the second state.

A fuel injection control causes a fuel injection valve to execute at least: a main injection to inject fuel at timing when a piston is positioned near a compression top dead center; a pilot injection to inject the fuel at timing earlier than the main injection; and a low penetration injection to inject the fuel at timing earlier than the pilot injection or timing later than the main injection. The fuel injection control device includes: a first injection control module that executes at least one of the main injection or the pilot injection at timing to inject the fuel toward a joint portion of a cavity; and a second injection control module that executes the low penetration injection to inject the fuel only into a radial central region of a combustion chamber.

In a compression-ignition engine having a two-stage cavity, the distribution ratio between fuel for an upper cavity and fuel for a lower cavity is maintained even when the operational state of the engine changes. A piston of the engine includes a lower cavity, an upper cavity, and a lip portion between the lower cavity and the upper cavity. A controller causes a main injection and at least one pilot injection to be executed when the engine operates in a first state and a second state in which the load is lower than the load in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller outputs a control signal to a fuel injection valve so that a distribution ratio for the upper cavity is higher when the engine operates in the second state than when in the first state.

Provided is an engine control device capable of, when performing control of an in-cylinder oxygen concentration according to engine operation state, controlling an engine to accurately realize vehicle behavior intended by a driver, while suppressing generation of knock noises due to abnormal combustion. The engine control device comprises: a basic target torque-determining part () configured to determine a basic target torque based on a driving state of a vehicle including manipulation of an accelerator pedal; a torque reduction amount-determining part () configured to determine a torque reduction amount based on a driving state of the vehicle other than the manipulation of the accelerator pedal; a final target torque-determining part () configured to determine a final target torque based on the basic target torque and the torque reduction amount; and an engine control part () configured, based on a fuel injection parameter preliminarily set correspondingly to an operation state of an engine, to control a fuel injector to enable the engine to output the final target torque, and, when the final target torque changes correspondingly to a change in the torque reduction amount, to correct the fuel injection parameter.

Engine control device

A method of controlling a fuel injection of a diesel engine for performing a plurality of fuel injections to cause a plurality of combustions inside a cylinder in one combustion cycle, is provided, which includes acquiring an oxygen concentration inside the cylinder, performing, on compression stroke, the plurality of fuel injections at substantially even injection intervals while increasing the injection intervals as the oxygen concentration decreases, and performing, after the plurality of fuel injections, another fuel injection including a larger injection amount than in the plurality of fuel injections, near a top dead center of the compression stroke.

Method and device for controlling fuel injection of diesel engine

A method of controlling a fuel injection of a diesel engine for performing a plurality of fuel injections to cause a plurality of combustions inside a cylinder in one combustion cycle, is provided, which includes performing, on compression stroke, the plurality of fuel injections at substantially constant injection intervals while increasing an injection amount as an in-cylinder oxygen concentration decreases, and performing, after the plurality of fuel injections, another fuel injection including a larger injection amount than in the plurality of fuel injections near a top dead center of the compression stroke.

Provided is a control device for an engine comprising an engine whose combustion mode is switchable according to an engine operation state, wherein the control device is capable of controlling the engine while suppressing generation of knock noise due to abnormal combustion. The control device comprises: a basic target torque-determining part () configured to determine a basic target torque based on a vehicle driving state including manipulation of an accelerator pedal; a torque reduction amount-determining part () configured to determine a torque reduction amount based on a vehicle driving state other than the manipulation of the accelerator pedal; a final target torque-determining part () configured to determine a final target torque based on the basic target torque and the torque reduction amount; and an engine control part () configured to set the combustion mode to a premixed combustion mode or a diffusion combustion mode according to the engine operation state. The engine control part is configured, when the engine operation state changes from a diffusion combustion region to a premixed combustion region, due to a change in the final target torque corresponding to a change in the torque reduction amount, to maintain the combustion mode in the diffusion combustion mode.

The compression self-ignition engine fuel injection control device is configured to, during one combustion stroke, perform multiple fuel injections to induce multiple combustions in a cylinder. The fuel injection control device comprises a PCM () configured to set an interval between temporally-adjacent two of the multiple fuel injections, so as to allow valley regions of a curve indicative of a frequency characteristic of a combustion pressure wave generated by the multiple combustions to fall within respective ranges of a plurality of resonant frequency bands of a structure of an engine body of the engine, wherein the PCM is operable to increase the interval between the temporally-adjacent multiple fuel injections to 1.7&#xb1;0.1 msec.

Fuel injectin control method and fuel injection control device for compression self-ignition engine

The compression self-ignition engine fuel injection control device is configured to, during one combustion stroke, perform multiple fuel injections to induce multiple combustions in a cylinder. The fuel injection control device comprises a PCM () configured to set an interval between a pre-injection and a main injection in the multiple fuel injections, so as to allow valley regions of a curve indicative of a frequency characteristic of a combustion pressure wave generated by the multiple combustions to fall within respective ranges of a plurality of resonant frequency bands of a structure of an engine body of the engine, wherein the PCM is operable to increase a fuel injection amount of the pre-injection more largely as an engine load becomes lower at the same engine speed.

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Hiroshima, Japan

Takeshi Matsubara