Nissan Motor Company Limited

Taisuke Shiraishi

Daisuke Tanaka

Koji Hiraya

Eiji Takahashi

Akihiko Kakuho

Morihiro Nagamine

Tomonori Urushihara

Tatsuya Yaguchi

Hirofumi Tsuchida

Isamu Hotta

Masaharu Kassai

Toshikazu Shiino

Takuma Suzuki

Kazuhisa Watanabe

Akira Tayama

Takashi Araki

Shinichi Okamoto

Hirofumi Maeda

A combustion chamber structure for an internal combustion engine includes a recessed portion formed in a pent roof of a cylinder head on an upstream side of a tumble flow with respect to a spark plug.

Combustion chamber structure for internal combustion engine

In determining an in-cylinder pressure by analyzing a secondary current detected by a secondary current detection resistor, an engine controller is configured to detect an engine revolution speed and a discharge duration during which the secondary current flows. The discharge duration is correlated with a gas pressure between electrodes of a spark plug at ignition timing, that is, an in-cylinder pressure, and is different depending on the engine revolution speed. The engine controller is further configured to estimate the in-cylinder pressure at ignition timing based on the engine revolution speed and the discharge duration. An amount of time-dependent change in mechanical compression ratio, caused by accumulation of deposits, is detected based on the estimated in-cylinder pressure at ignition timing.

Determining in-cylinder pressure by analyzing current of a spark plug

An ignition device for an internal combustion engine () includes a superpose voltage generation circuit () that, after the initiation of a discharge with the application of a discharge voltage by a secondary coil, applies a superpose voltage between electrodes of an ignition plug () in the same direction as the discharge voltage to continue a discharge current, and performs a superposed discharge in a superposed discharge activation range of high exhaust recirculation rate. Upon shift from the superposed discharge activation range of high exhaust recirculation rate to a superposed discharge deactivation range of low exhaust recirculation rate, the deactivation of the superposed discharge is delayed by a delay time &#x394;T. Although the exhaust gas recirculation rate becomes temporarily increased with decrease in intake air after the closing of an exhaust gas recirculation control valve, the superposed discharge is continued for the delay time &#x394;T so as to avoid misfiring.

Ignition control system for internal combustion engine and ignition control method

When an operating condition including load and speed of an internal combustion engine is in a prescribed low-speed high-load region, i.e., an energy suppression region, having a possibility causing pre-ignition, energization time TDWLMIN for the energy suppression region is selected as a primary coil energization time. In other normal regions, normal energization time TDWL is selected. Normal energization time TDWL has a characteristic such that the normal energization time shortens, as the engine speed increases. In a low speed region, a given energization time that can fulfill a discharge energy required in a high exhaust gas recirculation region is provided. Energization time TDWLMIN for the energy suppression region is constant regardless of engine speeds and relatively short, and is set to a level such that a coil generated maximum voltage does not exceed a withstand voltage of a spark plug even when no-discharge occurs due to pre-ignition.

Internal combustion engine ignition device and ignition method

In order to prevent an abnormal combustion due to oil, a restriction region (B) is designated on a low-speed and high-load side of an internal combustion engine (), and an opening of throttle valve () is restricted so that an engine operating condition is not observed within the restriction region (B). A predetermined designated inspection region (A) is set so as to include the restriction region (B), and it is judged whether or not the abnormal combustion actually occurred when the internal combustion engine () is running within the designated inspection region (A). If the abnormal combustion was detected, the restriction region (B) is expanded, meanwhile, if the abnormal combustion was not detected, the expanded restriction region (B) is gradually decreased. If the abnormal combustion occurred at a shorter interval than a threshold value, the restriction region (B) is expanded at once to a predetermined size.

Internal combustion engine control device, and control method

In an ignition device of an internal combustion engine which carries out ignition of an air-fuel mixture by repeatedly applying a voltage across electrodes of an ignition plug thereby producing a plurality of discharges, an improvement is proposed in which in the presence of gas flow of which direction is perpendicular to a direction that connects the electrodes with a shortest distance, a time interval between n-th time discharge and (n&#x2212;1)-th time discharge is so set that a discharge channel caused or proposed by the n-th time discharge is more extended in the gas flow direction than a discharge channel caused by the (n&#x2212;1)-th time discharge.

Internal-combustion engine ignition device and ignition method

An ignition unit () has a superimposed voltage generation circuit () that feeds, between electrodes of an ignition plug (), a superimposed voltage of the same direction as a discharge voltage, and in an operation range wherein an engine rotation speed is equal to or lower than a given speed and an engine load is equal to or lower than a given load, feeding of the superimposed voltage is carried out. Although the energization time for a primary coil () is basically set in accordance with the engine rotation speed, the energization time TDWLON for the superimposed voltage feeding is set shorter than the energization time TDWLOFF for the superimposed voltage non-feeding. With this, temperature increase of the ignition unit () caused by the feeding of the superimposed voltage is suppressed.

Ignition device for internal combustion engine and ignition method

An engine control apparatus has an electric discharge device, a voltage application device, a fuel supplying device, and a control unit. The electric discharge device includes a first electrode and a second electrode. The second electrode is arranged opposite the first electrode to produce radicals within a combustion chamber of an internal combustion engine by a non-equilibrium plasma discharge that is generated between the electrodes before autoignition of the air-fuel mixture occurs. The voltage application device is operatively coupled to the first electrode for applying a voltage between the first and second electrodes to generate the non-equilibrium plasma between the first and second electrodes. The fuel supplying device forms an air-fuel mixture inside the combustion chamber. The control unit is operatively coupled to the electric discharge device to set a discharge start timing of the electric discharge device to occur during an intake stroke of the internal combustion engine.

Engine control apparatus and method

An ignition device performs spark ignition to a fuel mixture in a combustion chamber () of an internal combustion engine () by using a spark plug (). The spark plug () includes a first electrode (), a second electrode (), and an insulating member () which is formed from dielectric substance and interposed between the first electrode () and the second electrode (). By impressing an alternating current between the first electrode () and the second electrode (), non-equilibrium plasma discharge between the insulating member () and one of the first electrode () and the second electrode () is promoted. Igniting the fuel mixture by the non-equilibrium plasma discharge achieves a high ignition performance is achieved with low energy consumption.

Non-equilibrium plasma discharge type ignition device

An internal combustion engine is provided that basically comprises a cylinder block, a cylinder head, a piston, an auxiliary chamber partition wall and a spark plug. The auxiliary chamber partition wall is coupled to the cylinder head and extending toward the main chamber to form an auxiliary combustion chamber inside an area enclosed by the auxiliary chamber partition wall. The auxiliary chamber partition wall has at least one jet aperture through which the auxiliary combustion chamber fluidly communicates with the main combustion chamber. A tip portion of the auxiliary chamber partition wall that faces toward the piston has a smaller wall thickness than other portion of the auxiliary chamber partition wall.

Internal combustion engine with auxiliary combustion chamber

An internal combustion engine is provided that basically comprises a combustion chamber, an electric discharge unit and a controller. The combustion chamber receives a mixture of fuel and air that is caused to undergo compression self ignition. The electric discharge unit is provided inside the combustion chamber to generate an electric discharge for conducting combustion inside the combustion chamber. The controller is configured to control a voltage applied to the electric discharge unit. The controller is configured to control the electric discharge unit such that a non-thermal plasma can be formed without incurring a transition to arc discharging, and to control the quantity and distribution of an activated air-fuel mixture inside the combustion chamber in accordance with an operating condition of the internal combustion engine.

Internal combustion engine and combustion control method

A NOx emission reduction apparatus includes high-temperature EGR gas supply means for supplying a high-temperature EGR gas into an engine cylinder, low-temperature EGR gas supply means for supplying a low-temperature EGR gas into the engine cylinder and very-low-load operation control means for, as an engine load decreases in a very-low-load range, increasing an EGR rate of the high-temperature EGR gas and decreasing an EGR rate of the low-temperature EGR gas for stable engine operations and NOx emission reduction.

NOx emission reduction apparatus

An exhaust emission control apparatus for an internal combustion engine includes a fuel injection valve placed substantially at a midpoint above a combustion chamber of the engine; a piston having an outer cavity formed substantially in a midsection of an upper surface of the piston and an inner cavity formed in a bottom surface of the outer cavity; an ignition plug placed in a region right above the outer cavity; an exhaust purifying catalyst provided in an exhaust passage of the engine; and a controller. This controller is configured to carry out a stratified charge combustion when a temperature rise for the exhaust purifying catalyst is required, by forming air-fuel mixture which is richer than stoichiometric ratio and is able to be ignited by the ignition plug, within the outer cavity and in an area substantially right above the outer cavity, from a fuel injected through the fuel injection valve.

Exhaust emission control apparatus and method for internal combustion engine

A direct fuel injection engine is provided that an appropriate stratified fuel-air mixture is formed to conduct good stratified combustion over a wide range of loads. The engine has a fuel injection valve that is arranged at an upper surface of the combustion chamber on or near the center reciprocation axis of the piston and oriented such that the injection center axis of the fuel stream injected therefrom is slanted with respect to the center reciprocation axis of the piston. The piston is disposed in the combustion chamber to move along a cylinder center axis. The piston has a top surface having a first outer cavity having a first cavity center axis, and a second inner cavity located in the outer cavity. The second inner cavity has a second cavity center axis offset from the cylinder center axis of the piston in a direction perpendicular to the cylinder center axis.

Direct fuel injection engine

A fuel injection control device for a direct fuel injection engine is configured to selectively control a fuel injection valve, which is configured and arranged to directly inject a first fuel stream per cycle into a combustion chamber, to use a first fuel injection timing when the controller determines that a stratified air-fuel mixture will be difficult to form during a second fuel injection timing based on a determination of an engine operation parameter by at least one sensor. The first fuel injection timing is set to control the injection valve to inject the first fuel stream during an intake stroke while a piston in the combustion chamber is approximately at an intake top dead center position such that a majority of the first fuel stream injected from the fuel injection valve is received inside a cavity formed on the piston.

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Yokohama, Japan

Taisuke Shiraishi