Nissan Motor Company Limited

Takashi Aramaki

Masato Kobayashi

Takeshi Tsuyuki

Hideyuki Tamura

Katsuhiko Kawamura

Osamu Matsuno

Toshio Takahata

Hirofumi Yano

Jun Nakanowatari

Hiroya Ishii

Chiaki Saito

Fuel vapor in a fuel tank () is purged into an intake passage () of an engine () through a purge vent (). The controller () determines whether a leak is present in a purge vent from the fuel tank () to a purge control valve (). The determination process comprises a pull-down process in which a pressure in the purge vent is reduced using a negative pressure in the intake passage () and a leak-down process of sealing the purge vent at the reduced pressure and monitoring the pressure variation. The controller () calculates an error equivalence amount (DVPII), a pressure component corresponding to sloshing in the fuel tank () during the leak-down process, and determines the presence of a leak in a highly accurate manner based a corrected pressure (DVPA) in which the monitored pressure variation is corrected using the error equivalence amount (DVPII) (S).

Monitoring of fuel vapor pressure

In a device for judging of misfire of an internal combustion engine from a variation of crankshaft rotational speed during combustion stroke of each cylinders, a measurement period for measurement of crankshaft rotational speed at a cylinder is set by counting a predetermined number of first signals indicative of a predetermined rotational angle of a crankshaft firstly on the basis of a second signal indicative of a reference position of a camshaft and secondly and onward on the basis of the first signals used for setting the previous measurement section.

Device for detecting misfire of internal combustion engine

In case of trouble of a secondary air supply system, supply of an additional amount of fuel to an intake system and supply of secondary air to an exhaust system at the time of a particular engine operating condition such as an idling condition are stopped for regulating an air-fuel ratio closer to a stoichiometric value.

Means for preventing exhaust emission from being deteriorated in case of

An engine misfiring detection system includes a crank angle sensor for generating a reference pulse representative of a reference crank angle position in each cylinder of the engine, and a ring gear sensor for monitoring a magnitude of crank angle rotated from the reference crank angle position so as to define a first crank angle position required for starting an angular velocity measurement for an engine crankshaft and a second crank angle position required for ending the angular velocity measurement. A controller is provided to determine an engine misfiring state on the basis of fluctuations in a measuring time reaching from the first crank angle position to the second crank angle position. The controller variably sets the first and second crank angle positions in response to changes in an ignition timing of the engine. The controller determines a tooth defect in the ring gear on the basis of a ratio of said measuring time and a time interval necessary to reach from the reference crank angle position in relation to a firing cylinder to the reference crank angle position in relation to the subsequent cylinder.

Misfiring detection system for internal combustion engines

A self-diagnosing fuel-purging system includes a plurality of temperature sensors for detecting temperatures of an adsorbent in a fuel processing apparatus at different points. The system causes fuel previously adsorbed onto the adsorbent to be purged, and then, determines the state of the fuel adsorbed onto the adsorbent on the basis of the temperatures detected by means of the temperature sensors while fuel-purging is stopped. After the state of the fuel adsorbed onto the adsorbent becomes a predetermined state, the system determines abnormality in itself on the basis of temperature drop of the adsorbent detected by at least one of the temperature sensors while performing fuel-purging.

Self-diagnosing fuel-purging system used for fuel processing system

A failure checking apparatus for use with an internal combustion engine associated with an evaporated fuel purging unit having a canister adapted to accumulate evaporated fuel from a fuel tank. Communication is provided between the canister and the engine to introduce the evaporated fuel from the canister to the engine. The communication is interrupted to permit the canister to accumulate evaporated fuel from the fuel tank when a parameter related to a rate of evaporated fuel produced in the fuel tank exceeds a predetermined value. The communication is introduced into the canister and resumed to permit evaporated fuel to be introduced from the canister to the engine a predetermined period of time after the communication is interrupted. An air/fuel ratio at which the engine is operating is sensed for detecting a first value representing the air/fuel ratio when the communication is held interrupted and a second value representing the air/fuel ratio after the communication is resumed. A failure signal is produced, based upon a difference between the first and second air/fuel ratio values, to indicate that a failure occurs in the evaporated fuel purging unit.

Apparatus for checking failure in evaporated fuel purging unit

In an exhaust emission control system for an internal combustion engine, a secondary air is selectively introduced into an exhaust passage at a first position upstream of a catalytic converter. A failure detection system utilizes a plurality of temperatures of an exhaust gas for detecting a failure of the exhaust emission control system. A first temperature is derived at a second position between the first position and the catalytic converter when the secondary air is introduced into the exhaust passage at the first position. A second temperature is derived at the second position when no secondary air is introduced into the exhaust passage at the first position. By comparing the first and second temperature, it is detected whether the exhaust emission control system includes a failure. Third and fourth temperatures may also be derived at a third position located inside or downstream of the catalytic converter, which respectively correspond to the first and second temperatures. By comparing a difference between the first and third temperatures and a difference between the second and fourth temperatures, it is detected whether the exhaust emission control system includes a failure.

Exhaust emission control failure detection system for internal

An apparatus for and a method of diagnosing an EGR system are disclosed. A temperature within an EGR passage and a rise in temperature within the EGR passage are detected or determined by calculation. When the temperature and the temperature rise are lower than predetermined values, respectively, when the engine running condition falls in a predetermined range (a diagnosis area), it is determined that the EGR system is in trouble.

Apparatus for and method of diagnosing exhaust gas recirculation system

A method and apparatus for diagnosing a presence or absence of failure in an idle switch installed in an internal combustion engine in which, a throttle valve of an internal combustion engine is associated with the idle switch. The throttle valve installed in the engine is usually displaced to a fully closed while the engine at least once is during each period of continuous operation, a counter is advanced whenever the engine has started and is cleared when receiving an activation signal from the idle switch, if the idle switch functions normally, a count value of the counter reaches zero by the time the engine has stopped. If the idle switch fails, the count value is advanced whenever the engine is operated and no signal from the idle switch is received. When the count value reaches a predetermined value, an alarm informing the failure of the idle switch is produced.

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Kanagawa, Japan

Takashi Aramaki