Abstract: A fuel supply system has an in-tank module. The in-tank module is provided with a pump, a filter, a pressure regulator and a pressure sensor detecting a fuel pressure. The pressure sensor is disposed on or at a vicinity of the fuel pump so that the pressure sensor easily detects a pulsation component due to the pump. A fuel pump controller includes a speed detection module which detects the rotation speed of the fuel pump based on a cycle of the pulsation component of the pressure detected by the pressure sensor. Thus, the rotation speed of the fuel pump can be indirectly detected by means of the pressure sensor.

Abstract: A fuel supply system has an in-tank module. The in-tank module is provided with a pump, a filter, a pressure regulator and a pressure sensor detecting a fuel pressure. The pressure sensor is disposed on or at a vicinity of the fuel pump so that the pressure sensor easily detects a pulsation component due to the pump. A fuel pump controller includes a speed detection module which detects the rotation speed of the fuel pump based on a cycle of the pulsation component of the pressure detected by the pressure sensor. Thus, the rotation speed of the fuel pump can be indirectly detected by means of the pressure sensor.

Abstract: A nitrogen-enriched gas supplying device includes a bypass passage and a gas separating membrane, so as to supply nitrogen-enriched gas to an internal combustion engine. The bypass passage introduces a part of exhaust gas from an exhaust passage of the internal combustion engine into an intake passage of the internal combustion engine. The gas separating membrane is arranged in the bypass passage. The gas separating membrane is configured to separate carbon dioxide from exhaust gas introduced into the bypass passage.

Abstract: An integrated value of discharge quantity of a fuel pump is used as a parameter evaluating a pressure loss of a fuel filter. A target discharge quantity is obtained by correcting a fuel quantity required by an engine with a filter pressure loss correction amount corresponding to an integrated value of the discharged quantity. A target rotational speed of the fuel pump is computed based on the target discharge quantity, so that the target rotational speed is corrected in accordance with the pressure loss of the fuel filter. Alternatively, the target rotational speed may be corrected in accordance with a deterioration degree of the fuel pump.

Abstract: A fuel pump control device is for a fuel supply system for an engine. The system includes a fuel tank, a subtank, a fuel pump pumping fuel in the subtank for supply to the engine, a pressure regulator regulating fuel pressure from the fuel pump within a set pressure, and a jet pump pumping fuel in the fuel tank into the subtank through pumping action by a fuel ejection flow to the fuel tank through a return pipe of the regulator. The device includes a fuel level detecting unit for detecting fuel tank level and a control unit for controlling fuel discharge amount from the fuel pump. The control unit sets jet pump drive correction amount of fuel for driving the jet pump based on the fuel tank level. The control unit increases the fuel discharge amount from the fuel pump by the correction amount to drive the jet pump.

Abstract: An intake control device of an internal combustion engine in which an intake path of each cylinder is partitioned into an upper and a lower path and a tumble control valve and an intake pressure control valve are provided to open/close the upper path and lower path respectively. In a given driving condition, the intake air flow velocity in the lower path is increased by closing the tumble control valve, thereby generating a tumble flow in the combustion chamber. In this process, the intake pressure control valve is opened around start of an intake stroke and closed around its end to make intake pressure downstream of the intake pressure control valve higher than upstream of it to increase the difference between upstream and downstream intake pressures in the intake stroke. This increases the intake air flow velocity in the lower path and intensifies the tumble flow in the combustion chamber.

Abstract: A correction apparatus for correcting an output of an oxygen sensor installed in an exhaust pipe of an internal combustion engine to measure the concentration of oxygen contained in exhaust gas. The apparatus works to execute a fuel cut operation to bring the pressure in the exhaust pipe to the atmospheric pressure and enters an under-atmosphere correction mode to sample an output of the oxygen sensor and determine a correction factor compensating for a deviation of the sampled output from a reference value representing an actual concentration of oxygen. The apparatus also works to calculate the pressure in the exhaust pipe after start of the fuel cut and determine whether the under-atmosphere correction mode is to be entered or not based on the pressure of exhaust gas, thereby ensuring the accuracy in correcting the output of the oxygen sensor regardless of a variation in the pressure of exhaust gas.

Abstract: A correction apparatus for correcting an output of an oxygen sensor installed in an exhaust pipe of an internal combustion engine to measure the concentration of oxygen contained in exhaust gas. The apparatus works to execute a fuel cut operation to bring the pressure in the exhaust pipe to the atmospheric pressure and enters an under-atmosphere correction mode to sample an output of the oxygen sensor and determine a correction factor compensating for a deviation of the sampled output from a reference value representing an actual concentration of oxygen. The apparatus also works to calculate the pressure in the exhaust pipe after start of the fuel cut and determine whether the under-atmosphere correction mode is to be entered or not based on the pressure of exhaust gas, thereby ensuring the accuracy in correcting the output of the oxygen sensor regardless of a variation in the pressure of exhaust gas.

Abstract: An intake control device of an internal combustion engine in which an intake path of each cylinder is partitioned into an upper and a lower path and a tumble control valve and an intake pressure control valve are provided to open/close the upper path and lower path respectively. In a given driving condition, the intake air flow velocity in the lower path is increased by closing the tumble control valve, thereby generating a tumble flow in the combustion chamber. In this process, the intake pressure control valve is opened around start of an intake stroke and closed around its end to make intake pressure downstream of the intake pressure control valve higher than upstream of it to increase the difference between upstream and downstream intake pressures in the intake stroke. This increases the intake air flow velocity in the lower path and intensifies the tumble flow in the combustion chamber.

Abstract: A gas sensor such as an O2 sensor or NOx sensor used in measuring an air-fuel ratio of a mixture supplied to an automotive internal combustion engine. The gas sensor is equipped with a sensor element and a cover assembly. The cover assembly is coated with a hydrophilic film having a water wettability of 70° or less, as expressed by a water contact angle, or reformed to have a surface having a water wettability of 70° or less. This minimizes exposure of the sensor element to water without sacrificing the response of the gas sensor to avoid water-caused cracks in the sensor element.

Abstract: An evaporated fuel gas purging system performs breakdown analysis without deterioration of drivability and exhaust emission even when the amount of purged fuel gas is large. During introduction of negative pressure into the purge system, a control value DUTY sets opening of a purge control valve and a purge flow amount GPG is derived from a map based on differences in the control value DUTY, atmospheric pressure and intake pipe pressure. Thereafter, a purge ratio PGR is calculated from intake air GA and purge flow GPG (PGR=GPG/GA), and a fuel injection correction value FAFLEAK=PGR.times.(FGPGAV-1).times.K1 is calculated, with FGPGAV-1 being the air-fuel ratio feedback correction deviation per 1% purge ratio, and K1 being an error correction coefficient. Then, the fuel injection correction FAFLEAK is guard-processed to maintain it below an upper limit guard value KFLEAKMX.

Abstract: The digital control unit of the present invention relates to improvements in what is called recent control, and more particularly relates to the idle rotating speed control unit of an internal combustion engine in which the idle rotating speed can be quickly converged to the target rotating speed in the case where a load given from the outside varies. Especially, when the value of the state variable is reversely calculated from the state in which open loop control is conducted, the initial value can be accurately determined.

Abstract: Deterioration of a catalyst of a catalytic converter of an internal combustion engine is detected, during negative feedback control of the air-fuel ratio based on an output signal from at least one of a pair of O.sub.2 sensors disposed respectively upstream and downstream from the catalyst in the exhaust system. Detection is executed after changing the feedback period, which is the period of alternation of a feedback correction coefficient used to control the fuel injection quantity, with the change in period being such as to provide improved accuracy of detection of catalyst deterioration. The change may consist of a single step change, in which the feedback period is set to a specific predetermined value at which the output signal amplitude from the downstream sensor, or the phase difference between the two sensor output signals, should be within predetermined limits if the catalyst is in satisfactory condition.

Abstract: An apparatus for detecting a purification factor of a catalyst for purifying an exhaust gas of an internal combustion engine comprises a catalyst disposed in an exhaust system of the internal combustion engine for purifying an exhaust gas, first and second air-fuel ratio sensors disposed upstream and downstream of the catalyst for detecting air-fuel ratios, respectively, a response delay time difference detecting device for detecting differences in response delay time between the first and second air-fuel ratio sensors in respective different operation states of the engine, a purification factor detecting device for detecting a purification factor of the catalyst on the basis of a deviation between the first and second response delay time differences detected in respective different operation states of the engine.