Denso Corporation

Nippondenso Co., Ltd.

Naoki Yoshiume

Makoto Miwa

Yukihiro Yamashita

Shigenori Isomura

Hisashi Iida

Noriaki Ikemoto

Makoto Tanaka

Masaaki Nakayama

Kiyotoshi Oi

Kazuji Minagawa

Keisuke Yanoto

Masahiko Yamaguchi

Shigeru Takeuchi

Shujiro Morinaga

Kosuke Nakano

Akira Ando

Wataru Nagashima

Yuri Takahashi

Shuujirou Morinaga

A control device for controlling a fuel injection in an internal combustion engine provided with a fuel injection valve has a driving portion supplying an electric power to a terminal of the fuel injection valve so as to drive the fuel injection valve to be opened; a current detecting portion detecting a drive current flowing through the fuel injection valve when the fuel injection valve is driven to be opened; a voltage detecting portion detecting a terminal voltage of the terminal of the fuel injection valve; a correction portion correcting the electric power supplied by the driving portion so that an actual value of the drive current detected by the current detecting portion agrees with a target value; a valve close detecting portion detecting a valve closing timing of the fuel injection valve based on the terminal voltage detected by the voltage detecting portion in a condition where the electric power supplied by the driving portion is corrected by the correction portion.

Device for controlling fuel injection in internal combustion engine

An air-fuel ratio sensor monitor is provided which is designed to monitor reactive characteristics or response rates of an air-fuel ratio sensor when an air-fuel ratio of a mixture to an internal combustion engine is changing to a rich side and to a lean side. The monitored response rates are used in determining whether the sensor is failing or not, in determining the air-fuel ratio of the mixture accurately, or in air-fuel ratio control of the engine.

Air-fuel ratio sensor monitor, air-fuel ratio detector, and air-fuel ratio control

When the output of the AFR ratio sensor is stable in a steady operating state, the amount of fuel is increased by step inputting to detect a point where the gradient of change in the sensor output exceeds a threshold value as a point of start of change. The time from the timing of increasing the fuel until the point of start of change is detected as a dead time. A response time is calculated until the amount of change in the sensor output reaches a predetermined ratio of the amount of change (AA&#x2212;BA) of up to the steady value AA of the sensor output after the amount of the fuel is increased from the steady value BA of the sensor output before the amount of the fuel is increased. The fail condition in the AFR ratio sensor is determined based on the dead time TA and the response time TB.

Device for detecting response characteristics of sensor

An air-fuel ratio detected by an air-fuel ratio sensor is periodically varied by executing a PI control. During the PI control, a time period in which the detected air-fuel ratio passes through a predetermined rich-side range is defined as a rich-side time constant, and a time period in which the detected air fuel ratio passes through a predetermined lean-side range is defined as a lean-side time constant. A rich-side time delay represents a time period in which an air-fuel correction amount is increasingly corrected to exceed a rich-side threshold, and a lean-side time delay represents a time period in which the air-fuel correction amount is decreasingly corrected to exceed a lean-side threshold. These time constants and time delays are compared with a determining value to diagnose degradation of an air-fuel ratio sensor.

System for diagnosing degradation of air-fuel sensor

An engine has an upstream-side catalyst and a downstream-side catalyst. First and second air-fuel ratio sensors are provided on the upstream and downstream sides of the upstream-side catalyst, respectively. A third air-fuel ratio sensor is provided on the downstream side of the downstream-side catalyst. The deteriorating state of the upstream-side catalyst is diagnosed during a period of time in which the third sensor is outputting a voltage in a predetermined range, and the air-fuel ratio is controlled to maintain the voltage output of the third sensor in the predetermined range during the period of time to diagnose the deteriorating state of the upstream-side catalyst.

Apparatus for detecting deterioration of exhaust gas purifying catalysts

A fuel transfer model of a fuel supply system is used to set and control the fuel pump of a return less fuel injection system. The model simulates characteristics of the fuel pump, fuel pressure transfer delay of fuel supply conduits and fuel pressure variation characteristics such as caused by expansion and compression of the fuel supply conduit volume due to an elastic coefficient and the like. The fuel pump model simulates a torque applied to the fuel pump motor, inertia, and the relationships between pump rotational speed, fuel pressure and fuel pump discharge amounts. A compensation control arithmetic calculation model may be derived from inverse calculation based on this fuel transfer model. The compensating current obtained from such an arithmetic model provides compensation for control of the fuel pump by adding a first value obtained by waveform shaping (through a first differentiation of the fuel injection amount) and a second value obtained by waveform shaping (through a second differentiation of the fuel injection amount).

Fuel feeding apparatus with response delay compensation

Electric current to a fuel pump in an engine fuel supply system is controlled so that a deviation in the number of pump rotations between a predetermined reference number of rotations of the fuel pump and an actual number of rotations thereof is within a predetermined range. When the deviation exceeds a predetermined range, it is determined that the fuel supply system is abnormal and at this time the operation of the fuel pump is limited. In this manner, the electric power consumed by the fuel pump is reduced because excess fuel is not circulated in the fuel supply system, thus accomplishing an improved reliability.

Fuel supply apparatus having abnormality detecting function

In a fuel pump control, until a rotational speed of an electrically-driven fuel pump rises to a predetermined speed, an electric current supplied to the fuel pump at an engine starting is increased higher than that normally supplied after engine starting thereby causing fast build-up of the fuel pressure. After the fuel pump reaches the predetermined speed, the electric current is decreased to a normal after-start current thereby suppressing a fuel pressure overshoot and resulting overrich mixture. Alternatively, a fuel pump speed is raised by the voltage control first at an engine starting operation, while switching the voltage control to the current control intermittently to detect the voltage applied to the fuel pump. When the detected voltage reaches a first predetermined voltage, the fuel pump speed is controlled exclusively by the current control.

Fuel pump control with control mode switching between before and after

In a fuel supply system employing a returnless fuel pipe arrangement, a relief valve is provided at a discharge side of a fuel pump. The relief valve is opened when fuel pressure in the fuel pipe arrangement becomes no less than a system protective pressure, so as to relieve the fuel pressure to protect the system. The relief valve is also arranged to be open when the fuel pressure in the fuel pipe arrangement becomes higher than a target fuel pressure by a predetermined value or when the fuel cut is performed. Thus, the fuel pressure in the fuel pipe arrangement is lowered. Thereafter, when the fuel pressure in the fuel pipe arrangement is lowered to a pressure near the target fuel pressure, the relief valve is arranged to be closed so that the fuel pressure in the fuel pipe arrangement is held substantially at the target fuel pressure.

Fuel supply for international combustion engine

Throttle valve opening and engine rotational speed are detected to estimate intake air pressure. Fuel consumption Q is estimated from the estimated intake air pressure. Fuel pump drive voltage is calculated from estimated intake air pressure and estimated fuel consumption through a data map. This map is set in advance from data measured experimentally. By thus driving the fuel pump, it can be controlled at an earlier (i.e., advanced) relative time by taking the response time delay of the control system and the fuel pump into consideration.

Fuel supply control for internal combustion engine by intake air

In a fuel supply system for an internal combustion engine, a feedback correction amount relative to a reference control value for a fuel pump is derived based on a deviation between an actual fuel pressure detected by a pressure sensor and a target fuel pressure. Since the feedback correction amount is controlled to be around zero during normal operation of the system, it is checked whether the feedback correction amount is within a given range. If negative, an occurrence of abnormality in the system is determined when a residual fuel amount in a fuel tank is no less than a criterion value and further when a vehicle is not running on a rough road. When the occurrence of abnormality is determined, a failure flag is set to ON while a failure determination enabling flag is reset to OFF so as to prohibit execution of a given other failure determination process such as a misfire detection process.

Fuel supply system for internal combustion engine

A fuel cut-off operation is delayed until a predetermined delay time period elapses after a fuel cut-off condition is satisfied. During the delay period, the voltage for driving a fuel pump is gradually dropped to decrease the rotation speed of the fuel pump gradually. Thus, the discharge pressure of the fuel pump is low and hence the rise of a fuel pressure immediately after the fuel cut-off operation starts can be prevented. After the fuel cut-off condition, updating of a fuel pressure feedback correction amount is prohibited until the fuel cut-off operation terminates. In this manner, a feedback control immediately after the fuel cut-off operation terminates is executed by using the feedback correction amount used immediately before the fuel cut-off condition to prevent the drop of the fuel pressure immediately after the fuel cut-off operation terminates. Thus, the fuel pressure can be maintained at a target fuel pressure.

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Takahama, Japan

Naoki Yoshiume