Denso Corporation

Nippondenso Co., Ltd.

Yoshihiro Majima

Yukihiro Yamashita

Makoto Miwa

Hisashi Iida

Jun Hasegawa

Noriaki Ikemoto

Keiji Wakahara

Kiyotoshi Oi

Masaei Nozawa

Masao Yonekawa

Toyoji Yagi

Kazuji Minagawa

Hideyuki Maeji

Sigenori Isomura

Shigenori Isomura

Haruyuki Urushihata

Masaomi Inoue

Junya Morikawa

Yoshinori Maegawa

Akira Ichikawa

Masakazu Yamada

Syujiro Morinaga

Noriaki Iwase

Takeshi Fujimoto

Tatsuya Oka

Takanori Takahashi

Hiroyuki Katsuta

Masayuki Tsutsumi

The ignition timing is sustained at an initial value during a predetermined time beginning at a start of an engine, and is retarded after the predetermined time is elapsed to heat a catalyst at an early time. The predetermined time ends when the negative pressure of an intake pipe or the negative pressure of a brake booster reaches to a predetermined value. That is, the predetermined time is a period, which begins at a start of the engine and ends when a proper negative pressure can be sustained in the brake booster. As a result, it is possible to assure a negative pressure in the brake booster at an early time and to reduce exhaust emission at a start of the engine simultaneously.

Control apparatus of internal combustion engine

A common rail fuel injection system has a fuel pump, a common rail, and an injector. The injector injects high-pressure fuel supplied from the common rail into an engine and leaks part of the high-pressure fuel. An electronic control unit (ECU) restricts a heat amount of the leak fuel of the injector based on a remaining amount of the fuel in a fuel tank. At that time, a target value of the fuel pressure in the common rail is changed to a lower value and the restriction of the fuel pressure is performed with the changed target value. Thus, decrease in generation torque of the engine against intension of a driver can be inhibited while protecting components such as the fuel injection valve.

Controller of pressure accumulation fuel system

A control unit employed in a variable valve timing apparatus vibrates a control signal for controlling an oil-pressure control valve. If the vibration center of the duty value of the control signal for driving the oil-pressure control valve lies in a dead band, the vibration takes the duty value to the outside of the dead center temporarily. Thus, even if the center value of the control signal lies in the dead band, the valve timing of the oil-pressure control valve changes with variations in control signal. As a result, the width of the dead band appears small or to have a value of zero. Accordingly, the response characteristic of variations in valve timing to the variations in control signal is improved. The vibration of the control signal is also effective for detection of a width of the dead band.

Control apparatus for device having dead band, and variable valve system

An emission control system has a catalyst and a sensor responding to a component of exhaust gas. In order to speed warming up the catalyst, the emission control system increases the amount of heat dissipated by exhaust gas. A diagnosis of the emission control system is carried out by determining whether the amount of heat dissipated by exhaust gas is sufficient or insufficient. The amount of heat dissipated by exhaust gas is represented by the length of time to an activated state of the sensor. In the diagnosis, the amount of heat generated by a heater provided in the sensor is taken into consideration.

Emission control system with catalyst warm-up speeding control

A valve timing control device for an internal combustion engine, in which upon cold start, combustion gas containing quench hydrocarbons and wet fuel is confined in a combustion chamber by advancing an exhaust valve close timing. This combustion gas is richer in hydrocarbons and wet fuel than is the gas produced after the engine has been warmed up. When the pressure in an intake line becomes lower than 600 mmHg, the exhaust valve close timing is retarded so as to recirculate post-combustion gas back to the combustion chamber. Then the unburned hydrocarbons in the post-combustion gas are involved in combustion again and their emission is reduced. Such gas recirculation and confinement to the combustion chamber are switched in accordance with a target valve underlap corresponding to the intake line pressure in the internal combustion engine.

Valve timing control device for internal combustion engine

Processing conditions are determined on the basis of an operation range. After IG-OFF, an intake valve opening timing is advanced to 20&deg; CA BTDC, and an exhaust valve closing timing is retarded to 20&deg; CA ATDC. By controlling the intake and exhaust valve timings as described above, it is possible to reduce the fuel sticking to the intake passage. Particularly in the case of cold engine starting before activation of the catalyst, it is possible to prevent direct exhaust of HC emissions and accordingly to reduce emissions because of the decreased amount of fuel sticking to the intake passage.

Control apparatus and method for internal combustion engine

During an operation to warm up a catalyst at an early time, an engine control apparatus adjusts an intake valve to a target opening position, which is set to provide a sufficient flow velocity of a flow of intake air flowing through the intake valve. Thus, fuel stuck on the intake passage is evaporated and, in addition, mixed gas in a combustion chamber is well agitated. Furthermore, the engine control unit controls a fuel injection period, a fuel injection timing and an ignition timing in accordance with the opening timing of the intake valve. Therefore, an amount of stuck fuel is reduced according to increase in the flow velocity of intake air.

Control apparatus for internal combustion engine

When control conditions are satisfied, an A/F value is estimated from an average value of rotation speed Ne and an increasing rotation speed &Dgr;Ne calculated. The estimated A/F value as a base is obtained from the average value of the rotation speed Ne, and a correction value for the estimated A/F value is obtained from the increasing rotation speed &Dgr;Ne. Then, a fuel increment/decrement correction coefficient &ggr; and an air increment/decrement correction coefficient &bgr; are calculated, and used in the control of A/F ratio toward a target A/F value based on a final estimated A/F value.

Fuel supply amount control apparatus for internal combustion engine

A catalyst is warmed up by a rapid heating control that retards ignition timing and increases an intake air amount. Then the warm up is completed or a transmission is shifted to a drive range, the ignition timing is gradually advanced and the intake air amount is gradually decreased. Therefore, an engine speed is smoothly changed from the rapid heating control to the normal control without a torque shock. Additionally, a beginning of the advancing of the ignition timing is delayed by a predetermined delay time relative to a beginning of the decreasing of the intake air amount. The decreasing of the intake air amount prevents undesirable increase of the engine speed caused by the advancing of the ignition timing.

Apparatus for controlling catalyst temperature and method for controlling catalyst temperature

An apparatus for detecting a condition of the burning in an internal combustion engine includes a burning-parameter controlling device for controlling a burning parameter operating on the burning in the internal combustion engine. A burning-condition detecting device operates for, in cases where the burning parameter is changed by the burning-parameter controlling device, sampling prescribed information for detecting a burning condition.

Apparatus for detecting a condition of burning in an internal combustion engine

If conditions for measuring a storage quantity of O in a catalyst are satisfied, a target air-fuel ratio is switched to a rich value after the end of a fuel-cut state. The quantity of a rich component contained in an exhaust gas flowing into a catalyst during a period of time period is calculated. The quantity of a rich component required to consume all O absorbed by the catalyst in the fuel-cut state is calculated. The computed quantity of a rich component is taken as a storage quantity of O in the catalyst. Since the air-fuel ratio of exhaust gas is changed to a rich value, to improve exhaust gas cleaning, during the computation of a storage quantity of O , the storage quantity of O in the catalyst can be computed without worsening emission of exhaust gas.

Catalyst deteriorating state detecting apparatus

An upstream-side catalyst is provided at a location in close to an exhaust manifold of an engine. An HC absorbent and a downstream-side catalyst are installed in series at the downstream side. With the upstream-side catalyst put in an inactive state, the HC absorbent absorbs HC having passing through the upstream-side catalyst. After the upstream-side catalyst has been activated, HC released from the HC absorbent is refluxed to the upstream side of the upstream-side catalyst through a reflux path to be removed by the upstream-side catalyst. At that time, the ECU executes catalyst-early-warming control right after an engine start in order to raise the temperature of the upstream-side catalyst at an early time so as to shorten the time it takes to activate the upstream-side catalyst.

Exhaust gas purification apparatus of internal combustion engine

An engine has variable timing mechanisms, which are controlled in starting an engine to set valve opening overlap of an intake valve and an exhaust valve around 30&deg; CA. In this case, internal EGR is actively conducted and fuel burning velocity within a cylinder becomes relatively slow and unburned fuel within the cylinder is emitted to an exhaust pipe to be post-burned by itself. Temperature of exhaust gas is maintained high and catalyst converters in the cold state may be activated quickly by actively implementing the post-burning within the exhaust pipe. Further, ignition timing is retarded, an air-fuel ratio is controlled at a slightly lean ratio and the exhaust valve is advanced. The effect of raising the temperature of exhaust gas by the post-burning may be realized more reliably by combining each of these controls.

Catalyst activation control system for engines

A plurality of catalysts are installed in an exhaust pipe, air-fuel ratio sensors or oxygen sensors are installed upstream and downstream of each catalyst, and the air-fuel ratio of the exhaust gas is feedback controlled to a target air-fuel ratio based on the output of the air-fuel ratio sensor located upstream of the upstream catalyst. In this the exhaust gas is sufficiently purified with the upstream catalyst alone when the exhaust gas flow rate is small, the oxygen sensor located downstream of the upstream catalyst is used as the downstream sensor for setting a target air-fuel ratio. Furthermore, when the exhaust gas flow rate increases, the amount of exhaust gas components passing through without purification in the upstream catalyst is increased. Therefore, the downstream sensor used for setting the air-fuel ratio is switched to the oxygen sensor located downstream of the downstream catalyst.

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Inuyama, Japan

Yoshihiro Majima