Internal-combustion engines – Combustion chamber means combined with air-fuel mixture...
Patent
1994-10-06
1996-04-09
Argenbright, Tony M.
Internal-combustion engines
Combustion chamber means combined with air-fuel mixture...
73 3503, F02P 515
Patent
active
055051766
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a valve seating noise discriminating system for an engine in which a valve system includes a variable valve operating mechanism for selectively changing statuses of intake and exhaust valves under the control of a control unit so as to establish a selected target operation mode of the engine. The valve seating noise discriminating system serves to prevent engine ignition timing from being affected by valve seating noises.
DESCRIPTION OF THE RELATED ART
There are known engines which include: a variable valve operating mechanism for selectively operating low or high speed cams at appropriate timing so as to increase engine output depending upon engine operating conditions; or a variable valve operating mechanism for selectively operating low or high speed cams, operating valves by the selected cams, and allowing a partial cylinder operation mode by interrupting supply of intake air and fuel to only a part of cylinders, thereby increasing engine output and reducing fuel consumption.
A control unit for such variable valve operating mechanisms sets various operation modes according to engine operating condition information. For instance, some of the cylinders are disconnected in a partial cylinder operation mode by de-activating intake and exhaust valves of such cylinders and interrupting fuel supply thereto. When the engine is taken out of the partial cylinder operation mode, the disconnected cylinders become active, meaning that their intake and exhaust valves are activated and fuel is supplied thereto. Further, in a full cylinder operation mode (with all the cylinders activated) at a low engine speed, low speed cams are used to operate the intake and exhaust valves so as to increase volume efficiency and output of the engine. Conversely, high speed cams are used to operate the valves in the full cylinder operation mode at a high engine speed, thereby increasing the volume efficiency and the output of the engine.
Generally, a control system of an internal combustion engine periodically receives various pieces of engine operating information from sensors, calculates values for controlling the engine operation according to the received operational data, activates actuators on the basis of outputs corresponding to the calculated values, and controls various mechanisms accordingly.
In the foregoing internal combustion engine, a quantity of intake air (A/N) to be introduced into combustion chambers of the engine is regulated according to the throttle valve opening. Fuel is supplied into the combustion chambers according to the intake air quantity commensurate with a current engine speed and throttle opening. Then, ignition is controlled to be performed at the timing determined depending upon the intake air quantity and engine speed.
There is a so-called speed-density type engine, in which an amount by which to advance the ignition timing is calculated on the basis of a pressure in an intake air pipe. In the speed-density type engine, it is not necessary to detect the intake air quantity by using an air flow sensor or the like, but it is sufficient simply to connect a pipe for introducing the pressure in the intake air pipe to an air pressure sensor. This configuration relatively relieves an air intake system from an intake air resistance, and is advantageous in reducing the cost of the sensor.
With the speed-density type engine, ignition timing is calculated on the basis of reference ignition timing .theta..sub.b prepared in map form. The reference ignition timing .theta..sub.b corresponds to an engine speed Ne and an intake air flow pressure Pb which is used in place of an intake air quantity A/N. Actual reference ignition timing .theta..sub.b is calculated on the basis of a current engine speed Ne and the intake air pressure Pb, and is corrected according to an amount .theta..sub.k to retard the ignition timing so as to derive target ignition timing .theta..sub.adv.
To calculate the angle of retard .theta..sub.k, a knocking sensor detects vibrations which are
REFERENCES:
patent: 4476709 (1984-10-01), Hattori et al.
patent: 4640250 (1987-02-01), Hosaka et al.
patent: 5136998 (1992-08-01), Deutsch
Ishii Dairoku
Iwata Toshio
Argenbright Tony M.
Mitsubishi Jidosha Kogyo Kabushiki Kaisha
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