Internal-combustion engines – Charge forming device – Including exhaust gas condition responsive means
Reexamination Certificate
1999-08-31
2001-09-04
Argenbright, Tony M. (Department: 3747)
Internal-combustion engines
Charge forming device
Including exhaust gas condition responsive means
C123S458000, C123S479000
Reexamination Certificate
active
06283108
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel injection control arrangement for an internal combustion engine, in particular, to a fuel injection control arrangement for an internal combustion engine capable of detecting abnormality of a fuel pressure control means and/or fuel pressure detection means in the arrangement.
2. Conventional Art
When an internal combustion engine is operated under a condition of superlean air/fuel ratio, for example, 30~100 with respect to stoichiometric air/fuel ratio of 14.7, an extreme improvement in fuel economy and in exhaust gas clarification performance can be achieved, however, in order for operating the internal combustion engine at such superlean air/fuel ratio a highly pressurized fuel is necessary. In an operation of an internal combustion engine, a predetermined constant fuel pressure is frequently employed. However, in order to achieve a sufficient combustion performance it is preferable to vary the fuel pressure, for example, it is preferable to control the fuel pressure between 5 MPa and 10 MPa depending upon operation modes of an internal combustion engine concerned. For the purpose of this fuel pressure control, an electrically controllable pressure regulator for regulating the fuel pressure and a fuel pressure sensor for detecting the fuel pressure are used. However, in case when one of the electrically controllable fuel pressure regulator and the fuel pressure sensor fails, there poses a problem that the fuel pressure is placed out of control.
JP-A-10-47144 (1998), for example, discloses an abnormality diagnosis device for a fuel supply and injection arrangement which detects abnormality in fuel pressure and performs an abnormality diagnosis in the arrangement, wherein the abnormality diagnosis device for the fuel supply and injection arrangement, which includes a fuel pressurizing pump for pressurizing fuel in order to inject the pressurized fuel from a fuel injection nozzle into an internal combustion engine, a solenoid valve for adjusting amount of fuel to be fed and injected from the fuel injection nozzle into the internal combustion engine and a solenoid control means for outputting driving signals for the solenoid valve so as to control the amount of fuel at a predetermined amount, the abnormality diagnosis device is provided with a fuel pressure detection means for detecting the fuel pressure and an abnormality judging means of the solenoid valve based on variation of fuel pressure after being outputted of a valve open signal to the solenoid valve from the solenoid control means.
When an abnormal increase or decrease in fuel pressure in the fuel supply and injection arrangement or system for an internal combustion engine is detected, a failure which deteriorates an operating performance of the internal combustion engine can generally be discovered, however, a possible cause of the failure can not be judged by the detection of the fuel pressure abnormality. Further, if it is erroneously diagnosed as a failure, a corresponding element is erroneously exchanged.
SUMMARY OF THE INVENTION
In view of the above conventional art problems, one of the objects of the present invention is that when such as means for controlling fuel pressure and means for detecting fuel pressure are failed, abnormality thereby are detected immediately and in addition a possible failure element causing the abnormality is identified.
Another object of the present invention is that in response to the identification of a failed element a control amount of the fuel pressure control means is varied so as to continue control for the internal combustion engine.
Still another object of the present invention is that when the failed element is restored, the abnormality detection is cleared and the operation returns to a normal one, thereby the erroneous element exchange is prevented.
The above objects of the present invention are achieved by a control arrangement for an internal combustion engine, which comprises means for pressurizing fuel to be fed and injected into the internal combustion engine, the fuel pressure being one of parameters of determining amount of fuel; means for controlling the fuel pressure; means for detecting the fuel pressure; means for detecting an operating condition of the internal combustion engine; means for determining a target air/fuel ratio for the internal combustion engine depending on the detected operating condition of the internal combustion engine; means for detecting air/fuel ratio of the internal combustion engine; and an air/fuel ratio feed back control means for feeding back a feed back control amount depending on a deviation between the determined target air/fuel ratio and the detected air/fuel ratio, and which control arrangement further comprises an abnormality detection means which detects abnormality either in the fuel pressure control means or in the fuel pressure detection means when the fuel pressure detected by the fuel pressure detection means for the internal combustion engine is judged outside a predetermined range determined by a control amount fed for the fuel pressure control means, and performs a control for the internal combustion engine other than a normal control when the abnormality detection means detects an abnormality.
Further, the above objects of the present invention are achieved by the control arrangement for an internal combustion engine which uses a signal representing an air/fuel ratio status amount determined by making use of the air/fuel ratio for the internal combustion engine for detecting an abnormality either in the fuel pressure control means or in the fuel pressure detection means, and through detection whether or not the signal is within a predetermined range an abnormal element causing the abnormality is specified.
One aspect of the present invention is to provide a control arrangement for an internal combustion engine which comprises a fuel supply system for an internal combustion engine including means for pressurizing fuel to be fed and injected into the internal combustion engine, the fuel pressure being one of parameters of determining amount of fuel; means for controlling the fuel pressure; and means for detecting the fuel pressure; means for detecting an operating condition of the internal combustion engine; means for determining a target air/fuel ratio for the internal combustion engine depending on the detected operating condition of the internal combustion engine; means for detecting air/fuel ratio of the internal combustion engine; and an air/fuel ratio feed back control means for feeding back a feed back control amount determined by relating to a deviation between the determined target air/fuel ratio and the detected air/fuel ratio, and which control arrangement further comprises an abnormality diagnosis means for diagnosing abnormality in the fuel supply system based on the fuel pressure detected by the fuel pressure detection means and an abnormal element detection means for detecting a possible abnormal element in the fuel supply system based on an amount representing an air/fuel ratio status including the detected air fuel ratio and the air/fuel ratio feed back control amount when the abnormality diagnosis means diagnoses an abnormality in the fuel supply system.
Further, the present invention provides the control arrangement for an internal combustion engine in which the abnormality diagnosis means diagnoses an abnormality in the fuel supply system when the fuel pressure detected by the fuel pressure detection means for the internal combustion engine is judged outside a predetermined range determined by a control amount fed for the fuel pressure control means.
Still further, the present invention provides the control arrangement for an internal combustion engine in which the abnormal element detection means detects a possible abnormal element through detection whether or not the actual air/fuel ratio detected by the air/fuel ratio detection means for the internal combustion engine is within a predetermined range of th
Goto Ken-ichi
Hori Toshio
Matsufuji Koji
Toyohara Masahiro
Argenbright Tony M.
Crowell & Moring LLP
Hitachi , Ltd.
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