Internal-combustion engines – Charge forming device – Exhaust gas used with the combustible mixture
Reexamination Certificate
2000-02-22
2001-09-04
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Charge forming device
Exhaust gas used with the combustible mixture
C701S108000
Reexamination Certificate
active
06283101
ABSTRACT:
TECHNICAL FIELD
This invention relates to a method and a device for controlling exhaust gas recirculation in an internal combustion engine, in particular a compression-ignition internal combustion engine, which has a crankcase, at least one cylinder and one cylinder head with an intake duct and an exhaust duct connectable via an exhaust gas recirculation duct, the rate of exhaust gas recirculation being controlled by a control device in dependence on operating parameters of the internal combustion engine, the control device having a basic characteristic map with the parameters speed n
e
of internal combustion engine and quantity m
f
of fuel delivered per working cycle and further a vehicle acceleration correction device generating a vehicle acceleration correction signal, and the base signals of the basic characteristic map being modifiable by correction devices that are engageable as necessary and generate correction signals.
BACKGROUND OF THE INVENTION
Such a method is known from German patent document DE-A 196 31 112, published Feb. 6, 1997, T. Shirakawa, inventor. According to this document, a control device for an internal combustion engine is made such that, upon detection of a change in the operating conditions of the engine or upon an acceleration, a retardation of the fuel injection timing control is predicted. In coincidence with a difference between an actual fuel injection time and the predicted nominal fuel injection time, a nominal exhaust gas recirculation range, that is, a quantity or rate of exhaust gas recirculation, is corrected.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of this invention to provide a method and a device for controlling exhaust gas recirculation in an internal combustion engine, which can take account of the most varied service conditions of an internal combustion engine.
This object is achieved by virtue of the fact that the vehicle acceleration correction signal is applied multiplicatively to the base signal, that the vehicle acceleration correction device takes account of the parameters
a) injection pump controller setpoint,
b) gas pedal position,
c) controller setpoint corresponding to smoke limit,
and that if b)>a) and a)>c), a disturbance variable is present, which correspondingly takes account of the evaluated parameters a) and c). Stored in the basic characteristic map are characteristic curves in terms of the above-cited parameters, which establish the base signals. At least in certain services of the internal combustion engine, exhaust gas recirculation can be controlled with these base signals alone, provision also being made that an “emergency program” is run in accordance with the base signals in case, for example, of a malfunction due to, for example, defective sensors for one or several correction devices. According to the present invention, in most applications of the internal combustion engine, the basic characteristic map is modified as necessary by correction devices generating correction signals. Thus provision is advantageously made for generally storing in the basic characteristic map the exhaust gas recirculation values for various internal combustion engines, these base signals then being subject to modification depending on the model and version of the internal combustion engine (cylinder number, power setting, etc.) and the other correction devices described in what follows. This design makes it possible always to use the same device and to keep the diversity of parts low. There is always a vehicle acceleration correction device that takes account of the parameters injection pump controller setpoint, gas pedal position and smoke limit. The current gas pedal position is then compared with the injection pump controller setpoint in one comparator, and the smoke limit is compared with the injection pump controller setpoint in one comparator. If the comparison in both comparators yields the result that specifiable settings are being exceeded, the output signal in each case is identified as a disturbance variable, the two output disturbance variables being combined in an AND element. In other words, only if a disturbance variable is present at both comparators is a further switch downstream of the AND element actuated. At the same time, the injection pump controller setpoint and the smoke limit are input to a divider and, according to the resulting value, a value for the degree of closure of the exhaust gas recirculation is derived from a subsequent evaluation curve. This value is then applied multiplicatively to the base signal if the presence of a disturbance variable is signaled to the aforementioned switch.
In development of the invention, there is a use correction device, which generates a use correction signal which is applied multiplicatively to the base signal. This use correction device thus quite generally takes account of the specified intended use of the internal combustion engine and establishes correction signals for such use, with which the base signals are superposed. Possible intended uses are, for example, the use of the internal combustion engine in a vehicle, an agricultural machine, a construction machine, or an implement.
In development of the invention, there is an internal combustion engine acceptance correction device, which likewise generates appropriate correction signals. Basic correction values are consequently stored in this correction device during the internal combustion engine acceptance procedure after manufacture and assembly, which correction values are quite specially tailored to the particular internal combustion engine acceptance procedure. These are understood to be basic values as to the model and version of the internal combustion engine.
Further, there is a vehicle data correction device. In this, relevant vehicle data, such as for example vehicle data and service field, can then be stored.
Further, there is an ambient pressure correction device, which finds use in particular when the internal combustion engine or the vehicle is in service in mountains.
In development of the invention, there is a coolant temperature correction device, which takes account of the internal combustion engine coolant temperature in controlling the exhaust gas recirculation.
Moreover, there is a dynamic correction device, which takes account of the mode of driving of the operator of a vehicle. This dynamic correction signal incorporates the speed of the internal combustion engine and the quantity of fuel delivered per working cycle, these both being used to determine whether a steady driving state or an extreme driving mode (continual alteration of gas pedal between zero position and full-load position) is in effect. If the presence of dynamic operation is identified in this device, a correction value is added to the base signal in the case of this device, in contrast to the signals mentioned above.
Downstream of all these correction devices is a device that verifies whether the engine brake of the vehicle is engaged. If so, exhaust gas recirculation is automatically reduced to zero or shut off entirely. Exhaust gas recirculation is likewise shut off during starting operation.
REFERENCES:
patent: 4455987 (1984-06-01), Sudbeck
patent: 4762107 (1988-08-01), Schoneck et al.
patent: 5063510 (1991-11-01), Jurgens et al.
patent: 5682864 (1997-11-01), Shirakawa
patent: 44 35 420 (1994-10-01), None
patent: 196 44 102 (1996-10-01), None
patent: 56-027055 (1981-03-01), None
patent: 60-192870 (1985-01-01), None
Hülsmann Bernd
Lutat Martin
Deutz AG
Hardaway/Mann IP Group Nexsen Pruet Jacobs & Pollard, LLC
Schwab Charles L.
Wolfe Willis R.
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