Electronic engine control system

• US 6,212,467 B1
• Filed: 05/05/1999
• Issued: 04/03/2001
• Est. Priority Date: 05/05/1998
• Status: Expired due to Term

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Daimler Chrysler Company LLC (Stellantis NV)
• Inventors: Guzella, Lino, Koch, Charles Robert, Scherer, Matthias
• Primary Examiner(s): WOLFE JR, WILLIS RAY
• Application Number:
  US09/304,822
• Time in Patent Office: 699 Days
• Field of Search: 701/101, 701/102, 701/103, 701/108, 123/568.11, 123/568.21, 60/605.2
• US Class Current: 701/103
• CPC Class Codes: F02D 21/08 the other gas being the exhaust gas of engine
• CPC Class Codes: F02D 41/0062 Estimating, calculating or determining the internal EGR rate, amount or flow
• CPC Class Codes: F02D 41/0072 Estimating, calculating or determining the EGR rate, amount or flow sensors in EGR systems F02M26/45
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

An electronic engine control system for an internal-combustion engine has a computer with programs stored therein and interacts with a sensor system to determine a residual gas fraction in a combustion space of the engine. The engine control system generates a signal value, which correlates with the current residual gas fraction, from a signal value which is generated by the engine control system and which correlates with a current air/fuel mass ratio of a carbureted fuel fed to the combustion space, and from a signal value which is sensed by the sensor system and which correlates with a current air/fuel mass ratio of an exhaust gas discharged from the combustion space after the combustion.

Claims

1. An electronic engine control system for an internal-combustion engine which has a computer and a memory with programs filed therein which interact with a sensor system,

based on a signal value which is generated by the engine control system and which represents an actual current air/fuel mass ratio of a carbureted fuel fed to a combustion space of the engine, and on a signal value sensed by the sensor system which correlates with a current air/fuel mass ratio of an exhaust gas discharged from the combustion space of the engine after a combustion, the engine control system generates a signal value which represents a current exhaust gas mass fraction which together with the carbureted fuel fed to the combustion space, forms a content of the combustion space after a feeding of carbureted fuel and prior to a combustion.

2. An electronic engine control system according to claim 1 wherein said exhaust gas mass fraction is a residual gas fraction.

3. The engine control system according to claim 1, wherein:

as a function of the signal value which represents a current residual gas fraction, the engine control system adjusts engine operation when the engine control system determines existence of engine operation with an extrastoichiometric air/fuel mass ratio in the carbureted fuel.

4. Engine control system according to claim 1, wherein the sensor system includes a λ

-probe arranged behind one of the combustion space and the engine, in an exhaust gas system.

5. Engine control system according to claim 1, wherein, to influence engine operation, the engine control system varies at least one of an air/fuel mass ratio of carbureted fuel, an exhaust gas quantity fed to a combustion space by an exhaust gas recirculation system of the engine and an ignition point for combustion, as a function of the signal value which represents a current residual gas fraction.

6. Engine control system according to claim 1, wherein the engine control system monitors proper functioning of an exhaust gas recirculation system of the internal-combustion engine, by means of the signal value which represents a current residual gas fraction.

7. Engine control system according to claim 1, wherein:

as a function of the signal value representing a current residual gas fraction, the engine control system adjusts engine operation when the engine control system determines existence of a steady-state or quasi-steady-state engine operation.

8. The engine control system according to claim 7, wherein:

a function of the signal value which represents a current residual gas fraction, the engine control system adjusts engine operation when the engine control system determines existence of engine operation with an extrastoichiometric air/fuel mass ratio in the carbureted fuel.

9. Engine control system according to claim 8, wherein during rich operation of the engine, the signal value which represents the residual gas fraction has a value calculated according to the equation:

$r_R=\frac{{\mathrm{\Phi <br><br>}}_z-{\mathrm{\Phi <br><br>}}_f}{{\mathrm{\Phi <br><br>}}_z-\frac{1}{\mathrm{\Delta <br><br>}}}$

wherein

r_R=residual gas fraction

φ

_z=air/fuel mass ratio in the exhaust gas

φ

_f=air/fuel mass ratio in the carbureted fuel

Δ

=stoichiometric air/fuel mass ratio.

10. Engine control system according to claim 8, wherein during lean operation of the engine, the signal value which represents a residual gas fraction has a value calculated according to the equation:

$r_R=\frac{1-\frac{{\mathrm{\Phi <br><br>}}_z}{{\mathrm{\Phi <br><br>}}_f}}{1-{\mathrm{\Phi <br><br>}}_z·<br><br>\mathrm{\Delta <br><br>}}$

wherein

r_R=residual gas fraction

φ

_z=air/fuel mass ratio in the exhaust gas

φ

_f=air/fuel mass ratio in the carbureted fuel

Δ

=stoichiometric air/fuel mass ratio.

11. Engine control system according to claim 1, wherein the sensor system has a separate sensor for measuring air/fuel mass ratio separately for each combustion space of the engine.

12. Engine control system according to claim 11, wherein a recirculated exhaust gas quantity is varied by triggering an adjusting valve in an exhaust gas recirculation system as a function of combustion space currently to be filled.

13. A method of controlling operation of an internal combustion engine having a computer, and a memory and a sensor system associated with the computer, said method comprising:

said computer determining existence of a substantially steady state operation of said engine, based on signals from said sensor arrangement; and

during existence of a substantially steady state operation of said engine, based on a signal generated by said computer which represents an actual current air/fuel ratio of a mixture input to a combustion chamber of said engine, and on a signal received from the sensor system representing a current air/fuel ratio of an exhaust gas discharged from said combustion chamber, said computer generating a signal which represents a current exhaust gas mass fraction; and

recirculating and mixing a portion of said exhaust gas with said mixture input to said combustion chamber, as a function of said signal which represents a current exhaust gas mass fraction.

14. An electronic engine control system according to claim 13 wherein said exhaust gas mass fraction is a residual gas fraction.

15. An electronic engine control system for an internal combustion engine having a computer, a plurality of sensors for measuring operating parameters of the engine, and a memory encoded with a program which includes steps for:

said computer determining existence of a substantially steady state operation of said engine, based on signals from said sensor arrangement; and

during existence of a substantially steady state operation of said engine, based on a signal generated by said computer which represents an actual current air/fuel ratio of a mixture input to a combustion chamber of said engine, and on a signal received from the sensor system representing a current air/fuel ratio of an exhaust gas discharged from said combustion chamber, said computer generating a signal which represents a current exhaust gas mass fraction; and

said computer causing a recirculating and mixing a portion of said exhaust gas with said mixture input to said combustion chamber, as a function of said signal which represents a current exhaust gas mass fraction.

16. An electronic engine control system according to claim 15 wherein said exhaust gas mass fraction is a residual gas fraction.

17. A method for controlling operation of an internal combustion engine having a computer, and a memory and a sensor system associated with the computer, said method comprising:

said computer determining a first signal value which represents an actual current air/fuel ratio of a fuel mixture fed to a combustion space of said engine, based on signals from sensors in said sensor system;

said computer receiving a second signal value sensed by said sensor system, which second signal is indicative of a current air/fuel mass ratio of an exhaust gas discharged from the combustion space of the engine after a combustion;

based on said first and second signal values, said computer generating a signal indicative of a current exhaust gas mass fraction which, together with said fuel mixture fed to said combustion space, forms a content of the combustion space prior to a combustion; and

recirculating and mixing a portion of said exhaust gas with said mixture input to said combustion chamber, as a function of said signal which represents a current exhaust gas mass fraction.

18. The method according to claim 17 wherein said exhaust gas mass fraction is a residual gas fraction.