Power plants – Fluid motor means driven by waste heat or by exhaust energy... – With supercharging means for engine
Reexamination Certificate
2000-03-31
2001-10-23
Wolfe, Willis R. (Department: 3747)
Power plants
Fluid motor means driven by waste heat or by exhaust energy...
With supercharging means for engine
C060S605200, C123S568120, C123S704000
Reexamination Certificate
active
06305167
ABSTRACT:
TECHNICAL FIELD
1. Background Art
In the control of heavy duty internal combustion engines, the conventional practice utilizes electronic control units having volatile and non-volatile memory, input and output driver circuitry, and a processor that executes instructions to control the engine and its various systems and sub-systems. A particular electronic control unit communicates with numerous sensors, actuators, and other electronic control units to control various functions, which may include various aspects of field delivery, transmission control, and many others.
However, the heavy duty engine business is extremely competitive. Increased demands are being placed on engine manufacturers to design and build engines that provide better engine performance, improved reliability, and greater durability while meeting more stringent emission and noise requirements.
For the foregoing reasons, there is a need for an improved method of controlling an internal combustion engine including an exhaust gas recirculation (EGR) system with improved performance and more precise control than existing systems.
2. Disclosure of Invention
It is, therefore, an object of the present invention to provide a method of controlling an internal combustion engine with improved performance and more precise emission controls than existing systems, with some embodiments including an exhaust gas recirculation (EGR) system.
In carrying out the above object, a method of controlling an internal combustion engine is provided. The engine includes a variable geometry turbocharger (VGT) driven in response to a VGT command signal. The engine further includes a variable flow exhaust recirculation (EGR) system driven in response to an EGR command signal to recirculate exhaust to an engine intake mixture. The method comprises determining the EGR command signal based on at least one engine condition, and determining the VGT command signal based on at least one engine condition and at least partially based on the EGR command signal.
In a preferred embodiment, determining the VGT command signal further comprises determining a lead compensated signal based on the EGR command signal. The VGT command signal is determined at least partially based on the lead compensated signal. Further, preferably, determining the EGR command signal further comprises determining a desired carbon dioxide quantity of the intake mixture. The EGR command signal is then determined based on the desired carbon dioxide quantity. More preferably, determining the EGR command signal further comprises estimating an actual carbon dioxide quantity of the intake mixture. The desired carbon dioxide quantity is compared to the estimated actual carbon dioxide quantity to determine an error signal. The EGR command signal is based on the error signal. Further, in a preferred embodiment, determining the desired carbon dioxide quantity further comprises determining the desired carbon dioxide quantity based in part on an oxygen to fuel ratio of the intake mixture. Even further, in a preferred embodiment, determining the desired carbon dioxide quantity further comprises determining an engine torque demand and determining an engine speed. The desired carbon dioxide quantity is based on the oxygen to fuel ratio of the intake mixture, the torque demand, and the engine speed.
Even further, in a preferred embodiment, determining the EGR command signal further comprises determining the EGR command signal further based on at least one controller gain term. More preferably, the EGR command signal is further based on a gain normalization term.
Further, in carrying out the present invention, a method of controlling a compression-ignition internal combustion engine is provided. The engine includes a variable geometry turbocharger driven in response to a VGT command signal. The engine further includes a variable flow exhaust gas recirculation system driven in response to an EGR command signal to recirculate exhaust to an engine intake mixture. The method comprises determining an engine torque demand, determining an engine speed based at least partially on the driver accelerator demand and the engine speed. The method further comprises determining the EGR signal based at least partially on torque demand and engine speed. The method further comprises determining the VGT command signal based on at least one engine condition and at least partially based on the EGR command signal.
Still further, in carrying out the present invention, a method of controlling an internal combustion engine is provided. The engine includes a variable geometry turbocharger driven in response to a VGT command signal, and a variable flow exhaust gas recirculation system driven in response to an EGR command signal to recirculate exhaust to an engine intake mixture. The method comprises determining the EGR command signal based on at least one engine condition, determining a desired oxygen quantity of the intake mixture, and estimating an actual oxygen quantity of the intake mixture. The method further comprises determining the VGT command signal based on the desired oxygen quantity, the estimated actual oxygen quantity, and the EGR command signal.
In a preferred embodiment, determining the VGT command signal further comprises determining a feedforward term based on at least one engine condition, and determining the VGT command signal further based on the feedforward term. More preferably, the feedforward term is determined based on an engine torque demand and an engine speed.
In a preferred implementation, determining the VGT command signal further comprises determining a lead compensated signal based on the EGR command signal, and determining the VGT command signal based on the desired oxygen quantity, the estimated actual oxygen quantity, the lead compensated signal, and the feedforward term. A preferred method further comprises determining an adjusted oxygen quantity error signal based on the desired oxygen quantity, the estimated actual oxygen quantity, and lead compensated signal. The VGT command signal is determined based on the error signal and the feedforward term. In some implementations, the error signal is modified based on at least one controller gain term. In some embodiments, a gain normalization term is determined and the error signal is modified based on the gain normalization term. Preferably, the gain normalization term is based on a determined engine air intake flow. More preferably, determining the air intake flow further comprises determining an engine torque demand, determining an engine speed, and determining the engine air intake flow based on the torque demand and the engine speed. Most preferably, determining the gain normalization term further comprises determining the gain normalization term such that the term effectively eliminates the error signal for a significantly low air intake flow.
Yet further, in carrying out the present invention, a method of controlling an internal combustion engine is provided. The engine includes a variable flow exhaust gas recirculation system driven in response to an EGR command signal to recirculate exhaust to an engine intake mixture. The method comprises determining a desired engine intake mixture composed of a plurality of different components, estimating an actual engine intake mixture composition, and comparing the desired intake composition to the estimated actual intake composition.
The method further comprises controlling the engine based on the comparison.
In some embodiments, controlling the engine further comprises determining the EGR command signal. In some embodiments, the engine includes a variable geometry turbocharger driven in response to VGT command signal, and controlling the engine further comprises determining the VGT command signal. In a preferred embodiment, the engine includes a variable geometry turbocharger, and controlling the engine further comprises determining the EGR command signal based on the comparison, and determining the VGT command signal based at least partially on the EGR command signal.
Yet further, in carr
Kreso Admir
May Andrew
Weisman, II Steve Miller
Brooks & Kushman P.C.
Detroit Diesel Corporation
Wolfe Willis R.
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