Extension of SwRI's Multidimensional Control Framework to Fueling and Ignition Control of Spark-Ignited Engines, 03-R8438
Inclusive Dates: 01/01/14 – Current
Background — For the past decade or so, SwRI has championed the idea of diesel engine pollution control at source (i.e., in combustion chamber). As a complementary enhancement to this idea, the Institute has pursued over the past six years management of in-cylinder state. This two-pronged approach comprising in-cylinder state-based fueling and active management of in-cylinder state has a solid foundation in physical processes and, generally speaking, extends to all internal combustion engines. SwRI has generated and patented significant intellectual property (IP) in this area, conducted externally and internally funded work, and published results (see internal research project 03-R8179 final report).
Approach — The approach is to apply our control system for the Dedicated Exhaust Gas Recirculation (DEGR) engine demonstrated in internal research project 03-R8329, see Figure 1. While the DEGR engine is relatively simple from a conceptual standpoint (full-time 25-percent EGR), it poses a challenge from a control standpoint because of the additional air handling devices and actuators required. The framework for our control system developed in the previous work should now be extended to the stoichiometric, SI gasoline engine with EGR. What is required to accomplish this is summarized in the following two problem statements:
- In-cylinder state-based fueling for three-way catalyst (TWC) control: The idea of in-cylinder state-based fueling is well grounded in physical principles and has been developed and tested extensively in previously conducted work. The question is whether the idea can be implemented efficiently and uniformly for the lean/rich switching required for TWC control.
- In-cylinder state-based ignition: Control of combustion can be significantly improved by extending the concept of state-based fueling to the control of ignition. The question is how well the concept of determining fueling quantity, timing, pressure, and pattern based on estimated in-cylinder conditions extends to the determination of ignition timing, duration, and pattern.
The overall control schematic is shown below, see Figure 2. This control structure has been used by SwRI extensively in previous work. This program seeks to add to and refine the portion of the schematic noted in red, namely, fueling and ignition control.
Accomplishments — The effort is on-going and has made progress toward the goals of the project. We are currently testing the multi-dimensional calculation developed for timing, duration and ignition pattern control. SwRI's state-based fueling has been extended to include TWC control. Finally, we have successfully extended SwRI's active management of in-cylinder state to a spark-ignited gasoline engine with EGR.