Abstract-Many fuel systems for diesel engines are developed with the help of commercial one-dimensional computational fluid dynamics (1D CFD) solvers that model and simulate the behavior of fluid flow through the interconnected pipes off-line. This paper presents a novel framework to evaluate 1D CFD models in real time on an FPGA. This improves fuel pressure estimation and closes the loop on fuel delivery, allowing for a cleaner and more efficient engine. The real-time requirements of the models are defined by the physics and geometry of the problem being solved. In this framework, the interconnected pipes are partitioned into individual sub-volumes that compute their pressure and flow rate every time step based upon neighboring values. We use timingbased synchronization and multiple Precision Timed (PRET) processor cores to ensure the real-time constraints are met. Leveraging the programmability of FPGAs, we use a configurable heterogeneous architecture to save hardware resources. Several examples are presented along with the implementation results after place and route for a Xilinx Virtex 6 FPGA. The results demonstrate the resource savings and scalability of our framework, confirming the feasibility of our approach -solving 1D CFD models in real time on FPGAs.

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This paper reviews next-cycle and same-cycle control techniques developed by Drivven and implemented at Argonne National Laboratory on a General Motors 1.9L common rail diesel engine. Next-cycle control involves measuring cylinder pressure engine-synchronously, performing calculations, and using the complete result in the control algorithm for the fueling event in the next engine cycle. For this control method, injection timing was manipulated to maintain a specified 50% burn location and was investigated in both single-cylinder and multi-cylinder modes. The engine was tested in steady state with step changes in input parameters such as EGR rate. Similar to next-cycle control, same-cycle control involves measuring cylinder pressure engine-synchronously, performing calculations, and making fueling decisions based on partial results within the same engine cycle. For this control method, injection pulse spacing was manipulated to optimize secondary injections by a heat-release calculated angle-by-angle. Next-cycle and same-cycle control both have the capability of enhancing production engine control while next-cycle control also has great benefits as a calibration aid.

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