Experimental Investigation of Transient Response and Turbocharger Coupling for High and Low Pressure EGR Systems

Heuwetter, David; Glewen, William; Foster, David E.; Krieger, Roger; Andrie, Michael

doi:10.4271/2014-01-1367

Cited by 6 publications

(3 citation statements)

References 13 publications

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“…The tendency of the new homologation cycles, such as the Worldwide harmonized Light vehicles Test Cycles (WLTC) and Real Driving Emissions (RDE) cycles, will be more restrictive with transient operation which are more pollutant. For that reason, in parallel with the new homologation cycles, it is necessary to improve the control of emissions in transient operations [15]. Experimental and modeling tools were employed to fulfil this study.…”

Section: Introductionmentioning

confidence: 99%

Analysis of low-pressure exhaust gases recirculation transport and control in transient operation of automotive diesel engines

Luján

Climent

Arnau

et al. 2018

Applied Thermal Engineering

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The objective of the study is to determine the behavior of the low pressure exhaust gas recirculation (LP EGR) transport phenomena in the intake manifold during engine transient operation. The investigation also analyzes the influence of the propagation of the pressure waves in the intake manifold on the engine performance. In this sense, there is a clear trade-off: long intake lines improve the engine volumetric efficiency at low engine speeds but delay the EGR transport in the system. The experiments were performed on a test bench with a 1.6 liter Euro-5 specification diesel engine. A CO2 fast tracking measurement device was setup and placed in two locations in the intake line in order to track the EGR transport in transient operation. The CO2 concentration is acquired with crank-angle resolution. Three different engine transients at constant engine speed were studied. They are extreme and worst-case scenarios in driving situations: (i) from low load to full load, (ii) from full load to low load, and (iii) from low load to medium load. In this way, it is possible to observe the behavior of the engine when: (i) leaving the EGR zone, (ii) entering into the EGR zone, and (iii) changing operating point without leaving the EGR zone. A consistent methodology that combines experimental results and a 1D model capable to predict the behavior of the engine was developed. The results obtained in this investigation show a relevant phenomenon: depending on the synchronization of the EGR and Exhaust Throttle (ET) valves, an overshoot occurs when the engine enters into EGR zone. In this study, the results show the importance of the synchronization of the valves that control the EGR strategy. Comparisons between measured and modeled CO2 concentrations lead to conclude that the EGR transport during engine transient operation is correctly predicted within a 1D engine code.

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Section: Introductionmentioning

confidence: 99%

Analysis of low-pressure exhaust gases recirculation transport and control in transient operation of automotive diesel engines

Luján

Climent

Arnau

et al. 2018

Applied Thermal Engineering

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“…14 Moreover, with the EGR valves open, any fluctuations in the VGT rack position would also lead to fluctuations in the EGR mass flow, which eventually degrade the emissions and driveability. 15 In recent years, model predictive control (MPC) has gained the attention of researchers because of its capability in dealing with coupled nonlinear systems. 16,17 It transforms the control problem into an optimization problem and provides precise control of the manipulated objects while complying with the constraints of the manipulated variables.…”

Section: Introductionmentioning

confidence: 99%

Tuneable model predictive control of a turbocharged diesel engine with dual loop exhaust gas recirculation

Zhang

2017

Proceedings of the Institution of Mechanical Engineers, Part D:

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The air path of a turbocharged diesel engine is a multi-input multi-output (MIMO) system with strong nonlinearity, coupling effect, delay and actuator constraints. This makes the design and tuning of the controller complex. In this paper, a tuneable model predictive control (TMPC) controller for a diesel engine's air path with dual loop exhaust gas recirculation (DLEGR) is presented. The objective is to regulate the intake manifold pressure and exhaust gas recirculation (EGR) mass flow in each loop to meet the time-varying setpoints through coordinated control of the variable geometry turbocharger (VGT) and EGR valves. The TMPC controller adopts the design framework of an MPC controller. This controller is also able to provide a map-based switching scheme for the local controller and the controller's weightings. A comparison between the TMPC controller and a conventional PID controller is conducted on a validated real-time engine model. The simulation results show that the TMPC controller achieves lower overshoot, faster response and a shorter settling time on the manipulated objects. These improvements are beneficial for obtaining lower fuel consumption. In order to test the capability of the TMPC controller, it is validated on a hardware in the loop (HIL) platform. The results show that the agreement between the simulation and the actual ECU's response is good.

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“…Heuwetter et al 16,17 combined LR and SR EGR systems on a General Motors Z19DTH 1.9l Euro 4 specification diesel engine equipped with a variable geometry turbine (VGT) to achieve low emissions and fuel consumption without sacrificing transient response capability due to the long EGR path. The authors concluded that hybrid EGR resulted in reductions in almost all recorded emissions for both steady state and transient operation.…”

Section: Introductionmentioning

confidence: 99%

The benefits of a mid-route exhaust gas recirculation system for two-stage boosted engines

Dimitriou

Turner

Burke

et al. 2017

International Journal of Engine Research

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Exhaust Gas Recirculation (EGR) is a widely-known technique applied in internal combustion engines for controlling the combustion process and harmful emissions. The recirculation of gases can be achieved either by delivering burnt gases from upstream of the turbine to downstream of the compressor (short-route) or by taking the exhaust gas downstream the turbine and deliver upstream the compressor (long-route). Although longroute (LR) system is preferred for highly boosted engines due to the higher EGR availability at low engine speeds, it lacks a fast response time during transient performance compared to the short-route (SR) system. This paper examines the potentials of introducing an alternative EGR route which can be applied in two-stage boosted engines. The proposed Mid-Route (MR) EGR system, applied in a gasoline engine, combines the benefits of the LR and SR routes. The system provides high EGR rates at all engine speeds while the transport delay in the case of transient operation is relatively short. The potential of a hybrid EGR system combining MR and LR EGR is examined and various components' (i.e. compressor, turbine and coolers) sizing and transient performance studies are performed to understand the trade-offs of the system. It was demonstrated that MR could provide high EGR particularly at high and low engine speeds. A combination of MR and LR EGR can provide maximum EGR rates at all speeds with a maximum fuel consumption penalty of 1.4% at engine speeds below 2,500rpm. The reduction in EGR response time was of the magnitude of 50% while the faster EGR purging time combined with the smaller turbine implemented, dropped the load tip-in response time by 25%. The coolers' sizing study revealed that an LR EGR cooler is unnecessary whereas the MR EGR cooler can also be omitted when the flow is delivered prior an intercooler with a 25% larger cooling capacity than of the baseline engine.

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Experimental Investigation of Transient Response and Turbocharger Coupling for High and Low Pressure EGR Systems

Cited by 6 publications

References 13 publications

Analysis of low-pressure exhaust gases recirculation transport and control in transient operation of automotive diesel engines

Analysis of low-pressure exhaust gases recirculation transport and control in transient operation of automotive diesel engines

Tuneable model predictive control of a turbocharged diesel engine with dual loop exhaust gas recirculation

The benefits of a mid-route exhaust gas recirculation system for two-stage boosted engines

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