Comparative study of turbocharged diesel engine emissions during three different Transient Cycles

Giakoumis, Evangelos G.; Alafouzos, Alexios I.

doi:10.1002/er.1625

Cited by 13 publications

(7 citation statements)

References 9 publications

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“…An SQP method is able to efficiently solve this sequence of related problems; see Section 3.1.2. [72] are used as test cases. This driving profile prescribes the engine speed and the load torque over time.…”

Section: Engines With and Without Egrmentioning

confidence: 99%

Optimal Control of Diesel Engines: Numerical Methods, Applications, and Experimental Validation

Asprion

Chinellato²,

Guzzella

2014

Mathematical Problems in Engineering

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In response to the increasingly stringent emission regulations and a demand for ever lower fuel consumption, diesel engines have become complex systems. The exploitation of any leftover potential during transient operation is crucial. However, even an experienced calibration engineer cannot conceive all the dynamic cross couplings between the many actuators. Therefore, a highly iterative procedure is required to obtain a single engine calibration, which in turn causes a high demand for test-bench time. Physics-based mathematical models and a dynamic optimisation are the tools to alleviate this dilemma. This paper presents the methods required to implement such an approach. The optimisation-oriented modelling of diesel engines is summarised, and the numerical methods required to solve the corresponding large-scale optimal control problems are presented. The resulting optimal control input trajectories over long driving profiles are shown to provide enough information to allow conclusions to be drawn for causal control strategies. Ways of utilising this data are illustrated, which indicate that a fully automated dynamic calibration of the engine control unit is conceivable. An experimental validation demonstrates the meaningfulness of these results. The measurement results show that the optimisation predicts the reduction of the fuel consumption and the cumulative pollutant emissions with a relative error of around 10% on highly transient driving cycles.

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Section: Engines With and Without Egrmentioning

confidence: 99%

Optimal Control of Diesel Engines: Numerical Methods, Applications, and Experimental Validation

Asprion

Chinellato²,

Guzzella

2014

Mathematical Problems in Engineering

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“…The lag between increased fueling and the response of the air-charging system discussed previously influences decisively (increases) the NOx concentration too as demonstrated in Figure 1 (Black et al, 2007;Giakoumis and Alafouzos, 2010). Since the main parameter affecting NO (and NOx) formation is the burned gas temperature, locally high temperatures due to close to stoichiometric air-fuel mixtures (formed because of the still low air-supply) are expected to increase NO during the turbocharger lag cycles in Figure 1.…”

Section: Fundamental Aspects Of Diesel Engine Transient Operationmentioning

confidence: 86%

Review of Some Methods for Improving Transient Response in Automotive Diesel Engines through Various Turbocharging Configurations

Giakoumis

2016

Front. Mech. Eng.

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Turbocharged diesel engines suffer from worse transient performance than their naturally aspirated counterparts, mostly at low loads and speeds. This leads to overshoot in engine-out exhaust emissions (primarily particulate matter/soot and NOx) after a speed or load increase, as well as poor drivability. The main cause for this problematic behavior is located in the turbocharger in the form of high moment of inertia and unfavorable aerodynamic-type compressor flow characteristics. In the present work, various alternative turbocharging configurations are reviewed that have proven successful in improving the dynamic diesel engine operation. These configurations are combined supercharging, variable-geometry turbine, electrically assisted turbocharging, two-stage series and sequential turbocharging, and lower turbine moment of inertia. Significant improvement in the engine's transient response can be realized when designing for smaller turbocharger frames or applying more than one units (in series or parallel arrangement). Increasing the available turbine torque (e.g., through elevated turbine back pressure in a variable-geometry turbine) is another successful option, as well as enhancement of the boost pressure (e.g., through the use of a positive displacement compressor upstream of the turbocharger). Finally, the use of external energy (e.g., in the form of electrical assistance on the turbocharger shaft during the critical turbocharger-lag phase) is another recently developed and highly promising measure to mitigate the drawbacks of the poor transient performance of turbocharged diesel-engined vehicles and limit their exhaust emissions. The choice of the "best" configuration for a specific application depends on many parameters, such as cost, matching procedure, control system, and mainly type of engine and drive cycle of the vehicle.

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“…A segment of the World-Harmonized Transient Cycle (WHTC) is used as the driving cycle [19]. This profile prescribes the engine speed and the load torque over time.…”

Section: B Driving Cyclementioning

confidence: 99%

From static to dynamic optimisation of Diesel-engine control

Aspriona

Chinellato²,

Onder

et al. 2013

52nd IEEE Conference on Decision and Control

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A framework for the numerical solution of optimal control problems is modified such that an arbitrary subset of the state variables can be treated as quasi-stationary quantities. This framework is used to reduce the number of state variables of a turbocharged Diesel engine by sequentially omitting the pressure dynamics, the turbocharger inertia, and the thermal dynamics. By comparison to a dynamic simulation using the resulting optimal control inputs, the effects of neglecting these dynamics are assessed. A physics-based combustion model is used in combination with an extended mean-value model for the air path, and a segment of 295s of the World-Harmonized Transient Cycle is considered. The methodology bridges the gap between stationary engine calibration and dynamic optimisation. It reveals which control signals can be represented by lookup maps. For the remaining dynamic control paths, optimal feedforward maps are obtained. Furthermore, the results indicate suitable feedback variables and provide optimal reference maps.

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Comparative study of turbocharged diesel engine emissions during three different Transient Cycles

Cited by 13 publications

References 9 publications

Optimal Control of Diesel Engines: Numerical Methods, Applications, and Experimental Validation

Optimal Control of Diesel Engines: Numerical Methods, Applications, and Experimental Validation

Review of Some Methods for Improving Transient Response in Automotive Diesel Engines through Various Turbocharging Configurations

From static to dynamic optimisation of Diesel-engine control

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