Transient performance of the mixed flow and radial flow variable geometry turbines for an automotive turbocharger

Kannan, Ramesh; Prasad, B. V. S. S. S.; Sridhara, K

doi:10.1177/0954406220916493

Cited by 3 publications

(3 citation statements)

References 16 publications

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“…This cost-effective solution typically uses an external actuator augmented on an otherwise traditional turbocharger to pivot the angle of vanes surrounding the turbine blades (pivot vane) that capture energy from the flow of exhaust gases or a moving-wall. 10 An aggressive vane angle allows the turbine to capture more energy at low speed and load conditions, where a conventional fixed geometry turbocharger typically suffers. At high speed and load conditions the vane angle can be made much less aggressive, which improves efficiency of the turbocharger.…”

Section: Introductionmentioning

confidence: 99%

Dual-output PID transient control of an electric-assisted air charge system

Gamache

Nieuwstadt

Martz

et al. 2023

International Journal of Engine Research

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Turbo-compressor assembly (also called turbocharger) is added to diesel engines to increase their power density and improve performance. However, during power step-up operations, the added turbocharger system could lead to a significant delay of engine response (also called turbo-lag) which negatively impact drivability. In this paper, an external electric compressor (eBoost) is added to a turbocharged, large displacement diesel engine to significantly reduce turbo-lag, along with a bypass valve. Now, the air charge system has two control targets (boost (intake manifold) pressure and rate of exhaust-gas recirculation (EGR)) but with four control actuators including EGR valve, variable geometry turbo (VGT) vane position, eBoost speed and bypass valve, making it challenge for developing the associated control scheme. In this paper, a dual-output PID (proportional-integral-derivative) controller is proposed for controlling the boost pressure using the VGT and eBoost to reduce turbo-lag, and a transition logic is also devised to detect transient operating conditions to activate the eBoost, along with the closing and opening of the bypass valve, with maximum benefit. The EGR rate PID control remains unchanged. The addition of the eBoost is shown to improve transient response time by up to 55% and reduce transient NOx emissions by up to 42% during transitional operations without negatively impacting steady-state engine performance or emissions. Note that transient performance can be further improved for production implementation when a single engine control module is used by eliminating communication delay among multiple control systems.

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Section: Introductionmentioning

confidence: 99%

Dual-output PID transient control of an electric-assisted air charge system

Gamache

Nieuwstadt

Martz

et al. 2023

International Journal of Engine Research

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“…While the indirect method takes the turbocharger as a subpart of the ICE, the transient performance of the turbocharger is evaluated by analyzing the crankshaft speed, power, torque, and other parameters of the ICE in the engine bench test. 14 It is called the direct method on the transient response of the turbocharged engines. The typical transient process is studied by numerical simulation or bench test, and transient performance is evaluated by engine power, fuel consumption, emissions, or other indicators.…”

Section: Introductionmentioning

confidence: 99%

An evaluation method for transient response performance of a turbocharger in gasoline engine: Simulation and experiment

Wang

2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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The vital issue of response lag and soot emission during transient operation of turbocharged engine, has been studied so far mainly on experiment in engine system rather than turbocharger basis. The study of turbocharger transient performance, however, is extremely important to manufacturers due to the stringent regulations of exhaust emission and economy for the turbocharger engine. Therefore, a general method independent of the engine for evaluating the transient response performance of a gasoline turbocharger is proposed in this paper. First, an explicit relationship between key thermodynamic parameters of turbine and compressor and the evaluation index of [Formula: see text] that can characterize turbocharger transient response are established. Secondly, the proposed evaluation method is tested and verified using the coupling between GT-Power and MATLAB Simulink software based on the gasoline turbocharger. The simulation results show that the appropriate conditions should be selected for the transient response test, including the starting and ending speed, the starting mass flow rate, etc. For this proposed turbocharger, the value of [Formula: see text] has a good consistency when the ending speed is 200,000 r/min and the initial mass flow rate is in the range of 0.0715∼0.0756 kg/s. Moreover, the influence of rotor moment of inertia, turbine efficiency and compressor efficiency on [Formula: see text] is analyzed in this selected condition. Finally, the evaluating method of the transient response performance of the turbocharger is conducted on a test bench. The test results are in good agreement with the simulation results, indicating that the proposed evaluation method for transient response of turbocharger has a good predictability and can be used for quantitative evaluation of transient response-ability for different turbochargers independent of engine.

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“…Their results showed an improvement by 3.66% and 2.18% of the cycle-averaged power and mass flow rate respectively. Later, Kannan et al 17 carried out an experimental study for comparing the transient response between radial and mixed flow turbines equipped with nozzle vanes. They showed that the transient response of the radial turbine makes a delay by about 0.09 s compared to the mixed flow turbine.…”

Section: Introductionmentioning

confidence: 99%

Analysis of performance and time lag of turbocharger turbines fed with gasoline and diesel burnt gases and air under pulsating flow conditions

Ketata

Driss

2022

International Journal of Engine Research

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The turbine, an enabling component of turbochargers, is a seat of highly complex unsteady flow as well as varying gas compositions between diesel and gasoline engines. Thus, it is necessary to take into account different physical models when simulating such turbines. Researchers have often considered the turbine working gas as air, which may not lead to an accurate prediction of actual turbine characteristics. In the present work, the effect of the working gas on the performance of turbocharger turbines as well as on the turbo lag was investigated through a set of numerical simulations for six wastegate opening degrees from 0% up to 100% and under a wide range of the flow pulse frequency ranging from 33.33 up to 166.66 Hz. Four working fluids were involved in this study which are the gasoline burnt gas, diesel burnt gas, air with like gasoline engine waves, and air with like diesel engine waves. The performance of the turbine and its responsiveness quantified as the time lag with burnt gases from both diesel and gasoline engines were compared to those with air. Results showed totally deviated unsteady performance characteristics compared to the turbine working with air. Results also confirmed that considering the working fluid as air may not lead to a fair representation of the actual turbine performance characteristics. The findings of this work put emphasis on the importance of the gas composition when modeling such turbines by engineers especially during the design process where a good turbocharger-engine match has to be met.

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Transient performance of the mixed flow and radial flow variable geometry turbines for an automotive turbocharger

Cited by 3 publications

References 16 publications

Dual-output PID transient control of an electric-assisted air charge system

Dual-output PID transient control of an electric-assisted air charge system

An evaluation method for transient response performance of a turbocharger in gasoline engine: Simulation and experiment

Analysis of performance and time lag of turbocharger turbines fed with gasoline and diesel burnt gases and air under pulsating flow conditions

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