Turbo-discharging turbocharged internal combustion engines

Williams, Andrew M.; Baker, Alan T.; Garner, Colin P.; Vijayakumar, Ramkumar

doi:10.1177/0954407012455986

Cited by 10 publications

(5 citation statements)

References 14 publications

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“…In this study, the focus is to exploit the impact of key engine parameters and boost strategies on the overall engine performance. Therefore, the mapless approach [34,35] was applied in this study to model the turbine and compressor for both supercharger and turbocharger. Specifically, the efficiency of the compressor for both supercharger and turbocharger was set at 0.75 and the efficiency of the turbine was set at 0.7.…”

Section: Engine Simulation Modelsmentioning

confidence: 99%

Analysis of the Boost System for a High Performance 2-Stroke Boosted Uniflow Scavenged Direct Injection Gasoline (BUSDIG) Engine

Wang¹,

Zhao²

2020

SAE Technical Paper Series

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A 2-stroke boosted uniflow scavenged direct injection gasoline (BUSDIG) engine was researched and developed at Brunel University London to achieve higher power-to-mass ratio and thermal efficiency. In the BUSDIG engine concept, the intake scavenge ports are integrated to the cylinder liner and controlled by the movement of piston top while exhaust valves are placed in the cylinder head. Systematic studies on scavenging ports, intake plenum, piston design, valve opening profiles and fuel injection strategies have been performed to investigate and optimise the scavenging performance and in-cylinder fuel/air mixing process for optimised combustion process. In order to achieve superior power performance with higher thermal efficiency, the evaluation and optimisation of the boost system for a 1.0 L 2-cylinder 2-stroke BUSDIG engine were performed in this study using one dimensional (1D) engine simulations. The results show that the engine exhaust valve opening (EVO) timing and exhaust duration (ED) are key parameters affecting the engine performance with the single-stage turbocharging (T). By using an earlier EVO timing of 80 ⁰CA and a longer ED of 140 ⁰CA, a maximum brake power of 130.7 kW could be achieved at 3200 rpm and peak torque output of 488 N*m at 1600 rpm. Simulations were also performed to evaluate the engine performance with combined boost systems with a supercharger upstream the turbocharger (S-T) and a turbocharger upstream the supercharger (T-S). The results indicate that the combined boost systems increase both engine power and torque compared to the single-stage turbocharging system. In particular, the peak brake power and torque of the 1.0 L BUSDIG engine could reach 143.7 kW at 4000 rpm and 492 N*m at 800 rpm with the S-T setup.

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Section: Engine Simulation Modelsmentioning

confidence: 99%

Analysis of the Boost System for a High Performance 2-Stroke Boosted Uniflow Scavenged Direct Injection Gasoline (BUSDIG) Engine

Wang¹,

Zhao²

2020

SAE Technical Paper Series

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“…where p 2 is the pressure at the rotor outlet. Based on this hypothesis, the exhaust flow across the turbine is calculated using the subsonic flow for a restriction with C inserted into equation (1). The expansion ratio produced by the exhaust gas passes Figure 2.…”

Section: Turbine Flow Characteristic Modelmentioning

confidence: 99%

“…Turbocharging technology is an effective way to downsize the engine, to increase the power density and to reduce the emissions. [1][2][3] The problem of plateau adaptability arises when a turbocharged diesel engine operates at a high altitude or at different altitudes. The boost pressure and the air mass flow are reduced owing to the changing ambient conditions with increasing operating altitude, which results in a lower engine power, a higher exhaust temperature and a lower fuel economy.…”

Section: Introductionmentioning

confidence: 99%

Equivalent matching model of a regulated two-stage turbocharging system for the plateau adaptability

Guo-zheng

Zhang

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part D:

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The matching problem becomes much more difficult between a regulated two-stage turbocharging system and a diesel engine when they are required to work at different altitudes. This is mainly because there are three or even four main variables to be determined for a regulated two-stage turbocharging system, and the change in the operating altitude also extends the matching problem from a two-dimensional problem of the speed and the load to a three-dimensional problem of the speed, the load and the operating altitude. An optimal scheme for a regulated two-stage turbocharging system should be determined to optimize the plateau adaptability based on the relationship between the matching point, the desirable pressure ratio distribution and the operating altitude. Therefore, a theoretical study on matching a regulated two-stage turbocharging system to a diesel engine at different altitudes is conducted in this paper. The turbine equivalent area of a regulated two-stage turbocharging system is derived on the basis of the turbine flow characteristic model with the thermodynamics equations and the mass and energy conservation of the turbocharging system. The speed and altitude ranges are discussed with the results calculated by the proposed matching model in MATLAB software. Then the simulations with GT-Power software are carried out to validate the application of the equivalent matching model. The calculated results show that the problem of the speed range of the regulated two-stage turbocharging system at different altitudes can be converted to the speed range of a matching scheme based on different pressure ratio distributions at a constant altitude. The altitude range of the regulated two-stage turbocharging system is mainly affected by the matching speed and the bypass flow rate ratio. The validation results of the GT-Power model show that the plateau adaptability of the matched regulated two-stage turbocharging system can be investigated effectively using the equivalent matching model. Therefore, the equivalent matching model can be utilized to achieve a reasonable selection of the matching speed and it can simplify the matching problem of the regulated two-stage turbocharging system at different altitudes.

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“…At Loughborough University, a novel DEP called turbo discharging (TD) was first investigated by means of both simulations and engine tests. [108][109][110] This concept can be applied to both NA and turbocharged engines. For NA engines (see Figure 11), the blow-down pulse is fed into the turbine, while the scavenging mass flow is directed to the postturbine or the pre-compressor.…”

Section: Exhaust System Optimizationmentioning

confidence: 99%

Novel approaches to improve the gas exchange process of downsized turbocharged spark-ignition engines: A review

Akehurst

Brace

2015

International Journal of Engine Research

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Engine downsizing, which is the use of a smaller engine that provides the power of a larger engine, is now considered a mega-trend for the internal combustion engine market. It is usually achieved using one or more boosting devices including a supercharger or a turbocharger. Although supercharging is beneficial for engine's transient response, turbocharging technology is more widely adopted considering its advantages in fuel efficiency. Compared to turbocharged compression ignition engines, turbocharged spark-ignition engines tend to be more challenging with respect to the gas exchange process mainly due to their higher pumping loss, the need for throttling and the fact that spark-ignition engines demand more controllability due to the mitigation of knock, particularly with regard to minimizing trapped residuals. These challenges encourage the entire gas exchange process of turbocharged spark-ignition engines to be regarded as a complete air management system instead of just looking at the boosting system in isolation. In addition, more research emphasis should be focused on novel approaches to improve the gas exchange process of downsized turbocharged spark-ignition engines because the refinement of the conventional technologies cannot provide continuous gains indefinitely and only innovative concept may improve the engine performance to meet the fuel efficiency target and the more stringent emission regulation in the future. This article will first briefly review knowledge of the current state of the art technologies that are in production as opposed to approaches that are currently only being investigated at a research level. Next, more novel methods of the gas exchange process are introduced to identify the improved synergies between the engine and the boosting machine. The major findings to improve the gas exchange process that emerge from this review comprise four aspects (depending on the location where the novel technologies are implemented) which are as follows: charge air pressurization/de-pressurization improvement, combustion efficiency enhancement within the chamber, valve event-associated development and exhaust system optimization. Although the interaction between these technologies on different aspects of the gas exchange process was found to be highly complex, the optimization or the combination of these technologies is anticipated to further improve a downsized turbocharged spark-ignition engine's performance.

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Turbo-discharging turbocharged internal combustion engines

Cited by 10 publications

References 14 publications

Analysis of the Boost System for a High Performance 2-Stroke Boosted Uniflow Scavenged Direct Injection Gasoline (BUSDIG) Engine

Analysis of the Boost System for a High Performance 2-Stroke Boosted Uniflow Scavenged Direct Injection Gasoline (BUSDIG) Engine

Equivalent matching model of a regulated two-stage turbocharging system for the plateau adaptability

Novel approaches to improve the gas exchange process of downsized turbocharged spark-ignition engines: A review

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