Extreme engine downsizing

Carey, C.; McAllister, Matthew P.; Sandford, Malcolm H.; Richardson, Steve; Pierson, Steven; Darnton, N. J.; Bredda, Scott; Akehurst, Sam; Brace, Chris; Turner, J. W. G.; Pearson, Richard; Luard, N.; Martinez-Botas, Ricardo; Copeland, Colin; Lewis, Michjael James; Fernandes, Josevaldo

doi:10.1533/9780857095879.4.161

Cited by 24 publications

(18 citation statements)

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“…The point is then given a time weighting based on the total driving-cycle time. 107 The calculated fuel economy using the engine steady-state look-up tables has been proved to be within 3% error of running the full vehicle but with approximately 40 times less computational time. 66 2.…”

Section: Modelling Methodologiesmentioning

confidence: 88%

Observations on and potential trends for mechanically supercharging a downsized passenger car engine:a review

Turner

Akehurst

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part D:

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Engine downsizing is a proven approach for achieving a superior fuel efficiency. It is conventionally achieved by reducing the swept volume of the engine and by employing some means of increasing the specific output to achieve the desired installed engine power, usually in the form of an exhaust-driven turbocharger. However, because of the perceptible time needed for the turbocharger system to generate the required boost pressure, a characteristic of turbocharged engines is their degraded driveability in comparison with those of their naturally aspirated counterparts. Mechanical supercharging refers to the technology that compresses the intake air using the energy taken directly from the engine crankshaft. It is anticipated that engine downsizing which is realised either solely by a supercharger or by a combination of a supercharger and a turbocharger will enhance a vehicle's driveability without significantly compromising the fuel consumption at an engine level compared with the downsizing by turbocharging. The capability of the supercharger system to eliminate the high exhaust back pressure, to reduce the pulsation interference and to mitigate the surge issue of a turbocharged engine in a compound-charging system offsets some of the fuel consumption penalty incurred in driving the supercharger. This, combined with an optimised down-speeding strategy, can further improve the fuel efficiency performance of a downsized engine while still enhancing its driveability and performance at a vehicle level. This paper first reviews the fundamentals and the types of supercharger that are currently used, or have been used, in passenger car engines. Next, the relationships between the downsizing, the driveability and the down-speeding are introduced to identify the improved synergies between the engine and the boosting machine. Then, mass production and prototype downsized supercharged passenger car engines are briefly described, followed by a detailed review of the current stateof-the-art supercharging technologies that are in production as opposed to the approaches that are currently only being investigated at a research level. Finally, the trends for mechanically supercharging a passenger car engine are discussed, with the aim of identifying potential development directions for the future. Enhancement of the low-end torque, improvement in the transient driveability and reduction in low-load parasitic losses are the three main development directions for a supercharger system, among which the adoption of a continuously variable transmission to decouple the supercharger speed from the engine speed, improvement of the compressor isentropic and volumetric efficiency and innovation of the supercharger mechanism seem to be the potential trend for mechanically supercharging a passenger car engine.

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Section: Modelling Methodologiesmentioning

confidence: 88%

Observations on and potential trends for mechanically supercharging a downsized passenger car engine:a review

Turner

Akehurst

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part D:

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“…Downsizing strategies have been adopted to produce smaller and lighter engines capable of achieving the performance of much larger ones. To do so, turbochargers are used to recover the lost power due to downsizing and, at the same time, reducing both engine pumping work and friction [131,132]. The downsizing effectiveness was demonstrated by [133], in which a 1.4-L ethanol engine was able to replace gasoline engines as big as 2.4 L and 3.0 L, keeping the original performance and improving fuel consumption.…”

Section: Recent Advances and Trends In Internal Combustion Enginesmentioning

confidence: 99%

The misleading total replacement of internal combustion engines by electric motors and a study of the Brazilian ethanol importance for the sustainable future of mobility: a review

Malaquias

Netto

Filho

et al. 2019

J Braz. Soc. Mech. Sci. Eng.

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The sustainable future of mobility should not be viewed as the burial of the internal combustion engine (ICE), nowadays the main source of vehicular propulsion. Even with the increasing electrification of the transport means, the low global percentage of the electric fleet, around 0.2% of the total road vehicles, associated with an annual growth rate of less than 60%, indicates that they will not significantly change the market share in the short-and medium-term periods. This means that fuel demanded by ICEs and pollutant emissions generated by them will be very relevant in the years to come. Thus, the search for significant advances in technology associated with the use of renewable fuels is very important for environmental and economic sustainability. In this regard, the present work intends to demonstrate that the association between Brazilian ethanol and advanced technology in ICEs is a promising alternative for a more sustainable global mobility in the future. For this purpose, some ethanol properties are presented to justify its relevance as an ideal biofuel for highly boosted and efficient engines. Then, environmental, social, ethical and economic impacts arising from electric vehicles are investigated, demystifying the zero-emission vehicle terminology attributed to them and, finally, new technologies for ICEs are presented, proving that they are constantly evolving and improving, which is fundamental to the future of the world automotive fleet.

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“…Combustion effects such as knock and autoignition were ignored throughout since the operating points selected had been demonstrated experimentally to be achievable. The air-to-fuel ratio (AFR) control in the model was implemented by using direct injection only, the injectors being of an AFR-targeting type, set to achieve stoichiometry at all operating conditions, in accordance with the project target (defined by Carey et al 4 ). The primary load control mechanisms of the engine were thus as follows: the throttle valve; engagement of the supercharger, and its drive ratio; the turbocharger wastegate; the supercharger bypass valve; the inlet and exhaust valve timings; the EGR circuit valve.…”

Section: System Modelmentioning

confidence: 99%

“…As a starting point for the investigation, Minimap point 3 (1500 r/min; 104 N m (according to the work of Carey et al 4 ), equating to a brake mean effective pressure (BMEP) of 6.58 bar for the downsized engine) was chosen owing to its high NEDC weighting value (as defined above) and reasonable load requirement; it is highly unlikely that the supercharger would need to be engaged at loads lower than this. In order to find the optimal settings for the aforementioned load control mechanisms (valve timing, wastegate, etc.…”

Section: Design-of-experiments Parameter Optimisationmentioning

confidence: 99%

“…For ease of analysis and comparison, the performance of the baseline V8 engine (as mounted in the target vehicle) over the NEDC has been discretised into a number of steady-state 'Minimap' operating points, as described by Carey et al 4 Each of these points represents a portion of the driving cycle and holds a weighting equivalent to the proportion of time that the engine is run at this speed and load during the NEDC. Using this method, improvements in the fuel economy over the driving cycle can be estimated much more quickly.…”

Section: Introductionmentioning

confidence: 99%

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Investigation into the trade-off between the part-load fuel efficiency and the transient response for a highly boosted downsized gasoline engine with a supercharger driven through a continuously variable transmission

Rose

Akehurst

Brace

2013

Proceedings of the Institution of Mechanical Engineers, Part D:

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Downsizing is an established trend in the development of passenger car engines. However, the benefits of an improved fuel economy are often obtained at the expense of the engine's dynamic response (owing to increasing demands on the boosting system) and, consequently, the vehicle driveability. The use of a continuously variable transmission in the supercharger driveline offers increased control flexibility over the air path, which could allow more suitable calibrations to be developed. This paper gives details of a co-simulation-based investigation into the trade-off between the steady-state part-load fuel efficiency and the resulting tip-in transient response for a highly boosted downsized gasoline engine. The engine was a 2.0 l in-line four-cylinder unit, designed to replace a 5.0 l, naturally aspirated V8, equipped with a positivedisplacement supercharger in a sequential series arrangement with a fixed-geometry turbocharger with an external wastegate. The supercharger can be de-clutched and bypassed, and therefore three separate supercharger engagement regimes were investigated for part-load operation, defined as follows: with the supercharger disengaged and bypassed; with the supercharger engaged with a fixed drive ratio; with the supercharger engaged using a variable ratio (i.e. through a continuously variable transmission). For each of these supercharger engagement regimes, design-of-experiments and optimisation techniques were used to find the best settings for the key engine control parameters such as the intake and exhaust valve timings and the exhaust gas recirculation rate. Using these calibrations as a starting point, the transient performance was then assessed in fixed-speed tip-in simulations. The trade-off situation was found to be highly complex; identifying the best overall balance of the steady-state efficiency and the dynamic performance requires a subjective assessment. However, the continuously variable transmission does provide the best potential for dynamic response combined with a satisfactory fuel economy. It is suggested that the most suitable solution would be to have multiple userselectable calibrations, such as the 'economy' and 'sport' modes used on many modern vehicles.

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Extreme engine downsizing

Cited by 24 publications

References 0 publications

Observations on and potential trends for mechanically supercharging a downsized passenger car engine:a review

Observations on and potential trends for mechanically supercharging a downsized passenger car engine:a review

The misleading total replacement of internal combustion engines by electric motors and a study of the Brazilian ethanol importance for the sustainable future of mobility: a review

Investigation into the trade-off between the part-load fuel efficiency and the transient response for a highly boosted downsized gasoline engine with a supercharger driven through a continuously variable transmission

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