IC-Engine Downsizing and Pressure-Wave Supercharging for Fuel Economy

In conventional vehicles the entire power is derived from the IC engine, so it is obligatory to size the engine larger than necessary for its cruising speed. The engine must be designed to account for peak power requirements like acceleration. This oversizing of the engine shifts the operating point from its efficient zone and this adversely affects the fuel economy and emissions. The idea of hybridization is that a part of the total power required can be replaced by an auxiliary power source, generally a motor powered by batteries. Hence, the IC engine can be designed for average load and can be operated with better fuel efficiency. A simulation tool called ADVISOR (Advanced Vehicular Simulator) is used for this study. The software takes the vehicle input and the drive cycle from the user, simulates the vehicle drive and gives fuel economy, acceleration performance and emissions. In this study, each of the three vehicle platforms (average SUV, full size SUV and heavy truck) is selected and a reasonable power level for that vehicle platform is taken from the data of the current conventional vehicle type. The powertrain is then hybridized by replacing part of the total power by an equivalent motor power and a set of simulations are run in ADVISOR at three different battery charge capacities to understand the effect of on-board charge. A weighted combination of performance and fuel economy results is recorded for each run, and the simulations are then repeated at a higher level of hybridization. The results for a range of “percent hybridization” levels are then evaluated to determine the optimum level. A cost optimization is also done by adding weighted factors based on cost effect of the motor, batteries, and the projected lifetime fuel costs. The penalty due to the weight of the batteries is reflected in the simulated performance and fuel economy of the vehicle, and the space effect of the batteries is also considered. The results of this thesis support the conclusion that parallel hybridization of the drive train could help SUVs and heavy trucks to improve fuel efficiency. Depending on the assumptions made for replacement battery costs and total mileage over the lifetime of the vehicle, the increased initial cost of a hybrid SUV can be justified by the operating cost savings; the benefits of hybridization are even more pronounced for heavy trucks. The “optimum” hybridization percentages are reported for each platform, with and without cost considerations.

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Optimal Hybridization of Conventional ICE Vehicles

Eng ◽

10.3390/eng2040037 ◽

2021 ◽

Vol 2 (4) ◽

pp. 592-607

Author(s):

Zhemin Hu ◽

Ramin Tafazzoli Mehrjardi ◽

Lin Lai ◽

Mehrdad Ehsani

Keyword(s):

Electric Drive ◽

Fuel Economy ◽

Hybrid Electric Vehicle ◽

Passenger Cars ◽

Drive Power ◽

Ic Engine ◽

Vehicle Performance ◽

Electric Drives ◽

Ic Engines ◽

Toyota Prius

Most commercially available hybrid electric vehicle (HEV) drivetrains are made of small internal combustion (IC) engines and large electric drives to improve fuel economy. They usually have higher cost than the conventional IC-engine-based vehicles because of the high costs of the electric drives. This paper proposes a hybridized powertrain composed of the original full-size engine of the vehicle and a universally optimum size parallel electric drive. The dynamic programming (DP) algorithm was used to obtain the sensitivity of the maximum miles per gallon (MPG) values versus the power rating of the electric drive. This sensitivity was then analyzed to determine the optimal window of the electric drive power ratings. This was proven to be universal for all passenger cars of various masses and engine powers. The fuel economy and vehicle performance of this HEV was compared with those of the 2019 Toyota Corolla, a conventional IC-engine-based vehicle, and the 2019 Toyota Prius, a commercially available HEV. The results showed that the proposed universally optimized HEV powertrain achieved better fuel economy and vehicle performance than both the original ICE and HEV vehicles, at low additional vehicle cost.

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Model-order reduction for prediction of pressure wave propagation dynamics in the IC engine air path system

2013 American Control Conference ◽

10.1109/acc.2013.6580647 ◽

2013 ◽

Cited By ~ 1

Author(s):

Stephanie Stockar ◽

Marcello Canova ◽

Yann Guezennec

Keyword(s):

Wave Propagation ◽

Pressure Wave ◽

Model Order Reduction ◽

Order Reduction ◽

Ic Engine ◽

Model Order ◽

Path System ◽

Propagation Dynamics

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Computational Analysis of Flow Dynamics in a Four-Stroke Internal Combustion Engine

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1030-1032.1163 ◽

2014 ◽

Vol 1030-1032 ◽

pp. 1163-1166

Author(s):

Shian Gao ◽

Peter Blunt ◽

Robert Simpson

Keyword(s):

Steady State ◽

Pressure Wave ◽

Combustion Engine ◽

Flow Characteristics ◽

Transient Pressure ◽

Inlet Valve ◽

Ic Engine ◽

Wave Effects ◽

Detailed Simulation ◽

Inlet Manifold

This paper presents a predictive investigation using CFD techniques focusing on the tradeoff between steady-state airflow considerations and unsteady transient pressure wave tuning of a single cylinder IC engine. An axisymmetric CFD model has been developed to initially examine the steady-state flow characteristics generated by different inlet entry radii. This has then been further developed to incorporate the unsteady, transient pressure wave effects caused by the motion of inlet valve and piston. Detailed simulation results, which are validated against experimental data provided by Group Lotus plc, are reported here and quantitative conclusions are drawn for maximising airflow in future inlet manifold design.

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Performance Tuning of an IC Engine Based on Pressure Wave Propagation With a Continuously Variable Exhaust Runner Length and Exhaust Valve Timing System

Volume 6: Energy ◽

10.1115/imece2017-70362 ◽

2017 ◽

Cited By ~ 4

Author(s):

V. Gajula ◽

S. Bari

Keyword(s):

Pressure Wave ◽

Engine Performance ◽

Exhaust Valve ◽

Performance Tuning ◽

Valve Timing ◽

Ic Engine ◽

Scavenging Effect ◽

Varying Length ◽

Valve Opening ◽

Positive Effect

The momentum of exhaust gas flowing out of the valve creates a pressure wave which can have a positive effect on the evacuation of gases. This concept is known as wave tuning, utilizes the sub-atmospheric pressure waves in the runner to evacuate more exhaust gases. When tuned precisely by varying length and/or exhaust valve timing in such a way that the wave returns in accordance to the exhaust valve opening, it creates a scavenging effect and this improves the engine performance. In this research both exhaust runner length and valve duration have been changed to arrive the sub-atmospheric wave at exhaust valve to improve the performance of the engine using Ricardo WAVE software. It was found that varying the exhaust valve timing managed to improve the torque by 1–3% at different rpm. However, varying both length and timing improved the toque 7–10% at lower speed and 3–6% at higher rpm.

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IC Engine Air System Uni-, Bi-, and Tri-Directional Energy Flow Optimisation: Turbocharging, Turbocompounding and Turbodischarging

Volume 2: Fuels; Numerical Simulation; Engine Design, Lubrication, and Applications ◽

10.1115/icef2013-19118 ◽

2013 ◽

Author(s):

Andy M. Williams ◽

Alan T. Baker ◽

Ramkumar Vijayakumar

Keyword(s):

Fuel Consumption ◽

Fuel Economy ◽

Energy Flow ◽

Engine Performance ◽

Lean Burn ◽

Ic Engine ◽

Performance And Emission ◽

Air System ◽

Fuel Consumption Benefit ◽

Consumption Benefit

Air systems are becoming increasingly complex and important for achieving IC engine performance and emission targets. Turbocharging is becoming increasingly prevalent enabling high power density engines, improved pumping work and improved fuel economy. Turbo-compounding allows turbine energy to contribute directly to crankshaft work with the aim of improving fuel economy. Turbodischarging allows turbine energy to be used to extract exhaust gases from the engine reducing pumping work and residual gas fraction while simultaneously increasing the amount of energy that can be recovered by the turbine(s). The optimum energy flow split between turbocharging, turbodischarging and turbocompounding has not previously been explored. This paper presents results of a study investigating the potential of tri-directional energy flow optimisation in comparison to uni-directional optimisation and bi-directional optimisation (i.e. using all three approaches, any two approaches or turbocharging alone). Thermodynamic analysis demonstrates the potential of bi-directional optimisation to achieve realistically 4% fuel consumption benefit for both turbocharging and discharging, and turbocharging and compounding on gasoline engines from pumping work alone. The peak benefit of the former occurs at a slightly lower engine torque than the latter as the energy cost of a unit fuel consumption benefit with turbodischarging increases with increasing levels of exhaust depressurisation. The Tri-directional optimisation shows a complex optimum position utilising all three systems and achieving a realistic peak benefit of 4.4% fuel consumption improvement. Optimisation on diesel engine architectures suggests significantly lower potential in the order of 1% benefit while lean burn gas engines showed up to 2.6% benefit. Sensitivity to compression and expansion efficiencies, exhaust manifold volume and system temperatures are presented. The future hybridisation of IC engine air systems may enable energy storage. This paper offers fundamental insight into the marginal fuel cost of capturing energy from the three systems and the marginal fuel value of using stored energy in the air system.

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Microstructure of an extruded rapidly solidified Al-8Fe-2Mo alloy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144218 ◽

1986 ◽

Vol 44 ◽

pp. 548-549

Author(s):

W. T. Donlon ◽

J. E. Allison ◽

S. Shinozaki

Keyword(s):

Electron Microscopy ◽

Automotive Industry ◽

Fuel Economy ◽

High Strength ◽

Al Alloys ◽

Light Weight ◽

Thin Sections ◽

Strength And Durability ◽

Rapidly Solidified ◽

Whitney Aircraft

Light weight materials which possess high strength and durability are being utilized by the automotive industry to increase fuel economy. Rapidly solidified (RS) Al alloys are currently being extensively studied for this purpose. In this investigation the microstructure of an extruded Al-8Fe-2Mo alloy, produced by Pratt & Whitney Aircraft, Goverment Products Div. was examined in a JE0L 2000FX AEM. Both electropolished thin sections, and extraction replicas were examined to characterize this material. The consolidation procedure for producing this material included a 9:1 extrusion at 340°C followed by a 16:1 extrusion at 400°C, utilizing RS powders which have also been characterized utilizing electron microscopy.

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