The Potential of a Separated Electric Compound Spark-Ignition Engine for Hybrid Vehicle Application

Pipitone, Emiliano; Caltabellotta, Salvatore

doi:10.1115/1.4053393

Cited by 6 publications

(16 citation statements)

References 18 publications

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“…At present, the IC engines have the highest efficiency of 45~50%, with the peak power density and energy density between 1000~1500 W/kg and 1320~5000 W•h/kg [11]. Other disadvantages include the complex transmission system, which generates a lot of noise during the normal operation process [12].…”

Section: Introductionmentioning

confidence: 99%

A Case Study Using Hydrogen Fuel Cell as Range Extender for Lithium Battery Electric Vehicle

Zhi,

Pang,

Wang

et al. 2024

Energies

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This paper presents a case study of a lithium battery and fuel cell integrated powertrain system for a renewable energy vehicle. The performance analysis includes evaluating the energy consumption of the vehicle and the efficiency of the power generation components. When driven solely by the lithium battery at average speeds of 15 km/h and 20 km/h, it was observed that speed significantly influences the travel distance of the vehicle, with higher speeds resulting in lower mileage. The energy efficiency rates were found to be 89.3% and 85.7% at speeds of 15 km/h and 20 km/h, respectively, indicating an 18.1% decrease in efficiency from low to higher speeds. When the lithium battery is solely charged by the hydrogen fuel cell, the efficiency under test conditions reaches approximately 32.5%. In the “FC + B + SC” driving mode, which combines the use of the lithium battery, fuel cell, and solar panel to power the vehicle, the travel range can be extended to 50.62 km and 42.05 km, respectively, representing an increase of over 50%, with overall efficiencies of 63.8% and 60.7%, respectively. This hybrid powertrain system exhibits rapid dynamic response, high energy and power density, and enables longer travel distances for the renewable energy vehicle.

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Section: Introductionmentioning

confidence: 99%

A Case Study Using Hydrogen Fuel Cell as Range Extender for Lithium Battery Electric Vehicle

Zhi,

Pang,

Wang

et al. 2024

Energies

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“…These values are higher than the efficiency of turbines commonly used for turbocharging, on account of the more favorable working condition already mentioned, which allows a design strategy for the best efficiency under steady operation, and also permits the electric generator to control the turbine speed of rotation, maximizing its efficiency, apart from the power produced. Some preliminary evaluations made by the same authors [2][3][4] showed that the separated electric compound engine has good potential, since vehicle fuel economy increments up to 15% may be obtained in comparison to a reference hybrid propulsion system endowed with a traditional turbocharged engine with equal maximum output power (73.5 kW). It was also found that the turbo-generator could contribute to vehicle traction by about 34% of the overall power generated for the propulsion, with a maximum delivered power of about 20 kW.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Propulsion Efficiency Increment through Exhaust Energy Recovery—Part 2: Numerical Simulation Results

et al. 2023

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The efficiency of hybrid electric vehicles may be substantially increased if the energy of exhaust gases, which do not complete the expansion inside the cylinder of the internal combustion engine, is efficiently recovered using a properly designed turbo-generator and employed for vehicle propulsion. Previous studies, carried out by the same authors of this work, showed a potential hybrid vehicle fuel efficiency increment up to 15% employing a 20 kW turbine on a 100 HP-rated power thermal unit. The innovative thermal unit proposed here is composed of a supercharged engine endowed with a properly designed turbo-generator, which comprises two fundamental elements: an exhaust gas turbine expressly designed and optimized for the application, and a suitable electric generator necessary to convert the recovered energy into electric energy, which can be stored in the on-board energy storage system of the vehicle. In this two-part work, the realistic efficiency of the innovative thermal unit for hybrid vehicles is evaluated and compared to a traditional turbocharged engine. In Part 1, the authors presented a model for the prediction of the efficiency of a dedicated radial turbine, based on a simple but effective mean-line approach; the same paper also reports a design algorithm, which, thanks to some assumptions and approximations, allows fast determination of the right turbine geometry for a given design operating condition. It is worth pointing out that, being optimized for quasi-steady power production, the exhaust gas turbine here considered is quite different from the ones commonly employed for turbocharging applications; for this reason, and in consideration of the required power size, such a turbine is not available on the market, nor has its development been previously carried out in the scientific literature. In this paper, Part 2, a radial turbine geometry is defined for the thermal unit previously calculated, employing the design algorithm described in Part 1; the realistic energetic advantages that could be achieved by the implementation of the turbo-generator on a hybrid propulsion system are evaluated through the performance prediction model under different operating conditions of the thermal unit. As an overall result, it was estimated that, compared to a reference traditional turbocharged engine, the turbo-compound system could gain vehicle efficiency improvement between 3.1% and 17.9%, according to the output power delivered, with an average efficiency increment of 10.9% evaluated on the whole operating range.

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“…Moreover, since the rotational speed of the turbine is independent from the engine and from the compressor, it can be optimally controlled and set to the best value acting through the connected generator. In their preliminary studies [13,14], the authors demonstrated that this system is very promising, as it may achieve overall vehicle efficiency advantages up to 15% with respect to a reference hybrid propulsion system of the same nominal overall output power (73.5 kW) equipped with a traditional turbocharged engine. Furthermore, the authors showed that the contribution of the turbogenerator may reach an impressive 33.9% share of the total power generated by the whole system, with maximum power delivered of 20 kW; in this regard, it must be pointed out that in their previous works, the exhaust gas turbine considered was supposed to be optimized for steady-state operation, since in a hybrid propulsion system the thermal engine undergoes small speed and load variations.…”

Section: Introductionmentioning

confidence: 99%

“…These values are substantially higher than the efficiency of a common turbocharging turbine on account of the more favourable working condition already mentioned, which allows a design strategy aimed at maximizing the efficiency in steady operation, and also permits the control module of the electric generator to operate the turbine at its best efficiency speed ratio, regardless of the power produced. It is also worth noting that in the preliminary evaluations performed [13,14], the efficiency of the electric motor (0.90) employed to drive the supercharger was considered in the evaluation of the power drained by the compressor, since it constitutes an ancillary device, which burdens the overall energy balance of the engine; instead, concerning the turbine, the efficiencies of the electric generator and of the battery charging were not considered coherently with the approach followed for the main thermal engine, whose power output was not reduced by generator efficiency or by battery-charging efficiency; the reason for this approach is that the engine power split (i.e., part to the generator and part to the wheels) should depend on the particular mechanical transmission adopted and was not defined in the evaluation carried out. Moreover, both the generator and the battery-charging efficiency can also be considered the same for the comparative hybrid propulsion system equipped with the traditional turbocharged engine; on account of this, the authors decided to fairly base the comparison on the overall mechanical output power produced.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Propulsion Efficiency Increment through Exhaust Energy Recovery—Part 1: Radial Turbine Modelling and Design

et al. 2023

Self Cite

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The efficiency of Hybrid Electric Vehicles (HEVs) may be substantially increased if the energy of the exhaust gases, which do not complete the expansion inside the cylinder of the internal combustion engine, is efficiently recovered by means of a properly designed turbogenerator and employed for vehicle propulsion; previous studies, carried out by the same authors of this work, showed a potential hybrid vehicle fuel efficiency increment up to 15% by employing a 20 kW turbine on a 100 HP rated power thermal unit. The innovative thermal unit here proposed is composed of a supercharged engine endowed with a properly designed turbogenerator, which comprises two fundamental elements: an exhaust gas turbine expressly designed and optimized for the application, and a suitable electric generator necessary to convert the recovered energy into electric energy, which can be stored in the on-board energy storage system of the vehicle. In these two parts, the realistic efficiency of the innovative thermal unit for hybrid vehicle is evaluated and compared to a traditional turbocharged engine. In Part 1, the authors present a model for the prediction of the efficiency of a dedicated radial turbine, based on a simple but effective mean-line approach; the same paper also reports a design algorithm, which, owing to some assumptions and approximations, allows a fast determination of the proper turbine geometry for a given design operating condition. It is worth pointing out that, being optimized for quasi-steady power production, the exhaust gas turbine considered is quite different from the ones commonly employed for turbocharging application; for this reason, and in consideration of the required power size, such a turbine is not available on the market, nor has its development been previously carried out in the scientific literature. In the Part 2 paper, a radial turbine geometry is defined for the thermal unit previously calculated, employing the design algorithm described in Part 1; the realistic energetic advantage that could be achieved by the implementation of the turbogenerator on a hybrid propulsion system is evaluated through the performance prediction model under the different operating conditions of the thermal unit. As an overall result, it was estimated that, compared to a reference traditional turbocharged engine, the turbocompound system could gain vehicle efficiency improvement between 3.1% and 17.9%, depending on the output power level, while an average efficiency increment of 10.9% was determined for the whole operating range.

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The Potential of a Separated Electric Compound Spark-Ignition Engine for Hybrid Vehicle Application

Cited by 6 publications

References 18 publications

A Case Study Using Hydrogen Fuel Cell as Range Extender for Lithium Battery Electric Vehicle

A Case Study Using Hydrogen Fuel Cell as Range Extender for Lithium Battery Electric Vehicle

Hybrid Propulsion Efficiency Increment through Exhaust Energy Recovery—Part 2: Numerical Simulation Results

Hybrid Propulsion Efficiency Increment through Exhaust Energy Recovery—Part 1: Radial Turbine Modelling and Design

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