Next Article in Journal
An Analytical Approach for Design of a Cross-Connected Fibonacci Switched Capacitor Converter
Previous Article in Journal
Numerical Investigation of Pipelines Modeling in Small-Scale Concentrated Solar Combined Heat and Power Plants
Previous Article in Special Issue
Evaluation of the Brake’s Performance Dependence Upon Technical Condition of Car Tires as a Factor of Road Safety Management
Open AccessArticle

Development and Assessment of an Over-Expanded Engine to be Used as an Efficiency-Oriented Range Extender for Electric Vehicles

1
Mechanical Engineering and Resource Sustainability Centre (MEtRICs), Department of Mechanical Engineering, University of Minho, 4800-058 Guimarães, Portugal
2
Center for Innovation, Technology and Policy Research (IN+), Department of Mechanical Engineering, Instituto Superior Técnico, University of Lisbon, 1349-063 Lisbon, Portugal
*
Author to whom correspondence should be addressed.
Energies 2020, 13(2), 430; https://doi.org/10.3390/en13020430
Received: 4 December 2019 / Revised: 5 January 2020 / Accepted: 7 January 2020 / Published: 16 January 2020
(This article belongs to the Special Issue Smart Mobility and Energy Transitions)
A range extender (RE) is a device used in electric vehicles (EVs) to generate electricity on-board, enabling them to significantly reduce the number of required batteries and/or extend the vehicle driving range to allow occasional long trips. In the present work, an efficiency-oriented RE based on a small motorcycle engine modified to the efficient over-expanded cycle, was analyzed, tested and simulated in a driving cycle. The RE was developed to have two points of operation, ECO: 3000 rpm, very high efficiency with only 15 kW; and BOOST: 7000 rpm with 35 kW. While the ECO strategy was a straightforward development for the over-expansion concept (less trapped air and a much higher compression ratio) the BOOST strategy was more complicated to implement and involved the need for throttle operation. Initially the concepts were evaluated in an in-house model and AVL Boost® (AVL List Gmbh, Graz, Austria), and proved feasible. Then, a BMW K75 engine was altered and tested on a brake dynamometer. The running engine proved the initial concept, by improving the efficiency for the ECO condition in almost 40% in relation to the stock engine and getting well over the required BOOST power, getting to 35 kW, while keeping an efficiency similar to the stock engine at the wide open throttle (WOT). In order to protect the engine during BOOST, the mixture was enriched, while at ECO the mixture was leaned to further improve efficiency. The fixed operation configuration allows the reduction, not only of complexity and cost of the RE, but also the set point optimization for the engine and generator. When integrated as a RE into a typical European light duty vehicle, it provided a breakthrough consumption reduction relatively to existing plug-in hybrid electric vehicles (PHEVs) in the market in the charge sustaining mode. The very high efficiency of the power generation seems to compensate for the loss of efficiency due to the excess electricity production, which must be stored in the battery. The results indicate that indeed it is possible to have an efficient solution, in-line with the electric mobility sustainability paradigm, which can solve most of the shortcomings of current EVs, notably those associated with batteries (range, cost and charging time) in a sustainable way. View Full-Text
Keywords: range extended electric vehicle; efficiency-oriented range extender; high efficiency engine; overexpansion; series hybrid; plug-in hybrid electric vehicle range extended electric vehicle; efficiency-oriented range extender; high efficiency engine; overexpansion; series hybrid; plug-in hybrid electric vehicle
Show Figures

Figure 1

MDPI and ACS Style

Brito, F.P.; Martins, J.; Lopes, F.; Castro, C.; Martins, L.; Moreira, A.L.N. Development and Assessment of an Over-Expanded Engine to be Used as an Efficiency-Oriented Range Extender for Electric Vehicles. Energies 2020, 13, 430.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop