A Two-Stroke Range Extender Engine For Heavy Duty BEV applications

A back-up range extender (REX) is proposed to support battery electric vehicles (BEV) for heavy duty applications. A single cylinder crank case scavenged two-stroke SI-internal combustion engine (ICE) with a turbocharger system is considered powerful and small enough to be installed directly on the existing electric machine in the electric powertrain. The two-stroke engine needs a specially designed turbocharger system assisted by an afterburner system to fulfill the scavenging and exhaust emission requirements. This thesis has investigated and developed such a charging system functionality and demonstrated it on a 125cc engine single cylinder engine. This shows that a 125cc single cylinder two- stroke engine was able to obtain 50 kW or 400 kW/L swept volume indicating that an upscaled version of this engine to 425cc will be able to produce the desired rated power of 150 kW

A Two-Stroke Range Extender Engine for Heavy Duty Battery Electric vehicle applications

Turbo, two-stroke, range extender, BE

Evaluation of a Back-up Range Extender and Other Heavy-Duty BEV-Supporting Systems

Electric powertrains in terms of battery electric vehicles (BEV) are considered to be very interesting for heavy truck transportations. The challenge is the need for very large onboard energy and batteries. Long-term fuel cells (FCs) are considered an interesting support system for heavy-duty BEV, but in the short term, a range extender (REX) is also interesting. A heavy-duty BEV with 970 kWh batteries installed can handle 27% of all possible missions for the Scania fleet considering daily recharging. The back-up range extender (BUREX) can expand this figure to 55% utilized 20 days per year. If a customer has a few very energy-demanding use cases each year and does not want to pay for all the batteries needed, the BUREX may be an especially good option. The BUREX reduces life-cycle CO2 emissions, irrespective of the generation mix of the grid supplying the electricity used in vehicle manufacturing and battery charging. The BUREX reuse of the existing electric components of the BEV powertrain enables the installation of a 10% larger battery pack while being 80% less costly. The BUREX also adds redundancy to the BEV concept while recharging infrastructure improves, especially in rural places. These results indicate that the BUREX concept is a powerful short-term solution that could enable greater use of HD FC and BEV trucks while charging infrastructure and FC technologies gradually become more mature

Analysis of a Turbocharged Single-Cylinder Two-Stroke SI Engine Concept

Power dense internal combustion engines (ICEs) are interesting candidates for onboard charging devices in different electric powertrain applications where the weight, volume and price of the energy storage components are critical. Single-cylinder naturally aspirated two-stroke spark-ignited (SI) engines are very small and power dense compared to four-stroke SI engines and the installation volume from a single cylinder two-stroke engine can become very interesting in some concepts. During charged conditions, four-stroke engines become more powerful than naturally aspirated two-stroke engines. The performance level of a two-stroke SI engines with a charging system is less well understood since only a limited number of articles have so far been published. However, if charging can be successfully applied to a two-stroke engine, it can become very power dense. This article outlines some of the challenges related to charging systems for a single-cylinder crank case scavenged two-stroke SI engine. Different charging scenarios were investigated and a charging system was selected and optimized to meet the scavenging and gas exchange needs of two-stroke engine. A 125 cc single-cylinder two-stroke engine with a turbocharger was simulated and tested successfully to a performance level of 400 kW/L