Experimental Results of a Waste Heat Recovery System with Ethanol Using Exhaust Gases of a Light-duty Engine

Paper in proceeding, 2019

Organic Rankine cycle (ORC) waste heat recovery (WHR) systems have the potential to improve the efficiency of modern light-duty engines, especially at high-way driving conditions. This paper presents and discusses the experimental results of an engine connected to a compact ORC-WHR system with ethanol, suitable for integration in a modern passenger car. The aim is to show the added value of this ORC-WHR system for passenger cars by presenting the experimental results with the focus on the expander power output. The experimental setup consists of a Volvo Cars VEP-4 gasoline engine, which has an evaporator integrated in the exhaust pipe. During operation, one of two different states can be selected: electrical feedback (EFB) or mechanical feedback (MFB), where the expander can be either coupled to a 48V generator (EFB) or directly to the engine (MFB). Control strategies were developed to allow for operation of the system without interference of the driver. The results show that the current setup and control strategies can be successfully employed with significant expander power outputs for both MFB and EFB. The expander power outputs, similar for both states, go up to 2.5 kW, recovering 6.5% of the available exhaust energy and giving more than 5% improvement in fuel consumption.