Effect of Ethanol-Gasoline Blends on In-Cylinder Pressure and Brake-Specific Fuel Consumption at Various Engine Speeds

Abstract

This study investigates the impact of ethanol-gasoline blends on in-cylinder pressure and brake-specific fuel consumption (BSFC) at various engine speeds and throttle positions. Experiments were conducted using RON95 gasoline and ethanol blends of E10, E20, and E30 at engine speeds of 1000 rpm, 2000 rpm, and 3000 rpm. The in-cylinder pressure analysis at 2000 rpm showed that the highest peak pressure was achieved with RON95 at 590 kPa, while E10, E20, and E30 recorded 585 kPa, 580 kPa, and 575 kPa, respectively. Interestingly, at 3000 rpm, E30 exhibited the highest peak pressure of 830 kPa, followed by E20 (810 kPa), E10 (790 kPa), and RON95 (770 kPa), indicating that higher ethanol content improves combustion at higher engine speeds. BSFC measurements revealed that increasing ethanol content led to higher fuel consumption. At 1000 rpm with 40% throttle, BSFC increased from 7.1 g/kWh (RON95) to 7.6 g/kWh (E30). Similarly, at 2000 rpm with 40% throttle, BSFC rose from 32.2 g/kWh for RON95 to 34.1 g/kWh for E30. The highest BSFC values were recorded at 3000 rpm and 45% throttle, where RON95 measured 102 g/kWh and E30 reached 106 g/kWh. These findings demonstrate that ethanol blends can enhance in-cylinder pressure at high engine speeds but increase fuel consumption due to ethanol's lower calorific value. This research provides significant insights into optimizing ethanol-gasoline blends for improved combustion efficiency while considering fuel economy in gasoline-powered engines.