A New Electronic Ethanol Injection Management System for Diesel Engines

Abstract

This work shows an electronic management system equipped with two microcontrollers for ethanol injection in the air intake pipe of a diesel engine. The aim was to reduce the NOx emissions, while increasing the amount of renewable fuel in the mixture. The system was specially developed to detect the high-pressure pulse in the diesel injection line and to trigger the ethanol injection. An intrusive pressure sensor was installed in the diesel injection pipe to allow the measurement. Through a security protocol, the timing and duration of injection can be adjusted. The system evaluates the temperature reduction caused by the ethanol injection using two NTC thermal sensors. The exhaust gas temperature was determined by a type K thermocouple. The system was tested in a single cylinder diesel generator with mechanical injection at 1,750, 1,800, and 1,850 rpm in order to verify the injection frequency, the injection delays, the NOx emissions and the intake air, and exhaust gas temperature variation. It was found that the injection delays were less than 850 $\mu$s. A reduction in the intake air and exhaust gas temperatures was observed as the ethanol content increased. Injections of 15 v/v% ethanol into the intake air pipe have shown a considerable reduction (60 %) in NOx emissions when compared to diesel-biodiesel blend composed of 70 v/v% mineral diesel and 30 v/v% soybean biodiesel. It was demonstrated that the addition of ethanol can be an important method to reduce the amount of NOx in the exhaust gas of Diesel engines.