Analysis of cold-start related issues in a spark-ignition engine

Abstract

[ES] En aplicaciones de propulsión híbridas, el comportamiento del motor durante arranques en frío cobra una especial importancia por su alto impacto en las emisiones contaminantes emitidas por el mismo. Por este motivo se hace particularmente necesario entender los problemas que pueden surgir en dicho proceso, especialmente en condiciones climáticas adversas. En este trabajo se van a analizar dos aspectos: por un lado, el transitorio térmico de la línea de escape, que influirá sobre las prestaciones del sistema de postratamiento; por otro lado, los problemas de acumulación e ingestión de condensados producto de la operación del motor con una línea de recirculación de gases de escape. Para analizar ambos aspectos se utilizarán tanto datos experimentales en un banco de ensayos, que permitirá trabajar a distintos rangos de temperatura entre -10 y 25ºC, como simulaciones con un modelo unidimensional del motor.

[EN] Internal Combustion Engines (ICE) have come to occupy a key role in western society. They are the predominant power source for all common modes of transport, ranging from the smallest road vehicles to the largest ships. They are also one the largest sources of pollution in today’s world. Cars and vans contribute a large proportion of this pollution due, in part, to the shear number in use. While electric vehicles are becoming increasingly prevalent, battery technology has not yet reached the required point to allow electric power-trains to replace the ICE. Batteries simply do not have the required energy density and recharge rates to compete with conventional engines in remote areas or in situations where vehicles must be able to quickly cover large distances. Thus, in the short to medium term, the ICE must be optimised to work in conjunction with hybrid propulsion systems in order to provide the best of both worlds; the reduced emissions of an electric power-train when operating in full-electric mode, and the range and quick re-fill capabilities of traditionally fuelled vehicles. However, one consequence of using hybrid systems such as these is the repeated starting and stopping of the ICE. This leads to the requirement to analyse the problems associated with this operational behaviour.