Abstract
Stringent exhaust emission and fuel consumption regulations impose the need for new solutions for further development of internal combustion engines. With this in mind, a refined control of the combustion process in each cylinder can represent a useful and affordable way to limit cycle-to-cycle and cylinder-to-cylinder variation reducing CO2 emission. In this paper, a twin-cylinder turbocharged Port Fuel Injection–Spark Ignition engine is experimentally and numerically characterized under different operating conditions in order to investigate the influence of cycle-to-cycle variation and cylinder-to-cylinder variability on the combustion and performance. Significant differences in the combustion behavior between cylinders were found, mainly due to a non-uniform effective in-cylinder air/fuel (A/F) ratio. For each cylinder, the coefficients of variation (CoVs) of selected combustion parameters are used to quantify the cyclic dispersion. Experimental-derived CoV correlations representative of the engine behavior are developed, validated against the measurements in various speed/load points and then coupled to an advanced 1D model of the whole engine. The latter is employed to reproduce the experimental findings, taking into account the effects of cycle-to-cycle variation. Once validated, the whole model is applied to optimize single cylinder operation, mainly acting on the spark timing and fuel injection, with the aim to reduce the specific fuel consumption and cyclic dispersion.
Highlights
Stringent exhaust emission and fuel consumption regulations always impose the need for new solutions for further development of internal combustion engines
This paper presents experimental and 1D numerical investigations performed on a twin-cylinder turbocharged Port Fuel Injection (PFI) Spark Ignition engine in order to study the influence of cycle-to-cycle and cylinder-to-cylinder variations on combustion and performance under different operating conditions
As already reported previous sections, the operating points measured in the variation entire engine parameters ininorder to provide a valuable prediction of the cycle-to-cycle in domain
Summary
Stringent exhaust emission and fuel consumption regulations always impose the need for new solutions for further development of internal combustion engines. Turbochargers are characterized by maximum allowed values of temperature to avoid an excessive thermal stress for the turbine blades; in order to maintain exhaust temperatures below this limit and to reduce the knock tendency at high load and low speed, fuel enrichment is often used The latter control strategy obviously deteriorates the fuel consumption of the vehicle. This paper presents experimental and 1D numerical investigations performed on a twin-cylinder turbocharged Port Fuel Injection (PFI) Spark Ignition engine in order to study the influence of cycle-to-cycle and cylinder-to-cylinder variations on combustion and performance under different operating conditions. The model was applied to optimize the single cylinder operation, equipped with a Variable Valve Actuation (VVA) device for a flexible control of the intake lift strategy mainly acting on the spark timing andfixed fuel injection, with the aim to reduce the indicated specific fuel while the exhaust valves present both lift and timing.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
