Location Isolability of Intake and Exhaust Manifold Leaks in a Turbocharged Diesel Engine with Exhaust Gas Recirculation

An investigation into the isolability of the location of intake and exhaust manifold leaks in heavy duty diesel engines is presented. In particular, established fault detection and isolation (FDI) methods are explored to assess their utility in successfully determining the location of a leak within the air path of an engine equipped with exhaust gas recirculation and an asymmetric twin-scroll turbine. It is further shown how consideration of the system’s variation across multiple operating points can lead to improved ability to isolate the location of leaks in the intake and exhaust manifolds. NOMENCLATURE VARIABLES AND QUANTITIES A Area (m2) CoV Coeff. of variation (-) J Inertia (kgm2) N Speed (rpm) P Pressure (Pa) R Gas const. (J/kgK) r Asymmetry ratio (-) or residual T Temperature (K) V Volume (m3) W Mass flow (kg/s) γ Spec. heat ratio (-) λ Normalized air-fuel ratio (-) μ Mean value (same as quantity) Π Pressure ratio (-) σ Standard deviation (same as quantity) Ψ Flow parameter (-) SUBSCRIPTS AND ABBREVIATIONS a Air amb Ambient c Compressor d Displacement ∗Address all correspondence to this author. EGR Exhaust gas recirc. e Engine ei Engine/cylinder in em Exhaust manifold ems Small scroll ex. man. eml Large scroll ex. man. eo Engine/cylinder out ex Exhaust f Fuel im Intake manifold in Into the volume out Out of the volume s Stoichiometric ss Steady state t Turbine tc Turbocharger tl Large turbine scroll ts Small turbine scroll u Control signal w Exogenous input x State variable/vector vol Volumetric WG Wastegate ·̄ Measured quantity ·̂ Estimated quantity