Six Degrees Crankshaft Individual Air Fuel Ratio Estimation of Diesel Engines for Cylinder Balancing Purpose

In the context of modern engine control, one important variable is the individual Air Fuel Ratio (AFR) which is a good representation of the produced torque. It results from various inputs such as injected quantities, boost pressure, and the exhaust gas recirculation (EGR) rate. Further, for forthcoming HCCI engines and regeneration filters (Particulate filters, DeNOx), even slight AFR un- balance between the cylinders can have dramatic conse- quences and induce important noise, possible stall and higher emissions. Classically, in Spark Ignition engine, overall AFR is directly controlled with the injection system. In this approach, all cylinders share the same closed- loop input signal based on the single ¸-sensor (normal- ized Fuel-Air Ratio measurement, it can be rewritten with the total and air masses in the exhaust manifold as ¸ , 1 i M air MT ). Ideally, all the cylinders would have the same AFR as they have the same injection set-point. Unfortu- nately, due to inherent flaws of the injection system (pres- sure waves, mechanical tolerances, ...), the total mass of fuel injected in each cylinder is very difficult to predict wi th a relative precision better than 7%. Having a sensor in each cylinder would enable an accurate individual con- trol. In practice, cost and reliability of multiple ¸-sensors prevent them from reaching commercial products lines. In this context, individual cylinder AFR estimation can give crucial information to get the HCCI running better. The contribution of this paper is the design and experi- mental tests of a real-time observer for the individual cylin- der AFR using the reliable and available ¸-sensor placed downstream the turbine as only measurement. In pre- vious works, the methods used to reconstruct the AFR of each cylinder from the UEGO (Universal Exhaust Gas Oxygen) ¸-sensor measurement are based on the permu- tation dynamics at the TDC (Top-Dead Center) time-scale and a gain identification technique. Here, we propose a higher frequency approach (6 degree crankshaft angle modelling and update instead of 180(TDC)). We design an observer on the balance model of the exhaust and de- sign a high frequency observer to solve the problem. We use a physics-based model underlying the role of periodic input flows (gas flows from the cylinders into the exhaust manifold). The observer is validated experimentally on a 4 cylinder HCCI engine. As a conclusion, we provide re- sults of closed-loop control using the proposed technique to prove the relevance of this approach.

[1]  Lino Guzzella,et al.  Control of diesel engines , 1998 .

[2]  D. Lindner,et al.  Advanced exhaust gas aftertreatment systems for gasoline and diesel fuelled vehicles , 1996 .

[3]  Theophil S. Auckenthaler,et al.  Aspects of Dynamic Three-Way Catalyst Behaviour Including Oxygen Storage , 2004 .

[4]  Claudio Carnevale,et al.  Cylinder To Cylinder AFR Control With An Asymmetrical Exhaust Manifold in a GDI System , 1998 .

[5]  B. Gatellier,et al.  Near Zero NOx Emissions and High Fuel Efficiency Diesel Engine: the Naditm Concept Using Dual Mode Combustion , 2003 .

[6]  Yann Guezennec,et al.  A Novel Approach to Real-Time Estimation of the Individual Cylinder Combustion Pressure for S.I. Engine Control , 1999 .

[7]  John B. Heywood,et al.  Internal combustion engine fundamentals , 1988 .

[8]  Yann Guezennec,et al.  Crankangle Based Torque Estimation: Mechanistic / Stochastic , 2000 .

[9]  Brendan Carberry,et al.  Diesel Particulate Filter Regeneration: Control of Calibration? , 2004 .

[10]  F. Chmela,et al.  Rate of Heat Release Prediction for Direct Injection Diesel Engines Based on Purely Mixing Controlled Combustion , 1999 .

[11]  J.W. Grizzle,et al.  Individual Cylinder Air-Fuel Ratio Control with a Single EGO Sensor , 1990, 1990 American Control Conference.

[12]  Giorgio Rizzoni,et al.  Estimate of indicated torque from crankshaft speed fluctuations: a model for the dynamics of the IC engine , 1989 .

[13]  Konstantinos Boulouchos,et al.  A Phenomenological Combustion Model for Heat Release Rate Prediction in High-Speed DI Diesel Engines with Common Rail Injection , 2000 .

[14]  G. Corde,et al.  1D Simulation of Turbocharged Gasoline Direct Injection Engine for Transient Strategy Optimization , 2005 .

[15]  G. Corde,et al.  Real-time combustion torque estimation on a diesel engine test bench using an adaptive Fourier basis decomposition , 2004, 2004 43rd IEEE Conference on Decision and Control (CDC) (IEEE Cat. No.04CH37601).

[16]  Jon Rigelsford,et al.  Automotive Control Systems: For Engine, Driveline and Vehicle , 2004 .

[17]  Bengt Johansson,et al.  Reacting Boundary Layers in Homogeneous Charge Compression Ignition (HCCI) Engine , 2001 .

[18]  F. Le Berr,et al.  Application of a New 1D Combustion Model to Gasoline Transient Engine Operation , 2005 .

[19]  P. Rouchon,et al.  Real-time combustion torque estimation on a diesel engine test bench using time-varying Kalman filtering , 2004, 2004 43rd IEEE Conference on Decision and Control (CDC) (IEEE Cat. No.04CH37601).

[20]  Elbert Hendricks,et al.  Mean Value Modeling of a Small Turbocharged Diesel Engine , 1991 .

[21]  Bertrand Gatellier,et al.  Development of the High Power NADI™ Concept Using Dual Mode Diesel Combustion to Achieve Zero NOx and Particulate Emissions , 2002 .

[22]  Pierre Rouchon,et al.  Periodic Input Observer Design: Application for Imbalance Diagnosis , 2006 .

[23]  Kai Behnk,et al.  Development scenario for passenger-car diesel engines with optimised: Combustion processes to meet future emission standards , 2003 .

[24]  Ilya Kolmanovsky,et al.  Turbocharger Modeling for Automotive Control Applications , 1999 .

[25]  Philippe Moulin,et al.  REAL-TIME NONLINEAR INDIVIDUAL CYLINDER AIR FUEL RATIO OBSERVER ON A DIESEL ENGINE TEST BENCH , 2005 .

[26]  J. Fantini,et al.  Exhaust - Intake Manifold Model for Estimation of Individual Cylinder Air Fuel Ratio and Diagnostic of Sensor - Injector , 2003 .