On-Board Indicated Pressure and Torque Estimation in Engines With a High Number of Cylinders

2002 ◽  
Author(s):  
Enrico Corti ◽  
Davide Moro
Keyword(s):  
Control Strategy ◽  
Engine Speed ◽  
Fuel Injection ◽  
Control Strategies ◽  
Engine Control ◽  
Cylinder Pressure ◽  
Signal Processing Algorithm ◽  
Operating Condition ◽  
Torque Estimation ◽  
Speed Fluctuations

In recent years engine control development focused the attention on torque-based models, that allow improving driveability and implementing traction control strategies. The design of such a torque-based engine control strategy requires the knowledge of the torque produce by the engine, which depends on fuel injection time, spark advance, throttle opening, EGR command, … In the actual engine control strategies this is mainly done by means of static maps stored in the ECU memory. The real engine torque production under every operating condition can be evaluated by means of the in-cylinder pressure estimation, thus allowing a torque based closed loop control strategy. Many approaches are present in the literature showing the possibility of on-board estimating the actual torque produced by the engine not simply by using static maps, but estimating it through other measured signals. Most of the methodologies that do not require a specific sensor placed on the engine are based either on the engine speed fluctuations (measured by a pick-up facing the flywheel teeth) or on the engine block vibrations (measured by the knock sensor), performing better for engines with a low number of cylinders. The paper presents an original methodology based on the instantaneous engine speed fluctuations, that has been usefully applied to engines with higher number of cylinders. The methodology is based on the observation of the speed fluctuations in a crankshaft window inside the expansion stroke and on the hypothesis that there exists a strong correlation between these engine speed fluctuations and pressure inside the selected cylinder. This relationship has been characterized using Frequency Response Functions (FRF) for each steady-state engine operating condition. In the following the FRFs have been used to perform in-cylinder pressure and then indicated torque estimation under every operating condition, and a specific signal processing algorithm has been developed in order to apply the procedure during speed and load engine transients. The experimental tests have been conducted mounting a six-cylinder turbo-charged spark-ignited engine in a test cell. The application on-board a vehicle of the same methodology seems to be feasible due to the quickness of the algorithm employed and the presence on-board of all the sensors required for the implementation.

Turbocharged Diesel Engine Modeling for Nonlinear Engine Control and State Estimation

1995 ◽  
Vol 117 (1) ◽  
pp. 20-30 ◽  
Author(s):  
Minghui Kao ◽  
John J. Moskwa
Keyword(s):  
Diesel Engine ◽  
State Estimation ◽  
Engine Speed ◽  
Fuel Injection ◽  
Production Model ◽  
Injection Timing ◽  
Engine Control ◽  
Cylinder Pressure ◽  
Engine Modeling ◽  
Cylinder Model

Engine models that are used for nonlinear diesel engine control, state estimation, and model-based diagnostics are presented in this paper. By collecting, modifying, and adding to current available engine modeling techniques, two diesel engine models, a mean torque production model and a cylinder-by-cylinder model, are summarized for use in the formulation of control and state observation algorithms. In the cylinder-by-cylinder model, a time-varying crankshaft inertia model is added to a cylinder pressure generator to simulate engine speed variations due to discrete combustion events. Fuel injection timing and duration are control inputs while varying engine speed, cylinder pressure, and indicated torque are outputs from simulation. These diesel engine models can be used as engine simulators and to design diesel engine controllers and observers.

Engine Torque Non-Uniformity Evaluation Using Instantaneous Crankshaft Speed Signal

2001 ◽  
Author(s):  
Nicolò Cavina ◽  
Fabrizio Ponti
Keyword(s):  
Engine Speed ◽  
Combustion Engine ◽  
Control Strategies ◽  
Ignition Time ◽  
Operating Conditions ◽  
Injection System ◽  
Engine Torque ◽  
Production Variability ◽  
The One ◽  
Speed Fluctuations

Abstract The paper presents the development of a methodology for evaluating the torque non-uniformity between the various cylinders of an Internal Combustion Engine (ICE). This non-uniformity can be due, for example, to pathological operating conditions such as misfires or misfuels, as well as to other abnormal operating conditions. Between the nominal torque production and the one corresponding to the absence of combustion there exist, in fact, a series of possible intermediate conditions. Each of them corresponds to a value of produced torque that lies between the nominal value and the one corresponding to the lack of combustion (due for example to statistical dispersion in manufacturing or aging in the injection system). The diagnosis of this type of non-uniformity is a very important issue in today’s engine control strategies design. The use of the developed methodology should in fact allow the control strategy to adopt the appropriate interventions if the diagnosed non-uniformity is related to different behavior of the injectors. In order to evaluate this torque production variability between the various cylinders, information hidden in the instantaneous crankshaft speed fluctuations has been processed using a suitable methodology. The procedure has been validated running a supercharged 2.0 liters V6 engine, and a 1.2 liters L4 engine, in a test cell. During the tests, the in-cylinder pressure signal has been acquired together with the instantaneous engine speed, in order to determine a correlation between speed fluctuations and the indicated torque produced by each cylinder. The actual cylinder by cylinder torque non-uniformity can then be evaluated on-board by processing engine speed. The procedure is able to diagnose the absence of combustion (due for example to a misfire or a misfuel) as well as abnormal combustions that do not necessarily involve lack of combustion, with the accuracy needed for on-board use. Control interventions to injection and ignition time commands of one or more cylinders should in most cases be able to re-establish torque production uniformity.

Engine Torque Nonuniformity Evaluation Using Instantaneous Crankshaft Speed Signal

2003 ◽  
Vol 125 (4) ◽  
pp. 1050-1058 ◽  
Author(s):  
N. Cavina ◽  
F. Ponti
Keyword(s):  
Engine Speed ◽  
Combustion Engine ◽  
Control Strategies ◽  
Ignition Time ◽  
Operating Conditions ◽  
Injection System ◽  
Engine Torque ◽  
Production Variability ◽  
The One ◽  
Speed Fluctuations

The paper presents the development of a methodology for evaluating the torque nonuniformity between the various cylinders of an internal combustion engine (ICE). This nonuniformity can be due, for example, to pathological operating conditions such as misfires or misfuels, as well as to other abnormal operating conditions. Between the nominal torque production and the one corresponding to the absence of combustion there exist, in fact, a series of possible intermediate conditions. Each of them corresponds to a value of produced torque that lies between the nominal value and the one corresponding to the lack of combustion (due for example to statistical dispersion in manufacturing or aging in the injection system). The diagnosis of this type of nonuniformity is a very important issue in today’s engine control strategies design. The use of the developed methodology should in fact allow the control strategy to adopt the appropriate interventions if the diagnosed nonuniformity is related to different behavior of the injectors. In order to evaluate this torque production variability between the various cylinders, information hidden in the instantaneous crankshaft speed fluctuations has been processed using a suitable methodology. The procedure has been validated running a supercharged 2.0 liters V6 engine, and a 1.2 liters L4 engine, in a test cell. During the tests, the in-cylinder pressure signal has been acquired together with the instantaneous engine speed, in order to determine a correlation between speed fluctuations and the indicated torque produced by each cylinder. The actual cylinder-by-cylinder torque nonuniformity can then be evaluated on-board by processing engine speed. The procedure is able to diagnose the absence of combustion (due for example to a misfire or a misfuel) as well as abnormal combustions that do not necessarily involve lack of combustion, with, the accuracy needed for on-board use. Control interventions to injection and ignition time commands of one or more cylinders should, in most cases, be able to re-establish torque production uniformity.

In-Cylinder Pressure Measurement: Requirements for On-Board Engine Control

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Fabrizio Ponti
Keyword(s):  
Data Storage ◽  
Control Strategies ◽  
Electronic Control Unit ◽  
Low Cost ◽  
Low Frequency ◽  
Control Unit ◽  
Engine Control ◽  
Cylinder Pressure ◽  
Diagnostic Strategies ◽  
Denox Catalysts

During these last years, passenger vehicles have been equipped with an increasing number of sensors, in an effort to monitor and control their behavior in terms of global performance and emissions. This, together with constantly increasing electronic control unit computing power and data storage capabilities, allowed the development of more efficient engine-vehicle control strategies. In this perspective, new sensors will be employed as soon as their use will be shown to be necessary to design new engine control and diagnostic strategies, and their cost and expected life will be compatible with on-board application. A sensor that has been largely studied in recent years is the in-cylinder pressure one: advanced engine control strategies that make use of the signal coming from such a sensor have been investigated, while reliable and low-cost sensors are being developed to survive for the vehicle life the harsh on-board environment. The signal coming from the in-cylinder pressure is, in fact, very rich in information and could be used, for example, to improve engine torque management (by directly computing the instantaneous indicated torque), to improve air∕fuel ratio control, misfire and knock detection capabilities, engine emission estimation (to be used for DeNOx catalysts purging management as an example), residual gas fraction estimation, etc. Many sensor concepts have been developed, although none seems to actually fully meet both the precision and low-cost requirements necessary for on-board application. This work deals with defining the sensor precision characteristics necessary to effectively implement the aforementioned engine control and diagnostic capabilities improvements. In particular, it will be shown that only the low-frequency signal content has to be precisely measured and is critical for certain application. In addition, the importance of a correct reference of the in-cylinder pressure signal is discussed, and a novel methodology to quickly obtain this information once the engine has been setup with a proper in-cylinder pressure sensor is discussed.

Analysis of the Interactions Between Indicated and Reciprocating Torques for the Development of a Torsional Behavior Model of the Powertrain

2007 ◽  
Author(s):  
Fabrizio Ponti ◽  
Luca Solieri
Keyword(s):  
Engine Speed ◽  
Behavior Model ◽  
Identification Process ◽  
Speed Measurement ◽  
Torque Estimation ◽  
Crank Angle ◽  
Torsional Behavior ◽  
Correct Estimation ◽  
Speed Fluctuations ◽  
The Relationship

Torque-based engine control systems usually employ a produced torque estimation feedback in order to verify that the strategy target torque has been met. Torque estimation can be performed using static maps describing the engine behaviour or using models describing the existing relationships between signals measured on the engine and the indicated torque produced. Signals containing information on the combustion development, suitable for this purpose, are, among other, the ion-current signal, the vibration signals obtained from accelerometers mounted on the engine block, or the instantaneous engine speed fluctuations. This paper presents the development and the identification process of an engine-driveline torsional behavior model that enables indicated torque estimation from instantaneous engine speed measurement. Particular attention has been devoted to the interactions between indicated and reciprocating torques, and their effects over instantaneous engine speed fluctuations. Indicated and reciprocating torques produce, in fact, opposite excitations on the driveline that show opposite effects on the engine speed waveform: for low engine speed usually indicated torque prevails, while the opposite applies for higher engine speed. In order to correctly estimate indicated torque from engine speed measurement it is therefore necessary to correctly evaluate the reciprocating torque contribution. Reciprocating torque is usually described using a waveform as a function of crank angle, while its amplitude depends on the value of the reciprocating masses. As mentioned before, knowledge of the reciprocating masses is fundamental in order to obtain correct estimation of the indicated torque. The identification process that has been setup for the engine-driveline torsional model enables to evaluate the relationship between torques applied to the engine and the corresponding engine speed waveform even without knowing the value of the reciprocating masses. In addition, once this model has been setup, it is possible to estimate with high precision the value of the reciprocating masses. Particular attention has been devoted also to the feasibility of the application of the identified model on-board for torque estimation; for this reason the model has been developed in a very simple form. The approach proved to be effective both on gasoline and diesel engine, both for engine mounted on a test cell and on-board, with different engine configurations. Examples of application are given for some of the configurations investigated.

scholarly journals Idling Performance under Valve Deactivation Strategy in Port Fuel Injection Engine

2019 ◽  
Vol 16 (4) ◽  
pp. 7155-7169
Author(s):  
A. S. Paimon ◽  
S. Rajoo ◽  
W. Jazair ◽  
M. A. Abas ◽  
Z. H. Che Daud
Keyword(s):  
Coefficient Of Variation ◽  
Engine Speed ◽  
Fuel Injection ◽  
Swirl Flow ◽  
Combustion Stability ◽  
Cylinder Pressure ◽  
Fuel Injector ◽  
Port Fuel Injection ◽  
Indicated Mean Effective Pressure ◽  
Significant Difference

This paper investigates the effect of valve deactivation (VDA) on idling performance in port fuel injection (PFI) engine. The test was conducted on 1.6L, 4-cylinder engine with PFI configuration. One of the two intake valves in each cylinder was deactivated (zero lift on deactivated port) and fuel injector was modified to only provide fuel spray on the active intake port. In-cylinder pressure was recorded by the combustion analyzer in order to measure and analyze the combustion characteristics. From the test, there are up to 6% of fuel consumption improvements across all the test conditions. Better combustion stability is achieved at very low idling speed (throttle position, TP = 2%) as a lower coefficient of variation of engine speed (COVrpm) and coefficient of variation indicated mean effective pressure (COVimep) were recorded. Increased intake velocity and swirl flow in the VDA strategy creates more turbulence intensity causing higher heat release rate and faster combustion. However, there is no significant difference in the pumping work during the intake cycle but there is extra pumping work recorded towards the end of expansion stroke due to the very early end of combustion. Therefore, valve deactivation strategy provides limited positive improvement to the idling performance in PFI engine.

Analysis of the Relationship Between Mean Indicated Torque and Its Waveform for Modern Common Rail Diesel and Gasoline Engines

2008 ◽  
Author(s):  
Fabrizio Ponti ◽  
Matteo Rinaldi
Keyword(s):  
Engine Speed ◽  
Gasoline Engine ◽  
Management Strategies ◽  
System Model ◽  
Gasoline Engines ◽  
Torque Estimation ◽  
Speed Fluctuation ◽  
Harmonic Components ◽  
Speed Fluctuations ◽  
The Relationship

The paper presents the progresses made for the development of a methodology useful for torque estimation, necessary in modern management strategies in order to obtain an indication of the torque produced by the engine. The model developed allows estimating mean indicated torque, cylinder by cylinder, based on instantaneous engine speed fluctuations. The speed signal is picked up directly from the sensor facing the toothed wheel mounted on the engine for control purposes. The engine speed fluctuation amplitudes depend in fact on the combustion and the amount of torque that is being delivered by each cylinder. It is easy to understand therefore how these two quantities, engine speed fluctuation amplitudes and torque production, are strictly connected. The presented methodology is based on two main steps. The first step relies on the identification of the dynamic system model that allows to get torque harmonic from the corresponding engine speed components. The identification could be done by two methods, the first one requiring the knowledge of the value of the reciprocating masses with high precision, and the other one making use of different tests at the same speed but with different loads, in order to estimate separately both the reciprocating masses and the system model. The second step, which constitutes the main focus of this paper, relies on the identification of the relationship between the mean indicated torque and its harmonics. The study of this relationship has been carried out in particular in this paper for a multijet diesel engine and for a gasoline engine. Many tests were performed on different driveline configuration, both in a test-cell, and on-board. Once indicated torque and its harmonic components have been evaluated from in-cylinder pressure signals, identification of the relationship has been possible. Influence of the type of combustion performed has been discussed, as also the effects related to cylinder filling and injection timings.

Torque estimation of spark ignition engines via cylinder pressure measurement

2003 ◽  
Vol 217 (9) ◽  
pp. 809-817 ◽  
Author(s):  
Seungbum Park ◽  
Myoungho Sunwoo
Keyword(s):  
Engine Management System ◽  
Engine Control ◽  
Spark Ignition Engines ◽  
Cylinder Pressure ◽  
Load Torque ◽  
Engine Torque ◽  
Estimation Algorithms ◽  
Torque Estimation ◽  
Feasible Alternative ◽  
Vehicle Dynamics Control

Indicated torque estimation and load torque observation algorithms are presented and appear to be a feasible alternative to the use of the engine torque maps in a modern torque-based engine management system. The proposed method, which uses a cylinder pressure sensor, has advantages of simplicity from the elimination of the requirement for a complex indicated torque model. Moreover, the proposed algorithms are accurate and robust to the variations in the environmental factors that affect the torque production procedure. The indicated torque is estimated from the peak pressure and its location, and the load torque is observed on the basis of the estimated indicated torque. The proposed torque estimation algorithms may provide new ideas for many application areas such as engine diagnostics, torque-based engine control, traction control via engine control, and vehicle dynamics control.

Air Fuel Ratio Estimation Using In-Cylinder Pressure Frequency Analysis

2003 ◽  
Vol 125 (3) ◽  
pp. 812-819 ◽  
Author(s):  
N. Cavina ◽  
F. Ponti
Keyword(s):  
Frequency Analysis ◽  
Closed Loop ◽  
Fuel Injection ◽  
Combustion Engine ◽  
Control Strategies ◽  
Feedback Signal ◽  
Exhaust Gas ◽  
Cylinder Pressure ◽  
Passenger Cars ◽  
Fuel Ratio

This paper presents an original approach to estimate the air-fuel ratio (AFR) of the mixture that burned inside a given cylinder of a spark-ignited (SI) internal combustion engine, using the information hidden in the corresponding in-cylinder pressure signal. In modern closed-loop fuel injection control strategies, the feedback signal is usually given by one (or more) heated exhaust gas oxygen (HEGO) sensor(s), mounted in the exhaust manifold(s). The information that such sensors give is related to the stoichiometry of the mixture that burned inside the cylinders. The HEGO sensor is not able to evaluate the AFR value precisely, being only able to determine whether the mixture was rich or lean. This information is sufficient to allow the implementation of a closed-loop strategy for injection time control. Generally speaking, such strategy could be improved in terms of readiness and precision by directly measuring (or by estimating) the actual AFR. Universal exhaust gas oxygen (UEGO) sensors are still considered expensive and their use is mostly limited to laboratory and racing applications, even if some automotive manufacturers have started installing such sensors on board passenger cars, as part of an effort to comply with ULEV (ultra low emission vehicles) regulations. For this reason the idea of estimating AFR values from other signals has received great attention in the past few years. A new approach based on in-cylinder pressure frequency analysis is presented here.

Engine Control Using Estimated Parameters From a Real Time Model of an Engine With Variable Valve Actuation

2005 ◽  
Author(s):  
John L. Lahti ◽  
John J. Moskwa
Keyword(s):  
Real Time ◽  
Mass Fraction ◽  
Fuel Injection ◽  
Exhaust System ◽  
Time Estimation ◽  
Exhaust Gas ◽  
Engine Control ◽  
Cylinder Pressure ◽  
Time Model ◽  
Residual Mass

A real time model of an engine was developed and integrated with engine control software to provide better engine control with less calibration effort. The model uses one-dimensional compressible gas wave equations for the intake and exhaust system along with a thermodynamic model of the cylinder to provide real time estimation of the cylinder air charge, exhaust gas residual mass fraction, cylinder pressure, cylinder temperature, and various other states along the intake and exhaust system. Information from the model is used to control the fuel injection, spark advance, valve timing, and throttle position on the actual engine. The system does not use any volumetric efficiency tables. Since the real time model responds like the actual engine there is no need for transient fuel or transient spark advance correction factors. The estimated cylinder pressure is used to calculate the instantaneous indicated engine torque and engine efficiency. Using the model it is possible to optimize efficiency, control the torque output, and regulate the exhaust gas residual mass fraction. The system offers many control advantages and is easy to calibrate.

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