Tolerant Ethanol Estimation in Flex-Fuel Vehicles During MAF Sensor Drifts

2009 ◽  
Author(s):  
Kyung-ho Ahn ◽  
Anna G. Stefanopoulou ◽  
Mrdjan Jankovic
Keyword(s):  
Oxygen Sensor ◽  
Air Flow ◽  
Intake Manifold ◽  
Absolute Pressure ◽  
Exhaust Gas ◽  
Fuel Ratio ◽  
Ethanol Content ◽  
Sensor Drift ◽  
Flex Fuel ◽  
The Difference

Flexible fuel vehicles (FFVs) can operate on a blend of ethanol and gasoline in any volumetric concentration of up to 85% ethanol (93% in Brazil). Existing FFVs rely on ethanol sensor installed in the vehicle fueling system, or on the ethanol-dependent air-to-fuel ratio (AFR) estimated via an exhaust gas oxygen (EGO) or λ sensor. The EGO-based ethanol detection is desirable from cost and maintenance perspectives but has been shown to be prone to large errors during mass air flow sensor drifts [1, 2]. Ethanol content estimation can be realized by a feedback-based fuel correction of the feedforward-based fuel calculation using an exhaust gas oxygen sensor. When the fuel correction is attributed to the difference in stoichiometric air-to-fuel ratio (AFR) between ethanol and gasoline, it can be used for ethanol estimation. When the fuel correction is attributed to a mass air flow (MAF) sensor error, it can be used for sensor drift estimation and correction. Deciding under which condition to blame (and detect) ethanol and when to switch to sensor correction burdens the calibration of FFV engine controllers. Moreover, erroneous decisions can lead to error accumulation in ethanol estimation and in MAF sensor correction. In this paper, we present a cylinder air flow estimation scheme that accounts for MAF sensor drift or bias using an intake manifold absolute pressure (MAP) sensor. The proposed fusion of the MAF, MAP and λ sensor measurements prevents severe mis-estimation of ethanol content in flex fuel vehicles.

Estimation of Ethanol Content in Flex-Fuel Vehicles Using an Exhaust Gas Oxygen Sensor: Model, Tuning and Sensitivity

2008 ◽  
Author(s):  
Kyung-Ho Ahn ◽  
Anna G. Stefanopoulou ◽  
Mrdjan Jankovic
Keyword(s):  
Oxygen Sensor ◽  
Control Process ◽  
Engine Management System ◽  
Exhaust Gas ◽  
Fuel Blend ◽  
Analysis And Design ◽  
Sensor Model ◽  
Ethanol Content ◽  
Model Tuning ◽  
Adaptation Law

Throughout the history of the automobile there have been periods of intense interest in using ethanol as an alternative fuel to petroleum-based gasoline and diesel derivatives. Currently available flexible fuel vehicles (FFVs) can operate on a blend of gasoline and ethanol in any concentration of up to 85% ethanol. In all these FFVs, the engine management system relies on the estimation of the ethanol content in the fuel blend, which typically depends on the estimated changes in stoichiometry through an Exhaust Gas Oxygen (EGO) sensor. Since the output of the EGO sensor is used for the air-to-fuel ratio (AFR) regulation and the ethanol content estimation, several tuning and sensitivity problems arise. In this paper, we develop a simple phenomenological model of the AFR control process and a simple ethanol estimation law which can be representative of the currently practiced system in FFVs. Tuning difficulties and interactions of the two learning loops are then elucidated using classical control techniques. The sensitivity of the ethanol content estimation with respect to sensor and modeling errors is also demonstrated via simulations. The results point to an urgent need for model-based analysis and design of the AFR controller, the ethanol adaptation law and the fault detection issues in FFVs. Tuning and sensitivity issues are demonstrated via simulations and limitations are also discussed.

Adaptive Air Fuel Ratio Controls in Presence of Oxygen Sensor Faults

2015 ◽  
Author(s):  
Hassene Jammoussi ◽  
Imad Makki
Keyword(s):  
Oxygen Sensor ◽  
Test Procedure ◽  
Smith Predictor ◽  
Exhaust Gas ◽  
Sensor Faults ◽  
Sensor Fault ◽  
Fuel Ratio ◽  
Fault Monitoring ◽  
The Stability ◽  
Rapid Prototyping System

Fault monitoring of the upstream universal exhaust gas oxygen (UEGO) sensor, as mandated by the California air resources board (CARB), is a necessary action to maintain the performance of the operation of the air-fuel ratio (AFR) control system and indicate the need for maintenance when a fault is present which could potentially lead to exceeding the emissions limits. When the UEGO sensor fault is accurately diagnosed, i.e. fault is detected, direction is identified and magnitude is estimated, tuning of the controller gains can be performed accurately with minimal calibration efforts. Presented in this paper is a control strategy that utilizes the type, direction and magnitude of fault detected to adapt the gains of the controller and update the parameters of the Smith predictor (SP) in order to maintain the stability of AFR control loop. The proposed approach has been validated on a vehicle (Mustang V6 3.7L) equipped with ATI No-Hooks rapid prototyping system. Different fault types and magnitudes were tested and the tailpipe emissions were assessed on federal test procedure (FTP) cycles.

Experimental Investigation of Switching Oxygen Sensor Behavior Due to Exhaust Gas Effects

2006 ◽  
Author(s):  
Adam Vosz ◽  
Shawn Midlam-Mohler ◽  
Yann Guezennec ◽  
Steve Yurkovich
Keyword(s):  
Equivalence Ratio ◽  
Oxygen Sensor ◽  
Low Voltage ◽  
Operating Conditions ◽  
Feedback Signal ◽  
Exhaust Gas ◽  
Engine Exhaust ◽  
Switch Point ◽  
Fuel Ratio ◽  
The Impact

Switching type exhaust gas oxygen sensors are critical to the performance of air-to-fuel ratio control in stoichiometric SI engines. Controlling the air-to-fuel ratio around stoichiometry is necessary for adequate three-way catalyst performance to meet government emissions regulations. However, the feedback signal from the sensor does not always truly depict the actual chemical mixture present in the exhaust gasses, which intrinsically affects the catalyst performance. A sensor may not provide correct air-to-fuel ratio feedback due to certain species in the exhaust gas which affect the equivalence ratio that the sensor switches from the high to low voltage or vice versa. This work attempts to characterize the impact of gas on fresh and aged sensors and builds upon earlier work in the field by using real engine exhaust rather simulated exhaust gas. In these experiments, the air-to-fuel ratio of a stoichiometric gasoline engine is incrementally increased from a lean to rich mixture to elicit the full switching response of the oxygen sensor. Additional sensor output curves are generated in the presence of external additive gases such as hydrogen, carbon monoxide, propane, and gasoline vapor. An automotive emissions analyzer and a hydrogen analyzer detect the concentrations of the exhaust gases and the chemical equivalence ratio is calculated using a carbon balance. This equivalence ratio creates a reference to examine the accuracy of the switch point of the sensor to actual stoichiometry. Using these data sets, it is possible to determine observe the effect of various gas species on the air to fuel ratio at which the sensor switches. The sensitivity of the different sensors to gas concentrations are quantified and presented, which form an elementary model to predict the sensor switch point in the presence of these gas species. Primary findings indicate that the impact of species on the sensor switch point is linearly related to the concentration of the species; sensor type and sensor age have an effect on a sensor's sensitivity to species; and different hydrocarbon species affect sensors differently. The findings support the simulated exhaust gas results reported in the literature in that the degree of interference of a species is related to the diffusion rate of the species with respect to oxygen through the sensor. The results also point toward the importance of the species of hydrocarbons in the engine exhaust, which are uncontrolled and can vary with engine operating conditions. This feature is critical to the application of this knowledge to automotive control.

Universal Air-Fuel Ratio Heated Exhaust Gas Oxygen Sensor and Further Applications

1992 ◽  
Author(s):  
Tessho Yamada ◽  
Nobuhiro Hayakawa ◽  
Yoshihide Kami ◽  
Takeishi Kawai
Keyword(s):  
Oxygen Sensor ◽  
Exhaust Gas ◽  
Fuel Ratio

AFR-Based Fuel Ethanol Content Estimation in Flex-Fuel Engines Tolerant to MAF Sensor Drifts

2013 ◽  
Vol 21 (3) ◽  
pp. 590-603 ◽  
Author(s):  
Kyung-ho Ahn ◽  
Anna G. Stefanopoulou ◽  
Mrdjan Jankovic
Keyword(s):  
Fuel Ethanol ◽  
Ethanol Content ◽  
Flex Fuel

scholarly journals Analisis Pengaruh High Pressure Compressor Rotor Clearance Terhadap Exhaus Gas Temperature Margin pada CFM56-7

2021 ◽  
Vol 6 (2) ◽  
pp. 50-55
Author(s):  
Wildan Sofary Darga ◽  
Edy K. Alimin ◽  
Endah Yuniarti
Keyword(s):  
High Pressure ◽  
Engine Performance ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Compressor Rotor ◽  
High Pressure Compressor ◽  
The Difference ◽  
Gas Turbine Exhaust ◽  
Temperature Margin ◽  
Pressure Compressor

Exhaust Gas Temperatue is an parameter where the hot gases’s temperature leave the gas turbine. Exhaust gas temperature margin is the difference between highest temperature at take off phase with redline on indicator (???????????? ???????????????????????? °????=???????????? ????????????????????????????−???????????? ???????????????? ????????????). EGTM is one of any factor to determine engine performance. A good perfomance of an engine when it has a big margin (EGTM), during operation of an engine the EGTM could decrease untill 0 (zero). So many factors could affect EGTM deteroration there are: distress hardware such as airfoil erosion, leak of an airseals, and increase of clearance between tip balde and shroud. Increase of clearance happens in high pressure compressor rotor clearance. In CFM56-7 have 9 stage(s) of high pressure compressor and each stage give the EGT Loses. The calculation of EGT Effect/Losses is actual celarance – minimum clearance x 1000 x EGT Effect °C, where actual clearance define by the substraction of outside diameter’s rotor with inside diameter’s shroud, minimum clearance define in the manual, 1000 is adjustment from mils/microinch to inch, and EGT Effect is temperature that define in the manual. The analysist had done with 6 (six) engine serial number and proceed by corelation that shown linkage between clearance and EGT Effect, the corelation is strong shown the result of corelation (r) is 0.994275999 or nearest 1.

scholarly journals Numerical Analysis of Diesel Engine with Modified Inlet Valve

2019 ◽  
Vol 8 (6) ◽  
pp. 2378-2380
Keyword(s):  
Numerical Analysis ◽  
Combustion Engine ◽  
Air Flow ◽  
Valve Lift ◽  
Intake Manifold ◽  
Compression Ignition Engine ◽  
Inlet Valve ◽  
Complete Combustion ◽  
Single Cylinder ◽  
Flow Motion

The Internal combustion engine is one of the widely used mechanical system. The primary aspect of all types of engines is the amount of power produced which, is affected by the complete combustion of a mixture of air and fuel. The objective of this present work is to outline the improved performance of single-cylinder Compression Ignition engine with the aid of geometrical modifications of Inlet manifold. The Study is performed on Kirlosakr CI engine. For modeling of engine assembly, CATIA V5 Software has been used. The Numerical simulations are performed with Ansys 14.5 and solver used as CFX. In this work, two different engine models such as Conventional valve and Modified valve with plate is being considered for CFD analysis. The simulation study of air flow motion with a valve lift of 4 mm, 6 mm and 8 mm is performed for both valve configurations. This numerical analysis aims to maximize the air velocity in the inlet valve with minimum turbulence which in turn improves the engine performance. The study is performed on the single cylinder four-stroke variable compression ratio diesel engines. In the present study, the air flow motion inside the intake manifold of an engine is simulated and investigations are performed by considering the six conditions of the intake valve. The results obtained acts as a basis for further investigation of a variety of valve geometry.

scholarly journals Studi Penggunaan Variable Speed Drive Untuk Pengaturan Kecepatan Motor Exhaust Fan Pada Dyno Test Room PT. Trakindo Utama Pekanbaru

JURNAL TEKNIK ◽  
2018 ◽  
Vol 12 (2) ◽  
pp. 85-96
Author(s):  
Elham Prasetyo Wibowo ◽  
Elvira Zondra ◽  
Usaha Situmeang
Keyword(s):  
Power Consumption ◽  
Induction Motor ◽  
Gas Flow ◽  
Air Flow ◽  
Load Test ◽  
Exhaust Gas ◽  
Variable Speed ◽  
Variable Speed Drive ◽  
Combustion Gas ◽  
Motor Exhaust

                                                                                                                                      ABSTRAK              Exhaust fan adalah peralatan berupa sudu-sudu yang berputar dan memanfaatkan gaya sentrifugal untuk membuang exhaust gas hasil pembakaran bahan bakar solar engine diesel pada saat dilakukan tes pembebanan penuh. Dengan exhaust fan, gas karbondioksida yang dihasilkan oleh engine diesel memungkinkan untuk dibuang dengan cepat sehingga tidak memenuhi ruangan dan membahayakan bagi setiap karyawan. Pengoperasian exhaust fan dilakukan sesuai jadwal pengetesan engine. Exhaust fan tersebut digerakkan oleh motor induksi 3 phasa 30 kW dengan putaran nominal secara konstan. Pada saat pengetesan engine dengan nilai aliran gas buang yang rendah, exhaust fan tetap dioperasikan dengan kecepatan nominal. Operasional motor exhaust fan dengan kecepatan konstan seperti ini akan mengakibatkan konsumsi daya listrik yang relatif tinggi dari pada motor dengan kecepatan berubah-ubah sesuai kebutuhan. Sebagai pertimbangan hasil perhitungan untuk engine C 18 Caterpillar kapasitas 831 hp yang sebelumya  membutuhkan operasional exhaust fan dengan daya 24,7927 kW nilai sama untuk semua model engine, setelah penggunaan VSD dapat dikurangi sebesar 14,35 %  menjadi 21,2343 kW saja. Penelitian ini bertujuan mendapatkan probabilitas hubungan antara konsumsi energi listrik, frekuensi pada variable speed drive, putaran motor induksi dan nilai aliran udara pada cerobong exhaust fan. Nilai aliran udara exhaust fan tersebut akan disesuaikan dengan nilai aliran gas pembakaran yang dihasilkan oleh engine. Analisa optimasi motor exhaust fan ini sedianya akan menggunakan Matematic Analysis dan simulasi menggunakan simulink matlab sehingga diharapkan ada solusi untuk melakukan penghematan terhadap konsumsi daya motor, kemudian bisa diterapkan dalam semua pengoperasian motor yang ada di perusahaan.   Kata kunci : variable speed drive, motor induksi, exhaust fan                                                                                                                                            ABSTRACT              The exhaust fan is a rotary blade device which produces centrifugal force to remove exhaust gas from diesel fuel combustion during a full load test. With exhaust fans, the carbondioxide gases that generated by the diesel engine allows to be disposed quickly so that it does not fill the room and harm to every employee. The operation of  exhaust fan is carried out according to the engine test schedule. The exhaust fan is driven by a 3 phase induction motor of  30 kW with constant rotation. When testing the engine with a low Exhaust Gas flow value, the exhaust fan remains operated at rated speed. Operational exhaust fan with a constant speed like this will result in relatively high power consumption of the motor with the speed of change as needed. Considering the calculation results for C 18 engine Caterpillar capacity of 831 hp which previously required operational exhaust fan with 24,7927 kW of equal value for all engine models, after the use of VSD can be reduced by 14.35% to 21.2343 kW only. This study aims to obtain the probability of relationship between electrical energy consumption, frequency on the variable speed drive, induction motor rotation and the value of air flow in the exhaust fan chimney. The value of the exhaust fan air flow will be adjusted to the combustion gas flow value generated by the engine. The optimization analysis of this motor exhaust fan will be using Matematic Analysis and simulation using matlab simulink so it is expected there is a solution to make savings to motor power consumption, then it can be applied in all the motor operation in the company.   Keywords: variable speed drive, induction motor, exhaust fan

scholarly journals Learning reference governor for cycle-to-cycle combustion control with misfire avoidance in spark-ignition engines at high exhaust gas recirculation–diluted conditions

2020 ◽  
Vol 21 (10) ◽  
pp. 1819-1834
Author(s):  
Bryan P Maldonado ◽  
Nan Li ◽  
Ilya Kolmanovsky ◽  
Anna G Stefanopoulou
Keyword(s):  
Combustion Process ◽  
Exhaust Gas Recirculation ◽  
Operating Conditions ◽  
Intake Manifold ◽  
Exhaust Gas ◽  
Model Free ◽  
Recirculation Rate ◽  
Valve Position ◽  
Gas Recirculation ◽  
Reference Governor

Cycle-to-cycle feedback control is employed to achieve optimal combustion phasing while maintaining high levels of exhaust gas recirculation by adjusting the spark advance and the exhaust gas recirculation valve position. The control development is based on a control-oriented model that captures the effects of throttle position, exhaust gas recirculation valve position, and spark timing on the combustion phasing. Under the assumption that in-cylinder pressure information is available, an adaptive extended Kalman filter approach is used to estimate the exhaust gas recirculation rate into the intake manifold based on combustion phasing measurements. The estimation algorithm is adaptive since the cycle-to-cycle combustion variability (output covariance) is not known a priori and changes with operating conditions. A linear quadratic regulator controller is designed to maintain optimal combustion phasing while maximizing exhaust gas recirculation levels during load transients coming from throttle tip-in and tip-out commands from the driver. During throttle tip-outs, however, a combination of a high exhaust gas recirculation rate and an overly advanced spark, product of the dynamic response of the system, generates a sequence of misfire events. In this work, an explicit reference governor is used as an add-on scheme to the closed-loop system in order to avoid the violation of the misfire limit. The reference governor is enhanced with model-free learning which enables it to avoid misfires after a learning phase. Experimental results are reported which illustrate the potential of the proposed control strategy for achieving an optimal combustion process during highly diluted conditions for improving fuel efficiency.

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