Engine Torque Nonuniformity Evaluation Using Instantaneous Crankshaft Speed Signal

2003 ◽  
Vol 125 (4) ◽  
pp. 1050-1058 ◽  
Author(s):  
N. Cavina ◽  
F. Ponti

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.

Author(s):  
Nicolò Cavina ◽  
Fabrizio Ponti

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.


Author(s):  
Gian Marco Bianchi ◽  
Piero Pelloni ◽  
Giovanni Osbat ◽  
Marco Parotto ◽  
Rita Di Gioia ◽  
...  

Upcoming Euro 4 and Euro 5 emission standards are increasing efforts on injection system developments in order to improve mixture quality and combustion efficiency. The target features of advanced injection system are related to their capability of operating multiple injection with a precise control of amount of fuel injected, low cycle-by-cycle variability and life drift, within flexible strategies. In order to accomplish this task, performance must be optimised since injection system concept development by acting on. The extensive use of numerical approach has been identified as a necessary integration to experiments in order to put on the market high quality injection system accomplishing strict engine control strategies. The modelling approach allows focusing the experimental campaign only on critical issues saving time and costs, furthermore it is possible to deeply understand inner phenomena that cannot be measured. The lump/ID model of the whole system built into the AMESim® code was presented in previous works: particular attention was devoted in the simulation of the electromagnetic circuits, actual fluid-dynamic forces acting on needle surfaces and discharge coefficients, evaluated by means 3D-CFD simulations. In order to assess new injection system dynamic response under multiple injection strategies reproducing actual engine operating conditions it is necessary to find to proper model settings. In this work the integration between the injector and the system model, which comprehends the pump, the pressure regulator, the rail and the connecting-pipes, will be presented. For reproducing the dynamic response of he whole system will be followed a step-by-step approach in order to prevent modelling inaccuracies. Firstly will be presented the linear analysis results performed in order to find injection system own natural frequencies. Secondly based on linear analysis results will be found proper injection system model settings for predicting dynamic response to external excitations, such as pump perturbations, pressure regulator dynamics and injection pulses. Thirdly experimental results in terms of instantaneous flow rate and integrated injected volume for different operating conditions will be presented in order to highlight the capability of the modelling methodology in addressing the new injection system design.


Author(s):  
Enrico Corti ◽  
Davide Moro

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.


Author(s):  
M. E. Leustek ◽  
C. Sethu ◽  
S. Bohac ◽  
Z. Filipi ◽  
D. Assanis

The instantaneous IMEP method is used to measure crank-angle resolved in-cylinder friction force in a series production spark ignition engine as a function of design parameters and operating conditions. An improved telemetry system, which continues to provide data after 50+ hours of operation at speeds as high as 2000 rpm, is presented. Primary sources of error associated with the technique will be presented. These include intra-cycle engine speed fluctuations, the effect of thermal shock on pressure transducers, the effect of connecting rod force calibration and measurement error. The instantaneous IMEP method is used to measure crank-angle resolved in-cylinder engine friction as functions of engine speed and coolant (oil-film) temperature. Both crank-angle resolved and cycle-integrated results are compared.


Author(s):  
Giuseppe Cantore ◽  
Luca Montorsi ◽  
Fabian Mauss ◽  
Per Amne´us ◽  
Olof Erlandsson ◽  
...  

When analyzing HCCI combustion engine behavior, the integration of experimental tests and numerical simulations is crucial. Investigations of possible engine control strategies as a function of the different operating conditions have to take the behavior of the whole HCCI engine into account, including the effects both of the combustion process and of complex devices. Therefore the numerical simulation code must be able both to model accurately the gas-dynamic of the system and to evaluate the combustion chemical kinetics. This paper focuses on the coupling between the commercial one-dimensional fluid-dynamic GT-Power Code and our in-house detailed chemical kinetic Ignition Code. An interface has been developed in order to exchange information between the two codes: the Ignition Code considers as boundary conditions the GT-Power Code values provided for the gas composition at IVC and the pressure and temperature at every time step and passes back to GT-Power the burnt fuel fraction and stores in an external file the in cylinder gas composition. Thus the whole engine cycle can be accurately simulated, estimating the interactions between the gas-dynamics phenomena along the intake and exhaust pipes and through the valves, and the chemical processes occurring during the closed valves period. This tool makes it possible to analyze the engine behavior under duty cycle operating conditions, and therefore it represents a useful support to the experimental measurements, reducing the number of tests required to assess the proper engine control strategies.


2002 ◽  
Vol 7 (1) ◽  
pp. 135-150 ◽  
Author(s):  
D. N. Malkhede ◽  
H. C. Dhariwal ◽  
M. C. Joshi

In a diesel engine, governor is indispensable for ensuring that the engine maintains a certain speed under various load conditions, that the engine speed does not exceed a certain speed as a protection against self‐destruction or stall. Also, speed fluctuations resulting from poor governing, lead to vibrations, noise, wear and tear and increased level of soot. Therefore it is desirable to have minimum speed fluctuations under all engine‐operating conditions. Inspite of many limitations, most of the existing engines still use simple mechanical governor providing proportional control only. Electronic governors can provide a more flexible P (proportional), I (integral), and D (derivative) control under all speeds and loads. So far no work is reported on optimizing the controller parameters using the analytical approach. In the present work turbo charged diesel engine is analytically modeled based on Krutov's approach for the control analysis. Attempts have been made to optimize controller parameters. The criterion for minimizing the engine speed fluctuations is met by minimizing the Integral Squared Error in engine speed. The parameters obtained have been used to study the engine speed response. The results have shown remarkable improvement in the engine speed fluctuations.


Author(s):  
Zhanming Ding ◽  
Weilin Zhuge ◽  
Yangjun Zhang ◽  
Yong Yin ◽  
Shuyong Zhang

Waste heat recovery (WHR) is one of the main approaches to improve the internal combustion engine (ICE) overall efficiency and reduce emissions. The electric turbocompounding (ETC) technology is considered as a promising WHR technology for vehicle engines due to its compactness and light weight. In order to improve the overall fuel efficiency of the engine at practical operating conditions, the impacts of the implementation of the ETC system should be investigated not only at engine full load conditions, but also under practical driving cycles. In this paper, an ETC system was designed for a 4.75 L diesel engine, in which a power turbine was installed down-stream to the turbocharger turbine. A performance simulation model of the ETC engine was developed on the basis of the diesel engine model, which was validated against engine performance experimental data. The control strategies of the wastegate of turbocharger turbine, the wastegate of power turbine and the operating torque of generator were determined. The relative variation in BSFC was studied under full range of operating conditions, and results show that the maximum improvement of fuel economy is 6.7% at an engine speed of 1000 rpm and 70% of full load, in comparison with the baseline diesel engine. Main factors lead to the performance differences between the ETC engine and the baseline engine were analyzed. Furthermore, the performance of the ETC engine under the C-WTVC driving cycle was investigated. Results show that the implementation of the ETC system resulted in a 1.2% fuel consumption reduction under the C-WTVC driving cycle.


2021 ◽  
Vol 264 ◽  
pp. 05033
Author(s):  
Umidulla Abdurazzokov ◽  
Bakhramjan Sattivaldiev ◽  
Ravshan Khikmatov ◽  
Shakhnoza Ziyaeva

In operation conditions, the transport work of a vehicle is estimated by the increment in the mass of the freight over the distance traveled. This criterion does not characterize the mechanical work of the vehicle in the transport process. Without analyzing the energy costs of performing mechanical work, it is impossible to assess the energy efficiency of a vehicle. The energy efficiency of a vehicle is defined as the ratio of the mechanical work performed by the vehicle to the potential energy of the source. In this paper, it is proposed to determine the engine torque by fuel consumption. The engine torque value depends on the energy required for driving the vehicle. Based on the analysis of the results of computational and experimental studies, a method for assessing the energy efficiency of a vehicle with an internal combustion engine is proposed. The reliability of the results obtained is substantiated by the test results and the available information in practice.


2020 ◽  
Vol 197 ◽  
pp. 06022
Author(s):  
Fabio Fatigati ◽  
Marco Di Bartolomeo ◽  
Giuseppe Lo Biundo ◽  
Francesco Pallante ◽  
Roberto Cipollone

To date, Sliding Vane Pump (SVP) technology is one of the most attractive solution in different technical applications thanks to its reliability and compactness and capability to keep a high efficiency even when it is working far from rated condition. In particular, this feature makes the SVP suitable to be employed for the oil circulation (SVOP) in Internal Combustion Engine (ICE) which is characterized by a wide oil flow rates variation, delivered pressure and temperature variation which causes operating conditions of the pump far from the design point. Flow delivered changes in these machines are produced by varying the eccentricity for a mechanical connection with the engine - or by varying the speed of revolution. The mild hybridization of the powertrains calls for a strong development of electrically assisted engine auxiliaries which undoubtedly makes the flow variations easier to be done, but the presence of an electric motor requires some technological choices not fully assessed, a cost increase and a reliability decrease. The paper presents a mathematical model of a SVOP for oil circulation in ICE, suitably validated by a wide experimental activity. The model integrates a mono and zero-dimensional fluid-dynamic analysis and allows to represent the intimate behaviour of the machine. Moreover, it was employed as virtual platform to discuss pros and cons of different flow rate variation strategies and their effect on the efficiency of the SVOP.


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