2004-01-2977 IC Engine Retard Ignition Timing Limit Detection and Control Using In-Cylinder Ionization Signal

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IC Engine Retard Ignition Timing Limit Detection and Control using In-Cylinder Ionization Signal

Ibrahim Haskara, Guoming G. Zhu and Jim Winkelman Visteon Corporation

Reprinted From: SI Engine Experiment and Modeling (SP-1901)

Powertrain & Fluid Systems Conference and Exhibition Tampa, Florida USA October 25-28, 2004

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2004-01-2977 IC Engine Retard Ignition Timing Limit Detection and Control using In-Cylinder Ionization Signal

Ibrahim Haskara, Guoming G. Zhu and Jim Winkelman Visteon Corporation

ABSTRACT through in-cylinder combustion information in order to optimally adjust the operational boundaries. Internal combustion engines are designed to maximize power subject to meeting exhaust emission The use of in-cylinder sensors for combustion control is requirements and minimizing fuel consumption. a promising way of improving the fuel economy, power However, the usable range of ignition timing is often output and emissions of production vehicles (see limited by knock in the advance direction and by 4,5,6,7,8 and the references cited therein among combustion instability (partial burn and misfire) in the others). In this paper, in-cylinder ionization signals are retard direction. This paper details a retard limit studied to determine a combustion stability metric for management system utilizing ionization signals in order ignition retard limit. Spark sweeps are conducted at to maintain the desired combustion quality and prevent different operating points. Stochastic properties (mean, the occurrence of misfire without using fixed limits. In- variance and probability distribution functions) of peak cylinder ionization signals are processed to derive a ionization location and the ionization energy content metric for combustion quality and closeness of distribution are correlated to the combustion quality combustion to partial burn/misfire limit, which is used to (COVariance of Indicated Mean Effective Pressure provide a limiting value for the baseline ignition timing in IMEP) and combustion type (normal, late but complete, the retard direction. For normal operations, this assures incomplete and misfire). A feedback parameter is that the combustion variability is kept within an derived from the ionization signal as an indicator of the acceptable range. During start-up operations, the retard closeness to the retard limit. Pressure measurements limit management can be used as a rapid catalyst light- are used to confirm information for these correlations. off strategy by maximally delaying the combustion as The data is then used to generate stochastic relations long as misfire and partial-burn are avoided. This from ignition timing to the processed ionization improved start-up strategy reduces cold-start HC parameter at different operating conditions. emissions by reducing the time required to increase the catalysts temperature to its light-off level. The closed A stochastic ignition retard limit control utilizing the loop nature of the system provides maximum usage of derived retard limit ionization parameter is also proposed the possible ignition timing range in the retard direction in the paper. Experimental data from dynamometer tests at any given operating condition. is included to demonstrate that the controller can limit and correct the ignition timing to keep the combustion INTRODUCTION quality/stability from exceeding a user-specified level. It is further shown that the control system is able to In a conventional spark-ignition (SI) engine, combustion operate the engine at its retard limit despite the cycle-to- is initiated at the spark plug by an electrical discharge. cycle combustion variability and inherent ionization Recent advances in the powertrain electronic controls signal variations owing to that stochastic nature. make it possible to employ online spark adjustment to optimize the engine operation in terms of power, fuel RETARD LIMIT MANAGEMENT economy and emissions. However, the range of ignition timing one would like to use is often limited by knock in )RUDFORVHGORRSLJQLWLRQFRQWUROV\VWHPWKHEHQHILWRI the advance direction and by combustion instability D FRPEXVWLRQ UHWDUG LQGLFDWRU LV WZRIROG 'XULQJQRUPDO (partial burn and misfire) in the retard direction. Since RSHUDWLQJ FRQGLWLRQV LI WKH EDVHOLQH LJQLWLRQ VWUDWHJ\ the feasible ignition timing range depends on the engine WHQGV WR SXVK WKH LJQLWLRQ WLPLQJ WR D OHYHO ZKHUH WKH operating conditions, it is beneficial to extract this online FRPEXVWLRQ YDULDELOLW\ LV QRW DFFHSWDEOH LJQLWLRQWLPLQJ Downloaded from SAE International by Brought To You Michigan State Univ, Thursday, April 02, 2015

FDQ EH OLPLWHG LQ WKH UHWDUG GLUHFWLRQ 6HFRQGO\ VLQFH ignition timing is too early (advanced), useful combustion WKLVUHWDUGOLPLWLVFRQWLQXDOO\DGMXVWHGE\PRQLWRULQJWKH work is wasted during the compression stroke. On the FRPEXVWLRQ WKURXJK WKH LQF\OLQGHU LRQL]DWLRQ VLJQDOV other hand, if the combustion process starts too late GLIIHUHQW FULWHULD FDQ VWLOO EH LQFOXGHG DQG RSWLPL]HG (retard), the peak pressure occurs later in the expansion RQOLQH WR GHWHUPLQH WKH ILQDO WLPLQJ LQVWHDG RI XVLQJ D stroke and its resulting torque diminishes. The optimum RQHILWVDOOOLPLWYDOXHRUPDS spark, for which the maximum brake torque is obtained in the presence of these opposing trends, is called MBT During engine warm-up, the retard limit management timing. Maximum brake power and minimum brake can seek the maximum retard possible while assuring specific fuel consumption are also achieved with MBT that misfire is avoided with the objective of increasing timing. A typical cylinder pressure behavior during a the catalyst temperature rapidly. Delaying the spark sweep is shown in Figure 2. This data was combustion through high values of ignition retard can gathered from a 3L, 6-cylinder engine operated in an shorten the time that it takes the catalyst to reach its engine dyno. Spark timing was swept from 37 oBTDC to light-off temperature. Therefore, the conventional three- 25 oATDC at 1500 RPM and 2.5 bar BMEP for MBT way catalyst becomes effective much sooner in reducing spark. For each spark, the plotted pressure signal is the tail-pipe emissions (1, 2, 3). However, if the ignition average of 300 consecutive cycles. retard is too much, engine-out HC emissions become excessive due to incomplete combustion as well as misfire. An open loop retard calibration needs to provide enough margins to avoid misfire at all conditions and with all types of fuels. It therefore is inherently conservative. On the other hand, a real time retard limit indicator as part of a closed loop strategy alleviates this conservatism by further being able to push the timing in the retard direction if things are favorable. That way, the catalyst light-off time is minimized and the tail-pipe emissions can be reduced.

The architecture of a stochastic retard limit management system is shown in Figure 1.

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'ZHOO ,JQLWLRQ 6WRFKDVWLF 3&0,JQLWLRQ &0' &RQWURO 5HWDUG/LPLW &RQWURO 6LJQDO &RQWURO As shown in Figure 3, the combustion torque peaks at a 6WUDWHJ\ *HQHUDWLRQ spark around 29 oBTDC (indicating the MBT timing for this operating point) and starts falling when the spark is further retarded. )LJXUH&ORVHGORRSUHWDUGOLPLWFRQWUROV\VWHP The covariance of IMEP is also included in Figure 4 as a DUFKLWHFWXUH measure of combustion quality. As a practical The ignition coil in this system is both a sensor and an convention, a covariance value around 3% is regarded actuator. As a sensor, it has one ionization output signal. as an indication of good quality combustion. For this As an actuator it has one dwell control input signal for operating point, ignition timing should be kept before 17 ignition. The ionization feedback signals of all cylinders oBTDC in order to maintain the covariance below 3%. are fed into the signal conditioning circuit, and signals The covariance goes beyond 5% with an ignition timing are merged. The conditioning signal is then sampled and of 11oBTDC. As the ignition is retarded beyond that processed to determine a retard limit indicator, as it will value, the combustion variations and roughness further be outlined in the following sections. The further details increase. Before that, the combustion can be of the set-up can also be found in 5,6 and 7. categorized as normal. When the ignition timing is delayed, combustion starts to take place later in the COMBUSTION BEHAVIOR WITH IGNITION expansion stroke but initially can still be completed RETARD before the exhaust valves are opened (late but complete). With further retard, the allotted duration For a spark-ignition (SI) engine, as ignition timing is becomes too small for the combustion to be completed varied relative to TDC (top dead center), the cylinder and the combustion further extends to the exhaust pressure, and in turn, combustion torque varies. If the stroke (incomplete). Eventually, for some cycles, Downloaded from SAE International by Brought To You Michigan State Univ, Thursday, April 02, 2015 combustion does not grow at all and the cylinder other hand, for the cycle of Figure 6, the combustion contents go to the exhaust manifold directly (misfire). duration is longer compared to that of Figure 5 based on its burn profile. However, the burning still ends much before the exhaust valves are opened. Therefore, the combustion is late but still complete. The ionization signal is a bit noisier than that of the Figure 5, but that itself could not be a robust indicator of the lateness of the combustion. It is also important to note that there is no distinctive thermal and chemical ionization peaks this time. Instead, the thermal peak is folded into the chemical ionization region. However, the strength of ionization signal (peak magnitude and area) is even more for the late combustion case. Therefore, there is not a clear correlation between the strength of ionization and its torque output either. Figure 7 with a spark of 5 oATDC depicts a cycle with incomplete combustion. Ionization signal extends well beyond the exhaust stroke. Similarly, burn profile extends towards the exhaust stroke as well. However, the ionization signal is very wide and tails down over a long crank interval.

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In summary, the following observations can be made as Figure 5-Figure 7 show a typical ionization current and the behavior of ionization signal with varied ignition the corresponding burn profiles from a sample timing: combustion cycle at three spark timings: 21 oBTDC, 11 o o BTDC and 5 ATDC at the same speed and throttle x For normal combustions, the ionization signal position. For burn profile, the pressure signal is used to has a typical shape with two distinctive peaks compute the mass fraction burned from a heat release after the spark charging duration. While the model. Note that, for the cycle of Figure 5, the ignition is being retarded, these two peaks combustion is normal and the ionization signal has merge and the signal shows a single peak distinct chemical and thermal ionization regions. The shape with a tapering falling edge. thermal ionization is less noticeable as it is usually the case with light load conditions. Note that, there is no The ionization signal becomes wider as the o x significant ionization signal beyond roughly 50 ATDC. spark is retarded. However, relative values of This coincides with the burn profile, from which no the signal or its total area/energy (square area) further burning is noticeable beyond that location. On the do not have correlations with the amount of Downloaded from SAE International by Brought To You Michigan State Univ, Thursday, April 02, 2015

ignition retard. On the other hand, a distribution For normal combustions, the peak location does measure such as the location at which the first not go much beyond TDC. Furthermore, the first 90% of the total area under ionization signal has peak location in crank angle coordinates been achieved is a good indicator. This is referenced to the end of spark event increases because the range that the ionization signal rapidly when the combustion starts leaving the extends is affected by the ignition timing. normal range.

RETARD LIMIT INDICATORS FROM IONIZATION SIGNAL

Based on the previous observations, two retard limit indicators (peak location and distribution location) from ionization signal are proposed and studied in this section A typical ionization signal is shown in Figure 8. The peak location is defined as the crank angle at which the chemical-ionization part of the ion signal takes its maximum value. In other words, it is when the ionization signal peaks out first after the spark charging window. The ionization signal is also integrated over a user- specified window and the crank angle at which the ion integral reaches a calibratable percentage of the total area is determined. This parameter is defined as the distribution location. The normalized ion integral is also shown in Figure 8. It is further possible to use the integral of the square (energy) in this computation )LJXUH%XUQSURILOHDQGLRQVLJQDOVDW67 R%7'& instead. The resulting area/energy signal is normalized relative to the total area/energy. Note that, 100% distribution location is ideally reached when the ionization signal completely dies-out. Similarly, X% distribution location is the crank degree for which the normalized ion integral is X/100. A percentage close to 100 is used to approximately locate the crank location after which the ionization signal strength (combustion activity) is minimal.

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x At the ultimate case, the location at which the ionization signal dies out also indicates how much the combustion is really retarded. For example, there is still significant ionization signal in Figure 7 even after the exhaust valves are opened (124 oATDC for this particular engine )LJXUH5HWDUGOLPLWLQGLFDWRUVIURPWKHLRQL]DWLRQVLJQDO and valve timing), which points out some combustion activity going on at the exhaust Figure 9-Figure 11 show the stochastic properties of the stroke. ion peak location at spark timings 21 oBTDC, 11 oBTDC and 5 oATDC, respectively. At each firing event, the x The first peak location of ionization signal can ionization signal is processed to obtain the peak location also be correlated to the amount of spark retard. number for that particular combustion. For each case, Downloaded from SAE International by Brought To You Michigan State Univ, Thursday, April 02, 2015

300 cycles (number of consecutive firing events at the a number of cycles increase rapidly with the retard. same conditions) of data are used to create the PDF Thus regulating the statistics of the ionization signal, not (probability density function) or histogram of the peak ion each individual cycle, will also control the combustion signal location. The PDFs of distribution location quality. Another observation is that for a normal parameter are also quite similar to those of peak location combustion (Figure 9), the peak location displays a and therefore not included here for brevity. Gaussian (normal) distribution. When the ignition is retarded, the PDF of peak location starts skewing towards the retard direction (Figure 10). Note that the misfire/partial burn cycles are the primary interest and they are the ones extending in the retard direction. Therefore, a derived parameter from PDF, such as the worst-case data (highest peak location) in the buffer or among a percentage of it when the data are sorted from most advanced (lowest peak location) to most retard (highest peak location) is superior to using variance information itself in capturing these limiting cycles. This point is later going to be utilized in the control strategy development.

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Based on the PDFs, the cycle-to-cycle variability of combustion and the statistics of the ionization signals seem to be coupled. However, the relation is in terms of their stochastic properties rather than being a cycle-to- cycle correspondence. For example, a peak location value of 10 oATDC can be seen in both Figure 9 and Figure 10, but it’s most probable to have this value with a spark timing of 11 oBTDC among the three plots included. Similarly, a peak location value close to 60 oATDC has been observed only in one cycle in Figure 10 while that number was almost the mean value of all data in Figure 11. In other words, peak location from a single )LJXUH:RUVWFDVHLRQSHDNORFDWLRQGXULQJVSDUNVZHHS cycle may not be that informative. However, both the mean and the standard deviation of peak location along Downloaded from SAE International by Brought To You Michigan State Univ, Thursday, April 02, 2015

Figure 12-Figure 15 show the stochastic properties of The desired values for these parameters need to be the introduced ionization retard limit parameters during a calibrated to the engine operating points. A mean value spark sweep at 1500 RPM and 2.5 bar BMEP at MBT of 5 oATDC for peak location appeared to be sufficient spark. For distribution location, the location where 95% for good combustion quality for a variety of operating of ionization signal area occurs was used. Both the points. The PDF of a signal such as the worst-case peak worst-case ion peak location and distribution location are location can further be used to adapt this target online calculated with respect two references: one with respect based on the achieved performance (second order to the TDC location and the other with respect to the statistics). This simplifies the calibration task. On the spark timing, as shown in Figure 12 and Figure 14. The other hand, for cold-start the worst-case distribution mean value of each parameter increases as the timing is location should be properly placed before the exhaust moved in the retard direction, demonstrating consistent valve opening angle. gradient (or slope).

Note that, the worst-case peak location (the maximum peak location among 300 cycles) and mean value with respect to ignition timing, the duration from ignition timing crank location to the peak location, was almost flat for the first 4-5 ignition timings (Figure 12 and Figure 13). After that, there is a sharp increase in the parameters with further ignition retard. This observation is in accordance with Figure 4, for which the combustion quality is affected beyond a spark timing of 11 oBTDC. The standard deviation of peak location in Figure 13 also shows an abrupt increase after that timing. Based on Figure 14, ignition timing of 5 oBTDC, the worst-case ionization signal distribution location (largest number among 300 cycles) was before roughly 100 oATDC, which basically indicates that the combustion is still complete at that ignition timing although it’s late. )LJXUH:RUVWFDVHLRQGLVWULEXWLRQORFDWLRQ

Next a retard limit management control system is discussed. This system computes the introduced parameters from the measured ionization signal at each cycle and derives the stochastic properties of the data online from a stored buffer. Based on these online feedback signals, the control provides a closed loop limit value for the ignition timing in the retard direction.

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This analysis has been performed at different speed /load conditions and the general trend hold at all conditions. Basically, the mean value of peak/distribution location can be used as the feedback signal for regulation (first order statistics). It has been observed that the peak location shows a better correlation when the ignition retard is not too extensive (which is the case when around MBT) whereas the distribution location )LJXUH,RQGLVWULEXWLRQORFDWLRQVWDWLVWLFV shows a better correlation when the retard level is significant (this is the case for example at cold start). Downloaded from SAE International by Brought To You Michigan State Univ, Thursday, April 02, 2015

RETARD LIMIT CONTROL provide the desired settling time and steady-state accuracy for the response. Figure 16 shows the stochastic closed-loop retard limit controller. It's a part of an overall spark controller, which Adaptive seeking feedback: The purpose of this loop is manages the spark timing for best fuel economy, power two-fold: reducing the calibration conservativeness of and emissions by employing a closed loop MBT timing providing the engine with its "TRUE" retard limit target strategy (7). The ionization signal from each cylinder is and improving robustness of retard limit controller when sampled and saved in a buffer at each combustion the engine operates under different conditions. This is event. The overall spark control is triggered at every accomplished by using an error signal between the firing event and retard limit control processes the desired confidence level target and the achieved. Note ionization signal from the most recent cycle to compute that the confidence level is a second-order property of the retard limit feedback parameters. The objective of PDF like variance. The adaptive seeking algorithm retard limit controller is to provide a retard limit for the reduces the mean target for the regulation controller if overall spark controller to assure combustion stability. the confidence number is greater than the specified; otherwise, increases the mean target value. The key part of the retard controller is the stochastic analyzer block. The derived ionization parameters from Instant correction feedback: This block calculates an each firing cycle are gathered in a buffer of a user- instant correction signal to be fed into the integration selected size for stochastic analysis of the data. portion of PI controller. When the error between Basically, the mean, standard deviation and PDF of data confidence level target and retard limit feedback is are constantly updated at the end of each firing event. greater than zero, the output is zero. That is, no Using the PDF, an achieved user-specified percentage correction is required, and when the error is less than confidence level number is also computed. This number zero, the error is fed into a one dimensional lookup table (crank location) is defined as follows: saying 90% that outputs an instant correction in the advanced confidence number for peak location is 20 degrees direction for the integration portion of the PI controller. means that for the 90% of the combustion events in the buffer, the measured peak locations are more advanced With these three loops: the ideal action of the retard limit than that particular location, 20 oATDC. controller can be explained as follows: Suppose that we want to make sure that the ionization peak location will Three main feedback actions are proposed in the not go beyond 20 oATDC. This location is then the stochastic retard limit controller. Their functionalities are desired confidence level target. Using the standard listed below: deviation of the measured data, one can back-calculate a nominal target for the regulation controller by subtracting a certain multiple of the standard deviation of

(QJLQH6SHHG/RDG %DVHOLQH the measured data in the buffer. That initial mean target ,J QLWLRQ7LPLQJ is then increased by the adaptive seeking loop slowly if &RQILGHQFH 0HDQWDUJHW OHYHOWDUJHW YD OX H 6DWXUDWLRQ )HHGIRUZDUG the resulting, say 90% confidence level number PDQDJHPHQW computed from the measured data is less than desired o $GDSWLYH 3, )LQDO $GDSWLYH &RQWUROOHU ,JQLWLRQ confidence level target of 20 ATDC. That way, if the

6HHNLQJ VHHNLQJORRS 6WRFKDVWLF $OJRULWKP FRQWUROORRS 7LPLQJ initial mean target was too conservative; i.e., the worst- $GDSWDWLRQHUURU 3 &RQWURO o case peak location is well below 20 ATDC, then the &RQILGHQFHOHYHO DFKLHYHG 5HWDUGOLPLW mean target will be increased. On the other hand, the IHHGEDFN 6WRFKDVWLF DQDO\]HU 0HDQ 5HJXODWLRQ instant correction feedback acts as a safety since DFKLHYHG , &RQWURO FRQWUROOHU o whenever the feedback goes beyond 20 ATDC it will ,QVWDQW ,QVWDQW &RUUHFWLRQ0DS instantaneously advance the retard limit. Then the FRUUHFWLRQORRS seeking will start again to push the retard limit as long as the things are favorable. Since the mean and stochastic )LJXUH6WRFKDVWLFFORVHGORRSUHWDUGOLPLWFRQWUROOHU properties are used as feedback signals, the controller will not react aggressively to each combustion variation, which would be the case if the feedback signals from each cycle were used directly. Regulation controller: The regulation loop is used to regulate the mean value of the retard limit feedback The interaction of the retard limit controller with the (peak location or distribution location) to a mean target overall spark controller is as follows: If the baseline value. The regulation controller is structured as a PI spark is more advanced than the current retard limit, controller with an additional sliding mode control term then the baseline spark is used as it is. In that case, the and a feed-forward term based on engine operating retard limit controller pushes the limit in the maximum conditions. Despite the variability of the retard limit retard direction by itself. This is because the integration feedback, its mean value is a well-behaved signal for will keep integrating till the maximum retard allowed is regulation purposes. The regulation controller is tuned to reached (an anti-windup scheme is used) as it was Downloaded from SAE International by Brought To You Michigan State Univ, Thursday, April 02, 2015 designed. If the baseline spark controller pushes the exhaust valves were opened and the controlled high ignition timing to a level at which the feedback signals retard was safe in terms of engine-out HC emissions. generate corrections, then the retard limit moves from its Figure 20 demonstrates the corresponding fast exhaust maximum limit to a new level as a variable saturation temperature rise-up during the run. An open loop limit on the baseline spark. On the other hand, if the temperature profile was also included in Figure 20 to baseline controller still tends to push the spark in the show the improved temperature rise-time with the retard direction, the seeking and instant correction control. For the open loop case, the ignition timing was actions of the retard controller will adjust the retard limit held at TDC, which was the initial ignition timing for the online. closed loop controller. Based on Figure 20, the time it takes the exhaust temperature to reach 500 C was To illustrate the performance of the retard limit reduced to 12 seconds from 17 seconds with the closed controller, some preliminary results from dyno runs have loop controller. been included in Figure 17-Figure 20. The stochastic analyzer block and the regulation/adaptive seeking loops were tested at several fixed operating points. The main emphasis so far was given to the evaluation of the control features rather than demonstrating its projected benefits. A 3L, 6-cylinder engine equipped with ionization feedback coils was used for these experiments. Due to our current dyno set-up, the experiments were run at a constant MAP (manifold absolute pressure) with fixed throttle openings, rather than fixing load. Therefore, a fixed engine load cannot be maintained during a spark retard. Although this may not be the case for real operations, it is considered to be sufficient for control algorithm evaluations.

Figure 17 and Figure 18 demonstrate the controllability of the combustion through the proposed controller. In Figure 17, first the mean ion peak location was regulated to 10 oATDC to show the regulation performance of the retard limit controller. Around 50 seconds, the adaptive seeking is enabled with the goal of bringing the )LJXUH5HWDUGOLPLWFRQWURO &DVH confidence level to 30 oATDC. Note that the mean target is adapted to drive ignition to a new level at which the confidence level is in the vicinity of 30 oATDC as desired. In Figure 18, the system is started at a retarded ignition timing, which results in high combustion variability. From correlations, it has been observed that the ion peak location should be located before roughly 5-10 oATDC to assure a good combustion quality. To this end, the retard limit controller was activated to regulate the mean value of ion peak location to 10 oATDC as an initial mean target. At the resulting ignition timing, the confidence level was about 17 oATDC. Around 60 seconds, the adaptive seeking loop was enabled to bring the confidence level to 10 oATDC this time. At the new spark level, the covariance of IMEP reduces to below 3% at the steady state.

Figure 19-Figure 20 show responses from a cold-start run. For that, the ionization distribution location parameter was used as the feedback signal and the control was activated with all features to drive the )LJXUH5HWDUGOLPLWFRQWURO &DVH confidence level to 110 oATDC. The confidence level was also included in Figure 19 as a performance measure. Note that it was kept around 110 oATDC at the steady state and did not exceed 124 oATDC, which was the exhaust valve opening timing for the particular engine. Therefore, the combustion was over before the Downloaded from SAE International by Brought To You Michigan State Univ, Thursday, April 02, 2015

REFERENCES

1. N. A. Henein and M. K. Tagomari, Cold-start Hydrocarbon Emissions in Port-Injected Gasoline Engines, Progress in Energy and Combustion Science, 25, pp. 563-593, 1999. 2. J. Zhu and S. C. Chan, An approach for rapid automotive catalyst light off by high values of ignition retard, Journal of the Institute of Energy, pp. 167- 173, 1996. 3. P. Tunestal, M. Wilcutts, A. T. Lee and J. K. Hedrick, In–Cylinder Measurement for Engine Cold- Start Control, Proceedings of the 1999 IEEE International Conference on Control Applications, pp. 460-464, 1999. 4. R. Isermann and N. Muller, Design of Computer Controlled Combustion Engines, Mechatronics, pp. )LJXUH&RQWUROIRUFROGVWDUWUXQXS 1067-1089, 2003. 5. Guoming G. Zhu, Chao F. Daniels and Jim Winkelman, MBT Timing Detection and its Closed- loop Control Using In-Cylinder Pressure Signal, SAE 2003-01-3266, 2003. 6. Chao F. Daniels, Guoming G. Zhu and Jim Winkelman, Inaudible Knock and Partial Burn Detection Using In-Cylinder Ionization Signal, SAE 2003-01-3149, 2003. 7. Guoming G. Zhu, Chao F. Daniels and Jim Winkelman, MBT Timing Detection and its Closed- loop Control Using In-Cylinder Ionization Signal, Submitted to SAE Powertrain and Fluid Systems Conference, Tampa, FL, 2004. 8. Lars Eriksson, Spark advance modeling and control, Ph.D. Dissertation, Linkoping University, 1999. 9. J. B. Heywood, Internal Combustion Engine Fundamentals, McGraw-Hill, 1988. )LJXUH7HPSHUDWXUHYHUVXVFRQWUROOHGLJQLWLRQUHWDUG CONTACT

Ibrahim Haskara, Visteon Corporation, 17000 Rotunda CONCLUSION Drive B-360-172, Dearborn, MI 48185. E-mail: [email protected]. $ VWRFKDVWLF FORVHG ORRS UHWDUG OLPLW PDQDJHPHQW V\VWHPLVSURSRVHGLQWKLVSDSHU7KHV\VWHPLQFOXGHVD UHWDUG OLPLW IHHGEDFN FRPSXWDWLRQPHWKRGGHULYHGIURP DEFINITIONS, ACRONYMS, ABBREVIATIONS LQF\OLQGHU LRQL]DWLRQ VLJQDOV DQG D PXOWLORRS FORVHG ORRS FRQWURO PHWKRG 7KH SURSRVHG FRQWURO V\VWHP FDQ MBT: Minimum spark advance for Best Torque VHHNPDLQWDLQDQGOLPLWWKHLJQLWLRQWLPLQJDWDGHVLUHG TDC: Top Dead Center o XVHUVSHFLILHG OHYHO RI FRPEXVWLRQ TXDOLW\ XVLQJ DQ LRQ ATDC: Degrees After Top Dead Center FXUUHQW VLJQDO 7KH V\VWHP LV FXUUHQWO\ EHLQJ HYDOXDWHG oBTDC: Degrees Before Top Dead Center LQ WHUPV RI LWV SURMHFWHG EHQHILWVRQFRPEXVWLRQTXDOLW\ BMEP: Brake Mean Effective Pressure DQGVWDUWXSHPLVVLRQV IMEP: Indicated Mean Effective Pressure EGR: Exhaust Gas Recirculation SI: Spark Ignition PDF: Probability Distribution Function HC: Hydrocarbons PI: Proportional and Integral MAP: Manifold Absolute Pressure