Study Of Knock Phenomenon Predicted Bywave 7

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Analysis of the knock model in Ricardo Wave Engine Simulation Software. An excellent study to obtain optimum knock in a gasoline V-8 engine.

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Study Of Knock Phenomenon Predicted Bywave 7

  1. 1. STUDY OF KNOCK PHENOMENON PREDICTED BY WAVE 7.1 PRESENTED To Dr J.NOVAK BY ANUPAM DHYANI
  2. 2. What is KNOCK & how does WAVE take it ? <ul><li>The instantaneous combustion of end gases in a cylinder resulting in a very intense pressure wave that produces the audible, high-frequency ( pinging ) sound is known as SPARK KNOCK </li></ul><ul><li>Besides sound, spark knock can result in pitting , or erosion, of the combustion chamber, damage to spark plug electrodes , and possible structural damage to the engine. Spark knock also leads to loss of engine efficiency </li></ul><ul><li>WAVE TREATS IT AS : </li></ul><ul><li>UNBURNT MASS </li></ul><ul><li>KNOCK INTENSITY = -------------------------- </li></ul><ul><li>TOTAL CYLINDER MASS. </li></ul>
  3. 3. Test Engine specifications and Diagram: <ul><li>Naturally Aspirated Gasoline V8 </li></ul><ul><li>Peak Torque 400 Nm @ 3500 RPM </li></ul><ul><li>BSFC at Peak Eff. 231 g/kWh  </li></ul><ul><li>Peak Power 205 kW @ 5000 RPM </li></ul>
  4. 4. Experiments Undertaken & Result Viewing Points <ul><li>PHASE I </li></ul><ul><li>Tests at WOT by varying: </li></ul><ul><li>1) CR (6,10, 12.5,14) </li></ul><ul><li>2) ON (85,87,93,95,100,120) </li></ul><ul><li>3) Burn duration (20 o thru 60 o ) </li></ul><ul><li>4) 50% burn anchor point </li></ul><ul><li>(-20 o through 20 o ) </li></ul><ul><li>5) RPM sweep 1000 to 6000 </li></ul><ul><li>Results observed at: </li></ul><ul><li>Peak torque rpm (3500) </li></ul><ul><li>1500 rpm </li></ul><ul><li>PHASE II </li></ul><ul><li>Tests at part load </li></ul><ul><li>(1500 rpm/ 40 psi BMEP) </li></ul><ul><li>1) CR (6,10, 12.5,14) </li></ul><ul><li>2) ON (85,87,93,95,100,120) </li></ul><ul><li>3) Burn duration (20 o thru 60 o ) </li></ul><ul><li>4) 50% burn anchor point </li></ul><ul><li>(-20 o through 20 o ) </li></ul><ul><li>5) RPM sweep 1000 to 6000 </li></ul><ul><li>Results observed at: </li></ul><ul><li>1) 1500 rpm/40 psi BMEP </li></ul>
  5. 5. How do we deduce? <ul><li>From the data obtained: </li></ul><ul><li>for WOT </li></ul><ul><li>1) Brake torque vs. RPM </li></ul><ul><li>2) Knock Intensity vs. </li></ul><ul><li>RPM </li></ul><ul><li>3) Pressure at varying </li></ul><ul><li>50% Burn Pts at the specified RPMs </li></ul><ul><li>for Part Load Condition </li></ul><ul><li>1) BSFC vs. RPM </li></ul><ul><li>2) Brake torque vs. RPM </li></ul><ul><li>3) Knock Intensity vs. </li></ul><ul><li>RPM </li></ul><ul><li>4) Pressure at varying </li></ul><ul><li>50% Burn Pts at the specified RPMs </li></ul>
  6. 6. PHASE I : WOT Results and Graphs at WOT . 1 <ul><li>At C.R. 12.5, BDUR 40, THB50 20 </li></ul><ul><li>Knock Intensity vs. RPM </li></ul><ul><li>ON @ 1500 @ 3500 </li></ul><ul><li>85 0.70 0.55 </li></ul><ul><li>87 0.68 0.50 </li></ul><ul><li>93 0.56 0.35 </li></ul><ul><li>95 0.49 0.30 </li></ul><ul><li>100 0.40 0.15 </li></ul><ul><li>120 0.00 0.00 </li></ul><ul><li>Torque [ft.lbf] vs. RPM </li></ul><ul><li>ON @ 1500 @ 3500 </li></ul><ul><li>85 230 305 </li></ul><ul><li>87 231 306 </li></ul><ul><li>93 240 302 </li></ul><ul><li>95 240 300 </li></ul><ul><li>100 245 298 </li></ul><ul><li>120 248 295 </li></ul><ul><li>Result: </li></ul><ul><li>KNOCK limited torque @ 100 ON </li></ul>
  7. 7. Results and Graphs at WOT . 2 <ul><li>Pressure vs. CAD </li></ul><ul><li>@ 3500 rpm </li></ul><ul><li>ON Pressure *[10 6 pa] at 20 0 CA </li></ul><ul><li>85 7.2 </li></ul><ul><li>87 7.0 </li></ul><ul><li>93 5.4 </li></ul><ul><li>95 5.0 </li></ul><ul><li>100 4.8 </li></ul><ul><li>120 4.9 </li></ul><ul><li>@ 1500 rpm </li></ul><ul><li>ON Pressure* [10 6 pa] at 20 0 CA </li></ul><ul><li>85 7.8 </li></ul><ul><li>87 7.6 </li></ul><ul><li>93 6.1 </li></ul><ul><li>95 5.8 </li></ul><ul><li>100 4.6 </li></ul><ul><li>120 4.0 </li></ul>
  8. 8. Results and Graphs at WOT . 3 <ul><li>At ON 100, BDUR 40, THB50 20 </li></ul><ul><li>Knock intensity vs. RPM </li></ul><ul><li>CR @1500 @3500 </li></ul><ul><li>6 N/A N/A </li></ul><ul><li>10 0.23 0.00 </li></ul><ul><li>12.5 0.40 0.10 </li></ul><ul><li>14 0.60 0.37 </li></ul><ul><li>Torque vs. RPM </li></ul><ul><li>CR @1500 @3500 </li></ul><ul><li>6 N/A N/A </li></ul><ul><li>10 230 285 </li></ul><ul><li>12.5 235 300 </li></ul><ul><li>14 235 310 </li></ul>
  9. 9. Results and Graphs at WOT . 4 <ul><li>Pressure vs. CAD </li></ul><ul><li>@ 3500 rpm </li></ul><ul><li>CR Pressure *[10 6 pa] at 20 0 CA </li></ul><ul><li>6 N/A </li></ul><ul><li>10 4.05 </li></ul><ul><li>12.5 5.00 </li></ul><ul><li>14 6.00 </li></ul><ul><li>@ 1500 rpm </li></ul><ul><li>CR Pressure [10 6 pa] at 20 0 CA </li></ul><ul><li>6 N/A </li></ul><ul><li>10 3.40 </li></ul><ul><li>12.5 5.00 </li></ul><ul><li>14 7.00 </li></ul>
  10. 10. Results and Graphs at WOT . 5 <ul><li>50% burn anchor pt at CR 12.5 </li></ul><ul><li>Knock Intensity vs RPM </li></ul><ul><li>@ 3500 rpm @ 1500 rpm </li></ul><ul><li>ON -20 0 20 ON -20 0 20 </li></ul><ul><li>85 0.38 0.52 0.51 85 0.40 0.60 0.70 </li></ul><ul><li>100 0.28 0.42 0.40 100 0.30 0.52 0.10 </li></ul><ul><li>120 0.18 0.28 0.00 120 0.21 0.31 0.07 </li></ul><ul><li>Torque vs. RPM </li></ul><ul><li>@ 3500 rpm @ 1500 rpm </li></ul><ul><li>ON -20 0 20 ON -20 0 20 </li></ul><ul><li>85 205 275 310 85 115 180 240 </li></ul><ul><li>100 210 285 300 100 125 200 245 </li></ul><ul><li>120 225 298 298 120 135 230 247 </li></ul>
  11. 11. Results and Graphs at WOT . 6 <ul><li>CR 12.5 BDUR 40 ON 100 </li></ul><ul><li>Knock intensity vs. RPM vs. THB50 </li></ul><ul><li>SHOWS SAME RESULTS AS BEFORE </li></ul><ul><li>Torque vs. RPM vs. THB50 </li></ul><ul><li>SHOWS SAME RESULTS AS BEFORE </li></ul>
  12. 12. Results and Comments for WOT case <ul><li>With Increasing ON from 85 to 120 the knock intensity decreases by keeping the rest of the parameters constant </li></ul><ul><li>The Torque decreases under the same conditions reaches a KNOCK LIMITED value at ON 100 ( minimal knock and fairly good TORQUE) </li></ul><ul><li>Pressure also shows conforming results </li></ul><ul><li>With Increasing CR from 6 to 14 observations show increasing KNOCK INTENSITY (desired result) but varying TORQUE --- best KNOCK LIMITED torque at CR 12.5 </li></ul><ul><li>MAY give better results b/w 10.5 and 12.5 tested but included in the report </li></ul><ul><li>*** WAVE IS LIMITED TO PREDICTING KNOCK HIGHER THAN 7.5 CR *** </li></ul><ul><li>By varying the 50% BURN ANCHOR Pt from -20 o to 20 o it is observed that at every ON the KNOCK INTENSITY decrease but the TORQUE increases. At low end (1500 rpm) KNOCK LIMITED torque obtained at ON 120 and at high end(3500rpm) at ON 120 </li></ul><ul><li>***OVERALL THE WAVE KNOCK PREDICTION MODEL FUNCTIONS VERY WELL FOR *** </li></ul><ul><li>*** WOT CONDITIONS*** </li></ul>
  13. 13. PHASE II PART LOAD (1500 RPM/ 40psi BMEP) <ul><li>CHANGES MADE </li></ul><ul><li>1) 2 Throttle bodies added with plate angle 17 o to achieve 1500 rpm/40psi BMEP </li></ul><ul><li>2) The knock model will be tested for the various conditions </li></ul>
  14. 14. Results and Graphs at PART LOAD.1 <ul><li>At CR 10, BDUR 40, THB50 0 </li></ul><ul><li>Knock intensity vs. RPM </li></ul><ul><li>ON @1500 RPM </li></ul><ul><li>87 0.450 </li></ul><ul><li>93 0.375 </li></ul><ul><li>95 0.380 </li></ul><ul><li>0.300 </li></ul><ul><li>BSFC [lbm/hp/hr] vs. RPM </li></ul><ul><li>ON @1500 RPM </li></ul><ul><li>87 0.51 </li></ul><ul><li>93 0.49 </li></ul><ul><li>95 0.50 </li></ul><ul><li>0.45 </li></ul>
  15. 15. Results and Graphs at PART LOAD.2
  16. 16. Results and Graphs at PART LOAD.3 <ul><li>BDUR 20,THB50,40 CR 12.5 </li></ul><ul><li>Pressure*[10 6 ] Pa vs. CAD </li></ul><ul><li>ON @1500 </li></ul><ul><li>85 6.0 </li></ul><ul><li>87 5.7 </li></ul><ul><li>93 5.4 </li></ul><ul><li>95 4.2 </li></ul><ul><li>100 3.8 </li></ul><ul><li>3.6 </li></ul><ul><li>Knock Intensity vs. CAD </li></ul><ul><li>ON @1500 </li></ul><ul><li>85 0.60 </li></ul><ul><li>87 0.55 </li></ul><ul><li>93 0.45 </li></ul><ul><li>95 0.40 </li></ul><ul><li>100 0.28 </li></ul><ul><li>120 0.00 </li></ul>
  17. 17. Results and Comments for PART LOAD case <ul><li>With increasing ON at same THB50, BDUR and CR the KNOCK INTENSITY decreases and so does the BSFC </li></ul><ul><li>The pressure behaves in the same fashion for the same conditions and conforms to our KNOCK PREDICTION model </li></ul><ul><li>KNOCK MODEL shows 0.00 knock at 120 ON </li></ul><ul><li>With same CR and varying 50% burn anchor pt the BRAKE Torque </li></ul>
  18. 18. References <ul><li>WAVE 7.1 REFERNCE LIBRARY </li></ul><ul><li>Fundamentals of IC Engines By John Heywood </li></ul><ul><li>www.Google.com </li></ul><ul><li>www.Howstuffworks.com </li></ul><ul><li>ME 445 Class Notes </li></ul>
  19. 19. Acknowledgements <ul><li>Dr James Novak </li></ul><ul><li>Friends </li></ul><ul><li>Jayesh P.Kavathe </li></ul><ul><li>Rajat Basu </li></ul><ul><li>Pranav Sane </li></ul>
  20. 20. Q U E S T I O N S

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