High Ethanol Fuel Endurance Advanced Engineering Project A

High Ethanol Fuel Endurance Advanced Engineering Project A study of the effects of running 15% ethanol concentration in current production 4 -stroke engines and “legacy” 2 -stroke engines. Prepared By: Dave Hilbert

Overview This project is a cooperative effort to assess the feasibility of increasing the allowable ethanol concentration in gasoline above the current legal limit of 10% for use in marine engines. § Objectives of this project: – Run 300 hours of wide-open throttle endurance on 3 engine families and measure emissions at 0, 150, and 300 hours. § 9. 9 HP 4 -stroke carbureted, 200 HP 2. 5 L 2 -stroke EFI (represents “legacy” product) and 300 HP L 6 SC Verado engines were chosen. § Two engines from each family – Test engine operated on E 15 – Control engine run on pure gasoline 2 Brunswick, Confidential 6/7/2021

Test Engine Specifications 3 Brunswick, Confidential 6/7/2021

Results Summary § Verado – Initial E 15 engine generated HC+NOx emissions in excess of FEL when operated on E 15 fuel. – E 15 engine failed exhaust valves. Metlab analysis showed excessive metal temperatures caused a reduction in fatigue strength. § F 9. 9 HP – The E 15 engine on E 15 fuel showed high HC variability at the post-endurance emissions testing. It is believed that this engine was misfiring at idle due to the lean operation. – The E 15 engine showed evidence of hotter metal temperatures due to carbon deposits, etc. – The E 15 engine showed signs of gasket deterioration on the fuel pump. § 200 HP EFI 2. 5 L 2 Stroke – E 15 engine showed no difference in emission deterioration. – E 15 engine failed the rod bearing. Root cause is indeterminate due to the degree of damage. § How does ethanol affect oil dispersion in two stroke engines? – Other than the bearing failure, the end of test teardown and inspection did not show any significant difference between the 2 engines 4 Brunswick, Confidential 6/7/2021

Results Summary-Continued § 4. 3 L V 6 ECT Mercruiser – Two emissions tests were performed on a 4. 3 L catalyzed sterndrive engine to compare the E 0 fuel and the E 15 fuel. No durability testing was completed on the 4. 3 L engine with E 15 fuel. – This testing was not part of the contract, but was performed due to the fact that the E 15 test fuel and a catalyzed engine were readily available on the dyno. Also, it compliments the testing on a 4. 3 L carbureted engine done by Volvo Penta. – EGT increased ~20 C and catalyst temperatures increased ~32 C at Mode 1 (WOT). § Valvetrain durability and catalyst system deterioration concerns. – Fuel consumption increased by ~5% (mass-based fuel flow) in closed loop operation. – Aside from HC and CO reductions at Mode 1 (open loop), the E 15 fuel afforded no real benefit to reduced emissions overall. § NOx increased at Mode 1, but not as much as HC decreased for a slight overall reduction. § HC, NOx and CO in closed loop operation are essentially unchanged between the 2 fuels. § Overall – The CO emissions were lower on all engines with E 15 fuel due to leaner running (as would be expected). – Fuel analysis showed the E 15 fuel that was used in testing was in line with expectations. 5 Brunswick, Confidential 6/7/2021

Conclusions and Recommendations Summary § Despite the limited scope of project several significant issues were discovered. – Durability Failures – Emissions Issues (elevated NOx, HC variability) – Run Quality due to Lean Operation § More testing is necessary to understand effects on: – Driveability- Ex. cold and hot start, transient accel/decel, “boiloff”, etc. – Oil dispersion in 2 stroke engines – Storage (phase separation, corrosion, etc. ) § Test program was a cursory look at the effects of E 15. – Sample size was insufficient to have statistical significance. – WOT operation only-masks effects of true customer duty cycle 6 Brunswick, Confidential 6/7/2021

Fuel Comparison 7 Brunswick, Confidential 6/7/2021

Fuel Comparison 8 Brunswick, Confidential 6/7/2021

F 9. 9 HP 4 -Stroke Emissions § Variability on E 15 Engine is a concern. – “E 15 fuel-zero hour” and “EEE-E 0 fuel 150 hour” checks are likely due to run-torun variability. – “E 15 fuel-300 hour” variability is due primarily from Mode 5 (idle) HC emissions. § Trends on EEE-E 0 fuel are consistent between the 2 engines. 9 Brunswick, Confidential 6/7/2021

F 9. 9 HP 4 -Stroke Emissions § Both engines had a tendency to run leaner at Modes 4 and 5 with increasing endurance time. § The combination of the inherent leaner operation and the E 15 fuel was enough to cause misfires/poor combustion at idle. § The misfires caused the HC emissions to increase and become highly variable. RICH LEAN 10 Brunswick, Confidential 6/7/2021

F 9. 9 HP 4 -Stroke Emissions § The fact that the E 15 fuel emissions tests show that HC emissions increase with leaner mixtures supports the misfire theory. § The graph below shows HC vs. equivalence ratio at idle for every emissions test performed on engine 0 R 352904, which is the “E 15 engine”. – All E 15 fuel emissions tests are shown in red – All EEE-E 0 fuel emissions test are shown in blue 11 Brunswick, Confidential 6/7/2021

F 9. 9 HP 4 -Stroke Teardown and Inspection § More carbon deposits on intake valves of E 15 engine. 12 Brunswick, Confidential 6/7/2021

F 9. 9 HP 4 -Stroke Teardown and Inspection § More carbon deposits on intake port of E 15 engine. E 0 E 15 13 Brunswick, Confidential 6/7/2021

F 9. 9 HP 4 -Stroke Teardown and Inspection § More carbon deposits on piston undercrown and rods of E 15 engine. 14 Brunswick, Confidential 6/7/2021

F 9. 9 HP 4 -Stroke Teardown and Inspection § The gasket showed signs of deterioration on the E 15 engine compared with the E 0 engine. § The gasket on the E 15 engine had a pronounced ridge formed in the area that “hinges” when the check valve is in operation § The E 15 gasket material in the area that seals the check valve also had signs of wear that were more advanced than the E 0 gasket. E 15 E 0 15 Brunswick, Confidential 6/7/2021

F 9. 9 HP 4 -Stroke Teardown and Inspection § Material transfer from gasket to diaphragm in mechanical fuel pump. E 15 E 0 16 Brunswick, Confidential 6/7/2021

Verado Testing Summary / Review § Verado E 15 Engine: – Initial emissions tests on E 15 fuel generated HC+NOx values in excess of the FEL set for this engine. § Three-run average on E 15 fuel: HC+NOx = 25. 6 g/kw-hr § FEL set to 22. 0 g/kw-hr – E 15 engine failed the exhaust valves. § High cycle fatigue due to elevated temperatures 17 Brunswick, Confidential 6/7/2021

Verado E 15 Valve Failure Investigation Cylinder 3 Bottom Valve Cylinder 3 Top Valve Cylinder 6 Top Valve 18 Brunswick, Confidential 6/7/2021

Verado E 15 Valve Failure Investigation Cylinder 3 Bottom Valve 19 Brunswick, Confidential 6/7/2021

Verado E 15 Valve Failure Investigation § The failed valves were checked for hardness and the values were low. § Valves from other E 0 engines w/o failed valves were measured and the hardness values were within expected values. § Brand new valves were also measured for comparison. 20 Brunswick, Confidential 6/7/2021

Verado E 15 Valve Failure Investigation § The new valves that were hardness checked were then oven-aged for 24 hours and the hardness was checked again. § A simple linear interpolation would indicate the E 0 valve temperature was around 780°C and the E 15 valve temperature was approx. 890°C or higher. § The measured change in exhaust gas temperature was only 25 -30°C. 21 Brunswick, Confidential 6/7/2021

200 HP EFI 2. 5 L Two-Stroke Testing § There was more variability in HC+NOx on the E 0 engine than any of the changes on the E 15 engine. § The trend of CO emissions change vs. endurance time was similar between the 2 engines. § The rod bearing failure on the E 15 engine prevented completing the testing. § Due to the extensive damage, the cause of the bearing failure could not be definitively determined. – Assembly error causing a step at the rod / cap interface? § If so, why did it run 250+ hours of WOT? – What effects would the ethanol have on oil dispersion? 22 Brunswick, Confidential 6/7/2021

200 HP EFI 2. 5 L Two-Stroke Emissions 23 Brunswick, Confidential 6/7/2021

200 HP EFI E 15 Engine-Bearing Failure § Root cause of bearing failure is unknown. § 283 total engine hours, 256 WOT endurance hours § No rollers were recovered. Remaining Pieces from Cyl 3 Rod Bearing Cage Undamaged Bearing Undamaged Rod 24 Rod from Cyl 3 Brunswick, Confidential 6/7/2021

Additional Testing-4. 3 L V 6 ECT Fuel Comparison § Increase in EGT of 20°C, increase in catalyst temperature of 32°C at Mode 1. § No appreciable difference in emissions during closed loop operation. § Changes in HC and CO at Mode 1 are expected due to lean operation. § “The increase in catalyst temperature at WOT will cause more rapid deterioration of the catalyst system leading to higher exhaust emissions over the lifetime of the engine. ” § Increase in fuel consumption (mass basis) of ~5% in closed-loop operation. 25 Brunswick, Confidential 6/7/2021