Abstract
This work explores the impact of the interaction of lubricant and fuel properties on the propensity for stochastic pre-ignition (SPI). Findings are based on statistically significant changes in SPI tendency and magnitude, as determined by measurements of cylinder pressure. Specifically, lubricant detergents, lubricant volatility, fuel volatility, fuel chemical composition, fuel-wall impingement, and engine load were varied to study the physical and chemical effects of fuel-lubricant interactions on SPI tendency. The work illustrates that at low loads, with fuels susceptible to SPI events, lubricant detergent package effects on SPI were non-significant. However, with changes to fuel distillation, fuel-wall impingement, and most importantly engine load, lubricant detergent effects could be observed even at reduced loads This suggests that there is a thermal effect associated with the higher load operation. It was hypothesized that the thermal effect was associated with lube oil nitrogenation. To test this theory, nitromethane (CH3NO2) was blended at 6.5% by volume CH3NO2 resulted in significant sensitivity to lubricant additive package effect on SPI, even at reduced loads where no lubricant sensitivity was observed without the addition of CH3NO2. The combined results highlight the interplay of fuel-lubricant interaction on SPI events, but more importantly suggest that there is the potential of a chemical interaction unique to high-load engine operation that results in reactive chemical processes, such as nitration, where lubricant chemistry becomes an active pathway for SPI activity.
| Original language | English |
|---|---|
| Journal | SAE Technical Papers |
| Volume | 2019-September |
| Issue number | September |
| DOIs | |
| State | Published - Sep 9 2019 |
| Event | SAE 14th International Conference on Engines and Vehicles, ICE 2019 - Capri, Italy Duration: Sep 15 2019 → Sep 19 2019 |
Funding
This work was funded by the US Department of Energy's Vehicle Technologies Office under the Lubricants Technologies Program. Program managers Kevin Stork, Michael Weismiller. This research was conducted as part of the Co-Optimization of Fuels & Engines (Co-Optima) project sponsored by the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies and Vehicle Technologies Offices. Co-Optima is a collaborative project of multiple National Laboratories initiated to simultaneously accelerate the introduction of affordable, scalable, and sustainable biofuels and high-efficiency, low-emission vehicle engines. A special thanks to program managers Kevin Stork, Gurpreet Singh, and Mike Weismiller. ASTM ASTM International aTDC f after firing top dead center C Celsius CA crank angle CAFE corporate average fuel economy CA04 crank angle of 4% cumulative heat release CA50 crank angle of 50% cumulative heat release CH 3 NO 2 nitromethane CoV coefficient of variation F Fahrenheit FBP final boiling point IBP initial boiling point ID Ignition delay IMEPg gross indicated mean effective pressure IQT Ignition Quality Tester K degrees kelvin kg Kilogram kJ kilo joule KLSA Knock limited spark advance kPa kilo pascal LHV lower heating value LLNL Lawrence Livermore National Laboratory LSPI low speed pre-ignition LTHR low-temperature heat release mm millimeter MON motor octane number mol. % molar percentage ms millisecond NTC negative temperature coefficient OEM original equipment manufacturer P max maximum cylinder pressure ppm parts per million PSHR pre-spark heat release r/min revolutions per minute RON research octane number SAE Society of Automotive Engineers SI spark ignited SPI stochastic pre-ignition T10 temperature of 10% distillation T50 temperature of 50% distillation T90 temperature of 90% distillation TDC top dead center vol. % volume percentage wt. % weight percentage ° degrees This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC0500OR22725, and by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for the United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).
| Funders | Funder number |
|---|---|
| US Department of Energy's | |
| UT-Battelle | DE-AC0500OR22725 |
| Vehicle Technologies Offices | |
| U.S. Department of Energy | |
| Office of Energy Efficiency and Renewable Energy | |
| Lawrence Livermore National Laboratory | DE-AC52-07NA27344 |
| Vehicle Technologies Office |
