Development and Evaluation of a Friction Model for Spark-Ignition Engines

Patton, Kenneth J.; Nitschke, Ronald C.; Heywood, John B.

doi:10.4271/890836

Cited by 168 publications

(81 citation statements)

References 17 publications

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“…These constants, which vary from seal to seal, are determined empirically. Some researchers [6] consider another loss mechanism due to the power loss from pumping oil through the crankshaft oil feeds. However, strictly, this is not "rubbing" friction as discussed earlier in this article, but could actually be considered part of the accessories power losses.…”

Section: The Crankshaft Main-bearing Subsystemmentioning

confidence: 99%

Overview of automotive engine friction and reduction trends–Effects of surface, material, and lubricant-additive technologies

Wong

Tung²

2016

Friction

275

140

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Abstract:The increasing global environmental awareness, evidenced by recent worldwide calls for control of climate change and greenhouse emissions, has placed significant new technical mandates for automotives to improve engine efficiency, which is directly related to the production of carbon dioxide, a major greenhouse gas. Reduction of parasitic losses of the vehicle, powertrain and the engine systems is a key component of energy conservation. For engine efficiency improvement, various approaches include improvements in advanced combustion systems, component system design and handling-such as down-sizing, boosting, and electrification-as well as waste heat recovery systems etc. Among these approaches, engine friction reduction is a key and relatively cost-effective approach, which has been receiving significant attention from tribologists and lubricant-lubrication engineers alike. In this paper, the fundamentals of friction specific to the environments of engine components tribology are reviewed, together with discussions on the impact of developing vehicle powertrain technologies, surface and material technologies, as well as lubricant and additive technologies on promises of continuing friction and wear reduction trends. The international accords on climate change require further gains in fuel efficiency and energy sustainability from all industry sectors including those in the automotive and the broader internal combustion engine industries, and the latter encompass off-highway, power generation, marine, and rail industries as well. This paper focsuses on friction reduction in mainly automotive engines, however.The paper starts with a clarification of the common descriptors of mechanical losses and friction in the engine, followed by the topic of lubrication fundamentals such as lubrication regimes. Then the lubrication of the contacting surfaces in each of the major engine subsystems is discussed in turn. These subsystems include the piston assembly: ring-pack/liner, piston-skirt/liner, and piston-pin/connecting-rod contacts; connecting rod and crankshaft bearings; and the valvetrain subsystem. The relative contributions to total friction from the various subsystems are discussed, with the piston-assembly contributing to about half of the total friction. The remainder of the friction comes from the crankshaft, connecting rod, camshaft bearings, and the valvetrain oscillating parts. The bearings are in predominantly hydrodynamic lubrication, in contrast to the valvetrain oscillating components, which are characterized to be mostly in the mixed/boundary lubrication regimes.Despite the title of the paper, a section on emerging powertrain technologies-including that of combustion in gasoline and diesel engines-is also given in the context of the trend towards clean and efficient propulsion systems. The impact of these developing technologies on the reduction of friction and parasitic losses via component, material, and lubricant deisgn will be discussed. These technologies include gasoline direct injection (GD...

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Section: The Crankshaft Main-bearing Subsystemmentioning

confidence: 99%

Overview of automotive engine friction and reduction trends–Effects of surface, material, and lubricant-additive technologies

Wong

Tung²

2016

Friction

275

140

View full text Add to dashboard Cite

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“…Considering the design particularities of the engine; the experimental results of Ionut and Moldovanu (1982), , and Patton et al (1989); and the theory of lubrication (Tudor et al 1988) the values and relationships of the friction model coefficients are presented in Table 2 (N was estimated at 700 min -1 ). The relationships used to calculate the SLM friction model coefficients presented in Table 2 cannot be used for other engine models; however, they can be used for further research and simulations regarding the influence of different oil viscosities on friction losses for the diesel engines considered.…”

Section: Computer Simulationmentioning

confidence: 99%

Possibilities for reducing tractor engine friction losses at cold start using an ultrasonic irradiation technique

Mariașiu¹

2013

Turk J Agric For

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Redox copolymerization of N-vinyl-2-pyrrolidone (NVP) with methyl methacrylate (MMA) was carried out using titanium(III)-dimethylglyoxime [Ti(III)-DMG] redox initiator in aqueous sulfuric acid-alcohol media. The resulting copolymer was characterized by FTIR, 1 H-NMR, and 13 C-NMR spectroscopic methods and elemental analysis. Thermal properties of the copolymer were determined by differential scanning calorimetric technique and thermogravimetric analysis. The reactivity ratios of the monomers were computed by Fineman-Ross, Kelen-Tudos, and extended Kelen-Tudos methods at lower conversion.The reactivity ratios obtained r 1 (MMA) 1.69 and r 2 (NVP) 0.03 showed richer content of MMA than NVP in the copolymer having extreme ideal behavior. The distribution of monomer sequence along the copolymer chain was calculated using a statistical method based on reactivity ratios. Ti(III)-DMG redox initiator showed increased addition of NVP to MMA during copolymerization.

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“…While updated friction correlations are available that reflect decreased friction losses in modern engines and incorporate more factors [60][61][62][63], we used the correlation of Eq. (3) to match the age of the SI engine used for the driving cycle simulations [57].…”

Section: Driving Cycle Simulationmentioning

confidence: 99%

Investigation of the LTC fuel performance index for oxygenated reference fuel blends

Niemeyer

Daly

Cannella

et al. 2015

Fuel

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A new metric for ranking the suitability of fuels in LTC engines was recently introduced, based on the fraction of potential fuel savings achieved in the FTP-75 light-duty vehicle driving cycle. In the current study, this LTC fuel performance index was calculated computationally and analyzed for a number of fuel blends comprised of n-heptane, isooctane, toluene, and ethanol in various combinations and ratios corresponding to octane numbers from 0 to 100. In order to calculate the LTC index for each fuel, computational driving cycle simulations were first performed using a typical light-duty passenger vehicle, providing pairs of engine speed and load points. Separately, for each fuel blend considered, single-zone naturally aspirated HCCI engine simulations with a compression ratio of 9.5 were performed in order to determine the operating envelopes. These results were combined to determine the varying improvement in fuel economy offered by fuels, forming the basis for the LTC fuel index. The resulting fuel performance indices ranged from 36.4 for neat n-heptane (PRF0) to 9.20 for a three-component blend of n-heptane, isooctane, and ethanol (ERF1). For the chosen engine and chosen conditions, in general lower-octane fuels performed better, resulting in higher LTC fuel index values; however, the fuel performance index correlated poorly with octane rating for less-reactive, higher-octane fuels.

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Development and Evaluation of a Friction Model for Spark-Ignition Engines

Cited by 168 publications

References 17 publications

Overview of automotive engine friction and reduction trends–Effects of surface, material, and lubricant-additive technologies

Overview of automotive engine friction and reduction trends–Effects of surface, material, and lubricant-additive technologies

Possibilities for reducing tractor engine friction losses at cold start using an ultrasonic irradiation technique

Investigation of the LTC fuel performance index for oxygenated reference fuel blends

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