1、_SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref
2、rom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2010 SAE International All rights reserved. No part of this publication ma
3、y be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 1+ 724-776-4970 (outside US
4、A) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/j2904_201001SURFACEVEHICLEINFORMATIONREPORTJ2904 JAN2010 Issued 2010-01 Power Cylinder Friction
5、: Mechanisms RATIONALENot applicable. TABLE OF CONTENTS 1. SCOPE 51.1 Purpose . 52. REFERENCES 53. DEFINITIONS . 64. BASICS OF FRICTION . 65. POWER CYLINDER COMPONENT - EFFECTS ON FRICTION 75.1 Piston 95.2 Ring Pack 95.2.1 Top Ring 95.2.2 Second Ring 95.2.3 Oil Ring . 95.3 Cylinder Bore 95.4 Oil Pro
6、perties 96. OTHER EFFECTS ON FRICTION 107. FRICTION CONTRIBUTION FIGURE 118. PISTON EFFECTS ON FRICTION . 128.1 Piston Mass (Minor Effect) 128.2 Piston Cooling (Minor Effect) 128.3 Piston Ring Grooves . 128.3.1 Angles (Medium Effect) . 128.3.2 Tilt (Minor Effect) . 138.3.3 Waviness (Minor Effect) 13
7、8.3.4 Surface Conditions (Medium Effect) . 148.3.5 Chamfers (Minor Effect) 148.3.6 Parallelism (Minor Effect) 158.3.7 Ring to Groove Clearances (Minor Effect) . 158.3.8 Ring Groove Material (Minor Effect) . 15SAE J2904 Issued JAN2010 Page 2 of 488.4 Piston Lands . 158.4.1 Diameters (Major Effect) .
8、158.4.2 Piston Land Heights (Minor Effect) . 158.4.3 Piston Land Axial Profiles (Major Effect) 168.4.4 Piston Land Circumferential Profiles (Major Effect) 178.4.5 Piston Land Coatings (Minor Effect) . 178.4.6 Piston Guidance by a Land (Major Effect) 178.4.7 Accumulator Grooves (Minor Effect) . 178.5
9、 Oil Drain 188.5.1 Oil Drain Holes (Minor Effect) . 188.5.2 Oil Drain Slots (Minor Effect) 188.5.3 Trans Slots (Major Effect) . 198.5.4 Drain along Sides of the Piston (Minor Effect) 198.5.5 Oil Drain to the Pin Bore (Minor Effect) 208.6 Piston Skirt 208.6.1 Piston Guidance or Piston Secondary Motio
10、n (Major Effect) . 208.6.2 Skirt Size (Major Effect) 238.6.3 Skirt Flexibility (Medium Effect) . 238.6.4 Skirt Surface Finish (Medium Effect) 238.6.5 Skirt Coatings (Major Effect) . 238.6.6 Skirt Chamfer (Minor Effect) . 238.7 External Effects on Piston Friction 248.7.1 Crankshaft Offset (Major Effe
11、ct) . 248.7.2 V-angle and Bank Effects (Minor Effect) . 248.8 Piston Pin Bore . 248.8.1 Unit Pressure on the Pin Bore (Medium Effect) 248.8.2 Pin Bore Design (Medium Effect) 258.8.3 Axial Piston Pin Bore Profile (Medium Effect) . 268.8.4 Circumferential Piston Pin Bore Profile (Medium Effect) 278.8.
12、5 Pin Bore Clearances (Medium Effect) 278.8.6 Pin Bore Material Effect (Medium Effect) 278.9 Piston Cooling (Medium Effect) 288.9.1 Connecting Rod Spray and Cooling Nozzles (Major Effect) . 288.10 Piston Temperatures (Major Effect) 288.10.1 Piston Thermal Distribution . 288.10.2 Oil Viscosities (Maj
13、or Effect) . 288.10.3 Carbon Build Up 289. PISTON RING EFFECTS ON FRICTION . 299.1 General Piston Rings 299.1.1 Circumferential Conformability (Minor Effect) . 299.1.2 Surface Conditions (Medium Effect) . 299.2 Compression Rings . 299.2.1 Ring Twist (Minor Effect) . 299.2.2 Angles (Medium Effect) 29
14、9.2.3 Closed Gap (Minor Effect) 299.2.4 Gap Ratios (Minor Effect) . 299.2.5 Ring Axial Width (Medium Effect) . 309.2.6 Ring Mass (Minor Effect) 309.2.7 Ring Circumferential Shape (Minor Effect) . 309.2.8 Tension of the Compression Ring (Medium Effect) 319.2.9 Face Profile (Medium Effect) 329.2.10 To
15、p Ring Face Profile (Medium Effect) . 329.2.11 Second Ring Face Profile (Medium Effect) . 339.2.12 End Gap Chamfer (Minor Effect) 349.2.13 OD Chamfers (Minor Effect) . 349.2.14 Waviness (Chatter) (Minor Effect) 359.2.15 Straightness (Minor Effect) . 369.2.16 Roughness (Medium Effect) . 36SAE J2904 I
16、ssued JAN2010 Page 3 of 489.3 Ring Materials (Medium Effect) . 369.3.1 Base Material (Minor Effect) . 369.3.2 Face Coating Material (Medium Effect) 369.4 Oil Ring . 369.4.1 General Oil Ring 379.4.2 Two Piece Oil Ring 379.4.3 Three Piece Oil Ring . 3810. CYLINDER BORE EFFECT ON FRICTION . 3910.1 Cyli
17、nder Bore Surface Finish (Major Effect) . 3910.1.1 Peak Honed Bore Surfaces (Major Effect) 3910.1.2 Plateau Honed Surface (Major Effect) 3910.1.3 Textured Surface (Medium Effect) 4010.1.4 Surface (Major Effect) . 4010.2 Cylinder Bore Honing Angle (Minor Effect) . 4010.3 Bore Distortion (Medium Effec
18、t) 4110.4 Cylinder Bore Material (Medium Effect) 4210.5 Cylinder Bore Coating (Medium Effect) . 4210.6 Chamfer at the Bottom of the Cylinder Bore (Minor Effect) 4210.7 Carbon Scraper Rings (Medium Effect) 4211. CONNECTING ROD (MEDIUM EFFECT) 4211.1 Connecting Rod Small End . 4211.1.1 Connecting Rod
19、Small End Unit Pressure (Medium Effect) . 4211.1.2 Connecting Rod Small End Design (Medium Effect) 4211.1.3 Small End Axial Profile (Medium Effect) . 4211.1.4 Circumferential Small End Pin Bore Profile (Medium Effect) 4211.1.5 Small End Pin Bore Clearances (Medium Effect) . 4211.1.6 Small End Pin Bo
20、re Material Effects (Minor Effect) 4311.2 Connecting Rod Big End Bearing Friction (Major Factor) 4311.2.1 Bearing Size 4311.2.2 Bearing Lubrication . 4311.2.3 Big End Oil Film Thickness and Peak Oil Film Pressure (Major Effect) . 4311.3 Connecting Rod to Crank Clearances (Minor Effect) . 4312. OIL E
21、FFECTS ON FRICTION (MAJOR EFFECT) . 4312.1 Viscosity (Major) 4312.2 Oil Temperature (Major) 4312.3 Oil Additives (Major) 4312.4 Oil Brand (Medium) . 4313. OIL JET OR OIL SQUIRTER EFFECTS ON FRICTION 4413.1 Oil Jet Targeting (Medium Effect) . 4413.2 Oil Jet Spray Angle (Medium Effect) . 4413.3 Types
22、of Oil Jet (Medium Effect) . 4414. PISTON PIN EFFECTS ON FRICTION (MEDIUM EFFECT) 4514.1 Pin Length (Medium Effect) 4514.2 Pin Diameter (Medium Effect) . 4514.3 Pin Stiffness (Medium Effect) 4514.4 Pin Surface Finish (Medium Effect) 4514.5 Pin Surface Hardness (Minor Effect) 4614.6 Pin Surface Coati
23、ng (Medium Effect) . 4615. SYSTEM EFFECTS ON FRICTION . 4615.1 Ring/Groove Side Clearance (Medium Effect) 4615.2 Ring/Groove Back Clearance (Medium Effect) . 4615.3 Connecting Rod to Crank Radius Ratio (L/r) (Major Effect) . 46SAE J2904 Issued JAN2010 Page 4 of 4816. ENGINE OPERATION 4616.1 Engine S
24、peed 4616.2 Engine Load 4616.3 Engine Maintenance . 4616.4 Fuel Injection Effects . 4616.4.1 Fuel Dilution 4616.4.2 Soot in the Oil 4716.4.3 Oil Burning 4716.5 Coolant Temperatures 4717. QUALITY ISSUES . 4717.1 Cylinder Bore Quality 4717.2 Piston Quality 4717.3 Piston Ring Quality 4717.4 Assembly Is
25、sues . 4717.4.1 Incorrect Rings in the Wrong Grooves 4717.4.2 Missing Rings 4817.4.3 Broken Rings . 4817.4.4 Lack of Proper Lubrication During Installation 4817.4.5 Excessive Core Sands from the Block or Head Casting 4817.4.6 Improper Torque Procedure when Assembling Cylinder Heads to Block 4817.4.7
26、 Improper O-rings in the Cylinder Liner 4818. OTHER EFFECTS 4818.1 Scuffing . 4818.2 Ring Sticking . 4819. NOTES 4819.1 Marginal Indicia . 48FIGURE 1 LOCATIONS OF POWER CYLINDER FRICTION . 7FIGURE 2 POWER CYLINDER . 8FIGURE 3 FRICTION CONTRIBUTION OF THE POWER CYLINDER COMPONENTS . 8FIGURE 4 POWER C
27、YLINDER FRICTION CONTRIBUTIONS 11FIGURE 5 ANGLES OF RINGS AND GROOVES . 12FIGURE 6 GROOVE UPTILT . 13FIGURE 7 GROOVE WAVINESS 14FIGURE 8 EFFECT OF THE LARGE OUTSIDE DIAMETER EDGE BREAK . 14FIGURE 9 LAND DIAMETERS . 15FIGURE 10 LAND PROFILES 16FIGURE 11 LAND AND SKIRT PROFILE EXAMPLE 16FIGURE 12 LAND
28、 ACCUMULATOR GROOVES 18FIGURE 13 OIL DRAIN TRANS SLOTS 19FIGURE 14 OIL DRAIN SLOTS . 19FIGURE 15 EXAMPLE OF THE EFFECT OF PIN OFFSET ON PISTON MOTION . 20FIGURE 16 PISTON PROFILES 21FIGURE 17 SKIRT AXIAL PROFILES 22FIGURE 18 SKIRT CIRCUMFERENTIAL CONTOURS 23FIGURE 19 SKIRT CHAMFERS 24FIGURE 20 ILLUS
29、TRATION OF THE UNIT PRESSURE CALCULATION . 25FIGURE 21 EXAMPLES OF PIN BORE DESIGNS . 25FIGURE 22 EXAMPLES OF PIN BORE CONTACT LOCATIONS 26FIGURE 23 EXAMPLES OF DIFFERENT PIN BORE AXIALPROFILES 26FIGURE 24 EXAMPLES OF DIFFERENT PIN BORE CIRCUMFERENTIAL PROFILES . 27FIGURE 25 AN EXAMPLE OF AN ALUMINU
30、M PISTON WITH PIN BORE BUSHINGS 27FIGURE 26 GALLERY COOLED PISTON . 28FIGURE 27 RING TWIST TERMINOLOGY . 29FIGURE 28 ILLUSTRATION OF RADIAL GAS FORCES ACTING ON THE RING 30FIGURE 29 EXAMPLE OF CALCULATED RING PRESSURE PATTERN . 31SAE J2904 Issued JAN2010 Page 5 of 48FIGURE 30 ILLUSTRATION OF RING TE
31、NSION MEASUREMENTS . 32FIGURE 31 EFFECT OF FACE PROFILE ON NET FORCE ACTING ON THE RING . 33FIGURE 32 SECOND RING FACE PROFILES . 33FIGURE 33 END GAP CHAMFER . 34FIGURE 34 SCHEMATICS OF BOTTOM SIDE OD CHAMFERS . 34FIGURE 35 RING COATING APPLICATION EXAMPLES 35FIGURE 36 WAVY RING EXAMPLE 35FIGURE 37
32、RING STRAIGHTNESS EXAMPLE 36FIGURE 38 TWO PIECE OIL RING . 38FIGURE 39 THREE PIECE OIL RING . 39FIGURE 40 PLATEAU HONED SURFACE . 40FIGURE 41 EXAMPLES OF THE EFFECTS OF BORE DISTORTION 41FIGURE 42 DIFFERENT ORDERS OF BORE DISTORTION . 41FIGURE 43 OIL SPRAY ANGLE 44FIGURE 44 OIL SQUIRTER EXAMPLES 451
33、. SCOPE This document covers the mechanisms from the power cylinder which contribute to the mechanical friction of an internal combustion engine. It will not discuss in detail the influence of other engine components or engine driven accessories on friction. 1.1 Purpose In internal combustion engine
34、s, the ability of an engine to generate its power potential to its fullest is hindered by the inherent internal friction of the sliding components and the friction of the engine driven accessories. In an era where power and fuel economy are key performance attributes, any operating condition which h
35、inders the ability of an engine to achieve these attributes is of primary interest to the engine designer. Any sliding surface in the engine contributes to the friction of an engine. According to Taylor, (Reference a), the friction of an internal combustion engine is partitioned between the piston a
36、nd ring assembly and the bearing, valve, and gear trains with the piston assembly accounting for 75% of the friction. Since the power cylinder friction is a major contributor to the over-all mechanical friction of the engine,any friction reduction goes directly to brake power with no increase in emi
37、ssions, will add thermal efficiency at no cost to the customer, and can potentially improve durability. Any attempt to minimize the friction of an engine logically starts with decreasing the friction of the piston assembly. This document focuses on the friction of the piston and ring assembly slidin
38、g in a lubricated bore, in an attempt to communicate the current best thinking on the subject of power cylinder friction. With this understanding, the engine designer or engine development engineer will be able to minimize the friction of the power cylinder assembly thereby contributing to the power
39、 output or fuel economy of an internal combustion engine.2. REFERENCES 2.1 Applicable Publications The following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest version of SAE publications shall apply. 2.1.1 SAE Publications Avail
40、able from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.SAE J1588 Internal Combustion EnginesPiston RingsVocabulary SAE J2612 Internal Combustion EnginesPiston Vocabulary SAE J2904 Issued JAN
41、2010 Page 6 of 482.2 Related Publications The following publications are provided for information purposes and are not a required part of this document. The Internal Combustion Engine in Theory and Practice, Volume 1, by Charles F. Taylor, M.I.T. Press, 1986 Handbook of Tribology, Materials, Coating
42、s, and Surface Treatments, by Bharat Bhushan and K. K. Gupta. McGraw-Hill, 1991“Review of Power Cylinder Friction for Diesel Engines,“ J. Eng. Gas Turbines Power 122, 506 (2000) 3. DEFINITIONS See SAE J2612, Piston Vocabulary for the piston nomenclature. See SAE J1588, Piston Ring Vocabulary for the
43、 piston ring nomenclature 4. BASICS OF FRICTION Friction is the resistance to relative motion of contacting bodies. Friction force and friction power loss are two basic methods to characterize friction. Friction power losses are of most concern regarding fuel consumption. Friction forces can be very
44、 high but have a small effect on power losses. Friction forces may be better correlated to wear and durability. Friction experienced during a sliding condition is known as sliding friction, and the friction experienced during a rolling condition is known as rolling friction. The friction in the powe
45、r cylinder is exclusively sliding friction. (Reference b) The friction between lubricated sliding surfaces can be classified into the following lubrication regimes; hydrodynamic, mixed lubrication, and boundary lubrication. Hydrodynamic lubrication between sliding surfaces occurs when the lubricatin
46、g film thickness is sufficient in thickness to avoid asperity contact. Friction in this regime is caused by shear resistance of the oil film. Boundary lubrication occurs when the film thickness is insufficient to separate the adjacent sliding surfaces and friction is dominated by asperity contact. M
47、ixed lubrication occurs when the film thicknesses transition between the hydrodynamic and boundary regimes. Friction tends to be highest in the boundary regime and is characterized by high wear rates. Within the Mixed and boundary regime, friction is due to the various combined effects of adhesion b
48、etween the contacting surfaces, ploughing by wear particles and hard surface asperity, and asperity deformation. The relative contribution of these components depends on the specific material used, the surface topography, the conditions of sliding interface, and the environment.The components that a
49、ffect the power cylinder friction are the piston, piston rings, cylinder bore, wrist pin, and the lubricant. The piston assembly slides against the lubricated cylinder bore and wrist pin, and it is this sliding contact that generates the mechanical friction of the power cylinder. By the inherent design of the internal combustion engine, the piston undergoes a wide range of velocities; with zero velocity at top dead center (TDC) and bottom de
