One of the requirements of engine lubricating oil is that it must have a low enough viscosity at low temperatures to assist in cold starting and a high enough viscosity at high temperatures to maintain its load-bearin...One of the requirements of engine lubricating oil is that it must have a low enough viscosity at low temperatures to assist in cold starting and a high enough viscosity at high temperatures to maintain its load-bearing characteristics. Viscosity Index (VI) is one approach used widely in the lubricating field to assess the variation of viscosity with temperature. The VI of both mineral and synthetic base oils can be improved by the addition of polymeric viscosity modifiers (VMs). VI improvement by VMs is widely attributed to the polymer coil size expanding with increasing temperature. However, there is very little physical data supporting this generally accepted mechanism. To address this issue, intrinsic viscosity measurements and Small-Angle Neutron Scattering (SANS) have been used to study the variation of polymer coil size with changing temperature and concentration in a selection of solvents. The results will show that coil size expansion with temperature is not necessary to achieve significant elevation of viscosity index.展开更多
Internal combustion engines′ fuel economy is an important role for engine designers,engine manufacturers over the past 30 years,especially passenger car motor oils.In heavy duty diesel engine,over the past 20 years,f...Internal combustion engines′ fuel economy is an important role for engine designers,engine manufacturers over the past 30 years,especially passenger car motor oils.In heavy duty diesel engine,over the past 20 years,fuel economy has in some cases been sacrificed for exhaust gas emission optimizations.Now,Heavy Duty Automotive and the related industries have strong interest in fuel economy and the lubricants.It is driven by competitive market forces as well as government mandates and new emission regulations.Japan was the first country in the world to establish and implement heavy duty trucks and buses fuel economy standards.Other countries also have followed either by establishing direct fuel economy standards or greenhouse gas(GHG) emissions standards which are directly tied to fuel economy.This paper is discussing that heavy duty diesel engine lubricants can contribute on fuel economy.The contribution of various aspects of engine oil formulations on fuel economy will be discussed such as lubricant viscosity grade,lubricant additives and friction modifiers.In this paper,the evaluation discussions are based on fuel economy measurements in some bench tests,standardized laboratory engine tests and field tests.展开更多
High viscosity asphalt(HVA)has been a great success as a drainage pavement material.However,the larger porosity of drainage asphalt mixtures weakens the cohesion and adhesion and leads to premature rutting,water damag...High viscosity asphalt(HVA)has been a great success as a drainage pavement material.However,the larger porosity of drainage asphalt mixtures weakens the cohesion and adhesion and leads to premature rutting,water damage,spalling and cracking.The purpose of this study was to investigate the rheological properties of HVA prepared using different high viscosity modifiers through conventional tests,Brookfield viscosity tests,dynamic shear rheometer tests and bending beam rheometer tests.The conventional performance results demonstrated SBS+rubber asphalt(SRA1/2)exhibited excellent elastic recovery and low-temperature flexibility.The 60℃ dynamic viscosity results indicated TPS+rubber asphalt(TRA)had the excellent adhesion.The rotational viscosity results and rheological results indicated that SRA-2 not only exhibited excellent temperature stability and workability,as well as excellent resistance to deformation and rutting resistance,but also exhibited excellent low-temperature cracking resistance and relaxation performance.Based on rheological results,the PG classification of HVA was 16%rubber+asphalt for PG76-22,20%rubber+asphalt for PG88-22,TRA and SRA-1/2 for PG88-28.From comprehensive evaluation of the viscosity,temperature stability and sensitivity,as well as high/low temperature performance of HVA,SRA-2 was found to be more suited to the requirements of drainage asphalt pavement materials.展开更多
Fuel economy regulations have been issued in many countries to save energy,and it is one of the most essential performance requirements for Passenger Car Motor Oil(PCMO) this decade.The performance is also important t...Fuel economy regulations have been issued in many countries to save energy,and it is one of the most essential performance requirements for Passenger Car Motor Oil(PCMO) this decade.The performance is also important to reduce green house gas(GHG) emissions.Automotive,Oil and Additive industries have been developing fuel economy tests in fired engine for PCMO.The ASTM 5 Car test was started in 1982 and ASTM Sequence Ⅵ series test was also developed by the industries as one of fuel economy tests after the 5 Car test.However,the fired engine(combustion) test condition is more complicated and the combustion mode in engine introduce high variability into a fuel economy measurement.Screening by bench testing is complicated by the difficulty to reproduce friction conditions of all of engine parts.Based on the background,a motored engine friction torque test(MEFT) was developed as one of the solutions for fuel economy screening test.Using a newly developed MEFT,key additive chemistries were evaluated and compared in the test,and it distinguished the differences in additive chemistries,in addition to those in viscosity and friction modifiers.The Sequence Ⅵ-D FEI 1(Seq.Ⅵ-D FEI 1) and chassis dynamometer vehicle tests were also conducted in this study,and the test data has shown an excellent correlation among MEFT,Seq.Ⅵ-D FEI 1 and chassis dynamometer vehicle tests.展开更多
文摘One of the requirements of engine lubricating oil is that it must have a low enough viscosity at low temperatures to assist in cold starting and a high enough viscosity at high temperatures to maintain its load-bearing characteristics. Viscosity Index (VI) is one approach used widely in the lubricating field to assess the variation of viscosity with temperature. The VI of both mineral and synthetic base oils can be improved by the addition of polymeric viscosity modifiers (VMs). VI improvement by VMs is widely attributed to the polymer coil size expanding with increasing temperature. However, there is very little physical data supporting this generally accepted mechanism. To address this issue, intrinsic viscosity measurements and Small-Angle Neutron Scattering (SANS) have been used to study the variation of polymer coil size with changing temperature and concentration in a selection of solvents. The results will show that coil size expansion with temperature is not necessary to achieve significant elevation of viscosity index.
文摘Internal combustion engines′ fuel economy is an important role for engine designers,engine manufacturers over the past 30 years,especially passenger car motor oils.In heavy duty diesel engine,over the past 20 years,fuel economy has in some cases been sacrificed for exhaust gas emission optimizations.Now,Heavy Duty Automotive and the related industries have strong interest in fuel economy and the lubricants.It is driven by competitive market forces as well as government mandates and new emission regulations.Japan was the first country in the world to establish and implement heavy duty trucks and buses fuel economy standards.Other countries also have followed either by establishing direct fuel economy standards or greenhouse gas(GHG) emissions standards which are directly tied to fuel economy.This paper is discussing that heavy duty diesel engine lubricants can contribute on fuel economy.The contribution of various aspects of engine oil formulations on fuel economy will be discussed such as lubricant viscosity grade,lubricant additives and friction modifiers.In this paper,the evaluation discussions are based on fuel economy measurements in some bench tests,standardized laboratory engine tests and field tests.
基金The work described in this paper is supported by the National Natural Science Foundation of China under Grant No.51778136Technology Research and Development Project of China Railway under No.J2019G003.
文摘High viscosity asphalt(HVA)has been a great success as a drainage pavement material.However,the larger porosity of drainage asphalt mixtures weakens the cohesion and adhesion and leads to premature rutting,water damage,spalling and cracking.The purpose of this study was to investigate the rheological properties of HVA prepared using different high viscosity modifiers through conventional tests,Brookfield viscosity tests,dynamic shear rheometer tests and bending beam rheometer tests.The conventional performance results demonstrated SBS+rubber asphalt(SRA1/2)exhibited excellent elastic recovery and low-temperature flexibility.The 60℃ dynamic viscosity results indicated TPS+rubber asphalt(TRA)had the excellent adhesion.The rotational viscosity results and rheological results indicated that SRA-2 not only exhibited excellent temperature stability and workability,as well as excellent resistance to deformation and rutting resistance,but also exhibited excellent low-temperature cracking resistance and relaxation performance.Based on rheological results,the PG classification of HVA was 16%rubber+asphalt for PG76-22,20%rubber+asphalt for PG88-22,TRA and SRA-1/2 for PG88-28.From comprehensive evaluation of the viscosity,temperature stability and sensitivity,as well as high/low temperature performance of HVA,SRA-2 was found to be more suited to the requirements of drainage asphalt pavement materials.
文摘Fuel economy regulations have been issued in many countries to save energy,and it is one of the most essential performance requirements for Passenger Car Motor Oil(PCMO) this decade.The performance is also important to reduce green house gas(GHG) emissions.Automotive,Oil and Additive industries have been developing fuel economy tests in fired engine for PCMO.The ASTM 5 Car test was started in 1982 and ASTM Sequence Ⅵ series test was also developed by the industries as one of fuel economy tests after the 5 Car test.However,the fired engine(combustion) test condition is more complicated and the combustion mode in engine introduce high variability into a fuel economy measurement.Screening by bench testing is complicated by the difficulty to reproduce friction conditions of all of engine parts.Based on the background,a motored engine friction torque test(MEFT) was developed as one of the solutions for fuel economy screening test.Using a newly developed MEFT,key additive chemistries were evaluated and compared in the test,and it distinguished the differences in additive chemistries,in addition to those in viscosity and friction modifiers.The Sequence Ⅵ-D FEI 1(Seq.Ⅵ-D FEI 1) and chassis dynamometer vehicle tests were also conducted in this study,and the test data has shown an excellent correlation among MEFT,Seq.Ⅵ-D FEI 1 and chassis dynamometer vehicle tests.
