Development of Glycerin (1,2,3-propanetriol)-based Antifreeze With Advanced Nitrite-Free Carboxylate Inhibitors for Light-, Medium-, and Heavy-Duty Engine Cooling Systems

摘要

In 1997 a need was identified for environmentally preferred products to be used in government, military, and commercial transportation companies. By 2007 technologies had been developed that enabled the cost-effective expansion of glycerin-based products to industrial heating and cooling (HVAC) applications, allowing the attractive environmental properties of aqueous glycerin solutions to be realized in HVAC applications. While researching and developing the HVAC market, engineers were surprised to find a dearth of standards, including automotive standards, against which to evaluate glycerin-based antifreeze. In the absence of specifications for glycerin-containing fluids, ASTM D6210 was selected as the benchmark because of its diverse selection of material compatibility and performance requirements. Prototype aqueous glycerin coolant chemistry was tested and found to conform to the performance and material compatibility requirements of ASTM D6210. A similar specification that describes the physical properties of glycerin was developed by ASTM Committee D15 on Engine Coolants and Related Fluids and published in 2011 as ASTM D7715. Laboratory testing followed, with successful vehicle fleet testing conducted over a two-year period. This paper documents the development of an extended-life carboxylate-inhibited glycerin-based engine coolant/antifreeze formulation and the glycerin specifications now published as ASTM D7714 and ASTM D7715. It further discusses the advantages of glycerin as opposed to the more conventional molecules ethylene glycol (1,2-ethanediol) and propylene glycol (1,2-propanediol).