Publishing Venue
The IP.com Prior Art Database
Abstract
The present disclosure relates to a method of preventing residues of non-combusted ED95 from depositing on surfaces of a turbocharger of a vehicle by coating the relevant surfaces with a coating having a reduced affinity for ED95 residues. The coating is a thermal barrier coating (TBC) having both thermal barrier properties and modified surface properties. Thus, two advantages are achieved with a single coating: thermal losses are reduced and deposition of ED95 residues is prevented. Turbocharger components coated with a TBC, such as the turbine shaft, bearing housing, turbine wheel and blades, are also disclosed.
TURBOCHARGER
COMPONENTS HAVING A THERMAL BARRIER COATING
ABSTRACT
The present disclosure
relates to a method of preventing residues of non-combusted ED95 from
depositing on surfaces of a turbocharger of a vehicle by coating the relevant
surfaces with a coating having a reduced affinity for ED95 residues. The
coating is a thermal barrier coating (TBC) having both thermal barrier
properties and modified surface properties. Thus, two advantages are achieved
with a single coating: thermal losses are reduced and deposition of ED95
residues is prevented. Turbocharger components coated with a TBC, such as the turbine shaft, bearing housing, turbine wheel and blades,
are also disclosed.
BACKGROUND ART
The development and use of
transport fuels based on renewable resources has increased over recent decades
due to worries over fossil fuel depletion (“peak oil”), global warming and
energy security.
ED95 is an ethanol-based
fuel for use in compression ignition engines, and as such is an environmentally
sustainable alternative to diesel. ED95 comprises about 95 percent ethanol,
together with further additives such as ignition improver, corrosion inhibitor,
surfactant, denaturant and colourant. The ignition improver is commonly a
polyethylene glycol (PEG) derivative, such as Beraid 3555.
The use of ED95 in a
vehicle is not without problems, however. During use, non-combusted fuel may
reach the turbocharger in the exhaust system of the vehicle. This non-combusted
fuel may cause sticky deposits on components of the turbo, including the
turbine shaft and bearing housing. These deposits are primarily composed of the
PEG ignition improver present in the ED95, which is hydrophilic and has a high
molecular weight. The problem is exasperated by the formation of an oxide layer
on the surface of the turbo components due to oxidation of the component by hot
combustion gases. This oxide layer is also hydrophilic, meaning that it has an
increased affinity for the hydrophilic PEG ignition improver, leading to
increased deposits. Eventually, the build-up of such deposits may lead to the
turbocharger malfunctioning and needing to be replaced, which is costly.
TECHNICAL SOLUTION
Residues may be prevented from depositing on surfaces of the
turbocharger by coating the appropriate turbocharger surfaces using a thermal
barrier coating (TBC). A TBC is a thermally insulating coating that can sustain
an...