MEMORANDUM
DATE:
December,
2005
SUBJECT:
Discussions
Regarding
Secondary
Air
System
Usage
at
20
°
F
with
European
Automotive
Manufacturers
and
Suppliers
of
Secondary
Air
Systems
FROM:
Antonio
Fernandez,
Engineer
Assessment
and
Standards
Division
TO:
Docket
EPA­
HQ­
OAR­
2005­
0036
We
contacted
representatives
of
several
European
automotive
manufacturers
to
obtain
additional
information
on
the
feasibility
of
utilizing
these
systems
at
temperatures
below
freezing.
The
automotive
manufacturers
have
indicated
that
many
of
their
vehicles
sold
in
the
United
States
(
US)
that
are
equipped
with
secondary
air
systems
do
in
fact
operate
at
20
°
F
due
to
the
existing
European
­
6
°
C
(
20
°
F)
emission
requirements.
The
engineering
staff
at
these
companies
is
familiar
with
the
operational
requirements
of
the
secondary
air
injection
system
at
temperatures
below
freezing.
While
the
vehicles
may
have
originally
been
equipped
with
a
secondary
air
system
to
comply
with
emissions
at
75
°
F,
the
systems
have
been
adapted
for
use
at
other
cold
start
temperatures
including
20
°
F.
European
manufacturers
indicated
that
not
all
of
their
vehicles
have
required
secondary
air
injection
systems
to
comply
with
current
US
and
or
European
emission
standards
including
the
­
6
°
C
(
20
°
F)
European
requirement.
These
manufacturers
indicated
that
with
proper
secondary
air
system
design
and
integration
into
the
vehicle
emission
control
system,
no
operational
issues
have
been
observed
in
the
field
attributed
to
the
use
of
secondary
air
injection
at
20
°
F.

We
also
contacted
sales
and
applications
engineering
representatives
from
the
major
manufacturers
of
the
secondary
air
injection
systems
and
individual
components
of
these
systems.
These
manufactures
supply
the
majority
of
secondary
air
systems
or
individual
components
of
these
systems
to
automotive
manufacturers
for
vehicles
sold
throughout
the
world.
The
manufacturers
included:

­
Borg
Warner
­
Bosch
­
Denso
­
Pierburg
In
discussions
with
these
suppliers
about
the
operational
capabilities
of
the
secondary
air
systems
or
components
of
these
systems
at
cold
starts
below
freezing,
no
manufacturer
stated
that
their
systems
or
components
lacked
the
ability
to
operate
at
temperatures
below
freezing.
In
fact,
some
mentioned
that
they
test
and
perform
durability
at
temperatures
well
below
freezing
in
addition
to
supplying
secondary
air
systems
or
components
to
European
market
sold
vehicles
that
currently
operate
these
systems
at
­
7
°
C
(
20
°
F)
to
meet
the
European
cold
emission
requirements.
Consistent
with
comments
from
the
European
automotive
manufacturers,
these
suppliers
indicated
that
proper
secondary
air
system
design
and
implementation
is
a
requirement
for
proper
system
operation
and
durability.
Issues
such
as
water
condensation
resulting
in
ice
formation
in
the
secondary
air
system
have
been
addressed
through
proper
secondary
air
injection
system
integration
into
the
vehicle
such
as:

­
Providing
clean
dry
air
feed
to
the
pump
from
the
air
cleaner
assembly.
­
Locating
and
routing
of
the
pump
and
air
lines
to
prevent
water
traps.
­
Properly
selecting
and
locating
the
air
control
valve
to
prevent
exhaust
condensation
issues.

The
careful
consideration
of
these
design
criteria
when
implementing
a
secondary
air
system
has
resulted
in
robust
operation
of
the
systems
at
start
temperatures
including
20
°
F
as
demonstrated
by
the
European
manufacturers.
