11
March
2005
Alan
Stout
Fuel
Emissions
Laboratory/
OAR
2565
Plymouth
Road
Ann
Arbor,
MI
48105
Subject:
Regulation
of
Nonroad
Large
Spark
Ignited
Engines
Derived
from
Diesels
Dear
Alan,

Below
are
details
of
Cummins
recommendation
for
EPA
to
regulate
on­
highway
and
nonroad
engines
consistently
when
considering
spark
ignited
engines
that
are
derived
from
diesels.
Cummins
encourages
EPA
to
make
the
necessary
changes
in
the
technical
amendment
final
rule.

Please
let
me
know
if
you
have
any
questions
or
would
like
additional
information.

Sincerely,

Todd
R.
Hendrickson
Product
Environmental
Management
Off­
Highway
Applications
Manager
Cummins
Inc.
todd.
r.
hendrickson@
cummins.
com
812­
377­
4235
Cummins
Position
on
Nonroad
Spark
Ignited
Engines
Derived
from
Diesels
10
March
2005
Recommendation:
Cummins
recommends
that
the
nonroad
CI
regulations
of
40CFR89
and
40CFR1039
apply
to
nonroad
spark
ignited
engines
(
natural
gas
and
propane)
that
are
derived
from
diesels.
The
applicability
of
these
regulations
or
the
provisions
of
40CFR1048.620
should
be
modified
accordingly
as
part
of
the
ongoing
technical
amendment
rulemaking.

Issue:
Significant
inconsistencies
exist
in
how
EPA
regulates
spark
ignited
engines
that
are
derived
from
diesels.
On­
highway
applications
and
nonroad
applications
may
be
treated
similarly
by
ARB.
In
California,
nonroad
engine
certification
may
follow
the
same
basic
applicability
guidelines
as
on­
highway
engines.
For
EPA,
however,
this
is
not
the
case.

On­
highway
­
EPA:
For
on­
highway
applications,
SI
engines
derived
from
CI
engines
are
regulated
by
EPA
under
the
diesel
requirements
of
40CFR86.
SI
engines
derived
from
diesels
are
treated
as
diesels
and
SI
engines
derived
from
gasoline
engines
are
treated
as
Otto
cycle
engines.
ARB:
ARB
also
regulates
these
engines
in
this
manner.

Nonroad
­
EPA:
For
nonroad
engines,
all
SI
engines
are
regulated
by
EPA
under
the
large
spark
ignited
requirements
of
40CFR1048.
Provisions
for
these
engines
to
be
regulated
under
the
nonroad
diesel
rule,
40CFR89,
exist
only
for
natural
gas
engines
greater
than
250kW,
as
specified
in
40CFR1048.620.
No
other
provisions
exist
for
considering
these
engines
under
40CFR89.
ARB:
ARB
also
has
a
nonroad
spark
ignited
rule,
but
the
provisions
of
the
ARB
diesel
rule
allow
all
spark
ignited
engines
which
are
derived
from
diesels
to
be
considered
under
diesel
rule
(
references
section
2420).

Justification:

The
justification
for
the
above
recommendation
is
based
on
the
following:

1.
SI
engines
(
natural
gas
and
propane)
derived
from
diesels
compete
with
diesel
engines.
The
purchasers
of
these
engines
require
the
ruggedness
of
a
diesel
and
the
low
emissions
of
a
natural
gas
or
propane
engine.
Natural
gas
and
propane
engines
derived
from
gasoline
engines
compete
with
gasoline
engines.
Therefore,
competition
between
diesel­
derived
and
gasoline­
derived
SI
natural
gas
and
propane
engines
is
not
an
issue.

2.
The
duty
cycles
of
SI
engines
derived
from
diesels
are
similar
to
their
diesel
counterparts.
The
8­
mode
test
cycle
in
40CFR89
is
more
appropriate
for
these
engines
than
the
7­
mode
test
cycle
specified
in
40CFR1048.
The
8­
mode
test
cycle
has
significant
weighting
at
rated
speed
and
intermediate
speed,
while
the
7­
mode
test
primarily
considers
emissions
at
intermediate
speed.
The
7­
mode
test
is
not
representative
of
the
duty
cycles
of
SI
engines
derived
from
diesels.
3.
The
useful
lives
of
SI
engines
derived
from
diesels
is
similar
to
their
diesel
counterparts
and
not
the
shorter
useful
lives
of
gasoline
engines.

4.
The
applicability
of
the
regulations
should
be
consistent
for
on­
highway
and
nonroad
engines.

Conclusion:

Regulating
nonroad
SI
engines
that
are
derived
from
diesels
is
not
only
consistent
with
the
EPA's
treatment
of
on­
highway
engines,
but
it
is
also
technically
justified.

The
nonroad
regulations
should
be
modified
to
eliminate
the
current
inconsistency
in
applying
the
regulations.
This
can
be
accomplished
by
modifying
the
applicability
of
the
nonroad
CI
rules
40CFR89
and
40CFR1039,
or
by
expanding
the
applicability
of
40CFR1048.620
in
the
LSI
rule.
40CFR1048.620
would
need
to
be
modified
to:
a)
include
both
natural
gas
and
propane
engines,
b)
include
all
ratings
regardless
of
maximum
rated
power,
c)
include
exemptions
for
engines
certified
under
40CFR86
