U.S. patent application number 10/080862 was filed with the patent office on 2003-05-22 for clean-burning mtbe-free gasoline fuel.
This patent application is currently assigned to Fortum Oyj. Invention is credited to Ignatius, Jyrki, Jakkula, Juha, Nasi, Risto, Rautiola, Aimo.
Application Number | 20030094397 10/080862 |
Document ID | / |
Family ID | 26764043 |
Filed Date | 2003-05-22 |
United States Patent
Application |
20030094397 |
Kind Code |
A1 |
Ignatius, Jyrki ; et
al. |
May 22, 2003 |
Clean-burning MTBE-free gasoline fuel
Abstract
The present invention provides a new gasoline fuel composition,
having in combination an octane value (R+M)/2 of at least 85; an
aromatics content less than 25 vol. %; and a water-soluble ethers
content of less than 1 vol. %. The composition has a content of
olefins, at least 10 % of which is formed by heavy olefins having a
boiling point above +90 "C. In particular, the composition contains
up to 40 % olefins, and it contains less than 6 vol.-% of light
olefins having a boiling point below +90.degree. C., and at least 1
vol.-% heavy branched olefins having a boiling point above
+90.degree. C. Reductions in emissions of pollutants can be
obtained by introducing into an automotive engine an unleaded
gasoline having a composition according to invention, combusting
the unleaded gasoline in said engine; introducing at least some of
the resultant engine exhaust emissions into the catalytic
converter; and discharging emissions from the catalytic converter
to the atmosphere.
Inventors: |
Ignatius, Jyrki; (Porvoo,
FI) ; Jakkula, Juha; (Kerava, FI) ; Nasi,
Risto; (Ostersundom, FI) ; Rautiola, Aimo;
(Klaukkala, FI) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
Fortum Oyj
Espoo
FI
|
Family ID: |
26764043 |
Appl. No.: |
10/080862 |
Filed: |
February 22, 2002 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60312410 |
Aug 15, 2001 |
|
|
|
Current U.S.
Class: |
208/16 |
Current CPC
Class: |
C10L 1/1852 20130101;
C10L 1/023 20130101; C10L 1/14 20130101; C10L 10/02 20130101; C10L
1/1824 20130101; C10L 10/10 20130101; C10L 1/1608 20130101; C10L
1/1616 20130101 |
Class at
Publication: |
208/16 |
International
Class: |
C10L 001/04 |
Claims
1. A gasoline fuel composition, having in combination an octane
value (R+M)/2 of at least 85; an aromatics content less than 25
vol-%; a water-soluble ethers content less than 1 vol-%; a 10% D-86
distillation point no greater than +150.degree. F. (65.6.degree.
C.); a 50% D-86 distillation point no greater than +230.degree. F.
(110.degree. C.); a 90% D-86 distillation point no greater than
+375.degree. F. (190.6.degree. C.); Reid Vapor Pressure of less
than 9.0 psi (62 kPa); a content of light olefins, with a boiling
point below +90.degree. C., of less than 6 vol. %; and a combined
content of trimethylpentenes, trimethylhexenes and
trimethylheptenes greater than 1 vol. %.
2. The gasoline fuel composition according to claim 1, having
combined content of trimethylpentenes, trimethylhexenes and
trimethylheptenes of 2 to 30 vol. %.
3. The gasoline fuel composition according to claim 2, having a
content of isooctene in the range of 5 to 20 vol. %.
4. The gasoline fuel composition according to claim 1, further
containing 0.1 to 20 vol. % of isoparaffines.
5. The gasoline fuel composition according to claim 4, wherein the
total content of isoolefins and isoparaffins is 2 to 40 vol. %.
6. The gasoline fuel composition according to claim 1 wherein the
total content of olefins is less than 20 vol. %.
7. The gasoline fuel composition according to claim 1, further
having an ethanol content of 0.01 to less than 6 vol. %.
8. The gasoline fuel composition according to claim 1, wherein the
concentration of oxygen is 0.1 to 5 mass %.
9. A gasoline fuel composition, having in combination an octane
value (R+M)/2 of at least 85; an aromatics content less than 25
vol. %; and a water-soluble ethers content of less than 1 vol. %;
wherein said composition has a content of olefins, at least 10% of
which is formed by heavy olefins having a boiling point above
+90.degree. C.
10. A gasoline fuel composition, having in combination an octane
value (R+M)/2 of at least 85; an aromatics content less than 25
vol. %; and a water-soluble ethers content of less than 1 vol. %;
wherein said composition contains up to 40% olefins, and it
contains less than 6 vol.-% of light olefins having a boiling point
below +90.degree. C., and at least 1 vol.-% heavy branched olefins
having a boiling point above +90.degree. C.
11. A method of reducing the emissions of an automotive engine of
one or more pollutants selected from the group consisting of CO,
NOx, particulates and hydrocarbons compared to combusting CARB 2
fuel, comprising a) introducing into said automotive engine an
unleaded gasoline according to claim 1 or 10 b) combusting the
unleaded gasoline in said engine; c) introducing at least some of
the resultant engine exhaust emissions into the catalytic
converter; and d) discharging emissions from the catalytic
converter to the atmosphere.
12. The method according to claim 11, wherein the gasoline further
contains 0.01 to 6 vol. % ethanol.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to gasoline fuels. In
particular, the present invention concerns gasoline fuels free from
or having only a low content of water-soluble ethers. The present
invention also relates to a method of reducing the emissions of one
or more pollutants, selected from the group consisting of CO,
NO.sub.x, particulates and hydrocarbons, from an automotive
engine.
[0003] 2. Description of Related Art
[0004] Currently large amounts of water-soluble ethers (e.g. MTBE,
methyl tert-butyl ether) are used by petroleum refiners as gasoline
components for formulating gasoline products, which, upon
combustion in automotive engines, will give rise to low exhaust
emissions of harmful pollutants, such as carbon monoxide and
nitrogen oxides. To mention an example, present-day Californian
grade gasoline, abbreviated CARB II (California Phase II gasoline),
contains about 12 vol.-% MTBE and it essentially meets the
specifications set by the California Air Resources Board. It has an
oxygen content of about 2%. However, MTBE is water-soluble and
biologically very stable, and it may have a tendency to accumulate
in groundwater. Thus, the use of water-soluble ethers, such as
MTBE, as a component of gasoline fuels will have to be avoided in
the future in California and alternative solutions should be found
to provide clean-burning high-performance fuels for automotive
engines.
SUMMARY OF THE INVENTION
[0005] It is an aim of the present invention to eliminate the
disadvantages of the prior art and to provide a novel gasoline
fuel, which is essentially free from water-soluble ethers while
still meeting stringent exhaust emission limits.
[0006] It is another object of the invention to provide a method of
reducing the emissions of an automotive engine of one or more
pollutants selected from the group consisting of CO, NOx,
particulates and hydrocarbons compared to combusting a CARB II
fuel.
[0007] These and other objects of the invention and benefits
associated therewith will become evident from the following
detailed description of the invention.
[0008] The present invention is based on the finding that when
gasoline fuels without a significant amount of water soluble ethers
are produced by blending several hydrocarbon-containing streams
together so as to formulate a gasoline product suitable for
combustion in a gasoline spark-ignition internal combustion engine,
reductions in the emissions of one or more pollutants selected from
the group consisting of CO, NOx, particulates and hydrocarbons upon
combustion of the gasoline product in such an engine system can be
attained by controlling certain chemical and/or physical properties
of said gasoline product.
[0009] It is well known that olefins, primarily light olefins and
in particular tertiary olefins, contribute to the formation of
ozone in the atmosphere. However, the relative ozone formation
potential of heavy olefins, with a boiling point greater than about
90.degree. C. (194.degree. F.), is very low.
[0010] We have found that heavier olefins have a positive effect on
the tail pipe emissions and, therefore, it is advantageous to
control and minimize the amount of light olefins only in automotive
gasoline.
[0011] According to the present invention, the content of light
olefins, having a boiling point below +90.degree. C. (194.degree.
F.), in particular below 85.degree. C. (185.degree. F.), should be
less than about 10 vol.-%, preferably less than 6 vol.-% of the
gasoline composition. These olefins are made up by C.sub.2-C.sub.6
hydrocarbons. By contrast, the content of heavy olefins having a
boiling point above +90.degree. C., preferably above +95.degree. C.
(203.degree. F.), can be more than 1 vol.-%, preferably 2 vol.-% or
more, up to about 30 vol.-%. Suitable heavy olefins contain 8
carbon atoms or more and they are preferably branched. Particularly
preferred examples include branched isoolefins containing 8 to 12
carbon atoms, such as trimethylpentenes (isooctenes),
trimethylhexenes and trimethylheptenes.
[0012] In the fuel, the heavy olefins can used together with
paraffines, in particular isoparaffines, such as isooctane, and
with alcohols, such as ethanol or methanol.
[0013] Thus generally, the invention provides a gasoline fuel
composition, having in combination
[0014] an octane value (R+M)/2 of at least 85;
[0015] an aromatics content less than 25 vol. %; and
[0016] a water-soluble ethers content of less than 1 vol. %.
[0017] The composition has a content of olefins, at least 10% of
which is formed by heavy olefins having a boiling point above
+90.degree. C. In particular, the composition contains up to 40%
olefins, and it contains less than 6 vol.-% of light olefins having
a boiling point below +90.degree. C., and at least 1 vol.-% heavy
branched olefins having a boiling point above +90.degree. C."
[0018] According to an exemplifying embodiment, the present
invention concerns an unleaded, clean-burning gasoline fuel with a
low content of water-soluble ethers, suitable for combustion in a
spark-ignition internal combustion engine and especially in a
gasoline direct injection, lean-burning automotive engine having
the following properties:
[0019] an octane value (R+M)/2 of at least 85;
[0020] an aromatics content less than 25 vol-%;
[0021] a water-soluble ethers content less than 1 vol-%;
[0022] a 10% D-86 distillation point no greater than +150.degree.
F. (65.6.degree. C.);
[0023] a 50% D-86 distillation point no greater than +230.degree.
F. (110.degree. C.);
[0024] a 90% D-86 distillation point no greater than +375.degree.
F. (190.6.degree. C.);
[0025] Reid Vapor Pressure of less than 9.0 psi (62 kPa);
[0026] a light olefins content, with boiling point below
+90.degree. C., less than 6 vol-%; and
[0027] a combined content of trimethylpentenes, trimethylhexenes
and trimethylheptenes greater than 1 vol. %.
[0028] Reductions in emissions of one or more pollutants selected
from the group consisting of CO, NO.sub.x, particulates and
hydrocarbons compared to combusting a CARB II fuel can be obtained
by
[0029] a) introducing into said automotive engine an unleaded
gasoline having a composition according to any of the above defined
gasolines:
[0030] b) combusting the unleaded gasoline in said engine;
[0031] c) introducing at least some of the resultant engine exhaust
emissions into the catalytic converter; and
[0032] d) discharging emissions from the catalytic converter to the
atmosphere.
[0033] Considerable advantages are obtained by the present
invention. As will appear from the results presented below, MTBE
and similar water-soluble alkyl ethers can be replaced by an
increased content of heavier olefins, in particular isoolefins,
such as isooctene, in CARB gasoline, without any backsliding of
exhaust gas quality. On the contrary, compared to an
MTBE-containing fuel, when combusted in a spark ignition internal
combustion engine, and particularly in a gasoline direct-injection,
lean-burning automotive engine, the present fuels will produce a
relatively low amount of gaseous pollutants, in particular one or
more of NO.sub.x CO, particulates and unburned or incompletely
burned hydrocarbons. Further, there would appear to be a reduction
of fuel consumption.
[0034] Based on a study commissioned by the EU, there will be no
ban on water-soluble alkyl ethers in gasoline in Europe in the
foreseeable future, at least within the next 10 or 20 years. It
should be pointed out that the present gasoline composition can
also be easily converted for use with alkyl ethers by including a
desired amount of an alkyl ether as an oxygenate component instead
of an alcohol or in addition to that alcohol. In such gasolines,
the total concentration of ether+alcohol can be up to 8 vol. %
giving rise to an oxygen concentration of 1 to 3 vol. % Next, the
invention will be examined more closely with the aid of the
following detailed description with reference to the attached
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1 shows in the form of a bar chart the total
hydrocarbon emissions of six different test cars for six different
gasoline compositions;
[0036] FIG. 2 shows the corresponding bar chart of carbon monoxide
emissions;
[0037] FIG. 3 shows the corresponding bar chart of nitrogen oxide
(NOx) emissions;
[0038] FIG. 4 shows the corresponding bar chart of carbon dioxide
emissions;
[0039] FIG. 5 shows the corresponding bar chart of combined HC and
NOx emissions;
[0040] FIG. 6 shows the corresponding bar chart of particulate
matter emissions; and
[0041] FIG. 7 shows the corresponding bar chart of gasoline
consumption.
[0042] FIG. 8 shows in the form of bar chart the change (%) of the
content of methane in exhaust gases compared to fuel RFG for two (E
and F) cars of the set of test cars.
[0043] FIG. 9 shows the corresponding bar chart of 1,3-butadiene
content of exhaust gases.
[0044] FIG. 10 shows the corresponding bar chart of benzene content
of exhaust gases.
[0045] FIG. 11 shows the corresponding bar chart of BTEX compaunds
content of exhaust gases.
[0046] FIG. 12 shows the corresponding bar chart of formaldehyde
content of exhaust gases.
[0047] FIG. 13 shows the corresponding bar chart of acetaldehyde
content of exhaust gases.
[0048] FIG. 14 shows content of polyaromatichydrocarbons (PAH14;
EPA PAH) of the particulate matter of the exhaust gases from the
two test cars (E and F).
[0049] FIG. 15 shows the amount of the semivolatile part of
particulate matter above.
[0050] FIG. 16 shows the effect of particulate matter above on the
AMES-mutagenicity (rev/mg).
[0051] FIG. 17 shows the effect of particulate matter above on the
AMES-mutagenicity (krev/km).
DETAILED DESCRIPTION OF THE INVENTION
[0052] The present invention relates to a low-emission, gasoline
fuel composition, which is essentially free from water-soluble
ethers typically used for increasing the octane number of the fuel
and for improving the combustion properties thereof. The properties
referred to above and in the following are determined by standard
test methods outlined in Table 3. Thus, for example, distillation
cuts are determined by ISO 3405 (corresponds to ASTM D86), and
vapour pressure by EN 13016
[0053] The ether content of the present fuel compositions is 1
vol.-% or less, preferably less than 0.6 vol.-%, in particular less
than about 0.4 vol.-%. Thus, the gasoline composition is
"essentially free from water-soluble ethers".
[0054] Typically, the fuel has an octane value (R+M)/2 of at least
85, preferably at least 92, in particular at least 95.
[0055] The aromatics content is less than 25 vol. %. It has a total
olefins content of more than about 7 vol.-%, typically less than
about 40 vol.-%. A considerable part of the olefins are heavy
olefins, such as C.sub.7+olefins. When the total amount is about 7
vol. %, at least about 15% of the olefins are heavy, and when the
total content is 20 to 30 vol.-%, the heavy olefins make up about
70 vol.-% or more.
[0056] It is preferred to limit the total concentration of olefins
to about 20 vol.-%.
[0057] The preferred heavy olefins are isoolefins comprising 8 to
14 carbon atoms. In particular, the heavy olefins are selected from
the group of branched octenes, nonenes and decenes. The following
examples can be mentioned: trimethylpentenes, trimethylhexenes and
trimethylheptenes. The combined content these compounds is 2 to 30
vol. %, and the isooctane, which represents a particularly
preferred embodiment, typically stands for a content of 5 to 20
vol. %.
[0058] In addition to isoolefins, the present gasoline fuel
composition can contain various amounts of paraffines, in
particular isoparaffines. The latter are incorporated in amounts of
0.1 to 20 vol.-% preferably about 1 to 15 vol.-%. According to a
preferred embodiment, the total content of isoolefins and
isoparaffins is about 2 to 40 vol.-%. Isooctane is a typical
isoparaffine, which can be used in up to 20 vol.-%.
[0059] The present fuel can also contain various oxygenates, such
as alkanols (alcohols). As specific examples, ethanol and methanol
can be mentioned. Ethanol-containing compositions contain ethanol
in an amount of 0.01 to less than 6 vol.-%. The same concentration
range is applicable to methanol. The alkanols can be derived from
renewable sources.
[0060] By limiting the total concentration of olefins and the
maximum concentration of light olefins, and further by using
oxygenates it is possible to maintain good combustion properties of
the gasoline while reducing emissions.
[0061] The concentration of oxygen in the fuel is generally about
0.1 to 5 mass %. Typically, the amount of alkanols is sufficient to
provide the gasoline composition with an oxygen content of about 1
to 4 mass-%.
[0062] A fuel according to the present invention exhibits the
following characteristics:
[0063] a 10% D-86 distillation point no greater than +150.degree.
F. (65.6.degree. C.), in particular less than 140.degree. F.
(60.degree. C.);
[0064] a 50% D-86 distillation point no greater than +230.degree.
F. (110.degree. C. ), in particular less than 220.degree. F.
(104.4.degree. C.);
[0065] a 90% D-86 distillation point no greater than +375.degree.
F. (190.6.degree. C.), in particular less than 370.degree. F.
(187.8.degree. C.); and
[0066] a Reid Vapor Pressure less than 9.0 psi (62 kPa), in
particular less than 8.5 psi (58.6 kPa).
[0067] Based on experimental data, the particulate matter emissions
were 50% lower than those of a conventional CARB II fuel, and the
emissions of THC, NOx, CO and CO.sub.2 were on the same level or
lower as for CARB II fuels.
[0068] The experimental results shown below indicate that it is
fully possible to provide gasoline compositions which are free from
water-soluble and which, nevertheless, meet even stringent
requirements for low emissions, by increasing the concentration of
heavy olefins and by simultaneously reducing the concentration of
light olefins.
[0069] The following, non-limiting example will elucidate the
invention:
EXAMPLE
[0070] The composition of the gasoline is basically determined by
the CARB specification. The present invention provides for a
modification of that specification by the combined use of heavy
olefins and isoparaffines, in particular isooctene and isooctane,
optionally with oxygenates, in particular ethanol.
[0071] The exhaust emission tests were carried out with six
different fuels. The fuels and their compositions are shown in
Table 1 below:
1TABLE 1 Compositions of Test Fuels TEST Aromatics FUELS Isooctane
Isooctene NExTAME Ethanol MTBE Oxygen w-% Olefins vol-% vol-% RFG X
X 2 15 35 ref CARB II X 2 5 25 ref CARB III IO X X 2 5 25 CARB III
IOE X X X 2 15 25 IsoOkt X 5 25 IsoOkte X X 15 25 In the above
table, the following abbreviations are used: RFG Reformulated
gasoline, Porvoo refinery sales grade into Finnish markets, Fulfils
EU 2005 requirements, our reference in all of our measurements CARB
II Californian grade gasoline containing MTBE, California Phase II
gasoline (MTBE gasoline) that almost meets the specifications set
by the California Air Resources Board CARB III IO Californian grade
gasoline containing ethanol and isooctane, Future California Phase
III gasoline without MTBE, but containing oxygen CARB III IOE
Californian grade gasoline containing ethanol, isooctane and
isooctene, Future California Phase III gasoline without MTBE, but
containing oxygen, like CARB III IO, but 10 vol-% of paraffins and
isoparaffins have been replaced by heavy olefins (isooctene) IsoOkt
Like Californian grade gasoline without any oxygenates, isooctane
gasoline where the MTBE has been replaced with isooctane IsoOkte
Like Californian grade gasoline without any oxygenates, isooctane
gasoline where the MTBE has been replaced with isooctane, like
IsoOkt, but 10 vol-% of paraffins and isoparaffins have been
replaced by heavy olefins (isooctane)
[0072] In RFG, the concentration of TAME was 18 vol.-% and of MTBE
5 vol.-%. In CARB II, the concentration of MTBE was 12 vol.-%.
[0073] In the rest of the fuel compositions, the concentration of
isooctane was 11 vol.-% and in CARB III IO and IsoOkte, the
concentration of isooctane was 10 vol. %.
[0074] The properties of the isooctane and isooctene components,
obtained from the Fortum NExOCTANE pilot plant in Porvoo, Finland,
are given in Table 2.
2TABLE 2 Properties of isooctane and isooctane components. Property
Method Isooctane Isooctane RON ISO 5164 100.5 101.6 MON ISO 5163
98.3 84.6 Vapor pressure [kPa] 15.9 14 Density [kg/m3] 701 729 T10
distillation point [.degree. C.] ASTM D86 98 102 T50 distillation
point [.degree. C.] ASTM D86 100 105 T90 distillation point
[.degree. C.] ASTM D86 119 117 Olefin content, GC [% by volume] 0.5
97 Aromatics content, GC [% by 0 0 volume] Saturates, GC [% by
volume] 99.5 0
[0075]
3TABLE 3 Properties of test fuels CARB CARB CARB Code RFG II III IO
III IOE IsoOkt IsoOkte Density ISO 12185 kg/m.sup.3 766 742 745 745
736 737 at +15.degree. C. Sulphur ASTM ppm 25 10 11 12 10 9 D 3120
Vapour EN 13016 kPa 62 59 61 63 60 61 Pressure FIA-O ISO 3837 Arom
Vol-% 37 27 25 25 25 26 Olef Vol-% 13 5 4 14 3 14 Paraf + Naph
Vol-% 38 58 65 55 72 60 Oxygenates Vol-% 12 11 5 6 0 0 Total 100
100 100 100 100 100 C/H-ratio 6.93 6.49 6.45 6.56 6.50 6.59 Content
of NMR mass-% 12.70 13.50 13.60 13.50 14.00 13.70 Hydrogen Benzene
GC mass-% 0.70 0.37 0.35 0.39 0.34 0.37 EtOH AED Vol-% 5.46 5.36
0.00 0.00 TAME AED Vol-% 5.55 0.02 0.02 0.00 0.00 0.00 MTBE AED
Vol-% 4.48 11.09 0.02 0.03 0.03 0.04 Other Vol-% 0.04 0.00 0.00
0.00 Oxygenates Distillation ISO 3405 IBP .degree. C. 33.4 29.3
35.4 32.9 28.5 33.0 05 til-% .degree. C. 45.0 42.4 45.0 47.4 43.4
45.6 10 til-% .degree. C. 54.0 50.5 51.8 52.4 53.6 54.2 20 til-%
.degree. C. 69.3 59.5 59.1 59.3 68.5 67.7 30 til-% .degree. C. 81.6
68.0 66.6 67.2 81.6 79.8 40 til-% .degree. C. 92.7 77.5 87.4 85.7
92.7 91.4 50 til-% .degree. C. 103.0 88.7 101.0 98.9 101.3 100.4 60
til-% .degree. C. 114.5 101.8 108.3 106.6 108.1 107.3 70 til-%
.degree. C. 126.7 114.8 116.4 114.4 115.2 114.5 80 til-% .degree.
C. 140.4 127.8 127.7 125.2 126.3 125.5 90 til-% .degree. C. 155.3
147.5 148.5 146.3 147.7 146.8 95 til-% .degree. C. 165.3 159.6
159.9 158.3 160.5 161.0 FBP .degree. C. 196.6 189.7 190.1 187.6
189.6 190.7
[0076] Emissions were measured at 22.degree. C. temperature for 6
vehicles using the European cycle for year 2000 (ECE+EUDC). Five of
the vehicles have 4-cylinder, 16-valve engines equipped with multi
point fuel injection (MPI) and a three-way catalytic converter
(TWC). The swept volume of these vehicles A, B, C, D and F was form
1.3 liter to 2.0 liter. One vehicle (E) has the engine with six
cylinder and the swept volume of 3.3 liters. Also this vehicle was
equipped with multi point fuel injection (MPI) and a three-way
catalytic converter (TWC
[0077] EMISSION TESTING--Exhaust emissions and fuel consumption of
the vehicles were measured on a chassis dynamometer using the
current European test cycle according to 70/220/EEC and its
amendments. The test equipment used for exhaust dilution,
collection of samples and analysis of samples are in compliance
with the specifications of US EPA and directive 70/220/EEC and its
amendments.
[0078] SAMPLING AND ANALYSES OF PARTICULATE AND SEMIVOLATILE
MATTER--Particulates were collected at Fortum using a high capacity
system and at the Technical Research Centre of Finland (VTT) using
a similar system. The test procedure, sampling and analyses of
particulate and semi-volatile matter was performed in a similar way
as described by Kokko et al. [Kokko, J., Rantanen, L., Pentikinen,
J., Honkanen, T., Aakko, P., and Lappi, M., Reduced Particulate
Emissions with Reformulated Gasoline, SAE Technical Paper
2000-01-2017, 2000]. Sampling and analytical procedures for the
particulate and semi-volatile phases at both Fortum and VTT
laboratories are briefly described in Lappi, M., Harmonisation of
measuring methods of unregulated exhausts from passenger cars.
Results of the Round-robin tests. Final report. VTT Energy Engine
Technology. Mobile Research Program. Project 232T. March 1999. 50
p.+App. 119 p.
[0079] THC Emissions--The total hydrocarbon emissions are presented
in FIG. 1. The THC emissions from the vehicles using a catalytic
converter are with near all of the vehicles tested lower with the
gasolines according to the present invention than with the other
gasolines.
[0080] CO Emissions--Values presented in FIG. 2 show that, compared
to CARB II, the carbon monoxide emissions are lower for five
vehicles for CARB III IOE, whereas they are somewhat higher for
ISO-OKTE. This confirms that the effect of oxygen in gasoline can
be significant when reducing CO emissions especially in vehicles
without closed loop fuel control systems.
[0081] NO.sub.x Emissions--Generally, gasoline with oxygenates
slightly increases NO.sub.x emissions, and this was also found to
be the case in this study, but lower for the gasolines according to
the present invention compared to CARB II with all cars tested.
[0082] CO.sub.2 Emissions and fuel consumption--The carbon dioxide
emissions and gasoline consumption of the test vehicles are
presented in FIGS. 4 and 7. CO.sub.2 emissions from all the
gasolines are almost equal and the possible differences are within
the confidence interval. All the differences fall within the
confidence interval. Fuel consumption for the fuels with no
oxygenates were lower than with oxygenates as expected.
[0083] Non-controlled emissions--With the two test cars (E and F)
also the amount of so called non-controlled exhaust emissions were
measured (FIGS. 8 to 13). From the figures can be seen that the
results are more depending on the car measured than on the fuel
tested. And no big differences cannot be seen.
[0084] PARTICULATE MASS EMISSIONS--The average particulate mass
emissions at 22.degree. C. with the two fuels and all vehicles are
given in FIG. 6. Results are presented as average values derived
from three or four tests on each fuel. Confidence intervals for
these mean values are shown at the 95% level. With catalyst
equipped vehicles the amount of particulate mass collected on the
filters is very small compared to the weight of blank filters and
thus the standard deviation of the results is rather high.
Therefore the confidence intervals are quite large. Nevertheless,
the gasolines according to the present invention have extremely low
particulate mass emissions compared to all other gasolines,
including CARB II. The toxic and mutagenic promerties of the
particulate matter of the exhaust gases from the two test cars are
represented in FIGS. 14 to 17. It can be seen that toxicity and the
mutagenicity of the particulates with the fuel of the present
invention were lower when compared to CARB II with all cars
tested.
[0085] As the above test results, it is fully possible to replace
MTBE in gasoline with heavy olefins without impairing the air
quality of exhause gases.
* * * * *