Reference 1

General Resources Energy Investigation Committee, Energy Savings Standards Section,
Automobile Standards Judging Subcommittee
LPG Car Fuel Efficiency Standards Evaluation Group
Final ReportThis subcommittee and evaluation group convened discussions of items necessary toevaluate standards of LPG (liquid petroleum gas) car manufacturers and importers(hereinafter manufacturers) concerning energy consumption efficiency (fuel efficiency) of
LPG cars. The final report is as below.
1. Target Scope (see Attachment 1)
LPG passenger cars that have received type designation under the Road Transport and Motor
Vehicle Law (1951, Law No. 185) Article 75.1.

2. Prerequisite items, etc. for judgment standards of manufacturers, etc.
(1) Target fiscal year (see Attachment 2)
FY2010(2) Energy consumption efficiency (fuel efficiency) measurement methods (see Attachment 3)
Values shall be indicated in kilometers driven per one liter of fuel in the 10-15 Japanese test
mode with values (inspection values) measured by the Minister of the Ministry of Land,
Infrastructure and Transport for the type designation of cars.
(3) Classifications and Target Standard Values (see Attachments 4, 5)
For passenger cars shipped in Japan in the target year, LPG passenger car manufacturers, etc.
shall not fall below the standard target values for energy consumption efficiency (fuelefficiency) measured by (2) and weighted and averaged by shipped units in each classificationin the following table.
Classification(Vehicle Curb
Weight) (kg)
Target Standard
Value (km/l)

-703

703
-827

828
-1,015

1,016-1,265

1,266-1,515

1,516-1,765

1,766-2,0152,016-2,2652,266-

15.9

14.1

13.5

12.0

9.8

7.9

6.7

5.9

4.8

(Reference)
The target standard values are set as above, and assuming the ratio of shipped units is the samefor FY2010 as it was for FY2001, the improvement ratio of fuel efficiency is anticipated toincrease from FY2001 actual performance values to 11.4%. However, if compared with FY1995,
the standard fiscal year used for comparison concerning improvements in fuel efficiency
standards for cars in broad outlines of global warming, the fuel efficiency improvement ratio is
anticipated to be 10.1%.
1(4) Indication items①The items to be indicated are as below.
a. Car name and typeb. Engine type and displacementc. Vehicle curb weightd. Transmission type and number of speeds
e. Fuel supply equipment typef. Main measures to improve main fuel efficiency
g. Energy consumption efficiency (use unit km/l and indicate to one decimal point)h. Manufacturer name or abbreviation②Compliance items(a) The items for indication specified in ① are to be noted in catalogs concerning applicable
LPG passenger cars. In this case, items carrying g. will be indicated in such a manner as tostand out such as by underlining, using a large typeface or changing the color of thecharacters.
(b) For LPG passenger cars presented for exhibition, the items for indication specified in ①
shall be displayed clearly in an easy-to-see place.

3. Comments, etc. concerning energy saving(1) Initiatives Government① Efforts shall be undertaken by government support and spreading awareness, for example, topromote initiatives to increase the understanding of users and improve fuel efficiency
improvements of manufacturers, etc. for the purpose of spreading LPG passenger cars,
which have excellent fuel efficiency.
② Concerning putting judging standards into practice, considerations shall be made for energy
saving efforts and emissions regulations measures of manufacturers, etc. and othercircumstances as well to promote activities consistently so that their activities can lead toachieving the target standard values.
(2) Initiatives of manufacturers, etc.
① Technological developments to improve the fuel efficiency of LPG passenger cars shall bepromoted and passenger cars with excellent fuel efficiency will be developed.
② To aim for the spread of LPG passenger cars that have excellent fuel efficiency, efforts will
be made in providing appropriate information that is helpful to users so that they can selecta LPG passenger car with excellent fuel efficiency; this includes evaluating the introductionof “energy saving labels”.
2(3) User initiatives
Efforts will be made on selecting LPG passenger cars with excellent fuel efficiency, and on
aiming for greater energy savings through appropriate and efficient use of LPG passenger cars
themselves.

4. Details, etc. of evaluations(1) Details of convening subcommittee/evaluation group (see Attachment 6)(2) List of members (see Attachment 7)3

Attachment 1

Thinking behind Necessary Scope

Passenger cars that have received type designation based on the Road Transport and Motor
Vehicle Law
Currently, gasoline and diesel cars that are the target of fuel efficiency standards based on the
Law concerning the Rational Use of Energy (hereinafter the Energy Saving Law) are passenger
cars and freight vehicles with a curb weight of 2.5 tons or less that have received typedesignation based on Article 75.1 of the Road Transport and Motor Vehicle Law. Therefore, thetarget scope of LPG cars as well is those that have received type designation under the Road
Transport and Motor Vehicle Law.
However, for LPG cars, at the current time there are no freight vehicles that have received
type designation, so at this time only passenger cars are the target. As for freight vehicles though,evaluations will be made when they receive type designation in the future. (Incidentally, thegross units shipped in FY2001 of LPG cars (passenger cars and freight vehicles) was about
38,000 units, of which about 34,000 units had type designation, approximately 90% of theoverall total.)
Furthermore, concerning modified cars, careful evaluations will be made in the future on theirhandling including clarifying responsibility and other issues in the Energy Saving Law
concerning the party making the modifications.

4Attachment 2

Thinking behind the Target Year

The target year for the achievement of target standard values shall be FY2010.

From the viewpoint of global warming countermeasures, it is essential that LPG cars whichhave achieved the target standard values be fully disseminated by the first commitment period(from 2008 to 2012) in the Kyoto Protocol, and it is desirable that the target standards beachieved as a short a time span as possible.
On the other hand, in the same way as with gasoline passenger cars, major improvements tothe fuel efficiency of LPG cars and launching new models (with new engines, adopting new
body structures, etc) are normal, and the new model cycle for LPG cars tends to be longer thanregular passenger cars given that LPG cars are used mostly as taxis. Therefore, so that there is atleast one opportunity for new models until the target year, it is necessary to consider setting it
longer than the four to five years of the new model cycle for regular passenger cars.
Given the above, the target year for achievement of target standard values for LPG cars is set
for FY2010.

5

Attachment 3

Thinking behind the Energy Consumption Efficiency (Fuel Efficiency) Measurement
MethodThe 10-15 Japanese test mode shall be the measurement method.

The 10-15 Japanese test mode specified in the Road Transport and Motor Vehicle Safety
Standards (1951 Ministry of Transport Law 67) Article 31.2, reflects metropolitan driving
conditions such as traffic and metropolitan highway facilities based on driving performancestudies in major metropolitan areas in Japan. This mode is currently being adopted to measureemissions of LPG cars.
The Japanese 10-15 mode is also currently used in measuring the energy consumption
efficiency (fuel efficiency) of gasoline and diesel cars that are the target of the Energy Savings
Law.
Given the above, the Japanese 10-15 mode has been adopted for energy consumption
efficiency of LPG cars. Furthermore, the energy consumption efficiency (fuel efficiency) of
LPG cars is a value indicated in kilometers of driving distance per one liter of fuel when driven
in the 10-15 test mode, and the value (inspection value) measured by the Minister of the
Ministry of Land, Infrastructure and Transport per car with type designation is appropriate.

6Outline Schematic of the Japanese 10-15 Mode Cycle Based on Specifications ofArticle 31 of the Road Transport and Motor Vehicle Safety Standards(seconds)

1st Cycle

2nd Cycle

3rd Cycle

Acceleration Pattern

No. inDiagram

Acceleration

Time (seconds)

No. inDiagram

Acceleration

Time (seconds)

1
2

IdlingAcceleration
0→20 ㎞/h
Fixed acceleration
20 ㎞/hDeceleration
20→0 ㎞/h
Idling

20
7

1
2

65
18

15

3

7

4

16

5

Acceleration
0→40 ㎞/h
Fixed acceleration
40 ㎞/hDeceleration
40→20
Fixed acceleration
20 ㎞/hAcceleration
20→40
Deceleration
40→20
Deceleration
20→0 ㎞/h[City Area Pattern]

14

6

15

7

10

8

2

9

IdlingAcceleration
0→50 ㎞/h
Fixed acceleration
50 ㎞/hDeceleration
50→40 ㎞/h
Fixed acceleration
40 ㎞/hAcceleration
40→60 ㎞/h
Fixed acceleration
60 ㎞/hAcceleration
60→70 ㎞/h
Fixed acceleration
70 ㎞/h10

Deceleration
70→50 ㎞/h

1011

Fixed acceleration
50 ㎞/hAcceleration
50→70 ㎞/h
Fixed acceleration
70 ㎞/hDeceleration
70→30 ㎞/h
Deceleration
30→0 ㎞/h
Idling[Acceleration Pattern]

4

3
4
5
6
7
8
9

10

12
4
4
16
10
11
10

12
10
7

12
13
14

15

7

22
5
20
10
10

Note: Japanese 10-15 Mode Test: Reflects driving conditions on Japanese roads and the car isdriven along the mode on a chassis dynamometer, which measures emissions. Four cycles aremeasured with one cycle in the 15 mode added to the 10 mode.

8

Attachment 4

Thinking behind Classification for the Purpose of Setting Target Standards

Classification will be set according to emissions and common equivalent inertia weight.

(1) Emissions and vehicle curb weight are interrelated, so it is appropriate that the index forclassification settings of target standard values is vehicle curb weight.
(2) For emission measurements, implemented in type designation inspections based on the Road
Transport and Motor Vehicle Law Article 75, a car is driven on a chassis dynamometer using
equivalent inertia weight, and measured by having it drive on top. By using it for emissions
measurements and common classifications, evaluations of emissions and fuel efficiency canbe done at the same time to engage in effective environmental measures. Combined with this,by measuring emissions and fuel efficiency at the same time, it is also possible to aim at
easing the burden of manufacturers, etc.
(3) Classifications are set by emissions measurements and common equivalent inertia weight forgasoline and diesel cars that are already the target of energy consumption efficiency (fuelefficiency) standards based on the Energy Savings Law.
Given the above, classifications for the purpose of setting target standard values for LPG cars
will be classified by emissions measurements and common equivalent inertial weight.

9

Relationships between Vehicle Curb Weight, Test Vehicle Curb Weight and Equivalent Curb
WeightVehicle Curb Weight (kg)Test Vehicle Curb Weight(kg)

Equivalent Inertia WeightStandard Values (kg)- 452
453- 577
578- 702
703- 827
828- 1,015
1,016-1,265
1,266-1,515
1,516-1,765
1,766-2,015
2,016-2,265
2,266-2,515
2,516-2,765
2,766-3,140
less than 500kg skipped- 562
563- 687
688- 812
813- 937
938-1,125
1,126-1,375
1,376-1,625
1,626-1,875
1,876-2,125
2,126-2,375
2,376-2,625
2,626-2,875
2,876-3,250
less than 500kg skipped

500
625
750
875
1,000
1,250
1,500
1,750
2,000
2,250
2,500
2,750
3,000
less than 500kg skipped

Test Vehicle Curb Weight＝Vehicle Curb Weight (kg)＋110 (kg)10

(Reference) Equivalent Inertia Weight
When measuring emissions in the test facility, a chassis dynamometer is used to recreate
actual road conditions, but to recreate the inertia of the car’s curb weight, a flywheel is used.
The flywheel used is set to the various kinds of curb weights depending on the range of the curb
weight of the vehicle being tested. The set flywheel weight is called the equivalent inertia
weight.
Use is based on regulations in Attachment 24 gasoline car 10-15 Japanese test mode emissions
measurement technology standards in the “Concerning Enactment of Technology Standards aspart of the partial revision of the Road Transport and Vehicle Safety Standards” (former
Ministry of Transport Automobile Agency (Automobiles No. 899.2, Oct. 1, 1983)

Vehicle cooling equipment

Throttle monitor
Emissions collection Emissions analyzer
equipment(CVS)

Data recorder
Drum
Torque measure
Acceleration device
Accelerator equipment

Vehicle pattern weight equipment(vehicle weight inertia flywheel)

11

Schematic of Small Chassis Dynamometer

Attachment 5

Thinking behind Setting Target Standard Values(1) For the target standard values of LPG passenger cars in the 1,266-1,515kg (equivalent
inertia weight of 1,500kg) class of type designated cars, the focus is on currently
commercially available passenger cars with the best fuel efficiency (top-runner cars), taking
into consideration such items as improvements in fuel efficiency through technology
improvements, effects on fuel efficiency by emissions regulations and fuel characteristics.
(2) When setting the target standard values, no classification is made for automatic transmission
cars (AT cars) and manual transmission cars (MT cars); the policy is to use the fuelefficiency of AT cars as the base, and considering the launch ratio in the target year of MT
cars, that is thought to be a cause for improvement in the target standard values.
(3) For non-type designated cars and other curb weight classifications, the base target standard
value classification will be the curb weight of 1,266-1,516, in consideration of that being thetarget standard value for gasoline passenger cars.
Target Standard Values for LPG passenger cars
Classification(curb weight)
Target standard
value (km/l)

-702

703
-827

828
-1015

1016
-1265

1266
-1515

1516
-1765

1766
-2015

2016
-2265

2266-

15.9

14.1

13.5

12.0

9.8

7.9

6.7

5.9

4.8

1. Concerning target standard value settings in type designated car classifications
Currently, LPG car models receiving type designation are only passenger cars with a curb
weight classification of 1,266-1,515kg (equivalent inertia weight of 1,500kg), and as the target
standard values in the applicable classifications are based on the “top-runner system” approach,it was decided upon to focus on currently commercially available passenger cars with the best
fuel efficiency, taking into consideration such items as improvements in fuel efficiency throughtechnology improvements, effects on fuel efficiency by emissions regulations and fuelcharacteristics.

(1) Primary factors in fuel efficiency improvements
12Given expectations for technologies considered when setting standards for gasoline
passenger cars and their fuel efficiency improvement ratio, a hearing was held with
manufacturers, etc. concerning characteristics and related issues of LPG passenger cars, theset fuel efficiency improvement technology and fuel efficiency improvement ratio for LPG
passenger cars was set as below. However, for these technologies, though they are notimmediately applicable to all models, they are in combination with forecasts of future
deployment ratios for target standard value settings.

13

Primary factors infuel efficiency
improvements①Engineimprovements

Deployment Reflection
Fuel
ratio (%)
in target
efficiency
standard
improvement
values (%)
ratio (%)
8.8

5.4

1.5 Given estimates of fuel efficiency

Switch to
4-valve/combust
ion chamber
improvements

1.5

Variable-valve
timing

0.5

100

0.5

Electronic
controlfuelinjectionequipment

2.0

100

2.0

Idle revolution
reduction

1.5

90

1.4

② Air-resistance
reduction

0.5

100

0.5

③Engine loss, etc.
reduction
Improve AT

Calculation approach, etc.

100

improvements when establishingtarget standard values for gasoline
cars, highest estimated values
applicable for current LPG cars
adopted.
Some technology already deployed in
LPG cars; highest values adopted onthat assumption.
Given estimates of fuel efficiency
improvement when establishingtarget standard values for gasoline
cars, highest values adopted for AT
LPG cars.
The highest values estimated incurrent LPG cars are adopted. The
deployment ratio is set given that
there is technology not compatible
with idling-stop equipment
For gasoline cars, a max. fuelefficiency improvement is possible,
however with use restrictions of LPG
cars to taxis, 0.5% is adopted.

1.0
0.5

0.5 Some technology already deployed in100

current top-runner cars, highest value
adopted on that assumption.

Switch to
high-gear④
Other
improvement
technologies
Idling-stop
equipment

1.0

0.5 Current LPG cars differential ratio

50

assumed to be one rank lower andimprovement ratio set. However,since even if applicable technology is
deployed, about half the cars will
have no fuel efficiency benefits, so
deployment ratio is set at 50%.

0.9

9.0

10

0.9 Fuel efficiency improvement ratio isan actual measurement value.
Equipment deployment ratio in LPG
cars is currently under 1%. By
FY2010, deployment is expected to
be around 10% at most.

14

⑤ Fuel efficiency
improvements bylaunching MT cars
Primary factors indegraded fuelefficiency①Measures for
new long-termemissions
regulations

10.0②Safety measures

-0.5

10

1.0

Given expected spread of MT cars
noted below in 2., the ratio is set ataround 10% at the highest by 2010.

-3.0

-2.5

１００

-2.5 Portion of technology alreadydeployed in current top-runner cars tobring down fuel efficiency, andlowest values adopted on thatassumption.

-0.5 Considering pedestrian protection

100

regulations expected in the future anddegraded fuel efficiency from off-set
front collision regulation measures,
lowest values adopted on thatassumption.

Total

5.8

15

While these have been adopted as primary factors for improving fuel efficiency whenestablishing target standard values for gasoline passenger cars, the technologies not adopted
for establishing standards of LPG passenger cars are listed below.
1) Due to the boiling point of LPG being close to normal temperature and difficulty insecurely maintaining a liquid or gaseous state given the fuel’s characteristics, it iscomplicated to create a safe composite mixture in the combustion chamber for various
conditions given the fuel characteristics. Therefore, direct injection engines are notanticipated to be applicable for LPG engines.
2) For reducing friction, independent fuel efficiency improvements upon adopting 4-valve
or variable-valve timing are not expected.
3) As for adopting the use of lightweight materials in the chassis, taking the example ofseeking durability and reliability of 500,000km for a taxi, which is several times morethan for ordinary gasoline passenger cars, achieving the same certain level of durability
and reliability at the 50,000km level with lightweight alloys and resin materials is not
anticipated, and from economy in costs as well, application to LPG passenger cars isdifficult.
4) As for adopting a chassis lightweight drive structure, securing durability and reliabilityon the 500,000km level are not anticipated and since the equipment requires even more
maintenance than normal taxis, the possibility for acceptance by users is low.
Furthermore, if one considers that current taxis have no need for front-wheel,
forward-drive setups and other reasons, application to LPG cars is difficult.
5) As for adopting low skid low resistance tires, for the long driving distances of LPG
passenger cars, an essential element on which the most focus is on is costs andsecuring durability in terms of strength and wear, but improvements in material quality
and composition that aim for low-skid low resistance to support taxi durability andreliability are difficult.
6) AT lockup region expansion (flex-lockup system used in gasoline passenger cars) isdifficult to apply to LPG passenger cars since securing durability at the 500,000km
level of the lockup clutch is not anticipated.
7) Use of a continuously variable transmission (CVT) is difficult to apply to LPG cars
since securing durability at the 500,000km level from the point of the durability of themetal belt is not anticipated.
8) As for the use of electric power steering, newly structured electric power steering thatenables applicability for cars other than light cars is not anticipated to secure durability
and reliability at the 500,000km level and is difficult to apply to LPG cars.
9) As for A/F feedback three-way catalytic converters, electronic ignition equipment, highcompression ratios and OHCs, these are technologies already being adopted in
top-runner cars among current LPG passenger cars and are not included as primaryfactors for fuel efficiency improvements in LPG passenger cars in the future.
16

(2)Primary factors in effects on fuel efficiency
1) Measures for emissions regulations
In order to respond to emissions regulations anticipated by 2005 (new long-termemissions regulations), degraded combustion arising from readapting ignition periods toreduce NOx as well as rises in exhaust back pressure due to catalyst improvements(volume increases, etc.,) are considered to have effects on worsening fuel efficiency.
2) Responses to safety regulations
Combustion is considered to degrade given weight increases due to responses topedestrian protection regulations and off-set front collision regulations expected in the
future.
Given the above, the target standard value is 9.8km/l for passenger cars with a curb weightclassification of 1,266-1,515kg (equivalent inertia weight 1,500kg)
Target Standard Values in the Curb Weight 1,266-1515kg Classification
14.0
ＭＴ cars

ＡＴ cars

13.0

Fuel efficiency (km/l)

12.0
11.0
10.0

9.3

9.8

+5.8%

9.0
8.0
7.0
6.0
1,100

1,300

1,500
Curb Weight (kg)

17

1,700

2. Handling of AT and MT cars
In the future, the ratio of MT cars among LPG passenger cars can be expected to decrease,
therefore the target standard values of LPG passenger cars have not been classified into AT and
MT cars. The energy consumption efficiency (fuel efficiency) of AT cars serves as the base andgiven consideration of the deployment ratio of MT cars in the target year, considerations weremade as improvement reasons of standard target values.
Forecast of MT Ratio of LPG passenger cars-◆- LPG passenger cars-□- Gasoline passenger cars

MT Car Ratio
Estimate from Gasoline Car Trends

Fiscal Year18

6% level3. Target standard value settings in classifications not existing in type designated cars
Among classifications not existing in currently type designated cars, the target standard values
that are set for classifications not existing in current type designated cars are appropriate for typedesignated cars considered to have a relatively high possibility of existing.
Furthermore, concerning basic composition and fuel efficiency improvement technologies, etc.
of LPG passenger cars, the fuel used is different, but since it is generally similar to that used ingasoline passenger cars, the target standard values of curb weight classifications of LPG
passenger cars in which type designated cars do not currently exist, and the calculations fromtarget standard values of gasoline passenger cars of the same curb weight classification areappropriate. As the following equation specifically shows, the target standard value
classification of the curb weight 1266-1515kg of which type designated LPG passenger cars
exist is calculated from the ratio of standard target value of gasoline passenger cars in the same
curb weight classification (curb weight 1266-1515kg) with the calorific values in LPG.

9.8 (Target standard value of LPG passenger cars with curb weight of 1266-1515kg)
Each classification’s
target standard value=Ax
10.2 (target standard value of gasoline passenger cars with curb weight of 1266-1515kg
converted to calorific value of LPG)

However, A: target standard value of gasoline passenger cars in each classification is value converted to calorific value of
LPG.

The results below are the settings of target standard values for LPG passenger cars.
LPG Passenger Cars Target Standard Values
Classification

-702

703

(Curb weight kg)

828

1016

1266

1516

1766

2016

-827

-1015

-1265

-1515

-1765

-2015

-2265

2266-

Target standard value (km/l)

15.9

14.1

13.5

12.0

9.8

7.9

6.7

5.9

4.8

Emission of CO2 per 1 km
driving (g-CO2/km)

104

118

123

138

169

210

247

281

345

2016

2266-

(Reference) Gasoline Passenger Cars Target Standard Values
Classification-702(curb weight kg)
Target standard value (km/l)

LPG calorific value conversion (km/l)
CO2 equivalent conversion (km/l)

703

828
-827

21.2
16.6
15.1
109

18.8
14.7
13.4
123

1016

1266

1516

1766

-1015

-1265

-1515

-1765

-2015

-2265

17.9
14.0
12.8
130

16.0
12.5
11.4
145

13.0
10.2
9.3
179

10.5
8.2
7.5
221

8.9
7.0
6.4
261

7.8
6.1
5.6
298

Emission of CO2 per 1 km
driving (g-CO2/km)
1. LPG calorific value conversion=0.782 x Gasoline passenger car target standard value
2. CO2 equivalent conversion=0.714 x Gasoline passenger car target standard value

19

6.4
5.0
4.6
363

LPG Passenger Car Target Standard Value and Gasoline Passenger Car Standard Conversion
Values10-15 Japanese Test Mode Consumption (km/L)

LPG passenger cars target standard value
Gasoline passenger cars target standard value (LPG conversion value)
Gasoline passenger cars target standard value (CO2 Equivalent conversion)

Curb Weight (kg)20

(Reference 1)
Trial Calculations concerning Improvements in Energy Consumption Efficiency (FuelEfficiency)

Combined with the introduction of LPG passenger car target standard values, the energy
consumption ratio (fuel efficiency) improvement ratio calculated from actual values in FY2001
and estimated values of 2010 is as below.
FY2001 Actual Results
Values

FY2010 Estimated
Values

Improvement Ratio

8.8km/l

9.8km/l

11.4%

However, as a prerequisite, the number of units and composition shipped in FY2010 is set as thesame as FY2001. When actual performance values (8.9km/l) in FY1995, the standard fiscal year
used for comparison concerning improvements in fuel efficiency standards for cars in broad
outlines of global warming, are compared using the same method as FY2010 estimated values, thefuel efficiency improvement ratio is calculated to be 10.1%.

21

(Reference 2)
Technology Trends of LPG Cars and Current Trends in Energy Saving Technology andPredictions for the Future
1. Technology Trends
LPG cars were introduced in a form that historically improved on gasoline cars. Initially,among taxis to which LPG cars were introduced, LPG from the fuel cylinder was vaporized via
a vaporizer, but a system was later adopted that supplied fuel to the engine via a mixer attached
as a substitute to the vaporizer. After that, combined with the strengthening of emissions
regulations, fine control of fuel supply by electronic control in order to adopt three-way catalytic
converters was sought, and a switch was made to a mixer system with feedback control.
In the future, for the purpose of extremely fine control of the air-fuel ratio to respond to evenstronger emissions regulations and to improve filling efficiency and fuel efficiency, trends areheading toward development and deployment of electronic control fuel injection equipment(multi-point injection; MPI). Because cars are outside the target of regulations since the High
Pressure Gas Safety Law was revised in 1999, it is expected that rather than vaporizing injection
systems, systems that inject pressurized liquid will become mainstream. In this way, the samekind of MPI systems already widely adopted in gasoline cars can be used, and they are expected
to contribute to even greater fuel efficiency and reductions in emissions.

2. Current State of Energy Saving Technology and Future Prospects
As responsive measures to improving energy usage or efficiency to improve fuel, efficiency
the following are given:• Improves energy efficiency• Reduced driving resistance (reduced air resistance, etc.)• Reduced drive loss (improved transmission efficiency, etc.)• Promotion of lightweight chassis
However, regarding structure and equipment of LPG cars, it is expected that in the future aswell aims will be made for stronger safety standards to prevent accidents and reduce injuries
when accidents happen. For the prevention of air pollution and reduction of roadside noise,stronger pollution prevention regulations concerning car emissions and noise are expected to be
successively adopted. The technologies that will respond to these measures together withincreases in the curb weight and energy consumption, etc, it is difficult to balance engine
combustion technology related directly to improving fuel efficiency.
Therefore, concerning LPG car fuel efficiency measures and improvements, it is necessary toconsider enabling the appropriate adoption of necessary technology for securing car safety andpreventing pollution, etc.
22

(1) Primary factors for improvements in fuel efficiency through engine improvements
The primary factors for fuel efficiency in the engine are as follows.
1) Reduction of pump loss
When the fuel-air mixture is pumped in the intake stroke to the engine, a heavy load ofwork is done (pump loss). Valid methods to reduce this pump loss include optimizationof the intake/exhaust valve opening and closing times of the variable valve timing
mechanism.
2) Improvement of thermal efficiency
Improvements of the engine’s thermal efficiency through higher compression ratios,
improvements in combustion and so on. Changing to four valves, improving combustion
chamber types and the like are being adopted to improve combustion.
(2) Main technologies to improve fuel efficiency
1) Valve control system(a)Changing to four valves/combustion chamber improvements
Changing to four valves increase the intake values to two and exhaust valves to two. By
expanding the path for the fuel-air mixture and emissions, the volumetric efficiency is
increased and pumping loss decreased. Along with these improvements, the central
position of the ignition in the combustion chamber leads to combustion improvements.
At the same time, by improving the shape of the combustion chamber and so on,
combustion is sped up, thermal efficiency increased, and knocking controlled, securing
optimal ignition periods.
(b)Variable valve timing
A system that controls the most suitable opening and closing timing depending on
various driving conditions by varying the opening and closing timing of the intake andexhaust valves. While the high-speed revolution region receives high output, thelow/mid revolution raises the torque in combination with the gear ratio, increasing fuelefficiency. The EGR (exhaust gas recirculation) volume is increased, pumping loss
reduced and fuel efficiency increased.

23

Low-speed cam

Spark plug

High-speed cam

High-speed follower
Intake valves
Low-speed follower

Exhaust valvesRocker shaft
Valve●Four valve combustion chamber2) Electronic control fuel injection equipment (ＭＰＩ)
System that injects fuel in liquid and gaseous states to each valve, enabling precise fuelcontrol. Improvements in fuel efficiency can be aimed for by output improvements
through increasing filling efficiency, expansion of fuel-cut region when decelerating, andimprovements in distribution properties of fuel among the valves.

Control Valve

Fuel tankPressure regulator

Fuel pump

Surge tankControl Valve
Ignition coil

Liquid injector

LPG Electronic Fuel Injection System (liquid injection)243) Reducing idling revolutions
Technology exists to reduce the fuel consumption amount by reducing the number of
revolutions during idling, and it is necessary to have combustion improvements, precise
fuel control and vibration measures and so on in order to secure safe revolutions.
4) Reducing air resistance
Air resistance can be reduced by making improvements to the body shape.
5) AT Improvements (including electronic technologies)
Regarding AT, improving the efficiency of the torque converter (transmission equipmentthat uses fluids to convert torque), best shift control through using electronic control andexpansion of the lockup region increases fuel efficiency.
6) Switching to high-gear
In aiming to improve engine output, fuel efficiency can be improved by reducing engine
friction through lowering the gear ratio of the differential and reducing the number
engine revolutions used. However, there are also models that have optimal points in therelationship with the engine’s optimal fuel efficiency region and driving performance,and have no fuel efficiency improvement effects7) Idling Stop Equipment
System to stop engine idling automatically when vehicle is stopped and restart it
automatically when it starts moving. With it actual driving fuel efficiency improvements
can be aimed for.
(3) Primary factors requiring attention when establishing target standard values
1) Measures for emissions regulations
Effects on fuel efficiency are inevitable from combustion degrading from readapting
ignition times to reduce NOx and catalyst improvements (increase in volume, etc.) inorder to respond to emission regulations (new-long term emissions regulations) expectedby 2005. Furthermore, in the case of being used as taxis, since they drive long distances
above endurance distances (80,000km), it is necessary to fully consider catalyst
reliability and durability in response to these measures.
2) Responses to safety regulations
Curb weight increases to respond to pedestrian protection regulations and offset frontal
collision regulations will result in effects on fuel efficiency.
(4) Technology adopted for the reason of improving fuel efficiency when establishing target
standard values for gasoline passenger cars that cannot be anticipated to be a primary factor
in improvements in fuel efficiency in LPG passenger cars

251) Direct injection engine
Engine that directly injects fuel into the cylinders. Uses an even leaner fuel-air mixture
by stratifying the mixture and combusting it to improve fuel efficiency performance. It
uses an extremely rarefied region with a mixture up to 40-50:1.
2) Reducing friction
Technology that reduces sliding portions in friction loss such as pistons, cranks, valves,etc, in aiming to improve fuel efficiency. While methods can be considered to reduce
piston ring tension and sliding areas, it has effects on durability and other area.
Meanwhile, if four valves or variable-valve timing technology and the like are adopted,
since it increases friction, this is not anticipated as having fuel efficiency effects alone.
3) Adoption of lightweight materials in body
Fuel efficiency is improved by adopting lightweight materials such as lightweight alloys,
resin materials and so on, lightening the overall vehicle weight.
4) Adoption of chassis lightweight drive structure
Using a front engine, front drive (FF) structure eliminates the need for a propeller shaft
throughout the body, leading to improved fuel efficiency.
5) Adoption of low rolling resistance tires
Reducing the tires’ rolling resistance coefficient through improved materials andcomposition reduces driving resistance and aims to increase fuel efficiency.
6) Expansion of AT Lockup Region
Expands the flex lockup region by having the lockup clutch affected by a minute slip
(flex lockup) by precise control in the transmission equipped with a lockup clutch fordirect connection as necessary with torque converter the purpose of avoiding slipping
loss and input/output axle, and aims to increase fuel efficiency.
7) Adoption of Continuously Variable Transmission(CVT)
Automatic transmission that enables the active use of the best fuel regions in the engine
without stages together with reducing slip loss by the belt drive. The optimum gear ratio
is set according to driving conditions, and improvements in the fuel efficiency ratio can
aimed for.
8) Adoption of Electric Power Steering
Originally, engine movement was always controlled with oil pumps, but with the use ofelectronics, control is possible so that energy is used only as necessary, improving fuelefficiency.
9) A/F Feedback Three-way Catalytic Converter
A system to detect the oxygen density level in the valve using an O2 sensor and control
the fuel volume and precisely control the theoretical air-fuel ratio with that feedback.
10) Electronic Ignition Equipment
Setting that enables optimum ignition timing according to driving conditions, improving
fuel efficiency. Even among electronic ignition equipment, knock control systems detect
26

the occurrence of knocking and control ignition timing, enabling driving with higher
compression ratios and optimum ignition timing.
11) High Compression Ratio
The theoretical thermal efficiency ratio is improved by raising the compression ratio.
Meanwhile, since it prevents abnormal combustion such as knocking, it is necessary tohave combustion chamber improvements and use high-octane fuel.
12) Switch to OHC
Structure that positions the cam shaft over the cylinder heads, opening and closing thevalves. Compared to the original OHV system with the original camshaft position on thecylinder block, it is possible to aim for high revolutions and high output, therefore
improving fuel efficiency by low exhaust volumes in the same output.

27

Attachment 6

General Resources Energy Investigation Committee, Energy Savings Standards Section,
Automobile Standards Judging Subcommittee
LPG Car Fuel Efficiency Standards Evaluation Group Interim Report
Session Details

1st Subcommittee/Evaluation Meeting (September 10, 2002)
・Setup of subcommittee
・Basic approaches concerning establishment of judgment standards and revisions
・Current status of LPG cars
・Target scope
2nd Subcommittee/Evaluation Group (November 12, 2002)
・Target scope
・Energy consumption efficiency and its measurement methods
・Classifications for target standard value settings
・Target standard values and target fiscal year
3rd Subcommittee/Evaluation Group (December 11, 2002)
・Target standard values
・Disclosure・ Interim Report
Invitation for public comment on the interim report (December 25, 2002).
4th Subcommittee/Evaluation Group (February 18, 2003)
・Final Report28

Attachment 7

General Resources Energy Investigation Committee, Energy Savings Standards Section,
Automobile Standards Judging Subcommittee
LPG Car Fuel Efficiency Standards Evaluation Group
List of Committee Members

Committee Chairman
Makoto Ikegami
Professor, Dept. of Engineering, Fukui University of Technology
Committee Members
Norimasa Ohtera
Managing Director, The Energy Conservation Center, Japan
Matsuo Odaka

Environment Energy Section Chief, National Traffic Safety andEnvironment Laboratory (an Independent Administrative
Institution)

Takeyuki Kamemoto Professor, Department of Engineering, Tokai University
Hirofumi Kitamura

Committee Chairman, Vehicle Materials Committee, National Passenger
Automobiles Association

Kazutaka Obata

Vice Chairman, Japan Auto-Body Industries Association Inc.

Keizo Saito

Collaboration Coordinator, Collaboration Department, National Instituteof Advanced Industrial Science and Technology (an Independent
Administrative Institution)

Narimasa Suzuki

Director, Japan Trucking Association

Takao Suzuki

Vice Chairman and Managing
Manufacturers Association, Inc.

Yasuhiro Daisho

Professor, Science and Engineering, Waseda University

Yasuhiro Fukuma

Director, Japan Automobile Research Institute

Director,Japan

Automobile

Masatoshi Matsunami Executive Director, Japan Automobile Federation
Shun Wakiyama

Executive Director, Japan Automobile Importers Association

29