Future Policy forMotor Vehicle Emission Reduction(Fourteenth Report)

August 20, 2020

Central Environment Council

In case of any doubts, please refer to the original text written in Japanese.

Future Policy forMotor Vehicle Emission Reduction(Fourteenth Report)

August 20, 2020

Central Environment Council

Chukanshin No. 1131
August 20, 2020

To:

His Excellency Shinjiro Koizumi
Minister of the Environment

From： Kazuhiko Takeuchi
Chairperson
Central Environment Council

Future Policy for Motor Vehicle Emission Reduction (Fourteenth Report)

In response to Inquiry No. 31 of May 21, 1996, on “Future Policy for Motor Vehicle
Emission Reduction,” the Central Environment Council has successively made reports
starting from the interim report (Chukanshin No. 83 of October 18, 1996) to theThirteenth Report (Chukanshin No. 972 of May 31, 2017).
Among the above reports, the Thirteenth Report cited, regarding the regulations onparticulate matter (hereinafter referred to as “PM”), that since there was a certain
correlation between PM mass and PM particle number, it was possible to reduce PMemissions by introducing regulations to measure particle number in addition to theconventional regulations to measure particle mass, and thus that the council would
discuss the introduction of regulations on PM particle number (hereinafter referred toas “PN”) for diesel vehicles and vehicles equipped with in-cylinder direct injection
gasoline engines (hereinafter referred to as “gasoline direct injection vehicles”).
In addition, regarding special motor vehicles fueled by gasoline or liquefied
petroleum gas (LPG) (hereinafter referred to as “gasoline/LPG special motor vehicles”),
the report also considered the introduction of a transient cycle to properly evaluate
measures to reduce emissions in accordance with the actual use of such vehicles, thestrengthening of regulations on emissions in consideration of trends in thecorresponding technological developments, and measures to reduce blow-by gas.
Moreover, to promote further international harmonization of emission test methods,
it was necessary to study test cycles for low-powered passenger cars, etc.
For this purpose, the Expert Committee on Motor Vehicle Emissions under the Air,
Noise, and Vibration Committee has discussed these issues. The results of thediscussion were compiled in the Fourteen Report by the Expert Committee on Motor1

Vehicle Emissions, as attached.
The Air, Noise, and Vibration Committee discussed this Fourteenth Report andconcluded that it was appropriate to adopt the Fourteenth Report and continue its
contribution to the protection of the air quality in Japan through prompt harmonizationof motor vehicle emission test methods to reduce motor vehicle emissions.
The Council thus makes the following report:
Details
1. Measures for Fine Particulate Matter, etc.
As the conventional measurement method under the PM regulations is based on themeasurement of the mass of the particles trapped in the filter, the regulation values
cannot be reduced significantly due to inadequate measurement accuracy. On theother hand, the PN measurement method, which removes the volatile components ofPM and counts the number of particles, enables more accurate measurement.
According to the results of research conducted by the Ministry of the Environment,
there is a certain degree of correlation between PM mass and PN. Therefore, it isappropriate to introduce PN regulations for diesel vehicles and vehicles equipped within-cylinder direct injection gasoline engines, as the introduction of PN regulations canvirtually reduce PM emissions.
For emission test methods including emission test cycles to introduce the PN
regulations, it is appropriate to apply WHDC (Worldwide harmonized Heavy DutyCertification) including WHTC (Worldwide Harmonized Transient Cycle) and WHSC
(Worldwide Harmonized Steady state Cycle), which were developed by the UnitedNations, to heavy-duty vehicles (excluding gasoline vehicles), WLTP （ Worldwide
harmonized Light vehicles Test Procedure) including WLTC (Worldwide Light-duty TestCycle) to passenger cars, etc. and JE05 mode to gasoline heavy-duty vehicles.
It is appropriate to make the allowable maximum desired values as strict as feasible,
based on the degree of the achievement of the environmental standards for PM2.5 andtechnological developments trends at home and abroad, as shown in Attached Tables
1 and 2.
With regard to the application start time, it is appropriate to commence theapplication by the end of 2024 for gasoline vehicles and by the end of 2023 for dieselvehicles, in consideration of the period of time required for automobile manufacturers
to develop technologies, etc.
2. Measures to Reduce Emissions from Special Motor Vehicles
Regarding gasoline/LPG special motor vehicles, the regulations are implemented for
those with an engine rated output of 19 kW or more but less than 560 kW, and C2
2

mode (7-mode), which is a steady-state mode, is adopted for these vehicles. However,as the steady-state cycle alone cannot take into consideration time delay in catalyst
temperature caused by transient use and the deterioration of the performance of thethree-way catalyst due to unsteady nature of emissions flowing into the catalyst, it may
not properly evaluate emission reduction measures commensurate with the actual useof the vehicles.
In addition, regulations to ban the release of blow-by gas into the atmosphere are
not currently introduced for gasoline/LPG special motor vehicles.
Consequently, it is appropriate to set the allowable maximum desired values forgasoline/LPG special motor vehicles for the next term as follows:
2.1. Test cycles, etc. for special motor vehicles and allowable maximum desired values
In light of the comparison between emissions measured in the transient test cycles
adopted in the U.S. and Europe (hereinafter referred to as “LSI-NRTC”) and thosemeasured in the test cycles based on the actual use of vehicles in Japan (JTC), air
quality is expected be improved and worldwide harmonization of emission test cycles
will be promoted when LSI-NRTC is used as an emission test cycle in Japan. Therefore,
it is appropriate to introduce LSI-NRTC, shown in Attached Figure 1, as a transient
cycle of the test method in the emission regulation for special motor vehicles in thenext term.
As some engines generated more emissions when tested in steady-state cycles thanin LSI-NRTC, it is appropriate to continue to use C2 mode (7-mode). In addition, it isalso appropriate, from the perspective of international harmonization of technicalstandards, to introduce 7M-RMC as shown in Attached Figure 1 to allow the selectionof either the C2 mode (7-mode) or 7M-RMC, as the amount of emissions in 7M-RMC,
which can be selected instead of C2 mode (7-mode) in the U.S., is the same as that inC2 mode (7-mode).
The allowable maximum desired values when introducing LSI-NRTC and 7M-RMC
are shown in Attached Table 3, and it is appropriate to adopt them by the end of 2024.
2.2. Measures to reduce blow-by gas
A survey of the technologies introduced in recent gasoline special motor vehicles
showed that it was technologically possible to prohibit the release of blow-by gas into
the atmosphere. Therefore, it is appropriate to prohibit the release into the atmosphereof blow-by gas emitted from gasoline/LPG special motor vehicles with a rated outputof 19 kW or more but less than 560 kW.
With regard to the application start time, it is appropriate to adopt the prohibition by
the end of 2024, in conjunction with the application of the allowable maximum desired
values for emissions.
33. International Harmonization of Emission Test Methods for Passenger Cars, etc.
Vehicles to which WLTC is applied are divided into three categories based on thevalue of the maximum power output of a vehicle divided by the vehicle mass in an
unladen state (running order) (Power to Mass Ratio, hereinafter referred to as “PMR”).
They are classified as Class 1, Class 2 and Class 3 in ascending order of PMR, with22 W/kg and 34 W/kg as the borderlines.
In developing the test cycles for Class 1 and Class 2 vehicles, there is no actualvehicle driving data as there are no Class 1 or Class 2 vehicles in Japan. Japan has
not introduced the relevant test cycles until now, as the actual vehicle driving data inother countries where most vehicles are low-powered and travel at low speed is taken
into account. However, the United Nations is considering the development of the UNRegulation on WLTP as a new international standard, and when this UN Regulation isadopted by Japan and is subject to mutual recognition, it is necessary to also introduce
the test cycles.
Class 1 and Class 2 vehicles are not sold in Japan and have a very limited impact
on the environment. On the other hand, the adoption of the UN Regulation will reducethe burden on automobile manufacturers and allow them to implement more efficientenvironmental measures. Therefore, the test cycles applied to WLTC Class 1 andClass 2 vehicles as specified in Attached Figure 2 should be introduced in Japan, andthe test cycles by vehicle type as in the UN Regulation should be applied as well. Thetest cycle applied to Class 1 vehicles includes the low-speed phase, medium-speedphase, and additional low-speed phase, and the test cycle applied to Class 2 vehicles
includes the low-speed phase, medium-speed phase, and high-speed phase, as withthe test cycle applied to Class 3 vehicles.
With regard to the application start time, it is appropriate to adopt the test cycles byvehicle type as in the UN Regulation in conjunction with the adoption of the UN
Regulation on WLTP.
4. Issues to be Considered in the Future, etc.
The Expert Committee on Motor Vehicle Emissions will continue studying issues tobe considered in the future as listed in the Fourteenth Report. Among others, theCommittee will place special importance on discussing the issues below. Furthermore,
the Japanese Government should promote the measures proposed in the report,
including those related to the comprehensive policy for motor vehicle emission
reduction.
4.1 Measures for fine particulate matter, etc.
Currently, discussions are being held in the United Nations on whether to reduce thelower limit of detection range of the PN measurement method from the current value4

of 23 nm to 10 nm in particulate diameter. In addition, the revision of the test method
is being discussed based on the results of round-robin tests to improve the accuracyof the measurement method including a diameter of 23 nm. Japan should continue toparticipate in and contribute to the activities of the United Nations by sharing its
knowledge on the actual status of emissions in Japan, etc. with the United Nations,and discuss revisions to the test method, etc. considering Japan's environment andimpact of vehicle emissions
4.2 Measures for brake dust and tire dust
In addition to the emissions from exhaust pipes, PM emissions from motor vehicles
also include fine particles caused by the wear of brakes and tires, and the relative
ratios of brake dust and tire dust to the overall PM emissions are on the rise. In
particular, test methods for brake dust are studied in detail at various research institutes.
The United Nations has agreed to develop test methods for that by 2021. As roundrobin tests using the test methods are scheduled to be conducted in the future, Japan
should also actively participate in and contribute to the development of international
standards by cooperating in the round-robin tests and sharing the findings gained
through surveys, etc. in Japan with the United Nations.
4.3 Measures to reduce emissions from special motor vehicles
For special motor vehicles with a rated output of 19 kW or more but less than 560
kW, it is necessary to consider strengthening the emission regulation for them asnecessary, taking into account the state of air pollution, contribution of their emissions,
technological developments trends, and international trends.
Particularly with regard to measures to reduce fine particulate matter, it is necessary
to consider the required measures, including the PN regulations introduced for vehicles
other than special motor vehicles, as the contribution of special motor vehicles to PMemissions is expected to increase.
End5

Attached Figure 1

Normalized engine speed (%)
Normalized torque (%)

Exhaust pipe emission test cycle for gasoline/LPG specialmotor vehicles
Engine speedTorqueTime (s)LSI-NRTC（Large Spark Ignition engines Non-Road Transient Cycle）
TorqueEngine speed

Engine speed

TorqueIntermediateIdle

Time (s)7M- RMC（7M Ramped-Modal Cycle）

6Engine speed

Normalized torque (%)

Rated

Attached Figure 2

Exhaust pipe emission test cycle for passenger cars, etc.
● Test cycle (i)120Vehicle
speed
車速, km/h(km/h)

Low-speed phase

Medium-speed phaseLow-speed phase

600

1200

10080
60
40
200
0200

400

800
1000
時間 (s),s
Time

1400

1600

1800

1600

1800

1600

1800

● Test cycle (ii)
Vehicle車速speed, km/h (km/h)

120

Low-speed phase

Medium-speed phase High-speed phase

1008060402000200

400600800
1000
時間 (s),s
Time

1200

1400

● Test cycle (iii)
Vehicle車速speed, km/h (km/h)

120

Low-speed phase

Medium-speed phase High-speed phase

10080
60
40
2000200

400600800
1000
時間 (s)
,s
Time

71200

1400

● Test cycle (iv)
Vehicle車速speed, km/h (km/h)

120

Low-speed phase

Medium-speed phase High-speed phase

100806040
2000200

400600800
1000
時間 (s)
,s
Time

1200

1400

*Note: The test cycle is determined for each type of vehicle as follows:
Vehicle type

1600

1800

Test cycle

Gasoline/LPG passengercars

Vehicles with a PMR not exceeding 22 W/kg

Test cycle (i)Gasoline/LPG lightfreight vehicles

Vehicles with a PMR exceeding 22 W/kg but

Gasoline/LPG light-

not exceeding 34 W/kg

weight vehicles

Vehicles with a maximum

Gasoline/LPG mediumweight vehicles
Diesel passenger cars

Test cycle (ii)speed of less than 120
Vehicles with a

Test cycle (iii)

km/h

PMR

Diesel light-weightexceeding

Vehicles with a maximumvehicles

34 W/kg

speed of 120 km/h orDiesel medium-weight

Test cycle (iv)morevehicles
Test cycle (i): a test cycle applied to Class 1 vehicles in WTLP-gtr
Test cycle (ii): a test cycle applied to Class 2 vehicles in WTLP-gtr (excluding the extra-high-speed phase)
Test cycle (iii): a test cycle applied to Class 3a vehicles in WTLP-gtr (excluding the extra-high-speed phase)
Test cycle (iv): a test cycle applied to Class 3b vehicles in WTLP-gtr (excluding the extra-high-speed phase)8

Attached Table 1

Allowable Maximum Desired Values for Emissions fromGasoline Direct Injection Vehicles
Allowable maximum desired value(average)

Vehicle type (Note 1)

PN

Gasoline/LPG passenger cars (Note 2)
Gasoline/LPG light-freight vehicles(Note 3)Gasoline/LPG light-weightvehicles

6.0×1011 [particles/km](Note 4)Gasoline/LPGvehicles (Note 5)

medium-weight

Gasoline/LPG heavy-duty vehicles(Note 6)6.0×1011 [particles/kWh](Note 1) Limited to vehicles equipped with in-cylinder direct injection gasoline engines(Note 2) Gasoline- or LPG-fueled ordinary-sized, small-sized, and light motor vehicles exclusively
used for carrying passengers and having a riding capacity of 10 people or less (excluding
those with a riding capacity of 10 people and a gross vehicle weight exceeding 3.5 tons, aswell as two-wheeled vehicles).
(Note 3) Gasoline- or LPG-fueled light motor vehicles (excluding those exclusively used for carrying
passengers as well as two-wheeled vehicles)(Note 4) Gasoline- or LPG-fueled ordinary-sized and small-sized motor vehicles with a gross vehicle
weight of 1.7 tons or less (excluding those exclusively used for carrying passengers andhaving a riding capacity of 10 people or less, as well as two-wheeled vehicles)(Note 5) Gasoline- or LPG-fueled ordinary-sized and small-sized motor vehicles with a gross vehicle
weight exceeding 1.7 tons but not exceeding 3.5 tons (excluding those exclusively used forcarrying passengers and having a riding capacity of 10 people or less, as well as two-wheeledvehicles)(Note 6) Gasoline- or LPG-fueled ordinary-sized and small-sized motor vehicles with a gross vehicle
weight exceeding 3.5 tons (excluding those exclusively used for carrying passengers andhaving a riding capacity of 9 people or less, as well as two-wheeled vehicles)

9Attached Table 2

Allowable Maximum Desired Values for Emissions from DieselVehicles
Allowable maximum desired value (average)
Vehicle type
PN

Diesel passenger cars (Note 1)
Diesel light-weight vehicles (Note 2)
Diesel medium- weight vehicles (Note 3)

6.0×1011 [particles/km]

6.0×1011 [particles/kWh] (limited to WHTC)

Diesel heavy-duty vehicles (Note 4)
8.0×1011 [particles/kWh] (limited to WHSC)(Note 1) Diesel-fueled ordinary-sized and small-sized motor vehicles exclusively used for carrying
passengers and having a riding capacity of 10 people or less (excluding those with a riding
capacity of 10 people and a gross vehicle weight exceeding 3.5 tons, as well as two-wheeledvehicles)(Note 2) Diesel-fueled ordinary-sized and small-sized motor vehicles with a gross vehicle weight of 1.7 tonsor less (excluding those exclusively used for carrying passengers and having a riding capacity of
10 people or less, as well as two-wheeled vehicles)(Note 3) Diesel-fueled ordinary-sized and small-sized motor vehicles with a gross vehicle weight exceeding
1.7 tons but not exceeding 3.5 tons (excluding those exclusively used for carrying passengers andhaving a riding capacity of 10 people or less, as well as two-wheeled vehicles)(Note 4) Diesel-fueled ordinary-sized and small-sized motor vehicles with a gross vehicle weight exceeding
3.5 tons (excluding those exclusively used for carrying passengers and having a riding capacity of
10 people or less, as well as two-wheeled vehicles)

10

Attached Table 3

Allowable maximum desired values for exhaust pipe emissions
from gasoline/LPG special motor vehicles
Allowable maximum desired value (average)
Vehicle type

Gasoline/LPG special motor vehicles(Note 1)COHCNOx

15.0 g/kWh

0.6 g/kWh

0.3 g/kWh(Note 1) Limited to gasoline- or LPG-fueled special motor vehicles with a rated output of 19 kW or
more but less than 560 kW11