1 
 Annex  
 
Outline of draft regulation  for amendments of the exhaust gas emissions regulation 
for special large motor vehicles and special small motor vehicles fueled gasoline or 
liquefied  petroleum  gas (LPG)  
(Draft partial amendments of “Public Notice that Prescribes Details of Safety 
Regulations  for Road Transport Vehicles ”, etc.) 
 
１．Background  
Japan  has introduced  the exhaust gas emissions regulations  for special motor vehicle s 
with an engine which maximum power is not smaller than 19 kW and not larger than 
560kW. For special motor vehicle s with a gasoline or LPG fueled engine, the steady test 
mode, C2 mode (7 mode), has been applied as the exhaust gas testing cycle since 2007. 
On the o ther hand, for special motor vehicle s with a diesel engine, the steady test mode, 
C1 mode (8 mode) and the Non -Road Transient Cycle (NRTC) has been applied since 
2011  and then the Ramped Modal Cycle (RMC) is also applicable as an alternative method 
of the C1 mode from 2014.  
The three way catalyst  (TWC)  is a common after treatment  device  for gasoline or LPG 
fueled special motor vehicle s. To achieve  higher reducing rate , a feedback system 
according  to condensation of oxygen in the exhaust gas measured by the O 2 sensor is 
commonly applied  to keep the air -fuel ratio properly. However, t he response delay  of 
catalyst temperature  during transient use or t he performance degradation of TWC due to 
the nonsteady inflow of exhaust gas  cannot be evaluated enough the current steady test 
cycle for gasoline or LPG special motor vehicle s installed such a TWC and feedback 
system . 
The release of blow -by gas in the air is prohibited for standard motor  vehicles, compact  
vehicles,  light vehicles,  motor cycles, motorized bicycle and diesel fueled special motor 
vehicle s. In contrast, gasoline or LPG fueled special motor vehicle s are not prohibited to 
release blow -by gas currently.  As a  result of the investigation , it show s that the recent 
gasoline fueled special motor vehicle s are technically able to comply to prohibit to release 
blow-by gas.  
Based on the situation,  the Central Environment Council published a report in August 
2020 that recommends  to reduce gas emissio ns from special large motor vehicles and 
special small motor vehicles fueled gasoline or liquefied  petroleum  gas by following 
measures. i.e. i) strengthen exhaust  gas emissions limits for carbon monoxide (CO) and 
nitrogen oxides (NO x), ii) introduce the LSI-NRTC (Large Spark Ignition Non -Road 
Transient Cycle) and 7M -RMC (7 mode Ramped Modal Cycle)  as emissions test cycles  
and iii) prohibit to release blow -by gas in the air.  
 
2. Outline of Amendment  
Regulations to be amended: Public Notice that Prescribes Details of Safety Regulations  
for Road Transport Vehicles, etc.   
2 
 Scope: special large motor vehicles and special small motor vehicles with an engine which 
maximum power is not smaller than 19 kW and not lager than 560 kW fueled gasoline 
or liquefied  petrole um gas 
 
Outline:  The amendments include i)  strengthen ing exhaust  gas emissions limits,  ii) 
introduce of the LSI -NRTC and the 7M -RMC as the emissions test cycles and iii) 
enforce ment of  installation of blow -by gas recirculation  device . 
 
i) Strengthening exhaust gas emissions limits  
ii) Introduce of the LSI -NRTC and the 7M -RMC  
 The exhaust gas emissions limits for each test cycle are shown in  the following 
table.  
 
Scope  Test Cycle Limits [g/kWh]  
Average value*3 
(maximum value)*3 Note 
CO HC NOx 
Gasoline or LPG 
Special motor 
vehicle s*1 LSI-NRTC  
15.0 
(20.0)  0.60 
(0.80)  0.30 
(0.40)  This 
amendments  7M-RMC  
or 
C2 mode*2 
C2 mode  20.0 
(26.6)  0.60 
(0.80)  0.60 
(0.80)  Current  
*1 Special large motor vehicles or specia l small motor vehicles with  a gasoline or 
LPG fueled engine which maximu m power is not smaller than 19kW and  not 
larger than  560kW  
*2 The 7M -RMC or C2 mode is selectable option  on the exhaust gas testing.  
*3 The average value is applied to type approval vehicles.  
 The maximum value is applied to non -type approval vehicles.  
 
iii) Enforcement of installation of blow -by gas recirculation  device  
   A blow -by gas recirculation  device that recirculates the leaked gases from the 
combustion chamber of the engine to the crankcase is enforced to install and shall 
be that its installation is secure and exhibits no damage . 
 
3. Proposed Schedule  
Date of adoption: around  January , 2024 
Dates of application :   
 New type engines : from October , 202 4 
 All engines: applied later than new type engines, to be determined by the adoption