Environmental performances of new Japanese vehicles: increased availability of start/stop systems

Increased use of variable intake/exhaust valve systems and eco-drive assists

2011/03/18

Summary

 Below is a summary of the environmental performances of new passenger cars released by Japanese automakers in the domestic market in 2010 through January 2011 (new models and fully-remodeled cars are reflected; OEM supplies by other automakers are not accounted for).

 Nearly all new passenger cars meet the 75% reduction level from the emissions standard set for 2005. Nearly all passenger cars, other than certain versions, are also compliant with the fuel efficiency standard set for 2010. Among all new passenger cars, the hybrid vehicles and certain gasoline-fueled vehicles meet the fuel efficiency standard set for 2015.

 Among a number of technical measures taken to improve fuel efficiency, many new passenger cars have variable valve systems in both the intake and exhaust lines of their engines. Fuel efficiency and eco-drive level indicators, eco-drive modes (priority placed on fuel efficiency by suppressive control of drive power and air conditioning) and other systems designed to support low fuel consumption are made available on more models than before.

 The availability of the start/stop systems has also been increased. They are available on five new models in total (Toyota, Nissan, Mazda and Daihatsu). Increasingly available are the systems that reduce the engine restarting time to eliminate the awkward feeling often associated with start/stop systems.

Emissions and fuel efficiencies of the new passenger cars released by Japanese automakers in the domestic market in 2010 through January 2011

Model
(Month/Year
of release)
2005 emission regulations 2010 fuel efficiency standards
75% lower
level
(SU-LEV)
50% lower
level
(U-LEV)
+ 25%
better
level
+ 20%
better
level
+ 15%
better
level
Conforming~
+ 10% better
level
Toyota Vitz
(Dec. 2010)
All grades   All other
grades
  1.3L・4WD 1.5L・MT
Toyota Ractis
(Nov. 2010)
All grades   2WD   All other
grades
 
Toyota FJ Cruiser
(Nov. 2010)
  All grades        
Toyota Passo
(Feb. 2010)
All grades   1.0L・2WD   1.3L・2WD All other
grades
Lexus CT200h
(Jan. 2011)
All grades   All grades      
Honda Fit Hybrid
(Oct. 2010)
All grades All grades
Honda Freed Spike
(Jul. 2010)
All grades   2WD     All other
grades
Honda CR-Z
(Feb. 2010)
All grades   All grades      
Nissan Leaf
(Dec. 2010)
(Zero emissions) JC08 mode AC power consumption: 124Wh/km
Nissan Serena
(Nov. 2010)
All grades   All grades      
Nissan Elgrand
(Aug. 2010)
All grades   2.5L 3.5L・2WD
(2,020kg or
heavier)
3.5L・4WD All other
grades
Nissan March
(Jul. 2010)
All grades   All grades      
Nissan Juke
(Jun. 2010)
1.5L All other
grades
    1.5L All other
grades
Mazda Premacy
(Jul. 2010)
All grades   2WD + i-stop
(1,520kg or
heavier)
2WD + i-stop 2WD
(without i-stop)
All other
grades
Mitsubishi RVR
(Feb. 2010)
All grades       All grades  
Suzuki MR wagon
(Jan. 2011)
All grades   All other
grades
Turbocharged
・4WD
   
Suzuki Solio
(Dec. 2010)
All grades   All grades      
Suzuki Swift
(Dec. 2010)
All grades   All other
grades
  5MT  
Daihatsu Move
(Dec. 2010)
All grades   All grades      
Source: Environmental information by model published by respective automakers as of the end of February 2010
(Notes) 1. New models and fully-remodeled vehicles only (OEM supplies are not included).
2. The "eco-car tax" privileges introduced on April 1, 2009 to promote the use of green vehicles, include a 100% exemption of both the automobile weight tax and acquisition tax for hybrid vehicles that meet SU-LEV level (emission performance) and 2010 fuel efficiency standard at +25% level. Under the same taxation, 75% tax reductions apply to gasoline fueled vehicles that meet SU-LEV level (emission performance) and 2010 fuel efficiency standard +25% level; 50% reductions to gasoline fueled vehicles that meet 2010 fuel efficiency standard +20% and +15%. The privilege period lasts until the end of April 2012 (automobile weight tax) and the end of March 2012 (automobile acquisition tax).
3. The automobile "green tax" privileges include a 50% reduction of the motor vehicle tax for those vehicles that meet SU-LEV level and 2010 fuel efficiency standard +25% (the reduction applies to the year after the year of purchase; not applicable to minicars). The privilege period lasts until the end of March 2012.
4. The "eco-car subsidy" program (financial aid for the promotion of green vehicles) was introduced on April 10, 2009 and lasted until September 7, 2010. The program offered JPY250,000 to the vehicle owner that traded a 13 years or older vehicle with a new car that met the 2010 fuel efficiency standard (JPY125,000 for a minicar). Those owners that bought new vehicles without trading in the old car received JPY100,000 (JPY50,000 for a minicar) if the new vehicle met the SU-LEV emission performance level and 2010 fuel efficiency standard +15%.
5. The 2015 fuel efficiency standard announced in July 2007 includes an average fuel efficiency of 16.8km/L or higher for passenger cars (23.5% improvement over the result in FY2004) and a change of fuel efficiency testing method from the 10・15 mode to JC08 mode test run. Among the new passenger cars released in 2010 through January 2011, some of Toyota Passo cars, Lexus CT200h, Honda CR-Z, Nissan Serena, some of Nissan Elgrand and some of Nissan March meet the 2015 fuel efficiency standard.


Environmental measures: Increased availability of variable intake and exhaust valve systems and eco-drive assists

 Variable valve systems are used in all engines in the new passenger cars released in the domestic market in 2010 through January 2011. Most of the systems provide continuously variable timing control in both the intake and exhaust lines and are being adopted in minicars as well.

 Also increasing in availability as fuel efficiency enhancing measures are the "eco" lamp that goes on whenever the engine runs in low fuel consumption condition, the display of fuel efficiency as part of the odometer information, and certain other eco-drive assists. Another feature of increasing availability is the eco drive mode that controls the car's driving force and air conditioning in favor of fuel efficiency.

Toyota: Environmental measures in Toyota/Lexus cars released in domestic market in 2010 through January 2011

Model
(Month/Year
of release)
Technologies behind improved fuel efficiency,
exhaust gas purification and fuel-efficient-drive assists
Toyota Vitz
(Dec. 2010)
[Powertrain]
・The newly-used 1.3L Dual VVT-i (Note 1) engine is paired with the Super CVT-i with a torque converter of a broader lockup range and has 10-15 mode fuel efficiency of 24.0km/L (2WD).
・The start/stop system is combined with 1.3L・2WD models in Smart Stop package and gives 10-15 mode fuel efficiency of 26.5km/L, the lowest in its class.
[Emissions purification] Three-way catalysts and air-fuel ratio compensators are used.
[Fuel efficient-drive assists] The available multi-information display located within the instrument cluster shows information such as fuel efficiency, average fuel efficiency and possible cruising distance. The available Eco Driving Indicator turns on when the accelerator is operated in an environmentally-friendly manner.
Toyota Ractis
(Nov. 2010)
[Powertrain]
・The newly-used 1.3L Dual VVT-i engine is paired with the Super CVT-i to give 10-15 mode fuel efficiency ranging from 19.6 to 20.0km/L.
・The 1.5L VVT-i engine is paired with the Super CVT-i (highly responsive Active CVT system combining the 7-speed Sports Sequential Shiftmatic transmission and CVT Sport mode) to give 10-15 mode fuel efficiency of 20.0km/L (2WD) and 18.4km/L (4WD).
[Emissions purification] Three-way catalysts and air-fuel ratio compensators are used.
[Fuel efficient-drive assists] The Eco Drive Indicator that turns on when the accelerator is operated in an environmentally-friendly manner, and the switch-operated Drive Monitor that shows the average fuel efficiency are available on all models.
Toyota FJ Cruiser
(Nov. 2010)
[Powertrain] The 4.0L V6 engine is paired with Dual VVT-i and uses roller rocker arms to reduce frictions. Combination with 5-speed AT (5 Super ECT) and a part-time 4WD system gives 10-15 mode fuel efficiency of 8.4km/L.
[Emissions purification] Three-way catalysts and air-fuel ratio compensators are used.
Toyota Passo
(Feb. 2010)
[Powertrain]
・The 2WD model with the 1.0L VVT-i paired with CVT gives 10-15 mode fuel efficiency of 22.5km/L. The car meets "2010 fuel efficiency standard + 25%" and "2015 fuel efficiency standard."
・The 2WD model with the newly-installed 1.3L Dual VVT-i paired with CVT gives 10-15 mode fuel efficiency of 21.0km/L.
[Emissions purification] Three-way catalysts and air-fuel ratio compensators are used.
[Fuel efficient-drive assists] The Eco Drive Indicator that turns on when the accelerator is operated in an environmentally-friendly manner, and the switch-operated Drive Monitor that shows the average fuel efficiency is available on all models.
Lexus CT200h
(Jan. 2011)
[Powertrain] Equipped with a hybrid system, comprising the 1.8L Atkinson cycle engine (Note 2), motor and reduction gear, and a variable valve timing mechanism. The car gives 10-15 mode fuel efficiency of 34.0km/L and meets "2010 fuel efficiency standard + 25%" and "2015 fuel efficiency standard."
[Fuel efficiency enhancement] The exhaust gas recirculation system effectively reduces the engine warm-up time by using the exhaust heat to heat the coolant. The new humidity sensor detects the humidity, air temperature and windshield surface temperature and increases the ratio of inner air circulation accordingly to increase the heating efficiency without fogging the windshield.
[Fuel efficient-drive assists] The eco-drive support dubbed "harmonious driving navigator" is a real-time display of eco-friendly driving in the hybrid system indicator. The data are sent for storage to the center via Lexus' Telematics service for later reference and comparison with other drivers. The driver can also opt for "eco mode" where the driving power and air conditioning are put in energy saving control mode.
Source: Toyota's environmental information by model, new car announcement materials, on-line catalogs, etc.
(Notes) 1. The Dual VVT-i (Dual Variable Valve Timing-intelligent) optimizes not only the opening/closing timing of the intake valve but also that of the exhaust valve according to the driving condition.
2. The Atkinson cycle engine is designed to delay the intake valve closing timing, thereby making the expansion ratio higher than the compression ratio to increase the efficiency of combustion. This also reduces the pumping loss which, in turn, increases the fuel efficiency.

Honda, Nissan: Environmental measures in new passenger cars released in domestic market in 2010

Model
(Month/Year
of release)
Technologies behind improved fuel efficiency,
exhaust gas purification and fuel-efficient-drive assists
Honda Fit Hybrid
(Oct. 2010)
[Powertrain] The hybrid system comprises the 1.3L i-VTEC engine, lightweight, small IMA (Integrated Motor Assist) and the start/stop system. The car regularly runs on the engine and is assisted by the motor at starting and acceleration to minimize fuel consumption (parallel type hybrid system). The car has 10-15 mode fuel efficiency of 30.0km/L.
[Fuel efficient-drive assists] The ambient meter displays when the car is running in fuel efficient condition. The "Eco Assist" supports eco-driving. The driver can choose "ECON mode" where the engine, the transmission and air-conditioner are placed under coordinated control to favor fuel efficiency.
Honda Freed Spike
(Jul. 2010)
[Powertrain] The 1.5L i-VTEC (Note 1) engine features valve timing control and variable air intake amount control for optimal throttle valve control by DBW (drive-by-wire). This contributes to better fuel efficiency performances. The engine is paired with CVT with a torque converter (2WD) or five-speed AT (4WD) and the car gives 10-15 mode fuel efficiency of 16.4km/L (2WD) and 14.0km/L (4WD).
[Fuel efficient-drive assists] The current fuel efficiency, average fuel efficiency and possible cruising distance are shown in the information display within the cluster meter.
Honda CR-Z
(Feb. 2010)
[Powertrain] The CR-Z's hybrid system comprises the 1.5L i-VTEC engine, lightweight, small IMA (Integrated Motor Assist) and the start/stop system. The 1.5L i-VTEC engine has lowered fuel consumption by deactivating intake valves on one side when running in low speeds. This creates a stronger swirl in the combustion chamber which, in turn, causes lean combustion. The motor is used to assist the engine at starting and acceleration and delivers acceleration performance and low-speed torque that belong to 2.0L class engines. The CR-Z has 10-15 mode fuel efficiency of 25.0km/L (CVT model) and 22.5km/L (6MT model).
[Fuel efficient-drive assists] The "Eco Assist" that supports eco-driving and the "ECON mode" that controls the electronically controlled throttle and electric power steering in favor of fuel efficiency are standard on all models. The MT model has shift-up and shift-down indicators to prompt the driver to operate the gear and increase fuel efficiency.
Nissan Leaf
(Dec. 2010)
[EV powertrain] The lithium-ion battery (24kWh capacity, max. output over 90kW) and the electric motor (max. output 80kW, max. torque 280N・m) give a cruising distance of 200km (JC08 mode) per full charge. The car has an AC power consumption ratio of 124Wh/km and zero CO2 emissions.
[Fuel efficient-drive assists] The car features an "eco indicator" that shows the driver's eco-driving level, "eco-tree display" of cumulative data of the driver's eco-driving level, and EV-specific information communications system that supports the driver by displaying the expected area of reach and the locations of charging stations.
Nissan Serena
(Nov. 2010)
[Powertrain] The new 2.0L direct-injection MR20DD engine boasts high thermal efficiency resulting from direct fuel injection that ensures lower fuel consumption and higher torque at the same time. The use of the twin-VTC (Note 2) that increases the intake and exhaust efficiencies further increases the car's fuel efficiency. Pairing with the XTRONIC CVT and the start/stop system gives 10-15 mode fuel efficiency of 15.4km/L (2WD) and 14.4km/L (4WD).
[Fuel efficiency enhancing measures] Electric power steering and variable generation voltage control. The latter is a charge control system to the battery that lowers the generation voltage during acceleration to reduce the load to the engine, and increases the generation voltage during deceleration to control electric power generation of the alternator, thereby reducing the car's fuel consumption.
[Fuel efficient-drive assists] An advanced meter with a visual eco-drive assist shows real time fuel efficiency, average fuel efficiency, eco-drive navigator, start/stop time, the amount of saved fuel, etc.
Nissan Elgrand
(Aug. 2010)
[Powertrain] Powered by VQ35DE engine (3.5L model) or QR25DE engine (2.5L model), paired with XTRONIC CVT-M6 for a broader gear range and lockup from low ranges to reduce fuel consumption. The vehicle has 10-15 mode fuel efficiency of 9.8km/L (3.5L・2WD model) or 11.6km/L (2.5L・2WD model).
[Fuel efficiency enhancing measures] Measures include variable valve timing, electric pump-driven hydraulic power steering, and variable generation voltage control. The adaptive shift control provides optimal shift control in response to the driver's accelerator operation, driving conditions and driving environments.
[Fuel efficient-drive assists] A broad range of eco-drive assists include the navigation-coordinated shift system that gives optimal control of the engine brake and cuts the fuel supply more frequently according to the road information sent from the navigation system, and the ECO mode that contains accelerator compensation and total control of the CVT shifting schedule.
Nissan March
(Jul. 2010)
[Powertrain]
・Powered by the newly-developed 3-cylinder 1.2L HR12DE engine. The XTRONIC CVT with an auxiliary gearbox (two-stage shift) gives a broader gear ratio range, compact and lightweight pulley, and lower oil agitation resistance. This leads to approximately 30% friction reduction which, in turn, contributes to higher fuel efficiency.
・The start/stop system, standard on certain mass production models, has increased the car's 10-15 mode fuel efficiency by 2.0km/L to 26.0km/L. The driver can check the engine cut-off time and the amount of saved gasoline fuel on the display in the meter.
[Fuel efficiency enhancing measures] Measures include variable valve timing, electric power steering, variable generation voltage control (including deceleration energy regenerative charging function), a highly rigid and lightweight platform etc.
 Since FY2010, Nissan is promoting CO2 reduction drive in a two-pillar strategy: the ultimate eco-car (Zero Emission) and the engine evolution type eco-car (Pure Drive). The Pure Drive cars are powered by the existing engines with the addition of next-generation environmental technologies (start/stop, clean diesel, hybrid etc) to achieve the lowest fuel consumption in class. The new March is the first in the Pure Drive series of vehicles.
Nissan Juke
(Jun. 2010)
[Powertrain] The 1.5L HR15DE engine features a dual injector system in which fuel is injected from two injectors per cylinder to stabilize the fuel efficiency. Pairing with the XTRONIC CVT with an auxiliary gearbox (two stage shift) gives 10-15 mode fuel efficiency of 19.0km/L (1.5L model).
[Fuel efficiency enhancing measures] Variable valve timing (both intake and exhaust valves) and variable generation voltage control are employed.
[Fuel efficient-drive assists] Assists include fuel efficiency display, eco-drive assist service etc. The driver can select ECO mode that controls the engine, CVT, air-conditioner etc., in low fuel consumption mode to support eco-driving and improve practical fuel efficiency.
Source: Honda and Nissan's environmental information by model, new car announcement materials, on-line catalogs, etc.
(Notes) 1. The i-VTEC (intelligent-Variable valve Timing and lift Electronic Control system) in Honda Freed Spike regulates the amount of intake valve lift in two stages according to the driving condition while continuously varying the opening/closing timing of the intake valve.
2. The twin-VTC (Variable Timing Control) system has variable valve timing mechanisms in both the intake and exhaust sides.

Mazda/Mitsubishi/Suzuki/Daihatsu: Environmental measures in new passenger cars released in domestic market in 2010 through January 2011

Model
(Month/Year
of release)
Technologies behind improved fuel efficiency,
exhaust gas purification and fuel-efficient-drive assists
Mazda Premacy
(Jul. 2010)
[Powertrain] The direct-injection 2.0L engine is used in all 2WD models. The start/stop system "i-stop" is standard with certain grades. Paired with 5-speed AT (Activematic) on 2WD models, with 4-speed AT on 4WD models. Variable valve timing system on all engines. 2WD models equipped with i-stop give 10-15 mode fuel efficiency of 16.0km/L (15.0km/L for models with electric sliding doors).
[Fuel efficiency enhancing measures] Measures include the torque converter with lock-up mechanism, and electric pump-driven hydraulic power steering.
[Emissions purification] The single-nanocatalyst used in the emissions purification system cuts the amount of precious metal used in catalysts by 70%. The company uses a unique catalyst structure in which precious metals are embedded in the catalytic material to drastically reduce the amount of platinum, palladium, rhodium, and other precious metals.
[Fuel efficient-drive assists] The eco-lamp that goes on when the car is running in an eco-friendly manner, and the trip computer that displays the real time fuel efficiency and average fuel efficiency within the instrument panel, are standard on all models.
Mitsubishi RVR
(Feb. 2010)
[Powertrain] Continuously variable valve timing systems are employed in both the intake and exhaust lines. The 1.8L MIVEC (Note 1) DOHC 16-valve engine is paired with the 6-speed sports mode CVT to achieve 10-15 mode fuel efficiency of 15.2km/L (2WD) and 15.0km/L (4WD).
[Fuel efficiency enhancing measures] The deceleration energy regeneration system and the electric power steering system contribute to reducing friction in the engine.
Suzuki MR wagon
(Jan. 2011)
[Powertrain] The newly-developed R06A engine is a naturally-aspirated engine with VVT (Variable Valve Timing) system in both the intake and exhaust sides, first application among minicars (as of January 2011 survey by Suzuki). The turbocharged engine uses the VVT system on the intake side. Pairing with the CVT (Note 2) with a low-high auxiliary gearbox gives 10-15 mode fuel efficiency of 25.5km/L (naturally-aspirated 2WD) and 22.5km/L (turbocharged 2WD).
[Fuel efficiency enhancing measures] The built-in cooler heats the CVT hydraulic oil with the engine coolant. The effective use of a high-tensile steel sheet has reduced the vehicle weight by 30kg compared to conventional models (G・2WD・4AT model) to 790kg (G・2WD・CVT model).
[Fuel efficient-drive assists] The eco-drive indicator goes on when the car is running in the low fuel consumption condition.
Suzuki Solio
(Dec. 2010)
[Powertrain] Powered by the 1.2L intake and exhaust VVT engine, shared with the Swift, and CVT with low/high two-staged auxiliary gearbox. The base vehicle (2WD) has 10-15 mode fuel efficiency of 22.5km/L.
[Fuel efficiency enhancing measures] Measures include a neutral control that disengages the clutch automatically when the car stops in D-range, and tires with low rolling resistance. The effective use of high-tensile steel sheet has reduced the vehicle weight (base model) to 1,000kg.
[Fuel efficient-drive assists] The eco-drive indicator goes on when the car is running in low fuel consumption condition.
Suzuki Swift
(Aug. 2010)
[Powertrain] Powered by the newly-developed 1.2L intake and exhaust VVT engine and CVT with low/high two-staged auxiliary gearbox. The 2WD and CVT model has 10-15 mode fuel efficiency of 23.0km/L.
[Fuel efficiency enhancing measures] Neutral control disengages the clutch automatically when the car stops in D-range. The new model has a larger body size than the previous model, but the effective use of high-tensile steel sheet, along with minor modifications of the engine, transmission and interior, has reduced the vehicle weight by approximately 10kg.
[Fuel efficient-drive assists] The eco-drive indicator goes on when the car is running in low fuel consumption condition.
Daihatsu Move
(Dec. 2010)
[Powertrain]
・Models powered by the newly-developed second-generation 660cc KF engine paired with the CVT with the addition of the newly-developed start/stop system (ecoIDLE) give 10-15 mode fuel efficiency of 27.0km/L, best among gasoline-fueled cars (as of December 2010 Daihatsu survey, HEV excluded).
・The second-generation KF engine (with variable valve timing system) incorporates the i-EGR system that detects the condition of combustion using the ions within the combustion chamber to achieve a drastic reduction of pumping loss. The Move uses a plastic-made electronic throttle body to reduce the weight. The shape of the combustion chamber has been modified to increase the combustion efficiency while the piston shape, oil seals and chain, have been modified to reduce mechanical loss.
[Fuel efficiency enhancing measures] Measures include tires of low rolling resistance and LED stop-lamp and high-mounted stop-lamp of high power saving performance. Weight reduction of the shell body, instrument panel, door trim, CVT units etc., has led to approximately 35kg in weight reduction from the previous model.
[Fuel efficient-drive assists] "Eco-drive assist" that analyzes the driving conditions and guides the driver to fuel-efficient driving, the eco indicator that goes on when the car is running in a fuel-efficient condition, and "eco" drive mode that contributes to increased fuel efficiency through air-conditioner control to favor fuel efficiency.
Source:  Environmental information by model, new car announcement materials,
and on-line catalogs published by respective automakers
(Notes) 1. MIVEC (Mitsubishi Innovative Valve timing Electronic Control system) is a generic term for Mitsubishi Motors' engines with a variable valve timing mechanism that provides continuously optimal control of intake and exhaust valve timing.
2. The CVT with an auxiliary gearbox, used by Suzuki, is supplied by JATCO and also used by Nissan on March and Juke.

 



Increased availability of start/stop systems with a shorter engine restart time

 Use of the start/stop system is increasing as an effective way to increase fuel efficiency. Among the new vehicles released for sale in 2010 through January 2011, start/stop systems are available in the Toyota Vitz, Nissan Serena and March, Mazda Premacy, and Daihatsu Move. Systems with shorter engine restarting time (0.3-0.4 seconds) are more available than before to eliminate the awkward restarting feel.

 To reduce the restarting time, Toyota has adopted a permanently engaged starter while Nissan has adopted a belt-driven alternator in addition to the conventional restarting system. Mazda leverages on the principle of direct injection engines to ensure quicker and quieter restarting while Daihatsu has developed a lighter-weight, smaller and more cost effective system for minicars.

Models with start/stop systems released by Japanese automakers (2010 through January 2011)

  Name of system Model Engine Transmission Mileage
(10・15 mode)
Toyota SMART STOP Vitz 1.3L Dual VVT-i
1NR-FE
Super CVT-i 26.5km/L
Nissan Idling-stop
(ECO motor type)
Serena 2.0L direct-injection
MR20DD
XTRONIC CVT 15.4km/L
Idling-stop
(starter type)
March 1.2L 3-cylinder HR12DE XTRONIC CVT
with an auxiliary
gearbox
26.0km/L
Mazda i-stop Premacy 2.0L direct-injection
DOHC DISI
5-speed AT 16.0km/L
Daihatsu ecoIDLE Move 0.658L 3-cylinder KF CVT 27.0km/L

Source: Press releases and product information published by respective automakers

Toyota: Start/stop system with a permanently engaged starter available on Vitz
 In conventional starters, the pinion gear located at the tip of the starter moves forward and engages with the ring gear in the engine side to assist the engine starting. If the engine keeps running on inertia after the fuel supply is cut, the pinion gear will not move forward and will prevent the engine from restarting quickly when the driver tries to restart the engine before the engine reaches zero rpm.
 In the permanently engaged starter, jointly developed by Denso and Toyota, the starter's pinion gear is constantly meshed with the engine's ring gear. The ring gear incorporates a one-way clutch so that the starter can cause the ring gear to turn but not vice versa. This leads to 3% increase in fuel efficiency and an approximately 80% reduction of engine restarting time (0.35 seconds in the case of Vitz). The system has been launched in combination with MT in the European Auris etc., but the new Vitz represents the first combination of the system with CVT.
(Notes) 1. Denso exhibited, at the Detroit Auto Show held in January 2011, the Tandem Solenoid Starter (TS solenoid) that allows the engine to restart while it is running on inertia. Special software is used to move the pinion gear forward and engage it with the ring gear in synchronization with the engine's rpms. This creates the same effect as the permanently engaged starter without the addition of the clutch. Denso plans to start commercial use of the new system before the end of 2011.
2. Denso exhibited, in the Automotive Engineering Exposition held in June 2011 in Japan, the AE (Advanced Engagement) starter featuring improved durability over existing starters. A spring located at the tip of the pinion gear dampens the impact of meshing with the ring gear. The conventional starters normally last for approximately 30,000 starts. The new starter lasts ten times longer for 300,000 starts. It is used in vehicles released by Hyundai and VW in 2010.
Nissan: ECO motor type start/stop system used in Serena
 Nissan's Serena, released for sale in November 2010, features an ECO motor type start/stop system designed for quicker and quieter engine startability. The ECO motor (Energy Control Motor) consists of the alternator having engine restarting function in addition to the power generation and regeneration from deceleration energy.
 The belt-drive ECO motor ensures a faster restarting (approx. 0.3 seconds) as it turns the pulley, directly coupled with the crank, via the belt-drive mechanism. The system uses two crank angle sensors to identify the first cylinder to be ignited, thereby suppressing the variation of the restarting time and also ensuring a quiet restarting without the starter motor sound.
Nissan: Starter type start/stop system used in March
 In the conventional starter type start/stop system used in Nissan March, the starter's pinion gear starts turning and moves forward to engage with the ring gear and turn the flywheel which, in turn, causes the crankshaft to turn. This requires approximately 0.4 seconds of engine restarting time in the case of March.

(Note) Nissan reportedly plans to use the two types selectively; the starter type start/stop system on compact cars and the ECO motor type system (alternator doubling as the starter) on minivan or larger cost tolerant vehicles.

Mazda: Quicker and quieter engine restart technology leveraging on the principle of direct fuel injection
 The conventional system uses the starter motor alone to restart the engine. Mazda's i-stop system injects fuel directly into the cylinder of the idle engine to cause explosion and generate downward piston force to restart the engine. This not only saves fuel but also reduces the restarting time.
 The new process begins through precise control of the amount of air in each cylinder when the car comes to a stop to leave the pistons in the optimal positions when the engine is shut down. The system determines a specific cylinder into which fuel should be injected first and ignites that cylinder first and other cylinders sequentially. In this way the engine restarts after exactly the same timing at all times and the restarting time is nearly halved from that of the conventional starter motor type system to only 0.35 seconds (as measured by Mazda on AT models).
Daihatsu: Lightweight and down-sized start/stop system, ecoIDLE, featured in the Move
The Move launched in December 2010 features a new lightweight and compact start/stop system, ecoIDLE, with the fewer system-specific component count. Compared to the conventional system used in Mira since December 2006, the new one has reduced the system weight by 60% to 4kg and the engine restart time by 0.1 second to 0.4 seconds along with 70% cost reduction.
 The electric oil pump for CVT in the conventional system was eliminated through the introduction of Daihatsu's original CVT hydraulic technology and faster engine restart technology. The new system has a start/stop computer incorporated with the auxiliary power unit to prevent the navigation and audio systems from resetting each time the engine restarts. The sub-battery used in the conventional system to prevent voltage drop was eliminated as a result.
(Note)  Daihatsu plans to install the start/stop system in all minicars by 2012 starting with the new model "e:s" being launched in the summer of 2011. The system will be installed in other cars at the time of their full modification or minor changes.
Source: Press releases, new car announcement materials, and on-line catalogs published by respective automakers

<Automotive Industry Portal MarkLines>