2011 Automotive Engineering Exposition: Parts Suppliers (1)

Exhibits related to EV/HEV and start-stop system technologies



 Reported below is an outline of exhibits of Electric vehicle and Hybrid electric vehicle (EV/HEV) and start-stop system technologies displayed by automotive parts suppliers at the 2011 Automotive Engineering Exposition (May 18-20, 2011, Yokohama) organized by the Society of Automotive Engineers of Japan, Incorporated.

 Exhibits of EV/HEV systems included the in-wheel motor system by NTN, 7-speed Automatic Transmission (AT) based hybrid transmissions by JATCO and 8-speed AT based hybrid transmissions by ZF Sachs.

 The exposition was characterized by, among others, many parts designed to support the smooth driving of EVs having no internal combustion engine and HEVs whose internal combustion engine is deactivated as needed. These included electric oil pumps and electric water pumps displayed by Aisin Seiki and Hitachi. As for brake systems, Hitachi and Hella exhibited devices that generated negative pressure normally supplied by the engine.

 Mitsubishi Heavy Industries exhibited electric water heaters used for heating the i-MiEV's compartment. Calsonic Kansei is developing a power-saving heat pump type air conditioner.

 Start-stop systems present a challenge common to EV and HEV associated with the deactivation of the engine. Exhibits addressing this problem included DC-DC converters designed to stabilize the restarting voltage, and electric oil pumps that send oil to the transmission needed to generate enough hydraulic pressure for restarting. Advics exhibited start-stop system cooperative brake control that automatically maintains the brakes while the vehicle is at standstill with the engine deactivated.

EV/HEV systems on display

 In March 2011, NTN announced the company had developed the world's lightest "in-wheel motor system" having a built-in control system that worked hand-in-hand with sensor information. The new system was displayed at the exposition along with its two variations, the on-board drive system and the one-motor EV drive system.

 Mitsubishi Heavy Industries had panels outlining its electric bus demonstration tests that were conducted in February to March 2011. JATCO exhibited the Hybrid transmission used on Nissan's Fuga Hybrid. ZF exhibited a Hybrid transmission that had a hybrid module located within the space normally occupied by a torque converter in the 8-speed AT.

In-wheel motor system exhibited by NTN
In-wheel motor system exhibited by NTN

NTN's one-motor EV drive system
NTN's one-motor EV drive system (similar to other EVs but incorporates an automated
two-stage shift mechanism to accommodate a small high-speed motor)

8-speed hybrid transmission exhibited by ZF Sachs
8-speed hybrid transmission exhibited by ZF Sachs
(used on hybrid vehicles by BMW, Mercedes-Benz and Audi)

EV/HEV systems

NTN's in-wheel motor system - Proposals and test vehicles
Motor System
Basic concept  The motor and reduction gear are placed inside the wheel. Since driving force is transmitted directly to the tire, energy loss at the gear or driveshaft is minimal. The system also contributes to reducing vehicle weight and increasing interior space. It permits such maneuvers as parallel movement and pivoting.
Compact class EV  A cycloidal reduction gear with a very high reduction rate of "11" was used to develop the world's lightest EV system (according to NTN). The system is used in two wheels (rear or front) to get the same driving performance as a 1500cc-class compact car along with 150km/h maximum speed and 300,000km durability.
electric commuter
 NTN developed compact motors and reduction gears to meet specific functions and usages of two-seater electric commuter or one-seat minicar. A two-seater experimental vehicle was exhibited.
Two variations On-board drive system  To keep the advantages of the in-wheel motors and leave the existing vehicle platform intact as much as possible, NTN placed two motors, of the same type as the in-wheel motors for compact class vehicles, at the center of the vehicle and connected them with the wheels via constant-velocity joints and hub bearings. The two motors drive the wheels independently with a maximum speed of 150km/h. The system can easily be used in conversion EVs.
 The experimental vehicle (displayed as a concept model, according to NTN) had an on-board drive system on a Suzuki Wagon R body.
One-motor EV
drive system
 This is a type of single-motor drive system that has become the mainstream among today's EVs which have to use a large drive motor since most EVs use a reduction gear that has no shifting mechanism. NTN adopted an original automatic two-stage shifting mechanism so that the compact, high-speed motor can be used efficiently under a broad range of conditions of the EV. The result is a compact, lightweight system.
Mitsubishi Heavy Industries' electric bus
Electric bus
demonstration tests
 Panels were exhibited outlining the electric bus demonstration tests that were conducted in Kyoto City and Aomori City in February-March 2011. Mitsubishi Fuso Aero Star Eco Hybrid Bus was converted to an electric bus powered by the company's lithium-ion MLiX batteries. The serial type EV driven by motors has a cruising range of 30km (JE05 mode, all seats occupied, without air conditioning) plus 10km of emergency travel. Quick charge in 60 minutes. The company plans to develop a production model of the electric bus.
 Mitsubishi Heavy Industries' intention is to develop infrastructure for a low-carbon society with electric buses in addition to selling its lithium-ion batteries. Batteries reaching expiry on vehicles may be reused as a source of electricity in other applications such as community events and disaster-relief activities.
Hybrid transmissions
JATCO 7-speed hybrid
 The 7-speed AT-based hybrid transmission used on Nissan Fuga Hybrid is a 1-motor 2-clutch system without a torque converter. It has four driving patterns to choose from: (1) Motor-driven mode at starting or in high battery condition, (2) Engine-driven mode in low battery condition while turning the motor to charge the batteries, (3) The engine disengaged for deceleration to regenerate the brake energy, and (4) Driven by both the engine and the motor for full-throttle acceleration.
 The first of the two clutches is located between the engine and the motor. When it is disengaged, the vehicle runs on the motor alone or regenerates braking energy efficiently. The second clutch is a generic term for a set of wet clutches located in the 7-speed AT and functions as conventional shift gears (the second clutch is always "ON" and meshed with one of the seven-speed gears).
 JATCO has replaced the torque converter with wet clutches that enable smooth shifting of the 7-speed AT, and with motor assists. The Fuga gasoline model also uses wet clutches but it requires torque amplification from the torque converter as it does not have motor assist.
ZF Sachs Rear-wheel drive
8-speed hybrid
 The wet clutches, electric motor and torsional dampers are housed in the space, originally occupied by the torque converter of the ordinary 8-speed AT, without modifying the overall size. The system may be used in a mild HEV, full-time HEV, micro HEV (start-stop system) etc. Designed carefully to accommodate varying combinations with up to 200 motors.
 Already used in BMW 7 Series Active Hybrid, Mercedes-Benz S400 BlueHybrid and Audi Q5 Hybrid, and in Audi A6 Hybrid launched in the spring of 2011. Land Rover plans to release Range Rover Sport-based plug-in hybrid electric vehicle (PHEV) "Range_e" in 2013 featuring the hybrid transmission described above.

Source: Displays and brochures at the Exposition, and the suppliers' announcements (for this and all other sections below)


Batteries, capacitors, motors

 Hitachi exhibited LIB-II and LIB-III generation lithium-ion batteries currently being manufactured in large volumes, and LIB-IV lithium-ion batteries for Plug-in hybrid electric vehicle and Electric vehicle (PHEV/EV) currently being developed. Shin-Kobe Electric Machinery exhibited large-size cylindrical lithium-ion capacitors, the development of which was announced in February 2011.

 SB LiMotive, jointly formed by Bosch and Samsung SDI, exhibited lithium-ion batteries for PHEV application.

 Bosch exhibited two types of motors for hybrid systems, the separate type externally added to the powertrain and the integral type located between the engine and the transmission.

Lithium-ion capacitors exhibited by Shin-Kobe Electric Machinery
Lithium-ion capacitors exhibited by Shin-Kobe Electric Machinery
(Shin-Kobe has also developed modules coupled with lead batteries and lithium-ion batteries)

Batteries and motors for EV/HEV application

by Hitachi
LIB-II  Designed for commercial HEVs
LIB-III  Supplying for "eAssist" systems released by GM in 2011
LIB-IV  Batteries for HEV use currently being developed with a goal of 4,500W/kg specific power (compared to 3,000W/kg realized by LIB-III)
For PHEV/EV  Being developed with a goal of 120Wh/kg specific energy. It is said specific energy is critical to batteries for EV/PHEV use to increase the range (LIB-IV batteries have specific energy of 72Wh/kg).
SB LiMotive Lithium-ion
for PHEV
 SB LiMotive, a lithium-ion battery manufacturer formed jointly by Bosch and Samsung SDI in 2008, exhibited lithium-ion battery (model) for plug-in hybrid systems in Bosch's booth. The company has not disclosed the customer for the batteries.
Li-ion capacitors  Shin-Kobe Electric Machinery has developed large, cylindrical lithium-ion capacitors having cathodes that are made of activated carbon used in EDLC (electric double layer capacitor) and anodes that are made from the same carbon material used in lithium batteries. The capacitors have higher short-time charge/discharge performances than lithium-ion batteries and higher specific energy and operating voltage than EDLC.
 The capacitors will serve as storage devices for such applications as hybrid construction machinery, unmanned transporters, auxiliary power supply for start-stop systems, and electric energy regeneration. The company has also developed modules that combine them with lead storage batteries and lithium-ion batteries.
 Shin-Kobe will develop new products having 1.5-fold more power or 1.7-fold more energy for release in the second quarter of 2011.
(Notes) 1. Capacitors store electric energy by absorption and desorption of ions in an electrolyte rather than by chemical reaction as in secondary batteries. For this reason, their storage capacity is smaller than the secondary batteries but they present a number of advantages such as short-time charge and discharge performances and higher resistance against deterioration due to charge and discharge.
2. A lithium-ion capacitor requires "spare lithium ions" to be charged in anodes to increase its performance, and this presents a major obstacle to making such capacitors for commercial use. Shin-Kobe solved this problem with new technology.
3. The "eAssist" mild hybrid system used in Buick LaCrosse released by GM in 2011 and other vehicles uses Hitachi's lithium-ion batteries LIB-III. They also use Maxwell's Ultracapacitors as an auxiliary power supply.
Motors for HEVs
Bosch Separate type
motor generator
 The Separated Motor Generator (SMG) can be added to an existing powertrain and is a smaller and lighter drive motor compared to the integrated type. This makes it ideal for use as a belt-driven motor or on DCT transmission-type hybrid vehicles. The SMG can deliver up to 250 Nm torque and approximately 50 kW power.
Integrated motor
 The Integrated Motor Generator (IMG) is a water-cooled motor assembled between the engine and the transmission of a parallel hybrid vehicle. The IMG can deliver up to 50 kW power and 350 Nm torque. Currently used on VW Touareg/Porsche Cayenne hybrid vehicles.


Electric pumps that replace engine-driven pumps

 Aisin Seiki and Hitachi exhibited electric pumps that supply cooling water to the engine and oil to the transmission, replacing the conventional engine- and belt-driven pumps.

Electric oil pumps and water pumps to support EV/HEV systems

Aisin Seiki Electric oil pump
for cooling motors
 Used on Lexus LS Hybrid and /HS250h/RX Hybrid and Toyota Highlander Hybrid to supply oil for cooling the motors fitted inside the transmission. The motor, pump and electric control circuitry are integrated into a compact design.
Electric water pump
for cooling engines
 Aisin Seiki is the first Japanese manufacturer to develop an electric water pump which is now used on Toyota's third-generation Prius released in May 2009. Compared to the conventional engine-driven pumps, the electrically driven type is activated only when it is needed to give optimum cooling while reducing the engine load. It contributes to a 2% improvement in fuel efficiency when used on a 1800cc gasoline engine vehicle.
Electric water pump
for cooling inverters
 Used on such hybrids as Lexus LS/GS/RX Hybrid, Camry Hybrid, Estima Hybrid and third-generation Prius. The motor, pump and electric control circuitry are integrated into a compact design. More pumps are being developed in varying capacities from small (10L/min) to large (100L/min).
Hitachi Electric oil pump  Hitachi has developed an auxiliary electric oil pump to maintain necessary hydraulic pressure in the transmission while the engine is deactivated. Silent operation was the most important development theme as it is activated when the engine is inactive. The motor has 200W power output.
(Notes) 1. Hitachi's electric oil pump has been used on Nissan Fuga Hybrid since 2010. According to Aisin Seiki, such an oil pump is normally necessary on HEVs based on gasoline-fueled vehicles but not on Toyota's HEV system (generally known as electric continuously variable transmission: ECVT) as the system is capable of maintaining hydraulic pressure necessary for the transmission when the engine is inactive.
2. According to Aisin Seiki, the three pumps listed above can be used on both the gasoline-fueled vehicles and HEVs alike although they are used today mainly on HEVs.


Air conditioning systems for EV/HEV

 Denso and Mitsubishi Heavy Industries exhibited electric compressors for EV/HEV use.

 Cabin heating is one of the main challenges in developing electric vehicles as heat is normally supplied by an internal combustion engine. In addition, heating has a direct impact on the driving range of an electric vehicle. Mitsubishi Heavy Industries exhibited an electric water heater currently being supplied for Mitsubishi's i-MiEV. The company is also developing automotive air conditioning systems by heat pump technology addressing electric power saving.

 Calsonic Kansei had panels showing a heat pump type air conditioning system being developed.

Mitsubishi Heavy Industries' electric compressor supplied to Mitsubishi i-MiEV and Chevrolet Volt
Mitsubishi Heavy Industries' electric compressor supplied to Mitsubishi i-MiEV and Chevrolet Volt

Mitsubishi Heavy Industries' electric water heater used on Mitsubishi i-MiEV
Mitsubishi Heavy Industries' electric water heater used on Mitsubishi i-MiEV

Air conditioning systems that support EV/HEV systems

Denso Electric compressor
for air conditioning
systems on EV/HEV
 The conventional, engine-driven A/C compressors cannot be used on either EV or HEV running in battery-driven mode. Denso, jointly with Toyota Industries Corporation, has developed the world's first automotive electric compressor integrating the motor and the inverter applicable to volume production. When used on an HEV, the new product contributes to up to a 19% improvement in fuel efficiency compared to the conventional belt-driven counterpart (while running with the cooler activated). The electric compressor is available in three variations ranging from small to luxury classes.
Electric compressor  Used on Mitsubishi i-MiEV. The inverter-integrated compressor follows the scroll compression method and uses R134A refrigerant. According to Mitsubishi Heavy Industries, the electric compressor is being supplied to Chevrolet Volt as well.
Electric water heater  Used on Mitsubishi i-MiEV. The L250mm×W110mm×H85mm heater has a dry weight of 5.4kg and 5.0kW capacity.
 Electric water heating saves development costs as all parts other than the heater itself can be taken from existing production cars. But it requires much electricity and reduces the car's running range when the heater is turned on. Mitsubishi Heavy Industries is also developing a heat pump type automotive air conditioning system capable of energy saving from 20% (at outside air temperature 0°C) to 60% (at 10°C) (not exhibited at 2011 Exposition but announced in Mitsubishi Heavy Industries' Technical Review No. 2, 2011).
Heat pump type
air conditioning
 According to Calsonic Kansei, air-conditioning consumes more electricity than driving does in cold climates. The heat pump type A/C system was announced during the 2010 Automotive Engineering Exposition and introduced at this year's Exposition on panels showing the system under development with the goal of 70% saving of electric consumption at outside air temperature 0°C.
 The system has two modes. The "fresh air heat pump" mode addresses electric energy saving while "recirculation air heat pump" mode addresses dehumidification not easily achievable in the first mode.


Systems that support brakes on EV/HEV

 Brake boost by the engine's negative pressure is not available on either EV or HEV while the engine is deactivated. Negative pressure must be supplied alternatively, for instance, by electric pumps as exhibited by Hitachi and Hella.

 Hella exhibited the conventional UP28 vacuum pump that provides complementary supply of negative pressure, and the new UP30 model that provides constant supply of negative pressure for brakes on electric vehicles, etc.

 NHK Spring exhibited an accumulator that stores and supplies hydraulic pressure to the brake. The product reportedly will be used on HEVs being launched in 2011 in Japan and overseas.

Electrically Driven Intelligent Brake by Hitachi and used on Nissan Fuga Hybrid and Leaf EV
Electrically Driven Intelligent Brake by Hitachi and used on Nissan Fuga Hybrid and Leaf EV

Vacuum pump UP30 exhibited by Hella
Vacuum pump UP30 exhibited by Hella

Accumulator developed by NHK Spring
Accumulator developed by NHK Spring

Systems that support brakes on EV/HEV

Hitachi Electrically Driven
Intelligent Brake
 Officially called Electrically-Driven Intelligent Brake with Regenerative Braking System for HEV and EV. Unlike the conventional brake boosters that require engine-generated negative pressure, the electric brake system uses an electric motor for use on EVs that do not have engines. It is used on the Nissan Fuga Hybrid and Leaf EV.
 The electric brake controller calculates a variance between the necessary braking force and regenerative braking, generates enough hydraulic pressure to fill the variance and supplies the pressure to the brake. The VDC's backup function ensures a high level of safety for the vehicle. This brake system adjusts the hydraulic pressure of the friction brake in such a way the brake energy regeneration is maximized while securing the necessary braking force in a natural feel.
 Since the braking force can be controlled freely by means of the motor control, Hitachi claims the electrically-driven intelligent brake can be used to control automatic brake and other advanced ITS brakes (Note 1).

(Note) ITS stands for Intelligent Transport System. An ITS braking system works in coordination with road infrastructural information.

Hella Vacuum pump  The newly-developed UP30 Vacuum Pump produces negative pressure and supplies it to the brake booster on EV and HEV where or when negative pressure from the engine is not available. The pump on display weighs about 1.7kg and lasts for 1.2 million switching operations or 1,200 hours.
 In Japan, the pump is used on Suzuki's Swift Range Extender (PHEV) currently in road tests. It was also supplied for Subaru Stella EV released in June 2009 by Fuji Heavy Industries.
 Hella also exhibited the UP28 Vacuum Pump, 11.5 million units of which have been sold since 1999. The UP28 is an on-demand type pump for starting in cold climates where not enough negative pressure is available. It is smaller than UP30, weighs 1kg and lasts for 450,000 switching operations or 600 hours.
NHK Spring Accumulator  The accumulator developed by NHK Spring is designed to store and supply high hydraulic pressure to brakes on each wheel to increase braking force when the brake pedal is depressed. Since it uses pressurized brake fluid, the accumulator is highly responsive and reduces the frequency of pump and motor operations, thereby extending their lives. It has a metal bellows-like structure inside (like the blower in a musical organ).
 Usable on EV/HEV where negative pressure from the engine is not available. The pressure from the accumulator may be regulated to control the braking hydraulic pressure for better coordination between regenerative and hydraulic brakes. Reportedly to be used on HEVs slated for launch in Japan and overseas in 2011.


Start-stop system technologies

 The use of start-stop system is increasing very rapidly as reflected in the exhibits of technologies addressing smoother and more stable start-stop operations.

 Denso exhibited the Tandem Solenoid Starter (never pre-released in Japan) capable of restarting after the engine is deactivated but running by inertia. Denso plans to put the technology to commercial application within 2011.

 Toyota Industries and Hella exhibited DC-DC converters (Toyota Industries calls them Voltage Stabilizers) designed to stabilize electric voltage for restarting the engine.

 Aisin Seiki and Hitachi exhibited an electric oil pump that maintains working hydraulic pressure of the transmission while the engine is deactivated (interruption of oil feed to the transmission when the engine is deactivated causes delay in startup).

Tandem Solenoid Starter by Denso
Tandem Solenoid Starter by Denso
(pinion plunger solenoid and motor energizing solenoid located at the top)

"Voltage Stabilizer" (DC-DC converter) for start-stop systems by Toyota Industries
"Voltage Stabilizer" (DC-DC converter) for start-stop systems by Toyota Industries
(reference exhibit)

"Electric Oil Pump for Start-Stop" by Aisin Seiki
"Electric Oil Pump for Start-Stop" by Aisin Seiki

Technologies related to start-stop systems

Denso Tandem Solenoid
 The tandem solenoid starter makes a start-stop system capable of restarting the engine while it is deactivated but turns by inertia, thereby reducing the start-up time and eliminating awkward moments. Exhibited at 2011 Detroit motor show, it has never been exhibited before in Japan.
 The conventional starters use a pinion plunger to energize the motor (into a rotational motion). This means the motor is engaged with the ring gear only in standstill state. The new starter has two solenoids to control plunging and rotation separately so as to force the pinion into mesh with the ring gear while controlling the speed of the pinion revolution according to the speed of the ring gear, thereby restarting the engine while it is rotating.
NSK One-way clutch  Toyota and Denso have a start-stop system called "Permanently Engaged Starter" that enables quick restart as does the tandem solenoid starter described above. Their product is used on European version of Auris etc. This starter is unique in that the ring gear and the pinion gear are permanently meshed.
 NSK exhibited a one-way clutch used in a permanently engaged starter. Once the engine is restarted, the ring gear is disengaged from the engine in motion (the engine itself requires a special design to implement a permanently engaged starter).
ADVICS Start-stop system
brake control
 Used on vehicles with a start-stop system. It automatically maintains the brake pressure while the car is at a standstill to prevent ride-down (due to loss of braking force) or start-up shock (when the engine restarts in D range). Used on Daihatsu Move and Suzuki MR Wagon with a start-stop system.
Batteries for
start-stop systems
 Use of high-density active material has increased the battery life three folds compared to the company's conventional batteries along with 1.5-folds more input characteristics as a result of using new additives. Quality warranty for 18 months or 30,000km. Used on the new Nissan March released in 2010.
DC-DC converter
 Officially called Voltage Stabilizer. In a start-stop system, a large current is sent to the starter when the engine restarts and the battery voltage drops as a result. The DC-DC converter stabilizes voltage supply to audio, navigation, meters and other on-board equipment to prevent interruption.

(Note) Toyota Industries has been supplying DC-DC converters for Toyota Prius Hybrid.

Hella DC-DC
 Supplies stabilized voltage to such loads, susceptible to low voltages in vehicles with a start-stop system, as the car navigation display, illuminations and audio systems. Hella has produced more than 9 million units of DC-DC converters and other voltage stabilizing devices since 2002.
Aisin Seiki Electric oil pumps
for start-stop
 Designed to maintain necessary transmission pressure and prevent start-up delay when restarting the engine in a start-stop system. Used on Toyota Vitz, Nissan March/Serena and Suzuki Wagon R. Developed in a series ranging from small capacity (supplementary hydraulic pressure for CVT) to large (AT hydraulic pressure control).
 Most of the pump components have the same structures as the afore-mentioned electric oil pump for cooling motors.
Hitachi  Hitachi is currently developing an electric sub-oil pump for supplying working pressure to the transmission while the engine is deactivated. The motor output is 30W. Silent operation is the most important requirement as it is activated when the engine is inactive.

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