The list of Toyota hybrid transmissions would be incomplete without mentioning the commercial models.
The very first Hino diesel hybrid bus ('parallel type mild hybrid'). The motor-generator integrated with flywheel was used for recovering energy during braking and assisting the diesel engine during acceleration. Engine - initially equipped with M10U (9.9l, 235 hp / 716 nm), later replaced by J08C type (240 hp, 735 Nm). Electric motor - 3-phase AC type (30 kW). Battery - a pack of 25 lead-acid batteries.
Parallel type mild hybrid shuttle/tour bus, equipped with P11C engine (310 hp) + three-phase AC induction motor. Since 2005 a NiMH battery used instead of the lead-acid one.
This is a minibus for 20-25 seats in excursion performance, built as series-PHEV. The chassis and body of a conventional HZB50 are the base, but the powertrain turned out to be completely unique.
Electric motor (70 kW / 405 Nm) drives the rear wheels. For energy storage, a complex of 24 lead-acid 12-volt batteries (58Ah each) was used, providing a total voltage of 288V. Recharging is carried out by a special external 30A charger.
The well known petrol engine 5E-FE (1.5) derated to 49 hp rotates a power generator (25 kW) - obviously a normal driving by its energy only is impossible. However, when the batteries are fully charged and there are 95 liters of fuel in the tank, the manufacturer declared a total range of 400-500 km in city mode.
The high cost and problems in winter conditions did not contribute to the popularity of this version, but its production continued until 2007.
Next generation of parallel type mild hybrid city bus, equipped with J08C-1M engine (8.0l 240 hp / 735 Nm) + 1M motor-generator (41 kW). Reduced size of the batteries and electrical equipment made it possible to lower the floor ('one-step' class).
In 2005, Toyota introduced its first parallel diesel-electric hybrid. It is based on the N04C engine (4.0, 150 hp), the flywheel of which is integrated with the rotor of a compact electric motor (36 kW / 350 nm). Transmission - 5MT (H351, M550) or 6AT (A860E). The NiMH battery pack (similar to the first Prius) and the inverter are located in the place of the conventional left fuel tank. In addition, the advanced exhaust gas aftertreatment system was emphasized at that time.
There are several operation modes of the hybrid system:
· Start-off and acceleration - simultaneous operation of the internal combustion engine and the electric motor
· Normal driving - only the diesel operates
· Deceleration and braking - the motor operates as generator to recover energy and charge the battery
· Idle stops - automatic diesel turn-off
· Power take-off (PTO) - electric motor could be used
Since 2005, a less known version of the medium-duty Hino Ranger has been produced.
Modernized version of parallel type mild hybrid city bus, equipped with J08C-1M engine (8.0l 240 hp / 735 Nm) + 1M motor-generator (41 kW), later J08E-1M engine (7.7l, 280 hp). The pack of lead-acid batteries have been replaced with 4 NiMH batteries of Prius (13 Ah, 403 V). Batteries and compact inverter were installed on the roof, which made it possible to further lower the floor ('non-step' class).
In the 2000s, there were some experiments to 'hybridize' commercial kei-cars. Internal combustion engine - EF-VE (0.66, 37 kW), transmission - 4AT, a compact electric motor (9.4 kW / 46 nm) with air cooling is sandwiched between them. Battery unit (NiMH 6.5Ah) located under the second row seats. Some components from Estima Hybrid are used.
It is a usual parallel hybrid scheme: the electric motor operates together with ICE when starting off and under high load, doesn't operate during steady driving, acts as a generator during regenerative braking, starts the ICE from idle-stop mode.
Even though the manufacturer declared the possibility of reducing fuel consumption by 25%, however, the very high price (1.5-2 times more expensive than standard kei-LCV) repelled even gov-organizations and municipalities, not to mention owner-operators.
Parallel type mild hybrid bus, equipped with A09C-1M diesel engine (8.9l, 350 hp / 1569 Nm) + 29 kW electric motor-generator.
During the truck generation change the hybrid system was also changed. The motor-generator, placed in a separate unit, is now integrated with the transmission, and, on the contrary, is separated from the engine by the clutch.
Transmission - only automated manual (5-AMT based on M550, then 6-AMT RE60 / RE62). The engine is of the same N04C family (4.0 150 kW / 440 nm). Electric motor - 35 kW / 420 nm.
Due to the new design, additional modes appeared:
· Start-off or driving with a light load - by electric motor traction only.
· Deceleration / braking with clutch released for maximum energy recovery.
Limited-production plug-in hybrid bus. Engine - J07E (6.4, 169 kW / 657 nm), transmission - 6-AMT, electric motor - 175 kW, battery - 40 kWh (355 V / 112 Ah). The specific layout of the components is noteworthy, with a separately installed motor-generator, two propshafts and a transfer case.
The hybrid system is used only to power the electric refrigeration compressor, without drive torque assist function. While deceleration (1), 36 kW generator charges the NiMH hybrid battery and supplies electricity to the refrigerator. While acceleration, or steady running, or idling stop (2) - engine power is used by generator and electricity is supplied directly to the refrigerator. When the engine is stopped (3) the refrigerator can be driven by connecting an external power supply.
City buses of Blue Ribbon family received mild-hybrid versions early, but the full hybrid version appeared in the last generation. The principle of operation is similar to modern hybrid trucks, taking into account the rear-engine layout traditional for buses. Engine - A05C (5.1l, 191 kW), transmission - 6-AMT, electric motor - 90 kW. The high-voltage battery is located on the roof and, in addition to the hybrid system, feeds the air conditioner.
· Diesel engine starting by the electric motor (clutch engaged).
· Start and low-load driving with electric motor only (clutch disengaged).
· Joint operation of the internal combustion engine and the electric motor during acceleration or under heavy load.
· Steady driving with the internal combustion engine only.
· Regenerative braking (clutch disengaged, diesel idling).
· Engine automatic stall at stops (idle stop)
In the second half of the 2010s, full-fledged hybridization reached a heavy trucks segment. The concept is similar to Dyna/Dutro, but upscaled accordingly: engine - A09C (8.9, 280 kW), transmission - 12-AMT MZ12, electric motor - 92 kW, Li-ion battery has a capacity of 11 kWh.
Refrigerators without an auxiliary ICE are considered one of the main applications of a heavy hybrid - HV battery capacity should provide several hours of operation of an electric compressor.