The development of diesel powertrains have appeared to be sidelined by that of petrol-electric hybrids and fully electric powertrains in the shift away from reliance on petrol, though now the rumour mill spins with petrol-electric hybrid stalwart Toyota said to be developing diesel hybrids, according to Best Car Web.

Toyota is aiming to expand its model line-up with hybrid powertrains as soon as possible, with the aim of minimising or eliminating purely internal combustion powertrains where possible, according to the Japanese site. This type of powertrain is expected to see service in “off-road 4WD vehicles” and commercial vehicle-based models, the report added.

This, in combination with other petrol-electric powertrain combinations, will serve to make all Toyota passenger vehicle models hybrids, followed shortly after by the commercial vehicle models such as vans and light trucks, suggested Best Car Web.

The new diesel hybrid powertrains are likely to serve in 4WDs – such as the Land Cruiser – and light commercial vehicles

The most likely candidates which suit the description would be the Land Cruiser and Land Cruiser Prado, the former launched with a 415 PS/650 Nm 3.5 litre turbo petrol V6 and a 309 PS/700 Nm 3.3 litre turbodiesel V6. Heavier vehicles such as 4WDs and commercial vehicles would benefit from the pairing of electric drive with diesels, resulting in greater torque that is accessible at low engine speeds.

The report is so far unconfirmed by official Toyota sources, and it remains to be seen if the diesel-electric pairing will adopt a configuration similar to that of the petrol-engined Toyota Hybrid System-II layout.

The report also notes that current passenger vehicle models in the Japanese line-up currently without hybrid powertrains include the Land Cruiser, Land Cruiser Prado, Hiace Wagon, GranAce and others, and development of these models is said to incorporate 2.5 litre and 3.5 litre hybrids in the future.

Pairing diesel with electric drive has recently been adopted by Jaguar Land Rover, which has the 3.0 litre Ingenium mild-hybrid diesel setup. More alike Toyota’s parallel-hybrid system in diesel form would be the W212 Mercedes-Benz E 300 BlueTec Hybrid, which went on sale in Malaysia in 2015.