Toyota is developing a family of turbo-petrol engines with larger and smaller capacities than the 2.0-litre unit unveiled on the Lexus stand at the Tokyo motor show this week.
Employing a claimed world first integrated cylinder head and a new generation VVTi variable valve system, the engine family also seems sure to become part of a plan for ‘performance’ petrol-electric hybrids for luxury brand Lexus and sportier models in the Toyota lineup.
The engine debuted in the LF-NX compact SUV concept in Tokyo and will first go on-sale late in 2014 in the production version of that vehicle. The car is expected to be badged NX and the engine - which will be the first turbo used in a Lexus - will be the 200t.
Engines from the new family will then flow into other Lexus models and into the Toyota range.
Little technical information was released in Tokyo and no outputs confirmed, however Lexus group manger engine product design Teru Ogawa told motoring.com.au that a family of engines was being developed.
Asked what capacities would be offered, he said “both larger and smaller”. He also said the target was beating the performance and refinement of engines produced by Lexus’ German rivals, such as BMW’s N20 turbo four.
Although the engine is based on the 2.5-litre AR four-cylinder unit, Ogawa said a new crankcase aided low noise, vibration and harshness levels, as do contra-rotating balance shafts. He would not state fuel consumption targets but confirmed the engine had been developed with stop-start capability.
The integrated cylinder head design twins exhaust port one with four and two with three inside the cylinder head and then feeds them separately into the twin scroll turbocharger.
“The fact that you have this integration into two ports here inside the cylinder head is a world premiere,” Ogawa explained through an interpreter.
The dual port exhaust provides for a smoother and faster exhaust flow into the turbocharger, virtually eradicating lag, Ogawa claimed. The system also allows the fitment of a larger turbocharger, making more power available.
“We want to do away with the turbo lag,” he said. “When the customer presses the accelerator the car responds straight away… When you have got that turbo response… we don’t have to make the turbo smaller, which means we can gain the maximum output.”
Response is also aided by repositioning the oil control valve for the VVTi intake and tucking the air-to-water intercooler in close to the engine.
Ogawa explained the integrated cylinder had been successfully achieved because Toyota had been able to resolve issues with water jacket design generated by turbocharger temperatures beyond 900 degrees C.
Separately, Toyota deputy chief officer Satoshi Ogiso, who is best known as the father of the Prius petrol-electric hybrid, said the turbo-petrol engine would be suitable for performance hybrid drivetrains.
“Adding a turbo engine to the hybrid system does not make so much sense for a regular car,” he told motoring.com.au. “But a premium brand or sportier car requires so much performance, so turbocharged hybrid is good for the top-end premium car or sportier car.”
Read the latest news and reviews on your mobile, iPhone or PDA at carsales' mobile site...
Don't forget to register to comment on this article.