This is the all-new, BMW 1.5-litre, three-cylinder turbocharged engine. It will find its way under the bonnet of next year’s new Mini, the new front-drive BMW family and, it’s rumoured, today’s rear-drive 1-series and 3-series models. 

Codenamed B38 (petrol) and B37 (diesel), it will come in petrol and diesel forms and is expected to be between five and 15 per cent more economical than BMW’s current N20 four-cylinder engines. 

Built on an alloy block, the engine gets Valvetronic variable valve timing, a single turbo, 11.0:1 compression ratio and a longer stroke than the N20. It has been engineered as part of BMW future modular engine strategy, which sees all engines based on the same individual 500cc cylinder. 

BMW says the petrol engine will develop between 40bhp and 66bhp per cylinder, giving the various versions power outputs of between 120bhp and 200bhp. The torque outputs are expected to be between 44lbft and 66lb ft giving a range of 132lb ft and 198lb ft. 

The B37 diesel engine shares up to 60 per cent of its architecture with the petrol engine and can be made on the same production line. The diesel engine output will range between 100bhp and 181bhp and 166lb ft and 221lb ft of torque. 

The engine is likely to first appear in the rear of the BMW i8 hybrid supercar, where it will be equipped with a generator to help recharge the battery pack. BMW's Hams Hall plant is expected to produce the new engine.

BMW is also preparing the B48, the four-cylinder sister engine of the B38. It is expected to power models including the next-generation Mini Cooper S, to be shown in late 2013. The engine is expected to produce in excess of 220bhp.

Greg Kable/Hilton Holloway