Blackburn Cycle Engine

'Blackburn Cycle' Test Results

1,000 tests have been run on a research engine based on a modified Tecumseh HH 100 engine. This engine can change from the usual 4 stroke Otto cycle to the 'Blackburn Cycle' instantly without stopping. Direct comparison is easily made with identical load, speed and all other factors to give a true comparison.

The results below are in seconds of average running times using the same accurate measure of 20 ml of unleaded petrol. Higher powers are not shown because the 'Blackburn Cycle' changes to the 4 stroke cycle for high powers when the fuel efficiency is similar to a usual 4 stroke.

The % gain in seconds of running time below should give the same % gain in miles per gallon on the road. If drivers usually limit acceleration to half power, a 50% reduction in CO2 emissions and fuel use should be achieved. The full power is instantly available if required. This research engine would not run steadily below 1,500 rpm, but a 3 cylinder 'Blackburn Cycle' engine idling at 700 rpm might need only 1/3 of the fuel needed by a 4 stroke at idling.

Revs per minute1,5001,5002,0002,500
Load % of 4 stroke maximum0112650
BC running time seconds325233127106
4 stroke running time seconds16912310065
BC gain seconds1561102741
% gain (BC-4st/4st)92%89%27%65%

Videos of the above and other tests can be attached to emails if requested from

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