Question: what component of the engine determines the stroke
[{'answer': 'type of power cycle used', 'provenance': [{'wikipedia_id': '3142841', 'title': 'Stroke (engine)', 'start_paragraph_id': 3, 'start_character': 16, 'end_paragraph_id': 3, 'end_character': 40, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': "phase of the engine 's cycle"}, {'answer': 'the distance travelled by the piston in each cycle'}]