Start and stop control method and device for internal combustion engine of hybrid vehicle

An internal combustion engine (2) for power generation of a series hybrid vehicle is started when a catalyst temperature and a cooling water temperature drop to an active temperature (TC1) or a lower limit water temperature (TW1), and is stopped when an operation end temperature (TC2, TW2) is reached. A target EV mode operation duration (Tev) is set in advance, an operation end temperature (TC2) is set so that a temperature difference ([delta] TC) with respect to an active temperature (TC1) reaches "[delta] TC = Ra * Tev", and an operation end temperature (TW2) is set so that a temperature difference ([delta] TW) with respect to a lower limit water temperature (TW1) reaches "[delta] TW = Rb * Tev", using respective temperature reduction rates (Ra, Rb). 串联混合动力车辆的发电用的内燃机(2)，如果催化剂温度、冷却水温降低至活性温度(TC1)或下限水温(TW1)则启动，如果达到运转结束温度(TC2、TW2)则停止。预先设定作为目标的EV模式运转的持续时间(Tev)，利用各自的温度降低率(Ra、Rb)，将运转结束温度(TC2)设定为使得与活性温度(TC1)的温差(ΔTC)达到"ΔTC＝Ra×Tev"，将运转结束温度(TW2)设定为使得与下限水温(TW1)的温差(ΔTW)达到"ΔTW＝Rb×Tev"。