A research of the effects of intake and exhaust throttling valves on exhaust temperature was carried out on an engine test bench. The results show that in the steady state

the intake throttling valve is better than the exhaust one in terms of raising exhaust temperature

making the temperature rise by up to46 ℃

while the exhaust one by only 25 ℃. In the emission cycle process

both the intake and exhaust throttling valves have a little influence on NOxemissions; the intake throttling valve makes higher rise in the temperature and slightly lower fuel consumption than the exhaust one does; the intake throttling valve can help achieve increase in average exhaust temperature by up to 60 ℃ while the exhaust one by only 28 ℃.