Emissions from diesel engines have become recently a significant problem due to their positive effecton global-warming. There are strict restrictions on emissions and low-emission diesel enginesnowadays are required to be developed. One of the solution for reduced-emission diesel engines is toutilize exhaust thermal management systems. However; these systems work efficiently mostly attemperatures above 250 oC and for diesel engines, especially at low speed and low load conditions,exhaust gas temperatures are not generally higher than 250 oC. That not only leads to inefficientaftertreatment systems, but also insufficient emission reduction. Variable valve timing (VVT) can beused to achieve those high exhaust gas temperatures by changing the opening and closing timings ofthe intake&exhaust valves at any speed and any load. Therefore, the aim of this study is to try toincrease the turbine exit temperature of a diesel engine above 250 oC at 2.50 bar brake mean effectivepressure (bmep) and 1200 rpm engine speed condition by changing intake valve closing (IVC) timings.Diesel engine system is simulated by using Lotus Engine Simulation (LES) program. The model is thenvalidated with experimental results. It is seen that exhaust gas temperatures can be raised higher than250 oC for the studied particular engine loading case when IVC is advanced or retarded. The methodresults in fuel consumption saving in comparison to nominal valve timing by decreasing the requiredfuel injection rate for the constant engine loading. However, earlier and later closing of intake valvealso causes exhaust flow rate to drop off.