The experiments were performed on a four cylinder TOYOTA 2KD-FTV common rail fuel injection diesel engine in the engine laboratory of National University of Singapore [37]. The engine was loaded with an AVL DP 160 water-cooled passive eddy current dynamometer which is able to provide a peak brake power of 160 kW and a maximum torque of 400 N-m with an accuracy of ±0.3%. The air flow rate was measured using an AVL Sensyflow P air flow meter with a resolution of 100 ms for sampling frequency. An AVL 733S.18 fuel balance was used to measure the fuel consumption rate with a sampling frequency of 500 ms and an accuracy of ±1%. The cylinder pressure was measured at a resolution of 1 CAD by an AVL GH13P water-cooled pressure transducer which was mounted on the cylinder head, and it can sustain a peak pressure of 250 bar. Specifications of the engine were given in Table 2 and schematic engine setup was shown in Fig. 2. All the performance parameters are averaged over 50 engine cycles. Heat release rate is one of the most important parameters used to justify the combustion characteristics of a fuel, and it further influences the overall engine performance and emission characteristics. In the present study, the heat release rate is calculated based on the experimental cylinder pressure curve by applying the first law of thermodynamics as shown in Eq. (22) and it does not take into account the heat loss through the cylinder walls.