Effect of manifold injection of methanol/n-pentanol in safflower biodiesel fuelled CI engine

This paper intends to study the influence of methanol and n-pentanol pre-injection in the inlet manifold with safflower oil biodiesel (B100) as base fuel replacing diesel. Safflower oil biodiesel was prepared through the transesterification process. Experiments were conducted in a single cylinder CI engine with the test fuels to evaluate the performance, emission and combustion parameters. Methanol and n-pentanol were injected in the inlet manifold along with intake air which enters the combustion chamber during the intake stroke. Both methanol and n-pentanol were injected 10% and 30% on a mass basis along with B100. The results demonstrated that the brake thermal efficiency in comparison to neat biodiesel operation is higher with methanol and n-pentanol injection. On 10% mass basis, the efficiency is higher with n-pentanol engine operation than methanol whereas the trend is opposite when 30% mass percentage of alcohols is used, due to higher heat release with methanol since its latent heat of vaporization is highest. The HC, CO and NOx emissions were higher with alcohol injection. Whereas the smoke emissions reduced with alcohol injection. The reduction in smoke emissions is due to homogeneous mixture formation between the pre-injected alcohols and air and less amount of biodiesel injected in this mixture. The increase in the mass percentage of alcohol tends to lower the smoke emissions further.