Search Results

The emission characteristics of compression ignition (CI) engines running on biodiesel during transient operating conditions, which is the most usual case in urban and extra-urban transportation, have rarely been investigated. In the present study an experimental investigation on emission characteristics of a CI engine has been carried out both under steady state and transient operating conditions. The experimental work has been carried out on CI engine, which is integrated with transient testing facility. This facility is capable of varying the engine speed and load over a given time period. To measure the engine emissions, an emission analyzer has been used to measure CO₂, CO, THC, and NOx emissions. The fuels used in the analyses are 25% (25B) and 100% (100B) of biodiesel blend and diesel. The series of the transient events studied are speed changes from 900 to 1200rpm, 1200 to 1500rpm and 1500 to 1800rpm over a time period of 4 seconds each.

Growing global concern pertaining to climate change has meant that engine development has become more focused on engine emissions. A method of reducing the emissions of an internal combustion (IC) engine is to use smaller engines but recover power lost due to reduction in size by using a turbocharger or supercharger. Turbocharged vehicles are commonly used but they exhibit a weak point of poor performance under transient running conditions. The phenomenon, known as “Turbo-lag”, is most noticeable when a sudden load change is applied at lower engine speeds combined with rapid acceleration. The work presented analyses a novel method of improving the transient performance of turbocharged engines by injecting air into both the compressor of the turbocharger as well as inlet manifold of the engine-known as a two point air injection system.

Within this paper the convective heat dissipation from the front brake discs fitted to the left and right hand side of a high performance passenger car has been compared. The tools used in this investigation include computational fluid dynamics (CFD) and vehicle testing. The results show that although identical discs are fitted to both sides of the vehicle the disc fitted to the left hand side shows better thermo-aerodynamic properties than that fitted to the right due to the different direction of rotation. The computational model shows strong agreement with the test results; over predicting the average heat transfer coefficient by 4% for the left hand disc and 7.6% for the right disc. The CFD analysis enabled a detailed insight into the air flow and heat transfer distributions that was not possible during the vehicle test regime.