Cylinder Block Temperature Mapping and Development of Cooling Cowl for Reducing the Maximum Liner Temperature 2012-01-0405

To improve the performance and durability of two-stroke engines, temperature of the liner/block is an important parameter, which needs to be optimized. In this paper, an attempt is made to measure and investigate the maximum liner temperature of a forced-air-cooled two-stroke engine.

The vehicle was tested on both chassis dynamometer and test track to identify the maximum liner temperature during operating conditions. Thermocouple locations were selected at or near the hot spots (TDC & Exhaust port) in the cylinder block. The chassis dynamometer test revealed that the maximum liner temperatures for the test vehicle were near the exhaust port reference position (34 mm from the top face of cylinder block) and TDC reference position (8 mm from the top face of cylinder block near the exhaust port). The Computational Fluid Dynamics (CFD) simulation was used to study the flow pattern around the block and the results revealed that design modifications can be done on the base cowl to improve and optimize the cylinder block liner temperature. Hence, the base cowl was experimentally modified using prototype cowls and was tested on chassis dynamometer to verify the temperature reduction.

The target of reducing the maximum liner temperature for the test engine below the critical value (240°C) was achieved using the finalized experimental prototype cowl. Confirmation trials on the test track for the finalized prototype cowl demonstrated that there was a temperature reduction of 9% at exhaust reference position and 5% at TDC reference position.