Search Results

The knock sensor is provided on an engine cylinder block to detect abnormal engine combustion (knocking) and to provide feedback to engine control unit (ECU). The ECU then modifies the engine input and avoids knocking. A commonly used knock sensor is an accelerometer that detects cylinder wall vibration and estimates knocking of the engine. Selecting the location of a knock sensor in many cases involves a challenging trial and error approach that depends upon the measurement of the knock signal at many locations on engine structure. However, a cylinder block exhibits many structural resonances. Thus, a large vibration signal at the surface of cylinder block can be either due to knocking of the engine or due to the resonances of the cylinder block structure because of normal excitation forces. Hence, this conventional method does not always yield reliable results.

We present the results from the 3-D numerical simulations on the optimization of the fan-cooling system in a two-wheeler 4-stroke single cylinder engine. Objective was to optimize the flow rate and distribution of flow over the engine surfaces to keep the maximum temperature of engine oil and engine surfaces well within the lubrication and material limit respectively at the expense of minimum increase in fan power. This work aimed at reducing the engine oil temperature by 20°C. Combined flow and heat transfer analysis (Conjugate analysis) was conducted with the engine head and block modeled as solid medium and fan cooling system modeled as fluid medium. Reynolds-Averaged-Navier-Stokes turbulence (RANS) equations along with energy equation were solved to get the flow field and temperature distributions inside the cooling system and on the engine surfaces respectively. Moving Reference Frame approach was used for simulating the rotation of fan.