Search results for " Spark ignition engines"
showing 3 items of 3 documents
A Study on the Use of Combustion Phase Indicators for MBT Spark Timing on a Bi-Fuel Engine
2007
The performance of a spark ignition engine strongly depends on the phase of the combustion process with respect to piston motion, and hence on the spark advance; this fundamental parameter is actually controlled in open-loop by means of maps drawn up on the test bench and stored in the Electronic Control Unit (ECU). Bi-fuel engines (e.g. running either on gasoline or on natural gas) require a double mapping process in order to obtain a spark timing map for each of the fuels. This map based open-loop control however does not assure to run the engine always with the best spark timing, which can be influenced by many factors, like ambient condition of pressure, temperature and humidity, fuel p…
Performance Prevision of a Turbocharged Natural Gas Fuelled S.I. Engine
2008
Natural gas represents today maybe the most valid alternative to conventional fuels for road vehicles propulsion. The main constituent of natural gas, methane, is characterized by a high autoignition temperature, which makes the fuel highly resistant to knocking: this allows a considerable downsizing of the engine by means of supercharging even under high compression ratio. Starting from these considerations, the authors realized a thermodynamic model of a 4-cilynder s.i. engine for the prevision of in-cylinder pressure, employing a two-zone approach for the combustion and adding sub-models to account for gas properties change and knocking occurrence. An extensive experimental campaign has …
The Experimental Validation of a New Thermodynamic Method for TDC Determination
2007
In-cylinder pressure analysis is becoming more and more important both for research and development purpose and for control and diagnosis of internal combustion engines; directly measured by means of a combustion chamber pressure transducers or evaluated by analysing instantaneous engine speed [1,2,3,4], incylinder pressure allows the evaluation of indicated mean effective pressure (IMEP), combustion heat release, combustion phase, friction pressure, etc...It is well known to internal combustion engine researchers that for a right evaluation of these quantities the exact determination of Top Dead Centre (TDC) is of vital importance: a 1° error on TDC determination can lead to evaluation err…