Development of an Ethanol Fueled Version of the Volvo TD73 Diesel Engine.
Konferensbidrag (offentliggjort, men ej förlagsutgivet), 1994
The continually growing demands over the quality of the environment, followed by the progressive legislation aimed at controlling pollutants, have created a need for a further development of the engine design and the exhaust gas after treatment systems as well.
In order to achieve extensive reduction of the pollutants and appropriate engine performance, an optimization of an ethanol fueled version of the Volvo TD73 diesel engine was performed based on a computerized analysis of measured engine parameters.
A back pressure regulator (ATR) is mounted on the turbocharger outlet; therefore the engine was forced to work against a back pressure, particularly at light loads where the emission levels are expected to be undesirable. Hence, by reducing air intake, an increase of cylinder gas temperature was certainly expected and a continuous decline in emissions with increase of back pressure was obtained. Furthermore, the effect of a by-pass valve, installed between intercooler and intake manifold, on emission levels were investigated and optimized.
Oxidation catalysts effects on regulated emissions, especially unburned fuel, carbon monoxide and unregulated emissions such as formaldehyde, acetaldehyde, and acetic acid were investigated. In correlation with the back pressure regulator, a promoting faster catalyst Warm-up was achieved, and their conversion efficiencies were improved.
In order to gain more extensive information to base specification of the engine emissions and catalyst selection, different test cycles such as European R49-13 mode, steady state adoption of the Braunschweig cycle, 24 specific steps cycle, as well as conditioning, activating and transient cycles were used.
As a result it has been found that the performance of ethanol engine version was mentained and the significant emissions, well below the goal, were achieved