A Cold Start Scheme for Methanol Fueled Engines
Melissa G.Pike

 


     Abstract: Replacing gasoline fueled engines with methanol fueled engines has begun in areas with chronic air pollution. Unfortunately, methanol’s low air-fuel ratio, low vapor pressure and high latent heat of evaporation result in cold starting problems. It was the objective of this study to develop a system that would permit a methanol fueled (M100) engine to start at –200F within 15 seconds after the initial cranking.

     The cold start strategy investigated in this study uses a burner operating with a rich methanol air diffusion flame to dissociate methanol into hydrogen (H2) and carbon monoxide. (CO) The products of the fuel-rich combustion are used as fuel to start the engine. Exhaust analysis of the burner designed in this study show it contained 17.6% H2 and 14.2% CO by volume.

     The results of five cold tests showed that it is possible to start a methanol fueled engine at or below –200F. Continuous idle was sustained in 35seconds after the initiation of cranking.

     The basic problem is that at low temperature, the vapor pressure of methanol is so low that the air vapor ratio is too high for spark ignition to occur. Attempts to compensate for this by over-fueling can result in spark plug wetting and subsequent plug shorting. Dissociating the methanol into hydrogen and carbon monoxide produces fuels that are not subject to the problems of flame quenching, plug shorting or condensing. This strategy was considered unattractive due to long warm-up period required for the dissociator apparatus. The strategy ultimately used was to produce an almost instantaneous rich methanol/air diffusion flame and dissociate excess methanol fuel with energy produced.

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Point of Contact: David Irick (phone: 865-974-0863, dki@utk.edu)