Cold start characteristics

This chapter describes PEFC cold-start characteristics and performance, focusing on water management and electrochemical kinetics at subzero temperatures. Other issues related to low... 

The cold crank simulator test, ASTM D2602/IP 383, measures the apparent viscosity of an oil sample at low temperatures and high shear rates, related to the cold starting characteristics of engine oils, which should be as low as possible. The oil sample fills the space between the rotor and the stator of an electric motor, and when the equipment has been cooled to the test temperature, the motor is started. The increased viscosity of the oil will reduce the speed of rotation of the motor and indicates the apparent viscosity of the oil. The test is comparative for different oil samples rather than an accurate prediction of the absolute performance of an oil in a specific engine. 

Tabe, Y, M. Saito, K. Kukui, and T. Chikahisa. 2012. Cold start characteristics and freezing mechanism dependence on start-up temperature in a polymer electrolyte membrane fuel cell.. Power Sources 208 366-373. 

Characteristically, PEM fuel cells are less affected by deterioration at sub-zero temperature operations than ordinary batteries, however, the low-temperature startability issues with PEM fuel cells remain an obstacle for the use of PEM fuel cells in cold areas. Freezing of the water produced by the cathode reaction may induce shutdowns during cold starts in sub-zero temperatures. This section introduces results of an investigation of the cold start characteristics of PEM fuel cells. 

Cold start characteristics and the effect of the start-up temperature... 

In this section we shall discuss the development of a global kinetic model for DOC. The basic model reactions considered in the DOC model are summarized in Table II. Here the real HC mixture is modeled by two characteristic hydrocarbons—propene and decane. Propene represents more reactive, light hydrocarbons, which practically do not adsorb during cold start, while decane is a representative of heavier hydrocarbons with significant adsorption on... 

This chapter explains what alternative fuels are and why they are being considered for use in transportation vehicles. The production processes to make each are presented along with examples of recent production volumes. The typical impacts on vehicle performance (power, driveability, cold-start capability, etc.) are presented as well as typical vehicle emissions characteristics. 

Very few heavy-duty propane vehicles have been developed and put into use therefore, a database of knowledge about their performance characteristics does not exist. However, their characteristics should be similar to the relative differences between natural gas heavy-duty vehicles and their diesel engine counterparts. If this supposition holds true, heavy-duty propane vehicles should have similar or better power, the same or better driveability, and better cold-start performance compared to the same vehicle with a diesel engine. (Unlike light-duty vehicles, heavy-duty propane vehicles should have better cold-start performance compared to diesel engines because of the many cold-start challenges diesel engines face.)... 

TPA characteristics of two adsorbers of honeycomb type for various hydrocarbons were evaluated. In this study, methyl alcohol, acetone, acetaldehyde, 224 trimethylpentane, n-octane and toluene were chosen as the hydrocarbons of cold start. The effect of the hydrocarbon components and oxygen concentration on TPA behavior was studied. According to the precious metal loading and the presence of Ch, the adsorption and desotptioit amount were decreased, while the conversion efficiency of hydrocarbons was increased. In case of hydrocarbons with oxygen, the thermal decomposition appeared to be in the order of methanol, acetaldehyde and acetone. 

Methanol faced two major problems Pure or "neat" methanol had physical characteristics that make its use in motor vehicles problematic. Its very low volatility made it difficult to start the vehicle at low temperatures, and its nearly invisible flame raised safety concerns in the event of a collision or other spillage. These problems were solved by blending 15 percent gasoline into neat methanol to produce M85, which had sufficient volatility for cold starts and burned with a pronounced gasoline-like orange flame. 

Better low- and high-temperature viscosity characteristics Better cold starts Less evaporative loss Greater life... 

P-32 - Adsorption characteristics on zeolite catalysts for hydrocarbon removal under cold-start engine condition... 

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