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This paper presents the progress of an ongoing vehicle micro corrosion environment study. The goal of the study is to develop an improved method for estimating vehicle corrosion based on the Total Vehicle Accelerated Corrosion Test at the Arizona Proving Ground (APG). Although the APG test greatly accelerates vehicle corrosion compared to the field, the “acceleration factor” varies considerably from site-to-site around the vehicle. This method accounts for the difference in corrosivity of various local corrosion environments from site-to-site at APG and in the field. Correlations of vehicle microenvironments with the macroenvironment (weather) and the occurrence of various environmental conditions at microenvironments are essential to the study. A comparison of results from APG versus field measurements generated using a cold rolled steel based corrosion sensor is presented.

Automotive corrosion is a complex issue since a vehicle is comprised of many materials and different locations on the vehicle experience different corrosion environments. As a result, multiple corrosion mechanisms are encountered. Hence, development of an accelerated corrosion test for automobiles that correlates well to real world corrosion situations is a challenging task. Most corrosion tests currently used in the automotive industry were designed for corrosion of steel. With an increasing use of aluminum and magnesium alloys, galvanic corrosion becomes a critical issue. Applying corrosion tests designed for steel to evaluate galvanic corrosion of lightweight alloys could lead to erroneous conclusions since the acceleration factors for the two corrosion mechanisms may be very different.

This paper presents the progress of an ongoing corrosion study of vehicle microenvironments. The study identifies the difference of corrosion microenvironments at various automotive proving grounds, using a sensor-equipped vehicle. A vehicle was instrumented for the proving ground test study. Various types of environmental sensors were installed at more than thirty-five sites on the vehicle. These sensors measured the temperature and relative humidity of the ambient air, and the temperature and time-of-wetness of the sites' surfaces. Cold rolled steel (CRS) and Zinc (Zn) corrosion rate sensors were also used in the experiments. The comparative analysis of vehicle microenvironments and corrosion rates of CRS and Zn, from three corrosion proving ground tests, will be discussed.

An obliquely incident X-ray radiography was developed to measure the greatest depths, orientations and locations of corrosion pits in automobile metallic plates. This technique can also be used on-site for components in use. The corrosion depth profile and the greatest depth can be calculated with the established relations. A 3-D rotational microscope and surface profiler were utilized to evaluate the sensitivities and accuracies of the technique for aluminum and steel plates, respectively.

Vehicle hydraulic retarders are applied in heavy-duty trucks and buses as an auxiliary braking device. In traditional cooling systems of hydraulic retarders, the working fluid is introduced into the heat exchanger to transfer heat to the cooling liquid in circulation, whose heat is then dissipated by the engine cooling system. This prevents the waste heat of the working fluid from being used effectively. In hydraulic retarder cooling system based on the Organic Rankine Cycle, the organic working fluid first transfers heat with the hydraulic retarder working fluid in Rankine cycle, and then outputs power through expansion machine. It can both reduce heat load of the engine cooling system, and enhance thermal stability of the hydraulic retarder while recovering and utilizing braking energy. First of all, according to the target vehicle model, hydraulic retarder cooling system model based on Rankine cycle is established.

The hydraulic retarder is an auxiliary braking device used for commercial vehicle in a long slope brake, and its transmission oil generates a lot of heat in its working process. If the heat of transmission doesn’t go through a reasonable management, it will seriously affect the braking performance of hydraulic retarder. To cool down the transmission oil, it will aggravates the load of the engine cooling system, and the long cooling path sometimes causes heat exchange not timely. When the Rankine cycle is used for cooling the hydraulic retarder transmission oil in virtue of its good heat transfer performance in phase change process, it can make the transmission oil temperature controlled more stable. In this new system, the setting parameters of the Evaporate-condensate system will affect the stability of the transmission oil temperature in the hydraulic retarder inlet and the energy recovery efficiency of the system.

The F-T diesel made from coal by Fischer-Tropsch synthesis (F-T) can be used as a clean alternative fuel of diesel engine. To alleviate the drawback of high cost and low viscosity of F-T diesel, the Methanol-Biodiesel -F-T diesel multiple fuel (MBFT) was prepared by adding low-cost methanol and high-viscosity biodiesel as modifiers. Considering the immiscibility between alcohols and hydrocarbons, this paper carried out a series of stability tests and found that n-decanol was the optimum co-solvent of MBFT. The MBFTs blended by biodiesel with the volume fraction of 10% (10% vol.) and methanol with varying proportions of 0%, 5%, 10% and 15% vol. were denoted as M0, M5, M10 and M15, respectively. The increasing methanol proportion caused the increase of the oxygen content in the blended fuels and the reduction of heat value, surface tension and cetane number. The influence of methanol proportion on combustion characteristics of turbo-charging engine was studied.

As the explosion proof diesel engine (EPD) of underground trackless tyred vehicle dynamic mechanical device, due to its good dynamic and economic performance, the diesel has been widely applied. The flame arrester can prevent the exhaust system from tempering, but the increased resistance will seriously affect the performance of diesel. Through the comparison of the CFD-FLUENT fluid simulation on flow and pressure field, the results show that the corrugated flame arrester performs better on reducing the exhaust back pressure than flat flame arrester and ensures the explosion-proof effect. The bench test of explosion proof diesel engine on intake and exhaust system is conducted, analysing the effect of the exhaust resistance under different speeds of diesel engine on the power, economy and emission of TY4100QFB type diesel engines with equivalent flow area , different specifications of flat versus corrugated flame-arrester in the course of external characteristics.

Two passenger cars have been instrumented for a comparative study of vehicle micro environments (data gathered from onboard vehicle sensors) and the macro environment (data gathered from a Detroit metro area weather station). Environmental sensors were installed at more than thirty corrosion prone sites on each of the two vehicles to measure temperature and relative humidity of the air and temperature and time-of-wetness of the surface. The weather station data include temperature, relative humidity, and daily rainfall. Data collected over a one year period are analyzed and the results are presented. The results indicate that the micro environment (or “environmental corrosion load”) varies considerably from site to site around the vehicles. These vehicles will continue to gather data for another year. They will then be sent through several cycles of a total vehicle corrosion test at an automotive proving ground. The micro environment response during the test will also be recorded.

The Organic Rankine Cycle System (ORC) is an effective means to use the solar energy. The system adopts the solar energy on the car roof as the heat source to make the ORC work and drive the thermoelectric air-conditioner. It can improve the entering comfort on the parking condition and the vehicle energy utilization efficiency. In this research, the system comprehensively applied the principle of sunshine concentration, heat collection and photo electricity. Then considering the working condition and performance features of ORC system, the car roof was designed to have a compact structure, through which the efficiency of the solar vehicle system could be improved. Firstly, the research analyzed the heat source temperature and the heat flux impact on the output power of the ORC system. After that, the performance of heat collection was identified according to the given thermoelectric air-condition’s power requirements.