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Heavy-duty axle and manual transmission lubricants formulated with Group II base oil and borate additive chemistry were tested in a 250,000-mile, extended-drain, on-highway field test. For reference, units using a synthetic sulfur-phosphorus axle lubricant and a synthetic engine oil type transmission fluid were monitored. The field test involved two major fleets with approximately 200 trucks. Twenty axles and transmissions using the Group II borate chemistry lubricants were inspected as they reached greater than 275,000 miles. Oil analysis was performed on the units running on the test and reference lubricants. Test data indicated that all four lubricants performed well. However, end-of-test oil analysis data showed significantly less wear with the Group II products formulated with borate chemistry compared to the reference products. In the axle test, the iron wear rate for the Group II borate chemistry lubricant was 56% lower than the iron wear rate for the synthetic axle lubricant.

This paper describes the results of a comprehensive field-testing program conducted in modern low-emission heavy-duty diesel engines to evaluate the extended oil drain capabilities of several diesel engine oils of varying performance levels. The data generated in the 59-truck trial, which was conducted over a two to three year period, provide support for extension of engine oil drain intervals when a premium mineral diesel oil is used rather than a fighting-grade mineral diesel product. The field trial results also document the performance of a premium fully synthetic engine oil at four times conventional oil drain intervals. Engine inspections conducted after 500,000 test miles confirm that the extension of oil drain intervals with premium diesel engine oils has no negative impact on engine durability.

The importance of the fuel in providing improved vehicle performance and reduced emissions has become widely recognized in the past ten years. However, few if any systematic analyses of gasoline quality have ever been published. A methodology has been developed for analyzing the vehicle performance and emissions characteristics of gasolines. It has been applied to data obtained from surveys of United States' service station gasoline samples obtained in 23 cities during 1996. Results are presented for: gasoline type (California RFG - reformulated gasoline, Federal RFG, low RVP - Reid Vapor Pressure, and conventional); gasoline grade (regular, intermediate and premium); individual cities; individual brands (coded); and for sulfur content, the fuel property with the greatest current interest. It is concluded that large differences exist among commercial gasolines for all of the items evaluated.

In vehicles equipped with knock sensors, it can be difficult to determine the octane number requirement according to the current Coordinating Research Council E-15 procedure which is based on detection of audible knock by trained raters. Therefore, a program was conducted to develop a new procedure which is more suitable for knock sensor equipped vehicles. Due to adaptive actions taken by the electronic knock control system, the acceleration performance of a knock sensor equipped vehicle can be affected by fuel octane number. For the majority of vehicles tested, the acceleration time increased as fuel octane number was decreased. A promising new method was developed to determine vehicle octane number requirement based on acceleration performance.

A model has been developed to predict quantitatively the results of the ASTM D86 fuel distillation procedure. The model uses material and energy balances to treat the procedure as a two stage unsteady-state distillation coupled with an air-filled continuous stirred-tank reactor (CSTR). Heat is removed from the second stage to simulate convection losses from the experimental apparatus. The model requires as inputs the fuel composition and the physical properties of all components (vapor phase heat capacity, vapor pressure, critical properties, density, molecular weight, solubility parameter). Correlations were used to approximate other needed properties. Liquid-phase activity coefficients were calculated with the UNIFAC model. Heat losses were modeled with a correlation from the literature. The model was validated by comparing predictions to experimental measurements on a seven-component model fuel. Agreement was extremely good across the entire range of volume fractions distilled.

It is desirable to predict the cold weather driveability performance of fuels by means of an index based on simple measurements such as the ASTM distillation curve. In the past, several such indices have been proposed from the analysis of vehicle test results. In contrast, this paper describes how a driveability index can be derived from first principles - namely, the physics of fuel vapour formation. A number of present and proposed driveability indices were evaluated by comparing the way they correlate with the calculated enthalpy requirement of fuels. It is concluded that E100+E150 best meets the need for a simple index and is robust across a range of air/fuel ratios.

Certain polycyclic aromatic hydrocarbons (PAH) are carcinogenic and discussion will commence shortly in Europe on the development of an appropriate ambient air quality standard. With this proposed standard in mind, it is important to understand the contribution made by different emission sources to ambient PAH; this paper addresses only the contribution from automotive exhaust emissions. Methods for the sampling and analysis of particulate bound PAH from exhaust emissions, although not standardised, are well established. Vapour phase PAH however, are often neglected and need to be accurately quantified to assess the total contribution made by automotive sources to anthropogenic PAH emissions to the atmosphere. This paper describes the development of a technique applicable to the simultaneous collection and measurement of both vapour phase and particulate bound PAH in exhaust emissions. The final method selection focused on a filter/adsorbent trap sampler.

Traditional approaches to pollution control have been to develop benign non-polluting processes or to abate emissions at the tailpipe or stack before emitting to the atmosphere. A new technology called PremAir®* Catalyst Systems takes a different approach and directly reduces ambient ground level ozone. This technology can be applied to both mobile and stationary applications. For automotive applications, the new system involves placing a catalytic coating on the car's radiator or air conditioner condenser. As air passes over the radiator or condenser, the catalyst converts the ozone into oxygen. Three Volvo vehicles with a catalyst coating on the radiator were tested on the road during the 1997 summer ozone season in southern California to assess performance. Studies were also conducted in Volvo's laboratory to determine the effect of the catalyst coating on the radiator's performance with regard to corrosion, heat transfer and pressure drop.

Fouling spark plugs on an internal combustion engine is greatly influenced by cold temperatures, especially at older assembly plants where the vehicle is moved several times because of discontinuities in the assembly line. To transition the vehicle, the operator starts the vehicle, places it in drive and accelerates rapidly, then shuts the vehicle off. This process only lasts ten to fifteen seconds and does not allow the spark plug or engine to get to a high enough operating temperature to evaporate away the fuel, which fouls the spark plugs. A spark plug fouling test is devised and is used to investigate which properties of fuel play the most significant anti-fouling role. Some additives believed to have anti-fouling properties will also be investigated to determine their significance. The anti-fouling fuel will then be implemented at the assembly plants.

The Coordinating Research Council conducted a program to measure the effect of fuel sulfur on emissions from California Low Emission Vehicles (LEVs). Twelve vehicles, two each from six production LEV models, were tested using low mileage as-received catalysts and catalysts aged to 100k by each vehicle manufacturer using “rapid-aging” procedures. There were seven test fuels: five conventional fuels with sulfur ranging from 30 to 630 ppm, and two California reformulated gasoline (RFG) with sulfur of 30 and 150 ppm. Reducing fuel sulfur produced statistically significant reductions in LEV fleet emissions of NMHC, NOx and CO. Comparing conventional fuel and California RFG at the same sulfur level: California RFG had lower NMHC and NOx emissions and higher CO emissions, but only some NMHC and NOx differences and none of the CO differences between conventional and California RFG were statistically significant.

In the current investigation, the authors identified conditions under which increased in-cylinder turbulence can be used to improve diesel emissions. Two separate regimes of engine operation were identified; one in which combustion was constrained by mixing and one in which it was not. These regimes were dubbed under-mixed and over-mixed, respectively. It was found that increasing mixing in the former regime had a profound effect on soot emission. Fuel injection characteristics were found to be extremely important in determining the point at which mixing became inadequate. In addition, the ratio of the fuel injection momentum flux relative to that of the gas injection was found to be important in determining how increasing mixing would effect soot emissions.

The traditional diesel engine suffers from high emission levels of nitrogen oxide and particulate matter. A new injection concept has therefore been developed and investigated. To enhance the air-fuel mixing process and avoid local concentration of fuel, the injection direction of each spray is varied during the injection event. This was achieved by rotating the injector. In this test, the rotational speed was 1700 rpm. On a six-cylinder engine, one cylinder was equipped with the new injector and exhaust gases were sampled with a new type of valve, integrated in the exhaust-valve stem of the affected cylinder. Tests show that the combustion is significantly affected by the rotating injection. The impact of the rotating injection on smoke, emissions and heat release was repeatable but dependent on loadpoint. No universal trend over all loadpoints was found. NO levels were mostly lowered but for smoke and CO, both lower and higher levels than without rotation were encountered.

This paper describes the combustion optimizations of heavy-duty diesel engines for the anticipated future emissions regulations by means of an electronically controlled common rail injection system. Tests were conducted on a turbocharged and aftercooled (TCA) prototype heavy-duty diesel engine. To improve both NOx-fuel consumption and NOx-PM trade-offs, fuel injection characteristics including injection timing, injection pressure, pilot injection quantity, and injection interval on emissions and engine performances were explored. Then intake swirl ratio and combustion chamber geometry were modified to optimize air-fuel mixing and to emphasize the pilot injection effects. Finally, for further NOx reductions, the potentials of the combined use of EGR and pilot injection were experimentally examined. The results showed that the NOx-fuel consumption trade-off is improved by an optimum swirl ratio and combustion chamber geometry as well as by a new pilot concept.

A variable swirl intake port system for 4 valves/cylinder direct injection diesel engines was developed. This system combines two mutually independent intake ports, one of which is a helical port for generating an ultra-high swirl ratio and the other is a tangential port for generating a low swirl ratio. The tangential port incorporates a swirl control valve that controls the swirl ratio by varying the flow rate. To investigate the performance of the intake port system, steady-state flow tests were conducted in parallel with three-dimensional computations. In conducting the steady-state flow tests, it was found that a paddle wheel flow sensor was not suitable for evaluating the characteristics of the high-swirl port and that it was necessary to use an impulse swirl flow meter.

This paper is a direct continuation of a previous study that addressed the performance and design of a variable compression engine, the Alvar-Cycle Engine [1]. The earlier study was presented at the SAE International Conference and Exposition in Detroit during February 23-26, 1998 as SAE paper 981027. In the present paper test results from a single cylinder prototype are reviewed and compared with a similar conventional engine. Efficiency and emissions are shown as function of speed, load, and compression ratio. The influence of residual gas on knock characteristics is shown. The potential for high power density through heavy supercharging is analyzed.

A single-cylinder direct-injection (DI) Diesel engine (Cummins 903) equipped with a new laboratory-built electronically controlled high injection pressure fuel unit (HIP) was studied in order to evaluate design strategies for achieving a high power density (HPD) compression ignition (CI) engine. In performing the present parametric study of engine response to design changes, the HIP was designed to deliver injection pressures variable to over 210 MPa (30,625psi). Among other parameters investigated for the analysis of the I-IPD DI-CI engine with an HIP were the air/fuel ratio ranging from 18 to 36, and intake air temperature as high as 205°C (400°F). The high temperatures in the latter were considered in order to evaluate combustion reactions expected in an uncooled (or low-heat-rejection) engine for a HPD, which operates without cooling the cylinder. Engine measurements from the study include: indicated mean effective pressure, fuel consumption, and smoke emissions.

Chemiluminescence imaging has been applied to a parametric investigation of diesel autoignition. Time-resolved images of the natural light emission were made in an optically accessible DI diesel engine of the heavy-duty size class using an intensified CCD video camera. Measurements were obtained at a base operating condition, corresponding to a motored TDC temperature and density of 992 K and 16.6 kg/m3, and for TDC temperatures and densities above and below these values. Data were taken with a 42.5 cetane number blend of the diesel reference fuels for all conditions, and measurements were also made with no. 2 diesel fuel (D2) at the base condition. For each condition, temporal sequences of images were acquired from the time of first detectable chemiluminescence up through fully sooting combustion, and the images were analyzed to obtain quantitative measurements of the average emission intensity.

In this paper, the authors proposed a method for on line rapid estimation of power performance and mechanical losses of engines. The power and mechanical losses of an engine are estimated based on the principle of inertia acceleration-deceleration and the measurement of transient crankshaft speed variation that were taken from the updated data acquisition processing measurement system. The calculation, feature and function of the on line rapid estimation methods are described. The derived power and mechanical losses using this method were compared to the results by dynamometer. The experimental equipment as well as the results are illustrated. Using this method, the characteristic mechanical efficiency of the engine as well as the cylinder's relative compression[1][2], starting and acceleration performance could also be estimated easily.

An innovative rotary engine uses a rotor that executes pendulum-like oscillatory rotation. This is converted into uniform rotation of the drive shaft by a simple mechanism. The engine also employs parameter resonance. The new design is compact and lightweight. Economy of fuel and lubricants, reduced air pollution, simpler and cheaper fabrication, lower levels of noise, easier maintenance are among its advantages over the Wankel rotary engine and the Otto piston engine.

A conceptual understanding of modularity in internal combustion engines (defined as design, operation, and sensing on an individual cylinder basis) is presented. Three fundamental modular concepts are identified. These are dissimilar component sizing and operation, component deactivation, and direct sensing. The implementation of these concepts in spark ignition internal combustion engines is presented. Several modular approaches are reviewed with respect to breathing, fueling, power generation, and sensing. These include dissimilar orientation, geometry, and activation of multiple induction runners, partial or total disablement of valves through direct or indirect means, dissimilar fueling of individual cylinders, skipping the combustion event of one or more cylinders, deactivation of dissimilar individual cylinders or a group of cylinders, and individual cylinder gas pressure and mixture strength sensing.