Heavy-duty Application Research Articles

An adsorption air conditioning system to integrate with the recent development of emission control for heavy-duty vehicles

The recent development to control the emissions of large diesel engines has provided opportunities for heat-driven cooling methods in vehicles. An adsorption air conditioning system is therefore proposed in this work for heavy-duty truck application. This system is powered by engine waste heat when the engine of a truck is running. When the engine is off, it can be operated by fuel fired heaters, a newly implemented technology to reduce truck idling. Hence, this system can not only reduce engine emissions but also improve the overall energy efficiency. A lumped parameter model of the system using zeolite-water as its working pair is developed, and the adsorption capacity of zeolite is simulated with the linear driving force model. The dynamic performance of the system and a parametric study on adsorbent mass transfer, operating temperatures and cycle operating periods are presented. Alternative working pairs and the potential to commercialize the system are also discussed. This system may be designed to satisfy the cooling requirement for idle reduction of long-haul trucks.

4 L Light Duty LPG Engine Evaluated for Heavy Duty Application

4 L Light Duty LPG Engine Evaluated for Heavy Duty Application

2D simulation of the regeneration performance of a catalysed DPF for heavy-duty applications

The objective of this work is to study the regeneration performance of a heavy-duty DPF application. The simulation of the local temperatures and pressure drop during the regeneration could be validated with experimental data, indicating the need for a 2D model approach to describe this particular catalysed DPF configuration. Furthermore, the model was applied to illustrate the axial and radial regeneration phenomena focusing on soot and temperature distribution.

Control of an SCR catalytic converter system for a mobile heavy-duty application

Selective catalytic reduction (SCR) is well known for exhaust gas aftertreatment in power plant applications. In the near future, it will be introduced in Europe in mobile heavy-duty diesel applications. Stringent specifications and the dynamic operation mode of such applications demand advanced control strategies. Such a control strategy is presented here. It incorporates a model-based feedforward controller (FFC) which handles the known dynamics of the plant. It further contains a feedback controller (FBC) to compensate for disturbances and slowly varying parameters. The realization of the feedback control loop is possible only due to the use of a nitrogen oxide (NO/sub x/) sensor which is cross-sensitive against ammonia (NH/sub 3/), and the implementation of a procedure separating the detection of NO/sub x/ and NH/sub 3/.

Modeling and Control of an SCR System

This paper presents a mean-value model describing the selective catalytic reduction (SCR) system of a mobile heavy duty application. The system consists of a single coated honeycomb-type catalytic converter for the SCR of NOx. The model of the catalytic converter system is zero-dimensional. Its core consists of two identical cells that describe the thermal and the chemical behavior of the SCR converter. The model is used to design model-based feedforward controllers and to explore the system's performance, specially its trade-off between NOx removal rate and secondary NH3 emission. The results are validated by experiments on the dynamo meter.

Application of NOx Adsorber to Diesel Depollution: Performances and Durability

To ensure overall optimization of engine performance (NOx, particulates, efficiency), the use of a NOx after-treatment system appears necessary to meet the future Euro IV emissions standards and after. Among the known means, the NOx trap should offer an efficiency of the same order than the reduction by urea, without having the same constraints. The trap operates on the basis of the alternation of operating phases with a lean mixture during which NOx is stored and rich phases during which nitrates are destored and treated. Important aspect of the technology, NOx adsorbers are very sensitive to sulfur poisoning and future fuel standards are unlikely to be sufficient to prevent the system from requiring periodic desulfation procedures. The present paper presents results obtained on a light duty application, on a one hand, on a heavy duty case on a second hand. In the light duty front, the purpose of the work presented first, was to study the effects of low fuel sulfur content such as 50 ppm and 10 ppm on the NOx adsorber efficiency for a Diesel application. Through this study, the influence of the substrate cell geometry has also been assessed. The use of a 10 ppm sulfur fuel is not enough to maintain, at a high level, the NOx adsorber performance during a 40 000 km aging test. The desulfation criterion (efficiency loss of 30%) is reached after the first 16 000 km. However, the desulfation operation is not enough to recover the initial catalyst performance and the poisoning velocity increases as the catalyst ages. The hexagonal cell substrate catalyst is less sensitive to sulfur poisoning than a square cell substrate catalyst so that its desulfation frequency is much lower. With a 10 ppm sulfur fuel, 4 desulfation operations were achieved with a hexagonal cell catalyst as opposed to 11 with a square cell catalyst during the 40 000 km aging test. In the heavy duty application, the investigation, using a single-cylinder engine, demonstrated that the best NOx emission/fuel consumption trade-off are obtained with destorage richer than stoichiometry. These destorage conditions could be obtained in various configurations (injection timing, EGR, post-injection). The various adjustments tested show the advantage of producing a large amount of carbon monoxide to obtain fast destorage and efficient treatment of the trapped nitrates. With a method like this, the extra fuel consumption resulting from the succession of rich/lean phases is around 3% for an emission objective of NOx < 3. 5 g/kW·h. By mounting a second trap in parallel, an oxidation catalyst, or using EGR, this result can be significantly improved. The gradual storage of sulfur contained in fuel limits the trapping capacity of the NOx system, necessitating periodic desulfation. Various configurations have been tested to purge the sulfates. Mass spectrometer exhaust gas analysis makes it possible to quantify COS, H2S and SO2 emissions during this phase. Nevertheless, the tests have shown the limits of the possibilities in a single cylinder installation.

The High-Speed Heavy-Duty Diesel Engine, Its Development, Design and Application

The High-Speed Heavy-Duty Diesel Engine, Its Development, Design and Application

Centrifugally Cast Bronze-Back Bearings for Heavy-Duty Operation

Abstract The art of centrifugally casting bronze-backed bearings for use in heavy-duty Diesel engines is only 4 to 5 years old and was introduced by the United States Navy at the end of the last war. Steel-backed bearing material will withstand any actually applied loads in operation without permanent deformation, because of adequate physical properties. However, sand-cast bronze-backed bearings did not operate satisfactorily when subjected to high cyclic loads. The introduction of centrifugally cast bronze for that purpose made it possible to use successfully bronze-backed bearings for heavy-duty application. This paper describes the performance and the salient points of manufacture of centrifugally cast bronze-backed bearings. Comparison of the sand-cast and of centrifugally cast bronzes are discussed and the advantages of the latter are mentioned. Methods of rational casting of bearing-back-bronze material are also discussed in detail and steps for the improvement of their physical properties are indicated.