Improving the environmental performance of the internal combustion engine by the use of in-cylinder catalyst

Monika Andrych-Zalewska

doi:10.19206/ce-2017-120

Abstract

The problems of using the inner surfaces of a combustion chamber as catalytic converters in order to reduce the harmful exhaust emissions were discussed in this paper. The proper choice of the catalyst is one of the most important issues. The interaction between the burned mixture and the catalyst is not limited by the kinetics of the chemical reactions but depends primarily on the flow rate of the reactants to the catalyst surface during combustion. The lifespan of a catalytic layer is determined by the application technique, where plasma spraying is the most popular and most accessible method. However, when it comes to the catalytic coating durability, it is not an efficient option, as ion implantation is indicated shows greater potential in this respect. In this research the coating of aluminum titanium and chromium-nickel have been applied to the engine head and the piston crown. Then the modified catalytic parts were used in a CI combustion engine and the obtained emission results were compared with the reference results. Another set of tests was performed for an SI engine, powered with gasoline and methane, where the piston crown was covered with a thermal layer of zirconium oxide and a catalytic layer of platinum. The beneficial effects of these in-cylinder catalysts on exhaust emissions and the possible problems in the wide spread use of such solutions have been presented.

Highlights

Reciprocating internal combustion engines are a common source of power in the drives of motor vehicles, machinery and equipment
For an internal combustion engine, the nature of its operation determines the formation of harmful exhaust gases, where the proper execution of the combustion process tends to be the primary source of these pollutants
Based on such analysis it can be concluded that the improvement of environmental and economic operating parameters of combustion engines mainly depend on the proper execution of the combustion process, which is highly dependent on the activation energy and the presence of a catalyst that increases the chemical reaction rate

Summary

Introduction

Reciprocating internal combustion engines are a common source of power in the drives of motor vehicles, machinery and equipment. The pursuit to get more and more engine power output, improved work indicators, to reduce the engine weight and its harmful effects on the environment are just some of the targets for engines today All of these aspects substantially affect the engine development process, including its individual components and subsystems. Increasing emphasis on reducing the negative impact of combustion engine vehicles on the environment, both from the legislative institutions of individual countries as well as their communities, drives the search for ever more sophisticated technical solutions for the internal combustion engine, which will ensure environmental impact reduction and allow meeting current emission standards. Careful consideration should be given to measures which are technically feasible and which would influence the reduction of pollutant production at their source – that is, in the combustion chamber of the engine – by adding catalysts as close to the combustion process as possible

The concept of using an in-cylinder catalyst

Possible applications overview

Findings

Conclusions