Spencer C. Sorenson

Mean Value Modelling of Spark Ignition Engines

ed and indexed in the SAE Global Mobility Database. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher. ISSN 0148-7191 Copyright 1990 Society of Automotive Engineers, Inc. Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. A process is available by which discussions will be printed with the paper if it is published in SAE Transactions. For permission to publish this paper in full or in part, contact the SAE Publications Group. Persons wishing to submit papers to be considered for presentation or publication through SAE should send the manuscript or a 300 word abstract of a proposed manuscript to: Secretary, Engineering Activity Board, SAE.

The influence of driving patterns on petrol passenger car emissions

An experimental study was performed in which the emissions of fleets of petrol passenger cars with and without catalysts were determined for on-road driving conditions. Measured driving patterns from a wide variety of driving situations in Denmark were driven on a chassis dynamometer for the testing. An analysis of the driving patterns shows a relation between speed fluctuations and the average trip speed driven on the particular road. Emission trends are presented for small catalyst and non-catalyst fleets, and for an individual non-catalyst car and an individual catalyst car. It was found that the trip speed for the road was the most important factor, with the speed fluctuation, in most cases, being of less importance.

The Effect of Fumigation of Different Ethanol Proofs on a Turbocharged Diesel Engine

Lower proof ethanol is shown to be a viable alternate fuel for diesel engines. This type of ethanol can be manufactured economically in small distillation plants from renewable grain supplies. The effect of fumigation of ethanol proofs with a multipoint injection system on a turbocharged direct injection diesel engine at 2,400 rpm and three loads was studied. The addition of the water in the lower proofs reduced the maximum rate of pressure rise and peak pressure from pure ethanol levels. Both of these values were significantly higher than those for diesel operation. HC and CO emissions increased several times over diesel levels at all loads and also with increased ethanol fumigation. NO emissions were reduced below diesel levels for lower proof ethanol at all loads. The tests at this rpm and load with a a multipoint ethanol injection system indicate that lower (100 or 125) proof provides optimum performance.

Compact and Accurate Turbocharger Modelling for Engine Control

With the current trend towards engine downsizing, the use of turbochargers to obtain extra engine power has become common. A great difficulty in the use of turbochargers is in the modelling of the compressor map. In general this is done by inserting the compressor map directly into the engine ECU (Engine Control Unit) as a table. This method uses a great deal of memory space and often requires on-line interpolation and thus a large amount of CPU time. In this paper a more compact, accurate and rapid method of dealing with the compressor modelling problem is presented. This method is physically based and is applicable to all turbochargers with radial compressors for either Spark Ignition (SI) or diesel engines.

Solubility of gasoline components in different lubricants for combustion engines determined by gas—liquid partition chromatography

Abstract The solubility of typical gasoline fuel components in different lubricants for gasoline engines was determined at temperatures between 90 and 150°C. Solubility is an important parameter in combustion engine research, as the fuel during intake and compression dissolves in the lubricant film on the cylinder wall, thus escaping from the combustion processes. During the expansion and exhaust stroke the fuel is desorbed again and in this way contributes to the formation of unburned hydrocarbons in the exhaust gas. The solubility is characterized by Henrys constant. A gas—liquid partition chromatographic techniques was used for the determination of Henrys constants, and gave values in good agreement with the known values for selected reference components.

Dimethyl Ether (DME) - Assessment of Viscosity Using the New Volatile Fuel Viscometer (VFVM)

(VFVM) DTU Orbit (30/09/2019) Dimethyl Ether (DME) Assessment of Viscosity Using the New Volatile Fuel Viscometer (VFVM) This paper describes the development and test of a viscometer capable of handling dimethyl Ether (DME) and other volatile fuels. DME has excellent combustion characteristics in diesel engines but the injection equipment can break down prematurely due to extensive wear when handling this fuel. It was established, in earlier work, that the wear in the pumps is substantial even if the lubricity of DME is raised to a believed acceptable level using anti-wear additives. An influence of the viscosity on the wear in the pumps was suspected. The problem, up to now, was that the viscosity of DME has only been estimated or calculated but never actually measured. In the present work a volatile fuel viscometer (VFVM) was developed. It is of the capillary type and it was designed to handle DME, neat or additised. The kinematic and dynamic viscosities of pure DME were measured at 0.185 cSt and 0.122 cP at 25 oC respectively. The VFVM established that low concentrations of additives do not affect the viscosity of DME significantly. This is the case even when the additive has a high viscosity or is solid at ambient temperature. The viscosity of DME blends can reach that of diesel oil but only when the additive is present in very large proportions. It is not believed that reasonably additised DME can reach the same viscosity and lubricity as diesel oil. The solution is rather to design the pumps so they can handle pure DME.

Ignition Delay in the Dual Fuel Engine

Tests have been conducted on a special compression ignition research engine to investigate the effects of gaseous fuels on the ignition delay in dual fuel engines. Diesel oil, n-heptane, or cetane were used as pilot fuels, and hydrogen, carbon monoxide, or methane were inducted in the intake manifold. Induction of nitrogen was used as a reference to eliminate the influence of changes in oxygen concentration and specific heats. Helium was inducted in additional tests. From the results of a number of parameter variations, the cylinder charge temperature (determined by intake temperature and compression ratio), the pilot fuel amount, and the flow of combustible gas were found to have the most significant influence on the ignition delay.

A model for hydrocarbon emissions from SI engines

A model which calculates the hydrocarbon emissions from an SI engine is presented. The model was developed in order to obtain a better understanding of experimental results from an engine operating on different fuels and lubricants. The model is based on the assumptions that fuel is stored in crevices and oil film during intake and compression followed by desorption during expansion and exhaust. The model also calculates the amount of desorbed material that undergoes in-cylinder oxidation and exhaust port oxidation. The model successfully predicts the trends followed by varying different engine parameters. The effect of changing the lubricant is of the same order of magnitude as found experimentally, but the effect of changing the fuel could not be predicted very well by the model. A possible explanation is that the lubricant film thickness varies due to viscosity variations of the oil film, when the fuel is dissolved in the film. (A) For the covering abstract see IRRD 851463.

A new closing method for wall flow diesel particulate filters

A new method has been developed to close the ends of a wall flow filter used for removing particulate matter from diesel engine exhaust. In this method, the ends of the honeycomb structure are capped by deforming and closing the ends of the channel walls between the extrusion and firing stages of production. The method increases the amount of filtration area per filter volume for a given cell geometry compared to the traditional plugging method, since the entire length of the honeycomb channels is used for filtration purposes. In addition, use of the capping method has a beneficial effect on the pressure loss characteristics of a filter with a given filtration area. These benefits are illustrated through experimental results.

Effects of lubricating oil on hydrocarbon emissions in an Si engine

The effects of lubricant composition on hydrocarbon emissions from a SI engine have been experimentally investigated. In this paper results based on measurements of solubilities of different fuel components in different types of lubricants are presented. The results indicate that the lubricant plays a contributing, but not dominating role in hydrocarbon emissions from gasoline engines.