LEAN-LIMIT MIXTURE FUEL INJECTION CONTROL

Información del proyecto

Identificador del acuerdo de subvención: EE.-00183-84

Proyecto cerrado

Fecha de inicio 1 Marzo 1985

Fecha de finalización 28 Febrero 1987

Financiado con arreglo a

• Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985

Coste total

€ 130 095,00

Aportación de la UE

€ 325 149,00

Coordinado por

INSTITUT FRANCAIS DU PETROLE (IFP)
France

Objetivo

To equip a medium-size car with a petrol engine operating with lean -fuel in closed circuit, with the fuel feeding controlled from a lean-mixture-limit sensor, the pollutants level would be reduced
to 4. 6 g/mile for CO, 1 g/mile for NOx and to 0. 51 g/mile for unburned hydrocarbons. The fuel economy compared to a 3-way catalytic converter (stoichiometric air fuel ratio) is expected to reach 5 % equivalent ato 0. 046 TOE/year/car at project level.
Test on a chassis dynamometer were performed with the ECE cycle.
The pollutant emissions results converted to g/mile are: 11.
9 g/mile for CO, 1. 6 g/mile for NO and 5. 5 g/mile for unburned hydrocarbons. They do not attain the goals set based on the US standards, even when these latter have been slightly adjusted by a coefficient of 1. 25 (see Aim). In particular, we find the problem of unburnt hydrocarbon emissions with a lean-burn mixture, which, in this severe context, will probably require the use of an oxidation catalyst. Compared to European standards (EEC forecast converted to g/mile), the results obtained by the demonstration project are encouraging for Carbon Monoxide (CO) and Nitrogen Oxides (NO). The HC + NO level is slightly surpassed because of too high hydrocarbon emissions, due in particular to transcient operation (acceleration response time). The disappointing result with regard to consumption (same level to stoichiometric) is a reflection of the basic engine, whose capacity for lean-burn combustion would have to be improved even further by measures concerning the combustion chamber (swirl caused by the intake). Lastly, the demonstration project revealed the need for a generalized control loop (fuel supply and ignition) that cannot be considered with the basic Renix configuration. Nonetheless, the sensor loop revealed the potential advantage of running near the lean-burn limit with regard to pollutant emissions.
A lean-burn spark-ignition engine is considered as an alternative to the three-way catalyst solution for a clean and low-consumption engine of the future in view of its potential economic advantages. However, the problem of cyclic instabilities as well as misfiring at the lean-burn limit makes sophisticated control of the engine necessary to improve its fuel efficiency while maintaining the driveability of the vehicle. Under the terms of EEC contract nr EE /183/84, the Institut Francais du Petrole (IFP), with the collaboration of Regie Nationale des Usines Renault (RNUR) and Compagnie des Lampes (Lampes Mazda), carried out a demonstration project on a midsized European car. Actually, the starting point of the IFP study was based on a fundamental consideration, namely that the lean-burn limit of a spark-ignition engine fluctuates very widely with the running conditions (speed, load, humidity, etc.. . ) and hence an exhaust-equivalence-ratio sensor can not give a satisfactory answerto the problem. A sensor must be used to detect the quality deterioration of lean-burn combustion. The HC-UV probe was first considered, it is based on the ultraviolet (UV) absorption of the aromatic component of unburnt hydrocarbons (HC), whose presence in the exhaust from a spark-ignition engine is the sign of incomplete combustion upon the opening of the exhaust valve. But the HC-UV could not be used for demonstration on a car because of the difficulty of installing and operating it in the under-hood environment (bulk, need of air intake to prevent the fouling of the optics, too low a signal/noise ratio with regard to electromagnetic interference). Demonstration on a vehicle was achieved by using a new lean-burn limit sensor based on the statistical processing of signals from ionization probes placed inside the combustion chambers (French patent application Nr 87 /09264). When the device is implemented electronically, the signals can be processed and the strategy can be implemented. However, this can be done only with a microprocessor-based technology.
In agreement with RNUR, the Intel 8751 monochip was chosen because it has the particular feature of being able to be installed in the Renix injection computer of the vehicle so as to use the ancillary equipment (power supply voltages, synchronisation, angular signals, etc. . . ). Installation of the computer with feedback from the lean-burn limit sensor was done on a Renault R9 car, which had first been equipped by a Renix multipoint injection F3N engine ( this engine with a displacement of 1721 cm3 powers the standard model of the new Volvo 480).

Ámbito científico (EuroSciVoc)

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Programa(s)

• ENG-ENALT 2C - Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985

Tema(s)

• 3.3 - TRANSPORT

Convocatoria de propuestas

Datos no disponibles

Régimen de financiación

DEM - Demonstration contracts

Coordinador

INSTITUT FRANCAIS DU PETROLE (IFP)

• Aportación de la UE: Sin datos
• Dirección: AVENUE DE BOIS PREAU 1 ET 4 ; 92852 Rueil-Malmaison ; Francia
• Coste total: Sin datos