Abstract

As a consequence of the world-wide energy pinch and ever more stringent emissions requirements, the high-speed diesel engine becomes increasingly important as power plant for passenger cars. This is due to its high thermal efficiency, low exhaust emissions and a noise level which over a wide range of operation only marginally exceeds that of vehicles with gasoline engines. In this presentation, the development of passenger-car diesel engines is delineated, and reasons are given why the combustion systems for passengercar diesels have to be different to those for heavy-duty vehicles. Means and realisable possibilities of reducing noxious emissions, in relation to existing standards, are also explained.

Résumé

Le moteur Diesel rapide prend une importance croissante dans la propulsion de voitures particulières à la suite de la crise mondiale de l'énergie et de la sévérité croissante des normes d'émission. Cela tient à un rendement thermique élevé, à une faible émission de gaz d'échappement et à un niveau sonore qui dans une gamme étendue de fonctionnement ne dépasse guère celui des véhicules équipés de moteur à essence.

On décrit le développement de la propulsion Diesel pour les voitures particulières et on explique pourquoi leur système de combustion diffère de celui des véhicules lourds. On indique aussi les moyens et les possibilités raisonnables de réduire les émissions nocives dans les limites des normes existantes.

1. INTRODUCTION

The origin of the success of the high-speed diesel in passenger cars dates back to the middle of the thirties.

The outstanding popularity of the first passenger-car diesel, chiefly attributed to its excellent economy, resulted in a large development effort in this field.

Whereas in the fifties performance improvements were achieved by raising engine speed and by specific detail improvements, later mainly displacement was increased.

In order to provide diesel vehicles with a roughly equivalent acceleration as compared to gasoline engine powered cars, the displacement of the diesel engine has to be larger by about 35%. With the advancements of traffic, displacement of diesels rose from originally 1.8 1 to 2.2, 2.4 and, lately, even to 3.0 1. While the vehicle with 1.8 1 engine required about 35 sec to accelerate from O to 62 mph, one with 3 1 engine requires only about half of that time and practically matches the acceleration of an identical vehicle with 2.3 1 gasoline engine in US version (model year by K. OBLANDER and H. G. SCHMIDT, Daimler-Benz A.G., 07 Stuttgart 60, Postfach 202, Federal Republic of Germany 1975). Due to the necessary emission control package the gasoline engine loses about 3 sec as compared to its European version, whereas the slight modification for reduction of diesel emissions does not influence performance and acceleration.

Further, improving the acceleration

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