Browse Publications Technical Papers 872095
1987-11-01

Liquid Propane Injection for Diesel Engines 872095

Propane is one alternative fuel which is already widely available. Its use as a transporation fuel has largely been confined to spark ignition engines, however. This paper reports on an investigation into liquid propane injection as a means for fueling diesel engines.
A single-cylinder CFR cetane rating engine was used to carry out the experimental work. The fuel system was revised to ensure that propane remained liquified in the fuel injection pump and injector. Since propane has a very low cetane number, some means of ignition must be provided. Two means of ignition were evaluated in this investigation, diesel pilot injection and a continuously operating glow plug.
Tests were carried out at compression ratios of 19:1, 22:1 and 25:1 and at engine speeds of 1200, 1500 and 1800 rpm for each of the two ignition methods. The results are similar for the same test conditions. The main advantage of liquid propane injection is reduced smoke emission at a given power output compared to the same engine operating on diesel fuel. Alternatively, for a given smoke limit, the liquid propane injection engine produces significantly more power, about 20% more at full load. The reduction in smoke emission is accompanied by a modest improvement in energy efficiency. Gaseous emissions are comparable to those of the original diesel engine.
The use of glow plug ignition allows complete substitution of propane for diesel fuel, but difficulty was experienced in obtaining reliable ignition throughout the range of engine operating conditions. Proper interaction between the fuel spray and the glow plug is crucial to achieving reliable ignition and reasonable ignition delays. Additional development work is needed to arrive at a combustion chamber geometry which will provide satisfactory operation at all loads and speeds.
Diesel pilot injection provided smooth, reliable ignition at all loads and speeds but requires a second complete fuel system. The amount of diesel fuel used for the pilot injection was typically between 5 and 10% of the total fuel mass.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Preview Document Add to Cart
Members save up to 16% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

Direct Injection Diesel Engine Operated with Propane - DME Blended Fuel

982536

View Details

TECHNICAL PAPER

Study on an Electronically Controlled Common-Rail Injection System for Liquefied Alternative Fuels

2005-01-2085

View Details

TECHNICAL PAPER

Performance and Emissions of a 0.273 Liter Direct Injection Diesel Engine Fuelled with Neat Dimethyl Ether

950064

View Details

X