Fuel Impact on the Response of AD3.152 UR Engine

The paper presents results of investigations into the AD3.152 UR engine running on five fuels: commercial diesel oil DO, rapeseed oil fatty acid methyl esters FAME and their blends B10 (90% DO + 10% FAME), B20 (80% DO + 20% FAME), B30 (70% DO + 30% FAME). During the tests, the engine operated in accordance with the full load characteristics. Those characteristics were used to determine the engine response. The paper provides an assessment of the impact of the type of plant-derived fuel on the engine response.


Introduction
Rapid developments in piston internal combustion engines, aimed at enhancing the dynamic properties of the vehicle, also contributed to the search for new, environmentally friendly energy sources. Fuels produced from natural raw materials are one of such sources. The advantage those fuels have, when compared with hydrocarbon ones, is that they are renewable, biodegradable and emit less carbon dioxide into the atmosphere [1,2,3]. The response of an internal combustion engine involves an ability to react to variable loads and crankshaft speeds. That provides one of the important indicators of the engine functional properties. The response of the torque depends on the profile of the engine torque characteristics. The magnitude of torque depends on numerous structural and functional parameters [4,5]: the intake system, timing, the fuelling system, physical and chemical properties of fuel, etc. Presently, many research and development centres in the country and in the world conduct investigations to improve the dynamic properties of the internal combustion engine. The purpose of this paper is to analyse whether the use of alternative plant fuels may favourably affect the engine response.
The coefficient of the engine response e is determined on the basis of the profile of curves of variation in the effective power and the engine torque [6,7]. This is the product of the engine torque response e M and the response of the crankshaft rotational speed e n : e = e M ꞏe n (1) The response of the engine torque e M is the ratio of the maximum torque M omax to the torque developed at the engine rated power M oNemax [8]: e m = M omax / M oNemax (2) The response of the rotational speed e n is the ratio of the rotational speed at which effective rated power n Nemax occurs to the rotational speed of the maximum torque n Momax : e n = n Nemax / n Momax (3)

Object of Investigations and the Test Stand
The experimental investigations were performed on the engine test bed, which included the AD3.152 UR engine, the water brake, and the control and measurement cabinet. The diagram of the test bed is shown in Figure 1. The object of investigations was three-cylinder, piston, internal combustion, compression ignition AD3.152 UR engine with fuel direct injection into the combustion chamber located in the piston bottom [9]. The engine was equipped with the fuelling system with the DPA distributor 6 Ambrozik (et al.): Fuel Impact on the Response of AD3.152 UR Engine injection pump. The injectors had four-hole nozzles. Parameters and specifications of the AD3.152 UR engine are presented in Table 1.

Fuels Used to Power AD3.152 UR Engine
During the tests, the AD3.152 UR engine ran on five fuels, namely Ekodiesel Ultra D commercial diesel oil (DO), rapeseed oil fatty acid methyl esters FAME and blends of those two fuels. Tests were conducted for the following blends of hydrocarbon and plant-derived fuels:  10% (V/V) rapeseed oil fatty acid methyl esters FAME + 90% (V/V) Ekodiesel Ultra D diesel oil→ denoted as B10,  20% (V/V) rapeseed oil fatty acid methyl esters FAME + 80% (V/V) Ekodiesel Ultra D diesel oil→ referred to as B20,  30% (V/V) rapeseed oil fatty acid methyl esters FAME + 70% (V/V) Ekodiesel Ultra D diesel oil→ labelled as B30.
Basic physical and chemical properties of Ekodiesel Ultra D diesel oil and rapeseed oil fatty acid methyl esters FAME are presented in Table 2.  Figure 2 shows the full load characteristics of the effective power and torque of the AD3.152 UR engine running on five fuels: DO, FAME, B10, B20 and B30.   Table 3 presents the values of the determined coefficients of the torque response, the rotational speed response and the response of the AD3.152 UR engine running on five fuels: DO, FAME, B10, B20 and B30.

Conclusions
The following conclusions can be drawn on the basis of experimental results: -the maximum effective power for the engine powered by the fuels of concern was found at the same rotational speed of 2000 rpm, -for the engine fuelled by the B30 blend, the maximum torque occurred earlier, i.e. at the rotational speed of 1200 rpm, whereas when engine was powered by the remaining four fuels DO, FAME, B10 and B30, the maximum torque was produced by the engine at the crankshaft rotational speed n=1400 rpm, -the highest value of the rotational speed response, which was equal to e=1.67, was obtained for the engine fuelled by B30, -the torque response, which was e M =1.05÷1.07, was comparable for the engine fuelling with commercial diesel oil, FAME, and also B10, B20 and B30 blends, -when the engine was powered by FAME, and B10, B20 and B30 blends, the higher value of the engine response was obtained when compared with the engine fuelling with commercial diesel oil. The engine powered by the plant-derived fuel and the blends of this fuel demonstrated the strongest ability to overcome the load.