6837092900

Diagnostyka’ 4(48)/2008    15

KEKEZ, AMBROZIK, RADZISZEWSKI, Modeling of Cylinder Pres surę in Compression Ignition Engine ...

Table 2. Parameters of output scaling function

Para meter	Yalue
^a°	p,.fora whenfd^2pĄ	for diesel oil
“l	WL	for a new fuel (e.g. FAMĘ)
		for diesel oil
*3		for a new fuel (e.g. FAMĘ)

The output scaling function y'= f(y) has the form given by the eąuation:

y —— for y <a₀

y=| _a ^a°    (i)

(y-ao)'°³_fl²'^+g2 foryŁao

where a₀,a_x,a₂,a₂ values are calculated in the way given in Table 2.

The idea of calculation of a₀,a_ha₂,a₃ parameters is shown in Fig. 3. After the calculation of output scaling parameters, we also calculate a_A parameter value for input scaling, which "moves” pressurc curve along with horizontal axis. We select a value of “move” for which mean indicated pressure is calculated with highest accuracy.

The results are quite good: we acquired Takagi-Sugeno model for diesel oil, which has good accuracy (mean indicated pressure error less than 3.9% and maximum pressure error less than 2.1%, for all rotational speeds). Later, we measured cylinder pressure curve for FAMĘ fliel, at 1200 rpm and calculated parameters of input and output scaling functions. The resulting model (Fig. 4) had also good accuracy (mean indicated pressure error less than 4.1% and maximum pressure error less tlian 2.6%, for all rotational speeds).

4. CONCLUDING REMARKS

During experimental research the cylinder pressure curves in function of crankshaft angle were recorded while engine was fueled with diesel oil and FAMĘ. The results of measurements for diesel oil allowed building of model of engine work by means of GFSm system. The acquired model was later “tuned” for FAMĘ fuel, by using input and output scaling in fuzzy model. The resulting model has good accuracy for both diesel oil and FAMĘ (mean indicated pressure error less than 4.1% and maximuin pressure error less than 2.6%).

4. CONCLUDING REMARKS

During experiinental research the cylinder pressure curves in function of crankshaft angle were recorded winie engine was fueled with diesel oil and

FAMĘ. The results of measurements for diesel oil allowed building of model of engine work by means of GFSm system. The acquired model was later luned” for FAMĘ fuel, by using input and output scaling in fuzzy model. The resulting model has good accuracy for both diesel oil and FAMĘ (mean indicated pressure error less than 4.1% and maximum pressure error less than 2.6%).

c)    d)

Fig. 3. Idea of calculation of parameters and work of output scaling function: a) experimental cylinder pressure curve p_c when engine operated in extemal speed characteristic regiine at 1200 rpm and was fueled by diesel oil and idea of calculation of a₀ and a_x values, b) experiinental cylinder pressure curve p_c when engine operated in extemal speed characteristic regime at 1200 rpm and was fueled by a new fuel (e.g. FAMĘ) and idea of calculation of a₂ and values, c) modeled cylinder pressure curve p_c for any given rotational speed, without output scaling (for diesel oil) d) modeled cylinder pressure curve p_c for any given rotational speed, with output scaling (for new fuel, e.g. FAMĘ)