Compression & firing pressure

Compression & firing pressure

 

Calculations

Traction HP/ In put Traction  =(V x I)/700=(730 x2160)/700 = 2252.6         

 Corrected HP =(Traction HP)/a.b.c= 2252.6/0.98 = 2298

 BHP=  Corrected HP+186 =2298 +186=2484 HP

 

(Note :       Value of BHP should come near to 2600HP but it is not, may be due incorrect    assumption of Traction/Gen. efficiency and varying Atm.temp. etc )

 

S F C

Introduction

In IR, Fuel Consumption of a diesel locomotive is expressed in two defined way –

💧SFC in term of gm/Hp.hr.

💧SFC in term of litre/1000GTKM.

💧SFC in term of gm /Hp.hr

💧Fuel consumption is measured in term of gm/(HP.hr) and calculated during Load box testing of loco.

💧It is defined as the  amount of fuel required to generate unit horse power per hour.

💧It is calculated by using the given formula-

SFC= (Consumption of fuel in gm)/BHP x time in Hr

Process of measurement in gm/HP.hr

SFC Calculation in gm/HP.Hr(WDM2/2600HP loco)

Generator voltage         :     568V volts

Generator current         :     2901 Amp

Generator efficiency       :  0.935(assumed 93.5%)

Traction HP= (568 x 2901)/0.935x746 =2364.89HP 

BHP= (Traction HP/X*Y*Z)+AHP = (2364.89/ 0.9878x1x1)+186=2580HP.

In WDM2,AHP=Power consumed by the Auxiliaries=186 HP

Where, At 36’C Air intake temp,X=(0.9878),Y=(1)& Z=(1)

SFC= (10000 gms x 3600 )/(88x 2580) = 158 gms/HP/Hr

SFC in term of Litre/1000GTKM

🔍It is measured in term of Ltrs/1000GTKM when loco is doing service and hauling the train.

🔍SFC is the  ratio between the fuel consumed and load hauled.

🔍It is calculated by using the given formula-        SFC= (Fuel oil Consumption in Litres x1000)/(Load in tonnage xKM earned

SFC  CALCULATIONS in Litre /1000GTKM

This method for calculation of SFC is adopted, when loco is in service and working in train.

SFC= (Fuel oil Consumption in Litres x1000)/(Load in tonnage x KM earned)

Example:

From “TRIP CARD”,the following deta are collected .(This deta is for passenger train hauled by WDM2/2600HP loco)

KM earned                          :        232 KM (BGP to DNR)

 Fuel oil consumption                        :        1050 Ltrs

 Load on train(15 coaches)      :            60x15+113=1013 tons

SFC= (1050x1000)/(1013x232)=4.46 ltrs/1000GTKM.

(Note : This is not standard value, it is based on practical observation)

As a loco maintainer how can reduce excess fuel consumption?

💢Ensure perfection of loco wheel profile.

💢Avoid Brake binding in train .

💢Set temperature for operation of R/fan.

💢Compression pressure and Firing pressure must be check.

💢Ensure SFC calculated during load box testing is within range.

💢Ensure that Dynamic brake on loco is functioning properly.

💢Use Dynamic brake to control the train .

💢Blow bye testing must be conducted in schedule .

💢After cooler must be cleaned and tested in schedule.

💢Properly overhauled and tested FI & FIP are only to be fitted.

💢Pipes to be properly clamped to ensure no leakages.

💢Ensure required booster pressure at different notch.

How to reduce excess fuel oil consumption?

💢No of stoppage of train should be bare minimum (Commercial dept).

💢Reduce number of caution order to  minimum(Civil engg).

💢Curved line impose speed restriction resultant in excess fuel oil consumption.(Civil engg)

💢Avoid Signal failure and Poor visibility of signal.(Sig.& Tel dept).

💢Minimize detention of train in yard.(commercial dept).

💢Try to run the train on constant speed as possible as per instructions.(C&W).

💢Try to avoid deceleration and acceleration of the train.(C&W)

💢Idle running of engine and idle movement of loco must be avoided.

 

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