APPENDIX 1 SPECIFICATION OF THE TEST ENGINE

Transcription

1 143 APPENDIX 1 SPECIFICATION OF THE TEST ENGINE Make and model : Kirloskar, AV-1 make General Details : Four stroke, Compression ignition, Constant Speed, vertical, water cooled, direct injection. Number of cylinders : one Bore : 80 mm Stroke : 110 mm Swept volume : 553 cc Clearance volume : cc Compression ratio : 16.5 : 1 Rated output : 3.67 kw at 1500 rpm Rated speed : 1500 rpm Injection pressure : 00 bar Fuel injection timing : 3 deg CA BTDC Type of combustion chamber : Hemispherical open combustion chamber Fuel : High Speed diesel Lubricating oil : SAE 40 Connecting rod length : 35 mm Valve diameter : 33.7 mm Maximum valve lift : 10. mm

2 144 APPENDIX ELECTRICAL DYNAMOMETER Make and Model : Laurence Scott and electromotor Ltd., Norwich and Manchester, UK Volts : 0/30 Maximum power : 10 kw Windings : Shunt Rated current : 43.5 A RPM : 1500 Rating type : Continuous Machine No. : APPENDIX 3 EXHAUST GAS ANALYSER Automotive exhaust gas analyzer Model QRO 40 Make: QROTECH CO LTD., Korea Measuring item Measuring method Measuring range Resolution CO (%) NDIR HC(ppm) NDIR CO (%) NDIR NOx(ppm) Electrochemical

3 145 APPENDIX 4 SMOKE METER Type and make : TI diesel tune, 114 smoke density tester TI Transervice Piston displacement : 330 cc Stabilisation time : minutes Range : 0 10 Bosch smoke number Minimum time period : 30 sec Calibrated reading : 5.0 ± 0. APPENDIX 5 PRESSURE TRANSDUCER Model : KISTLER, Switzerland. 601 A, water cooled. Range : 0 to 50 bar Sensitivity : pc/ bar Linearity : 0.1 < ± % FSO Acceleration sensitivity : <0.001 bar/g Operating temperature range : -196 to 00 0 C Capacitance : 5 pf Weight : 1.7 g Connector, Teflon insulator : M4 x 0.35

4 146 APPENDIX 6 CATHODE RAY OSCILLOSCOPE Make : Hewlett Packard, HP54600B SERIES Channels : Nos. Range : mv/div to 5V/div Accuracy : ±1.5% Verniers : finely calibrated Band width limit : 0 MHZ Trigger System dc to 100 MHZ 1 div or 10 m V Modes : Auto Hold off : Adjustable from 00 ns to 135 External Trigger Range : ±18V Sensitivity : dc to 100 MHZ 100mV Input resistance : 1 M Input capacitance : 13 pf Display System 7 inch raster CRT Resolution 55 vertical by 500 horizontal points

5 147 Acquisition System Maximum sample rate : 0 MSa/s Resolution : 8 bits Advanced Functions Voltage : Varg, Vrms, Vp-p, Vtop, Vbase, Vmin, Vmax Time : Frequency, period, +width, -width, duty cycle, rise time and fall time Cursor : manual or automatic Autoscale : Vertical / Horizontal Power : Line Voltage 100 Vac to 40 Vac Maximum power : 0VA Consumption Line Voltage selection-automatic Line Voltage frequency-45 HZ to 440 HZ General Humidity : 95% Rh +40 C Temperature : -10 C to 55 C MIL-T-8800D for type III, class 3, style D EMI MIL-T- FTZ 1046 Class B Vibration : 15 min along each of 3 xy axis Displacement, 10 HZ to 55 HZ in one man cycle Weight : 6. Kg.

6 148 APPENDIX 7 CHARGE AMPLIFIER Make : KISTLER Instruments AG, Switzerland Measuring ranges : 1 stages graded pc ± ::5 and stepless 1 to 10 Transducer sensitivity, 5 decades : (*) pc/m.u. 0, Continuously adjustable between Accuracy Of two most sensitive ranges % <± 3 Of other range stages % <±1 Linearity of Transducer Sensitivity % <±0,5 Potentiometer adjustment Calibration capacitor pf 1 000±0,5 Calibration input, sensitivity pc/mv 1±0,5 Input Voltage, maximum with pulses V ±15 Widths < 0, 3 s Linearity (**) %FSO <±0,05 Frequency response error with standard Filter 180 khz at 50 khz % at 100 khz % <±5 3-dB-frequency with standard filter khz 180±10% 180 khz, input capacitance up to 00 pf Time constant resistor setting Long, about setting Medium, about setting Short 10 9 Time constant, = R g C g setting Long s >1 000 >

7 149 setting Medium s setting Short s Voltage output, unlimited short circuit proof Full scale output (**) V ±10 Output current ma ±5 Output impendance 100±5% Open circuit saturation voltage V >±1..< ±15 Cable noise signal, due to input capacitance pc rms /pf < Hum and noise, input shielded (***) mv rms <0,3/< Zero offset during reset, over 10 hrs. (***) mv <±1 / <±5 Zero error, during reset, due to supply Voltage variations±0% (***) mv <±1 / <±10 Thermal zero shift, during reset Due to temperature changes (***) mv/ C <±0,5 / <±5 Drift, due to leakage current of input pc/s <±0,03 MOSFET, at 0 C Adjustment range for zero offset, input stage mv ±00 Output stage mv ±50 (*) M.U. = mechanical unit, e.g. Bar, N, g. (**) FSO = full scale output (***) Dial for transducer sensitivity adjustment set to resp. 1-00

8 150 APPENDIX 8 ELECTRONIC BALANCE Make : SHIMADZU, Japan Model : AY6 Weighing capacity : 6 g Minimum display : 0.1 mg Standard deviation ( ) : mg Linearity : ± 0. mg External weight value for : 60 g Calibration Pan diameter : Ø 80 mm Stability of sensitivity : ± ppm / C (10 C to 30 C) Operating temperature : ± 5 to 40 C Range Power supply : Input VAC APPENDIX 9 TACHOMETER Make : FUJI, Japan Type : MECHANICAL Range : 0 10,000 rpm Resolution : 0 rpm

9 151 APPENDIX 10 HOT AIR OVEN Name : SRICO electric hot air oven with digital temperature Controller Power supply : 0 V, 50 Hz. Temperature range : C Accuracy : 1 C Mode of control : Auto-digital controller Mode of heating : Imported BDG 80 / 0 nickel wire

10 15 APPENDIX 11 ERROR AND UNCERTAINTY ANALYSIS Error is associated with various primary experimental measurements and the calculations of performance parameters. Errors and uncertainties in the experiments can arise from instrument selection, condition, calibration, environment, observation, reading and test planning. Uncertainty analysis is needed to prove the accuracy of the experiments. The percentage uncertainties of various parameters like load and brake thermal efficiency were calculated using the percentage uncertainties of various instruments given in Table 3.. An uncertainly analysis was performed using the equation Total percentage uncertainty = Square root of{(uncertainty of TFC) +(uncertainty of load) + (uncertainty of brake thermal efficiency) + (uncertainty of CO) + (uncertainty of unburned HC) + (uncertainty of NOx) + (uncertainty of smoke number) + (uncertainty of exhaust gas temperature) + (uncertainty of pressure pickup) } = square root of {(1) + (0.) + (1) + (0.) + (0.) + (0.) + (1) + (0.15) + (1) } = ±.8 %

11 153 The errors associated with various measurements and in calculations of performance parameters are computed in this section. The maximum possible errors in various measured parameters namely temperature, pressure, exhaust gas emissions, time and speed estimated from the minimum values of output and accuracy of the instrument are calculated using this method. This method is based on careful specification of the uncertainties in the various experimental measurements. If an estimated quantity, R depends on independent variable like(x 1, x, x 3. x n) then the error in the value of R is given by R = f (x 1, x,... x n ) (A 11.1) with `R as the computed result function of the independent measured variables x 1, x, x 3,... x n, as per the relation. x 1, ± x 1, x ± x,..., x a ± x a as the error limits for the measured variables or parameters and the error limits for the computed result as R ± R To get the realistic error limits for the computed result, the principle of root-mean square method was used to get the magnitude of error given by Holman 1973 R R x 1 x 1 R x x R... xn x n 1/ (A11.) Using equation A11. the uncertainty in the computed values such as load, brake thermal efficiency and fuel flow measurements were estimated. The

12 154 measured values such as speed, fuel time, voltage and current were estimated from their respective uncertainties based on the Gaussian distribution. The uncertainties in the measured parameters, voltage ( V) and current ( I), estimated by the Gaussian method, are ± 3 V and ± 0.14 A respectively. For fuel time ( t r ) and fuel volume ( t), the uncertainties are taken as ± 0. sec and ± 0.1 sec respectively. A sample calculation is given below Example: Speed N = 1500 rpm Voltage V = 30 volts Current I = 14 A Fuel volume fx = 10 cc Brake power BP = 3.74 kw 1. Brake power BP g VI kw x 1000 BP = f(v,i) BP V I (0.86x1000) 14 (0.86x1000) BP I V (0.86x1000) 30 (0.86x1000) BP BP V BP V I (A11.3) I

13 x x 0.14 = = kw Therefore, the uncertainty in the brake power from equation A11.3 is ± kw and the uncertainty limits in the calculation of B.P are 3.74 ± kw.. Total fuel consumption (TFC) TFC TFC 10 x 3600 x 0.85 (t x1000) 10 x 3600 x 0.85 (9.3 x 1000) kg / h TFC = f(t) tfc T tfc T (10x 3600x 0.85) t x1000 (10 x 3600 x 0.85) kg/h (9.3) x 1000 TFC TFC x t t (A11.4) t ( x 0.) = kg/h The uncertainty in the TFC from equation A11.4 is kg/h and the limits of uncertainty are ( ) ± ( ) kg/h. 3. Brake thermal efficiency ( )

14 156 BP x 3600 x 100 TFC x CV = f (BP, TFC) 3.74 x 3600 x x % BP (3600 x 100) TFC x x100 ( x 43000) TFC (BP x 3600 x100) (TFC) x (3.74 x 3600 x 100) ( ) x = 8.70 % x BP BP TFC x TFC (A11.5) ( x ) (8.70 x ) = % The uncertainty in the brake thermal efficiency from equation A11.5 is ± % and the limits of uncertainty are ± % 4. Exhaust Gas Temperature Measurement Al/Cr K-type thermocouple is used to measure the exhaust gas temperature. Digital temperature indicator displays the temperature measured by thermocouple. The maximum possible error in the case of temperature

15 157 measurement is calculated from the minimum values of the temperature measured and accuracy of the instrument (thermocouple with temperature indicator) the errors in the temperature measurement are: T/T) EGT = (( T k-type / T k-type ) + ( T indi / T indi ) ) 1/ T/T) EGT = ((0.48/160) + ( 0.468/ 160 ) ) 1/ T/T) EGT = =0.41% 5. Combustion chamber pressure measurement The combustion chamber pressure was measured by using pressure transducer and charge amplifier. P/P) Exp = (( q charge / q charge ) + ( V PT / V PT ) ) 1/ P/P) Exp = ((0.16/ 100) + (0.15/ 100) ) 1/ = = 0.% 6. Percentage of uncertainty for the measurement of speed, mass flow rate of air, mass flow rate of diesel, NO x, hydrocarbon and smoke is given below: i) Speed : 1.1 ii) Mass flow rate of air : 1.3 iii) Mass flow rate of diesel : 1.0 iv) NO X : 1.1 v) Hydrocarbon : 0.01 vi) CO : 0.8 vii) CO : 1. vi) Smoke :.0

16 158 APPENDIX 1 HEAT RELEASE ANALYSIS The details about combustion stages and events can be determined by analyzing the heat release rates determined from cylinder pressure measurements. Analysis of heat release can help to study the combustion behaviour of the engine. The analysis for the heat release rate is based on the application of first law of thermodynamics for an open system. It is assumed that the cylinder contents are homogeneous mixture of air and combustion products and are at uniform temperature and pressure during the combustion process. The first law for such a system is written as dq hr = du + dw + dq ht (A1.1) where, dq hr = Instantaneous heat release modeled as heat transfer to the working fluid du = dw = Change in internal energy of the working fluid Work done by the working fluid dq ht = Heat transmitted away from the working fluid (to the combustion chamber walls) Change in internal energy is written as, du = C v /R (pdv+vdp) (A1.)

17 159 Work done by the working fluid dw = pdv Heat transfer rate to the wall is written as dq ht /dt = h A (T g -T w ) (A1.3) where R = Gas constant T,P,V are Temperature, Pressure and Volume respectively. C v = Specific heat at constant volume h = Heat transfer co efficient T w = Temperature of the wall: 400 K h B p T w Where B (bore) = m P(cylinder pressure) = 9.37 bar T (gas temperature) = 100 K w is average gas velocity in m/s which is calculated from the equation w C S C V T ( p p d c 1 p m pcvc ) (A1.4) Where S P is the mean piston speed in m/s, V d is the displaced volume in m 3 T c, p c, V c are temperature, pressure and volume respectively during combustion p is the cylinder pressure during combustion p m is the pressure in motorized condition C 1 is.8 and C is 3.4x10-3 during combustion

18 160 From the equation, the first law of thermodynamics can be written as follows with suitable assumptions: dq ht dv P 1 d V 1 dp 1 d ha s (Tg dt Tw) d (A1.5) Where is the crank angle in degrees is the ratio of specific heats of the fuel and air A s is the area in m through which heat transfer from gas to combustion chamber walls takes place. The pressure value is obtained from the cylinder pressure data at corresponding crank angle. Equation (A1.1) makes it possible to calculate the heat release rate. The calculated heat release rate is as follows with the given values Clearance volume = 3.68x10-5 m 3, Swept volume = m 3 =1.3, Crank radius = 0.055m Stroke = 0.11 m, Compression ratio = 16.5 At 350 O CA the pressure is bar and at 351 O CA the pressure is bar. The heat release rate is dq ht dv P 1 d V 1 dp 1 d ha s (Tg dt Tw) d dq ht dq ht ( ) dqht 87.6 Joules/ºCA

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