Code below show the calculation of fuel economy of conventional car, you are required to modifiy the code of MATLAB below by adding hydraulic system (hydraulic hybrid system) into the conventional car to calculate its fuel economy. Given the sizing of components of hydraulic: Accumulator; Pcharge=10MPa, Pmax= 40MPa, Pressure ratio,r=3.8, Volume of accumulator=6.3 litre, Accumulator efficiency=98%

Pump/Motor; 50cc/rev displacement

close all clear all clc

[R_tire,A,Cd,density_air,density_fuel,m,g,Cr,fc,fc_max,S_map,T_map,Te_max,gamma,Ppre,Pmin,Pmax,Vmin,Vmax,Disp,eff_mech,eff_hyd] = Parameter; [BSFC,FC,M,I] = fuelmap(fc,S_map,T_map);

DC = {'A:A' 'B:B' 'C:C' 'D:D' 'E:E' 'F:F' 'G:G' 'H:H' 'I:I' 'J:J' 'L:M'}; speed = xlsread('Drive cycle.xlsx',DC{1});

Distance = 0; Total_fuel = 0; Final_time = size(speed,1);

if size(speed,2)==2 time = speed(:,1); speed = speed(:,2); else time = 1:Final_time; end

%Inital SOC SOC = 0.5; %Initial engine state: 1 = on , 0 = off k = 1;

for i = 1:Final_time Current_speed = speed(i); if i ~= Final_time Next_speed = speed(i+1); end if i ~= Final_time duration = time(i+1)-time(i); else duration = 0; end %Properties of nitrogen gas P = SOC*(Pmax-Pmin)+Pmin; V = Vmax*((Ppre/P)^(1/gamma)); %ideal gas law, ok accel = acceleration(i,Current_speed,Next_speed,Final_time,duration); [T_wheel,S_wheel] = Wheel(R_tire,A,Cd,density_air,m,g,Cr,accel,Current_speed); Tw(i) = T_wheel; gearratio = Gearratio(Current_speed,T_wheel,S_wheel); %depends on speed of vehicle S_engine = EngSpeed(S_wheel,gearratio); [T_engine,T_pm] = EngTorque(Current_speed,gearratio,T_wheel,S_engine,I,P,Disp,eff_mech,eff_hyd); [SOC,k,T_engine,S_engine,T_brake,T_pump] = strategy(duration,gamma,P,V,Pmin,Pmax,Vmin,Vmax,SOC,Disp,T_wheel,S_wheel,gearratio,S_map,Te_max,T_engine,S_engine,T_pm,k,eff_mech,eff_hyd); SOC_t(i) = SOC; Speed_engine(i) = S_engine; Torque_engine(i) = T_engine; Torque_brake(i) = T_brake; Tpump(i) = T_pump; T_sum = check(T_engine,T_pump,T_wheel,T_brake,eff_mech,eff_hyd,gearratio); Torque_check(i) = T_sum; fuel = fuel_consumption(duration,T_engine,S_engine,fc,S_map,T_map,Te_max,fc_max,k); Total_fuel = Total_fuel+fuel; Distance = Distance + Current_speed*duration; end

fuel_economy = (Distance/1000)/(Total_fuel/density_fuel) %km/L

subplot (4,1,1), plot (time,speed); title ('Graph of vehicle speed vs time'); xlabel ('Time (s)'); ylabel ('Speed (m/s)'); set(gca,'Ytick', 0:10:40); grid on

subplot (4,1,2), plot (time,SOC_t); title ('Graph of SOC vs time'); xlabel ('Time (s)'); ylabel ('SOC'); set(gca,'Ytick', 0:0.25:1); grid on

subplot (4,1,3), plot (time,Torque_engine); title ('Graph of engine operating torque vs time'); xlabel ('Time (s)'); ylabel ('Engine torque (Nm)'); set(gca,'Ytick', 0:20:100); grid on

subplot (4,1,4), plot (time,Speed_engine); title ('Graph of engine speed vs time'); xlabel ('Time (s)'); ylabel ('Speed (rpm)'); set(gca,'Ytick', 0:1000:4500); grid on

figure plot(Torque_check); title('Balance of torque')