MATLAB的发动机万有特性曲线绘制方法程序

%不同转速下的燃油消耗率与扭矩的曲线拟合

clear all

be1=[222.8,220.4,232.4,228.5,227.8,232.6,248.5,245.9,272.4,329.7];

Ttq1=[399.8,354.1,318.5,278.1,236.2,203.6,185.3,157.2,117.2,80.8];

T1=80:320/9:400;%转换矩阵格式

Be1=interp1(Ttq1,be1,T1,'spline');%n=1400r/min时燃油消耗率与扭矩的曲线拟合

be2=[222.0,221.7,235.4,226.5,230.5,236.8,249.1,276.1,407.9,487.0];

Ttq2=[409.1,365.7,328.3,284.1,243.7,203.2,164.3,123.9,83.5,39.7];

T2=39:371/9:410;

Be2=interp1(Ttq2,be2,T2,'spline');

be3=[226.0,225.3,226.4,233.9,242.1,283.3,253.9,271.4,323.5,468.6];

Ttq3=[408.3,368.3,328.3,289.0,244.4,208.8,167.7,132.1,89.5,46.1];

T3=46:363/9:409;

Be3=interp1(Ttq3,be3,T3,'spline');

be4=[206.5,231.1,231.1,233.0,242.0,244.9,265.0,299.8,398.0,596.8];

Ttq4=[425.6,380.3,332.7,290.9,244.4,205.1,160.2,114.5,68.8,30.7];

T4=30:396/9:426;

Be4=interp1(Ttq4,be4,T4,'spline');

be5=[234.7,259.8,235.5,237.6,242.8,292.3,277.9,308.7,396.2,605.9];

Ttq5=[420.7,379.6,334.6,291.6,244.4,202.8,157.5,116.0,74.1,37.8];

T5=37:384/9:421;

Be5=interp1(Ttq5,be5,T5,'spline');

be6=[174.2,242.2,252.1,287.4,253.6,263.6,290.6,316.8,378.0,518.8];

Ttq6=[404.6,360.5,322.7,283.0,243.3,205.5,162.1,124.7,86.8,52.4];

T6=52:353/9:405;

Be6=interp1(Ttq6,be6,T6,'spline');

be7=[256.9,253.7,253.5,260.0,303.8,280.7,300.6,346.6,435.6,812.9];

Ttq7=[378.0,344.7,310.3,264.3,226.1,186.8,154.2,115.3,76.3,34.1];

T7=34:344/9:378;

Be7=interp1(Ttq7,be7,T7,'spline');

be8=[257.9,295.3,282.4,288.7,301.9,329.7,357.0,475.4,580.3,1080.1];

Ttq8=[315.6,275.5,242.5,210.3,178.5,145.6,118.6,72.6,52.8,22.4];

T8=22:294/9:316;

Be8=interp1(Ttq8,be8,T8,'spline');

B=[Be1';Be2';Be3';Be4';Be5';Be6';Be7';Be8'];

N=[1400*ones(10,1);1600*ones(10,1);1800*ones(10,1);2000*ones(10,1);2200*ones(10,1);2400*ones (10,1);2600*ones(10,1);2800*ones(10,1)];

Ttqn=[T1';T2';T3';T4';T5';T6';T7';T8'];

G=[ones(80,1),N,Ttqn,N.^2,N.*Ttqn,Ttqn.^2];

A=G\B;%A为6*1矩阵

[n,Ttq]=meshgrid(1400:2800,100:600);%生成n-Ttq平面上的自变量“格点”矩阵

be=A(1)+n.*A(2)++Ttq*A(3)+n.^2*A(4)+n.*Ttq*A(5)+Ttq.^2*A(6);

Pe=Ttq.*n/9550;

%外特性实验数据拟合

Nw=[1403,1597,1797,1986,2102,2199,2303,2400,2507,2598,2700,2802];

Ttqw=[474,497,515,526,528.8,522.8,509.5,492.2,471.2,448.4,408.3,357.4];

n0=1400:2800;

Ttqw_N=interp1(Nw,Ttqw,n0,'spline');

h=repmat(Ttqw_N,501,1);

ii=find(Ttq>h);%确定超出边界的“格点”下标

be(ii)=NaN;%强制为非数

Pe(ii)=NaN;%强制为非数

%绘制等燃油消耗率曲线和等功率曲线三维拟合图

subplot(1,2,1);

mesh(n,Ttq,be);

hold on;

mesh(n,Ttq,Pe);

axis([1000,3000,100,600,0,500]);

hold on;

xlabel('n(r/min)')

ylabel('Ttq(N*m)')

zlabel('Pe(KW) be(g/(KW*h))')

title('等燃油消耗曲线和等功率曲线的三维拟合图')

%绘制边界线(外特性曲线)

subplot(1,2,2);

plot(n0,Ttqw_N,'LineWidth',2);

axis([1400,2800,100,550]);

xlabel('n(r/min)');

ylabel('Ttq(N*m)');

title('万有特性曲线');

hold on;

%绘制等油耗率曲线的二维图

B=contour(n,Ttq,be,11);%画等位线，并给出标识数据

clabel(B);%把“等位值”沿等位线随机标识

hold on;

%绘制等功率曲线的二维图

P=contour(n,Ttq,Pe,11);%画等位线，并给出标识数据

clabel(P);%把“等位值”沿等位线随机标识

legend('等油耗曲线','等功率曲线','外特性曲线')

hold off

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