function torque = engine_model_CJP (speed);

%ENGINE_MODEL     Determines the engine torque for a given engine speed
%   TORQUE = ENGINE_MODEL(SPEED) determines the engine torqe for a
%   given engine speed, assuming full throttle
%
%   Inputs:
%      SPEED:     a scalar or vector of engine speed values in [rad/s]
%
%   Outputs:
%      TORQUE:     a vector of the same size as the input SPEED
%                  containing the corresponding engine TORQUE values
%                  expressed in [Nm]
%
%   Assumptions:   all the inputs are within the range from 500 to 6500
%   rpm. Inputs outside that range will result in a warning.
%   
%
%% ME 2016 Section
%% Fall 2007
%%
%% AUTHOR:  Chris Paredis
%%

% first check whether the input is valid
stall_speed = 500*pi/30; %lower limit in [rad/s]
redline_speed = 6500*pi/30; % upper limit in [rad/s]
if any(speed<stall_speed | speed>redline_speed)
    warning(sprintf('input speed must be with the range [%g,%g]rad/s',...
                    stall_speed, redline_speed));
end

% use the Matlab function polyval to evaluate polynomials
poly_coeff = [-6.4e-14, 1.16e-10, -8.3e-8, 2.9e-5, -5.5e-3, 0.76, 170];
torque = polyval(poly_coeff, speed);

return;