{
    volScalarField& rDeltaT = trDeltaT.ref();

    const dictionary& pimpleDict = pimple.dict();

    // Maximum flow Courant number
    scalar maxCo(pimpleDict.lookup<scalar>("maxCo"));

    // Maximum time scale
    scalar maxDeltaT(pimpleDict.lookupOrDefault<scalar>("maxDeltaT", great));

    // Smoothing parameter (0-1) when smoothing iterations > 0
    scalar rDeltaTSmoothingCoeff
    (
        pimpleDict.lookupOrDefault<scalar>("rDeltaTSmoothingCoeff", 0.1)
    );

    // Damping coefficient (1-0)
    scalar rDeltaTDampingCoeff
    (
        pimpleDict.lookupOrDefault<scalar>("rDeltaTDampingCoeff", 1.0)
    );

    // Maximum change in cell temperature per iteration
    // (relative to previous value)
    scalar alphaTemp(pimpleDict.lookupOrDefault("alphaTemp", 0.05));

    // Maximum change in cell concentration per iteration
    // (relative to reference value)
    scalar alphaY(pimpleDict.lookupOrDefault("alphaY", 1.0));

    // Cache old reciprocal time scale field
    volScalarField rDeltaT0("rDeltaT0", rDeltaT);


    Info<< "Time scales min/max:" << endl;


    // Flow time scale
    {
        surfaceScalarField maxPhi("maxPhi", phi);

        forAll(phases, phasei)
        {
            maxPhi = max(maxPhi, mag(phases[phasei].phi()));
        }

        // Set the reciprocal time-step from the local Courant number and
        // limit the largest time scale
        rDeltaT.ref() = max
        (
            1/dimensionedScalar(dimTime, maxDeltaT),
            fvc::surfaceSum(maxPhi)()()
           /((2*maxCo)*mesh.V())
        );

        Info<< "    Flow = "
            << gMin(1/rDeltaT.primitiveField())
            << ", " << gMax(1/rDeltaT.primitiveField()) << endl;
    }


    // Heat release rate time scale
    if (alphaTemp < 1)
    {

        autoPtr<phaseSystem::heatTransferTable>
            heatTransferPtr(fluid.heatTransfer());

        phaseSystem::heatTransferTable& heatTransfer = heatTransferPtr();

        volScalarField::Internal rDeltaTT
        (
            volScalarField::Internal::New
            (
                "rDeltatTT",
                mesh,
                dimensionedScalar(rDeltaT.dimensions(), 0)
            )
        );

        forAll(fluid.anisothermalPhases(), anisothermalPhasei)
        {
            phaseModel& phase = fluid.anisothermalPhases()[anisothermalPhasei];

            tmp<volScalarField> rho = phase.rho();
            tmp<volScalarField> Cp = phase.thermo().Cp();
            tmp<volScalarField> T = phase.thermo().T();

            // Heat release due to combustion is not included due to missing
            // access from the phaseModel
            rDeltaTT.field() = max
            (
                rDeltaTT,
                (
                    mag(heatTransfer[phase.name()]->source())
                  + mag(fvModels.source(rho, phase.thermoRef().he())->source())
                )
               /(alphaTemp*rho*Cp*T*mesh.V())
            );
        }

        Info<< "    Temperature = "
            << 1/(gMax(rDeltaTT.field()) + vSmall) << ", "
            << 1/(gMin(rDeltaTT.field()) + vSmall) << endl;

        rDeltaT.ref() = max(rDeltaT(), rDeltaTT);
    }


    // Reaction rate time scale
    if (alphaY < 1)
    {
        dictionary Yref(pimpleDict.subDict("Yref"));

        autoPtr<phaseSystem::specieTransferTable>
            specieTransferPtr(fluid.specieTransfer());

        phaseSystem::specieTransferTable&
            specieTransfer(specieTransferPtr());

        volScalarField::Internal rDeltaTY
        (
            volScalarField::Internal::New
            (
                "rDeltaTY",
                mesh,
                dimensionedScalar(rDeltaT.dimensions(), 0)
            )
        );

        bool foundY = false;

        forAll(fluid.multiComponentPhases(), multiComponentPhasei)
        {
            phaseModel& phase = fluid.anisothermalPhases()[multiComponentPhasei];
            
            UPtrList<volScalarField>& Y = phase.YActiveRef();
            tmp<volScalarField> rho = phase.rho();

            forAll(Y, i)
            {
                volScalarField& Yi = Y[i];

                if (Yref.found(Yi.member()))
                {
                    foundY = true;
                    scalar Yrefi = Yref.lookup<scalar>(Yi.member());

                    rDeltaTY.field() = max
                    (
                        rDeltaTY,
                        (
                            mag(specieTransfer[Y[i].name()]->source())
                          + mag(phase.R(Yi)->source())
                          + mag(fvModels.source(rho, Y[i])->source())
                        )
                       /((Yrefi*alphaY)*(rho*mesh.V()))
                    );
                }
            }
        }

        if (foundY)
        {
            Info<< "    Composition = "
                << 1/(gMax(rDeltaTY.field()) + vSmall) << ", "
                << 1/(gMin(rDeltaTY.field()) + vSmall) << endl;

            rDeltaT.ref() = max(rDeltaT(), rDeltaTY);
        }
        else
        {
            IOWarningIn(args.executable().c_str(), Yref)
                << "Cannot find any active species in Yref " << Yref
                << endl;
        }
    }


    // Update the boundary values of the reciprocal time-step
    rDeltaT.correctBoundaryConditions();

    // Spatially smooth the time scale field
    if (rDeltaTSmoothingCoeff < 1)
    {
        fvc::smooth(rDeltaT, rDeltaTSmoothingCoeff);
    }

    // Limit rate of change of time scale
    // - reduce as much as required
    // - only increase at a fraction of old time scale
    if
    (
        rDeltaTDampingCoeff < 1
     && runTime.timeIndex() > runTime.startTimeIndex() + 1
    )
    {
        rDeltaT = max
        (
            rDeltaT,
            (scalar(1) - rDeltaTDampingCoeff)*rDeltaT0
        );
    }

    // Update the boundary values of the reciprocal time-step
    rDeltaT.correctBoundaryConditions();

    Info<< "    Overall     = "
        << 1/gMax(rDeltaT.primitiveField())
        << ", " << 1/gMin(rDeltaT.primitiveField()) << nl << endl;

}