In order to reduce the emissions of polluting gases and contribute to the efficient use of energy, natural gas has gained relevance due to its cleaner burning when compared to gasoline and diesel oil. In this work, a zero-dimensional thermodynamic model was developed to predict the performance, for the entire operating conditions, of a 11.7-L, six-cylinder, turbocharged spark-ignition engine used as genset and running on natural gas. This zero-dimensional model covers the closed period of the engine operating cycle. Firstly, this engine was tested in seven (7) different operating conditions to obtain the mass fraction burned and the pressure curves inside the cylinder. The combustion process was modeled using the simple Wiebe function, whose parameters were obtained from the seven (7) curves of the mass fraction burned through the Levenberg–Marquardt optimization method. Correlations were developed to estimate the Wiebe function parameters, as a function of pressure and temperature in the intake manifold, cylinder wall temperature, power and fuel consumption, for the entire operating range. The combustion efficiencies were estimated from the seven (7) experimental pressure curves with the aforementioned optimization technique. Results showed that the differences between the Wiebe function parameters obtained with the developed correlation, for the whole engine operating range, were less than 3% when compared with the Wiebe function parameters estimated for each of the seven (7) operating conditions tested. Results also showed that the thermodynamic model can be used to simulate the engine’s performance, leading to errors less than 5% when compared with the measured maximum pressure and indicated mean pressure. In addition, it was found that the delay and duration of the combustion are smaller than those usually found in spark-ignition engines and that the energy release is deficient, resulting in high specific fuel consumption. This issue can be addressed by installing an equivalence ratio control system, especially in loads above 50%, thus ensuring greater control of emissions and increasing energy efficiency.

为了减少污染气体的排放并促进能源的有效利用，天然气与汽油和柴油相比具有更清洁的燃烧性，因此具有重要意义。在这项工作中，开发了一个零维热力学模型来预测在整个工况下用作发电机组并在天然气上运行的11.7升六缸涡轮增压火花点火式发动机的性能。零维模型涵盖了发动机工作循环的封闭期。首先，在七（7）个不同的工况下测试了该发动机，以获得燃烧的质量分数和气缸内的压力曲线。使用简单的Wiebe函数对燃烧过程进行建模，其参数是通过Levenberg-Marquardt优化方法从燃烧的质量分数的七（7）条曲线获得的。建立了相关性以估计Wiebe功能参数，该参数是整个工作范围内进气歧管中压力和温度，气缸壁温度，功率和燃料消耗的函数。使用上述优化技术从七（7）个实验压力曲线估算燃烧效率。结果表明，与针对所有七（7）个工况估计的Wiebe功能参数相比，在整个发动机工作范围内，通过发达的相关性获得的Wiebe功能参数之间的差异小于3％。结果还表明，热力学模型可用于模拟发动机性能，与测得的最大压力和指示的平均压力相比，误差小于5％。另外，发现燃烧的延迟和持续时间小于火花点火发动机中通常所见的延迟和持续时间，并且能量释放不足，导致高的单位燃料消耗。可通过安装等效率控制系统来解决此问题，尤其是在负载超过50％的情况下，从而确保更好地控制排放并提高能效。已经发现，燃烧的延迟和持续时间小于火花点火发动机中通常所见的延迟和持续时间，并且能量释放不足，导致高的单位燃料消耗。可通过安装等效率控制系统来解决此问题，尤其是在负载超过50％的情况下，从而确保更好地控制排放并提高能效。已经发现，燃烧的延迟和持续时间小于火花点火发动机中通常所见的延迟和持续时间，并且能量释放不足，导致高的单位燃料消耗。可通过安装等效率控制系统来解决此问题，尤其是在负载超过50％的情况下，从而确保更好地控制排放并提高能效。