# Development of a Hybrid Electric Vehicle Simulation Tool with a Rule-Based Topology
## 1 Introduction  
The hybridization of the powertrain represents an important milestone on the way to CO\({}_{2}\)-neutral mobility. Nearly all automobile manufacturers have several hybrid concepts in their portfolio. However, the requirements of emissions legislation vary strongly worldwide. In addition, costs, complexity, driving performance and vehicle platform are other important decision criteria for the choice of a suitable hybrid concept. In light of stringent CO\({}_{2}\) targets and long-term sustainability, hybrids are considered the most feasible solution in the short and medium term. Hybridization of the drivetrain has been implemented to varying degrees, from 48 V mild hybrids to strong hybrids and to plug-in hybrids, each with increasing degrees of electrification. The governments in various countries are encouraging the adoption of different degrees of electrified cars by mandating stringent emissions standards and providing various incentives and subsidies to buyers. In the United States, over 4 million pure battery electric vehicles (BEVs) and full hybrid electric vehicles (HEVs) were sold in 2016 [1]. In Europe recently, the rate of growth in the sales of HEVs has also increased, and the main market is for full hybrids followed by plug-in hybrids. The highest sales of hybrid electric vehicles in Japan are in the full hybrid segment, followed by the mild hybrid. Japanese automakers Toyota and Honda are increasing their commitment to producing more hybrid models to meet environmental and fuel security goals. Growth in China's electric vehicle industry has expanded at an astonishing rate, and the country now has the largest number of BEVs on the road. Within the global economic regions of China, Europe, North America, Japan and Korea, whichtoday account for 86% of the global automotive sales market, China significantly leads in the sale of BEVs. In the future, HEVs and BEVs will continue to dominate the car market, and Japan will no longer be the main market, as growth is expected from Europe and China. The 48 V mild hybrids will be popular in the short term as Audi, VW and many others have adopted them to improve fuel economy. By 2025, approximately one in five new vehicles across the world will be equipped with a 48-Volt drive. Full HEVs will avoid the large trade-off between power and efficiency of pure internal combustion engine (ICE) cars, leading to broader consumer acceptance. Most automakers are planning to produce full HEVs on a large scale. Toyota will continue to rule in the full HEV segment for the foreseeable future. The growth of plug-in HEVs (PHEVs) and BEVs drastically increased from 2016 to 2017, with 73% in China, 39% in Europe, and 27% in the USA. This trend will continue to increase, and the expected sales of PHEVs and BEVs will be more than 2 million in China by 2020. A scenario from another research team, called the \"European original equipment manufacturer (OEM) Scenario\", representing an average value scenario of the European OEMs, was published on the future of powertrain technologies in the new vehicle fleet [2]. BEVs will continuously increase. Their market share will reach approximately 27% in 2035. Plug-in hybrids will maintain their market share constantly at around 10%. In consequence, vehicles that can be externally charged will account for approximately 37% of the overall powertrain share in Europe by 2035. The positive effect of PHEVs regarding CO\({}_{2}\) emission reduction potential rests to a great extent upon the current worldwide harmonized light vehicles test cycle (WLTC) test procedure [3; 4]. This takes into account the charge depleting and the charge sustain mode. The first defines the CO\({}_{2}\) emissions and fuel consumption in that mode, as well as the theoretical electric range. The utility factor can be deduced by the latter. CO\({}_{2}\) emission in charge depletion, utility factor, plus CO\({}_{2}\) emission in charge sustain mode lead to the weighted CO\({}_{2}\) emission relevant for certification.