## 5 Case Study: CV Joint Replacement in Korean Automotive Market  
### Estimating the Demand of CV Joint Replacement  
The case study of CV joint replacement in Korea is presented to evaluate the environmental and economic impact. A CV joint is one of the remanufacturable automotive parts, and the remanufacturing industry for CV joints is relatively well established in Korea. Although it has a long life cycle and replacements occur infrequently, it is still valuable to evaluate the environmental and economic impacts of CV joint remanufacturing due to their significance. The results can be used to determine how much financial support should be provided to expand the remanufacturing industry in Korea. For this case study, it is assumed that the exact annual sales data for a D-segment vehicle (Sonata) from 1992 to  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Description** & **New Parts** & **Remanufactured Parts** & **Unit** \\ \hline Retail price & \(P_{N}\) & \(P_{R}\) & USD \\ Cost & \(C_{N}\) & \(C_{R}\) & USD \\ Profit & \(\pi_{N}\) & \(\pi_{R}\) & USD \\ Replacement preference & \((T<T_{S})\) & \(\alpha_{1}=100-\beta_{1}\) & \(\beta_{1}\) & \% \\ Replacement preference & \(\alpha_{2}=100-\beta_{1}\) & \(\beta_{2}\) & \% \\ \((T>T_{S})\) & & \(\gamma\) & \% \\ Replacement probability & & \(\gamma\) & \% \\ \hline \hline \end{tabular}
\end{table}
Table 2: Parameters to calculate the profit of automotive parts replacement.  
2013 is provided [27]. The D-segment is popular in Korea, making its sales data a suitable reference for estimating the demand for CV joint replacement. The following assumptions are introduced to estimate CV joint replacements for each year.  
According to the maintenance manual, CV joints are recommended to be inspected every 10,000 km [25]. This inspection period aligns with that for engine oil changes. Visual inspections can be performed when vehicles are lifted, and this is usually the only opportunity to check for damage to the underside of the vehicle. Therefore, the inspection period (LP) for CV joints is assumed to be 10,000 km in this study. Since CV joints are not replaced after every inspection, the replacement probability (\(\gamma\)) must be considered. It is assumed that the replacement probability is 3%, as damage to CV joints is uncommon except for vehicles that are driven on rough or dirt roads.  
Surveys [28; 29] indicate that vehicle owners have different preferences when replacing CV joints. Most owners of older vehicles tend to spend less on maintenance, preferring remanufactured CV joints. The preference for new CV joints is denoted as alpha (\(\alpha\)), and the preference for remanufactured CV joints is denoted as beta (\(\beta\)). The sum of these preferences must equal 100%.  
The standard age distinguishing new from old vehicles is assumed to be seven years, as noted in [30]. According to this source, 90% of owners with newer vehicles prefer new CV joints due to their perceived reliability, despite the higher cost, while 10% prefer remanufactured ones. Conversely, 90% of owners with older vehicles prefer remanufactured CV joints, as the cost of parts becomes more important than reliability for older vehicles. The estimated annual demand for CV joint replacement is shown in Figure 3, which illustrates that while demand fluctuates, the changes are less significant than the fluctuations in vehicle sales.