True or False: IDI combustion chambers use lesser compression ratios to compensate for lower thermal efficiency.

The statement is false. Indirect Injection (IDI) combustion chambers typically do not use lesser compression ratios to compensate for lower thermal efficiency. In fact, IDI engines often operate at a higher compression ratio compared to their direct injection counterparts, which can help enhance combustion efficiency and improve performance.

The design of IDI combustion chambers allows for a more controlled ignition process, utilizing lower temperatures and reduced emissions. However, this does not necessitate a reduction in compression ratio, as higher ratios are beneficial for extracting more energy from the fuel.

Moreover, varying factors such as the specific design of the engine, fuel type, and overall engine management systems play significant roles in determining the optimal compression ratio for achieving desired performance, fuel efficiency, and emissions control. Hence, the relationship between compression ratios and thermal efficiency in IDI engines is more complex than the statement suggests.