A wide set of nitrogen compounds, Mannich amines, polyalkenyl succinimides, polyalkylene carbamates are patented by Shell Oil Co.
Deposit control agents in the combustion chamber are compounds with high temperature stability, mainly succinimide derivatives [3, 4].
On the other hand, the spectrum of the deposit features a signal at 1654 [cm.sup.-1], which can probably be attributed to an amide group resulting from the opening of the succinimide ring 6.
The spectra show details of the characteristic peak pattern of the compound polyisobutylene succinimide (PIBSI; figure 8).
Mass signals of the succinimide (SI) part7 ([C.sub.4][H.sub.2]N[O.sup.-.sub.2]) exhibit distinctly lower signal intensities in the spectra of the deposit.
* In the investigated deposits from different diesel engine parts--especially on needle valves--compounds based on polyisobutylene succinimide (PIBSI) structures are identified among others.