Abstract
The THC emissions from a DI diesel engine during increasing loads significantly increased to very high concentrations from just after the start of the load increase until around the 10th cycle, rapidly decreased until the 20th cycle, and then gradually decreased to a steady state value after 1000 cycles. The increase in THC is more significant with lower compression ratios and lower coolant temperatures. The dominant components present in the THC transient spike were lower hydrocarbons with carbon numbers less than eight. In particular, ethylene showed a much higher concentration than the other components.
