Infrared imaging was used to study the impact Of a Sudden decrease in the exhaust temperature on the spatiotemporal temperature of a single layer planar diesel particulate filter (DPF). The experiments revealed that a sudden decrease in the feed temperature by 100 degrees C can lead to sudden temperature rise (wrong-way behavior) of about 50 degrees C above that obtained with the constant original temperature. The transient temperature rise highly depended on the position where the temperature shift was initiated, that is, the time that the moving temperature front stayed in the DPF before exiting it. The temperature excursion near the end of DPF was much higher than the temperature rise in middle or near the entrance. The experiments reveal that the DPF temperature during dynamic operation can exceed in a counterintuitive fashion that obtained Under stationary (constant) operating conditions. This suggests that the reported melting of cordierite DPF may have been caused by rapid changes in the feed conditions due to a change in the driving mode, Such as a sudden vehicle deceleration.