I’m planning to buy a Hyundai Creta, but I’m confused whether to go for the 1.5 diesel or the 1.5 petrol. My daily commute will be short and things like fuel prices, other costs, or even the diesel car ban after 10 years in Delhi-NCR will not be an issue. I’m a huge fan of Hyundai’s CRDi technology, but I’m worried about DPF choking issues. Is there a maximum travel distance or time cutoff in a single drive to avoid DPF choking and also while at standstill with the engine idling? Does it come with a DPF heater or is there some kind of automatic regeneration? Will it show any percentage of how much the DPF is filled with soot?
Vinod Chawla, Delhi
As you are rightly aware, choking of the diesel particulate filter (DPF) is a big concern with modern-day diesel engines using said technology to meet BS6 emission standards. The DPF usually undergoes a ‘spontaneous regeneration’ if the exhaust temperature is anywhere between 400-600deg C while the car is running. However, a vehicle ideally requires sustained speeds in excess of 60kph for 20-30 minutes to be able to achieve these temperatures. Frequent short trips (less than 5km) or engine idling at low revs are unlikely to allow the vehicle to meet these conditions.
If spontaneous regeneration does not occur, the ECU will attempt a ‘dynamic regeneration’ after around every 300km so that the DPF is devoid of any accumulation of particulate matter beyond its storage capacity.
In this case, a DPF warning light will constantly glow on the instrument cluster, advising the driver to run the car in excess of 60kph for around 30 minutes, ideally on a highway, until the process is completed and the light goes off.
If your primary running is going to be limited to the city, and if even dynamic regeneration looks impossible on a regular basis, the only option available would be a ‘service/active regeneration’. Here, the DPF warning light will start blinking or the check engine light will glow continuously, after which the vehicle must be taken to the service centre at the earliest.
An OBD scan tool will be connected to fetch the soot accumulation percentage data from the differential pressure sensor to determine the clogging status of the DPF and the oxygen sensor. Then, the service regeneration can be initiated, during which a predefined quantity of extra fuel is added into the cylinders in the form of post-injection pulses to increase the exhaust gas temperature and allow for the DPF regeneration to complete by idling the engine at high RPMs.
These are the different ways in which the DPF can be ensured to remain healthy and provide niggle-free engine functioning. To the best of our knowledge, the 1.5-litre CRDi engine in the Hyundai Creta doesn’t deploy a DPF heater. Therefore, if DPF regeneration is not accomplished on a regular basis while driving, eventually, the filter will malfunction after getting completely clogged and the engine would show symptoms of poor performance and feel sluggish, leading to the only solution of ultimately getting the filter replaced, which could be an expensive affair.
While the reduced amount of sulphur in BS6 diesel fuel prolongs the clogging of the DPF, the regeneration process is still an inherent part of the operation of a DPF-equipped engine that would be attempted every time the car is driven.
Hence, taking all of this into consideration, as well as the strict 60kph speed limit on most roads in Delhi, we would advise thinking this through in detail and making the right purchase decision in terms of the engine option on the new Creta. If not the diesel, you could also opt for the equally fun to-drive 1.4-litre T-GDI motor or the reasonably performing 1.5-litre petrol.