[sagarpadaki]

Originally Posted by SS-Traveller

Will someone look into the legalities of why vehicles of a particular manufacturer refuse to pass simple emission tests despite being certified as BS-IV? Will someone... oh, never mind.

Can you throw some light onto this?! I am mighty eager to know which manufacturer and vehicle(s) do it!

[SS-Traveller]

Originally Posted by sagarpadaki

Can you throw some light onto this?! I am mighty eager to know which manufacturer and vehicle(s) do it!

Er... I think there's just the one manufacturer mentioned by the OP of this thread...

[humyum]

I got my PUC done, around a month back. Simple probe into the exhaust pipe and readings in 30 seconds, 120 bucks and a certificate for 6 months

If someone plans to rev my diesel swift to the redline 12 to 15 times I will break his teeth. Heck in the Srinagar - Kargil road when the swift was not climbing on many inclines like the Zozila pass, it pained me to no extent to rev her till 4 thousand plus rpm and I am not going to let someone do it in Mumbai when I can get away with a simple method to get the certificate.

[CANPUSH]

Yes. When I owned a Palio D (for good 7 years) every time to get PUC I had to undergo this exercise.

In fact for the first time when I went for PUC and the guy asked me to floor the throttle I just did it with a bang and huge cloud of black smoke emerged out of tail pipe. The guy just told me to go to service station straight as my car would never pass the test unless engine is tuned. Actually, I had just got the car back from service after completion of one year and engine was tuned and oil was replaced at that service.

When I talked to my friend (a diesel veteran and ex Tata motors employee) about it. He laughed a lot and advised me never to floor throttle of diesel engine with no load. Even a new diesel engine can not pass the test that way. He also advised me never to go to PUC with cold engine. You must drive for 8-10 kms and get the engine hot when you go for PUC.

The trick is to lightly press the throttle till you reach desired RPM (3000) and your car can easily pass the test.

Towards the end of my ownership three years ago I did came across one PUC machine where number of probes inserted at places were less. However, still I had to raise the throttle and the print out was nice 20 centimeters long with number of readings as usual.

I trust that is the usual method of checking pollution of diesel vehicles. Now I own a petrol head so no idea if the method or machines have changed over last three years.

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[anujmishra]

Yesterday evening, I went to another pump and they actually checked the pollution of my car properly. He did not put anything in oil chamber and having some machine to read the RPM/Temp inside car. He raced engine between 1980 to 2320 RPM and got 5 readings, it is printed in my report. temperature readings were ~75 degrees. This is another HP pump near Phoenix Mall on Whitefield Road. This guy is well trained and I got my PUC from this pump before. Also, it looks their equipment is calibrated, atleast for my car .

Subsequently, my car passed PUC and got SMS. Compared to other pump, which I visited morning, that guy was revving SUMO Grande close to 5000 RPM. So, there is gentle method available to get the PUC.

Another question is, If vehicle is certified as Euro IV then why all this circus? If we have to do all these things, then what is the meaning of Euro IV or any Euro?

[sgiitk]

Actually it makes sense. In a diesel engine the inlet valve is always fully open during intake stroke, so the power etc. are controlled by the amount of fuel injected which is the maximum at full throttle, hence possibly the most polluting.

[sukiwa]

If flooring of throttle is must for PUC of Diesel vehicle, it would be better that engine has reached its optimum temperature.

Originally Posted by CANPUSH

Towards the end of my ownership three years ago I did came across one PUC machine where number of probes inserted at places were less.

Do you remember this PUC station?

[CANPUSH]

Originally Posted by sukiwa

If flooring of throttle is must for PUC of Diesel vehicle, it would be better that engine has reached its optimum temperature.



Do you remember this PUC station?

@Sukiwa, I am sorry I do not remember where I did it. It was way back in September 2009.

I trust, now most of the stations have modern equipment to test Euro IV engines.

[anujmishra]

Originally Posted by sgiitk

Actually it makes sense. In a diesel engine the inlet valve is always fully open during intake stroke, so the power etc. are controlled by the amount of fuel injected which is the maximum at full throttle, hence possibly the most polluting.

But sir, do we need to raise full throttle in diesel anytime on normal use? Diesel engine work fine between 2000 - 3000 RPM perfectly in modern cars.

[sirius1845]

Hi,

The reason for giving full throttle is to flush out soot deposit in the exhaust system if vehicle has been driven smoothly for prolonged time. Occasionally the vehicle has to be driven at high speeds and at good acceleration . Pls see the catalytic converter care procedure given in the owner's manual.(Page 141)

"Maintenance of Catalytic ConverterCatalytic Converter should be flushed by giving full throttle(4 to 5 times) in standing condition of vehicle on daily basis.In addition to this it is recommended to run the vehicle athigh speeds (80 to 100 kmph) for few km as this will help toflush the carbon soot deposits from exhaust system andcatalytic converter. High speed running of the vehicle maybe done periodically to avoid chocking of catalytic converter."

[srishiva]

The authorities should take a random vehicle and see if they pass the tests when new. The whole thing smells rotten. Even for people who would like to have a good vehicle meeting the norms, it appears difficult to get the actual readings.

Even in developed countries, vehicles do emit more than required amount of pollutants under load (especially CO2). No wonder we have various circus tricks around in our country.

[SnakemanJohny]

Let me try to clear some confusions, even though I do not own a diesel vehicle.
According to Central Motor Vehicle Rule #115 (plus #116, as these two deal with auto-emissions), diesel engine emissions after 2004 are supposed to be tested with the 'no load, free acceleration method'.

It says that "The free acceleration test shall be carried out... with the vehicle engine warmed up to attain an oil temperature of minimum 60 Centigrade. During each free acceleration, maximum no-load speed shall be in the bandwidth of +/- 500rpm for three wheeler vehicles and +/- 300rpm for all other categories of vehicles. The free acceleration test shall be repeated till the peak smoke density values recorded in four successive accelerations meeting the above no-load criteria are situated within a bandwidth of 25% of the arithmetic mean" etc. "The smoke density recorded will be the arithmetic mean of these four readings. In case the valid readings are not obtained within ten free accelerations, or the smoke density obtained are not within the limits, the testing shall be discontinued, and the vehicle owner shall be advised to resubmit the vehicle after repair/service "

So if the PUC 'tester' is revving your car very hard during the test, he/she may be either trying to bring your oil temperature up, or doing the 'free acceleration test', though the latter does not require full throttle. Neither does the former, if you drive for some distance before appearing for the test. The you can try to read the oil temp. displayed on his monitor, and ask him not to do 'flooring'.

The battery connections are needed for the oil temp and RPM readings, and please do not believe anyone saying that they can get the emission readings from there, instead of from a probe at the tailpipe. Do observe carefully that a) they replace the insulating cap over the positive terminal of the battery after disconnecting their leads, and b) that they replace the dipstick in the oil tank. Pump attendants may neglect to do both in a hurry. The former may result in short-circuit and fire in case the bonnet is dented from the top, and the latter may result in loss of some engine oil and the dipstick.

The permissible limits for both naturally aspirated and turbo-charged diesel vehicles are (a) Light Absorption Coefficient - 2.45, and Hartridge Smoke Density (HSU) Units- 65.

[YVES]

Any place in Whitefield/Mahevpura/Marathahalli in Bangalore were PUC is done without revving the Engine to redline

[rahulba]

Yesterday I went to get the PUC done for my Figo TDCi and it failed. To do the PUC check, attendant at the test center (Next to Hari Nagar Bus Depot) revved the accelerator to maximum (4.5K RPM approx.) and car emitted huge amount of soot. I was to see this as 60K servicing (done couple of days before) included replacement of air filter, diesel filter and oil change etc. among other things. After this I consulted few of the BHPians offline who suggested following:

1. Revving the engine hard for 2-3 Kms. should clear up the EGR valves and black smoke would go away. This also keeps the engine healthy in long term.
2. Attendants at petrol pump just accelerate freely and that is not required for Diesel vehicles. Ask the attendant to test it at low RPM say something around 3K and that should be enough for the test.

Called up the Ford service center where servicing was done and they also mentioned that testing at 4.5K RPM is wrong.

With this information at hand, I revved the car at 3K RPM constantly for 2-3 Kms before heading to the same test center next morning. Discussed the point 2 with attendant and he agreed to do the test at low RPMs (though he kept on insisting that Govt. wants them to accelerate freely as per written document). I also told him to make sure that RPM doesn't go above 3.5K this time. He then plugged all the equipment's (except for pipe in exhaust) and started testing to make sure readings are showing within prescribed limit in his handheld equipment (please note that readings do not feed the system unless pipe from exhaust is plugged to the machine connected with desktop at PUC center). And once the readings were showing fine, he plugged the pipe into the exhaust, revved till 4K RPM and BINGO! Test result was successful and result showed the maximum RPM reached (out of 4 readings) was 4300 approximately (although Tacho reading didn’t go above 4K somehow). He then printed the Pass certificate and I came home happily knowing that I am not over polluting the world’s most polluted city.

Fees paid: 110/-

Thanks to the fellow BHPians Khoj, Akshay4587, sameerg001 and Deeps for their advice on the issue.

[shibujp]

Went to get the PUC certifcate for my Polo GT and was in for a surprise as the procedure has been changed.

My first surprise was when the technician asked me to park the car facing the camera rather than reversing into the slot as was normal procedure.

With the engine running, she then asked me to open the car's bonnet and proceeded to connect two leads to the battery.



Then she asked me to rev the engine at least 5 time.

After this she put the exhaust emission measuring pipe into the exhaust and asked me to rev the engine around 3 time. In between the revs readings were taken.

Here are the final readings.



Looks like the government is serious about diesel emissions. Is it the end of the road for torque monsters? Is purchasing diesel cars gonna be a wise decision in the future?

Drive on,
Shibu.