Diesel Engine Emissions Primer PowerPoint Presentation, PPT - DocSlides

Diesel Engine Emissions Primer

Everything you need to know about why the world’s largest auto OEM (in 2015) will drop to # 3 in 2016

ASE-IEA PRESENTATION

JULY 26, 2016 Concord, NC

Sean Bennett

Cengage Learning

Perfect Combustion of Diesel

H is oxidized to form H

2

O

HC (fuel) is reacted with air

Carbon is oxidized to form CO2

Nitrogen remains unaffected by combustion reaction in cylinder

‘Perfect’ combustion seldom occurs …

… stoichiometry is generally unachievable in lean burn diesel engine cylinders

… in modern low emission diesels, cylinder temperatures have to be precisely managed

Combustion mixture rich or temperatures low:

Carbon component of the HC fuel is not properly oxidized in the cylinder…

… resulting in:

CO

VOCs (vaporized HC)

PM

Combustion mixture lean or temps too high:

… nitrogen ceases to be inert and is oxidized to form various compounds of nitrogen which we know as NOx

…

NOx

is gaseous … therefore not observable to the eye

PHOTOCHEMICAL SMOG

NOx and HC are primary constituents of photochemical smog

NO

2

is key to the formation of ozone and acid rain

How photochemical smog forms

HC (in liquid, solid, or gaseous states)

+

NOx

+

Sunlight

+

Time

=

Photochemical smog

Perfect conditions for photochemical smog formation:

LA … 2

nd

largest conurbation in NA

Abundant year-round sunshine

Per capita auto ownership is highest in the world

Ports of LA and Long Beach are diesel intense zones: shipping, drayage, trucking

San Gabriel mountains stall and wall in emissions

GHGs

Water vapor

Methane

Ozone

C02

CO2

2007: Massachusetts versus Supreme Court produced a ruling that CO2 was not just a GHG but also a pollutant

The ruling resulted in the current Administrations drive to set CO2 dump to a set of standards to begin implementation in 2017

Combusting 1 gallon of diesel fuel produces 22

lbs

of CO2

NEW TECHNOLOGY

DIESEL ENGINE (NTDE)

NTDE term was coined by Health Effects Institute

NTDEs are defined by HEI as diesels meeting EPA 2010 or later standards

HEI NTDE effects testing was undertaken on rats

Tests suggest that no animal respiratory or organic damage was sustained by animals after long term exposure to NTDE exhaust

EPA 2010 Standards and History

NTDE Features

Precise management of combustion

Exhaust gas recirculation (EGR)

Diesel oxidation catalysts (DOCs) (catalytic afterburning)

Diesel particulate filters (DPFs)

Selective catalytic reduction (SCR)

EGR

Exhaust discharge is the most convenient source of ‘dead’ (unreactive) gas

It dilutes the intake charge (of oxygen) and lowers combustion temperatures

It can be cooled and may be ‘cleaned’ (Cat CGI) sourced downstream DPF

EGR cut-percentage is ECM controlled

DOC

Diesel oxidation catalyst

Uses platinum and palladium catalysts

Used for a generation in diesel engines and is located upstream from DPF

Reaction temps range from 800-1000 C

SCR

NOx reduction agent used in gasoline fueled engines (rhodium) only functions as a catalyst when stoichiometry is <15:1

SCR uses ECM-managed DEF (aqueous urea) injection to reduce NOx compounds back to elemental O2 and N2

DEF is a consumable that must be replenished: levels are ECM-monitored and are EPA-required to progressively cripple the engine if refill alerts are ignored

SCR operation

DPF

A soot trap for emission solids known as

particulate matter (PM)

PM is entrapped by filters and collected

When soot reaches a threshold value, the DPF must be

regenerated

Regen reduces soot to unreactive ash

DPF Entrapment Principle

DPF regeneration modes

Passive

: set to occur when soot build-up has reached a threshold and engine exhaust temps are high enough

Engine is usually under load and the vehicle is running at highway speeds

Exhaust gas heat (600 C plus) is used to burn-off soot to unreactive ash

Ash is then collected

DPF regeneration modes

Active:

occurs when DPF soot levels exceed a threshold value

ECM-controlled when vehicle operating conditions permit

Or ECM-diagnostic software generated

May require fuel to be injected into the exhaust gas and spark-assist ignition

DPF Maintenance

Regeneration results in ash residues: ash build-up requires DPF to be cleaned using specialized equipment.

Federal law requires this to be no more frequent than once a year or 150,000 miles during ‘normal’ operation of the vehicle.

The minimum mileage thresholds are set to increase for MY 2017

Aftertreatment

status alerts

Heading toward 2017 and 2018: the “Freight Efficient” truck

Emissions Tampering

Current EPA penalty for ANY tampering with a diesel emission control device or programming is

$37,500

PER infraction

Attempting to bring a vehicle back into compliance that fails:

Fine $$$

Servicing vehicle engine and ignoring a CEL or HD-OBD alert:

Fine $$$

NO STATUTE OF LIMITATIONS!

Every vehicle from 1989 to current MY is covered

Every facility servicing commercial diesel engines should have a clearly stated shop policy for handling any emissions-related problem

Shops and technicians are liable!!!

VW and the damage done to the optics of owning any diesel engine – and to the environment

VW had 70% of the light vehicle diesel market from 2010 to Oct 2015

Within those years VW sold 490,000 non-compliant engines in the U.S.

The company sold another 10 million ‘non-compliant’ diesels worldwide.

How were they caught???

PEM (portable emissions measurement) tests at the West Virginia University’s Center for Alternative Fuels, Engines and Emissions (CAFEE) detected up to 35 times the permitted NOx dump in VW TDI engines - ALL of which easily passed CARB and EPA tests.

CAFEE reported their findings to CARB and EPA: PEM testing confirmed CAFEE

How did VW Fool CARB/EPA

VW had Bosch write an algorithm for TDI ECMs that detected CARB-EPA test drive cycles (absence of steering input and TPS angle inputs) – during which lean burn operation was disabled using the defeat programming

When non-test operation was detected, lean burn was activated increasing power and fuel economy – and NOx dump!

Consequences

Some math: $37,500 X 490,000 =

+

$18 B

VW have settled with EPA for

+

$13 B – good deal?

Next comes individual states lead by NY for criminal ‘damage to the environment

VW, Audi and Porsche diesel sales ban

Discussion

Thanks

Sean Bennett Cengage Learning

email@seanbennett.org