WHAT IS TIER 4 FINAL?
Tier 4 Final refers to a set of emissions requirements established by the government (EPA or Environment Canada) to reduce emissions of particulate matter (PM), oxides of nitrogen (NOx) and air toxics from new, non-road diesel engines.
How Do Our Engine Manufactures Meet Tier 4 Final Requirments?
Each of our engine manufacturers has chosen to meet Tier 4 emission standards using a variety of different methods. Below are various methods engines may use to meet emission guidelines, followed with details on how Isuzu, Hatz, JCB and Yanmar have chosen to meet those standards.
Electronic Control Systems
The most important characteristic of Tier 4 compliant engines are the Electronic Control Systems
Common Rail Fuel Injection System
- High pressure fuel is stored in the common rail, and the injection system is electronically controlled
- Common rail system to allow fine-tuned electronic control of fuel injection
- Benefit: improved fuel control & improved combustion = reduced emissions, quieter, and improved fuel efficiency.
Cooled EGR (Exhaust Gas Recirculation) System
- Recirculates some exhaust gas into the air intake
- gas is cooled by the EGR cooler (reducing the combustion temperature)
- Reduces emissions
ECU – Engine Control Unit
- The brain of the engine. It electronically controls all of the systems above.
Exhaust After-treatment Systems
The next critical component of the system to meet T4F is an Exhaust After-treatment System. Tier 4-Final regulations demand huge reductions in PM (particulate matter) and NOx. To meet this most engines will utilize one or both of the following systems (JCB is an exception; they offer a 74HP engine with no exhaust after-treatment)
Diesel oxidation catalyst (DOC)
- The DOC is a no-maintenance flow through filter that contains precious metals that serves to reduce certain pollutants and, when required, to raise exhaust temperatures. The DOC converts carbon monoxide to carbon dioxide and converts hydrocarbons to carbon dioxide and water.
- DOC is a no-maintenance; pass through system. It is essentially a muffler-filter containing ceramic and precious metals. There is no Regeneration with this system.
Diesel particulate filter (DPF)
- The DPF is a filter that traps any remaining soot that the DOC couldn’t oxidize. The soot or particulate matter (PM) remains in the DPF until it is regenerated either passively or actively. Trapped particles on the DPF filter element are oxidized (burned up) through a continuous cleaning process called regeneration. Passive regeneration occurs when the normal operating temperatures and the DPF will oxidize the particulates anywhere between 275-360⁰ Celsius.
- The heat of the exhaust burns away most of these particles but when that isn’t sufficient, additional heat can be generated in a process known as active regeneration. Active regeneration is instigated when sensors detect an excessive build-up of particulates within the DPF. Raw fuel is injected into the exhaust stream to trigger temperatures over 600⁰ Celsius is required oxidize the build-up of soot.
- DPF system works in conjunction with a DOC and a SF (soot filter) to make up the DPF. The DPF portion of the system is closely monitored through sensors that relay information back to the ECU to ensure it is functioning properly. Monitor: Air flow, pressure and temperature sensors
Sizing Your Engine: Light Loads; Low Duty Cycle; Cold Temperatures
- It is more important than ever to properly size your engine to your application
- You must avoid light load situations for prolonged periods; especially during cold tempatures.
- You cannot idle a T4F engine for long periods without impacting the DPF and DOC systems.
- Cold temperatures and long idle times increase DPF regeneration frequency
- Engine Load and Speed are monitored and critical
Available Engine Options:
ISUZU SOLUTION: L-Series and J-Series (48HP to 72HP)
- Direct injection, Common rail system, Cooled EGR
- Diesel Oxidation Catalyst (DOC)
HATZ SOLUTION: H-Series (48HP to 74HP)
- Direct injection, Common rail system, Cooled EGR
- Diesel Oxidation Catalyst (DOC)
JCB SOLUTION: Eco-Max Series (74HP)
- Direct injection, Common rail system, Cooled EGR
- No Exhaust After-Treatment. No DPF! No DOC!
YANMAR SOLUTION: TNV Common Rail Series (24HP to 74HP)
- Direct injection, Common rail system, Cooled EGR
- Diesel Particulate Filter (DPF)
Yanmar has 2 DPF solutions over 25 hp.
- Engines with Exhaust Throttles for light
duty/low load patterns.
- If you have exhaust (DOC) temps that consistently are less than 250C, this model must be considered.
- Engines without Exhaust Throttles for mid/high load usage.
Yanmar Regeneration (DPF only)
PM (soot) will accumulate in the filter. Regeneration is required to burn off the PM.
Passive Regeneration
- Passive regen happens ‘behind the scene’ and is not noticeable. If the engine operating temperature is within acceptable parameters regeneration will occur automatically.
- When Passive Regeneration is occurring, the engine sound may change a little, however performance/output/engine speed does not change.
Stationary Regeneration
- Emergency Stationary (Active) regen will occur when sensors detect excessive build-up in the DPF.
- When performing a Stationary Regeneration, you must stop operation. However Stationary Regeneration doesn’t usually happen, it is only for emergency purposes.
- The YANMAR Regeneration system has the option to inhibit regeneration. If you select this mode, Regeneration doesn’t occur suddenly, allowing you to work in areas where there might otherwise be a hazard.
- Sequence of Events- Stationary Mode:
- Control Panel issues warning every 15 minutes when the engine is in a stationary standby mode
- There is no limit to the number of times that you can inhibit regeneration, however after 10 hours (or if soot load gets too high) the engine will enter backup/limp home mode and need to perform a recovery (3 hour) regeneration.
- The other item to note that while in stationary standby mode you are limited to 85% power the first 2 hours and then down to 50% power for the next 8 until you enter limp home mode.
- Once in ‘Limp Mode’ the operator must perform a ‘recovery regen’ (3 hours)
- NOTE: Yanmar 3TNV88C and 4TNV88C Emergency Regeneration Speed is 2200RPM. This means your application must be able to operate up to 2200RPM.
Why choose a Yanmar DPF over a DOC Only Engine?
- YANMAR DPFs will run maintenance free for 6000 hours.
- Tier 5 will eventually happen in Canada and the USA. To meet Tier 5 all engines will require a DPF. A DOC only engine will not meet the PM limits without adding a DPF.
- Euro Stage 5 starts 2019; all of their new models require a DPF.
What is the difference between YANMAR’s DPF and other DPF’s?
- YANMAR uses only pressure and temperature sensors for gas flow calculation which is more robust.
- Other manufacturer’s use a mass air flow sensor which can be inaccurate over time.
What is the advantage of YANMAR’s DPF?
- Less Regeneration Time at low loads. Engines typically do not operate at peak power. Most applications spend the majority of the time at operation loads between 30-50%.
- YANMAR outperforms the competition in these areas.
Yanmar Control Panel
- In order to address the challenge of making a DPF engine easy for operator use, Yanmar has developed its own low cost Control Panel for Final Tier 4 Engines.
The engine control panel is programmed to account for engine DPF Regeneration.