Kukje vs Everybody

Read the article? See the video! Kukje vs Everybody - The Video

The Kukje engine featured in TYM’s T474, T494 and T574 is the best diesel engine available in ANY tractor from ANY manufacturer. I don’t say that nonchalantly, I intend to back that statement up.

First, let’s dive in to modern diesel engines and emissions systems. This is by no means a comprehensive review of all possibilities, but only the ones that apply to diesel tractors in the 40-59hp range.

Mechanical vs Common Rail Fuel Injection. Over the years various manufacturers have had lots of different takes on how to inject diesel fuel into a combustion chamber to make power. Here I will just discuss the two most common methods in modern tractors. Most mechanically fuel injected diesel engines have one high pressure fuel injection pump which compresses the fuel and sends it to each cylinder individually. This has been the most common way of making diesel engines work. Recently, in order to meet emissions criteria, tractor manufacturers have taken some of the technology from the automotive world and applied it to tractors via High Pressure Common Rail Fuel Injection. In this version of diesel technology, a single high pressure pump pressurizes the whole system and each injector is tied to this “common rail.” From there, electronically controlled injectors just “release” the high pressure fuel in to the cylinders. Common rail is great technology and offers a lot of benefits, but compared to mechanical systems and especially on tractors, it falls severely short. Here’s why… To make common rail work, you need an ECM, a high pressure fuel pump, multiple sensors along the way, electronic injectors and a wire harness that ties it all together. If ANY of the systems in the chain fail, the engine will be severely hindered if it will even run at all. That’s a lot of complex systems to pack into a tractor which is exposed to rain, mud, dirt and snow on a regular basis. It’s also a lot more complicated to troubleshoot and repair, and impossible to do without diagnostic software. On the other hand, mechanical fuel injection pump engines have been around in much the same form since the first diesel engines were built. Once your battery has started the engine, it will run without any electricity for as long as you have fuel. Modern mechanical engines do have some modern convenciences however, like low oil shutoffs which only serve to protect the engine and save you big money if you ever run low on oil. 

Those are the two basic "hearts" of a diesel engine, now on to the emissions.

EGR Valves function to return a portion of the engine exhaust back to the intake to “reburn” and help reduce emissions. EGR valves usually have EGR coolers which cool the hot exhaust air before it reaches the intake. The valves themselves are prone to carbon buildup, mechanical and electronic failure. EGR coolers can rot out or leak internally which can send coolant into the engine. This presents as a phantom coolant leak, you’re loosing coolant regularly but it’s not leaking anywhere you can see. The question then becomes is it going straight into the engine via a cracked head or bad head gasket? Or is it merely a faulty EGR cooler? All you can do is pray you have a competent mechanic who will know how to identify the proper repair and won’t replace your head gasket when all you needed was an EGR cooler.  

DOC, DPF and DEF

DOC - Diesel Oxidation Catalyst

DPF - Diesel Particulate Filter

DEF - Diesel Exhaust Fluid

Let’s start with DEF even though it doesn’t usually apply to anything under 75hp. DEF systems are always secondary to DPF systems and always come after the DOC and DPF. They inject a urea solution into the passing exhaust gasses which lowers NOX emissions. DEF systems themselves are rather complicated because they involve DEF tanks, pumps, DEF injectors, NoX sensors and heaters. DEF can turn into a slush in cold temperatures so it needs to be kept warm in cold weather. This further complicates the systems because they need to either have electrical heaters or heat exchangers which run on hot engine coolant. Luckily, DEF headaches won’t bother most compact or utility tractor owners.

On to DOC and DPF. Both are supposed to reduce particulate emissions from diesel engines. DOC’s are very similar to a car’s catalytic converter. They don’t do much and go un-noticed until they plug up and need to be replaced. DOC’s do not regen while DPF’s need to regen. Let's talk about what a regen is… Regen is short for regeneration and this is the process of cleaning soot out of a DPF. The way it works is the engine runs at a high rpm (usually around 2000 for tractors) and once everything is at the correct temperature an additional injector mounted between the exhaust manifold and the DPF injects diesel directly into the exhaust system. This creates a lot of heat and pressure which cleans out the DPF. Regen’s need to be performed when the onboard systems detect the filter is getting full. Compared to DEF systems DPF’s are rather basic. A differential pressure sensor tells the computer when the filter is full, temperature sensors monitor the system to make sure nothing overheats and the additional injector sends diesel until the system is cleaned out.

Now that we know the basics of emissions control systems applicable to tractors, lets talk about how they are implemented on most tractors. As we discussed previously, any tractor that uses a common rail engine has an ECM which controls the function of the engine. Along with controlling the function of the engine, the ECM also controls the emissions systems. When the systems sense a plugged filter, a malfunctioning sensor or any other problem, they illuminate the check engine light or DPF light. If you ignore the lights, the engine will eventually derate. This means the ECM sensed an issue, it wasn’t addressed and it will try to protect the engine by not letting you use it. You might be able to idle and move around but you won’t be able to do any work. The ONLY way to fix a derate on a common rail engine is to have the manufacturer’s software to reset the system or further troubleshoot what’s causing the problem.

The nitty gritty on tractors in the 40hp class…

Kioti DK4510 uses the Daedong-Kioti 3F1863T-45 motor which uses an electronically controlled common rail fuel system, has a cooled EGR valve and both a DOC and DPF.

LS XR4510 uses the LS Mtron L3C19-T motor which uses an electronically controlled common rail fuel system, has a cooled EGR valve and both a DOC and DPF.

New Holland Boomer 45 is essentially the same tractor as the LS and uses the same motor and systems.

Kubota L4701 uses the Kubota V2403-CR-E4 motor which uses an electronically controlled common rail fuel system, has a non cooled EGR valve and both a DOC and DPF.

John Deere 5045E uses the PowerTech 3029H motor which uses an electronically controlled common rail fuel system with both a DOC and DPF but no EGR valve.

Mahindra 2645 uses a Mahindra motor which uses an electronically controlled common rail fuel system, has an EGR valve and only a DOC.

And finally, the TYM T474 uses the Kukje motor which has a mechanical fuel injection pump and only a DPF.

A note on Mahindra and their mCRD engines… Mahindra touts their tractors as regen free, and yes they are. However, with Mahindra you still get all the complexities of an electronically controlled common rail engine. It’s prone to sensor, harness and computer failure. While it doesn’t have to regen it still has a DOC which if you remember from earlier is like the catalytic converter on your car. It will get plugged up eventually and the only thing you can do is replace it. With emission rules tightening up every year, it's only a matter of time until Mahinda is also forced to use a DPF.

Let’s dive in to the Kukje and how it compares to the others. As we’ve said the Kukje motor uses a mechanical fuel injection system. From all the research I have done, it appears that the Kukje is the ONLY mechanical diesel engine in tractors of 40-59hp. This means that this tractor will start and run without any electronic controls, computers or sensors - just like your dad’s and grandfather’s did. The DPF system on the Kukje motors is supplemental the motor, it has its own computer and control system. SEPARATE FROM THE MOTOR. There is no diagnostic software for the Kukje motor, because it doesn’t need it. Now, when the DPF full light comes on, you will still need to perform a regen but everything about the process is infinitely simpler than the others.

Common rail engines have their place. They are quieter, more fuel efficient, and “smell” less. However, when it comes to a tractor simpler is better. That’s why the Kukje is the best of both worlds since it is a simple mechanical engine but also has a DPF which significantly reduces smoke and particulate emissions. In my opinion, DPF systems get a bad rap and most of the issues are from misinformation or improper operation. We have a very large shop and whenever you start up a 26hp tractor with no DPF the whole place fills up with smoke and smells like diesel very quickly. The engines with DPF systems DON’T! These systems aren’t only in place to protect the environment but also to protect users. While working a tractor you are breathing in the exhaust, wouldn’t you want to breath cleaner air? DPF’s make it possible.  

You might be asking “why haven’t I heard of Kukje?” Is it junk? ABSOLUTELY NOT. Kukje has been making diesel engines since 1968. For a while it made John Deere tractors under contract. For another while, it made Cummins A series engines under contract for Cummins. Yes, that one and only Cummins we all know and love, contracted Kukje to make the A series for them. I wish everyone could start and hear a Kukje motor side by side with any of the competition. Everything would instantly be clear.

https://youtu.be/pLgTFXknP3o