Vintage Diesel Engine That Starts On Gas

International Harvester’s Gas Start Diesels

Making diesels user friendly was an uphill struggle in the late 1920s and early ‘30s. The advantages of the compression-ignition engine were generally known but the PITA involved in using one back then often outweighed those benefits. Part of the diesel reluctance was infrastructure related, such supply issues at the user level. Support for diesel powered equipment was few and far between in those days. Day-to-day, especially for hand-started engines, cold weather operation remained a big stumbling block.

The International Harvester Answer

International Harvester (IH) started experimenting with diesels in 1916 with a single cylinder prechamber design concocted in their own shop. Not much came of it but in 1927 the Gas Power Engineering Department bought a 4-cylinder German Dorner diesel to evaluate. The Dorner was impressive enough that in1928, IH engineers made three other experimental test engines and eventually came up with their own design. In 1930, they bought and tested other makes of German-made diesels against their design and found it worthy of production. part of that process was also to design and later build their own fuel injection systems.

Part of the base problem was to solve the starting issue. In large stationary applications, air start was the option. As engines got smaller, some of the smallest (mainly single cylinders) could be hand started but battery technology had not progressed far enough in the ‘30s to make electric start viable in most cases. Caterpillar, and others, used pony engines, a separate gasoline engine that ran long enough to heat the diesel a little and then spin it over. That worked very well but added a lot of bulk, expense and extra steps.

IH developed a system that combined a gas engine with a diesel. We’ll tell you exactly how in a sec, but the engine started on gasoline and then switched over to diesel after it was warmed up. In the long run, the gas start system was probably more user friendly, especially for equipment that had a lot of stop/start cycles, and it made the overall engine package more compact, and IH had the long term goal of adding diesel power to their smaller tractors. The pony-started engines were probably better diesels because they didn’t have to make any tradeoffs on the diesel part of the design. That worked for Cat because the majority of their equipment was bigger. It’s not so much a “which is better” question but more two roads to the same place, each route chosen to better serve the needs of each company.

The Production Engines: PD-40 
and PD-80

The early IH diesels were initially based on IH heavy-duty gas engine architecture. This aided both the development and especially the manufacturing, where at least some of the gas and diesel components could be manufactured on the same tooling. The first production IH diesel was dubbed the PD-40 and debuted in April of 1933. If it was in a crawler, it would be called a TD-40. In a wheeled tractor, the WD-40. A power unit would be a UD-40. If in an Industrial tractor, it was the ID-40. The engine designation was also the tractor designation in this era.

The big innovation was the gas start feature. Look at the nearby illustrations for more detail, but the essential feature of a gas start diesel was an auxiliary combustion chamber connected to the main diesel chamber by what was called a starting valve. When that was opened, the added volume of the auxiliary chamber dropped the compression ratio from 15:1 to about 5:1 and it contained a spark plug fired by a magneto. The gasoline intake tract was connected to the diesel system via an air valve. A small 3/4-inch bore carburetor supplied enough air and fuel to run the engine at about 400 rpm. A lever connected to various linkages opened or closes valves to the various chambers and disabled either the magneto or the injection pump. It worked better than you might think, especially when viewed in the context of the era when “diesel” and “cold starting” were exclusive terms.

The first generation IH diesels would be manually switched over to gas engine for starting and hand cranked. No, these first engines did not have electric start. The injection pump had a timer that counted the number of engine revolutions (about 700) and it could be used optionally to automatically trigger the system to switch back to diesel operation after approximately two minutes running on gasoline. In most cases, two minutes of running was enough to warm the engine enough to run on diesel but the operator could run the engine on gas as long as needed.

A six-cylinder diesel began development in 1933 and was released for production as the PD-80 in February of 1936, debuting in July. It was essentially the PD-40 with two cylinders added. It was a stout seven main engine with wet sleeves. It did have some design evolution over the PD-40, notably an improved combustion chamber. Making 691 cubic inches from the 4.75 x 6.50 bore and stroke, the engine cranked out a maximum of 100 horsepower and 80 continuous horsepower at 1400 rpm. It didn’t find a home in tractors but was offered in a power unit starting in 1937.

The PD-35 engine was a short-lived variant of the PD-40 that only appeared in the ‘37-39 TD-35 crawler. With a bore 1/4-inch smaller than the PD-40, it made four horsepower less, as measured in Nebraska tractor tests. As far as we can see, the PD-35 engine was not offered in anything but the TD-35 crawler, which was marketed as a “budget” TD-40.

TD-14/TD-18

The TD-40 and TD-80 evolved in 1939 with a large number of improvements. The evolution had begun with the 1936 updates mentioned. The original engines were basically sound and reliable, so the main thrust was improving combustion efficiency and increasing output. Major changes occurred to the cylinder head, combustion chambers, fuel injection and the way the gas start system operated. As such, the UD-40 engine became the UD-14 and the UD-80 became the UD-18. The UD-18 found a home in the TD-18 tractor at the end of 1938, making it IH’s most powerful crawler for a time. Initially, the maximum output of the four-cylinder engine increased to 81 horsepower maximum, 68.5 intermittent and 54 horsepower continuous. The six jumped to 119 max, 100 intermittent and 80 continuous. The power increases were not gigantic but efficiency and economy was much improved.

In 1946, another upgrade was released for production, the UD-14A and UD-18A, incorporating more improvements in breathing and combustion chamber design. The result was a maximum of 90.5 horses for the UD-14A and 150 horses for the UD-18A. This series of engines would remain in production into the early ‘60s. The UD-14A is still seen in the 1960 engine catalog but not the UD-18A, which ended in 1958, replaced by more modern six-cylinder designs.

New Kids: UD-6, UD-9 and UD-16

In 1939, two smaller gas-start, four-cylinder diesel engines were released for production, the 248 cubic inch UD-6 (3.88 x 5.25-inch bore and stroke) and the 334 cubic inch UD-9 (4.40 x 5.50-inch bore and stroke). The UD-16 was a six-cylinder variant of the UD-9. Both the fours were available in tractors or as power units. Following previous convention, the UD-6 appeared in the 1940 TD-6 crawler and the  WD-6 wheeled standard tractor and in the 1941 Farmall MD, International’s first rowcrop diesel.

The UD-6 shared a lot of features with the gas and distillate engines that had debuted with the new model M wheeled tractors and the W6 that had debuted for 1939. These new fours were dry sleeved with three main bearings. The new UD-6 delivered a maximum of 45 horsepower at 1500 rpm, though the continuous rating was only 39 horsepower. This series engine used a new IH injection pump that debuted at the same time.

The UD-6, UD-9 and UD-16engines were updated in 1953 with bore increases, the UD-6 to 4 inches and the UD-9/UD-16 to 4.5. This bumped the displacement to 264 and 350/525 cubic inches respectively. With some accompanying tuning and a 100 rpm bump in the redline, the UD-6 delivered a max of 54 horsepower and the UD-9 78.5. These engines saw use in the “Super” versions of the MD, WD-6 and WD-9, as well as with power units. They also appeared in the updated tractor lines like the 400 Farmall from 1954-56 and the W400 standard.

The final evolution of the UD-6 engine line came in 1956, with another bore increase to 4.125 inches. This bumped the displacement to 281 cubic inches. As far as we can determine the TD-9 engine continued on as it was until it was discontinued in 1958.

The Biggest Boy: UD-24

The biggest gas start IH diesel was the UD-24, used in a power unit and the TD-24 crawler starting in 1947. It was a beast, making 1,091 cubic inch from a 5.75 x 7.00 inch bore and stroke. In the big IH TD-24 crawler (built 1949-1959), it made 146 horsepower on the drawbar. Around 1955, IH adopted new terminology and renamed this engine the UD-1091 and it was offered as a stationary unit at least through 1960.

The Final Word

IH got a lot of mileage out of their gas start designs and even late in their 30 year run, when the diesel industry was finally getting a handle on cold starting issues, those so-called “all-weather diesels” still had a strong place in the market. Their design left a few horsepower on the table compared to what came later but even as improved IDI and DI engines came on the market, a lower-power diesel that starts on that cold and snowy day is better than a higher power one that doesn’t.

FREQUENTLY ASKED QUESTIONS

What is Reactivity Controlled Compression Ignition (RCCI) and how does it work?

Reactivity Controlled Compression Ignition (RCCI) represents a groundbreaking approach within internal combustion engine technology. It combines multiple fuel types to optimize efficiency while reducing emissions, thus addressing some of the critical contemporary challenges in engine design.

How RCCI Works:

1. Dual Fuel Injection System: At its core, RCCI utilizes two distinct fuel injectors for each engine cylinder. This design allows for the introduction of both a low-reactivity fuel, like gasoline, and a high-reactivity fuel, such as diesel. The selection of these fuels is key to the process.
2. Fuel Mixing: The process begins with the introduction of a mixture of gasoline and air into the combustion chamber. This mixture forms the base upon which additional processes act.
3. Diesel Injection and Mixing: As the piston ascends toward the top of its stroke (known as top dead center), diesel fuel is injected. The interaction between the initial gasoline-air mix and the newly introduced diesel is crucial. This phase promotes thorough mixing of the fuels.
4. Controlled Ignition: Just before the piston reaches its highest point, a final injection of diesel occurs. This precise timing initiates combustion, igniting the mixture in a controlled manner that aims for complete and efficient fuel burning.

The combination of these steps results in heightened efficiency, potentially surpassing traditional engines. By leveraging both gasoline and diesel fuels, RCCI seeks to maximize the strengths of each, thereby optimizing overall engine performance and minimizing emissions.

Why is the RCCI engine more fuel-efficient and cleaner than conventional diesel engines?

Why the RCCI Engine Outperforms Conventional Diesel Engines in Efficiency and Cleanliness

When it comes to optimizing fuel efficiency and minimizing emissions, the Reactivity Controlled Compression Ignition (RCCI) engine stands out as a superior alternative to traditional diesel engines. Here’s why:

Superior Fuel Efficiency

1. Dual-Fuel Capability: The RCCI engine utilizes both gasoline and diesel fuels, allowing for a more flexible and efficient combustion process. This dual-fuel approach significantly reduces fuel consumption by optimizing the burning of fuel mixtures.
2. Optimized Combustion: By meticulously controlling the combustion process, RCCI engines achieve a more complete and efficient burn. This leads to improved energy conversion from fuel to power, ultimately using less fuel to produce the same amount of energy.

Enhanced Cleanliness

1. Lower Emissions: The controlled ignition in RCCI engines minimizes the production of nitrogen oxides (NOx) and particulate matter, common pollutants in diesel engines. This cleaner burning process results in substantially reduced exhaust emissions.
2. Reduced Carbon Footprint: With better fuel efficiency and lower emissions, RCCI engines contribute to a reduced carbon footprint. This makes them a greener option compared to their conventional diesel counterparts.

Innovative Design and Technology

• Advanced Control Systems: RCCI engines are equipped with sophisticated electronic controls that precisely manage fuel injection and combustion timing. This precision enhances their overall efficiency and cleanliness.
• Thermal Efficiency Improvements: The unique design decreases heat loss during combustion, which further elevates thermal efficiency and reduces fuel consumption.

In conclusion, RCCI engines provide a compelling combination of efficiency and environmental friendliness, leveraging advanced technology and dual-fuel capabilities to outperform traditional diesel engines.

What potential does RCCI have for the future of internal combustion engines?

Unlocking the Future of Internal Combustion: The Promise of RCCI

Reactivity Controlled Compression Ignition (RCCI) is proving to be an exciting frontier for internal combustion engine technologies. With the potential to revolutionize efficiency standards, RCCI offers a blend of innovation that could change how we perceive combustion engines.

Unprecedented Efficiency

The key advantage of RCCI is its ability to use both gasoline and diesel to achieve unprecedented thermal efficiency. In controlled tests, this engine has delivered a staggering 60% thermal efficiency. To put this into perspective, conventional advanced engines today typically hover between 40% to 50% efficiency. This means that RCCI can convert more of its fuel into usable power, minimizing waste and setting a new benchmark for engine performance.

Cleaner and Greener

But RCCI isn’t just about efficiency. This innovative engine design is also more environmentally friendly than traditional diesel engines. Its dual-fuel approach inherently reduces emissions, offering a promising pathway to achieving stricter environmental standards without sacrificing power or performance.

Why Isn’t RCCI in Your Car Yet?

Despite its potential, RCCI is still in the experimental phase and currently limited to test bench trials. Significant research and development are necessary before it becomes a viable option for mass production. This process includes overcoming technical challenges and ensuring that it meets commercial viability and regulatory standards.

The Path Forward

While it may take time before RCCI engines hit the roads, the prospects are thrilling. This technology could redefine the internal combustion engine’s role in a world increasingly leaning towards sustainability. With continued innovation, RCCI might just be the key to bridging the gap between current combustion engines and a more sustainable automotive future.

What are the challenges preventing RCCI from being used in mass-produced vehicles?

Challenges Preventing RCCI from Mass Production

Reactivity Controlled Compression Ignition (RCCI) technology holds promise for the automotive industry, yet several hurdles must be overcome before it can be utilized in mass-produced vehicles.

1. Development Stage: The technology is still under development, requiring significant advancements before it reaches the mass production stage. This progress could take a considerable amount of time.
2. Dual Fueling Systems: One of the main technical challenges lies in the necessity for vehicles to be equipped with two separate fueling systems. This complexity increases both the cost and the engineering requirements for manufacturers.
3. Infrastructure Limitations: The current fueling infrastructure is not set up to support dual-fuel systems on a large scale. Significant investments in fueling stations and support networks are needed.
4. Cost Implications: Implementing RCCI technology could initially be expensive, both in terms of manufacturing and at the consumer level. This might deter manufacturers from investing heavily without a clear demand from the market.
5. Regulatory Approval: Before being integrated into vehicles, RCCI systems must pass rigorous testing and receive regulatory approval, which can be a lengthy and uncertain process.

Overcoming these challenges requires coordinated efforts across research, industry investment, and support from policymakers to pave the way for RCCI’s future on the roads.

How does the combustion process in RCCI differ from conventional engines?

In traditional engines, the combustion process typically begins with a spark igniting a pre-mixed combination of fuel and air. However, Reactivity Controlled Compression Ignition (RCCI) takes a different approach.

How does RCCI differ?

1. Fuel Mixing: Instead of relying solely on one type of fuel, RCCI uses a blend of fuels with varying reactivity levels. A low-reactivity fuel like gasoline is pre-mixed with air and introduced into the combustion chamber. Meanwhile, a high-reactivity fuel such as diesel is injected directly.
2. Fuel Injection Timing: In RCCI, the injection timing is crucial. As the piston ascends towards the top of its stroke, small amounts of diesel are injected at precise moments. This timing ensures optimal mixing and controls the ignition process.
3. Controlled Combustion: RCCI allows for more precise control over the combustion process. By manipulating the fuel mix and injection timing, combustion can be managed to reduce emissions and improve efficiency.

Ultimately, the RCCI process enhances engine performance by offering greater control over combustion, unlike conventional methods that rely heavily on spark initiation. This results in a cleaner and more efficient engine operation.

How does RCCI achieve high thermal efficiency compared to other engines?

How RCCI Achieves High Thermal Efficiency

Reactivity Controlled Compression Ignition (RCCI) technology stands out for its ability to boost thermal efficiency in engines. But what makes RCCI so much more efficient than traditional engines? Let’s break it down.

Dual-Fuel Magic

RCCI employs two types of fuel to achieve superior combustion efficiency. It combines a low-reactivity fuel, such as gasoline, with a high-reactivity fuel, like diesel. This unique mix is not just a matter of preference; it’s a strategic choice that maximizes energy output.

Optimized Combustion Process

1. Initial Mixing: The process begins with a mixture of air and gasoline entering the combustion chamber.
2. Diesel Injection: As the piston ascends, a specific amount of diesel is injected. This precise timing encourages a more thorough mixing of fuels.
3. Controlled Ignition: The final diesel injection, when the piston reaches top dead center, ignites the mixture. This controlled ignition results in a more complete and efficient burn.

Benefits Over Conventional Engines

• Fuel Efficiency: RCCI engines extract more energy from the fuel due to the high degree of mixing. This efficiency translates into better mileage and reduced fuel consumption.
• Lower Emissions: Beyond efficiency, RCCI also burns cleaner than the traditional diesel engine, cutting down on harmful emissions.

Conclusion

By optimizing the combustion process through precise fuel mixing and injection strategies, RCCI engines not only achieve high thermal efficiency but also offer environmental benefits. This combination of factors makes RCCI a promising technology for the future of efficient and sustainable engine design.