The History of Caterpillar Engines The start of Caterpillar engines actually begins before Caterpillar was even a company. The history began back in the late1800’s when Daniel Best and Benjamin Holt were experimenting with various forms of steam tractors used for farming. The two competed with each other to gain the lead in the farm equipment industry. Throughout the late 1800’s and early 1900’s Holt and Best continued to build both steam and gas tractors. In 1908 Best sold his company to Holt. In 1925 Holt Manufacturing and C. L. Best Gas Tractor, a company owned by Best’s son C. L. Best, merged to form Caterpillar Tractor Company.
Three years later C. L. Best met with Carl George Arthur Rosen to discuss putting diesel engines in the Caterpillar 60 Tractor. Rosen looked over other diesel engine designs for about a year. The real engineering didn’t start until 1929 and went through 1930. The company’s first diesel was on its way. In October of 1931, Caterpillar introduced the D9900. It produced about 89 hp at 700 rpm and weighed in at 5,175 lbs. The engine was first designed with a precombustion chamber due to the various types of fuels used in testing. Also, the fuel system was designed to be non-adjustable so no one could try to “improve” it themselves.
The D9900 was also the first diesel engine with an air filter. This engine would revolutionize the industry. After quite a few years the need for advancements became very apparent. One of the advances taken by Caterpillar was turbocharging. Turbocharging allowed more air to be put into the engine. With more air, you got more horsepower. It was an amazing advancement. A turbocharger is designed to use the engine’s wasted energy to create more power. As exhaust gases come out of the exhaust manifold, they pass through the turbine housing side of the turbo. As the extremely hot gas pass by the heat causes the turbine wheel to spin.
This wheel is connected to a shaft which is connected to a compressor wheel. So as the turbine wheel spins, it causes the compressor wheel to spin. The compressor wheel then draws in outside air and compresses it into the compressor housing. This housing then directs the compressed air into the engine. After the use of the turbocharger they discovered a new problem. The compressed air was much hotter than normal air going into the engine. The reason was that when the air is compressed it puts pressure on all the atoms. This causes the atoms to hit each other, causing friction, and move even faster.
These rapid movements cause a massive amount of heat. This excess heat caused less oxygen to get to the cylinders which means a loss of potential power. Our answer to this dilemma was the aftercooler. Aftercoolers are used to lower the temperature of the air after it comes out of the turbo but before it enters the engine. By lowering the temperature the air becomes denser and holds more oxygen. This increase in oxygen provides an increase in power. There are three types of aftercoolers. The first is an Air-to Air Aftercooler (ATAAC). With the air-to-air system, a separate cooler core is placed in front of the engine.
The engine fan then passed outside air across the cooler. The outside air is much colder than the compressed air in the cooler. This difference causes the compressed air to drop in temperature by losing its heat to the outside air. This method is very common on most on-highway trucks since they have access to a large volume of fresh cool air. The second type of aftercooler is the Jacket Water Aftercooler (JWAC). The jacket water system uses the engine coolant to cool the compressed air entering the cylinders. Coolant from the water pump flows through the aftercooler core. The compressed air is then passed along the outside of the core.
The coolant takes the heat away from the air which lowers the air temperature causing it to become denser. The third and final type of aftercooler is the Separate Circuit Aftercooler (SCAC). A separate cooling circuit used to cool the compressed air. The circuit has its own water pump, lines, and heat exchanger for the aftercooler. This system is very similar to the jacket water system. After the increase in air volume engineers had to develope a more efficient fuel system to keep up. The old pump and nozzle groups, which had mechanical fuel injectors, used a small camshaft and individual plungers to supply fuel.
This system was OK but couldn’t supply enough fuel for the amount of air going into the engine. This need led to the creation of a couple different types of fuel systems. The first type of system was an electronically controlled unit injection system. This system used a solenoid on the injector to control the rate of injection. The solenoid is controlled by the Electronic Control Module (ECM). The actually injection timing is still controlled by a lobe on the camshaft. The second type of system is the Hydraulically Actuated Electronically Controlled Unit Injector (HEUI). The HEUI system controls injection pressure electronically.
The injector uses hydraulic energy from pressurized engine lube oil for injection. The pressure of the incoming oil controls the rate of injection, while the amount of fuel injected is determined by the ECM. This system eliminated the injector lobe on the camshaft. Caterpillar engines have given them one of the most well known names around the world. They are known for their reliability and durability. Caterpillar engines are looked at with respect and admiration. The Caterpillar Company has spent almost one hundred years molding their company to be the best of the best.
When all this power was created it also created a lot of heat. Caterpillar decided to design a new engine oil to help cool and collect deposits from the engine. Their new oil had a high quality base stock balanced with additives like ash dispersants, metallic detergents, deoxidizers, and multi-purpose inhibiters. These additives allow for improved soot dispersancy to maintain oil viscosity, and increased oxidation stability to reduce oil sludge. The new oil also reduces valve train and collects metallic deposits. Caterpillar named their new oil Cat DEO. After a while the EPA butted in and put restrictions on emissions.
Caterpillar answered with the development of Acert technology. This system uses the fuel and intake advancements to allow for better total burn of the fuel. This produces lower nitrogen oxide emissions. The system also uses a diesel oxidation catalyst to reduce emissions even more. Acert would not only meet today’s needs, but future needs as well. Caterpillar engines have come a long way since it started. They work hard on everything they design and make sure it is up to or surpasses given standards. That is why Caterpillar is one of the most well known companies in the world.
