An engine is an extremely advanced product with several different systems that need to work together. The complex system integration should be controlled and optimized, not only based on fuel-efficiency and emission legislations but also driveability, reliability and uptime. This is the first part, of four, in our article series about engine technology and which different components that are needed to design an efficient engine that meets upcoming emission legislations.
New legislation drives the engine development forward
There are several reasons for the continuous development of new engine and exhaust aftertreatment concepts. New and modern technology, as well as increasing demands for maximised uptime, low fuel consumption and low cost of ownership, are just a few examples. However, one of the most common reasons for designing a new engine is to meet upcoming emission legislations. In January 2019, the new exhaust emission legislation for off-road engines will take effect on the European market. It is called Stage V and will further limit harmful substances in the exhaust gases. These substances include Nitrogen Oxides (NOx) and Particulate Matter (PM). Compared to Stage IV, which is the current legislation, Stage V will not only limit the overall mass of particulate matter in the exhaust gas but also the number of particles per unit of produced energy.
A balance of features to design a flexible and adaptable engine
Designing a new engine is a constant balancing of features. Fuel consumption vs NOx levels, low-speed response vs peak power and fuel consumption vs AdBlue consumption are a few of the engine’s features that must be weighed against each other. Even though an engine needs to meet current emission legislations, it must also be easy to install, have high uptime and require limited service and maintenance. In addition, an engine model might need to function in many different applications that work with different loads and speeds. To live up to all demands, the engine design needs to be flexible and adaptable.
A base engine and an aftertreatment system with a diesel particulate filter
There are countless ways to design an engine so it lives up to Stage V emission legislations. The key is to combine a base engine with an aftertreatment system and optimise them together in order to create a system that is as efficient as possible. The only way to live up Stage V emission legislations and reduce the number of particles per unit of produced energy is to add an aftertreatment system with a Diesel Particulate Filter (DPF) to the base engine. And, in order for the aftertreatment system and the DPF to function, it is crucial that the base engine is designed in a way that it produces the right amount of heat.
Generally, if you design an engine with an efficient combustion it will generate high combustion temperatures and that will, in turn, create nitrogen oxides (NOx). This means that the aftertreatment system needs to handle a large amount of NOx. However, the advantage of having an efficient combustion is that it leads to low fuel consumption. If you instead design an engine in the opposite way, using a colder combustion you might get slightly higher fuel consumption but the production of nitrogen oxides (NOx) decreases. However, in this case, more particles will be created instead.
Therefore, it is important to find a balance between the combustion temperature, the number of particles and the amount of NOx. For example, a high combustion temperature creates large amounts of NOx that put a high load on the Selective Catalytic Reduction (SCR), while a low combustion temperature creates a lot of particles putting pressure on the Diesel Particulate Filter (DPF).
Heat management system, common rail and turbo technology
To make sure the engine functions in an excellent way and still meets the Stage V emission legislations, it must contain a number of different systems that together create an efficient engine. The systems are:
- Exhaust Aftertreatment System (EATS). It is a system that needs to be connected to the base engine in order to decrease emissions. The main components in the aftertreatment system are the Selective Catalytic Reduction (SCR) that reduces the NOX and the Diesel Particulate Filter (DPF) that reduces the particles.
- Heat Management System, which is the system in the engine that controls the exhaust temperatures in order for the Exhaust Aftertreatment System (EATS) to function. The Heat Management System contains, for example, an air inlet throttle that helps to regulate the pressure in the engine.
- The fuel injection system that is a crucial part of an engine. Common rail is the latest fuel injection technology, featuring a high-pressure fuel rail feeding individual injectors. A benefit with the Common rail system is the high level of accuracy that is created with multiple injections.
- The right turbo technology, which is important when designing an engine adjusted for emission legislations. The choice is between two different systems, Fixed Geometry Turbo (FGT) or Variable Geometry Turbo (VGT).
Stage V engine with ease of installation, operation and maintenance
We, at Volvo Penta, are confident that we have designed a Stage V engine that focuses on high driveability and uptime, minimised fuel consumption and ease of installation, operation and maintenance.
Our Stage V engine is equipped with a fixed geometry turbo, which contributes to reduced complexity, improved fuel consumption and increased efficiency. A common-rail injection system reduces noise levels and delivers reduced fuel consumption. Volvo Penta has also chosen an uncooled exhaust gas recirculation (EGR), which delivers highly effective heat management for the engine. An electrical exhaust pressure governor (EPG) and inlet throttle enable the system to function without the need to inject fuel into the exhaust stream to raise the temperature. With this approach, the exhaust gas has an optimal temperature when it passes through the EATS. Low heat rejection from the complete system means that less cooling is required. Our Stage V engine also allows for an excellent regeneration strategy. This powerful combination leads to increased efficiency and uptime for the operator. In the end, that is our final goal – to help create an efficient and beneficial business for our customers while at the same time design our engines so they are as kind towards the environment as possible.
Our Stage V engine also allows for an excellent regeneration strategy. This powerful combination leads to increased efficiency and uptime for the operator. In the end, that is our final goal – to help create an efficient and beneficial business for our customers while at the same time design our engines so they are as kind towards the environment as possible.
I hope you enjoyed reading my introductory blog article about engine technology. If you have any questions or comments, please use the comment field below or contact me directly. You are also welcome to visit our website or social media channels where you can find out more about Volvo Penta, engine technology and Stage V emission legislations. And, most importantly, visit our Professional Power Blog to read more interesting articles.
In the upcoming parts of our article series, we will go more into detail on the different engine systems. Stay tuned for part two, which will describe the Exhaust Aftertreatment System (EATS).