Air Blower Reduces Gasoline Engine Emissions
S. Himmelstein | March 14, 2018Secondary air systems are used to reduce gasoline engine emissions by accelerating catalytic converter heat-up. Pierburg GmbH has now further developed the associated secondary air blower and provided it with a speed-controlled motor, enabling secondary air injection across a much wider engine map range. The arrangement provides for the precise air mass required for accelerating converter heat-up to be injected into the exhaust system.
Through the secondary air pump, the new air blower reduces electric power consumption and emissions, in 
Source: Pierburg GmbHaddition to accelerating catalytic converter heat-up, facilitating compliance with such standards as EU 6.2, RDE, SULEV 20 or Beijing 6. The blower, which can run uninterrupted, also permits controlled particle filter regeneration independent of ambient and driving conditions.
What are the operating principles of secondary air injection? It accelerates converter heat-up during cold starts or repeated starts as on hybrid cars or during start/stop cycles. The technique consists in creating an oxidizable gas mixture through combustion under air shortage conditions in the combustion chamber. With the injection of air directly into the exhaust system, this gas mixture undergoes an exothermal reaction. The unburned exhaust constituents are oxidized and the temperature at the converter entrance point rises significantly. The consequences -- accelerated converter heat-up, reduced carbon monoxide and hydrocarbon emissions during the heat-up phase.
Air blowers currently are designed to cover a specific range of air mass flow rates. When this is low at low engine load/speed, a secondary air pump designed for a high air mass flow can lead to excessively lean and cool exhaust gases, which undermines the exothermal reaction.
For a high air mass flow rate, the air flow generated by the secondary air pump can be too low to trigger an exothermal reaction. An unregulated secondary air pump restricts the functional range of secondary air injection to a limited engine map range.
The new secondary air pump comes with a brushless 12-V motor and all the relevant electronics.
It's speed is variable and it can operate continuously, allowing any number of start/stops. It accelerates converter heat-up at any given point of time within a wide range of engine operating parameters and directs the necessary air mass air flow with absolute precision. On-demand air injection cuts energy use and prevents excessive cooling.
The secondary air pump can be controlled by a LIN bus or PWM and, since the blower is smaller, less installation space is needed.
Gas turbine generators require the most reliable equipment for their air-cooling and ventilation needs. The fans used in these systems are mounted onto gas-turbine generator packages for use in power plants as well as on cruise ships, oil rig platforms, and mobile generators. These systems are loaded onto tractor-trailer rigs or barges and moved to a site to generate power for events like the Super Bowl and concerts. Manufacturers of these gas-turbine generators are realizing it pays to have the right fan for the job from the start and are turning to Buffalo Fan to provide these unique solutions.
In the past, the OEM purchased the necessary fan equipment then mounted it on its gas turbine generators. These generator sets were then shipped to job sites all over the world and installed in coastal areas, jungles, deserts and other extreme locations (even water-based applications like cruise ships and oil rig platforms). A key requirement for these applications is that the fans need to be exceptionally corrosion resistant to withstand these severe environmental factors.
Noise attenuation is a major issue for power generators, both to protect workers’ hearing and to keep operation at the quietest level for any surrounding residential or business communities.
Power generation is a complex process. The power generation fan / blower equipment should be tough enough to avoid operational failure and to minimize installation and repair work. The rugged, high performance fans Buffalo Fan provided to a state-of-the-art hybrid energy center, were ideal for the task. Aerovent was chosen for this project because of their reputation for building large custom fans for extreme industrial applications. The energy center’s primary requirement was that its chosen vendor be able to design and build a set of the most rugged, efficient roof ventilators within budget. Most roof ventilator fans last between 10 and 20 years when properly maintained. Because of the permits and cost involved in performing maintenance work on the roof of a power plant, they wanted their fans to have a longer life span (up to 40 years). This lifespan requirement meant that the fans had to be constructed using industrial grade materials and components.
Canada Blower propellers provide equal airflow in both directions. Other companies’ fans have a standard-exhaust one-direction propeller and are run backwards for the supply mode, producing about 40 percent of exhaust-mode airflow. ABuffalo Fan blowers produce 100 percent airflow in either direction. Aerovent also produced an integrated electrical control system guaranteed to work with its fans instead of the power plant having to acquire a separate system from another source. The system features an onboard starterdisconnect switch, which boosts the motor’s start and can be easily disconnected.
Fire safety is a challenge in any environment, and especially so in a power plant. In case of a fire, the first priority is to ensure the safety of employees. Another goal is to be able to salvage expensive equipment in the building. With ventilation fans, if the motor fails during a fire, it is more beneficial if the fan’s dampers automatically fail in the “open” position, and allow smoke to escape.
Canada Blower’s expertise in custom-building fans for complex applications, like this energy center, allowed them to design and construct a special fire damper for the fans. When the motorized damper is activated, a metal linkage arm attached to the damper blades moves to open or close the damper ventilating.com fanblower.com highpressureblower.n
Canada Blower custom made damper features a fusible linkage arm with a “soft metal” section in the link. When temperatures reach 212 degrees (as in the case of a fire), the soft metal plate fails, breaking the linkage, and a heavy counter weight swings the damper into the “open” position.