MAN Engines
Naturally aspirated and turbo engines from MAN Engines
In focus:

Naturally aspirated and turbo engines from MAN Engines

Focus on electricity or heat production: Best possible efficiency through application-optimised gas engines

In its gas engine portfolio, MAN Engines offers a wide selection of turbocharged lean-burn and naturally aspirated engines with stoichiometric combustion. Depending on the application, each engine technology has its advantages. Whether the focus is on electricity production or the primary use of heat, MAN Engines has the appropriate solution for higher efficiency.

Naturally aspirated engines from MAN Engines

Advantages of MAN naturally aspirated engines

MAN naturally aspirated engines are the perfect choice when the primary aim is to generate heat. Due to a combustion air ratio of λ=1, naturally aspirated engines generate about three to six percent more thermal energy output than turbocharged engines. Since naturally aspirated engines do without cost-intensive components such as turbochargers and mixture coolers, their purchase price is significantly lower than that of turbocharged engines. The reduction of maintenance-intensive assemblies and lower mechanical and thermal stress also increase maintenance intervals and reduce costs. A particular advantage of MAN naturally aspirated engines is their use with a cost-effective three-way catalytic converter. This allows nitrogen oxides (NOx) and carbon monoxide (CO) to be reduced to values as low as < 100 mg/Nm3.

Naturally aspirated engines from MAN Engines are always the best choice when there is primarily a high demand for heat or when emissions are to be reduced to a low level cheaply and reliably.

MAN Engines offers naturally aspirated engines in the power range from 34 kW to 300 kW for markets with mains frequencies in 50 Hz and 60 Hz for operation with natural gas. In the 300 kW range, MAN Engines is making a clear statement through its sole position in the market!

Naturally aspirated engines from MAN Engines

Advantages of MAN turbo engines

MAN turbo engines are supercharged gas engines with lean combustion. These turbocharged lean-burn engines deliver more electrical power through turbocharging, which also enables higher mechanical efficiencies. But even under adverse conditions and at high altitudes, combined heat and power units (CHPs) and gensets with turbo engines from MAN Engines have proven their performance and reliability many times. If solutions for exhaust gas aftertreatment are necessary, MAN relies on its tried and tested SCR system for turbo engines, which has also proven itself many times in numerous mobile applications.

MAN Engines turbocharged engines focus on the production of electricity and the additional generation of heat. Furthermore, they are used in applications with higher power requirements than naturally aspirated engines.

MAN Engines turbocharged engines are available in the power range 68 kW to 580 kW with 1,500 rpm and 1,800 rpm. These are operated with natural gas or with CO2 neutral special gases, e.g. biogas from agricultural biogas plants or sewage gas from municipal sewage treatment plants.

Combustion air ratio (lambda):

  • Stoichiometric combustion air ratio: The fuel-air mixture in the gas engine combustion chamber is considered stoichiometric if all fuel molecules could react completely with the atmospheric oxygen, thus no oxygen is missing and no unburnt fuel remains. This complete combustion has a combustion ratio of λ (lambda) = 1.
  • Rich combustion air ratio: The air ratio is λ < 1 (e.g. 0.9), i.e. there is more fuel in the engine combustion chamber than air required for combustion (rich gas mixture).
  • Lean combustion air ratio: So-called lean-burn engines operate with a combustion air ratio/lambda > 1. For example, with λ > 1.5, 50 % more air molecules can be fed into the combustion process than would be necessary for the stoichiometric reaction (lean gas mixture).

Comparison of MAN naturally aspirated engine with MAN turbocharged engine

  Lambda 1 naturally aspirated engines Turbocharged lean-burn engines
Purchase price per kW installed capacity +++ +++
Service interval +++ ++
Maintenance costs +++ +
Efficiency, thermal +++ ++
Efficiency, electrical/mechanical + +++
Output, electrical/mechanical + +++
Lowest NOx emissions can be achieved cost-effectively +++ +
Load imposition characteristics +++ ++
Exhaust gas aftertreatment options 3-way catalytic converter SCR system + Oxi cat
Operating media Natural gas Natural gas
Special gases (e.g. biogas, sewage gas)