Cylinder pressure sensors for use in large engines must meet special requirements. With the new pressure sensors (6636A2 and 7636A2), Kistler is raising the bar in this sector. Compared to their tried-and-tested predecessor models (6613CG2/7614CG2), these sensors have maintained a high degree of resistance to temperatures of 350°C while also dynamically expanding the overload range to 450 bar. This new generation of piezoelectric cylinder pressure sensors for slow-running large engines is therefore ideally prepared for new engine generations and the use of future fuels. The new sensors are also equipped with high-quality Kistler PiezoStar crystal technology, which is up to five times more sensitive than quartz. PiezoStar crystals offer excellent measurement stability at nearly any temperature. Continuous operation of the sensors for combustion monitoring in large engines requires an extremely robust design. Conventional plug connections for signal transmission have been replaced by welded connections, making the sensors far less sensitive to vibrations and guaranteeing significantly more stable transmission of measured values. Moreover, the unique anti-strain design of the new cylinder pressure sensors offers superior stress resistance.
New cylinder pressure sensors for monitoring and combustion optimization of large engines
Winterthur, May 2025 – Closed-loop combustion control (CLCC) guarantees optimal operation of large engines, in particular slow-running engines like those used in the shipping industry. Kistler is introducing a new generation of piezoelectric cylinder pressure sensors for continuous combustion control that feature an extremely robust design, a high degree of temperature stability and pressure resistance, and highly precise measurement results. The sensors have an extremely long service life and provide the electronic control system with the data base for continuous optimization of combustion processes. This, in turn, reduces fuel consumption and therefore the emission of harmful substances and particles. The new cylinder pressure sensors are designed for operation with both conventional fuels and future fuels such as hydrogen, ammonia and methanol.
Cylinder pressure sensors extend the service life of large engines
The use of cylinder pressure sensors can significantly extend the service life of slow-running large engines like the ones installed in container ships, thus playing a key role in sustainable operation. The cylinder pressure sensors monitor parameters such as cylinder pressure, time of combustion and knocking. The measurement results are fed into the closed-loop control circuit (CLCC) for combustion analysis. The electronic engine control intervenes in real time, adjusting the engine to balance the combustion processes in all cylinders. This decreases the mechanical strain on the engine, improves fuel efficiency and reduces emissions.
Combustion optimization in large marine engines to achieve (IMO) climate goals
In the medium term, large engines will have to continue to rely on combustion technology. At the moment, the majority of all large marine engines are still operated with heavy fuel oil; however, alternative fuels (future fuels) like LNG, ammonia and methanol are increasingly being used – either exclusively or in hybrid operation. Moreover, tests in which hydrogen is used to fuel slow-running large engines are currently underway. The 175 member states of the International Maritime Organization (IMO), a specialized agency of the United Nations, have made it their goal for international shipping to achieve net climate neutrality by around 2050. For that reason, it is essential to use advanced technology to reach both intermediate targets and the end goal. With the help of measurement technology – like cylinder pressure sensors from Kistler – the fuel consumption of marine engines can be reduced by around 1.8%. Carbon emissions are reduced proportionally. For example, a large marine engine would emit an average of 2,000 (metric) tonnes less CO2 in one year. Roughly 10,000 ships around the world are equipped with cylinder pressure sensors from Kistler, which help these ships to cut around 20 million tonnes of carbon emissions annually.
High-precision cylinder pressure monitoring for different engine types
The new generation of cylinder pressure sensors (6636A2 and 7636A2) for high-precision measurements on slow-running large engines are replacing the previous sensor generation (6613CG2 and 7614CG2). The sensors 6636A2 and 7636A2 are identical in terms of technical parameters; the only difference is the respective dimension of the sensor body and the installation thread. In addition to these sensor types, which are designed for installation in two-stroke large engines, Kistler also offers a sensor (6635A1) that is designed for use in four-stroke large engines.
