Combustion Pressure Sensor

Combustion pressure sensors that take the combustion efficiency of internal combustion engines into a new generation

The current internal combustion engines used in automobiles have a combustion efficiency of only around 30% at best, and they cannot convert all of the energy from the fuel into power.
Amid calls for energy savings, all of the automobile manufacturers are engaged in continuous research to increase combustion efficiency, but the fuel economy performance required of engines for automobiles is high, and it is not easy to satisfy this requirement.
As one means of responding to market demand, it is becoming increasingly important to ascertain what is actually happening inside the cylinders and to implement control in accordance with that status. What makes this possible is combustion pressure sensors.
To measure directly the combustion pressure inside the cylinders, which had been difficult to measure up until now, and make a major contribution to the realization of optimum combustion state.

Combustion Pressure Sensor


Our combustion pressure sensors have resistance to high temperatures allowing them to directly measure the pressure inside cylinders, and cost competitiveness to allow them to be incorporated in mass-production vehicles.

Combustion pressure sensors can be mounted in each of the cylinders of mass-production vehicles to support the realization of control matched to engine conditions as they change from moment to moment.

  • High-accuracy pressure detection by piezoelectric method

    ・Crystals with no Curie point: Proprietary langasite-type crystals we developed.

  • Compact design giving great versatility in installation

    ・Adoption of langasite-type crystals with high temperature resistance means that no cooling device is necessary.

    ・Even greater compactness is achieved with our original construction.

  • Low costs achieved through mass production

    ・Low costs are achieved by applying the production technology of the existing product range.

Citizen Finedevice will put the synergistic effects of the “Metal part machining technology”, “Hard / brittle material processing technology”, “Assembly technology” and “Automation technology” that the former Citizen Finetech Miyota Co., Ltd. and former Citizen Seimitsu Co., Ltd. built up while engaged in the manufacture of watch parts since the foundation of the two companies to good use supplying products to the automotive market.

The achievements start with combustion pressure sensors.

The mass production of these sensors requires the four technologies to be combined in a well-balanced way, embodying the “synergy” generated by the merger of the two companies.

In this way, apart from “synergy” that leads to further development of existing business, we are working to develop new products by combining the four technologies, and to hone these technologies further.


Cylinder pressure measurement and control in the engines of automobiles, motorcycles, ships and generators

Technical information

Particulars / Specifications

Pressure detection range : 0 to 25 MPa

Linearity : Within 0.5%

Response speed : Within 1 μsec