Cylinder Deactivation and Variable Compression Ratio for Engines

Detailed overview of innovation with sample startups and prominent university research

What it is

  • Cylinder Deactivation: This technology selectively deactivates cylinders in an engine during low-load operating conditions, such as cruising at constant speeds. By effectively reducing the size of the engine when full power is not needed, cylinder deactivation minimizes fuel consumption.
  • Variable Compression Ratio (VCR): VCR technology allows an engine to adjust its compression ratio dynamically based on driving conditions. Higher compression ratios improve efficiency under high-load conditions, while lower compression ratios prevent knocking and improve performance at low loads.

Impact on climate action

Cylinder deactivation and variable compression ratio technology in low-carbon ICE vehicles significantly reduce emissions by optimizing engine performance. This innovation enhances fuel efficiency and lowers greenhouse gas emissions, contributing to mitigating climate change. It promotes a transition towards cleaner transportation, fostering greater sustainability in the automotive industry’s climate action efforts.


  • Thermodynamics: Cylinder deactivation and VCR technologies leverage thermodynamic principles to optimize engine efficiency. Reducing the number of active cylinders or adjusting the compression ratio allows the engine to operate closer to its ideal efficiency point across a wider range of operating conditions.
  • Mechanical Engineering: Both technologies involve intricate mechanical systems that can selectively deactivate cylinders or adjust the compression ratio. Precise control and actuation mechanisms are essential for seamless operation and integration with the engine management system.
  • Engine Control Systems: Sophisticated engine management systems use sensors to monitor engine load, speed, and other parameters to determine when to activate or deactivate cylinders or adjust the compression ratio.

TRL : 9

Prominent Innovation themes

  • Dynamic Skip Fire (DSF): This innovation, developed by Tula Technology, uses advanced algorithms and engine control systems to dynamically deactivate individual cylinders based on real-time driving conditions, offering greater flexibility and fuel-saving potential compared to traditional cylinder deactivation systems.
  • Electro-hydraulic VCR Systems: These systems use electro-hydraulic actuators to adjust the compression ratio more quickly and precisely, further optimizing engine efficiency across a wider range of driving scenarios.
  • Camless Engine Technology: This emerging technology eliminates the traditional camshaft, allowing for more flexible and precise control of valve timing and lift, potentially enabling a combination of cylinder deactivation, variable compression ratio, and other advanced engine control strategies.

Other Innovation Subthemes

  • Selective Cylinder Deactivation
  • Dynamic Cylinder Management
  • Precision Compression Ratio Control
  • Adaptive Engine Efficiency Systems
  • Thermodynamic Optimization Techniques
  • Mechanical Actuation Mechanisms
  • Advanced Engine Management Algorithms
  • Real-Time Driving Condition Sensing
  • Fuel-Efficient Cylinder Strategies
  • Dynamic Skip Firing Technology
  • Enhanced Cylinder Deactivation Algorithms
  • Electro-Hydraulic Compression Adjustment
  • Rapid Compression Ratio Adaptation
  • Smart Compression Ratio Adjustment

Sample Global Startups and Companies

  • General Motors (GM):
    • Technology Focus: GM is a leader in automotive engineering, and their implementation of Cylinder Deactivation and Variable Compression Ratio technology focuses on enhancing engine efficiency and fuel economy. Cylinder Deactivation enables the engine to seamlessly switch between running on all cylinders and running on fewer cylinders under light load conditions, reducing fuel consumption. Variable Compression Ratio technology allows for dynamically adjusting the compression ratio of the engine, optimizing performance and efficiency across different operating conditions.
    • Uniqueness: GM’s approach to these technologies often involves sophisticated engine management systems and advanced materials to ensure smooth operation and durability. Their continuous refinement of these technologies has led to improved fuel efficiency without compromising performance.
    • End-User Segments: GM’s vehicles equipped with Cylinder Deactivation and Variable Compression Ratio technology cater to a wide range of end-users, from compact cars to full-size trucks and SUVs. These technologies appeal to consumers looking for fuel-efficient vehicles without sacrificing power and performance.
  • Infiniti (Nissan):
    • Technology Focus: Infiniti, a luxury division of Nissan, incorporates Cylinder Deactivation and Variable Compression Ratio technology into their vehicles to deliver a balance of performance and efficiency. Similar to GM, Cylinder Deactivation optimizes fuel consumption by deactivating cylinders when full engine power is not required. Variable Compression Ratio technology further enhances efficiency by adjusting the compression ratio based on driving conditions.
    • Uniqueness: Infiniti’s implementation of these technologies often emphasizes refinement and luxury, with a focus on delivering a smooth and responsive driving experience. Their engineering efforts may also prioritize noise and vibration reduction to ensure a premium driving experience.
    • End-User Segments: Infiniti targets luxury vehicle buyers who seek both performance and fuel efficiency. Their vehicles equipped with Cylinder Deactivation and Variable Compression Ratio technology appeal to discerning customers looking for cutting-edge technology and advanced engineering in their automobiles.
  • Daimler (Mercedes-Benz):
    • Technology Focus: Daimler, the parent company of Mercedes-Benz, integrates Cylinder Deactivation and Variable Compression Ratio technology into their lineup of vehicles to optimize efficiency and reduce emissions. These technologies work in tandem to improve fuel economy without compromising performance, reflecting Mercedes-Benz’s commitment to innovation and sustainability.
    • Uniqueness: Daimler’s approach to these technologies often involves a blend of engineering excellence, luxury craftsmanship, and advanced driver assistance systems. Their implementation may include features like predictive analytics to anticipate driving conditions and optimize engine operation accordingly.
    • End-User Segments: Mercedes-Benz vehicles equipped with Cylinder Deactivation and Variable Compression Ratio technology cater to a diverse range of customers, from luxury sedan enthusiasts to SUV drivers seeking both performance and environmental responsibility. These technologies underscore Mercedes-Benz’s reputation for technological innovation and engineering excellence.

Sample Research At Top-Tier Universities

    1. Technical University of Munich (TUM):
      • Technology Enhancements: TUM researchers are delving into advanced control algorithms and sensing technologies to optimize cylinder deactivation and variable compression ratio systems in ICE vehicles. They aim to enhance the efficiency of these systems while maintaining engine performance and minimizing emissions.
      • Uniqueness of Research: TUM’s research stands out for its holistic approach, which combines expertise in mechanical engineering, control systems, and combustion science. They are exploring innovative methods to seamlessly transition between different operating modes, maximizing fuel economy and minimizing the environmental footprint of ICE vehicles.
      • End-use Applications: The research at TUM has direct implications for automotive manufacturers striving to meet stringent emissions regulations and improve fuel efficiency. By integrating cylinder deactivation and variable compression ratio technologies, vehicles can achieve significant reductions in carbon emissions without compromising driving dynamics or user experience.
    2. Aachen University:
      • Technology Enhancements: Aachen University’s research focuses on developing novel engine designs and combustion strategies to optimize the performance of cylinder deactivation and variable compression ratio systems. They are leveraging advanced simulation tools and experimental techniques to explore new configurations and operating conditions.
      • Uniqueness of Research: Aachen University’s approach emphasizes the integration of cylinder deactivation and variable compression ratio technologies with other engine subsystems, such as turbocharging and exhaust gas recirculation. They are investigating synergies between these technologies to maximize overall efficiency and minimize pollutant emissions.
      • End-use Applications: The research at Aachen University has implications for both light-duty and heavy-duty vehicle applications, including passenger cars, trucks, and buses. By adopting innovative engine designs and control strategies, manufacturers can develop low-carbon ICE vehicles that meet the performance and regulatory requirements of diverse markets.
    3. University of Michigan:
      • Technology Enhancements: University of Michigan researchers are exploring the use of advanced materials and manufacturing techniques to enhance the durability and reliability of cylinder deactivation and variable compression ratio systems in ICE vehicles. They are investigating the use of lightweight materials and innovative coatings to improve component longevity and reduce friction losses.
      • Uniqueness of Research: University of Michigan’s research distinguishes itself by its focus on real-world durability and reliability testing, complemented by predictive modeling and simulation studies. They are working closely with industry partners to validate their findings and accelerate the adoption of next-generation engine technologies.
      • End-use Applications: The research at University of Michigan has implications for automotive OEMs, suppliers, and aftermarket companies seeking to commercialize cylinder deactivation and variable compression ratio technologies. By addressing durability and reliability concerns, manufacturers can increase consumer confidence and drive widespread adoption of low-carbon ICE vehicles.

commercial_img Commercial Implementation

Cylinder deactivation and variable compression ratio technologies are already commercially available and have been implemented in various production vehicles by major automotive manufacturers. These technologies have demonstrated their effectiveness in reducing fuel consumption and emissions in real-world driving conditions.