Get the Full Picture with the Cat Gas Engine Rating Pro (GERP)


scenario. As Cat engines have improved so has GERP, keeping up to date on the latest in Cat power technology, including features like ambient-based ratings. In short, GERP has proven itself to be an invaluable tool for project engineers, providing the project-specific engine data and a library of reference literature to expedite any decision.

Every jobsite comes with its own challenges, but GERP takes out any guesswork that’s involved. Consider the wealth of features that GERP provides to project engineers:


  1. Performance predictions – GERP’s primary purpose is to predict engine performance for any jobsite, given a few parameters. Users punch in values for altitude, air temperature, aftercooler temperature, emission setting and site fuel composition, and GERP will output an exhaustive list of performance values. These include highest possible continuous power, air flow rates, fuel consumption rates and emission rates. Armed with this data, project engineers can quickly assess how a given engine will produce on site.

  2. Fuel analysis – Ideally, project managers can make extensive use of field gases to power their engines, but field gases are notorious for being unpredictable. Following field gas composition analysis, GERP users can model how a Cat engine will perform given a particular composition of field gas. With GERP’s fuel analysis, project managers don’t have to take chances with their iron. 

  3. Curves and graphs – GERP provides more than 20 graphs for every performance run, giving project engineers the insight they need to make informed decisions regarding component acquisition. Pump curves, for example, can help engineers select the most compact and efficient cooling system and appropriate piping diameters. 

  4. Reference drawings and materials – GERP maintains a complete library of drawings and published materials, like operating and maintenance manuals, to aid engineers in packaging their components. Drawings include reference to connection points for air, exhaust and fuel connections, making it easy for engineers to match components prior to acquisition. 

  5. Special rating requests – Occasionally, power systems have to be set up in adverse conditions. Extreme altitudes or temperatures can have a major impact on engine performance, and GERP can alert a user when certain engine and fuel parameters will not meet a project’s power needs. When this is the case, GERP provides access to Caterpillar factory performance engineers through Special Rating Requests (SRRs).  When possible, an SRR may provide additional information to help engineers decide on a course of action, such as modifying engine or fueling systems to get that extra bit of performance. 

  6. Emissions predicting – It’s not just about performance. Every state maintains its own environmental licensing board, with varying emissions standards. Because GERP can predict emissions rates to a precise degree, project managers can have high confidence that they will remain in line with state regulations. 

  7. Accelerated project completion timelines – GERP brings everything together into a single piece of software. With engine performance, emissions and site layout tools all available in one place, engineers can streamline their project management processes, and execute projects faster and with greater confidence.

If information is an asset, then GERP is the total package. For more than a decade, it has led the way in empowering engineers and project managers, giving them precise control over how they initiate and monitor their operations.

Gas Compression Engines

Gas Compression Engines

For gas lift, gas gathering, wellhead gas compression, pipeline compression, storage, gathering and reinjection, Cat engines are the prime choice for reliable gas compression.

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Gas Engine Rating Pro (GERP) is PC-based program designed to provide job-site ratings for Cat® natural gas engines within the gas compression industry.

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