Advanced Production Surface Preparation Technology Development for Ultra-High Pressure Diesel Injection
In 2007, An Ultra High Injection Pressure (UHIP) fueling method has been demonstrated by Caterpillar Fuel Systems - Product Development, demonstrating ability to deliver U.S. Environment Protection Agency (EPA) Tier 4 Final diesel engine emission performance with greatly reduced emissions handling components on the engine, such as without NOx reduction after-treatment and with only a through-flow 50% effective diesel particulate trap (DPT). They have shown this capability using multiple multi-cylinder engine tests of an Ultra High Pressure Common Rail (UHPCR) fuel system with higher than traditional levels of CEGR and an advanced injector nozzle design. The system delivered better atomization of the fuel, for more complete burn, to greatly reduce diesel particulates, while CEGR or high efficiency NOx reduction after-treatment handles the NOx. With the reduced back pressure of a traditional DPT, and with the more complete fuel burn, the system reduced levels of fuel consumption by 2.4% for similar delivery of torque and horsepower over the best Tier 4 Interim levels of fuel consumption in the diesel power industry. The challenge is to manufacture the components in high-volume production that can withstand the required higher pressure injection. Production processes must be developed to increase the toughness of the injector steel to withstand the UHIP pulsations and generate near perfect form and finish in the sub-millimeter size geometries within the injector. This project resulted in two developments in 2011. The first development was a process and a machine specification by which a high target of compressive residual stress (CRS) can be consistently imparted to key surfaces of the fuel system to increase the toughness of the steel, and a demonstration of the feasibility of further refinement of the process for use in volume production. The second development was the demonstration of the feasibility of a process for imparting near perfect, durable geometry to these same feature surfaces to withstand the pulsating UHIP diesel injection without fatigue failure, through the expected life of the fuel system's components (10,000 hours for the pump and common rail, 5000 hours for the injector). The potential to Caterpillar of this fueling approach and the overall emissions reduction system is the cost savings of the fuel, the cost savings of not requiring a full emissions module and other emissions hardware, and the enabling of the use of biodiesel fuel due to the reduced dependency on after-treatment. A proprietary production CRS generating process was developed to treat the interior of the sac-type injector nozzle tip region (particularly for the sac region). Ninety-five tips passed ultra high pulsed pressure fatigue testing with no failures assignable to treated surfaces or materials. It was determined that the CRS impartation method does not weaken the tip internal seat area. Caterpillar Fuel Systems - Product Development accepts that the CRS method initial production technical readiness level has been established. A method to gage CRS levels in production was not yet accomplished, but it is believed that monitoring process parameters call be used to guarantee quality. A precision profiling process for injector seat and sac regions has been shown to be promising but not yet fully confirmed. It was demonstrated that this precision profiling process can achieve form and geometry to well under an aggressively small micron peak-to-valley and that there are no surface flaws that approach an even tighter micron peak-to-valley tolerance. It is planned to purchase machines to further develop and move the process towards production. The system is targeted towards the high-power diesel electric power generators and high-power diesel marine power generators, with displacement from 20 liters to 80 liters and with power from 800 brake horsepower (BHP) to 3200BHP (0.6 megawatts to 2.4 megawatts). However, with market adoption, this system has the potential to meet EPA exhaust standards for all diesel engines nine liters and up, or 300BHP to 3200BHP (0.2megawatts to 2.4megawatts). Expected energy savings from improved fuel economy alone in Caterpillar engines using this approach is above 250 trillion British Thermal Units per year (BTU/yr) by 2020. Further fuel savings will be realized due to the reduced weight of the reduced emissions hardware on Caterpillar engines and machines. Enabling the use of biodiesel and other renewable fuels will accelerate the utilization of such fuels, to reduce US dependence on foreign oil and to create above 50,000 new US jobs by 2020, pushing estimated use to two to three billion gallons by that time frame. Biodiesel has been shown to actually REDUCE CO2 in the air by United States Department of Energy (USDOE) Reports, so this thrust will make major impact toward US contribution to reduction of green house gas emissions world-wide.
- Research Organization:
- Caterpillar Inc., Mossville IL
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- DOE Contract Number:
- EE0003452
- OSTI ID:
- 1039208
- Report Number(s):
- DOE/DE-EE0003452; TRN: US201209%%515
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
09 BIOMASS FUELS
10 SYNTHETIC FUELS
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
33 ADVANCED PROPULSION SYSTEMS
36 MATERIALS SCIENCE
ATOMIZATION
DEFECTS
DIESEL ENGINES
EFFICIENCY
ELECTRIC POWER
ENGINES
FUEL CONSUMPTION
FUEL SYSTEMS
GEOMETRY
MONITORING
NOZZLES
PARTICULATES
PULSATIONS
SPECIFICATIONS
STEELS
TARGETS
TESTING
TORQUE
US EPA
Compressive Residual Stress
Precision profile
Process Development
Ultra high pulsed pressure fatigue testing
Computed Tomography X-ray measurement
Cooled Exhaust Gas Recirculation
Diesel Particulate Trap
Green House Gas Emissions
Biodiesel
Alternate Fuels
Ultra High Pressure Common Rail Fuel System
After-Treatment
Ultra High Injection Pressure
Diesel Injection
Fuel System
Injector
Injector Tip
Technical Readiness Level
Injector tip sac
Injector tip spray holes