POWERTRAIN


form our business around these trends. Our gasoline direct injection team has introduced a novel 500 bar direct injection system, while our electrification business has been able to step straight into next-generation technologies such as 800 volt inverters that help solve the range and charging challenges of electric vehicles.


FROM DIESEL TO HIGH-PRESSURE GDI


In the heavy-duty long-haul truck sector, there is currently no realistic alternative to diesel. The weight and cost of batteries aren’t economical for an electric (or highly electrified) powertrain solution. In the high-load, steady-state conditions of long haul, diesel engines are very efficient, with excellent power density, low carbon dioxide emissions, and low pollutants with aftertreatment. So, for heavy-duty commercial vehicles, we are about to launch a new generation of ultra-high precision fuel injector that uses an innnovative 1mm valve to improve the injector’s opening/closing speed and thus its ability to deliver fuel flexibly and shape the combustion event. When combined with fuel delivery pressures up to 3,000 bar and up to nine injection events per cycle, this allows much cleaner combustion, which means lower engine-out emissions and excellent fuel economy. Faster control means peak temperatures, and hence NOx, can be reduced, multiple pilot injection events can be employed to enhance refinement by slowing the rate of pressure rise, while multiple post- injection events can be specified to reduce soot formation. The durability targets for medium and


heavy-duty trucks are exceptionally demanding, so manufacturing innovation is a key part of product development. We are working with sub-micron


Microvalve pilot production at Delphi Technologies’ factory in Gloucestershire


clearances, with tolerances at least as demanding as those found in the latest jet turbines. Grinding processes using cubic boron nitride (CBN) have been developed beyond anything that had previously been achieved, complemented by new surface finishing techniques to eliminate burrs at the sub- micron scale. For passenger vehicles, gasoline engines continue to take market share from diesels. Traditional gasoline port fuel injection systems have been replaced by Gasoline Direct Injection (GDi), allowing more efficient combustion while mating well with turbochargers to enable the additional efficiency gains of engine downsizing. As with diesel injection, the key is


very fast, high-precision control of fuel injection events at high pressures. We were first to market with a GDi system operating at 350 bar fuel pressure, and at the 2019 Vienna Motor Symposium, we revealed a new 500+ bar GDi system that can reduce particulate emissions (both mass and number) by up to 50% compared with today’s state-of-the-art 350 bar system. Reducing engine-out emissions cuts tailpipe emissions in the crucial period before catalyst light-off and allows post Euro 6d and China 6 emissions standards to be


achieved with simpler after-treatment. Higher fuel pressure can also make the combustion process more efficient, which may offer an improvement in fuel economy of up to 1%. As with the new system for medium- and heavy-duty diesel engines, manufacturing innovation has been an important part of the development process for GDi. Switching to a forged high-pressure fuel rail, for example, has allowed a 25% component weight saving. More advanced materials have allowed simplified fabrication with reduced welds and fittings while also enhancing durability. Materials innovation has also been


central to our ability to solve one of the biggest challenges with higher pressure GDi. The industry has struggled to figure out a way to provide higher fuel pressures without putting additional stress on other engine components that would then require costly re-engineering and upgrading. Our solution is an innovation to the GDi pump plunger sealing that allows it to come up to pressure very quickly (around 23% faster than today’s typical GDi systems) and to maintain pressure at low RPM – both critical for fuel economy and emissions – while actually reducing stress on the camshaft drive surfaces by up to 30%.


THE FUTURE OF ENGINES


The Viper 4 inverter swirch


We believe that the internal combustion engine will be around for many years to come. I have already mentioned its


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