Cummins has unveiled its technology path to move its renowned ISB 4 and 6 cylinder products to Euro VI emissions regulations in 2013. The engines will use a combination of cooled exhaust gas re-circulation (EGR) and variable geometry turbocharging (VGT) on the engine allied to a new aftertreatment system incorporating particulate filtration (DPF) with selective catalytic reduction (SCR).
Neil Pattison, Director – Automotive Engine Business for Europe, Middle East and Africa, said: “For medium duty truck and bus use, the near-zero levels of emissions legislated at Euro VI mean that the majority of manufacturers will no longer have a choice of which technology to adopt. They will need to use all of them. However, the way in which OEMs balance these technologies in their emissions ‘recipe’ will have a major impact on the end product.”
Cummins technology choice is the result of one of the most comprehensive development projects undertaken at its European technical centre. By the time Euro VI is implemented, in excess of 80,000 hours of engine testing will be completed in the state-of-the-art facility and more than 2 million road miles will be driven to refine and validate the technology..
The Euro VI project is just one in a line of successful emissions launches from Cummins. The engineers have a record of delivering products on time to meet the regulations whilst also provide added value to customers. So why is Euro VI different from the previous steps? Effectively it is built on the development work and experience from Euro IV, Euro V, EPA 2010, as well as off-road EU Stage 3B and 4. It is also likely to be the final step in NOx and PM emissions reductions, given the 99% reduction to date since Euro I began in the 1990’s.
The regulators in the EU have also taken some learning from the previous steps and have included additional features into Euro VI which are placing more challenges on engine and vehicle manufacturers.
The move to the World Harmonised transient and steady state test cycles means that the engine testing is much closer to real world vehicle operation than the previous more theoretical cycles. Maintaining aftertreatment operational efficiency is more difficult under this new testing regime, with efficiency being closely linked with the heat management of the system.
The addition of particulate count measurement has driven all manufacturers to use particulate filtration in their exhaust systems. Particulate mass is poorly correlated with particulate number count and the previous measurement process is no longer capable of accurately measuring the extremely low particulate levels required by Euro VI, so this has also led to a new development focus. New measuring equipment has been specified for test cells to get to the required ultra low levels and complete the engine certification.
“Although we can use the substantial EPA 2010 experience gained to date, Euro VI products need to be fully developed for European specific test cycles, vehicles and duty cycles,” added Pattison.
The EU is introducing portable emissions measurement systems for in-service vehicle testing. This is to ensure that they remain compliant under normal operating conditions during the useful life of the vehicle. Engines must not exceed 1.5 times the laboratory emissions levels for 7 years or 700,000 km.
The in-service testing will be backed up by more stringent on board diagnostic (OBD) regulations, measuring exhaust emissions during vehicle operation. A threshold on particulate emissions will be included for the first time. Tougher NOx and anti-tampering limits will be introduced including an Adblue quality sensor. The tuning of the engine and aftertreatment to meet OBD requirements is vastly more complex than Euro V. There is also a phasing in period of OBD limits from 2013 to 2015 which needs to be managedbeyond the initial legislated date.
Manufacturers are required to issue repair and maintenance information to ensure emissions and OBD compliance is sustained throughout the vehicle life. Detailed product and service information needs to be published to enable the effective repair of the engine and aftertreatment system.
The enforcement of OBD failures is dependent on individual EU member states and how they implement it into law. This could involve roadside checks or be part of periodic inspections such as the MOT in the UK. An active malfunction indicator lamp (MIL) or long term fault could result in failure of the periodic inspection or even fines for the operator.
“Never before has the installation of the engine and its related technologies had the potential to impact the vehicle and its operation as much as it has at Euro VI. Cummins air handling-to-exhaust capability, with all leading technologies in-house, means that we can deliver the optimum recipe in terms of emissions, performance and operating costs. For instance, balancing EGR and SCR to reduce NOx is important to gain the lowest levels of fuel consumption and Adblue usage, with Adblue consumption being directly proportional to grams of NOx removed,” concluded Pattison.