Weichai, Bosch Claim Efficiency Breakthrough

Brake thermal efficiency of 50.26% achieved for Weichai 13 L truck diesel

Chinese engine manufacturer Weichai Power and Bosch announced what the two companies called “a huge leap forward in engine technology.” The companies said they have successfully increased the brake thermal efficiency of Weichai diesel engine for heavy commercial vehicles to over 50%, setting a new global benchmark.

During a launch ceremony held in China, Germany’s TÜV SÜD and the China Automotive Technology and Research Center — the country’s national internal combustion engine testing organization — awarded Weichai certificates for brake thermal efficiency (BTE) of 50.26%. The engine was jointly unveiled by Ling Wen, vice governor of Shandong Province and academician of the Chinese Academy of Engineering; and Tan Xuguang, chairman of Shandong Heavy Industry Group and Weichai Group.

Currently, thermal efficiency for truck engines averages around 46%. Bosch supplies its modular common rail system for Weichai’s 13 L, six-cylinder diesel engine which is designed to meet the latest China 6 emissions standards. The engine is rated 560 hp (417 kW) at 1900 rpm.

“In increasing the efficiency by four percentage points, we have jointly reached a new milestone,” said Dr. Volkmar Denner, chairman of the board of management of Robert Bosch GmbH. “Even though the diesel engine is nearly 130 years old, its development continues.”

Over the last 10 years, Weichai said it has invested more than $%4 billion on diesel engine development. It credits the high brake thermal efficiency rate to five proprietary technologies.

– Weichai said its fields synergy combustion technology optimizes the design of the air passage, fuel injection, combustion chamber profile and other systems to make the relationship between the velocity field and concentration field in the combustion chamber more harmonious, increasing combustion speed by 30%.

– Weichai said its harmonious design technology enables the diesel engine block to withstand high peak firing pressure (PFP), which greatly limits combustion improvement, by about 60%. The technology also strengthens the engine’s overall structure, the company said

–  The company’s exhaust energy distribution technology, developed in response to the increased difficulty of emission control caused by improved combustion, led to reconstruction of the exhaust system design. The technology adapts to the demand for exhaust gas recirculation while ensuring the efficiency of turbochargers, meeting regulations and standards, and achieving 1% increase in brake thermal efficiency.

– Weichai said its subzone lubrication technology, developed based on the different characteristics of the friction pairs of the system, uses several friction reduction technologies to reduce the overall friction by 20%.

– Weichai said its Wise control technology takes advantage of a self-designed ECU by developing a series of more precise control predictive models, making every part of the diesel engine more efficient.

In addition to its common rail fuel system with injection pressure of 2500 bar (36,000 psi), Bosch also contributed its full technical know-how in fuel injection systems. When it comes to commercial vehicles, especially when heavy loads have to be transported over long distances, Bosch said the diesel engine will remain the preferred choice for the foreseeable future. For that reason, Bosch and Weichai said they aim to steadily refine the technology with an eye to protecting the climate and environment.

Bosch and Weichai launched their joint development project in September 2018. “Bosch offered great support on the breakthrough and unprecedented achievement of 50% efficiency in Weichai commercial-vehicle diesel engine,” said Tan Xuguang, chairman of the Weichai Group. “We’re very pleased to be continuing our highly successful partnership with Bosch.”

Bosch and Weichai, China’s largest manufacturer of engines for commercial vehicles, began their strategic alliance in 2003. Beyond engines, the two companies are also collaborating in other areas, including mobile fuel cell and driver assistance systems.

Weichai said it has received strong support from Bosch Group and other global suppliers and R&D consulting firms in the development of this program. Weichai’s future plans include partnering with more global companies to move toward a goal of 55% thermal efficiency, Xuguang announced during the ceremony.