Bosch’s New Breakthrough Diesel Technology – Explained

What stage is Diesel Technology at right now?

Diesel combustion engine technology has been one of the most innovative advancements in the modern automobile industry but has been recently been put to bed by many manufacturers and consumers. Diesel internal combustion technology was invented in the 19th century by mechanical engineer Rudolf Diesel. The diesel engine utilized diesel fuel instead of petroleum or gasoline and a 4 stroke piston cycle to produce rotational motion (torque) to propel a shaft. Diesel engines did not take off as the primary production car engine technology in the 20th century due to popularity and abundance of petrol solutions. But the late 20th and early 21st centuries witnessed a re-birth in diesel cars as the popularization of Engine Control Units and fuel injection allowed its engines to be comparatively more fuel efficient and cheaper than gasoline engines. Diesel cars were in addition easier to maintain, due to the lack of spark plugs, and more environment friendly thanks to their lower CO2 emissions. Through the 2000s, diesel was deemed by many as the alternative to petrol fuels.

However, recent tighter emissions tests and consumer complaints have significantly reduced the adoption of diesel technology and dimmed its future scope. In fact:

  1. European market share for diesel cars has fallen from 52% to 45% from 2015 to late 2017
  2. Diesel car sales fell by 23.6% in May 2018 in the UK over the period of one year
  3. Sales of hybrid and electric vehicles in Europe grew by over 36%
  4. Toyota’s total diesel sales in Europe (the largest diesel consumer) were an all time low of 15%, down from 30 percent in 2012. Toyota has since ended its diesel vehicle production due to this fall in demand.

The future for diesel technology does not look any brighter as analysts from the consulting firm AlixPartners point at an only 5% diesel market share in the European Union by 2030. This decline in the mass consumer market has been primarily fueled by the toxicity and greenhouse effect produced by diesel combustion, the biggest culprit being NOx (Nitrous Oxide). This large drawback of diesel vehicles was vastly popularized to consumers through the 2015 Volkswagen Dieselgate scandal which involved fake emissions test data from multiple models of the German automaker in Europe.

 

Boschs’s Solution to this Diesel Problem

However, recently the Bosch, a leading internal combustion engine supplier, has grabbed many manufacturers’ attention as they hope to revive the over a century old diesel combustion engine with a new simple and cost effective solution. The German engineering giant claims to have developed a new system to popularize diesel engines in the European market and allow manufacturers to pass the rigorous emissions tests plaguing hindering modern diesels.

Bosch’s new Bosch Diesel Technology, aptly named, is not meant to be a radical re-invention of the pre-exisiting diesel engine system, but rather a modular “component” type technology capable of being attached to standard diesel systems. This is where massive amounts of cost savings hope to take place as the company begins the process to regain a sizable market for the “cleaner” and vastly more efficient diesel fuel.

There’s a future for diesel. Today, we want to put a stop, once and for all, to the debate about the demise of diesel technology.-Bosch CEO, Dr. Volkmar Denner

What is the obstacle?

The primary issue this technology is designed to tackle is the dangerous Nitrogen Oxide (NOx) gas that is released when diesel combusts. Since 2017 in Europe, an extensive mandatory emissions test by the name of RDE (Real Driving Emissions) is conducted on all diesel vehicles planning to sell to the mass market. The RDE is designed to measure gas emissions from a vehicles exhaust system in varying conditions, they include:

  • Regular city driving (low speed with low load)
  • Highway driving (high speed with high load)
  • Backroads driving (medium speed with medium load)
  • Heavy traffic driving (extreme low speed with low load)
  • Varying ambient temperatures (affecting air/fuel ratio and combustibility)
A Bosch RDE Test Mule

 

Current regulations require vehicles to expel no more than 168 milligrams of NOx gas per kilometer of travelling. This limit applies strictly to all of the above conditions. Most modern petrol engines have had almost no issues containing this limit however diesel engines are rare to pass this requirement due to their inherent fuel. This is the problem this Bosch Diesel Technology hopes to remedy.

How does it work?

Research at Bosch’s headquarters in Stuttgart, Germany conducted multiple tests on the by-products of diesel fuel combustion. The main gases and elements emitted through diesel combustion include:

-Nitrogen Oxide (NOx)

-Carbon Monoxide (CO)

-Hydro Carbons (Soot/Particles) (HC)

 

  1. The exhaust system of modern automobiles are fitted with complex devices such as the Catalytic Converter (shown above) to filter out the toxic gases produced by internal combustion engines during cycles. The 3 way catalyst above uses bases and redox (reduction – oxidation) reactions to convert NOx, CO and HC to gases significantly less harmful than the ones originally inputted. Governing bodies today require consumer vehicles to be fitted with such systems to minimize greenhouse effects and keep civilians safe. Bosch engineers inferred that Nitrogen Oxide, the problematic gas, can be fully oxidized through the converter at exhaust temperatures of +200 C. To achieve these temperatures through the catalytic converter, Bosch developed a “sophisticated thermal management” system monitor and maintain hot temperatures.  AdBlue additive’s were also researched and implemented by Bosch this new diesel system.
  2. AdBlue chemicals are carbamide solutions capable of dissolving NOx gases. Carbamide, also known as Urea is an organic compound that helps in the metabolism of Nitrogen.

3. In addition, a revised turbocharger setup can be implemented to diesel engines. These setups will use separate high pressure and low pressure exhaust manifold channels (the exhaust pipelines that feed to the turbocharger’s turbine – RED). Such a turbocharger setup can improve startup fuel efficiency by optimizing the air fuel ratio needed to crank the engine. This will also come in handy to aggressive drivers who demand quick throttle responses. High pressure air channels can be opened and closed by the Engine Control Unit. Below is a diagram explaining the process of turbocharging a combustion engine.

  • During the exhaust phase of a cycle, the turbine wheel will convert excess thermal energy from the gases to useful rotational energy
  • This rotational energy will be used to pull in air for the intake stroke of the cycle.
  • Once pressurized air has been pulled, the air is sent through an intercooler to reduce its temperature. After which the air is forced into the combustion chamber for ignition.

4. Bosch’s new diesel system combines the smarter turbocharger and thermal regulators with a tuned Engine Control Unit (ECU) to optimize the control of the air fuel ratio and exhaust valves.

A typical Turbocharger setup

 

Bosch Q and A session

Below is a Q and A session with a chief engineer borrowed from Bosch’s website that discusses the future and applications of a technology such as this towards the automotive market.

When will the technology be ready for production?

Bosch’s new diesel system is based on components that are already available in the market. It is available to customers effective immediately and can be incorporated into production projects.

Why is urban driving more demanding than extra-urban or freeway driving?

To ensure optimum NOx conversion, the exhaust gases must be hotter than 200 degrees Celsius. This temperature is often not reached in urban driving, when cars are stuck in gridlock or stop-and-go traffic. As a result, the exhaust system cools down. Bosch’s new thermal management system remedies this problem by actively regulating the exhaust gas temperature.

Does the temperature regulation require an auxiliary 48-volt heater installed in the exhaust-gas system or additional components of a similar kind?

Bosch’s new diesel system is based on components already available in the market and does not require an additional 48-volt on-board electrical system.

Will the new Bosch technology make the diesel engine significantly more expensive?

The Bosch diesel technology is based on components already in use in production vehicles. The decisive advance comes from a new combination of existing technology. It does not require any additional hardware components. So reducing emissions will not make diesel vehicles any less affordable.

Will the diesel engine lose its comparative advantage in fuel economy and climate-friendliness as a result of the new technology?

No. Our engineers’ goal was clear: to reduce NOx emissions while retaining the diesel’s comparative advantage in terms of CO2 emissions. Diesel will thus remain a climate-friendly option.

How much engineering effort went into the new diesel technology?

Over the past few years, roughly 100 engineers have been involved in work on the new technology. The total cost ran into eight figures.

 

As of 2020, the NOx limit will be strictly cut to 120 miligrams/km from 168 miligrams/km in the EU. This Bosch technology can achieve around 13 milligrams of NOx in standard RDE tests, well below of that defined by regulations today and in 2020. In urban conditions,  the average emissions of the Bosch test vehicles were around 40 milligrams per kilometer!

Bosch delivered demoed their diesel exhaust technology at a major press event in Stuttgart, Germany. Dozens of journalists, from both Germany and abroad, had the opportunity to drive test vehicles equipped with mobile measuring equipment in heavy city traffic, under challenging conditions. Bosch hopes to sell this technology to large scale automakers like Mercedes Benz, BMW, VW and GM in the future in the hopes to provide a friendlier internal combustion engine before the advent of the electric transportation revolution!

 

Sources –

https://www.ft.com/content/d506be90-682d-11e8-b6eb-4acfcfb08c11 

BBC – https://www.bbc.com/news/business-44687784 

Bosch Website – https://www.bosch-presse.de/pressportal/de/en/breakthrough-new-bosch-diesel-technology-provides-solution-to-nox-problem-155524.html